Madison Metropolitan Sewerage District. Milwaukee Metropolitan Sewerage District. Matt Seib. Kevin Jankowski

Transcription

1 Advancing Anaerobic Digestion of Wastewater Solids and Food Waste for Energy and Resource Recovery: Science and Solutions - A Framework for the Practice of Co-Digestion Matt Seib Madison Metropolitan Sewerage District Kevin Jankowski Milwaukee Metropolitan Sewerage District

2 Presentation Overview Introduction & Background Co-Digestion Framework Side-Effects & Strategies Waste Receiving Wrap-up & Discussion

3 Introduction & Background

4 NSF/WERF (WRF) Workshop Purpose: Aggregate knowledge from operators, consultants, and academia Determine areas of consensus Identify knowledge gaps to improve viability of future codigestion projects

5 NSF/WERF (WRF) Workshop Group of 40 speakers and participants discussed: existing co-digestion programs practices to improve the success of co-digestion programs recommendations and research needs for the industry

6 Final Report WERF (WRF) Report ENER20W17

7 Co-digestion Framework

8 Framework Pyramid Four Pillars 1. Mission 2. Feedstocks 3. Operations 4. Products

9 Questions for Feedstock Generators What feedstock is available, why is it available, and how much of it is available? Of the feedstock available, does it meet four essential criteria (non-toxic, energy value, low inerts, digestible)? Are there thresholds that would determine any feedstock as unacceptable? What rate structures, testing, and work flow are appropriate based on the feedstock (personnel, leadership, communication/ arrangements with solid waste sector, etc.)?

10 Quality Criteria Sample co-digestion feedstock to determine suitability Looking for beneficial & negative characteristics

11 Biochemical methanogenic potential (BMP)

12 Anaerobic Toxicity Assay (ATA)

13 Questions for WRRF Staff (Operators) What is your baseline capacity and equipment suitability for solids processing, gas processing, and gas use? What are the potential staffing implications? Who does the sampling? What is the effect on permit compliance? Do we need additional sidestream treatment? Do we need feedstock receiving infrastructure? How will we use the energy generated?

14 Digester Gas, cuft/day Examples of Pilot Results 2,750,000 2,500,000 2,250,000 2,000,000 1,750,000 1,500,000 1,250,000 1,000, , , , /19/2018 8/18/2018 9/17/ /17/2018 DG_Calc DG_meas DG_PS DG_WAS DG_HSW DG_NoHSW

15 Permit Compliance? (effluent & biosolids)

16 Permit Compliance? (air permit)

17 Side-Effects & Strategies

18 Co-Digestion Side-effects Additional substrate may have impact in a number of areas including: Odor control Digester foaming and gas quality Sidestream impacts Sludge dewaterability Residuals production

19 General Feedstock Balance Co-digestion Feedstock scod pcod CH4 Digester Gas scod pcod VS AD scod pcod VS Biomass FS scod pcod VS FS Undegraded Feedstock

20 Example Residual Calculation Variable Description Value Units Notes Substrate Sample Analysis Substrate Name Example Q Volume 7,123 gallons truck load COD Chemical Oxygen Demand 27,000 mg/l lab results TS Total solids 21,000 mg/l lab results %VSS Volatile solids fraction 75% % lab results Process Calculations C1 COD to VSS ratio 1.71 lbs COD/lb VSS assumed, can be determined by lab TS Total solids 1,248 lbs calculated VS Volatile solids 936 lbs calculated FS Fixed solids 312 lbs calculated COD Total COD load 1,604 lbs calculated scod soluble COD load 0 lbs calculated pcod particulate COD load 1,604 lbs calculated %REM1 Volatile solids destruction rate 53.00% VS rem /VS 2015 Average, WIMS Var 5027 %REM2 Anaerobic soluble removal rate % scod rem /COD 1/21/14 meeting %REM3 Anaerobic composite removal rate 53.00% COD rem /COD calculated %REM4 Aerobic removal rate 75.00% COD rem /COD assumed, 25% in dewatered biosolids Y1 Anaerobic biomass yield 0.10 lbs VS/lb COD assumed, from Dr.Z Y2 Aerobic biomass yield 0.50 lbs VS/lb COD assumed, from Dr.Z Xv1 Anaerobic biomass produced 85 lbs Assumes no endogenous decay Xv2 Aerobic biomass produced 283 lbs Assumes no endogenous decay Xv Net biomass produced 368 lbs calculated ndvss non-degraded VSS 440 lbs calculated Tse Additional solids to be treated 1,119 lbs calculated 0.56 Tons calculated Unit Values lbs/gallon calculated tons/gallon calculated

21 Waste Receiving

22 Facility Design Concerns Receiving station Unloading system Tanks/equalization Wash down facilities Construction materials Odor control Pumps Heat exchange Explosion resiliency Permit requirements Redundancy Staffing

23 Process Concerns Vehicle traffic Organic loading rates Vector attraction reduction Recuperative thickening Mixing Digester cleaning Reject management

24 Waste Receiving

25 Waste Receiving

26 Waste Receiving

27 Wrap-up & Discussion

28 Discussion