Effective Use of Carbon in Nutrient Removal Systems

Transcription

1 Effective Use of Carbon in Nutrient Removal Systems Anthony D. Giovannone, PE Gary Sanitary District Case Study November 13 th, 2018

2 Overview PAO Metabolism (& the Future of Nutrient Removal) Operational Considerations for Nutrient Removal Carbon Management Operational Strategies for Consistent Nutrient Removal Phosphorus Removal Case Study: Gary Sanitary District 2

3 3 PAO Metabolism

4 Conventional PAO Metabolism Can you replace O 2 with NO x? (S2EBPR) VFA s stored as PHA (P-released) Adapted from Lin et. al Oxygen as Electron Acceptor (P-Stored) 4

5 5 Operational Considerations for Nutrient Removal: Use Your Carbon Efficiently

6 Carbon Management Carbon Required for EBPR Typically between COD:P COD:O 2 = CARBON BUCKET PAOs dpaos COD:NO 3 -N = The observed COD:N or COD:P is an effective way to understand the efficiency of your nutrient removal process OHOs GAOs OHOs 6

7 Operational Strategies for Consistent Nutrient Removal Minimize DO High Flow Management (Step-Feed) DO Control: Ammonia Based Aeration Control (SND) NH 3 -N Minimize NOx Selector- Fermenter Zones (S2EBPR) Real-Time Monitoring (Sensors) Hydraulic/Surface Wasting

8 8 Case Study- Gary Sanitary District

9 Gary Sanitary District (GSD) WWTP Parameter Design (2001) Current ( ) ADF (MGD) MDF (MGD) Tertiary Sand Filters (Currently in Start- Up/Commissioning) A/O Process with Anaerobic Selectors Fermentation in Gravity Thickening Tanks Ferrous Chloride Addition to Side Stream Ahead of Primary Clarifiers 9 Passive Step-Feed for High Flow Management

10 GSD WWTP Phosphorus Limit Gary Sanitary Disctrict Phosphorus Limit Per the NPDES permit, the total phosphorus limit is dependent on the influent phosphorus concentration. For Phosphorus above 5 mg/l the effluent limit is 1 mg/l. When the influent phosphorus is below 5 mg/l the limit is based on percent removal. (Note: Permit is based on a monthly average) Influent Concentration (mg/l) % Removal Required 4 80% 3 and < 4 75% 2 and < 3 70% 1 and < 2 65% < 1 60% Condition ( ) Average Month Minimum Month Maximum Month Influent TP (mg/l) Permit TP (mg/l)

11 Creating Anaerobic Conditions Low Density Diffuser Grid: 1/3 of 1 st pass in each bioreactor train Operator adjustable valve to adequately mix zone & maintain low DO 2 MG anaerobic (10% total volume) Average HRT: 60 min Originally designed as anoxic selector zone 11

12 Stabilizing SRT SRT (Days) Experienced GBT Problems SRT: June 2017 through June 2018 SRT 10 per. Mov. Avg. (SRT) 0 Jun-17 Jul-17 Sep-17 Oct-17 Dec-17 Feb-18 Mar-18 May-18 12

13 Optimal Influent Carbon BOD 60,000 50,000 40,000 30,000 20,000 10,000 Average Annual Primary Effluent Loads 16,000 14,000 12,000 10,000 8,000 6,000 4,000 2,000 TKN BOD lb/d TKN lb/d TP lb/d BOD:P BOD:N

14 Optimal Influent Carbon 2018 BOD:P Influent Primary Effluent Average BOD:P cbod:p June 2017 through June 2018 Eliminated ferrous addition to side stream 0 Jun-17 Jul-17 Sep-17 Oct-17 Dec-17 Feb-18 Mar-18 May-18 Primary Effluent BOD:P Influent cbod:p 14

15 Eliminating Chemical Ferrous Usage (gpd) Ferrous Chloride Usage and Final Effluent TP June 2017 through June Jun-17 Jul-17 Sep-17 Oct-17 Dec-17 Feb-18 Mar-18 May-18 Ferrous Average Final Effluent TP (2018) Final Effluent TP 0.12 mg/l Final Effluent TP (mg/l) 15

16 TP Results TP Concentration (mg/l) TP (mg/l) Influent Primary Effluent Influent, Primary Effluent and Secondary Effluent TP Secondary Effluent Average Jun-17 Jul-17 Sep-17 Oct-17 Dec-17 Feb-18 Mar-18 May-18 Influent TP Primary Effluent TP Secondary Effluent TP 16

17 Phosphorus Profiles Sample Number Ortho-P (mg/l) Profiles confirmed PAO activity (release and uptake) Some sampling Events showed decrease in Ortho-P ahead of release Potential dpao activity (needs further laboratory confirmation) 17

18 Cost Savings Month Usage (gal) Cost Usage (gal) Cost Savings January 13,434 $ 2, $ 175 $ 2,351 February 16,483 $ 3,099 0 $ - $ 3,099 March 19,643 $ 3,693 0 $ - $ 3,693 April 18,770 $ 3,529 0 $ - $ 3,529 May 19,039 $ 3,579 0 $ - $ 3,579 June 16,581 $ 3,117 0 $ - $ 3,117 July 13,912 $ 2,615 0 $ - $ 2,615 August 13,296 $ 2,500 0 $ - $ 2,500 September 18,469 $ 3,472 0 $ - $ 3,472 October 19,124 $ 3,595 0 $ - $ 3,595 November 19,193 $ 3,608 0 $ - $ 3,608 December 9,163 $ 1,723 0 $ - $ 1,723 Average 16,426 3, $ 15 3,073 Total 197,107 $ 37, $ 175 $ 36,881 No chemical use is expected for the remainder of 2018 System will stay active for use as needed GSD competitively bid Ferrous to maintain a fixed priced contract Anticipated 18

19 Acknowledgements: Daniel Vicari (GSD) Rhonda Anderson(GSD) Michele Gray (GSD) Mandeera Wagle (CDM Smith) Chris Martel (CDM Smith) Contact:

20 SC (non VFA) Fermenters VFA s PAOs SC (non VFA) PAO/DPAO (Specialized) Internalized Product SC (non VFA) Electron Acceptor (DO, NO 3 ) OHOs VFA s PAOs 20

21 21

22 Rethinking PAO Metabolic Pathways Adapted from Winkler et. al

23 A Global Perspective on Phosphorus Current proven reserves will last between 100 to 300 hundred years Morocco will obtain a much greater share of worldwide production, from around 15% in 2010 to around 80% by 2100, which implies more control over market prices (Cooper et al. 2011) THERE IS NO SUBSTITUTE FOR PHOSPHORUS IN AGRICULTURE