JB Neethling HDR Engineering

Transcription

1 JB Neethling HDR Engineering Real World Wastewater Technologies Workshop CBP s Scientific & Technical Advisory Committee (STAC) Richmond, VA May 16, 2012 Copyright 2012 HDR Engineering, Inc. All rights reserved.

2 Outline How reliable does good operating plants perform? What are the costs/features/break t /b points of nutrient removal? What are the benefit/impact of nutrient removal limits?

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4 What is the Best Performance for This Real-World WWTP Dataset? 10 Reliable Value? 10 1 Average Value? Repeated Low value? Next Lowest value? 0.01 Lowest value? Dec-04 Jul-05 Dec-05 Jul-06 Jan-07 Jul-07 Jan-08 Central (all), TP 0.001

5 Define Performance on a Statistical Basis m g/l % % 3.84% % 1% 10% 25% 50% 75% 90% 99% 99.9% Ideal Median Reliable Percent of values less than of equal to indicated value SE TP (all) Neethling et al. (2009) WEF Nutrient 2009, Alexandria, VA.

6 Three TPSs shown TPS-14d (3.84%) Ideal Performance 14-day performance levell TPS-50% Median Performance Average performance TPS-95% Reliable Technology Achievable Performance 5/11/2012 7

7 14-day Values Can Vary Using Rolling Average : mg/l 2007: mg/l 2005: mg/l Dec-04 Jul-05 Dec-05 Jul-06 Jan-07 Jul-07 Jan-08 Central (all), TP Central (all), TP14

8 Nitrogen Process Types Separate Stage Separate processes for nitrification, dentrification MeOH added Filter (denitrification) Combined Conventional, multiple cell BNR (MLE, Bardenpho, step feed, etc. Effluent filter (no MeOH) Multiple Stage Conventional o plus denitrification filter

9 Results: Total Nitrogen by Process 9 Combined Multi SeparateStage Stage 8 7 Total Nitro ogen, mg/l Iron Bridge Piscataway Eastern EWRF Orange Co WSSC Fiesta Village Western Branch River Oaks TMWRF Truckee Meadows Scituate TPS- 14 d TPS- 50% TPS- 95%

10 Phosphorus Process Types 1B = Biological Phosphorus Removal with filter polishing 1C = Single Chemical Phosphorus h Removal with filter polishing 2B = Multistage Biological with Chemical polishing 2C = Multistage Chemical with Chemical polishing

11 Results: Total Phosphorus by Process 0.8 1C 0.7 1B 2B 2C Tota al Phosphoru us, mg/l TPS- 14 d TPS- 50% TPS- 95%

12 Summary Technology performance statistics ti ti allow for rational approach to data analysis and technology assessment Data from well operated nutrient removal plants demonstrated the variability in performance Nitrogen removal plants shows: Best performance 50-60% of median Reliable e performance % of median Phosphorus removal plants shows: Best performance 40-50% of median Reliable performance % of median

13 Permit Period and Reliability Period Basis (days) Sample Permit Percentile Reliable Percentile 5 yr Excee- (%) (%) dance Max Day Max Week Max Month Ann Avg

14 Permit Period and Reliability Period Basis (days) Sample Permit Percentile Reliable Percentile 5 yr Excee- (%) (%) dance Max Day Max Week Max Month Ann Avg Exceed once a year! Acceptable Risk?

15 Reliability at the Permit Limit - TP Plant Process Permit % Exceed #Mo/5yr Exceed #yr/5yr Period Breckenridge 2B % M Pinery 2B % M Rock Creek 2B % M (50%) Cauley Creek 1B % M Gwinnett Co 2B % M CCWRD-AWT 2B % M CCWRD- Central 2B % M Kalispell 1B % M ASA 2C % M DCWASA 1C % A Piscataway 1C % M

16 Reliability at the Permit Limit - TN Plant Process Permit % Exceed #Mo/5yr Exceed #yr/5yr Period TMWRF ( 09) SepSt % M&A Western Branch SepSt % M Fiesta Village Mult % M&A River Oaks SepSt % A Eastern EWRF Orange Co Comb % A Iron Bridge Comb % Scituate SepSt % M WSSC - Parkway Comb % M Piscataway Comb % M

17 What is controlling nutrient removal technologies What are the nutrient species? How well can it be removed? What is the removal efficiencies of individual species? Ideal 80 th Percentile (1 exceedence/5 yr annual limit) 95 th Precentile (3 exceedences/5 yr monthly limit) 5/11/

18 80 th and 95 th Percentile Nitrogen Species in Advanced Treatment 7 6 Concentr ration, mg N/L Part N NH4 NOx DON TN NH4-N = Ammonia; NOx = Nitrite + Nitrate; DON = Dissolved Organic Nitrogen; Part N = Particulate N

19 80 th and 95 th Percentile Phosphorus Species in Advanced Treatment Concentra ation, ug P/L srp snrp Part P TP SRP=Soluble Reactive P; PP=Particulate P SNRP = Soluble Nonreactive P TP = Total P

20 Can you beat the statistics? At a price Additional facilities Increase chemical usage/dose Increased solids management age e cost Improved monitoring Improved source control aka reduce influent variability BUT

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22 Treatment Level Objectives Level BOD (mg/l) TSS (mg/l) TN (mg N/L) TP (mg P/L) <30 < <30 < <30 < <30 <30 2 <0.02

23 Treatment Unit Processes Level Primary Ferm. Act Sludge High Filter MF / Return- Metal Methanol Relative Rate RO Stream Salt (Chem.) Footprint Clar. Treatment (Chem.) 1 1X 2 2X Optional Optional X X 2.5X Denit X Denit. a a RO requires brine management (assumed deep well injection)

24 Tradeoff Between Nutrient Removal and Sustainability Determine sustainability impacts of five levels of treatment for 10 mgd plant Determine if there is a point of p diminishing returns for sustainability with increased treatment

25 What Did We Consider for the Triple Bottom Line? Economic Pillar: Total Project Cost O&M Cost Social Pillar: Discussion in WERF Report Existing metrics (Health) Future metrics (Social) Environmental Pillar: GHGs (Energy Demand, Chem manufacturing/hauling, N 2 O, biosolids hauling) Water Quality Ancillary Benefits of Increased Treatment

26 System Inputs Wastewater Collection Energy Production Chem Mining, Manufacturing, & Hauling GHG GHG GHG GHG Liquid Stream Treatment GHG Biological Solids Treatment (Thicken/Digest/Dewater) Plant Boundary GHG Tertiary Add On Disinfection Cogen GHG GHG GHG GHG GHG Discharge Deep Well Injection (Level 5) Solids Disposal Biosolids Hauling Boundary for this Study

27 GHG Distribution (10 mgd Plant) CO 2 eq mt/yr 18,000 16,000 14,000 12,000 Pumping/ Mixingi Aeration Chemicals N2OEmissions (w/data Range as Bars) Biosolids Hauling and CH4 Emissions Miscellaneous DeepWell Injection 10,000 8,000 Cogeneration 6,000 4,000 2, ,000

28 Incremental GHG per Additional lb N or P Removed dditional lb or P lb) ease per Ad O2 eq lb/n o l GHG Incre moved (CO In ncrementa NP Rem 10, , , Level 1 to 2 Level 2 to 3 Level 3 to 4 Level 4 to 5 Incremental GHG Increase per Change in Treatment Level for N Incremental GHG Increase per Change in Treatment Level for P

29 Incremental GHG per Additional lb N or P Removed ditional lb P lb) ease per Add 2 eq lb/n or al GHG Incre moved (CO2 Incrementa NP Rem 4,000 3,500 3,000 2,500 2,000 1,500 1, , Level 1 to 2 Level 2 to 3 Level 3 to 4 Level 4 to 5 Incremental GHG Increase per Change in Treatment Level for N Incremental GHG Increase per Change in Treatment Level for P

30 Algal Production - GHG Production 25,000 12,500 reatment Level (lb algae/d) Production per T 20,000 15,000 10,000 5,000 10,000 7,500 5,000 2,500 /yr) GHG Emissions s (CO2 eq mt tons Algae 0 Level 1 (No N/P Rem) Level 2 Level 3 Level 4 Level 5 0 Algae Production GHG Emissions Water Environment Research Foundation (WERF) Striking the Balance Between Wastewater Treatment Nutrient Removal and Sustainability November Secondary Treatment (No nutrient removal) 2. Biological Nutrient Removal (BNR) TP 1 mg/l TN 8 mg/l 3. Enhanced Nutrient Removal (ENR) TP mg/l TN 4-8 mg/l 4. Limit of Treatment Technology (LOT) TP <0.1 mg/l TN 3 mg/l 5. Reverse Osmosis (RO) TP <0.02 mg/l TN 2 mg/l

31 What s It Going to Cost You for a 10 mgd Plant? Treatment Level Total Project Costs Operations Cost Total Present Worth ($ Million) i ($/MG) ii ($ Million) iii 1 (No N/P Removal) (8 mg N/L; 1 mg P/L) (4-8 mg N/L; mg P/L) (3 mg N/L N; <0.1 mg P/L) (2 mg N/L N; < mg P/L) 218 1, i ii Iii The total project capital cost are the equipment cost, construction, and soft costs Operations cost = energy and chemical cost. Labor and maintenance costs are excluded The assumed discount rate was 5 percent at an escalation rate of 3.5 percent (capital, energy, non-energy)

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33 Summary and Conclusion - I Even well operating plants shows significant ifi variation in performance The average performance is about 2 times the ideal The reliability of meeting a permit requirement depends on: Averaging period Factor of safety to meet permit Owner risk tolerance Restrictive ti limits it (lower and/or short periods) increases the need for redundant units, multiple barriers to meet permits reliably

34 Summary and Conclusion - II Efficiency i solids separation becomes critical for phosphorus removal Chemical addition provides a tool to improve reliability Chemical usage increase for restrictive limits Ionic species removal drastically increase the treatment costs and impacts The benefit per mass N or P diminish exponentially as the permits become more restrictive

35 JB Neethling HDR Engineering Real World Wastewater Technologies Workshop CBP s Scientific & Technical Advisory Committee (STAC) Richmond, VA May 16, 2012 Copyright 2012 HDR Engineering, Inc. All rights reserved.