taking water efficiency to the limit

USGBC Illinois Chapter

November 1, 2011

Taking Water Efficiencyto the Limit

Presented by:Scott Bowman, P.E., LEED AP BD+CRob Young. P.E.

Slow the Flow

Learning Objectives1

• Feasibility factors of a rainwater capture system

• Evaluate LEED guidelines

• Comprehend system design through implementation

• Weigh pros and cons of rainwater capture

What’s the big deal?


• We turn on the tap and get water!


• But it takes1

Why should we care?

• Water is a undervalued resource, at least in the Midwest

• Potable water use is increasing at 2x the rate of world population growth

• 100 years ago, we used 10 gallons of water a day1today we use 100!

• Americans spend $523 on water per year, and $707 on soda!

Why should we care?

• Save some money

• Reduce pollution

• Reduce reliance on aging infrastructure

• Conserve energy

Why do we care?

• Freshwater supply in world

USGS

Circular

1268

USGS Circular 1268

Why do we care?

• Energy is used to deliver water

– Pump from source

– Treat to potable standards

– Distribute to use

– Desalination

– Waste water treatment

Why do we care?

• Water is linked directly to energy

– Cooling towers of power plants

– Direct cooling of power plants

– Scrubbing of plant discharge

– Oil recovery

– Bio>fuel production

• 8% of freshwater withdraw around the world is for power plants!

Why do we care?

• LEED is often invisible

• Energy efficiency is tough to visualize

• Water use is a common language

• Rainwater capture is a tangible benefit1you can see it!

• Every project needs a story1

LEED and Water Efficiency

LEED and Water Efficiency

• Some changes in v2009

• Not a major change in the way credits are calculated

• New prerequisite

• Baseline has been clarified, making credits more difficult to achieve

• Values changed, impact similar

Breakdown of v2.2

Breakdown of v2009

WEp1 Reduce by 20%

• First credit of v2.2 is now prerequisite

• This savings was so easy, it is now mandatory

• Baseline fixtures now defined by table in the standard

• Baseline lavatories are clearly now 0.5

gpm (rather than 2.5 gpm)

Water Use Reduction

WEc2 InnovativeWastewater Technologies

• Increased to 2 points

• Reduce generation of wastewater

• Reduce potable water use for sewage conveyance by 50%, or1

• Treat 50% of wastewater on site to tertiary standards

• Waterless urinals or composting toilets

WEc3 30>40% Reduction

• Now three levels up to 40%, first step

gains 2 points, 4 total possible

• Maximize water efficiency in buildings

• May be difficult to reach higher levels with only fixture selection

• Higher levels will require rainwater capture

Water Use Reduction

IDc1 45% Reduction

• Exemplary Performance ID credit

• Adds one more point

• Requires 45% reduction from baseline

• Waterless or ultra low urinals required

• Rainwater or Gray Water

Water Use Reduction

Pilot Credits

• PC10 – Sustainable Wastewater Management– Focus on innovative systems– Recovery and treatment– Reduces Threshold to 25%

• PC17 – Cooling Tower Makeup– Modification of EBOM credit– Controlled blowdown and filtration

• PC18 – Appliance and Process Water Use Reduction– Modification of LEED for Schools credit– Minimum performance for different equipment

LEED Healthcare

• WEc2 – Measurement and Verification

• WEc4.2 – Cooling Tower Makeup Water

• WEc4.3 – Food Waste Systems

• ID credits can be from different product)

LEED 2012?

• WEp1 – Landscape Water Use Reduction

• WEp2 – Minimum Fixture and Fitting Water Use Reduction

• WEp3 – Appliance and Process Water Use Reduction [PC18]

• WEc1 – Additional Landscape Water Use Reduction

LEED 2012?

• WEc2 – Additional Fixture and Fitting Water Use Reduction

• WEc3 – Sustainable Wastewater Systems [PC10]

• WEc4 – Cooling Tower Makeup Water [PC17]

• WEc5 – Additional Appliance and Process Water Reduction

Water Efficient Design


• Thought process for reducing water usage.

1) Baseline(Demographics / Usage)

2) Conserve (Fixture Selection)

3) Generate (Reclaim, store, treat, and distribute Rainwater, Graywater, Condensate, Subsoil Drainage)

FTE’s

Demographics

Usage

Fixture Types

Human Waste

Rainwater Capture

Total Water

Rainwater Capture


• Usage for a variety of occupants


• Once it has been determined that rainwater capture is necessary:

– Refine goals.

– Define cistern size.

– Iterate with goals to determine proper size and type.

– Determine diagrammatical layout, equipment, and treatment.

Rainwater Capture

Goals > %

Cistern Size/Type

Pumps / Piping

Treatment

Demographic Affect

– Note: based on % female occupancy

LEED NC v2.2WEc2 Calculation

LEEDNC v2.2WEc2Calculation

LEED NC v2.2WEc2 / WEc3 Calculations

Note that this drops to 43.2% under LEED v2009!

Fixture Selection

• Which fixtures contribute the most?

– Based on WEc3 – total water usage

– Assumes 50/50 gender distribution

Baseline Water

Usage

Percentage

of Total Use

Lowest Possible

Water Usage

Potential for

Savings

Urinals 1.0 22% 0 21.6%

Men's Water Closets 1.6 17% 1.28 3.5%

Women's Water Closets 1.6 52% 1.1/1.6 10.8%

Lavatories 0.5 6% 0.5 0.0%

Sinks 2.5 1% 2.2 0.2%

Mop Basins 2.5 1% 2.5 0.0%

Total 36.1%

Fixture Selection

• Lavatories: 0.5 gpm base, 15 second use

– Sensor faucets save additional 20% (12 second use rather than 15 second)

• Sinks: 2.5 gpm base

– Standard 2.2 gpm faucets save 12%.

• Showers: 2.5 gpm base

– Many options available. Beware of performance!

Fixture Selection

• Urinals – 1.0 gpf base

– Waterless Urinals

• Save 100%

– 1/8 gpf urinals

• Save 87.5%

• Sensor only

– 1/2 gpf urinals

• Save 50%

• Manual / Sensor

Fixture Selection

• Water Closets – 1.6 gpf base

– Dual Flush

• 1.1 / 1.6 gpf

• Save 21%

• Manual / Sensor

– Low Flow

• 1.28 gpf

• Save 20%

• Manual / Sensor

• Requires special bowl

Fixture Selection – Cost

• Lavatories, battery operated

– 2.0 gpm lavatory

• $365

– 0.5 gpm lavatory

• $350


• Urinals, battery operated sensors

– 1.0 or 0.5 gpf

• $460

– 1/8 gpf

• $495


• Water Closets, battery operated sensors

– Standard Flush – 1.6 gpf

• $395

– Dual Flush – 1.6/1.1 gpf

• $426

– Low Flow – 1.28 gpf

• $400

Rainwater Capture Design

• Rainwater Capture – What’s the big deal?


• Cistern sizing – what’s the big deal?

– Inputs

• Monthly Rainfall – how many events per month?

• Other inputs (subsoil, condensate, site, etc)

• How much water can be captured?– Roof capture coefficients

– Filter efficiencies

– Outputs

• Daily usage

• Overflow


• Cistern sizing – what’s the big deal?

– Other uses

• Irrigation (Landscape Architect)

• Stormwater Detention (Civil Engineer)

– The mechanical engineer cannot size cisterns for these types of systems.

• Conclusion – not just a tank in the ground!


• Storage is dynamic


Material List

• Roof Drains

• Pre>Filters

• Cisterns

• Intake Filters

• Pumps

• Final Filters

• Final Treatment

• Day Tank

• Makeup Water

• Level Sensors

• Booster Pumps

• Meters

)following a drop of water


Pre>Filter Options

Stark Industries JR Smith / RMS –Vortex Filter


• Cisterns

– Concrete

• Poured

• Pre>fabricated


• Cisterns

– Concrete

• Poured

• Pre>fabricated

– Polyethylene


• Cisterns

– Concrete

• Poured

• Pre>fabricated

– Polyethylene

– Fiberglass


• Cisterns

– Concrete

• Poured

• Pre>fabricated

– Polyethylene

– Fiberglass

• Intake Filters


Inside Building

• Pumps

• Final Filters

• Final Treatment

– Ozone

– Chlorination

– High>efficiency filters

– UV

Ozone by Nature

Ozone by Man


Distribution

• Day Tank

• Makeup Water

• Level Sensors

• Booster Pumps

• Metering


Indoor equipment for reclaimed flushing


• Hydraulic implications

– Adding two sets of pumps

• Reclaim Pumps (cisterns � treatment � day tank)

• Booster Pumps (to distribute to flush valves)


• Multiple Levels of Metering

– Main Meter

– Sanitary Add

• Flushing Reclaim

– Sanitary Deduct

• Irrigation Makeup


• Other types of water to consider for re>use

– Subsoil drainage

– Cooling coil condensate

– Gray water (possibilities exist for 5>25% savings depending on lavatory and shower selections)


• Code implications– Get the code officials involved early – this is new to

most of them.

• Uniform Plumbing Code – Chapter 16– No direct connection to any potable water system

– Building and equipment room signage

– Pipe and equipment labeling

– Tank>type water closets

Rainwater Capture Practice

• Keeping the Cisterns Clean

– Pre>Filters

– Aeration

– Chlorination

– Natural (Biofilm)


• Packaged Systems now Available

Case Study

Wellmark BCBS

Wellmark BCBS

• HOK

• RDG Planning & Design

• Snyder Associates

• KJWW Engineering

• The Weitz Company

• Baker Group

• Baker Electric

• The Weidt Group

Wellmark BCBS

Wellmark BCBS

• Office building

– 603,980 GSF Office Building

• 5 levels above grade

– 500 car below grade parking

• 2 parking levels below grade

• 115,000 GSF roof

Wellmark BCBS

Wellmark BCBS

• Multipurpose building

– 35,000 GSF fitness center

• 2 levels above grade

– 5,500 GSF Central plant

– 1647 car parking structure

• 10 levels above grade, ½ level below

Wellmark BCBS

Wellmark BCBS

• 48.2 kBtu/sf/year

– 33.8% better than ASHRAE 90.1 –2004 (30.8% cost)

• LEED NC v2.2

Platinum!

– 53 of 69 points

• 5.6 acre urban site

Wellmark BCBS

• 2,330 full time equivalents

– Established for LEED and Design purposes

• 70/30 split women to men

• Current Water Modeling:

– 55.8% reduction in human water flushing

– 57.9% reduction in total water use

• 8,000 gallons per day required for flushing

Note that all values related to this project are for design purposes

based on averaged historical data. Actual performance cannot

be confirmed until after final construction and commissioning.

LEED WEc3 Distribution

Total Water Use

Wellmark BCBS

Total Water Use

Wellmark BCBS

• Achieved 7 LEED points related to Water– SSc6.1 – 1 point

• Stormwater Detention (integrated into system)

– WEc1 – 2 points• No water use for irrigation

– WEc2 – 1 point• Greater than 50% reduction in wastewater flushing

– WEc3 – 2 points• Greater than 30% reduction in water use

– IDc1 – 1 point• Exemplary performance, Greater than 40% reduction in

water use

Wellmark BCBS

• Fixture Selections:

– Sensor lavatories 0.5 gpm

– Sensor low flow urinals 0.5 gpf

– Sensor dual flush toilets 1.6/1.1 gpf (women)

– Sensor toilets 1.6 gpf (men)

• All sensors are battery powered

Wellmark BCBS

• Detailed system costs

Fixture QTY Cost % QTY Cost %

Dual Flush water closests 96 $445.00 1.15%

1.6 gpf water closets 49 $425.00 0.56% 145 $425.00 1.67%

0.5 gpf urinals 31 $465.00 0.39% 31 $465.00 0.39%

0.5 gpm lavitories 87 $78.00 0.18% 87 $68.00 0.16%

Total Fixture costs 2.29% 2.22%

Fixture cost difference 0.08%

Wellmark building Baseline building

Plumbing fixture comparison from Percent of Plumbing

Wellmark BCBS

• Cistern Size:

– 112,000 gallon Irrigation/Detention

• 52,000 gallons for Detention

• 60,000 gallons for Irrigation

– 60,000 gallon Flushing

• 2 x 3,500 gallon Day Tanks

• 130 gpm Flushing Booster Pump

• 100 gpm Irrigation Booster Pump

Wellmark BCBS

• Storm water detention

– Irrigation cistern also used for detention

– Added complexity to keep 52,000 gallons free for detention

Wellmark BCBS

• Wellmark Cisterns

Wellmark BCBS

Wellmark BCBS

• Lessons Learned

– Possibility of combining rainwater detention and reclaimed rainwater storage

– Water Purity Standards

• Coliform Bacteria– Diarrhea/Dysentery Symptoms

• Turbidity Units (NTU)– Higher risk of gastrointestinal diseases

– Protects bacteria from UV treatment

– Elevations!


• Lessons Learned

UV Treatment

Wellmark BCBS

• Mechanical Site Work

• Piping cost would normally be

in site budget

Material Labor Total

1.07% 0.25% 1.31%


0.75% 0.16% 0.91%

2.23%Total cost for site and cistern piping and pre-filters

Mechanical Site Work as Percent of Site

Underground site piping

Vault pre-filters and piping

Wellmark BCBS

• Reclaimed Water System Costs

Less than 0.8% Mechanical Budget


Reclaim water pumps 0.14% 0.08% 0.22%

Reclaim tank 0.41% 0.07% 0.48%

Pressure booster pump 1.33% 0.06% 1.39%

Meters/solenoid valves 0.06% 0.02% 0.08%

Total 2.17%

Irrigation System Costs as Percent of Plumbing


Reclaim water pumps 0.14% 0.08% 0.22%

Final filters 0.11% 0.07% 0.18%

Ozone generator 0.68% 0.06% 0.74%

Reclaim tank 0.41% 0.07% 0.48%

Pressure booster pump 0.51% 0.06% 0.57%

Meters/solenoid valves 0.09% 0.02% 0.11%

Total 2.31%

Flushing System Costs as Percent of Plumbing

Wellmark BCBS

• And the grand total is1

Less than 0.5% of Total Construction!

1.90%

0.91%

Flushing system costs 0.41%

Irrigation system costs 0.38%

Plumbing fixture premium 0.01%

Misc piping/labels/valves 0.19%

3.81%

Perecent of Mechanical for Reclaim Water System

Total

Cistern piping/pre-filter cost

Flushing Cistern

Wellmark BCBS

Wellmark BCBS

• Cost of Saving Water

Wellmark BCBS

• Wellmark will1

– Save 7,200 gallons of water a day

– Will not discharge 1,550,000 gallons of sewage

– Save 2,600,000 gallons of water a year

• Enough to fill four Olympic sized pools each year

Wellmark BCBS

• Or thinking of a standard water cooler1

• 1435 Water Cooler Bottles a Day

• 520,000 Bottles a year!

Thank you!

Slow the Flow

Credits and Resources

• Virginia Rainwater Harvesting Manual– www.cabellbrandcenter.org

• Rainwater Management Solutions– www.rainwatermangement.com

• JR Smith– www.jrsmith.com

• Wade/Hydromax– www.hydromax.com

• Stark Environmental– www.starkenvironmental.com