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Water and Energy Optimization Grand Canyon National Park Wastewater Treatment Plant Energy Use Evaluation Water/Energy Best Practices Guide for Rural Arizona’s Water and Wastewater Systems January 2009 A Partnership Project of Grand Canyon National Park Ecological Monitoring & Assessment Program, Northern Arizona University In collaboration with the Arizona Water Institute Stephen Mead, PhD, Construction Management, NAU Charles Schlinger, PhD, Civil and Environmental Engineering, NAU William Auberle, Professor, Civil and Environmental Engineering, NAU Matthew Roberts, Civil and Environmental Engineering, NAU B. Billy, NAU R. Cassavant, NAU

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Water and Energy Optimization

Grand Canyon National Park Wastewater Treatment Plant Energy Use Evaluation

Water/Energy Best Practices Guide for Rural

Arizona’s Water and Wastewater Systems

January 2009

A Partnership Project of Grand Canyon National Park

Ecological Monitoring & Assessment Program, Northern Arizona University In collaboration with the Arizona Water Institute

Stephen Mead, PhD, Construction Management, NAU Charles Schlinger, PhD, Civil and Environmental Engineering, NAU

William Auberle, Professor, Civil and Environmental Engineering, NAU Matthew Roberts, Civil and Environmental Engineering, NAU

B. Billy, NAU R. Cassavant, NAU

Grand Canyon National Park, Arizona Wastewater Treatment Plant Energy Use Evaluation

by Matt Roberts Northern Arizona University

January 11, 2009

Table of Contents 1.0 Introduction............................................................................................................................... 3

1.1 Contemporary Relevance.............................................................................................. 3 1.2 Project Overview .......................................................................................................... 3 1.3 Role of National Park Service....................................................................................... 3 1.4 Wastewater Service at GCNP ....................................................................................... 3

2.0 Wastewater Treatment Plant ..................................................................................................... 4 2.1 Treatment Process......................................................................................................... 4 2.2 Drying Beds .................................................................................................................. 4 2.3 Current/Future Issues .................................................................................................... 5

3.0 Results....................................................................................................................................... 5 3.1 Costs per Year for Wastewater Treatment.................................................................... 5 3.2 Energy Use per Thousand Gallons ............................................................................... 5

4.0 Best Practice Recommendations............................................................................................... 5 4.1 Minimal to No Cost ...................................................................................................... 5 4.2 Low to Moderate Cost .................................................................................................. 5 4.3 Moderate to High Cost.................................................................................................. 6

5.0 Acknowledgements................................................................................................................... 6 6.0 References................................................................................................................................. 6

1.0 INTRODUCTION

1.1 Contemporary Relevance One of the natural wonders of the world, Grand Canyon National Park attracts thousands of visitors every day. Linked water and energy utilization at the Park by its considerable wastewater system is an ongoing concern. Throughout the world, the supply, transmission, pumping, treatment and distribution of water and wastewater accounts for 2-3% of all energy consumed, while at the Park, the treatment of wastewater alone uses over 12% of the energy budget.

1.2 Project Overview The Arizona Water Institute (AWI) and the Grand Canyon National Park co-sponsored a larger study to develop a Best Practices Guide intended to promote greater energy efficiency and reduce overall water use by rural Arizona water and wastewater systems. As part of the larger study, several case studies of individual systems were completed, and the wastewater system at the South Rim of Grand Canyon National Park was at the focus of one case study, which is detailed here. Electrical power consumption and wastewater treatment data were used to develop values for a commonly-used metric, which is the number of kilo-Watt-hours per kilo-gallon of water (kWh/kgal). This metric allows comparison to other facilities of similar size and has been widely used in the industry.

1.3 Role of National Park Service The National Park Service (NPS) has contributed to the overall study by providing funding to underwrite the Grand Canyon National Park wastewater system case study, and to partially underwrite the development of the Best Practices Guide. With little reserve time available, Park Service staff kindly provided a tour of their wastewater facility at the South Rim, provided water and energy use data for their system, and offered considerable insight into the workings of the South Rim wastewater system.

1.4 Wastewater Service at GCNP Grand Canyon National Park spans over 1,218,375 acres1 (1904 sq. mi.). The NPS provides wastewater services for both the North Rim, and the South Rim. The South Rim includes three distinct systems. The largest treatment facility services the South Rim proper. Two much smaller stand-alone facilities treat wastewater at Desert View and at Hermit’s Rest. About one-third of the reclaimed water produced at the South Rim is reused for toilet flushing, firefighting, and irrigation at the South Rim. Due to funding and time limitations, only the South Rim wastewater treatment plant was evaluated as part of this project.

2.0 WASTEWATER TREATMENT PLANT

2.1 Treatment Process The current wastewater treatment plant was built in 1975. A second phase of construction in 1985 was an upgrade to allow reclaimed water production. The existing system is a 6th generation wastewater treatment facility that has operated at Grand Canyon National Park’s South Rim. The collection system is a gravity-fed sewer from points of generation to the treatment plant, with an average inflow of 500,000 gallons per day. Influent grit removal is the first step of the treatment process. A bar screen is continuously actuated and is raked clean every 15 minutes. Soda ash is then added to balance the pH to 7.2-7.5 in advance of aeration. The aerators are 1-inch coarse-bubble diffusers, spun by three 15-hp motors and two 50-hp motors, with compressed air being supplied by two 75-hp air compressors. There are four 3-hp pumps for activated sludge return, operating at about 100 gpm. After the aeration basins, the wastewater flows down to an alum-based coagulation/flocculation station and secondary clarifier, where two 1-hp motors assist in the coagulation/flocculation and a ½-hp motor runs the sludge rake at the bottom of the tertiary clarifier. After flowing over anthracite, the effluent is disinfected with chlorine gas before discharge to the Coconino Wash, or reused within the Park. A schematic of the wastewater system is presented in Figure 2.1, below.

Figure 2.1: Wastewater Treatment at Grand Canyon National Park

Anthracite Filter

Bar Screens

Soda Ash Addition for pH Control

Influent: 500,000

gal per day Grit

Chamber

Addition of Alum for

Coagulation & Flocculation

Secondary Clarifiers

Tertiary Clarifiers

Grit Hauled to Landfill Digester

Aerator

Aerator

Sludge Hauled to Drying Beds

Drying Beds Convert Biosolids from Class

B to Class A for Landfill Capping

Disinfection with Chlorine

Gas

Effluent Discharge to Coconino Wash and Reuse within

National Park

Activated Sludge Return

2.2 Drying Beds All bio solids (including mule dung) from the Grand Canyon National Park (including the North Rim, but excluding Desert View) are delivered to the South Rim WWTP facility, where they are converted in drying beds from class B to class A solids for use in landfill capping.

2.3 Current/Future Issues An issue with the discharge of effluent into Coconino Wash is that some springs discharging below the south rim have elevated nitrate levels, possibly due to infiltration of the effluent into ground water. Dave Wellborn of NPS reports that what is discharged into the Coconino Wash often never leaves the park boundary, infiltrating into the ground very quickly. Another issue with discharging reclaimed water effluent is that its copper concentrations are elevated, exceeding SDWA maximum contaminant levels, mostly because the drinking water also contains copper.

3.0 RESULTS

3.1 Costs per Year for Wastewater Treatment Electricity used in the treatment of wastewater at the South Rim WWTP costs $51,100 annually.

3.2 Energy Use per Thousand Gallons Averages of electricity used per thousand gallons (kWh/kgal) for the wastewater system are summarized in Table 3.1, below.

Table 3.1: Energy Use per 1000 Gallons Water Average Wastewater Influent Flow Electricity Use Wastewater Annual Power Use Wastewater

182.5 Mgal / year 500,000 gal / day

347.2 gpm 8.5 kWh / kgal 1,547,040 kWh / year

$51,100 / year

Mgal=millions of gallons, kgal=thousands of gallons, gpm=gallons per minute Sources: National Park Service, Arizona Public Service

4.0 BEST PRACTICE RECOMMENDATIONS

4.1 Minimal to No Cost • Assess the need of the tertiary treatment of wastewater: it is rarely done in comparable systems • Involve plant operators, maintenance staff, and engineers in scoping, design and specification for

future projects. • Assess costs of maintaining existing facilities versus upgrading over the expected life of the

system. • Allow the bar screen rake to rise only enough to expose more clean bar screen, letting excess

water drip off before deposition in a dumpster, thereby not hauling excess water weight to the landfill.

4.2 Low to Moderate Cost • Evaluate pumps, blowers, and motors for upgrade to high-efficiency or VFD. • Evaluate the feasibility for dissolved-oxygen sensor-based control over aeration. • Create financial or other incentives for water users to conserve instead of increasing plant

capacity. • Perform a loss/leakage survey for both reclaimed water and influent wastewater.

• Directly utilize heat potential in blower/pump room to keep biological activities warmer and thus more reactive or to heat nearby buildings in the winter.

• Use energy efficient lighting at the wastewater treatment plant. • Evaluate the feasibility of using an anaerobic digester to handle bio solids to generate natural gas

for use within the Park.

4.3 Moderate to High Cost • Change coarse-bubble diffusers to fine-bubble diffusers to increase the aeration efficiency. • Utilize photovoltaic cells or other renewable energy sources wherever possible throughout the

wastewater system.

5.0 ACKNOWLEDGEMENTS A special thanks goes out to Steve Rice for coordinating efforts between Flagstaff and Grand Canyon, Dave Wellborn for giving an overview of the potable water supply system and some insight into reclaimed water reuse and discharge, Pat Mathis for guiding a tour through the wastewater treatment plant, Mike Martin for extended insight and information, and Don Keil for providing specific energy use data.

6.0 REFERENCES 1 National Park Service. Accessed on 8 August 2008. Available from: <http://www.nps.gov/grca/naturescience/index.htm> 2 “Water Supply and Wastewater Reclamation South Rim Grand Canyon National Park Arizona: A Study for the National Park Service.” CH2M Hill. 1973. 3 “Grand Canyon National Park Water Supply Appraisal Study.” Bureau of Reclamation. 2002. 4 “Water Resources Management Plan.” Grand Canyon National Park. 1984.

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems

By

S. P. Mead – NAU C. M. Schlinger – NAU W. M. Auberle – NAU

B. Billy – UA R. Casavant – UA

M.S. Roberts – NAU

January 11, 2009

Table of Contents Introduction........................................................................................................................ 4 Background ........................................................................................................................ 5

State and federal correctional facilities.ural Arizona Water and Wastewater System Attributes.......................................................................................................... 6 Direct and Embedded Energy Demands..................................................................... 6 Energy Usage in Water and Wastewater Systems..................................................... 7 Water Used in Energy Production .............................................................................. 8 Basic Energy and Water Uses in Water and Wastewater Systems.......................... 9 Greenhouse Gas Emissions .......................................................................................... 9

Best Practices for Water and Energy Conservation ....................................................... 10 Water Management and Policy ................................................................................. 10

1. Balance Revenue and Expenses when Operating Water and Wastewater Systems........................................................................................................ 10

2. Understand How Energy and Water are Utilized in Water and Wastewater Systems........................................................................................................ 11

3. Develop a Cost Analysis and Implement Capital Improvement Planning ........ 12 4. Implement a Water Conservation Program........................................................ 13 5. Develop Water Audits and Implement Leak Detection..................................... 14 6. Implement Water Budgets and Rate Structures ................................................. 15 7. Create Financial Incentives for Water Customers ............................................. 16 8. Adopt Water Efficient Ordinances and Codes................................................... 18 9. Create Water Education Programs..................................................................... 19

System Design and Engineering ................................................................................ 20 10. Review System Plans, Specifications, and Records................................ 20

11. Take Measurements, Evaluate the Data, Make Decisions................................. 20 12. Evaluate Different Available Water Sources and Their Costs........................... 21 13. Reduce Leakage through Pressure Management ............................................... 22 14. Reduce Energy Losses in Pumps & Fans .......................................................... 22 15. Reduce Friction Losses in Production Wells ..................................................... 23 16. Reduce Friction Losses in Valves...................................................................... 23 17. Reduce Friction Losses in Pipes ........................................................................ 23 18. Adequately Ventilate or Sunshield in Warm Weather....................................... 24 19. Use Gravity to Move Water............................................................................... 24 20. Automate System Operation .............................................................................. 24 21. Generate High-Quality WWTP Effluent ........................................................... 24 22. Consider Hydroxyl Ion Fog for Wastewater Odor Control ............................... 25

Operations and Maintenance..................................................................................... 25 23. Manage Air in Pressurized Water and Wastewater Systems ............................. 25 24. Utilize Off-Peak Power Usage Strategies .......................................................... 25 25. Optimize Treatment Processes to Reduce Water and Energy Consumption..... 26 26. Coordinate Water Production / Delivery with Treatment Process Capacity ..... 26 27. Retrofit Facilities with Energy-Efficient Lighting............................................. 27 28. UV Disinfection Systems Best Practices ........................................................... 27 29. Increase Electrical Motor Efficiency ................................................................. 28 30. Operations and Maintenance (O&M) Guides and Education & Training ......... 28

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 2

Renewable Energy ...................................................................................................... 28 31. Wind Energy ...................................................................................................... 29 32. Solar Energy....................................................................................................... 29

Acknowledgments............................................................................................................. 30 References ........................................................................................................................ 30 Appendix 1 – Design Best Practices Checklists for New Water and Wastewater Facilities ........................................................................................................................... 37 Appendix 2 – Funding Sources, Renewable Energy Specialists, and Other Resources39 Appendix 3 – Case Study Summaries.............................................................................. 41

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 3

Introduction In Arizona, water is one of the keys to economic development and quality of life. Arizona’s water and wastewater systems use significant amounts of electrical energy, and the generation of that energy often generates greenhouse gases (GHG) that have been associated with global warming. Water is also closely tied to Arizona’s industrial sector where substantial amounts are used for cooling at power plants, agriculture, and for mining and manufacturing operations. Arizona’s water infrastructure is both extensive and diverse, with systems that range in size from complex water supply facilities, run by entities such as the Central Arizona Project, to smaller water systems operated by rural communities, state and federal agencies, tribes, and private entities. According to the U.S. Census 2000, approximately 25% of Arizona’s population lives outside of the urban centers in Maricopa, Pinal and Pima counties. Typically, these rural communities have populations of less than 50,000 people. A report by the University of Arizona Water Resources Research Center (Gelt, 2000) suggests that many of these communities lack the management resources to administer effectively their water resources. While urban utilities have a highly-trained cadre of water professionals, small communities often must rely on a patchwork of national, state and regional agencies for technical expertise. At the same time, the inadequate tax base of many rural communities hampers their ability to commission evaluations of their operations, systems and needs. According to the report, these problems “leave rural officials without the means to contract needed expertise and services to support water management efforts”. Given these challenges, this “best practices” guide was developed to help rural Arizona managers and operators of public and private water and wastewater systems meet future water and energy challenges in the most effective manner possible. The authors have investigated the “best practices” for innovative water and energy utilization by small- to medium-sized water and wastewater systems in the United States, Europe, and elsewhere, to identify, evaluate, and prioritize technologies and strategies that can be used by rural Arizona providers to conserve water, to reduce energy usage and related expenditures, and to minimize GHG emissions. In short, this guide is designed to help “green” the water infrastructure of rural Arizona, and assist rural water and wastewater providers in their efforts to meet ongoing and future water and energy challenges in the most effective manner possible.   The best practices in this guide are organized under four themes:

Water Management and Policy System Design and Engineering Operations and Maintenance Renewable Energy

In addition, this report provides summaries for seven case studies (Appendix 3) completed on small water and wastewater systems in rural Arizona. These case studies

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 4

are intended to illustrate the possible applications to real Arizona water and wastewater systems of concepts and practices presented in this guide.

Background The United States Environmental Protection Agency (USEPA) considers “small” water systems to be those systems serving between 500 and 3,300 individuals. Similarly, “very small” water systems typically serve 500 people or less. Collectively, there are nearly 147,000 such small and very small systems in the U.S. serving nearly 40 million individuals, or nearly 13% of the population. In Arizona, nearly 1,600 drinking water systems are permitted through the Arizona Department of Environmental Quality (ADEQ). About a dozen of these are for towns and cities that serve populations in excess of 10,000. Thus, most Arizona systems serve populations of fewer than 500, and many serve less than 50. Similar trends hold true for the nearly 900 wastewater systems permitted through ADEQ (personal communication, Bill Reed, ADEQ, 6/30/2008). In addition to ADEQ-permitted systems, there are many small systems, including many systems that exclusively serve school populations, in the numerous sovereign Native American communities across the state. It is these small rural Arizona water and wastewater systems that are at the focus of this guide. There are a variety of rural system operators/owners in rural Arizona. Some examples include:

Towns and cities, such as Benson, Winslow and Tuba City; Improvement districts, such as Coconino County’s Kachina Village Improvement

District (KVID); Private entities, including developments such as Forest Highlands near Flagstaff; Private water and wastewater utilities such as Arizona Water Co and Global

Water Co.; The Bureau of Indian Affairs (BIA), dedicated tribal utilities such as the Navajo

Tribal Utility Authority (NTUA), and sovereign nations, such as the Ak-Chin Indian Community;

Water councils and other organizations in small communities, such as Sipaulovi Village on the Hopi Reservation;

Industrial and mining systems (Chemical Lime Company in Nelson near Peach Springs; Phelps Dodge’s Morenci and Clifton mines, etc.);

Arizona State Parks and Arizona Department of Transportation rest area systems; Department of Defense facilities, such as Fort Huachuca, Luke Air Force Base,

and the Yuma Proving Ground; National Park Service (NPS) systems, such as those operated at Grand Canyon

National Park;

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 5

State and federal correctional facilities.ural Arizona Water and Wastewater System Attributes Water and wastewater facilities in rural Arizona have several defining characteristics:

Though there are some exceptions, Arizona wastewater treatment facilities generally rely on proven simple processes that require a low or minimal level of operations and maintenance (O&M);

Wastewater treatment often is based on facultative lagoons, some aerated and some not, or utilizes oxidation trenches/ditches;

In some places, lagoons are permitted to discharge directly to waterways (e.g., White River, Arizona);

A common wastewater treatment process is package plants that use activated sludge;

Where utilized, disinfection is typically achieved using liquid/tablet chlorination (UV disinfection is uncommon at small treatment facilities);

Raw water, with some important exceptions (e.g., Page, CAP water consumers), is generally supplied by groundwater sources;

In some instances, groundwater sources are deemed to be under the influence of surface water, and filtration is required;

Typically, water treatment consists solely of disinfection; Less often, groundwater supplies are treated to achieve: fluoridation; fluorine

reduction; taste / odor control; arsenic reduction; herbicide / pesticide reduction; or nitrate reduction.

(The above is a synthesis developed from conversations on 6/30/2008 with Bill Reed of ADEQ and on 7/3/2008 with Vern Camp of the Arizona Small Utilities Association.)

Direct and Embedded Energy Demands There are several accounting methods used to track energy when considering its utilization in water and water systems, its cost, and its conservation. Direct energy is the result from an accounting which takes into consideration energy that exists, is delivered, is purchased, is sold, etc., in the form of: chemical energy (gasoline, diesel fuel, natural gas, propane, methane from wastewater treatment plant sludge digestion); electrical energy; or thermal energy (a certain amount of material, such as air, water, iron, etc., at a certain temperature). Embedded energy is the result from an accounting which quantifies the total energy used to extract, manufacture, transport and dispose of a product or service. For example, if an organization purchases sodium hypochlorite for use in water disinfection, the cost paid for that product presumably includes the energy expense incurred by the manufacturer when it created and packaged the product, and the energy expenses of transport and storage before it came into the user’s possession. There may be embedded energy in a

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 6

product for which one does not pay the supplier. For example, part of the the cost of a new service vehicle is for the energy expended as part of production, assembly and transportation to the dealer. As another example, the coal burned at an electrical generating station contains energy supplied, millions of years ago, by the sun, which aided photosynthesis by plants, which were, subsequently, over geologic time, converted into coal. Water that is purchased from a wholesaler, or utility, such as the Central Arizona Project (CAP), has embedded energy. Part of the cost to a buyer of CAP water is used by CAP to defray expenses for energy and other expenditures incurred to store (e.g., in Lake Pleasant), lift (pump stations), or transport (via canals) the water. The energy expenditures come about principally for operating pump stations, and, to a lesser extent, for heating, cooling, and lighting of facilities, and powering vehicles used by employees, etc. Other expenditures arise due to employee salaries, employee benefits, etc. If an organization pays $250 for an acre-foot (43,560 cubic feet, or 325,000 gallons) of CAP water, some significant portion of that $250 is for energy expended by CAP to deliver that water to the user. The same concept applies to water provided by a small rural Arizona water utility. If a household pays $7.50 per 1000 gallons of potable water, a significant portion of the $7.50 is for the energy expenditures to lift, pressurize and treat the water. Similarly, treated effluent that is discharged by a wastewater utility has embedded energy, due to the pumping, treatment, aeration, and other processes that require energy inputs. The fee to a commercial enterprise for disposing of its wastewater into the utility’s collection system covers the cost of the energy. Often, wastewater fees and water fees are lumped, since it is easy to meter water deliveries and less so to meter wastewater discharges!

Energy Usage in Water and Wastewater Systems As a nation, the United States devotes nearly 4%, or 164 million Mega-Watt-hours (MWh), of our electrical energy generation, to handle, lift, move, pressurize, distribute, and treat our water. Typically, this energy usage, or energy intensity, may be expressed either in terms of kilo-Watt-hours (kWh) per acre-foot of water (kWh/ac-ft) or in terms of kWh per 1,000 gallons of water (kWh/kgal). A comprehensive study (Cohen et al., 2004) concluded that the average energy intensity for California water usage from source through the end use and continuing through discharge from a wastewater treatment plant is approximately 7000 kWh/ac-ft (21 kWh/kgal). End use energy – which includes the energy required to heat or cool water in homes and industry – requires 3900 kWh/ac-ft (12 kWh/kgal). Source / conveyance energy uses 2040 kWh/ac-ft (6.3 kWh/ac-ft), while distribution uses 330 kWh/ac-ft (1.0 kWh/kgal). Wastewater treatment uses approximately 570 kWh/ac-ft (1.7 kWh/kgal), while water treatment requires 60 kWh/ac-ft (0.2 kWh/kgal).

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 7

According to these values, in California, the end use energy intensity accounts for more than 50% of the total. According to the United States Geological Survey (USGS) (Solley et al., 1998), residential usage accounts for nearly 26% of the water used in the United States. Dependent on locale, single family and multi-family dwellings use between 50% and 80% of billed water demand, and the average household uses 100 gallons, per capita, per day. Approximately, 68% of residential water is used inside the home, while 32% is used outside to irrigate plants and lawns. Other studies, with a focus purely on water and wastewater utilities / systems, have considered only the energy intensity embedded in the water delivered to the end user, and the energy intensity embedded in wastewater after its release by the end user to the wastewater utility. For example, a study (Elliott et al., 2003) of Wisconsin drinking water facilities revealed that the median value of energy intensity was about 1.5 kWh/kgal, considering both surface-water-using and ground-water-using facilities. (The State of Wisconsin [Cantwell, 2008] has an entire program, Focus on Energy, that offers energy information and services to Wisconsin utility customers.) EPRI (1996) reported results from an investigation of water supply and treatment facilities and found that surface-water-supplied plants use on average 1.4 kWh/kgal while groundwater-supplied facilities used, on average, 1.8 kWh/kgal. deMonsabert and Liner (1996) studied federal facilities and reported approximate energy demands of 2 kWh/kgal for water treatment and 3 kWh/kgal for wastewater treatment plants.

Water Used in Energy Production While not the focus of this guide, it is nonetheless important to keep in mind that large amounts of water are used in the production of electrical energy. According to the Energy Information Administration (EIA), in Arizona nearly 104.4 million MWh of electrical energy was generated in 2006. Of that total, the breakdown by energy sources is as follows:

coal: 38.7%; natural gas: 31.5%; nuclear: 23.0%; hydroelectric: 6.5%; petroleum, renewables other than hydroelectric, and pumped storage: 0.3%.

Across the U.S., electrical energy generation averages over 2 gallons of water usage for every kWh generated (Torcellini et al., 2003). Pasqualetti (personal communication, 2008) has estimated that, for electricity produced from Arizona hydroelectric sources, water usage for those facilities can, on average, be as high as 65 gallons/kWh. However, because most of Arizona’s electrical generating capacity is thermo-electric (coal, gas, nuclear) the average water use at Arizona electrical generating facilities is near 8 gallons/kWh (Torcellini et al., 2008). This is four times higher than the national average.

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 8

Basic Energy and Water Uses in Water and Wastewater Systems In water and wastewater systems, energy is used to lift (overcome gravity), move / transport (overcome friction), heat, cool, pressurize, and treat water. Actual treatment consists of pressurization, transport/lifting, filtration, addition and removal of chemicals, aeration, etc. Additionally, energy is used to heat, cool, or pressurize air. Finally, energy is used for lighting, heating, ventilating, air conditioning (HVAC), and telecommunications at wastewater facilities, as well as for transportation of employees, equipment, etc. For the purposes of this guide it is useful to use the the following elements to describe the water and energy usage of of water supply systems: supply/source; transmission, distribution, and storage; pumping; treatment; end use(s). Similarly, this guide uses the the following elements to describe water and energy usage in wastewater systems: collection; pumping; storage; treatment; reuse / discharge.

Greenhouse Gas Emissions Users and producers of energy through the combustion of fossil fuels recognize that reducing emissions of GHGs is increasingly important. Voluntary reductions of carbon dioxide emissions are now encouraged, but rapidly developing state, regional, national, and international policies will mandate reduced emissions of GHGs. Thus, meeting Arizona’s energy needs will become increasingly expensive. In general, a savings of 1 kWh of electrical energy translates to a reduction of nearly 1.5 pounds of greenhouse gas emissions (Arizona Climate Change Advisory Group, 2006; Dones et al., 2003).

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 9

Best Practices for Water and Energy Conservation In preparing this guide, we have focused on energy and water conservation practices for small rural water and wastewater systems, about which little has been written. On the other hand, there are many studies, investigations and reports concerning larger systems, from which generalities have emerged. The results on larger systems were used to identify processes, systems and components for initial review and consideration. Concerning larger water supply systems, Berry (2007) reports that the most promising areas for intervention are: improving pumping systems; managing leaks; automating system operations; and, regular monitoring, with metering, of end use. For larger wastewater systems, Elliot (2003) found that aeration, sludge treatment, and pumping offer the greatest potential for reducing energy costs. We expect that a similar set of best practices will yield the most bang for the buck when it comes to small rural water and wastewater systems, although that premise is untested. Therefore, it is essential to complete a cost analysis (best practice #3, below) before proceeding with any major improvement or adjustment.

Water Management and Policy

1. Balance Revenue and Expenses when Operating Water and Wastewater Systems

To provide baseline data, utilities should strive to track expenses and revenues associated with current operations and maintenance, and assess the success of best water and energy conservation practices after implementation. As part of this practice, it is essential to review routinely and, if necessary, adjust water and wastewater rates. Rate setting can be politically charged, but it is critical for long-term, and possibly short-term viability of a water or wastewater utility, whether private or public. The subject of rate setting is mostly beyond the scope of this guide, but the American Water Works Association (AWWA, 2000) has issued a manual that provides guidance; and there are many other references on this topic. Consult Best Practice 6 in this guide,for information on water budget-based rate structures. Success with this and any other rate-related practice requires periodic communication with end-users so they: 1) are aware that efforts to conserve water and energy do result in reduced demand for both renewable and non-renewable natural resources – which benefits all; and, 2) help to reduce future user expenses by reducing the need for ever-greater amounts of water and wastewater system infrastructure. End users also need to be informed that rate reductions, if they occur at all, are only a secondary benefit that may arise when best practices are implemented.

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 10

2. Understand How Energy and Water are Utilized in Water and Wastewater Systems

In order to reduce energy and water use in any system, it is important to understand the ‘where’, the ‘why’, and the ‘when’ of that usage.

For example, aeration in wastewater treatment typically consumes a significant fraction of overall facility energy usage. Aeration is required to facilitate aerobic decomposition of waste products in the wastewater; and large amounts of energy are required to power the blowers / compressors that supply the air necessary for aeration in conventional wastewater treatment plants, or to power mixing equipment in aerated lagoons. In many plants, the blowers or compressors operate at full capacity all of the time, whether or not it is necessary. It may be feasible to monitor dissolved oxygen (DO), or another indicator, in aerated waters and to adjust mechanized equipment operations accordingly.

The University of California at Davis (UC Davis) implemented aeration control using continuous DO monitoring at their campus wastewater treatment plant. Paraphrasing and quoting from the 2005 report by Phillips and Fan:

The original design for the 2000 UC Davis Wastewater Treatment Plant (WWTP) relied on manual aeration control to maintain desirable dissolved oxygen (DO) levels in the oxidation ditch. Given the large daily variation in flow and wastewater strength, WWTP operators found it difficult to maintain stable DO levels. As a result, operators typically erred by providing too much oxygen, and the ditch was often found to be in an over-aerated state. Thus, the control strategy wasted energy and promoted unstable biological conditions. In January 2004, UC Davis installed a new system for continuously measuring DO in the oxidation ditch and automatically controlling aeration: Over a 12-month period the use of Variable-Frequency Drives (VFDs) for oxidation ditch aeration in conjunction with DO feedback-loop control reduced WWTP electrical consumption by an average of 23% or 0.755 kWh/kgal. The project was found to have a 1.2 year payback at the prevailing municipal electrical rate of $0.09/kWh. Beyond energy efficiency, the ability to maintain DO at prescribed levels in the oxidation ditch has afforded operators a higher degree of biological process control. Effluent quality has improved as a result. The sludge volume index (SVI) increased from an average of 84 to 99. Ammonia as nitrogen has consistently remained below 0.5 mg/l after implementation.

In many water treatment facilities, backwashing of filters utilizes significant quantities of water. At a minimum, backwash rates and procedures should be reviewed for possible changes to lower water use. Also, to the greatest extent possible, overflows from basins and storage tanks, as well as leakage from such, should be eliminated.

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 11

In Ruidoso, New Mexico, the water utility has implemented backwash recycling at its water treatment plants in order to conserve water used in plant operations (Brand and Wilt, 2003). The “wet” water savings, due to backwash recycling at a new water treatment plant, were estimated at 30 ac-ft./yr. This represents 3% of total water deliveries to the plant.

For public health reasons, reuse of backwash water in a potable water facility must be approached carefully; it may not be allowed by the regulating authority, which in Arizona is ADEQ or USEPA (for tribal systems). Even if backwash water cannot be recycled as potable water, there may be other potential uses, such as dust control, construction water for soil compaction, etc. The Cedar Rapids, Iowa, water utility (Iowa Association of Municipal Utilities, Year unknown A) has an energy efficiency management program that addresses the needs of public, commercial and industrial users. The program consists of the following elements:

Maintaining electrical usage records and developing analytical methods to review the record data;

Monitoring and management of peak-demand power and the power factor(s); Equipment for real-time monitoring of power usage; Variable speed/frequency drives for pumps; Participation in the electrical provider’s power interruption management program; Citywide energy management system.

In all of these examples, a thorough understanding of how, where, and why energy and water were being utilized was needed before conservation strategies could be formulated and implemented.

3. Develop a Cost Analysis and Implement Capital Improvement Planning

Before making any significant investment requiring either money (capital) or labor, complete an economic evaluation that takes into account the annual cost of maintaining the status quo (an existing system configuration) in comparison to making improvements. This is often referred to as alternatives analysis. For example, it may appear, on the surface, that a facility could utilize renewable energy to support part of its energy demand. A complete analysis will consider all costs of implementing renewable energy: any borrowing cost(s), purchasing the equipment, installation, permitting, maintenance, operations, etc., in addition to the savings likely to be gained. This analysis will take into account capital costs, energy and other costs, interest, inflation, depreciation (possibly), operations and maintenance expenses, labor costs, etc. This type of analysis is typically completed by an engineer with expertise both in the water or wastewater systems under consideration and in engineering economics.

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If an alternatives analysis requires resources beyond those readily available, it may be possible to seek out the experiences and expertise of individuals who work for water or wastewater utilities that have completed such an analysis before they proceeded, or declined to proceed, with an upgrade similar to the one being contemplated. Once an alternatives analysis has been completed, it can serve as the basis for either staying the course, or making a change. The State of Washington offers energy life-cycle cost analysis (ELCCA) guidelines, spreadsheets and reports that address buildings. Pump Life Cycle Costs: A Guide to LCC Analysis for Pumping Systems is a detailed life-cycle cost (LCC) guide developed by the Hydraulic Institute, Europump, and the U.S. Department of Energy’s Office of Industrial Technologies (OIT).

4. Implement a Water Conservation Program Based on U.S. Census data, the U.S. population will grow by 30% over the next thirty years. In growing regions like the Southwest, large and small utilities will need to expand their operations. As noted earlier, end use or supplying water to homes and businesses is energy intensive, and, as demand and power costs rise, small utilities will be challenged by rising costs. Fortunately, the most cost-effective way to reduce water costs is to simply use less. As a result, water conservation programs are often the most cost-effective way to lower energy bills for both consumers and utilities (Cohen et al. 2004). Conservation can provide other system benefits as well. When utilities reduce the water that has to be pumped and treated, they reduce their water production and chemical expenses. Because conservation reduces the demand for water, a conservation program can also effectively increase system capacity, reducing the need for costly upgrades or expansions of existing facilities. Unfortunately, reduced water usage also means lower revenues for a utility. For water or energy conservation to be attractive to water and wastewater utilities, the implementation of best practices must be accompanied by parallel efforts to adjust rates so that expenses will continue to be met by revenue. Similarly, revenues to the system should not necessarily be an incentive to expand production. Generally, there are five approaches that utility managers can use to create effective conservation programs:

Water audits/& leak detection programs; Water budget/rate programs; Financial incentives; Ordinances/codes; Education.

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The State of Texas has developed an excellent comprehensive guide that outlines several conservation strategies in each of these areas (Texas Water Development Board, 2004).

5. Develop Water Audits and Implement Leak Detection  An old saying suggests, “what gets measured, gets done.” To implement a conservation program, often the best place to start is with a comprehensive water audit. Typically, a water audit uses a two-step approach where the system is looked at from the top down and then, from the bottom up. The top-down approach compares the utility’s production data with billing records to help determine a picture of the total system water losses. The bottom-up approach looks at utility management practices to determine exactly where water losses occur. For instance, some water losses can be attributed to line flushing, fire department usage, or street-cleaning operations. Other water losses can be attributed to meter errors, water theft, and pipe leakage due to excess pressure. The American Water Works Association (AWWA) publishes a comprehensive manual (Water Audits and Leak Detection M36) that can be used to develop a preliminary or comprehensive water audit. Water audits also can be used by utilities to understand the water usage characteristics of individual users. For instance, many larger utilities offer water audit services to their industrial, commercial, institutional (ICI) users to help their largest customers understand their water usage trends and detect system inefficiencies. Once created these audits can help customers save money through reduced water usage, and create good will between customers and utilities. Water expert Amy Vickers has written a comprehensive book on water conservation that includes water audit checklists for both residential and ICI customers (Vickers, 2001). Typically, a large part of the bottom up approach is a comprehensive leak detection program. Leak detection is a systematic search for leaks within a utility’s infrastructure. An effective program uses electronic equipment to locate leak sounds and pinpoint the exact location of leaks. Because leaks can develop at any time, these programs should be used on a regular basis. An effective program can yield several benefits. Generally, there is an immediate savings in pumping and treatment costs. Additionally, once leaks are discovered they can be scheduled for repair, eliminating the need for costly emergency repairs. A leak-detection program can also identify trends with faulty equipment. For example, one study found that most of the leaking fire hydrants in the city were purchased from the same manufacturer. Using this information, the utility manager developed a replacement plan for the leaking parts, and changed to the city’s specification for new hydrants (Wright, 2008). A leak detection program can generate significant savings in utility operating costs. One Florida study (Wright, 2008) uncovered four water main leaks that were responsible for 240,000 gallons per day in losses. Once the leaks were repaired, the water utility realized a reduction of $3,000 a month in water production costs, and a significant

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improvement in water main pressure. The higher water pressure also eliminated the need to replace a main that had previously failed to meet firefighting requirements. Another large leak detection/ remediation program in Georgia resulted in estimated annual savings of $650,000 for the utility (Pennington, 2007). Developing a leak detection program can be costly. Private contractors charge up to $120 per mile for leak detection services, and in-house programs require training and costly equipment. This can be problematic for smaller utilities with limited staff. But, because leaks can account for up to 10% or more of system losses, implementation costs can be often be quickly recovered through reduced production costs and increased system efficiency.

6. Implement Water Budgets and Rate Structures According to a recent study by the American Water Works Association (Mayer et al, 2008), “As populations increase and climate uncertainties place heightened demand and stresses on water systems, more utilities are seeking new tools for water conservation and drought response.” One effective management tool that utility managers can use to meet these challenges is a water budget rate structure (WBRS), which is a management system that uses a water budget together with an incentive-based rate structure. Utilities can develop water budgets for different classes of water customers, such as single-family residential, restaurants, etc., by reviewing historical records for those customers, and by analyzing water budgets that have been developed by other regional utilities, or by developing their own water budgets. The data are then used to establish a level of efficient water use or “targets” for the different types of customers. For instance, in Boulder, Colorado, a water budget of 7000 gallons per month is established for single-family. In an effort to curb landscape water usage (see landscaping section below), exterior water budgets are developed on a sliding scale where 15 gallons / square foot (gal/sf) are allotted for the first 5,000 sf of landscape area, 12 gal/sf for the next 9000 sf, and 10 gal/sf for areas that exceed 14,000 sf. Utilities can also use a similar approach to establish budgets for multi-family users and commercial, industrial, and institutional users. The second part of the WBRS usually makes use of an increasing block-rate pricing structure, by means of which water rates increase when customers exceed their water budget. This kind of program has several benefits. Water budgets help utility customers understand their usage patterns, and the sliding rate scale provides monetary incentives for customers to stay within their water budget. Utilities that have adopted a WBRS have also created substantial conservation savings. One study that reviewed several programs in California, reported up to a 37% reduction in water consumption. These reductions have stabilized demand and made it easier for utilities to set rates that can meet cost of

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service requirements, improving their revenue stability (Pekelney and Chesnutt, 1997). Reduced demand also generates savings in the form of reduced energy usage. A recent report (Mayer et al., 2008) provides a comprehensive look at how WBRS programs are created and managed. According to the study, implementation costs for a WBRS can vary widely. Generally, the existing customer billing system can be modified to meet the demands of a variable block rate structure, however software revisions may require outside expertise. Even with limited resources, utility staff can research historical trends, develop cost of service models, and review other systems’ operations to learn of the effectiveness of such programs, where they have been adopted. The AWWA study cites several programs that implemented WBRS programs in less than twelve months with existing staff resources. A recent report (Mayer et al., 2008) provides a comprehensive look at how WBRS programs are created and managed.

7. Create Financial Incentives for Water Customers Because the success of conservation programs is dependent upon the end user, many utilities have developed financial incentives such as rebates, vouchers, or incentives to encourage customers to change their water usage habits. Some examples include rebate programs for installing new water conserving fixtures, financial incentives for utilizing water efficient techniques like xeriscaping, and incentive-based rate structures (see discussion above). Landscaping Programs

For many Americans, the image of the ideal home includes a lush, well-maintained lawn. Unfortunately, the American obsession with green acres has significant water and energy consequences. According to the U.S. Geological Survey, 7.8 billion gallons of water are used every day, largely to irrigate our lawns and flower beds (Solley et al., 1995). Nationally, this accounts for approximately 30% of all residential water usage, and, in arid climates like Arizona, the numbers for landscape usage are much higher, sometimes accounting for 50-75% of total daily usage. These water demands often pose significant challenges to small utilities. During hot summer months, many water suppliers experience demand that is 1.5 to 3.0 times higher than the winter demand, and in smaller communities, this peak demand often approaches the operating capacity of the water system. Given these issues, several innovative utilities have focused their incentive efforts on reducing the outdoor water demand by creating landscape water conservation programs. These programs can generate several benefits. Vickers (2001) reports that the city of Albuquerque reduced outdoor water usage (which accounts for 50% of the city’s residential usage) by ten percent after mandating a water wise landscaping program that included rebates of $250 for reducing turf usage. Besides water usage and associated energy costs, a landscape water conservation program can also reduce the need for water infrastructure (storage, wells, pumping facilities), and reduce energy costs associated

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with pumping and treatment. These reductions can help stabilize a utility’s cost of service and improve long-term revenue stability. Several utilities offer landscaping incentive programs to help customers convert their existing water-hungry “turfed” landscapes to low-water-use xeriscapes. Here, the utility offers a monetary incentive to customers to convert irrigated turf landscapes to water-efficient “xeriscaping.” For instance, the City of Flagstaff (2008) turf replacement program offers rebates of up to $3,000 for replacing water-intensive landscapes with approved xeriscaping. The rebates are calculated on the square footage of turf removed from service. Other programs offer incentives for approved high-efficiency irrigation components such as rain-sensitive shutoff devices and drip irrigation systems. Toilet Replacement Programs

Toilets account for almost 27% of the water usage in an American single family home, using more water than any other household fixture or appliance. On average, each person uses a toilet 5.1 times per day, and each flush averages 3.48 gallons per flush, or gpf (Mayer et al., 1999). Toilets are also one of the main sources of leaks in a typical residence. Aging flapper valves, poorly sized replacement parts and malfunctioning contribute to a large piece of the water consumption pie. The AWWA estimates that up to 25% of American toilets leak, and these losses average 9.5 gallons per day per fixture (AWWA, 1993). As a result, many utilities have implemented toilet rebate or replacement programs to help conserve water. For instance, the city of Santa Monica, California, implemented a toilet rebate program in 1993 that effectively replaced 60% of older toilets with more efficient 1.6 gpf models. According to utility officials, this reduced water and sewage flows within in the city by 15%. These usage reductions resulted in the avoidance of significant capital improvement costs, and reduced energy usage for the city. Toilet replacement programs are generally sponsored by water utilities that use a credit or rebate to get their customers to update their fixtures. These programs vary widely. Some programs utilize an “incentive” fee program, where each customer is charged $2 a month to help fund the program, and the fee is removed once a customer’s toilet has been replaced. Other utilities offer a rebate of $50 - $150 to replace an old toilet. In Santa Fe, New Mexico, a recent law requires builders to replace an aging toilet in order to obtain a building permit for new construction. While federal law governs new toilet performance at 1.6 gpf, research indicates that toilet performance varies widely. As a result, utility managers should look to replace toilets with products that carry the EPA’s Water Sense logo.

Showerhead Exchange Program

According to the study “Residential End Uses of Water” (Mayer et al. 1999) showers account for almost 17% of a typical household’s water use. Because modern

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showerheads are more efficient than older programs, water providers can effectively reduce water consumption by establishing a showerhead exchange program. Users exchange their current showerheads for replacement fixtures (2.5 gallons per minute, or gpm, at 60 psi) provided by the utility. This ensures that water efficient showerheads are installed and inefficient fixtures are recycled. Recent research suggests that an effective showerhead exchange program can reduce household water consumption by between 5.7% and 10%, and, when fully implemented, a showerhead exchange program can save significant amounts of water (Vickers, 2001). The showerhead replacement program should also be marketed to non-residential users with high water usage profiles. These include hotels and motels, schools, dormitories, hospitals, gymnasiums, and athletic clubs. In one Massachusetts athletic facility, thirty-five high-flow showerheads were replaced with a low-flow model. The initial cost of the program was only $300; the annual savings from reductions in water, sewer and water heating energy costs was $3,300. The effective payback period for this program was one month (Vickers, 2001).

8. Adopt Water Efficient Ordinances and Codes Municipal ordinances and building codes are often one of the most cost-effective tools for accelerating water conservation within a community. Over the past several years, drought-like conditions in the Southwest have forced municipalities to draft ordinances that limit excessive exterior water usage. Faced with rapidly declining supplies, and explosive growth, the City of Las Vegas developed ordinances that limited lawn watering, banned the use of turf on new projects, and mandated water conservation techniques in all new building projects. These aggressive ordinances reduced water consumption in the City of Las Vegas by 20% in one year (JP Morgan, 2008). The City of Tucson requires the use of rain-shutoff devices (devices that turn off irrigation systems before and after rain events) on all new irrigation systems. Other cities, including Phoenix and Albuquerque, have created ordinances that mandate summer watering restrictions, and prohibit the wasteful use of water. Users who fail to comply with the ordinances are fined (Vickers, 2001). Building codes also can be used to help utilities conserve water. While building codes are often focused more on public safety than on water efficiency, they can usually be modified to mandate water conservation within a community. For instance, federal regulations stipulate that showerheads use less than 2.5 gallons per minute, but most building codes do not limit the number of showerheads that can be used in any one shower. This can be remedied by adopting a code variation that limits the number of showerheads per square foot of shower area. Other adaptations to the code allow for the usage of “waterless” urinals in public and commercial facilities (Pape, 2008). The “green” building movement can also be used to help utilities manage water demand. One of the areas of emphasis in most green building initiatives is the “efficient usage of

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water”. Cities that adopt green building requirements like the United States Green Building Council’s LEED initiative (see www.USGBC.org), can use these programs to mandate water efficiencies in new and existing buildings. The Alliance for Water Efficiency (AWE) maintains a website (www.allianceforwaterefficiency.org) that outlines several useful code variations and water ordinances.

9. Create Water Education Programs The effectiveness of any conservation program will usually depend upon a utility’s customers. For this reason, it is important to educate utility customers on “why” water conservation is important. Education can take many forms. The City of Albuquerque maintains a website (www.abcwua.org/content/view/70/60/) that shows customers how to create efficient rainwater gardens, and provides designs for drought-tolerant landscapes. In Australia, one utility uses an education program that features a water mascot, similar to those used at sporting events. The mascot appears at public events, shopping malls, and parades where he generates enthusiasm for the utility’s water education efforts. The water mascot also appears at grade schools where he introduces the water conservation program to young students. According to a Texas study, school education programs can be particularly effective at gaining the public’s trust for new conservation programs. Here, water conservation is introduced to the students, who, in turn, introduce the concepts to their parents. The Texas study suggests creating an advisory board of educators and utility operators, who can assist in choosing and developing a curriculum. One curriculum features a science experiment where students are asked to measure the flows of their showers, toilets, and faucets. When the data are returned, students are given low-flow faucet aerators and showerheads, which they then use to retrofit their homes. In the final part of the project, students determine the water savings for the house. In this case, a science project not only trains students and parents about the economics of water conservation, but it also helps reduce the water usage with the local utility (Texas Water Development Board, 2004). One resource for Arizona educators is Project WET (Water Education for Teachers) Project WET Arizona, is a state affiliate of National Project Wet, which was developed by the U.S. Bureau of Reclamation. The University of Arizona's Water Resources Research Center and the College of Agriculture Cooperative Extension 4-H Youth Development jointly administer the program. Project WET provides water education resources and assistance to educators, who are broadly defined as public and private school teachers, 4-H leaders, Boy and Girl Scout leaders and others in teaching or leadership positions. WET resources are appropriate for all ages, although the project's priority is to provide teaching aides for K-12. Much of the educational information specifically relates to Arizona, including water conservation, water pollution, and water rights.

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System Design and Engineering

10. Review System Plans, Specifications, and Records Plant operators and managers who are well-acquainted with the design and the intended operation, as well as with the current and historical operation of their facility, are best situated when it comes to evaluating how their systems are performing and how those systems might better perform if improvements or changes are made. If new management or operators seek to gain familiarity with the system(s) for which they are responsible, consider inviting a ‘circuit rider’ from the Arizona Small Utilities Association (ASUA), which can provide:

On-site Technical Assistance, which may include, but not be limited to: development of operational and equipment preventive maintenance plans, identification of operational deficiencies, corrective maintenance plans, system enhancement project planning and financing, and water quality sampling for analysis.

Training: organized by certified water and wastewater professionals with

qualified trainers having expertise and knowledge of the water and wastewater industry.

Source Water Protection: ASUA professionals work with water systems to

develop Wellhead Protection Programs (WHPs).

Regulatory and Legislative Advocacy: With the help of member systems, ASUA develops positions on legislative and rule-making activities. ASUA legislative representatives will work with Congress, the state legislature and state departments to communicate positions.

11. Take Measurements, Evaluate the Data, Make Decisions Water and wastewater system operators and managers need to be able to measure, or have access to individuals or equipment that can measure: pressure; elevation; flow; electrical voltage and current, or power; temperature; rotational pump speed. These measurements are necessary to assess the present operating condition of systems and system elements, and to provide answers to questions such as:

what is the load factor (see AWWA, 2003) for a given piece of equipment? what is the average inflow of influent?

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how does potable water production vary over the course of an hour, a day, a month, or a year?

what is the energy loss between two given points of a water / wastewater system? how much energy is a pump adding to a flow? Where on the pump curve is a given pump operating and what is the efficiency of

that pump’s operation? Is a motor operating efficiently?

Also, these measurements provide the data that allow operators and managers to assess whether a given change or improvement has had the intended effect. Guidance on open-channel flow measurements is available from the U.S. Bureau of Reclamation (USBR, 2001). For pressurized systems, there is not a single guide that covers all possibilities, however, manufacturers of power, flow, level and pressure meters / transducers / sensors typically provide their own guidance. While the above types of measurements are the most common in water and wastewater systems, on occasion, other measurements (see Sullivan et al., 2004) may be useful – particularly with regard to evaluating the energy consumption and energy efficiency of equipment and machinery: oil analysis; temperature measurement (for example, using thermal imaging); vibration measurement and analysis. When deciding to collect data, consider that:

Good data are better than no data; No data may be better than bad data; Too much information can overwhelm an organization’s ability to manage the

data; There are expenses associated with collecting and managing data, so plan

strategically to collect useful data and to archive that data for future needs.

12. Evaluate Different Available Water Sources and Their Costs A recent study (Olsen & Larson, 2003) indicated that the energy cost associated with groundwater production and treatment is typically greater than for surface water production and treatment. In the cited study, which considers systems in the Madison, Wisconsin area, energy costs are estimated at 1.3 kWh/kgal for surface water and 1.7 kWh/kgal for groundwater. While groundwater treatment costs are often relatively low, the energy cost for lifting water from considerable depths to the surface is not. An economic analysis to decide between ground or surface water sources requires consideration not only of energy costs, but must also take into account any necessary infrastructure, such as for water treatment, water rights or procurement, and O&M costs. This sort of analysis also must consider issues such as security, whether the supply can be sustained (drought and other impacts), etc., and these issues may well trump energy costs.

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13. Reduce Leakage through Pressure Management Consider reducing the water system pressure when possible to reduce leakage and to reduce stress on distribution system and user piping. There may be additional opportunities to reduce pressure during periods of lower demand, which will be at night for most systems. With pressure management, not only will leakage be reduced, but system energy requirements also may be reduced, depending on how pressure is reduced. If pressure reducing valves (PRVs) are used to reduce pressure, there will be no energy savings. However, if pumps operated by variable frequency drives (VFDs) are used to manage pressure, there will be energy savings. A series of relevant articles, including a case study of one Australian water distribution system pressure management, are provided on the Pacific Water Efficiency website. In one such article (Mistry), the author reports that:

Basically, a higher pressure will result in a greater frequency of bursts and more water lost through leaks and burst pipes. Installation of computerized, flow-sensitive pressure control valves or the retrofitting of electronics on to existing pressure reducing valves can be used to reduce unnecessary high nighttime pressures and minimize the problem of fluctuations in pressure which weaken pipe systems and reduces their asset life.

14. Reduce Energy Losses in Pumps & Fans Pumping systems use substantial amounts of energy. For instance, an Electric Power Research Institute study (EPRI, 1996) found that with groundwater based water supply systems, the vast majority (nearly 99%) of energy goes for well pumping and booster pumping. With surface-water-based water supply systems, most (in excess of 95%) of the energy used is for raw and treated water pumping. There are fairly standard methods and technologies for assessing the efficiency and operation of pumps, and software is available for evaluating the effectiveness of proposed improvements. The objective is to reduce hydraulic energy losses in the pump and electrical energy losses in the driver (motor) and to maximize overall system efficiency in the process. The closer the match between the power input to the pump and the power transferred to the water, the greater the efficiency. Two common strategies are to operate constant-speed pumps as near as possible to their point of maximum efficiency, and to utilize variable-speed pumping to achieve the same objective when the flow or pressure that must be supplied by the pump varies considerably during the period(s) of pump operation.

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Best energy management practices for pumps (USDOE, 2008) are a series of tip sheets have been detailed by the U.S. Department of Energy’s Energy Efficiency and Renewable Energy program, which has also prepared a pump energy sourcebook (USDOE, 2006) that addresses improving pump efficiency, and a fan energy sourcebook (USDOE, 2003) that addresses fan efficiency. Additionally, pump energy efficiency (USDOE, 2008a) and fan energy efficiency (USDOE, 2008b) assessment software are available from the Department of Energy. The trade magazine Waterworld has a monthly column, Pump Tips & Techniques that offers guidance for operators and managers (Budris, 2008).

15. Reduce Friction Losses in Production Wells As noted previously lifting and pressurizing groundwater requires considerable energy. Depending on design and operating conditions, there may be considerable energy losses incurred as water is extracted from aquifer storage. Related best practices include design for high efficiency extraction, with consideration given to the aquifer, the gravel pack and the well screen, and through maintenance or rehabilitation to restore efficiency lost due to normal aging processes (Drake, 2008; McGinnis, 2008). The commonly used measure of well (not pump) efficiency is specific capacity, which is the volume of water produced (gallons) divided by drawdown (feet). The larger the volume that can be produced at a given drawdown, the greater the well efficiency; as drawdown increases, the required lift will increase, as will the required energy input. On a parallel track, pumping systems for water production wells, such as vertical turbines with the electrical motor at the surface, or submersible pump and motor configurations, need to be designed, operated, and maintained for maximum efficiency.

16. Reduce Friction Losses in Valves Valves of all types (check, stop, regulating, control, altitude, etc.) have the proven potential to cause energy losses in water systems. This is especially a concern for systems that are pressurized by pumps. Even when valves are operating correctly, the energy loss associated with one valve type could be ten times that of another valve. If your system has only a few valves, this will not be significant. However, if a system has tens or hundreds of valves, the associated energy costs can be significant. Valves that are operating in a partially closed position can give rise to large hydraulic energy losses; if pumps pressurize the system, then large electrical energy losses will be incurred.

17. Reduce Friction Losses in Pipes It takes energy, supplied either by pumps or by elevated storage, to overcome pipe friction in transmission and distribution system piping. Since frictional resistance to the flow of water is present in any pipe, all one can do is minimize friction losses. This is an optimization problem that requires consideration of the value of existing pipe runs, the

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cost of rehabilitation or replacement, and the tradeoff between projected energy cost reduction(s) and the costs of improvements. Plastic pipe friction losses are relatively low in new pipe and can be treated as fairly constant over time. For metal pipes, no matter whether in a water transmission or water distribution system, friction losses will generally increase over time. The growth of tubercules in many types of metal pipe both increases friction and reduces the area of pipe available for transmitting water. Best practices for reducing pipe friction consist mainly of pipe cleaning (AWWA, 2003), pipe lining (Muenchmeyer, 2008), and pipe replacement (with or without an increase in pipe diameter).

18. Adequately Ventilate or Sunshield in Warm Weather Electrical resistance increases with temperature. As a result, exterior motors should be shielded from the sun. Motors at wellheads need to remain accessible for repair or removal and shields need to be removable.

19. Use Gravity to Move Water Most hydraulic systems provide for the exchange of energy between elevation, or gravitational potential energy, velocity, or kinetic energy, and energy of pressurization. In some operations, water flows from a higher to a lower elevation under the action of gravity and then, due to a design flaw or another reason, the water must be returned to a higher elevation with a pump. The objective of this practice is to utilize gravitational potential energy wherever possible, rather than pumps, to promote the flow of water from one location to another.

20. Automate System Operation The utilization of Supervisory Control and Data Acquisition (SCADA) systems is widespread in larger water and wastewater utilities but not so in smaller rural systems. SCADA systems allow not only for monitoring, but for control and more sophisticated automated decision making and real-time adjustment of pumping rates, process parameters, valves, etc. A recent overview is provided by Schroeder et al. (2008).

21. Generate High-Quality WWTP Effluent Adequately treated wastewater (effluent) is a water resource of increasing value. If treatment is to sufficiently high quality, which vary across the nation but are generally uniform across a given state, such as Arizona, the effluent can be reused for irrigation, industrial applications, groundwater recharge, power plant cooling water, etc. The wastewater treatment process(es) in use, or selected as part of redesign, or for design of a new facility, can have a great influence on effluent quality. As an example, a membrane bioreactor (MBR) process, in comparison to an activated sludge process, may offer considerable advantage in removing endocrine disrupting contaminants (presently unregulated) that exist in most WWTP influent streams (Arizona Water Resource, 2008).

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Mankato, Minnesota’s new wastewater reclamation facility was recognized by Minnesota APWA (American Public Works Association) for its high-quality effluent, which will be used for power plant cooling water at the nearby Calpine power plant (Water World, 2008). The new plant was constructed by means of a public-private partnership amongst the City of Mankato, California-based Calpine, and the Minnesota Pollution Control Agency (MPCA).

22. Consider Hydroxyl Ion Fog for Wastewater Odor Control A relatively new technology is the hydroxyl ion fog odor control system by Vapex. The hydroxyl ion fog system offers the potential for reduced energy and capital costs where odor control is routinely required: headworks, scrubbers, holding tanks, lift. stations, wet wells, etc. The hydroxyl ion fog reacts with odorous hydrogen sulfide gas, reduces the corrosion associated with the gas, and breaks down grease. The system can be considered as an alternative, or supplement to carbon, biological, and chemical scrubbers.

Operations and Maintenance

23. Manage Air in Pressurized Water and Wastewater Systems

The presence of air in pressurized water or wastewater systems can cause excessive energy consumption in pumped systems, including possible damage due to hydraulic transients (water hammer). The underlying cause is a loss in cross-sectional area of flow with accompanying flow reduction and increased friction losses.

Pressure pipe runs need to be evaluated by an engineer with expertise in water transmission. Common remedies include strategic placement of air release valves.

24. Utilize Off-Peak Power Usage Strategies Electrical power demand by residential, commercial, institutional, and industrial users varies considerably over the course of a 24-hour day. Furthermore, the demand over a 24-hour period will vary according to the season. Electrical power providers need to respond to this variable demand and their expenses, and consequently, the cost of purchasing power, is usually greatest when demand is at its peak. As a result, the rate for electrical power, particularly for users with large electrical demands, will vary, depending if the use is on-peak or off-peak. For users with significant electrical power needs, often there are cost advantages to shifting power use from on-peak to off-peak periods. The threshold for electrical power pricing, according to such a program, is different for each electrical power provider.

With water treatment, raw / source groundwater supply pumps are used to lift water from wells to the surface and into storage, often with minimal treatment. In small systems,

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these well pumps usually operate intermittently. It may be advantageous to operate the well pumps at off-peak periods when electricity is less expensive to purchase.

The North Liberty, Iowa, water utility saves energy and reduces expenses with off-peak groundwater pumping into ground storage, in conjunction with variable frequency drive (VFD) pumps to move water through treatment and into elevated storage (Iowa Association of Municipal Utilities, Year Unknown A). In this instance, a key requirement is adequate storage, so that pumps can be operated during the off-peak time period. Otherwise, the pumps would have to operate in synchronization with demand, regardless of power pricing. The water utility department in the City of Fresno has several hundred well pumps. Fresno uses a SCADA system to monitor and control pumps for operation, to the greatest extent possible, at times when power costs for each particular pump location is at a minimum (City of Fresno, 2008).

25. Optimize Treatment Processes to Reduce Water and Energy Consumption

Poor water quality may necessitate treatment that has significant associated energy costs. This is certainly the case for wastewater, but it is also true for potable water. Certain water treatment processes, for example, reverse osmosis (RO), consume both energy and water. Each treatment process generates a waste stream, which could be small, as in the solid waste generated from water disinfection using bottled sodium hypochlorite, or it could be much more significant, as in sludge generation at a WWTP. While laws and regulations typically dictate the allowable water quality for treated potable water or wastewater, e.g., the Safe Drinking Water Act (SDWA) and Clean Water Act (CWA), compliance with the laws, regulations, and standards often requires one or more additional processes. These processes not only have capital and O&M costs, but they also require energy, and they may require a water input. Blending water supplies may, in some instances such as meeting the SDWA arsenic standard, allow a water utility to reduce or eliminate the treatment necessary to meet regulatory criteria. Alternative processes may consume less energy; however, one needs to take into account all costs, not only capital or energy costs.

26. Coordinate Water Production / Delivery with Treatment Process Capacity

High rates of raw water production / delivery for short periods of time may result in over-sized water treatment infrastructure with correspondingly high energy use, embedded energy use, operations and maintenance expenses, etc. For example, if a new arsenic

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treatment system has to be sized for 300 gpm water well production and the well only runs for a few hours a day, it may be prudent to downsize the production well pump and go with a lower-capacity treatment system, presumably one that is scalable as demand grows over time. Wastewater facilitiesthat have no little or no storage at the front-end and are sized primarily for peak periods of inflow, tend to have processes and equipment that must be operated under peak inflow conditions, even during periods of off-peak inflow.

27. Retrofit Facilities with Energy-Efficient Lighting A good general reference, extensively quoted here, is: Energy Reduction Techniques for Small and Medium Water and Wastewater Systems (Florida Rural Water Association, 2007). Proven practices include:

Utilize natural lighting when and where possible (need to consider HVAC costs and benefits as well);

Use high efficiency ballasts for fluorescent lighting (retrofit/new purchase); Use high-reflectivity reflectors (retrofit/new purchase); Replace incandescent bulbs with compact fluorescent bulbs (use same fixture); Consider high or low pressure sodium over incandescent bulbs; Consider low pressure sodium over high pressure sodium; Consider LED lighting, which has the best efficiency of all lighting; Consider, time-based, occupancy-based, or photo-cell-based lighting controls; Consider task lighting instead of overhead lighting; For outdoor lighting, make sure lighting is directed onto the ground or task area

instead of up into the sky.

28. UV Disinfection Systems Best Practices Ultraviolet light-based effluent disinfection currently is not common in rural wastewater systems. However, these systems are increasingly used, and some attention to their operation and maintenance is warranted. A first strategy is to reduce the electrical energy lost (as heat) in low efficiency ballasts, which are electrical devices that limit current flow through the UV lamps. Implementation of this practice will require evaluation of the existing system and ballasts, and consultation with the manufacturer. For an overview, consult Lupal (2001). The Princeton, Indiana WWTP recently has implemented the use of high-efficiency ballasts (Princeton, 2008). The quartz sleeves that enclose the UV lamps foul over time and there is an accompanying decline in UV intensity, with reduced disinfection. Automated systems will assess UV light intensity attenuation over time, but that is no substitute for regular visual inspection of operating conditions.

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Larger UV disinfection systems with multiple flow channels and banks of UV disinfection lamps may be candidates for modified operation by means of which flows pass through a single channel during periods of low flow, reducing the need for simultaneous and energy-wasting operation of lamp banks in two or more channels. Philips and Fan (2005) provide a case study of implementation at the UC Davis WWTP, where it was found that annual UV system energy dropped by nearly 25%; bulb lives were extended by a similar amount; and, payback, based on energy savings alone, took only four years.

29. Increase Electrical Motor Efficiency This a widely-used practice and consists primarily of replacing lower efficiency motors with higher-efficiency models. This reduces electrical losses in the driver. It may be cost-effective to not replace motors until they are near the end of their design life. If appropriate, single-speed motor operations should be upgraded to variable-frequency drives. Additionally, it may be feasible to switch from single-phase to three-phase power. Three-phase motors are generally more efficient in their use of electrical power. Finally, motors should be evaluated for inefficient operation due to miscoupling / misalignment or due to poor mounting. Electrical losses are reduced because electrical energy will no longer be converted to unnecessary, potentially damaging, and energy-wasting mechanical vibration (see practice 11).

30. Operations and Maintenance (O&M) Guides and Education & Training When new systems or components are procured, specify that the designer or supplier is to provide written and illustrated operations and maintenance (O&M) guides and on-site O&M training, possibly with a requirement for professional videography of the initial on-site training. These reference and training materials, if used and followed, will help to promote O&M consistent with the intent of the designer or vendor. Anticipate that, over time, seasoned and knowledgeable operators may improve and amend O&M practices. Additionally, overall education and training for operators is essential so that they can understand utility policies, management and operations, be aware of energy supplies and uses and costs and understand the basis for successful application of best practices for water and energy conservation (Cantwell, 2008).

Renewable Energy Because water and wastewater systems have regular and continuous power demands, there are excellent opportunities for using renewable energy sources. Renewable energy sources such as photovoltaic panels and wind turbines can be used to help meet day-to-day energy needs. Given the significant recent and ongoing investment in renewable

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energy, technologies are becoming more efficient and cost effective. In Arizona, where there are ample sun and significant wind resources, renewable systems can be effective at reducing expensive peak power demand placed on conventional providers. Other renewable sources include sludge digesters that produce methane. The methane is captured and used to power a gas engine generator or a micro-turbine system. These systems utilize the methane gas produced in anaerobic treatment processes, reducing the GHG emissions of the wastewater treatment plant. To date, these kinds of systems have been limited to plants that exceed a threshold of 5-10 million gallons per day (Mgd).

31. Wind Energy Wind has long been used to help pump, distribute and treat water. In the early 20th century, the development of the steel windmill and reciprocating pump provided water to farms, ranches, and railroads in the rapidly developing American west. This technology is still used to pump water worldwide. According to a report from the National Renewable Energy Laboratory (NREL), there are over one million windmills in the United States, Argentina, and Australia alone (Argaw, 2001). However, wind-powered mechanical pumps have limitations. Because of their reciprocating pump design, these pumps need to be installed directly over a well head. This poses problems because groundwater is often tapped in low-lying valleys, and these locations are not usually optimal for available wind energy. Given the above location constraints on windmill / reciprocating pump installations, an electric wind turbine offers greater versatility. These turbines are designed to generate electricity (AC or DC) that can be used to operate a variety of electrical devices. Wind power can be used effectively to power pump motors, fans, lights, controls, and convenience power for small utilities. In pumping operations, the turbine can be coupled with an AC motor, which then drives the pump at varying speeds. This eliminates the need for costly batteries and inverters. Because electricity is easily transported, the turbine can also be placed in locations that will allow for the most efficient wind energy harvesting. Electrical wind pumps are twice as efficient as traditional windmills and are often a cost-effective alternative to traditional power supplies (Argaw, 2001). In relatively recent applications, wind-energized aeration of both potable water reservoirs and wastewater lagoons and ponds has been implemented and evaluated in a range of settings (Horan et al., 2006; Anonymous, 2008; Brzozowski, 2008).

32. Solar Energy Given the escalating cost of energy, several large municipalities have started to integrate solar power into their operations. The Alvarado water treatment plant in San Diego (120

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Mgd) recently installed a solar power system that saves the utility nearly $70,000 in costs annually. Many smaller municipalities will have difficulty funding the upfront costs associated with renewable systems. In this case, it may make sense to utilize a “power purchase agreement.” Here, a development partner acts as an intermediary between the municipality and its power utility. The development group provides all of the upfront costs, design, installation and financing costs required for the project. In turn, the municipality signs a power-purchase agreement that allows them to buy power at a specified rate for 15 to 20 years. Generally, this fixed rate can be 15% to 25% less than the utility’s typical cost per kilowatt hour. The advantage here is that utilities can lock in power rates for an extended period at a reduced cost. As power prices are escalating at an average of 5% a year, a fixed rate can substantially reduce future costs (Public Works, July 2008). The most cost-effective method is to install a renewable energy system behind the electric utility’s meter at the site. In this way, the water or wastewater utility can use the energy produced to augment power usage without a contractual agreement from the electric utility. This is particularly appropriate for small renewable systems like wind turbines and smaller photo-voltaic (PV) systems. If possible, it is best to size the renewable system to provide 75% of the power requirement of the facility. This allows the water or wastewater utility to generate a significant fraction of its power requirements, but still allows for a backup connection to the electric utility. If the renewable energy is installed in front of the electric meter, then a power purchase agreement will have to be negotiated with the local electric utility. In this case, the green credits are sold to the local electric utility, and a power agreement is established between user and provider. Again, because the rate is fixed, the inflation risk is reduced. Another idea is to form a collective that can pool small users to purchase bulk power from utility groups. Small collectives may also be able to pool enough small projects to

enerate the interest of a solar investment partnership. g

Acknowledgments This project was financially supported by the Arizona Water Institute (AWI) and Grand Canyon National Park. We would like to acknowledge Bill Reed of ADEQ; Chuck Graf of ADEQ and AWI; Vern Camp of the Arizona Small Utilities Association; Tom Mossinger of Carollo Engineers; Guy Carpenter of HDR Engineers; and, Barbara Lockwood of Arizona Public Service (APS).

References Anonymous, 2008, Catching Wind for Clean Water, Water and Wastewater News, August 1, 2008.

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Argaw, N. 2003. Renewable Energy in Water and Wastewater Treatment Applications. National Renewable Energy Laboratory (NREL). Golden, Colorado. http://www.nrel.gov/docs/fy03osti/30383.pdf Arizona Climate Change Advisory Group. 2006. Climate Change Action Plan (Appendix D: Greenhouse Gas Emissions Inventory and Reference Case Projections 1990-2020). http://www.westcarb.org/Phoenix_pdfs/finalpdfs-11-08-06/14-Domsky_IMD.pdf Arizona Water Resource, September-October 2008. Study Looks at Wastewater Treatment Methods of Removing Estrogen, Volume 17, Number 1. http://www.ag.arizona.edu/azwater/awr/septoct08/d3f18b0d-7f00-0101-0097-9f67df0fe598.html AWWA. 1993. The Water Conservation Manager’s Guide to Residential Retrofits. American Water Works Association, Denver, Colorado. http://www.awwa.org/index.cfm AWWA. 1999. Water Audits and Loss Control Programs, American Water Works Association, Manual of Supply Practices, Manual M36, American Water Works Association, Denver, CO. A new (3rd) edition of this manual is due out in 2009. http://www.awwa.org/index.cfm AWWA. 2000. Principles of Water Rates, Fees, and Charges (Manual M1), Fifth Edition, American Water Works Association, Denver, CO. AWWA. 2003, Principles and Practices of Water Supply Operations: Water Transmission and Distribution, Third Edition, American Water Works Association, Denver, CO. AWWA RF. 2003. Best Practices for Energy Management. American Water Works Association Research Foundation. John Jacobs, Thomas Kerestes and W.F. Riddle, EMA, Inc., St. Paul, MN. Barry, J.A. 2007. WATERGY: Energy and Water Efficiency in Municipal Water Supply and Wastewater Treatment. The Alliance to Save Energy. http://www.watergy.net/resources/publications/watergy.pdf Brand and Wilt, 2003, Backwash Water Treatment & Recycle in Ruidoso, NM. “A Tale of Two Watersheds”, proceedings of the 2003 Joint Annual RMWEA / RMSAWWA Conference in Casper, Wyoming. http://www.rmwea.org/tech_papers/water/watershed/AWWA%20Present%20Paper%20-%20Ruidoso%20BW%20Recycle-%209-11-AM%20DDB.doc Brzozowski, C., 2008, Less is More, Onsite Water Treatment, January/February 2008 Budris, A. 2008, Pump Tips & Techniques. Waterworld. http://ww.pennnet.com/

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Burton Environmental Engineering, RCG/Hagler, Bailly, Inc, Metcalf & Eddy, and Electric Power Research Institute (EPRI). 1993. Water and Wastewater Industries: Characteristics and DSM opportunities. Palo Alto, CA. Cantwell, J.C. 2008. Learn Basics of Energy Efficiency. Opflow, December issue. American Water Works Assocation. City of Flagstaff, 2008, Turf Replacement Program. http://www.flagstaff.az.gov/index.asp?NID=846 City of Fresno, 2008. http://www.fresno.gov/Government/DepartmentDirectory/PublicUtilities/Watermanagement/SCADASystemandInformationControl.htm Cohen, R., Nelson, B., and Wolff, G. 2004. Energy Down the Drain. The Hidden Costs of California’s Water Supply. Natural Resources Defense Council. Oakland, California. http://www.nrdc.org/water/conservation/edrain/edrain.pdf deMonsabert, S., and Liner, B. L. 1996. WATERGY: A Water and Energy Conservation Model for Federal Facilities, presented at CONSERV’96, Orlando, FL. http://www1.eere.energy.gov/femp/pdfs/watergy_manual.pdf Dones, R., Heck, T., and Hirschberg, S. 2003. Greenhouse Gas Emissions from Energy Systems: Comparison and Overview, PSI Annual Report 2003 Annex IV, Paul Scherrer Institute, Villigen, Switzerland. http://gabe.web.psi.ch/pdfs/Annex_IV_Dones_et_al_2003.pdf Drake, C. W. 2008. How to Improve Well Efficiency and Well Yield to Save Money, Proceedings of the 2008 Meeting of the American Institute of Professional Geologists, Arizona Hydrological Society, and 3rd International Professional Geology Conference, Flagstaff, Arizona, USA. http://www.aipg.org/2008/technical_sessions.htm Elliott, T., Zeier, B., Xagoraraki, I., and Harrington, G. W. 2003. Energy Use at Wisconsin’s Drinking Water Facilities, Energy Center of Wisconsin, Madison, WI. http://www.ecw.org/prod/222-1.pdf Elliott, T. 2003. Energy Saving Opportunities for Wastewater Facilities – A Review. http://www.ecw.org/ecwresults/221-1.pdf EPRI (Electric Power Research Institute). 1996. Water and Wastewater Industries: Characteristics and Energy Management Opportunities, Report CR-106941. http://epri.com/ EPRI. 1999. Energy Audit Manual for Water/Wastewater Facilities. Electrical Power Research Institute, Palo Alto, CA. http://www.cee1.org/ind/mot-sys/ww/epri-audit.pdf

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EPRI. 2002. Water & Sustainability (Volume 4): U.S. Electricity Consumption for Water Supply & Treatment - The Next Half Century. Electric Power Research Institute, Palo Alto, CA. http://mydocs.epri.com/docs/public/000000000001006787.pdf Florida Rural Water Association. 2007. Energy Reduction Techniques for Small and Medium Water and Wastewater Systems. Draft of Nov 28, 2007. http://www.frwa.net/Manuals/EnergyReductionDocument112507.pdf(Much of the material in this reference is from EPRI’s Energy Audit Manual for Water and Wastewater Facilities, Watergy’s, Energy Efficiency in Municipal Water Supply and Wastewater Treatment, and Pacific Gas and Electric’s Baseline Study for Efficient Wastewater Treatment Facilities and Baseline Study for Efficient Water Treatment Facilities.) Gelt, J 2002. Arizona Rural Water Issues Attracting Attention. Arroyo, v 11, no 1, pages 1-12. http://ag.arizona.edu/AZWATER/arroyo/webarroyo2.pdf Horan, N. J., Salih A., and Walkinshaw T., 2006, Wind-aerated lagoons for sustainable treatment of wastewaters from small communities, Water and Environment Journal Volume 20 Issue 4, Pages 265 – 270. Iowa Association of Municipal Utilities. Year Unknown A. Cedar Rapids Water Utility Energy Efficiency Management Program – Meeting the Demands of Industrial and Residential/Commercial Customers. http://www.iamu.org/services/electric/resources/appa_deed/CR_Water_Department.pdf

Iowa Association of Municipal Utilities, Year Unknown B. North Liberty Water Utility Saves Energy and Money with Off-Peak Pumping and VSPs. http://www.iamu.org/services/electric/resources/appa_deed/North_Liberty.pdf JP Morgan. 2008. Watching Water – A Guide to Evaluating Corporate Risks in a Thirsty World. JP Morgan Global Equities Report. April 1, 2008. http://www.wri.org/publication/watching-water Lupal, M. 2001, UV Ballasts Enter Electronic Age, Water Technology Magazine. see: http://www.prudentialtechgy.com/data/UVballastsenterelectronicage-artricle-ML.pdf Kunkel, G., et al. 2003. Water Loss Control Committee Report: Applying Worldwide Best Management Practices in Water Loss Control. Journal AWWA, 95:8:65. http://www.mhprofessional.com/product.php?isbn=0071499180 Mayer, P., De Oreo, W. Chesnutt, T, Summers L. 2008. Water Budgets and Rate Structures: Innovative Management Tools. Journal of the American Water Works Association. Volume 100, No. 5. http://www.iwaponline.com/wio/2008/09/wio200809AF91205F.htm Mayer, P.W., W.B. DeOreo, E.M. Opitz, J.C. Kiefer, W.Y. Davis, B. Dziegielewski, and J.O. Nelson. 1999. Residential End Uses of Water. American Water Works Research

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Foundation: Denver, Colorado. McGinnis, K. 2008. Water Well Performance: The Economic Basis for Operation, Well Rehabilitation and Maintenance Decisions, American Groundwater Trust Workshop, Phoenix, Arizona, February 7, 20008. http://www.agwt.org/events/2008/08AZWD_PresenterBios.htm Mistry, Pank. Pressure Management to Reduce Water Demand and Leakage. http://www.pacificwaterefficiency.com/FileLibrary/pressuremanreducewd.pdf Muenchmeyer, G.P. 2008. Renewal of Potable Water Mains Next Frontier for Trenchless Technology, WaterWorld. http://ww.pennnet.com/display_article/326069/41/ARTCL/none/none/1/Renewal-of-Potable-Water-Mains,-Next-Frontier-for-Trenchless-Technology/ Olsen, S., and Larson, A. 2003. Opportunities and Barriers in Madison, Wisconsin: Understanding Process Energy Use in a Large Municipal Water Utility, Proceedings of ACEEE Summer Study on Energy Efficiency in Industry 2003 Sustainability and Industry: Increasing Energy Efficiency and Reducing Emissions. http://www.cee1.org/ind/mot-sys/ww/mge2.pdf Pape, T. 2008. Plumbing Codes and Water Efficiency: What’s a Water Utility to Do? Journal of the American Water Works Association. May 2008. Volume 100, No. 5. http://www.awwa.org/publications/AWWAJournalArticle.cfm?itemnumber=35720 Pekelney, D. and Chesnutt, T. 1997. Landscape Water Conservation Programs: Evaluation of Water Budget Based Rate Structures, Proceedings. B (1998):1. Report prepared for the Metropolitan Water District of Orange County. A&N Technical Services Inc., Encinitas, Ca. Phillips, D. L. and Fan, M. M. 2005. Aeration Control Using Continuous Dissolved Oxygen Monitoring in an Activated Sludge Wastewater Treatment Process. Proceedings of the 2005 WEFTEC Conference. http://www.owue.water.ca.gov/recycle/docs/WEFTEC05_Session19_Phillips.pdf Phillips, D. L., and Fan, M. M. 2005. Automated Channel Routing to Reduce Energy Use in Wastewater UV Disinfection Systems http://www.owue.water.ca.gov/recycle/docs/UCD_UV_Disinfection_Energy_Reduction.pdf Princeton. 2008. Princeton Wastewater Treatment Plant – Post Treatment UV Disinfection. http://princeton-indiana.com/wastewater/pages/post-treatment/uv-disinfection.html

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Schroeder, D., Serjeantson, B., McKinney, S. 2008. Enhance Operations with SCADA Power, Opflow/AWWA, V. 34 No. 3 (March). http://www.awwa.org/publications/OpFlowArticle.cfm?itemnumber=34064 Solley, W. Pierce, R., and Perlman, H. 1998. Estimated Use of Water in the United States in 1995, U.S. Geological Survey Circular 1200. U.S. Department of Interior. USGS, Reston, Va. Sturman, J., Ho, G. E., and Mathew, K. 2004. Water Auditing and Water Conservation, London: IWA Publishing. http://www.iwapublishing.com/template.cfm?name=isbn1900222523 Sullivan, G. P., Pugh, R., Melendez, A. P., and Hunt, W. D. 2004. Operations & Maintenance Best Practices: A Guide to Achieving Operational Efficiency, Pacific Northwest National Laboratory for the Federal Energy Management Program of the U.S. Department of Energy. http://www1.eere.energy.gov/femp/pdfs/OandM.pdf Texas Water Development Board. 2004. Water Conservation Best Practices Guide. Report 362. Texas Water Development Board. Austin, Texas. http://www.twdb.state.tx.us/assistance/conservation/TaskForceDocs/WCITFBMPGuide.pdf Torcellini, P. Long, N., and Judkoff, R. 2003, Consumptive Water Use for U.S. Power Production, Report NREL/TP-550-33905, National Renewable Energy Laboratory, Golden, Colorado. http://www.nrel.gov/docs/fy04osti/33905.pdf USBR. 2001. Water Measurement Manual. U.S. Bureau of Reclamation. http://www.usbr.gov/pmts/hydraulics_lab/pubs/manuals/WMM_3rd_2001.pdf USDOE. 2008. Best Practices Pumping Tip Sheets. U.S. Department of Energy. http://www1.eere.energy.gov/industry/bestpractices/tip_sheets_pumps.html USDOE. 2008a. Fan System Assessment Tool (FSAT). U.S. Department of Energy. http://www1.eere.energy.gov/industry/bestpractices/software.html USDOE. 2008b. Pump System Assessment Tool (PSAT). U.S. Department of Energy. http://www1.eere.energy.gov/industry/bestpractices/software.html USDOE. 2006. Improving Pumping System Performance. U.S. Department of Energy. http://www1.eere.energy.gov/industry/bestpractices/pdfs/pump.pdf. USDOE. 2003. Improving Fan System Performance. U.S. Department of Energy. http://www1.eere.energy.gov/industry/bestpractices/pdfs/fan_sourcebook.pdf. Vickers, A. 2001. Water Use and Conservation. Waterplow Press. Amherst, Mass. (Pages 140-141.)

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Water World. 2008. Water reclamation facility recognized by Minnesota APWA. http://ww.pennnet.com/display_article/317083/41/ARCHI/none/INDUS/1/Water-reclamation-facility-recognized-by-Minnesota-APWA/ Westerhoff, G.P., Gale, D., Gilbert, J.B., Haskins, S.A., and Reiter, P.D. 2003. The Evolving Water Utility: Pathways to Higher Performance. American Water Works Association. Denver, CO. Wisconsin. 2002. Roadmap for the Wisconsin Municipal Water and Wastewater Industry, State of Wisconsin Department of Administration, Madison, WI. http://www.google.com/url?sa=t&source=web&ct=res&cd=1&url=http%3A%2F%2Fwww.ecw.org%2Fprod%2Fww_roadmap.pdf&ei=7OwcSYHeCYKUsQPKiKyPCA&usg=AFQjCNHeYf9Su2AE6-300yswCUuBsPrI8A&sig2=T-PaggszDsSqJp-6vp3png Wisconsin. 2003. Report on the Development of Energy Cosumption Guidelines for Water/Wastewater. State of Wisconsin Department of Administration, Madison, WI. http://www.google.com/url?sa=t&source=web&ct=res&cd=1&url=http%3A%2F%2Fwww.ecw.org%2Fprod%2Fww_roadmap.pdf&ei=7OwcSYHeCYKUsQPKiKyPCA&usg=AFQjCNHeYf9Su2AE6-300yswCUuBsPrI8A&sig2=T-PaggszDsSqJp-6vp3png Wright, C.P. (2008) Leak Detection Program Summary Report. Southwest Florida Water Management District http://www.swfwmd.state.fl.us/conservation/audits/files/leak_detection_report.pdf

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Appendix 1 – Design Best Practices Checklists for New Water and Wastewater Facilities Excerpted from Roadmap for the Wisconsin Municipal Water and Wastewater Industry (Wisconsin, 2002). There is considerable overlap with the best practices identified in this guide. New Water Treatment Facilities

Provide ample storage capacity and flow flexibility to accommodate variable demand.

Specify high efficiency motors and pumps. Include control systems and software. Consider low-energy backwashing system options. Optimize chemical requirements. Install baffled flocculation tanks instead of mechanical flocculators. Use staged, load-adjusted, small air compressors for air-fed ozone systems. Consider alternative solution mixers that are non-mechanical (static or hydraulic

jump). Consider minimal energy concept, with respect to spatial layout of a new water

extraction / treatment system to minimize pump distance and head requirements Select water treatment system technology that reflects the best life-cycle

economics, with respect to environmental compliance Use lower friction pipes (estimated 6-8 percent energy savings)

Apply not-quite-potable, treated wastewater to:

Recharge aquifers. Support industrial processes. Irrigate certain crops. Augment potable water, when and where appropriate.

New Wastewater Treatment Facilities

Use attached-growth type of secondary treatment (trickling filters or biological contactors) in lieu of activated sludge for medium-sized plants to reduce energy costs.

Provide ample storage capacity and flow flexibility to accommodate variable demand.

Specify high-efficiency motors and pumps. Include control systems and software. Employ initial removal of large debris in lieu of comminutors to avoid increased

secondary treatment costs. Consider low-energy backwashing system options. Optimize chemical requirements. Apply baffled flocculation tanks vs. mechanical flocculators. Use staged, load-adjusted, small air compressors for air-fed ozone systems. Consider alternative solution mixers that are non-mechanical (static or hydraulic

jump).

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Apply fine-bubble aeration instead of coarse bubble aeration. Consider UV for disinfection, instead of chemical or ozonation systems. Minimize infiltration of groundwater and rainwater into sewage collection system

to reduce pumping requirements (seal joints, lining, PVC pipe, bypasses, etc.).

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Appendix 2 – Funding Sources, Renewable Energy Specialists, and Other Resources Funding Sources WIFA – Water Infrastructure and Financing Authority (Arizona) http://www.azwifa.gov/ Clean Water State and Safe Drinking Acts (State Revolving Fund Program) http://www.epa.gov/safewater/ DOLA, CDPHE, CWRPDA National Water Program Strategy (Response to Climate Change) Direct and Leveraged Loans Disadvantaged Community Loans Colorado Water Resources and Power Development Authority http://www.cwrpda.com/Programs.htm

Small Hydro Loan Program (Colorado only) Water Resources and Power Development Authority Engineering up to $150K per year, $15,000 per local government Up to $2 million per borrower, 2% for 20 years SRF – Planning and Design Grants have been a success Energy Efficiency and Conservation Block Grant Program (EECBG) http://www.usmayors.org/climateprotection/documents/eecbghandout.pdf U.S. DOE 68 % to Municipalities (30,000+) 28% to States 2% to Tribes USDA Section 9006 Energy Programs http://epa.gov/region09/cleanup-clean-air/pdf/az-waste-energy/renewable-energy-efficiency-pgm-farm-bill-sec.pdf Section 9007 in new farm bill AG producers and rural small business 25% grant Water / Energy Partnerships

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Solar Investment Partnership Solar Development Companies

Sol Equity IEG – Independent Energy Group – ASU developerCamilla Strongin (602) 346-5054 Code Electrical Mark Holahan (602) 438-0095 Sun Edison – (solar systems 50 KW or bigger) Deer Path – (Boston)

Renewable Energy Specialists Barbara Lockwood – APS (602) 250-3361 Tom Hansen – TEP (928) 337-7322 Lori Singleton – SRP (602) 236-3323 Terry Hudgins – Green Ideas (480) 620-4795 (mobile) Ken Starcher – Alternative Energy Group – (806) 651-2296

Tom Acker – Department of Mechanical Engineering – Northern Arizona University (928.523.5200)

   Other Resources Agricultural Pumping Efficiency Program http://www.pumpefficiency.org National Environmental Services Center http://www.nesc.wvu.edu/index.cfm USEPA Small Water Systems http://www.epa.gov/OGWDW/smallsystems/index.html Consortium for Energy Efficiency http://www.cee1.org/ WATERGY – Water and Energy Efficiency http://www.watergy.org/ Focus on Energy – State of Wisconsin http://www.focusonenergy.com/

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Appendix 3 – Case Study Summaries The following case studies were completed at Northern Arizona University and the University of Arizona as part of this project. Each consists of an evaluation of existing water and energy use at a rural Arizona water or wastewater facility, together with recommendations for best practices, presented herein, that may be of value at the respective facilities.

• Benson, AZ: Energy, Water, and Wastewater • Grand Canyon National Park, AZ: Energy and Wastewater • Kartchner Caverns State Park, AZ: Energy, Water and Wastewater • Patagonia, AZ: Energy, Water and Wastewater • Patagonia Lake, AZ: Energy, Water and Wastewater • Payson, AZ: Energy and Wastewater

Slide Rock State Park, AZ• : Energy and Water

A Water / Energy Best Practices Guide for Rural Arizona’s Water & Wastewater Systems 41

AN INVESTIGATION OF ENERGY USE, POTABLE WATER AND WASTEWATER TREATMENT AT BENSON, ARIZONA

By Brian Billy and Muniram Budhu Background The City of Benson is located in southeastern Arizona, approximately 45 miles south of Tucson, AZ, along Interstate 10 (I-10). It is located within Cochise County and has a population of 4,934 (2006 census). The area is experiencing a growth rate of 4.7% based on figures from 2000 to 2005. The city is located within the Upper San Pedro Watershed at an elevation of 3,580 ft above sea level. The city utilizes groundwater as its sole water source. In early 2007, wells that produced water containing elevated levels of arsenic were taken off line, and the water system was modified so that all water was supplied by low-arsenic wells located in the upper southwest region of the city. Compliance with the EPA’s present arsenic rule is an issue of concern for Benson. The water uses in the area are: municipal, agricultural, livestock, industrial, and riparian. This study deals only with the municipal use. The electricity provider for the City of Benson is the Sulphur Springs Valley Electric Cooperative (referred to as Sulfur Springs).

WATER Supply & Pumping

SKP 

The City of Benson pumped approximately 842 acre-ft (af) of water in 2007. The average per capita water usage is 150 gallons/person, with 1794 connections. The four wells that currently supply the city are Jennella, Cochise College, 302, and 291. Static water depths have been measured at 463 ft, 450 ft, 580 ft, and 571 ft respectively; the water table has not

demonstrated a significant amount of drawdown with the current pumping regime. Figure 1 shows the relative location of the wells and tanks. The Cochise College and Jennella Wells work in tandem and currently provide 80% of the total water supply to the City of Benson. The 302 and 291 wells supply the Benson west tanks and the growing population along State Route 90.

Figure 2: Jannella Well  Figure 1: Wells and Tank locations in Benson, AZ

Treatment Raw water is not treated. In the event of bacterial exceedance, the system is spot chlorinated and flushed. The water quality is monitored daily and monthly compilations of lab results are submitted to the Arizona Department of Environmental Quality. Transmission, Storage & Distribution Groundwater is pumped to the surface and conveyed to multiple storage tanks within the city. Two booster pumps are needed to supply the SKP development area and convey water from the 302 well to the 302 tank. The total system production is approximately 274 million gallons annually and total storage capacity is 2.45 million gallons. The topography allows for the distribution system to convey the water via gravity through 4-in., 6-in., and 8-in. pipes. Distribution occurs over an area with elevation difference of 616 ft. Pressure reducing valves are utilized to maintain a pressure of 40-80 psi within the service regions. The ability to utilize gravity for conveyance from storage is one of the major efficiencies within the Benson system.

WASTEWATER TREATMENT The wastewater treatment plant (WWTP) is located in the northern part of town (see Fig. 1) along I-10,, north of the main business district,at elevation 3,515 feet. The service area includes the main business district and residential areas west of the San Pedro River. The original treatment plant (pond system) was moved to its current location in 1960 and was completely rebuilt in 2002 to its current operation. The flows are metered at both the influent and effluent pump stations. The effluent is used to irrigate the city golf course at no cost. Collection / Conveyance The city’s wastewater is conveyed to the plant via gravity and received at an average rate of approximately 420,000 gallons per day (gpd). During the peak season the flow rate increases to nearly 520,000 gpd. The system works efficiently and there have been no significant maintenance issues. The installed collection piping is a combination of concrete, vitreous clay, and PVC types. Treatment The WWTP is automated and can be monitored remotely from a computer terminal utilizing SCADA software. The SCADA system monitors water levels within the influent station wet well and turns on the influent pumping system as needed. Multiple pumps are on standby for times when influent flows exceed single pump capacity. The total maximum pumping horsepower available for influent is 60 hp. The motors utilize 3-phase power and are complete with surge protection and soft start capability. The total length of wastewater travel in the WWTP has been estimated at 0.25 miles. Once influent is received from the wet well, the remaining WWTP process is gravity-driven. The processing starts with influent passing into an agitated grit chamber where it is injected with air. Blowers are utilized for this process and represent one of the major energy consumers, since they run 24 hrs a day. The sludge passes through a mechanical screen and through a series of gated chambers for introduction into the bioreactor

where it is treated by an activated sludge process , with aeration. Average residence time of the sludge is approximately 48 hours. Air is constantly injected to promote digestion. The processed wastewater passes through clarifiers and sand filters, treated with chlorine and UV light, and then passed to the effluent storage area. The lab analysis for the process is performed daily and monthly reports are developed for review by the Arizona Department of Environmental Quality.

Time and duration of pumping operations is dependent upon the levels in the influent pump station and the effluent storage areas. These areas have thresholds programmed into the system to automatically increase/decrease the amount of processing. The elevation change is approximately 14-16 feet from the bar screen to the effluent storage ponds. The effluent pump station, which is fully automated, delivers the effluent to the storage ponds. In the event that overflow or bypass is needed, the plant can revert back to its original operations and store the waste in its backup aeration ponds, which are normally dry. This process is only needed during the monsoon season. There is no discharge of effluent; the vast-majority is used to irrigate the city-owned golf course, which pays no fee for the reclaimed water.

The effluent is also used to wash down equipment in the WWTP, and once used is re-circulated for treatment within the facility. Sludge processing continues to the drying beds, where there is sufficient area to obtain good drying times in the Arizona sun. The slude is then transported to the local solid waste facility for disposal.

SYSTEM METRICS Monthly water pumping data were provided by the City of Benson. The wastewater processing energy expenditures were provided by Sulphur Springs. The wastewater processing figures were provided on a monthly time step by plant personnel and are estimates derived from 2008 billing records. The records for gas usage were not considered since they were not readily available and are only used for back up generators that are periodically tested. Since the water distribution operations were modified in 2007 to accommodate new arsenic standards, the tables to the right reflect the operations of a system within its transition period.

Benson Potable Water System (2007) Benson Wastewater Treatment Plant

Number of Gallons Pumped 274,563,200 Gallons of Wastewater

Processed 135,360,000

Service Population 5,000 Service Population 5,000

Gallons Pumped per Day 752,228 Average Gallons Processed per Day 370,850

Gallons Used per Person per Day 150 Gallons Processed per Person

per Day 74

Annual kWh Usage 856,659 Annual kWh Usage 984,516

kWh/kgal 3.12 kWh/kgal 7.27

Table 1: Water Distribution and Wastewater Treatment Plant Metrics

RECOMMENDATIONS/SUGGESTIONS Presented below are best practice recommendations and suggestions developed as part of our qualitative evaluation.

NO OR MINIMAL COST • Balance revenue and expenses. • Understand how energy and water are utilized in the system. • Review system plans, specifications, and records before considering upgrades/improvements. • Evaluate costs for different available water sources. • Secure operations and maintenance guides and training for city staff when new systems/components are installed. • Further investigate blending of high- and low-arsenic ground water supplies.

LOW TO MODERATE COST • Evaluate pumps, blowers, and motors for upgrade to either high-efficiency or VFD, as appropriate. • Investigate available technologies for arsenic and other heavy metal reduction for future consideration. • Consider high-efficiency ballasts and bulbs in the UV disinfection process, and elsewhere within the facility. • Adequately ventilate or sunshield all electrical and mechanical equipment in warm weather. • Utilize off-peak power usage strategies. • Develop water audits and implement leak detection programs. • Implement water budgets and rate structures. • Create financial (or other) incentives for water customers to conserve. • Adopt water-efficient codes and ordinances. • Create water conservation education programs.

MODERATE TO HIGH COST • Identify and eliminate areas where there are inefficiencies in potable water booster pumping and pressure management. • Replace old meters and install automated units. • Optimize treatment processes to reduce water and energy consumption. • Reduce friction/energy losses in pumps, fans, pipes, valves, and production wells. • Utilize renewable energy, as appropriate.

CONTACT INFORMATION • Benson water system, contact Brad Hamilton, City Engineer: (520) 586-2245. • Benson WWTP, contact Larry Napier: (520) 586-2245. • Sulphur Springs Valley Electric Cooperative, contact Dave Bane,: (520) 515-3472. • Project Sponsor: Arizona Water Institute. • Partnering Universities: Northern Arizona University, University of Arizona. • Lead case study author, Brian Billy: [email protected].

AN INVESTIGATION OF ENERGY USE, POTABLE WATER AND WASTEWATER TREATMENT AT GRAND CANYON NATIONAL PARK, ARIZONA

By Matthew Roberts, Charlie Schlinger and Steve Mead Background The Grand Canyon is one of the natural wonders of the world. Well-concealed behind the spectacular geology and unique flora and fauna that give this National Park distinction is the engineering wonder of providing water and wastewater services to tens of thousands of daily visitors. Across the world, providing drinking water accounts for over 2% of all energy consumed, but in this national gem, water is much more difficult to come by, accounting for nearly 25% of the energy used within the Park. This case study of the Park’s water and wastewater systems helps determine the unique challenges their operators face and provides guidance for solutions. The Grand Canyon National Park receives over 4 million visitors each year who can observe, experience, and take home sustainable living practices; the Park’s water and wastewater systems should be at the backbone of this paradigm.

WATER Supply, Treatment and Transmission In terms of energy consumption, delivery from the source to the user is much more important than the treatment of drinking water. The supply of drinking water for most of the Park is Roaring Springs, about 4000 ft below the North Rim. Sediment is removed and chlorine gas is used for disinfection at Roaring Springs. The water then travels by gravity flow through the Trans-Canyon Pipeline (TCP) to Indian Gardens with connections at Cottonwood Campground and Phantom Ranch. The TCP crosses a suspension bridge over the Colorado River and passes through a directionally drilled borehole to Plateau Point where there is enough residual pressure to deliver water to Indian Gardens. Due to the TCP’s age, delicate condition and frequent failures, the flow is maintained constant and is not turned down, even

during periods of low demand. Consequently, excess water that is not needed at the South Rim is de-chlorinated and discharged to Garden Creek. Two pipes lead from Indian Gardens delivering drinking water to the South Rim: one branch follows a directionally drilled borehole to storage tanks on the South Rim; the other branch follows the Bright Angel Trail and has connections at 3-Mile Rest House and 1 ½-Mile Rest House.

Figure 1: Potable Water Distribution and Treatment at Grand Canyon National Park

WASTEWATER TREATMENT

Anthracite Filter

Bar Screens

Soda Ash Addition for pH Control

Influent: 500,000

gal per dayGrit

Chamber

Addition of Alum for

Coagulation & Flocculation

Secondary Clarifiers

Tertiary Clarifiers

Grit Hauled to Landfill Digester

Aerator

Aerator

Sludge Hauled to Drying Beds

Drying Beds Convert Biosolids from Class

B to Class A for Landfill Capping

Disinfection with Chlorine

Gas

Effluent Discharge to Coconino Wash and Reuse within

National Park

Activated Sludge Return

A daily average of 500,000 gallons of wastewater from South Rim facilities, hotels, housing, offices, businesses, etc., is gravity-fed to the nearby South Rim wastewater treatment plant (WWTP). A primary clarifier and bar screens remove large debris, which is collected and hauled to a landfill. Soda ash is added to the wastewater stream to adjust the pH to 7.2-7.5 before it flows into the digester and aeration basins. The aeration basins use coarse-bubble diffusers with three 15-hp and two 50-hp blowers supplying the air. The digestion basin uses a 25-hp agitator while the aeration basins use two 50-hp agitators. Excess solids are removed in a secondary clarifier where some are returned to the digestion basin, and the remaining bio-solids are hauled to drying beds. These drying beds receive biosolids, including mule dung, from within the park, and provide conversion from class B to class A biosolids, suitable for landfill capping. After secondary clarification, the wastewater stream has an addition of alum to facilitate a coagulation/flocculation step followed by a third clarifier. Chlorine gas is used to disinfect the wastewater before discharging Class A reclaimed water to Coconino Wash, or for irrigation reuse within the Park.

Figure 2: Wastewater Treatment at Grand Canyon National Park

SYSTEM METRICS These metrics are based on the year 2007 to obtain a snapshot of the Park’s operations. The estimates for potable water pumping were based on annual figures provided from the Park. Wastewater flows were estimated by the wastewater treatment plant’s operator. Electrical usage for water and wastewater systems were developed from Arizona Public Service billing records. Natural gas consumption figures were not considered because natural gas is not directly used in the treatment of potable or wastewater.

Average Potable Water Demand

Average Wastewater Influent Flow

Electricity Use Potable Water

Electricity Use Wastewater

Annual Power Use Potable

Annual Power Use Wastewater

126.9 Mgal/year 347.6 kgal/day

241 gpm

182.5 Mgal/year 500 kgal/day 347.2 gpm

23-27 kWh/kgal 8.5 kWh/kgal 3,445,120 kWh/year $113,700/year

1,547,040 kWh/year $51,100/year

Mgal=million gallons, kgal=thousand gallons, gpm=gallons per minute

Table 1: Water and Wastewater Metrics at Grand Canyon National Park

RECOMMENDATIONS/SUGGESTIONS Presented below are some best practice recommendations and suggestions that we identified as part of our qualitative evaluation.

NO OR MINIMAL COST • Assess the need of the tertiary treatment of wastewater: it is rarely done in comparable systems. • Discuss alternatives regarding the chlorination of drinking water: using helicopters to transport chlorine gas is energy consumptive. • Coordinate raw water production/distribution with treatment process capacity. • Assess costs of maintaining existing facilities versus upgrading over the expected life of the system. • Review system plans, specifications, and records with plant operators, maintenance staff, and engineers before considering upgrades/improvements. • Evaluate costs for different available water sources. • Secure operations and maintenance guides and training for park staff when new systems/components are installed. • Allow the bar screen rake to rise only enough to expose more clean bar screen, letting excess water drip off before deposition in a dumpster, thereby

not hauling excess water weight to the landfill. LOW TO MODERATE COST

• Implement a water conservation and education program. • Evaluate pumps, blowers, and motors for upgrade to high-efficiency or VFD. • Directly utilize heat in blower/pump room to keep biological activities warmer and thus more reactive or to heat nearby buildings in the winter. • Develop a cost analysis and implement capital improvement planning. • Reduce leakage through pressure management. • Adopt water-efficient ordinances and codes. • Conduct an energy audit of all pumps and blowers and their total energy consumption. • Retrofit facilities with energy efficient lighting, using high-efficiency ballasts and bulbs. • Perform a loss/leakage survey for both reclaimed water and influent wastewater. • Create financial or other incentives for water users to conserve instead of increasing production/treatment capacity. • Utilize off-peak power usage strategies. • Adequately ventilate or sunshield all electrical and mechanical equipment in warm weather. • Take measurements and evaluate the data prior to making future improvement plans.

MODERATE TO HIGH COST • Reduce friction/energy losses in pumps, fans, pipes, valves, and production wells. • Replace the entire TCP with a larger-diameter lower-friction-loss steel pipe that can handle washouts, increased future demands, and water pressure

transients during valve closures or flow adjustments. • Reduce pressures within the new TCP with an electric turbine to generate supplemental electricity power. • Use a MIOX system at Roaring Springs: the system runs on salt, thus mules can safely bring in the raw materials. • Install a hydro-electric turbine on Bright Angel Creek, near Phantom Ranch, to generate power for Phantom Ranch and to run a UV-dechlorination

unit, discharging surplus water to Bright Angel Creek, which Roaring Springs normally feeds. • Change coarse-bubble diffusers to fine-bubble diffusers to increase aeration efficiency. • Utilize renewable energy wherever appropriate throughout the water and wastewater systems.

CONTACT INFORMATION Please contact the authors of the study with questions about the study, supporting data, and background information: Matt Roberts ([email protected]), Charlie Schlinger ([email protected]) or Steve Mead ([email protected]) at Northern Arizona University. For more information on Grand Canyon National Park, please contact Steve Rice, Hydrologist by email: [email protected]. Project Sponsors: Grand Canyon National Park, Arizona Water Institute, NAU Ecological Monitoring & Assessment.

AN INVESTIGATION OF ENERGY USE, WATER, AND WASTEWATER TREATMENT AT KARTCHNER CAVERNS STATE PARK, ARIZONA

By Brian Billy and Muniram Budhu Background Kartchner Caverns State Park is located in southeastern Arizona, approximately 9 miles south of the town of Benson along State Route 90. The 550-acre park attracts over 200,000 visitors annually. The demands on the water and wastewater systems are based upon the influx of visitors to the caves, and on campground utilization. The peak visitation and water demands occur between the months of November and April. The largest constructed facility is the 23,000-square-foot Discovery Center that sits at the base of the cave inlet. It serves as the main collection area for visitors. The park has bathroom facilities located at each of: the Discovery Center, the trailhead area, and at the main campground area. The park is equipped to handle day-use visitors, campers, and recreational vehicles (RV’s). Other notable facilities are the wastewater treatment plant (WWTP), maintenance area, ranger residences, and various offices. Overall groundwater levels within the parks have been steadily declining over the past 10 years and studies are in progress to evaluate when the wells that serve the park will reach non-sustainable levels.

WATER Supply & Pumping

Figure 1: Kartchner Caverns SP Water Distribution System

The sole source of water for the park is groundwater. There are multiple wells located within the park; only well #2 currently serves the park. The well is located at the southwest side of the park below the main campground area. The average annual pumping for 2007 was 2.3 million gallons (MG). The average daily withdrawal is 6,000 gallons per day (gpd) but can be as high as 20,000 gpd during the peak season and as low as 4,000 gpd. The water is pumped to the surface utilizing a 3-hp 480 V 3-phase submersible pump. The system is manually operated and requires that the pump be turned on every morning in order to fill the 3000 gallon storage tank (elev. 4732) located northwest of the well. The elevation difference between the well and the tank is 75 ft over a horizontal distance of 1800 ft (4% grade). Once the tank is full, the pump is turned off and the park utilizes the elevation head to drive the flow. If demand is high, the tank will be filled first and the upper valve will be closed and the park will then be serviced directly from the well. Metering for the potable water system is done only at the well site.

Treatment The pumped water is treated well head, when the submersible pump is operating, prior to being conveyed to other parts of the system. A small dosing pump injects a chlorine solution from a holding tank that contains a solution of 20 gals of water plus 2 quarts of 12% sodium hypochlorite. Storage & Distribution Groundwater is fed through the system via an 8-in. PVC main, with 2-in. and 3-in. PVC laterals. The system pressurization varies from 15-90 psi throughout the park. The area most prone to low pressures is the main campground area. The system has two booster pumps located near the ranger residences and below the water storage tanks. Backflow prevention devices and pressure reducing valves are located throughout the system to maintain pressure, meet demand, and protect the water supply.

Figure 2: Layout of Kartchner Caverns State Park

WASTEWATER TREATMENT The wastewater treatment plant (WWTP) at Kartchner is located at the southeastern portion of the park at an elevation of 4574 ft. The topography is such that all wastewater flows under the action of gravity to the WWTP. The wastewater comes from bathrooms, ranger residences, the campground uses (including showers), and the Discovery Center. The park is also equipped with a dump station that consists of two 110 ft lanes (to accommodate RVs), two sumps, a wastewater tank, and a non-potable water source. The WWTP has a maximum operating capacity of 20,000 gpd, and processes approximately 2.1 MG annually at an estimated average daily rate of 6,000 gpd. Wastewater flows as high as 22,000 gpd have been recorded; however, the flow meter may be faulty and this peak flow remains in question.. Collection and Treatment The collection system operates solely under the action of gravity and delivers wastewater to a lift station. The station’s holding tank is equipped with baskets for segregation and removal of large waste, along with grit removal. The tank has two submersible 4 hp grinder pumps that alternately lift the water to the WWTP. The tank wastewater elevation is monitored by a mercury-type flow switch that controls pumps’ operation. The control levels are set to stop all pumps at a low liquid level and start the first pump at a high level. The lift station moves the wastewater to the intitial point where treatment begins. The WWTP plant is a Schreiber package plant consisting of two Bio-Reel treatment units. The Bio-Reel systems are housed in a reinforced concrete tank and operate in parallel. There is an anaerobic stage and an aerobic aeration chamber linked to a blower that infuses air into

the system. The unit includes a large number of tubular spirals that are confined in a reel-like rotary cage, which provides for the growth of attached microorganisms (bugs). The reel assembly is immersed in the reactor vessel and rotated by air. During rotation, air bubbles are trapped in the tubes, providing oxygen to the biomass, and circulating the wastewater through the tubes. Within the anaerobic chamber the wastewater is introduced to the bugs. The nutrients are transferred to the biomass (adhering to the tube walls) for BOD reduction and ammonia (NH3-N) nitrification. The ammoniated compounds flip the ammonia into the nitrate stage and when it hits the aeration zone it converts from nitrite (NO2) to nitrogen gas and oxygen, the latter being consumed by denitrifying bugs. The processed wastewater is then fed into an effluent tank where it is collected and pumped to an orchard, adjacent to the plant, where it is used for irrigation. During periods of high-flow the effluent tank can be bypassed and effluent is discharged to two storage ponds. The park changed its permit with the Arizona Department of Environmental Quality and does not have to monitor wastewater contaminants. The processed sludge collects at the bottom of the Bio-Reel reactor vessel and is transported to a solid waste disposal facility about every 2 years. The plant has several diesel single-phase backup power units, in the event of power outages.

SYSTEM METRICS The high kWh/kgal figures for the WWTP can possibly be attributed to a faulty wastewater flow meter and the inability to quantify the amount of kWh attributable to the plant itself. According to park staff, the park is in the process of performing a systems audit and inventory to better understand the functioning of their system. The HVAC system’s chiller and boiler have been documented as being two of the biggest users of power. Diesel/gas usages were not considered because the data was not made available. However, a future investigation into diesel/gas use is planned.

Kartchner SP Water System (2007) Kartchner SP WWTP (2007) Number of Gallons Pumped 2,340,268 Gallons of Wastewater Processed 2,106,241

Annual Park Visitors 225,000 Annual Park Visitors 225,000 Gallons Pumped per Day 6,412 Average Gallons Processed per Day 5,771

Gallons Pumped per Person per Day 10.4 Gallons Processed per Person per

Day 9.4

Annual kWh Usage 6,633 Annual kWh Usage 49,748

kWh/kgal 2.83 kWh/kgal 23.62

Table 1: Water Distribution and Wastewater Treatment Plant Metrics

RECOMMENDATIONS/SUGGESTIONS Presented below are best practice recommendations and suggestions identified as a result of our qualitative evaluation.

NO OR MINIMAL COST • Check manholes in the park to ensure they are not exposed to the open environment and remain free of large debris. • Ensure the system is not receiving and processing excessive storm water due to intrusion into the collection system. • Obtain an accurate count of all systems that are drawing the most energy and determine accurate estimates of kWh usage. • Assess the balance between revenue and expenses. • Understand how water and energy are utilized throughout the system. • Review system plans, specifications, and records before considering upgrades/improvements. • Evaluate costs for different available water sources. • Secure operations and maintenance guides and training for park staff when new systems/components are installed.

LOW TO MODERATE COST • Evaluate pumps, blowers, and motors for possible upgrade to either high-efficiency or VFD. • Retrofit facilities with energy efficient lighting, using high-efficiency ballasts and bulbs. • Pressurize the system only when necessary (periods of high demand). • Develop a cost analysis and implement capital improvement planning. • Develop water audits and implement leak detection programs. • Coordinate water production/delivery with treatment process capacity. • Install/repair automated switch for the water distribution tank. • Install additional flow meters around the park to obtain an idea of where most of the water is being used and cut back on losses. • Adequately ventilate or sunshield all electrical and mechanical equipment in warm weather. • Consider and, as appropriate, adopt off-peak power usage strategies.

MODERATE TO HIGH COST • Utilize cold water from the well to offset chiller operation. • Reduce friction/energy losses in pumps, fans, pipes, valves, and production wells. • Optimize treatment processes to reduce water and energy consumption. • The potential for solar electric generation is currently being investigated. Sulphur Springs has agreed to pay half of the cost, or $4/watt • Install a solar water heater on the roof of the Discovery Center to offset gas usage. • Install metering devices for the WWTP to evaluate the performance of the pumps and bio-reels.

CONTACT INFORMATION • For more information on the Kartchner WWTP Facility, please contact Rob Van Zandt by phone at (520) 988-0155. • Project Sponsor: Arizona Water Institute. • Partnering Universities: Northern Arizona University, University of Arizona. • Lead case study author, Brian Billy: [email protected].

AN INVESTIGATION OF ENERGY USE, WATER SUPPLY AND WASTEWATER TREATMENT AT PATAGONIA, ARIZONA

By Brian Billy and Muniram Budhu Background The City of Patagonia, AZ is situated in Santa Cruz County and located approximately 60 miles SE of Tucson, AZ at an elevation of 4,055 ft. The community has a population of 825 (2006 census). The town is located within the Sonoita Creek Watershed and is outside Active Management Areas, which are designated by the Arizona Department of Water Resources. In 2003 a multi-agency grant was approved for upgrading the existing wastewater treatment plant (WWTP) and to rehabilitate portions of the sewer collection system. The plant upgrade has improved the quality of effluent discharged to Sonoita Creek by decreasing overall nitrogen levels. The sewage line rehabilitation has decreased the amount of wastewater leaking into the regional aquifer, resulting in improved health and environmental conditions. The electricity provider for the city is the Sulphur Springs Valley Cooperative (referred to herein as Sulfur Springs).

WATER Supply, Pumping & Storage

Figure 1: Water System

The City of Patagonia relies solely upon groundwater to serve its residents. Two wells, operated alternately and equipped with submersible pumps, are located within the center of town and supply water directly into the distribution system and to an upper storage reservoir. The static water levels in the wells vary from 15 to 30 feet below the land surface, depending on demand and time of year. The two recently-overhauled 30-hp submersible pumps are controlled by telemetered signals from reservoir water-level sensors. The pumps operate daily, for up to six hours, at a rate of 325 gallons per minute (gpm), which yield nearly 110,000 gallons per day (gpd). The upper storage reservoir consists of two 200,000 gallon underground tanks. When the pumps are on, in addition to pressurizing and supply water to the distribution system, they pump water to the reservoir. There is metering at the well head. The water is pumped upgrade at slope of 6.5% for 0.75 miles (see Fig. 1 right). Treatment Currently there is no well-head chlorination due to malfunctioning chlorinators. As a result, the water supplied to the system when the pumps are running is untreated. The city is in the process of identifying replacements or repairs for the well-head chlorination system. Presently, staff manually add chlorine tablets to the storage tanks every few days. Residual chlorine levels are monitored to maintain compliance with Safe Drinking Water Act standards. Distribution Treated water is conveyed either from the storage tanks via gravity, or by direct well pumping, to the service area, which has 414 connections. The pressure in the uppermost portion of town is 65 psi and rises to 95 psi in the lower portion. Pressure reducing valves are used to regulate the pressure. Water from storage is conveyed to the service area utilizing the same pipe (8-inch main) that is used to transport it to the reservoir. The main distribution pipeline bisects the city’s business district, with laterals extending to various parts of the service area. The pipes range in size from 2 in. to 8 in. and are made primarily of ductile iron, Transite, and PVC. Leak detection is done by regular meter monitoring of flow at the well head and at points of individual use. Currently, there is no booster pumping to outlying or high-elevation areas. One key issue that has been identified is malfunctioning check valves at the wells. The existing valves occasionally stick in the open position when the pumps turn off. This allows water to pass back through the check valves and back into the wells. Not only does water get lost from the distribution system back to storage, but there is potentially a condition of suction in the distribution system.

WASTEWATER TREATMENT The treatment plant is located in the southwest part of the city at an elevation of 4027 ft on z 9.5-acre site adjacent to Sonoita Creek, within the 100-yr flood plain. The sewer system of Patagonia was constructed in 1965 under the town's "Sewer Improvement District One" project. The sewage collection system consists of 19,000 linear feet (lf) of 6, 8, and 10-inch gravity sanitary sewer pipes. Subsequent improvements to the system include rehabilitation of approximately 5,500 feet of the sewer lines and installation of an oxidation ditch for extended aeration wastewater treatment. Conveyance and Treatment The wastewater flows a horizontal distance of 3 miles at downward grade of 0.32% from the service area in a gravity-driven collection system. The overall system has a total design capacity of 110,000 gallons per day (gpd); however, on average the plant generates 60,000 gpd of effluent with 99-100% BOD removal. The influent is screened to remove large items and then passed through a grit chamber to remove the large colloidal particles. The wastewater is then lifted a vertical distance of approximately 10 ft and a horizontal distance of nearly 50 ft utilizing two 4-in. 10-hp grinder pumps that operate alternately . On average, the pumps operate 20 times daily for 15 minutes at 200 gpm. The plant utilizes activated sludge with an anoxic denitrifying chamber to ensure

Figure 2: Sludge Cake Belt Press at Patagonia WWTP

maximum nitrogen removal. The first process consists of a pre-anoxic basin where influent wastewater, return sludge from the clarifier, and nitrate-rich mixed liquor pumped from the effluent end of the aeration tanks are mixed together to form the liquor used in the digestion process. The process proceeds through a series of aeration tanks where the air is fed by 25 hp blowers to maintain a set level of dissolved oxygen and promote aerobic digestion. After passing through two separate aeration chambers the water is fed into a clarifier where the heaviest solids and microorganisms are allowed to settle out. The clarified water then exits through V-notch weirs and enters 3 separate chlorination contact zones where it is chlorinated, de-chlorinated, and then discharged into Sonoita Creek. The plant is fully automated and is equipped with a diesel back-up generator in case of power outages. The main energy consumption at the plant can be attributed to the blowers that run 24 hrs daily with one added blower needed during the summertime. The remaining processed sludge is passed through a belt press (see Fig. 2 above) and made into cake for transport to the city landfill.

SYSTEM METRICS Figures were developed from utility billing records received from Sulphur Springs and the City of Patagonia. The amount of pumping was based on monthly figures for both wells and then compared to the monthly billing records. These metrics were based on the year 2007 to obtain a snapshot of the city’s operations. Natural gas consumption figures were not considered because these data were not made available. The gas energy usage is currently being investigated.

City of Patagonia Potable Water System (2007) City of Patagonia Wastewater Treatment

Plant Number of Gallons Pumped 41,885,700 Gallons of Wastewater Processed 21,900,000

Service Population 822 Service Population 822 Gallons Pumped per Day 117,656 Average Gallons Processed per Day 61,517

Gallons Pumped per Person per Day 143 Gallons Processed per Person per Day 75

Annual kWh Usage 56,376 Annual kWh Usage 295,500 kWh/kgal 1.35 kWh/kgal 13.49

Table 1: Water & Wastewater Metrics

RECOMMENDATIONS/SUGGESTIONS Presented below are best practice recommendations and suggestions identified as part of our qualitative evaluation.

NO OR MINIMAL COST • Evaluate the balance betweem revenue and expenses. • Understand how water and energy are utilized throughout the system. • Review system plans, specifications, and records before considering upgrades/improvements. • Secure operations and maintenance guides and training for park staff when new systems/components are installed.

LOW TO MODERATE COST • Evaluate all pumps, blowers, and motors for upgrade to either high-efficiency or VFD, as appropriate. • Fully assess blowers operation and quantify how much energy they consume on average and during peak seasons. • Repair/replace the malfunctioning check valves. • Adequately ventilate or sunshield all electrical and mechanical equipment in warm weather. • Utilize off-peak power usage strategies. • Develop water audits and implement leak detection programs. • Implement water budgets and rate structures. • Create financial (or other) incentives for water customers to conserve. • Adopt water-efficient codes and ordinances. • Create water conservation education programs. • Coordinate water production/delivery with treatment process capacity. • Retrofit facilities with energy efficient lighting. • Install chlorinators at the well locations.

MODERATE TO HIGH COST • • Reduce friction/energy losses in pumps, fans, pipes, valves, and production wells. • • Inventory and replace all non-functioning metering devices. • Optimize treatment processes to reduce water and energy consumption.

CONTACT INFORMATION • For more information on the City of Patagonia’s WWTP, contact Rob Van Zandt: (520) 988-0155, or Randy Heiss, City Manager: (520) 394-2220 • Project Sponsor: Arizona Water Institute • Partnering Universities: Northern Arizona University, University of Arizona • Lead case study author, Brian Billy: [email protected].

AN INVESTIGATION OF ENERGY USE, WATER SUPPLY AND WASTEWATER TREATMENT AT PATAGONIA LAKE STATE PARK, ARIZONA

By Brian Billy and Muniram Budhu Background Patagonia Lake State Park is located in southeastern Arizona approximately 7 miles west of the town of Patagonia, AZ. The park has an on-site water system and wastewater treatment facility. The unique nature of Arizona State Parks and their operations makes them a viable candidate for this study based on limited financial resources and the size of their operations. The seasonal weather variability directly affects the influx of visitors and therefore the overall ability to supply potable drinking water and process wastewater. Arizona’s environmental regulations that govern water supply and processing are different for state parks than for municipalities. The annual number of visitors to the park has been estimated at approximately 330,000; there are between 10-25 staff members and volunteers that operate the facilities. The park is equipped with 5 restroom facilities, visitor center, gift shop, camping and RV sites, and fish cleaning station. The park has 37 developed RV campground sites with electrical and water hookups, but not with sewage hookups. The park is open all year except for Christmas Day.

WATER Supply, Pumping and Treatment The park relies solely upon groundwater, which is provided by a centrally-located well that is equipped with a submersible 5-hp pump (3 phase 220 V). The wellhead is equipped with a backflow prevention device and meter. Annual pumping was measured at 3.7 million gallons in 2007. The daily average pumping is 6000 gallons per day (gpd) with pumping at up to 12,000 gpd during the peak season. The pump cycles on once per day on an average day, with more frequent cycling during times of peak demand. The water is chlorinated at the well site before transmission to storage. The chlorination system is activated by a sensor that detects submersible pump operation. The existing chlorination system presents operational and maintenance challenges to park staff and alternatives are being considered. Monthly water quality testing ensures that the water meets overall Safe Drinking Water Act standards, and chlorine residual levels are measured daily. Transmission, Treatment, Storage & Distribution Groundwater is conveyed uphill at a grade of 14% to two 15,000 gallon storage tanks. The vertical elevation change from the wellhead to the tanks is approximately 220 ft. Submersible pump operation is triggered when storage tank water level storage fall below a designated threshold. Stored water is supplied to the park area by gravity-driven flow. Due to the local topography, system pressures range between 40 psi at the well head to nearly 100 psi at the most-distant and lowest water spigot. Water supplied to distribution is not metered.

WASTEWATER TREATMENT The wastewater system includes: collection, with some treatment, pumping and evaporative lagoons (See Figure 1, left).

Figure 1: Wastewater System Schematic for Patagonia Lake State Park

The central collection area is located in the northern area of the park and collects waste from the ranger residences, the campground area, RV Park, and three of the five restrooms. The wastewater is transported via gravity flow to a lower collection area that is served by elements of an old contact stabilization waste water treatment plant. In particular the wastewater flows into an aeration holding tank before transport to the main lift station. The aeration process has been so effective that all sludge is being consumed prior to pumping to the main lift station. Wastewater is then pumped to the main lift station by two 10-hp pumps, which operate alternately. Located to the southwest, the Marina area has bathroom facilities equipped with showers and toilets. A fish cleaning station is close by. There is a nearby restroom facility called the Pointe, which is similarly equipped. Wastewater from each of these two areas is pumped directly to the main lift station, by means of a package mini-lift station with a 1-1/2 inch 2 hp grinder pump. Only one of min-lift stations is allowed to operate at a time, to avoid introducing too much wastewater into

the main lift station. The mini-lift stations do not cycle on unless there is sufficienc wastewater generation. Once the wastewater is received at the main lift station, which is approximately 150 ft above the Marina/Pointe and central collection area, it is further pumped to two evaporative lagoons. The vertical elevation change from the main lift station to the lagoons is approximately 75 feet. The main lift station is equipped with dual 10 hp alternating lift pumps. Due to the effectiveness of the simple aeration process, discussed above, minimal sludge has been introduced into the lagoons since 1994. The entire system is controlled by sensors that monitor the wastewater levels at the main lift station and the lower collection area. The park management Figure 2: Evaporative Lagoon at Patagonia Lake State Park

has the option of discharging from the lagoons to Patagonia Lake; however, that has occurred only once in the past 20 years. The discharge is chlorinated before being introduced to the lagoons. There is no daily monitoring because Arizona State Parks fall under a different monitoring classification than municipalities. However, monthly samples are taken and tested at an off-site University of Arizona lab. The wastewater flows are not directly measured because the park does not have flow meters that measure the amount of inflow into the evaporative lagoons. For the purposes of our evaluation, the wastewater flows were estimates at 2/3 of the total groundwater pumping.

SYSTEM METRICS Figures were developed from utility billing records received. These metrics are based on the year 2007 to obtain a snapshot of the Park’s operations. The estimates for potable water pumping were based on annual figures provided from the Park. Natural gas consumption figures were not considered because these data were not made available. Estimates of these gas energy amounts are currently being investigated.

Patagonia Lake State Park Water System (2007)

Patagonia Lake State Park Wastewater Treatment Plant

Number of Gallons Pumped 3,730,739 Gallons of Wastewater Processed 2,487,159 Annual Park Visitors 230,000 Annual Park Visitors 230,000

Gallons Pumped per Day 10,211 Average Gallons Processed per Day 6,814 Gallons Pumped per Person per Day 16.2 Gallons Processed per Person per Day 10.8

Annual kWh Usage 8,125 Annual kWh Usage 29,074 kWh/kgal 2.2 kWh/kgal 11.7

Table 1: Water Distribution and Wastewater Treatment Plant Metrics

RECOMMENDATIONS/SUGGESTIONS Patagonia Lake State Park has demonstrated several best practices in the design and operation of their wastewater treatment including the simplicity of the WWTP operation. Presently, park management and staff are considerating a small generator at the Patagonia Lake dam outlet to offset high energy costs. Presented below are some best practice recommendations and suggestions from our qualitative evaluation.

NO OR MINIMAL COST • Balance revenue and expenses. • Understand how water and energy are utilized throughout the system. Energy density for wastewater treatment, at nearly 12 kWh/kgal, appears

high, although this may well reflect the heavy dependence on lift stations. Still, improvements in this regard may be possible. • Review system plans, specifications, and records before considering upgrades/improvements. • Secure operations and maintenance guides and training for park staff when new systems/components are installed.

LOW TO MODERATE COST • Evaluate pumps, blowers, and motors for upgrade to either high-efficiency or VFD, if appropriate. • Conduct an energy audit of all pumps and blowers. • Retrofit facilities with energy efficient lighting, using high-efficiency ballasts and bulbs, as appropriate. • Develop a cost analysis and implement capital improvement planning. • Repair/replace the problematic chlorination unit with a unit that is easier to operate and maintain. • Reduce leakage through pressure management. • Utilize off-peak power usage strategies. • Adequately ventilate or sunshield all electrical and mechanical equipment in warm weather. • Take measurements and evaluate the data prior to making future improvement plans.

MODERATE TO HIGH COST • Install a flow meter at the lagoon site to monitor the influent. • Install flow metering devices within the park area to develop water audits and implement leak detection programs. • Install an extra storage tank to supplement the needs of the park during the peak seasons. • Reduce friction/energy losses in pumps, fans, pipes, valves, and production wells. • Utilize renewable energy wherever possible.

CONTACT INFORMATION • For more information on Patagonia Lake State Park, contact Rob Van Zandt: (520) 988-0155, or Dave Pawlik, Park Supervisor: (520) 287-6965 • Project Sponsor: Arizona Water Institute • Partnering Universities: Northern Arizona University, University of Arizona • Lead case study author, Brian Billy: [email protected].

AN INVESTIGATION ENERGY USE AND WASTEWATER TREATMENT AT PAYSON, ARIZONA

By Matthew Roberts, Charlie Schlinger and Steve Mead Background All too often, little thought is put toward estimating how much energy is consumed after water goes down the drain, but wastewater treatment systems may use considerably more energy than potable water systems. With increasing concern about global climate change due to the use of fossil fuels and their rising costs, the Arizona Water Institute (AWI) sponsored this case study to identify potential applications for increasing the efficiency and decreasing the overall energy use of water and wastewater systems in rural Arizona. The purpose of the case study analyses of rural water systems is to determine the unique challenges that these smaller systems face and provide some guidance in overcoming this complexity. The Northern Gila County Sanitary District operates The American Gulch Water Reclamation Facility in Payson, Arizona, serving over 15,000 people. This facility was designed for 2 million gallons per day (MGD) and can expect an average flow of 1.3 MGD when the weather is dry. During periods of wet weather, short duration inflows at a rate of up to 5 MGD can be expected due to storm water infiltration.

WASTEWATER TREATMENT The first step in the system is a continuously actuated conveyor-belt-type bar screen that removes large debris. The next step in the treatment process is uncommon in most wastewater treatment plants (WWTP): phosphorous removal. The influent flow has about 4 ppm phosphorous and the effluent has around 0.2 ppm, amounting to 99.5% removal efficiency. This is done by the five-stage Bardenpho process that uses volatile fatty acids (VFA) to encourage the uptake of phosphorous (P) by the microorganisms (bugs) in the nitrification basin. Diversion of wastewater to the VFA basins was a supplement to the original design, utilizing a screw pump to lift the wastewater to where the VFA are mixed with return activated sludge at the entry to a fermentation basin. In the fermentation basin, P is released by the microorganisms, only to be taken up in greater amounts in the nitrification basin. Following fermentation, mixed liquor is returned from the nitrification basin and the water flows into the first anoxic basin where nitrates are converted to nitrogen gas. In the nitrification basin, two 100-hp blowers aerate the water through fine-bubble diffusers, digesting nutrients and converting ammonia to nitrates. Two reclaimed water sprayers from a hydro-pneumatic system are used to knock down foam atop the nitrification basin where most of the P is removed from the wastewater. A secondary anoxic basin allows further conversion of nitrates to nitrogen gas and, after re-aeration by a single 40-hp blower through fine-bubble diffusers to prevent the secondary release of P, the water flows to secondary clarifiers where excess biosolids are removed. Wastewater from the secondary clarifiers passes through a series of dual-media sand filters. The backwash water from cleaning theslamps that sit directly in the flow of water. There are 30 bulbs in each of the 8 banks of lights; the bulbs are replaced every 2 years. The residence time in this system was estimated at 2.5 days.

Figure 1: Schematic of the Wastewater Treatment Facility in Payson, AZ Activated

 Sludge Re

turn 

Tertiary TreatmentSplitter

Box Secondary

Clarification

Headworks/Primary Treatment

Reclaimed Water

Effluent

Secondary Clarifier

Secondary Clarifier

Anoxic Basin 2

Mix

ed L

iquo

r R

ecyc

le

Anoxic Basin 1

Nitrification/ Aeration

Reaeration

Fermentation

Screw Pump

5-stage Bardenpho Process

Ultraviolet Disinfection

Influent

Comminutor

Grit Hauled to Landfill

Sludge Hauled to Landfill

Volatile Fatty Acid

Basins

Conveyor-Belt Bar Screen

Sand Filter

Sand Filter

Sand Filter

Grit Chamber

e filters is returned to the headworks. The final step in the process is disinfection via low intensity UV

The sludge removed from the secondary clarifiers is used in the manufacturing of fertilizer and some is recirculated to keep the bugs alive. The bio-solids enrichment and recycling (BER) process consisted of a dual belt-press to dewater the sludge before it is baked in a propane rotating dryer. By adding phosphoric acid and anhydrous ammonia to the sludge makes about 1500 lbs of pelletized fertilizer each day. This fertilizer was sold to local farmers, schools and golf courses at a loss of $900 per ton. This BER system was not large enough to support the amount of biosolids so hauling to the landfill has resumed, at a cost of $47/ton for solids taken to the landfill.

SYSTEM METRICS Electricity and natural gas usage for fiscal year 2007 were provided by The American Gulch Water Reclamation Facility. These data provide a snapshot in time of the operations at this facility. Occasional monitoring of a Parshall flume by operators provided an estimate of incoming wastewater flows. With these data, the metrics in Table 1 were computed.

Electricity Use Natural Gas Use

Annual Electricity Use

Annual Natural Gas Use

4.48-5.84 kWh/kgal

2.64-5.33 kWh/kgal

2.55 million kWh $215,300

72,800 Therms 2.13 million kWh

$172,200 Table 1: Wastewater Metrics in Payson, AZ

RECOMMENDATIONS/SUGGESTIONS Presented below are some best practice recommendations and suggestions as a result of additional qualitative analyses.

NO OR MINIMAL COST • Allow debris collected on the bar screen to rise only enough to expose more bar screen, letting excess water drip off before deposition in a

dumpster, reducing the water weight hauled to the landfill. • Operate the bar screen only every 15 minutes when freezing is not a threat. This could reduce the need for grinders as the bar screen is more

effective when more debris is collected on the screen. The grinders then could be used only during times when the bar screen is in motion and shortly afterward.

• Assess the balance between revenue and expenses. • Develop a cost analysis and implement capital improvement planning. • Implement water budgets and rate structures. • Understand how energy and water are utilized in the system. • Review system plans, specifications, and records before considering upgrades/improvements. • Involve plant operators and maintenance staff in the scoping, design and specification of future projects. • Assess costs of maintaining existing facilities versus upgrading over the expected life of the system. • Identify, evaluate, and reduce demand for heated or chilled water or air. • Secure operations and maintenance guides and training for staff when new systems/components are installed.

LOW TO MODERATE COST • Evaluate pumps, blowers, and motors for upgrade to either high-efficiency or VFD. • Store influent during the day when power demand peaks, and operate the facility at night. • Utilize blower room heat energy to keep biological activities warmer and possibly more reactive, to dry bio-solids in the fertilizer manufacturing

process, or to heat buildings in the winter. • Use high-efficiency ballasts and bulbs throughout the facility, especially in the UV disinfection process. • Implement water budgets and rate structures. • Adequately ventilate or sunshield all electrical and mechanical equipment in warm weather. • Utilize off-peak power usage strategies. • Create financial (or other) incentives for water customers to conserve instead of expanding plant capacity. • Identify and mitigate infiltrating storm water. • Create financial or other incentives for customers to conserve water and reduce wastewater production, instead of increasing plant capacity.

MODERATE TO HIGH COST • Design the UV disinfection system to be scalable to the amount of flow. This facility currently operates 3 of 4 light banks continuously. • Gravity feed all water movement throughout the treatment facility. • Utilize solar energy for use in drying of bio-solids by utilizing: photovoltaic cells; drying beds, or a greenhouse with proper ventilation. • Optimize treatment processes to reduce water and energy consumption. • Reduce friction/energy losses in pumps, fans, pipes, valves, and production wells. • Utilize renewable energy wherever possible throughout the wastewater system.

CONTACT INFORMATION Please contact the authors of the study with questions about the study, supporting data, and background information: Matt Roberts ([email protected]), Charlie Schlinger ([email protected]) or Steve Mead ([email protected]) at Northern Arizona University. For further information on the American Gulch Water Reclamation Facility, please contact Dave Millien by email: [email protected], or telephone: (928) 474-5257. Project Sponsor: Arizona Water Institute (http://www.azwaterinstitute.org/).

AN INVESTIGATION OF ENERGY AND WATER USE AT SLIDE ROCK STATE PARK, ARIZONA

By Matthew Roberts, Charlie Schlinger and Steve Mead Background Due to their often remote locations, Arizona State Parks frequently have unique challenges in supplying clean drinking water and treating wastewater. Slide Rock State Park in Oak Creek Canyon, Arizona, typifies this situation. The Arizona Water Institute (AWI) sponsored a study to develop a best practices guide for increasing efficiency and decreasing the overall energy and water use of rural Arizona’s water and wastewater systems and to identify those best practices appropriate for selected small systems through a series of case studies. Slide Rock State Park is located 21 miles south of Flagstaff and 6 miles north of Sedona along Highway 89A on a historic homestead and apple orchard. The historic homestead used a (now dilapidated and unused) flume to bring water from a higher elevation along Oak Creek to an orchard, which still exists and is now within the Park. The State Park continues the tradition of growing apples; so in addition to supplying clean drinking water to 240,000 visitors each year, the orchard is also irrigated as a part of Park operations.

WATER SUPPLY, TRANSMISSION, TREATMENT, STORAGE & DISTRIBUTION Raw water is drawn from Oak Creek, approximately 40 feet below and nearly 750 feet south of the Park’s water treatment facility. There are two submersible pumps at the creek, installed near the low-flow water surface, that draw surface water from the creek. Screens on the intakes exclude debris. One pump delivers water to the drinking water treatment plant, and the other supplies untreated water for irrigation. The irrigation pump runs once a week for 24 hours between May-September and once or twice for 24 hours in October. Water intended for potable use is pumped to a package treatment facility, which provides for: chlorination using sodium hypochlorite, alum addition, and filtration. From the filtration/clarification system, the treated water goes into a 40,000 gallon ground-set steel tank, which has enough capacity for the entire winter, but only enough for a month or so in summer. The filtration / clarification system operates at about 25-30 gallons per minute (gpm). This sand/carbon filter combination requires 1000 gallons of treated water for backwashing, the timing and / or pressure within the treatment system dictates when backwashing is required. The spent backwash water is used for irrigation of nearby

apple trees. Occasionally, backwashing is needed when there is insufficient treated water in storage, requiring water to be hauled in from Flagstaff, 20 miles away.

Figure 1: Slide Rock State Park in Oak Creek Canyon, AZ

Filter Backwash Water to Apple

Trees 40,000 gal StorageTreatment

Restroom Building

Raw Water from Oak Creek Raw Water Used for Irrigation of Historic

Apple Orchard

Office & Entrance Station

Slide Rock Market

Hydropneumatic Distribution

Figure 2: Water System at Slide Rock State Park, AZ When needed, water is drawn from the storage tank by a booster pump, which is housed in an adjacent building. At that time, residual chlorine (sodium hypochlorite) is automatically monitored and adjusted as necessary. System pressurization is provided by the combination of the booster pump and a hydropneumatic tank, which handles low/nuisance demands. The pressurization system consists of a 500 gallon hydropneumatic tank, two 2 hp booster pumps, and an air compressor. Pressurized potable water is then distributed throughout the Park.

There is currently no wastewater treatment facility at Slide Rock State Park. Wastewater from the single restroom building west of Oak Creek is collected in a holding tank and pumped out 2 or 3 times a year. Gray water from hand washing is disposed of in a leach field adjacent to the restroom building. There is also a second restroom facility between Oak Creek and Highway 89A with a similar holding tank arrangement with removal twice a year.

SYSTEM METRICS Water production and electricity usage data were collected from Slide Rock State Park and were used to estimate how much energy is used to treat and distribute a given volume of water. Three categories: potable water, irrigation water, and wastewater, were considered. The commonly used metrics of kWh/1000 gallons were developed for each category and tabulated in Table 1, below. The long distances involved in hauling wastewater yield an extremely high ratio of energy input (kWh) per volume (1000 gal) of wastewater.

Average Potable Demand

Average Irrigation Demand

Electricity Use-Potable

Electricity Use-Irrigation

Power Use-Wastewater

Annual Power Use-Water

Annual Power Use-Wastewater

215.5 kgal/year 590 gal/day 0.41 (gpm)

4.1 Mgal/year 11.2 kgal/day

7.75 gpm 5-7 kWh/kgal ~1 kWh/kgal

0 kWh/kgal, or 200-400 kWh/kgal

accounting for truck hauling

$7,500-$9,500 per year

$12,000-$15,000 per year

Mgal=million gallons, kgal=thousand gallons, gpm=gallons per minute

Table 1: Potable, Irrigation, and Wastewater Metrics at Slide Rock State Park

RECOMMENDATIONS/SUGGESTIONS Best practices for consideration at Slide Rock State Park vary in their cost or effort of implementation.

NO OR MINIMAL COST • Operate the backwash system in conjunction with the storage tank water level, allowing backwash to occur only when there is sufficient water to

do so, even if it means backwashing before it may be required. This may result in extra occasional water and energy expenditures due to premature backwashing, but this will eliminate the need to haul, at great energy and financial expense, potable water from Flagstaff.

• Assess the costs of maintaining existing facilities versus upgrading over the expected life of the system. • Review system plans, specifications, and records with plant operators, maintenance staff, and engineers before considering

upgrades/improvements. • Secure operations and maintenance guides and training for park staff when new systems/components are installed. • Assess the balance between revenue and expenses. • Understand how energy and water are utilized in the system.

LOW TO MODERATE COST • Evaluate pumps and motors for upgrade to either high-efficiency or VFD. Due to the infrequent use of these system elements, unless one of these

pieces of equipment is operating at extremely low efficiency, it would be advisable to upgrade only when equipment fails, or is near the end of its useful life.

• Implement a water conservation and education program. • Develop a cost analysis and implement capital improvement planning. • Retrofit facilities with energy efficient lighting, using high-efficiency ballasts and bulbs. • Provide a primary clarifier (gravity-driven grit chamber) so the filtration system could operate for longer periods between backwashing cycles. A

clarifier requires very little energy, and could save energy by reducing the need for backwashing, but requires significant capital investment. • Perform a water loss/leakage survey. • Evaluate off-peak power usage strategies. • Adequately ventilate or sunshield all electrical and mechanical equipment in warm weather.

MODERATE TO HIGH COST • Supply creek water via gravity flow from a higher elevation using a pipeline along the existing historic flume alignment. This would require about

a mile of new pipe/flume. • Consider additional system automation. • Reduce friction/energy losses in pumps, fans, pipes, and valves. • Build a wastewater treatment facility that generates high-quality effluent for use in irrigation. • Utilize renewable energy wherever feasible.

CONTACT INFORMATION Please contact the authors of the study with questions about the study, supporting data, and background information: Matt Roberts ([email protected]), Charlie Schlinger ([email protected]) or Steve Mead ([email protected]) at Northern Arizona University. For information on Slide Rock State Park, contact Steve Pace: [email protected] or Frank VanDevender: [email protected]. Project Sponsor: Arizona Water Institute (http://www.azwaterinstitute.org/) Photo Credit: C.M. Schlinger.