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MSA PROFESSIONAL SERVICES, INC. | More ideas. Better Solutions. © 2014 by MSA Professional Services

Presentation prepared for: Wisconsin Wastewater Operator Association 2015 Wisc. Dells October 8th, 2015 | Mark Lundgren

Phosphorus Removal Going from 1 ppm to 0.075 ppm in

Cumberland, WI


What is your current P Limit?


Cumberland, WI

Population: 2,152 Phosphorus Effluent Limit: 0.075 mg/l


Agenda » State of Nutrient Regulations + Policy » Cumberland WI Story » Q & A


Nutrient Pollution – Why Care?


Children playing in cyanobacterial bloom


What does that mean for my plant?


PERMIT


Why low limits in WI?


Wisconsin Level

» 2009 - Environmental Groups file lawsuit » 2010 – EPA Sends warning to WDNR to adopt

new phosphorus standards by 2010 and nitrogen standards by 2013

» Dec 1, 2010 WI Phosphorus Water Quality Standards updated • Created water quality standards in surface waters • WPDES permits issued to point sources • Tightened Ag performance standards

» 2012 EPA approves WI phosphorus program


National Level - EPA Lawsuit » 2005 – Mississippi River Collaborative (MRC) is formed.

• Includes Minnesota Center for Environmental Advocacy » 2008 – MRC files petition to force EPA to act on

hypoxia. » 2011 – EPA denies petition. » 2012 – MRC files lawsuit against EPA denial. » 2013 – Court rules for MRC. EPA must respond to

original hypoxia petition in 6 months. » 2013 – EPA appeals court decision. Granted stay of

deadline to respond. » More to come . . . .


Comprehensive National Mississippi Nutrient Regulations

Coming?


Cumberland WWTP - Existing


Cumberland WI WWTP - Phosphorus

» Design Flow 0.4 MGD » Typical Flow 0.18 MGD » No major upgrade since 1980 » Current Plant Effluent Average

• 9 lbs / day total P (2.7 mg/l) » Previous Permit

• 1 mg/l P (1,218 lbs total per year) • City did NOT meet limits • Participated in Red Cedar River Phosphorus Trading

Program 2 to 1 trade with Ag Sources ~4000 lbs /yr trade (~$16,000 per year in payments)


2010 WDNR Phosphorus Rules

» Added Water Quality Based Effluent Limit (WQBEL) to TMDL for Hay River

» New limit 0.075 mg/l P (91 lbs / yr) • City would have to offset 3,200 lbs / yr through

trading

» Two options for offsetting P: • Adaptive Management • P Trading


P Trading

» Trading reduced to upstream only partners in 2010 rules update


Adaptive Management

» Adaptive management requires 5:1 trade • 16,000 lbs/yr would need to be offset to meet

permit • $64,000 / yr in offsets $1.2 million over 20 year lifespan

• Improvement in instream P levels MUST be seen over 10 year permit cycle No guarantee for no further action

» Neither P Trading or Adaptive Mgmt works for Cumberland


How to meet 0.075 mg / L P Limit?

» “Typical” Influent = 4.0 – 12.0 mg/L » Some P is removed in biological treatment process

• About 2% of cell biomass is phosphorus • Ponds & Lagoons = less TP removed • Activated sludge = more TP removed

2005 MPCA study of 59 activated sludge treatment plants found an average removal of 47%

» Cumberland RBC poor P removal efficiency • ~25% removal of influent P • 20+ years old

» Cumberland needs additional P treatment


Decision Time

» City decides to go for upgrade • High cost of payments to farmers • No guarantee that adaptive management will

meet permit requirements

» Options to meet limits • Oxidation Ditch w tertiary filter • Membrane Bioreactor


Oxidation Ditch Pros: Easy to Operate. Less Cost. Less Equipment.

Cons: Provides 1mg/l P in Effluent. Provides 0.5 mg/l P with Chemical Addition. Requires Additional Treatment.


» Physical Barrier » Small pores (5 - 10 um) » Compact footprint » TP = ~ 0.10 mg/L » 0.075 mg/L achievable

Cloth Media Filtration

Presenter

Presentation Notes

Filtration Mode • Inlet wastewater enters filter • Cloth media is completely submerged • Disks are stationary • Solids deposit on outside of cloth media forming a mat as filtrate flows through the media • Tank liquid level rises • Flow enters the filter by gravity and filtrate is collected inside the disks and discharged • Heavier solids settle to tank bottom Backwash Mode • Solids are backwashed at a predetermined liquid level or time • Backwash shoes contact the media directly and solids are removed by vacuum pressure of the backwash pump • Two disks are backwashed at a time (unless a single disk is utilized) • Disks rotate slowly • Filtration is not interrupted • Backwash water is directed to headworks Solids Wasting Mode • Heavier solids on the tank bottom are removed on an intermittent basis • Solids are pumped back to the headworks, digester or other solids collection area of the treatment plant


» Deep Bed Sand

Filters » Filtration of TP » Filtration +

Adsorption • Can add Hydrous

Ferric Oxide (HFO) Coating to sand to gather more P

» Larger footprint » TP = ~ 0.05 – 0.10

mg/L » 3 ft headloss per

filter » 6 ft headloss in

series

2-Stage Upflow Sand Filtration

Presenter

Presentation Notes

Influent enters the center of the filter through a central feed chamber. The central feed chamber has a series of radial arms to evenly distribute the influent flow to the media bed near the bottom of the filter. As the water flows upward through the filter media suspended and colloidal solids are removed. Filtrate exits the filter near the top and flows over a fixed weir plate that maintains a constant level. The solids that are captured in the filter media are drawn downward into a recessed chamber located below the lower cone by the suction of the airlift pump. The high energy, turbulent upward flow inside the airlift provides a scrubbing action that effectively separates the sand and the captured solids before discharging them in the washbox at the top of the filter. The washbox is a baffled chamber that allows for counter-current washing and gravity separation of the filter media and the captured solids. Media cleaning is accomplished utilizing filtered water from the upper chamber of the filter. Regenerated filter media is returned to the top of the filter bed as it falls by gravity from the counter-current washer. An adjustable V-notch weir directs the reject flow out of the filter carrying concentrated captured solids to a suitable disposal point.


Pros: Effluent 0.075 mg/l P. Modular Units. No Additional Treatment Needed. Flexibility for Future Regs.

MEMBRANE BIO REACTOR (MBR)

Cons: Higher Cost. Proprietary. More Equipment, Single Source Vendor. “New” Technology.


» Greatest Degree of Solids Separation » MicroFiltration (MF)

• 0.1 – 3.0 um » UltraFiltration (UF)

• 0.01 – 0.1 um

Membranes


» TP < 0.05 mg/L » Small Footprint » Energy Intensive » Typically not gravity flow

• Permeate suction pumps

Membranes


» Operate at elevated MLSS » Membranes used instead of final clarifiers » Metal Salt addition to MLSS ahead of membranes » TP < 0.05 mg/L possible » Requires excellent (redundant) fine screening

• < 3 mm (0.12 in)

Membrane Bioreactors (MBRs)


Cumberland WWTP Cost Analysis: Cost Consideration

Oxidation Ditch W Tertiary Filter Membrane Bio Rector

2014 Capital Cost $1,582,000 $2,196,000

2019 Capital Cost $600,000 $223,000

2015-2025 Annual O&M Cost $49,000 $49,000

2025-2035 Annual O&M Cost $49,000 $49,000

Total Cost 2015 thru 2035 $3,320,000 $3,396,000


» Enhanced Biological Phosphorus Removal » Chemical Addition (Optional) » MBR » Total P = 0.03 mg/l (Modeled)

What are we doing in Cumberland?

MBR MBR

Anoxic

Anaerobic

INFLUENT

EFFLUENT

FINE SCREENS

CHEMICAL ADDITION

CHEMICAL ADDITION


» Capital Cost Similar to Oxidation Ditch with Tertiary

Filter » More reliable effluent quality » More flexibility to meet future regulations

Main Reasons for MBR


Ovivo Membrane System


» $7.6 Million Upgrade

• New screening • New MBR Building • Misc Equipment Replacements • Anaerobic Digesters Aerobic Digesters

» Average Residential User Charge for Cumberland • $39.25 $55 / month (40% increase)

Cost?


Thank You! Questions?


National Nutrient Regulation

» EPA • Gives states technical guidance to states on how

to deal with nutrient pollution • Helps States develop water quality criteria for

incorporating nutrient regulations into state policy • Helps States develop TMDLs (Total Maximum Daily

Load) allocations for nutrients

» States • Figure out the details and implementation


Minnesota – Watershed Approach » Step 1. Monitor water

bodies and collect data » Step 2. Assess the data » Step 3. Develop strategies

to restore and protect the watershed's water bodies

» Step 4. Conduct restoration and protection projects in the watershed

Wisconsin Approach very similar . . .


» Use a “ballast”

• Create ‘heavy’ floc • Micro-Sand/Lamella Clarifier • Magnetite/Circular Clarifier

» Fast Settling • Small Footprint

» Capture and Reuse Ballast » Fair amount of moving parts » TP = ~0.05 – 0.1 mg/L » Many demonstration tests

in WI (2012-2014) • < 0.05 mg/L achievable

» ~ 1 ft headloss

Ballasted Clarification


Ballasted Clarification


» Adsorption-enhanced

filtration may yield lower chemical use

» Hydrous Ferric Oxide (HFO) Coating • P is adsorbed onto sand • HFO and P abraded

during backwash • Sand re-charged with

HFO

Reactive Upflow Sand Filtration

Presenter

Presentation Notes

HFO = Hydrous Ferric Oxide floc; scanning electron microscopy – X-ray fluorescence


Coagulation Tank Contents


Flocculation Tank Contents


» Dose coagulant after secondary clarifier, ahead of filter » Rapid Mix » Coagulation » Flocculation » Add Polymer at Flocculation Stage

Cloth Media Filtration – Flow Diagram


» Goal

• Convert phosphorus to a form that can be separated from the final effluent (settling or filtration)

» How?

• Chemical addition to make dissolved P settleable or filterable

• Biological Treatment to Increase P in waste sludge • Advanced P Removal Technologies

Additional P Removal


Options for Cumberland


Phosphorus Speciation (Effluent)

» Soluble Reactive P • “Reactive” with metal salts to form precipitate

» Soluble Non-reactive P • Passes through treatment • Typically small fraction (0.01 – 0.03 mg/L)

Ortho-P

Total Phosphorus (TP)

Soluble Reactive P (sRP)

Soluble Non-reactive P (sNRP)

Colloidal P

Particulate P


» Add a metal salt to bind with soluble reactive phosphate

• Calcium-based (lime) • Iron-based (Ferric Chloride, Ferrous Sulfate) • Aluminum-based (Alum, Polyaluminum Chloride)

Chemical Phosphorus Removal


» The lower you go, the greater the dosage rate

required • Need greater chemical concentration in water to “find” the

remaining phosphorus

» Molar Ratios (moles of metal:moles of Phosphorus) • 5 mg/L 0.8 mg/L : Molar Ratio ~ 1.2:1 to 1.5:1 • 0.8 mg/L 0.5 mg/L: Molar Ratio ~ 1.5:1 to 3.5:1 • 0.5 mg/L 0.2 mg/L: Molar Ratios ~ 3.5:1 to 10:1 • 0.2 mg/L 0.04 mg/L: Molar Ratios ~10:1 to >30:1



Molar Ratios Getting from 6 mg/L to 0.8 mg/L


Molar Ratios Getting from 0.8 mg/L to 0.4 mg/L!


» Inject at head of primary and/or secondary clarifiers

• Well-mixed area yields best results

» Chemically bound TP solids are settled and removed » Typical Dosing Molar Ratios (Metal:TP) = 1.2 to 2.0 » Final effluent TP = 0.5 mg/L » Increased sludge production from chemical addition



» Create conditions to grow specific biomass (PAO’s)

• Cycle between anaerobic and aerobic phase • PAOs consume VFAs and release stored polyphosphate in anaerobic conditions, building up

carbon reserves • In aerobic conditions, PAOs multiply and take up more phosphate than was released in the

anaerobic phase • RAS returns the PAOs to the anaerobic stage to build up the population and keep the process

running

Biological Phosphorus Removal


» Need specific influent conditions for Bio-P

• BOD:P Ratio = 15:1 to 25:1 (the higher the better) • Enough Volatile Fatty Acids (VFAs) for PAO’s to compete

with other biology

» Final effluent TP = 0.4 mg/L to >1.0 mg/L

» Upsets common in some facilities » Effluent TSS must be kept low

Biological Phosphorus Removal


ARGGGG!!!! (Bored Yet???)


Cumberland WWTP 4 Phosphorus Considerations: DNR REQUIREMENTS: Oxidation Ditch: MBR: 2016 Establish Effluent P 2015 MBR On-line *2017 P = 1mg/l No P Trading *2016 Meet 0.075 mg/l P 2018 P Options: Review Filtration, Storm Water, MBR, Bio P with Chemicals, Trading in Effluent 2019 Implement Option: e.g. MBR or Trading * Based on 9/3/13 correspondence with Kathy Bartilson @DNR


It’ll get better…


» Filtration or equivalent

• Tertiary or “Add-on” processes

• Downstream of secondary treatment

» Same principles apply! • Add metal salts • Create particulate P from

remaining sRP and colloidal P • Confine by a physical barrier

or settle out

» Low TP limits require very low effluent TSS

Advanced Phosphorus Removal

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http://www.dreamstime.com/royalty-free-stock-photography-phosphate-molecular-structure-image21404687&ei=SgX-VOW1KcX2UIPKgvgO&bvm=bv.87611401,d.aWw&psig=AFQjCNHIidTaFOlDJfTgEV_gCmvZHP254g&ust=1426020026736200


» Cloth Media Filtration (pile cloth, micro-screens)

» Sand Filtration (2-stage upflow, 2-stage reactive) » Membrane Filtration (microfiltration, ultrafiltration,

MBR)

Advanced Phosphorus Removal


» How Strict* is your Limit?

• 0.5 – 1.0 mg/L – “standard” Chem-P, EPBR, EPBR + Chem P • 0.3 – 0.5 mg/L – sand filtration, CMF • 0.3 – 0.1 mg/L – CMF, 2SUSF • 0.075 – 1.0 mg/L – CMF?, R2SUSF • 0.04 - 0.075 mg/L –R2SUSF, 2SUSF, MF, UF, MBR • <0.040 – R2SUSF, UF, MBR, RO

What Technologies to Consider?

CMF = Cloth Media Filtration MF = Microfiltration

2SUSF = 2 Stage Upflow Sand Filtration UF = Ultrafiltration

RO = Reverse Osmosis MBR = Membrane BioReactor

EBPR = Enhanced Biological Phosphorus Removal Chem-P = Chemical Phosphorus Removal

R2SUSF = Reactive 2 Stage Upflow Sand Filtration *Limits and corresponding technologies indicated are the author’s opinion. They are provided as a possible starting point for evaluation and cost effectiveness determination.

phosphorus removal - wwoa conference... · msa professional services, inc. | more ideas. better...

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