Refinement of Nitrogen Removal from Municipal Wastewater Treatment Plants Prepared for Maryland Department of the Environment Presented by: Gannett Fleming, Inc. Stephen B. Gerlach, PE & Carrie DeSimone In partnership with George Miles Buhr, LLC
What is ENR? What is ENR? What is ENR? What is ENR? � Enhanced Nutrient Removal Enhanced Nutrient Removal Enhanced Nutrient Removal Enhanced Nutrient Removal � � Reduce nutrient discharges from Reduce nutrient discharges from Reduce nutrient discharges from WWTPs WWTPs WWTPs Reduce nutrient discharges from WWTPs � � Use of state Use of state Use of state- -of of of- -the the the- -art microbial technology to break art microbial technology to break art microbial technology to break Use of state of the art microbial technology to break � down nitrogen before discharge down nitrogen before discharge down nitrogen before discharge down nitrogen before discharge � Next step from BNR Next step from BNR Next step from BNR Next step from BNR �
Biological Nutrient Removal Program Biological Nutrient Removal Program Biological Nutrient Removal Program Biological Nutrient Removal Program (BNR Program) (BNR Program) (BNR Program) (BNR Program) � Implemented in 1983 by the Maryland Department of Implemented in 1983 by the Maryland Department of Implemented in 1983 by the Maryland Department of Implemented in 1983 by the Maryland Department of � the Environment (MDE) the Environment (MDE) the Environment (MDE) the Environment (MDE) � Included 66 plants of capacity Included 66 plants of capacity Included 66 plants of capacity ≥ 0.5 MGD 0.5 MGD Included 66 plants of capacity ≥ 0.5 MGD 0.5 MGD � � Plants retrofitted to achieve total nitrogen limits of 8 mg/l Plants retrofitted to achieve total nitrogen limits of 8 mg/l Plants retrofitted to achieve total nitrogen limits of 8 mg/l Plants retrofitted to achieve total nitrogen limits of 8 mg/l � � Goal was 40% reduction of nutrients to Chesapeake Bay Goal was 40% reduction of nutrients to Chesapeake Bay Goal was 40% reduction of nutrients to Chesapeake Bay Goal was 40% reduction of nutrients to Chesapeake Bay � (Bay) (Bay) (Bay) (Bay) � Have exceeded this goal Have exceeded this goal Have exceeded this goal Have exceeded this goal � � Actual reductions from 1985 levels=16.9 million pounds Actual reductions from 1985 levels=16.9 million pounds Actual reductions from 1985 levels=16.9 million pounds Actual reductions from 1985 levels=16.9 million pounds �
Purpose of Enhanced Nutrient Removal Study Purpose of Enhanced Nutrient Removal Study Purpose of Enhanced Nutrient Removal Study Purpose of Enhanced Nutrient Removal Study (ENR Study (ENR Study – – 2002 2002 2002 – – 2004) 2004) 2004) (ENR Study (ENR Study 2002 2004) � Clea Clea Clear evidence p r evidence plants could exceed 8 mg/l ants could exceed 8 mg/l Clear evidence p r evidence plants could exceed 8 mg/l ants could exceed 8 mg/l � � EPA/ EPA/ EPA/MDE/ MDE/Loc Local Go l Gove vernments looking to rnments looking to achie achieve further nitro e further nitrogen en EPA/MDE/ MDE/Loc Local Go l Gove vernments looking to rnments looking to achie achieve further nitro e further nitrogen en � reductions cost effectively reductions cost effectively reductions cost effectively reductions cost effectively � Enhancement of BNR Program in c Enhancement of BNR Program in c Enhancement of BNR Program in compliance with amended 200 mpliance with amended 2000 Enhancement of BNR Program in compliance with amended 200 mpliance with amended 2000 � Chesapeake Bay Agreement by furt Chesapeake Bay Agr ement by further reducing nutrients to the Ba her reducing nutrients to the Bay y Chesapeake Bay Agr Chesapeake Bay Agreement by furt ement by further reducing nutrients to the Ba her reducing nutrients to the Ba � GF/GMB asked to evalua GF/GMB asked to evaluate 20 of the larg GF/GMB asked to evaluate 20 of the largest est WWTPs WWTPs WWTPs in MD in MD in MD GF/GMB asked to evaluate 20 of the larg te 20 of the largest est WWTPs in MD � � Ev Ev Evalua aluate alternative te alternatives for re for redu ducing nitrogen in WWTP effluent cing nitrogen in WWTP effluent Evalua aluate alternative te alternatives for re for redu ducing nitrogen in WWTP effluent cing nitrogen in WWTP effluent � � Develop c Develop cost estimate for alternatives Develop c estimate for alternatives Develop cost estimate for alternatives estimate for alternatives � � Extrap Extrap Extrapolate cost estimate to 6 Extrapolate cost estimate to 6 olate cost estimate to 66 plants in BNR Program which olate cost estimate to 66 plants in BNR Program which plants in BNR Program which plants in BNR Program which � helped establish newly enacted flush tax helped establish newly enacted flush tax helped establish newly enacted flush tax helped establish newly enacted flush tax
Conococheague WWTP Cumberland WWTP Westminster WWTP Sod Run WWTP City of Frederick WWTP Hagerstown WPCP Freedom District WWTP Back River WWTP Ballenger Creek Cox Creek WRF WWTP Parkway Little Patuxent WRF WWTP Seneca Annapolis WRF WWTP Bowie Piscataway WWTP WWTP Hurlock WWTP City of Cambridge WWTP Salisbury Marley Taylor WRF WWTP
Current Process Current Process Current Process Current Process RATED FLOW PLANT EXISTING BNR PROCESS (MGD) MLE Cambridge 8.1 Seneca MLE 20 Piscataway Step Feed 30 Bardenpho (4-Stage) Parkway 7.5 Annapolis Bardenpho (4-Stage) 13 Ballenger 6 A 2 O Marley-Taylor Schreiber System 6 MLE 3.5 Freedom District Johannesburg L. Patuxent 22.5 Cumberland Step Feed 15 Sod Run 20 A 2 O Modified Westminster 5 MLE/A 2 O Hagerstown Modified Johannesburg 8 Conococheague MLE 4.1 A 2 O Frederick 7 VT 2 Bowie 3.3 Cox Creek MLE 15 Back River MLE 180 Salisbury Submerged (A 2 O) Trickling Filter 8.5 Bardenpho (4-Stage) Hurlock 1.65
Phase I Phase I Phase I Phase I Approach Approach Approach Approach � Phase I (20 Phase I (20 Phase I (2002- -2003): 2003): 2003): Evaluate ways to cost Phase I (2002 2003): Evaluate ways to cost effectively reduce N in Evaluate ways to cost effectively reduce N in Evaluate ways to cost effectively reduce N in effectively reduce N in � plant discharges plant discharges plant discharges plant discharges � Primary considerations in developing alternatives Primary considerations in developing alternatives Primary considerations in developing alternatives Primary considerations in developing alternatives � � developed biological models at ea developed biological models at ea developed biological models at each facility to estimate nitroge developed biological models at each facility to estimate nitroge ch facility to estimate nitrogen ch facility to estimate nitroge n n n � removal capacity remov removal capacity remov l capacity l capacity � determined tank (reactor) volume determined tank (reactor) volume determined tank (reactor) volume requirem requirements ents for each plant uti for each plant utilizing lizing lizing determined tank (reactor) volume requirem requirements ents for each plant uti for each plant uti lizing � industry s industry standards industry s industry standards andards and andards and and individual plant data and individual plant data individual plant data individual plant data � site constraints site constraints site constraints site constraints � � existing plant configuration existing plant configuration existing plant configuration existing plant configuration � � cost effectivene cost effectivene cost effectiveness of alternatives cost effectiveness of alternatives ss of alternatives ss of alternatives � � Needed one or two processes that were proven and reliable Needed one or two processes that were proven and reliable Needed one or two processes that were proven and reliable Needed one or two processes that were proven and reliable �
Breakdown of BNR Processes in Maryland Phase I Challenge Step Feed 1% 1% 3% Trickling Filter 1% 3% 1% 25% MLE RBC 6% 6% Bardenpho Schreiber 3% A2O 6% 7% Lagoon 1% 3% Activated Sludge Overland 15% 1% 6% 1% 6% Methanol Addition Oxidation Ditch
Biological Nitrogen Removal Biological Nitrogen Removal Biological Nitrogen Removal Biological Nitrogen Removal Nitrogen Cycle Nitrogen Cycle Nitrogen Cycle Nitrogen Cycle ENR process takes ENR process takes additional time and additional time and requires additional tank requires additional tank volume beyond BNR. volume beyond BNR.
Modified Modified Ludzack Ludzack Ludzack- -Ettinger Ettinger Ettinger Modified Modified Ludzack Ettinger (MLE Process) (MLE Process) (MLE Process) (MLE Process) Anoxic Internal Recycle Oxic RAS Clarifier WAS Cox Creek WRF, Anne Arundel Co. 15 mgd
A 2 O Process O Process A 2 O Process O Process Anaerobic Anoxic Internal Recycle Oxic RAS Clarifier WAS Sod Run WWTP, Harford Co. 20 mgd
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