MIXED LIQUOR FERMENTATION FOR CARBON AUGMENTATION BREAKING FREE FROM AN UNFAVORABLE INFLUENT CARBON BALANCE

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1 MIXED LIQUR FERMENTATIN FR CARBN AUGMENTATIN BREAKING FREE FRM AN UNFAVRABLE INFLUENT CARBN BALANCE Matt Bond, Associate Vice President Patrick Dunlap, Wastewater Process Specialist

2 UNDERSTANDING BI-P TRADITINAL FLW DIAGRAMS FR BILGICAL NUTRIENT REMVAL (BNR) Anaerobic Anoxic Aerobic 2

3 UNDERSTANDING BI-P ANAERBIC CNDITINS PHSPHRUS RELEASE AND PLY-P DEPLETIN Poly-P Poly-P P P Poly-P Phosphate Using Energy PHB PHB PHB VFA Magnesium Adenosine Tri-Phosphate Bio-battery for energy storage P Volatile Fatty Acids P P N N H H ATP H 2 N N N 3

4 PHB Poly-P Electron microscope Poly-P stains black, PHB stains white Poly-P November 16-18, 2010

5 UNDERSTANDING BI-P AERBIC CNDITINS PHSPHATE UPTAKE AND PLY-P PRDUCTIN Poly-P Poly-P Poly-P P Making Energy Phosphate P Magnesium P Bio-battery is recharging P N H H ATP H 2 N N N N PHB PHB PHB PHB Aeration Basin 5

6 B&V - 6 May 11-14, 2010 Poly-phosphate stored in the aerobic zone. Phosphorus is removed with the WAS. Poly-P January 21, 2011, 2010

7 Why is Bio-P Removal Perceived to be Inconsistent? We have over 20 years of Bio-P history and many plants perform exceptionally well However some plants with CD:P > 40 ratio don t remove P to below permit or will in the summer but not in the winter WHY??? Biological phosphorus removal is notoriously unreliable Recent IWA Conference Paper Biological phosphorus removal is something you design for, hope for, then add chemicals if is doesn t work Poul Harremoes 1998 NT ALL INFLUENT CD IS EQUAL: INFLUENT QUALITY IS THE KEY T SUCCESSFUL BI-P PERFRMANCE 7

8 THE IMPRTANCE F INFLUENT SAMPLING BNR will not work. Chemicals or a fermenter required. BNR will work. Soluble & Degradable Soluble & Non-biodegradable Soluble & Degradable Particulate & Degradable Particulate & Non-biodegradable Particulate & Degradable Soluble & Non-biodegradable Particulate & Non-biodegradable Wastewater Chemical xygen Demand Methods for Wastewater Characterization in Activated Sludge Modeling (Melcer et al., 2003) 8

9 rbcd/p ratio THE IMPRTANCE F INFLUENT SAMPLING 25.0 VIP McDowell Creek 20.0 Durham Eagle s Point Reedy Creek Below the curve plants struggle with BPR At or above curve plants achieve good BPR Fraction of rbcd that is VFA 9

10 WHAT FACTRS AFFECT INFLUENT SLUBLE CD AND VFA? R. WHY WULD DR CMPLAINTS FRM THE CLLECTIN SYSTEM EVER BE A GD THING? Fermentation produces H 2 S (odor) and also influent rbcd and VFA Collection System factors promoting VFA formation High Water Temperature Long Travel Time Flat (Solids Accumulation) Forcemains (No Headspace) 10

11 CASE IN PINT: HENDERSN NV Plant was consistently achieving permit limit and then it wasn t Plant had entirely lost biological phosphorus removal Sampling revealed VFA was not longer present in influent What happened? A casino had began to discharge nitrates for odor control downstream of their discharge. Fixed odor problems but also removed the VFA 11

12 PTENTIAL SCENARIS FR VFA Plenty of VFA in influent wastewater means VFA augmentation not needed fermentation has already occurred in the sewer Plenty of rbcd (not much VFA) in influent means that fermentation occurs in the anaerobic zone Not enough VFA or rbcd means rbcd and VFA must be made elsewhere on site or added as supplemental carbon augmentation needed Direct rbcd Supplementation Primary Fermentation RAS Fermentation Mixed Liquor Fermentation 12

13 FERMENTATIN PTINS 1. Primary Sludge 2. Return Activated Sludge 3. Mixed Liquor Fermentation Substrate Hydrolysis rbcd Fermentation VFAs Methane Formation Methane Influent 1 3 Anaerobic Anoxic 2 Aerobic Primary Sludge WAS 13

14 rbcd/p ratio 25.0 PRIMARY FERMENTATIN VIP McDowell Creek Durham Reedy Creek Raw Influent Eagle s Point PST ptional Recycle Below the curve plants struggle with BPR At or above curve plants achieve good BPR Anaerobic 0.0 To Digesters Fraction of rbcd that is VFA Highest Yield of VFA for amount of VSS destroyed Relatively complex operation Additional facilities needed Removes a potential for energy generation dors control will likely be needed 14

15 RAS FERMENTATIN Secondary Influent Anaerobic Anoxic Aerobic VFA RAS Fermenter WAS RAS Fermenter receives 4-7 % or RAS Flow for Hours HRT (Vollertsen, 2006) Much more common in Northern Europe. For example, this is used at more than 30 plants in Denmark. Lower VFA yield per VSS destruction than with primary sludge (Yuan, 2010) 15

16 MIXED LIQUR FERMENTATIN Fermenter Fermenter Mixed Liquor Recycle from Production Unmixed Anaerobic of rbcd for solids Zone accumulation rbcd and VFA returned Particulate SRT > 2 days ~10% BD of hydrolyzes Influent Flow to Anaerobic or Anoxic Hs Mixed lyses/hydrolyze for Particulate several minutes BD per day for wasting Zone BioP bacteria accumulate incorporated some into VFA MLSS Hs Present Sidestream In-Line Mixed Mixed Liquor Liquor Fermentation Fermenter Mixed Liquor Fermenter Secondary Influent Anaerobic Unmixed Anaerobic Anoxic Aerobic WAS 16

17 ADVANTAGES F MIXED LIQUR FERMENTATIN Primary Sludge Fermentation Need Primaries More Complex peration Higher Capital Investment Higher dor RAS Low Yield Mixed Liquor Fermentation Inline Simple operation Combination of sources Increased Yield 17

18 HENDERSN NV Turning off mixer is the same as bypassing flow around the anaerobic cell Ferments about 10-15% of the MLSS 18

19 SURFACE APPEARANCE F HENDERSN PLANT During mixing Some hours after mixer off 19

20 LATHE KANSAS HAS A FRESH INFLUENT WITH LW VFA AND LW rbcd Influent has enough BD to support BNR but a low soluble BD fraction Special sampling and modeling demonstrated that system is deficient in soluble carbon 20

21 UNIQUE FERMENTER FLW PATH Pump into Fermenter (from end of AN zone) Intermittent mixing verflow out of Fermenter To AN Zone r AX Zone 21

22 Fermenter Modified feed to distribute evenly along the bottom

23 Fermenter (opposite end)

24 FERMENTER STARTUP Weekly solids inventory Mixers control wasting and solids retention time Mix 3 min/day 2 5 days SRT 24

25 rbcd/p ratio LATHE WITH MIXED LIQUR FERMENTATIN 25.0 VIP McDowell Creek 20.0 Durham lathe Reedy Creek At or above curve plants achieve good BPR 5.0 Below the curve plants struggle with BPR Fraction of rbcd that is VFA 25

26 LATHE EFFLUENT SINCE STARTUP No Chemical Addition Permit limits go into effect July 1,

27 TEN MILE CREEK MIXED LIQUR FERMENTATIN DEMNSTRATIN Basin 5 Unused Basin 4 Unused Secondary Clarifier Ae Basin 3 Demo Ae An Primary Clarifier Phase 12 3 : Baseline Fermentation Dedicated Phoredox Mixed in Sludge Liquor Blanket Fermenter To Gravity Thickener (Not Pictured) 27

28 MDELING MIXED LIQUR FERMENTATIN Working on comparing VFA and rbcd yield from VSS destruction from projects to Model predictions Main SRT, MLF SRT, Influent, Primary Removal All impact VFA yeild Consulting with Envirosim (BioWin) on this 28

29 ACKNWLEDGEMENTS City of Henderson NV City of lathe Kansas Trinity River Authority 29

30 QUESTINS? KELLER FERMENT ATIN: UNLEASHI NG THE PWER AND MAKING IT WRK

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