ORGANICS RECOVERY ALTERNATIVES

Transcription

1 ORGANICS RECOVERY ALTERNATIVES Strive for Sustainability Conference May 18-21, 2014 George Bevington, Gerhardt LLC

2 What does SSO mean? Wastewater Acronym: Bad phrase Environment Negative SSO = Sanitary Sewer Overflow Solid Waste Acronym: Good phrase Environment Positive SSO = Source Separated Organics

3 SSO Mandate? Source Separation of Organic (SSO) waste already mandated at adjacent states Institutions first, household level eventually? New York State legislation in discussion, probably just a matter of time before requiring SSO New York City: legislation adopted

4 Ultimate Flow Chart? Solid Waste SSO Processing Anaerobic Digester (not final destination) Reduce Reuse Recycle Disposal Permitted Compost Facility

5 If SSO mandated, large quantity of organics available for digestion, capacity needs to be built

6 Where will AD capacity be built? SSO will require the need for anaerobic digestion facilities to be constructed Existing capacity not sufficient to process extra loadings Focus of this presentation is site options/advantages/disadvantages

7 Site Options: At a WWTF At a Landfill Anaerobic Digestion Location At a Farm At a Compost Facility

8 Organic Decomposition Has occurred naturally for thousands of years Organic material + bacteria = Simple compounds Inorganic material will not break down Given time, organics will breakdown without our help but we want to do it faster We want to breakdown organics in a controlled manner to harness the byproducts of digestion

9 Digestion Everywhere 1. Human Digestion 15 hours 2. Anaerobic Digestion 15 days 3. Landfill Digestion 15 Years Unfortunately, energy recovery occurs only in both 2 & 3!

10 Simplified Anaerobic Digestion Organic Matter Acid Forming Bacteria Organic Acids Organic Acids Methane Forming Bacteria Methane (CH4) + CO2 Organic Acids

11 Anaerobic Digestion Basics Food: Liquid/Sludge continuous feed Large Tank/vessel 2 to 5% solids Anaerobic (NO oxygen) Neutral ph Stage One: Bacteria convert to organic acid Stage Two: Methanogens Keep at degrees F 15 day detention time Biogas ~60% methane Sludge Stabilized and Reduced 33%

12 Simplified Digester Gas to Storage or Compressor Gas Outlet Sludge Inlet Mixing Sludge Outlet

13 Disadvantages of Anaerobic Digestion Capital investment Requires steady stream of properly prepared organics Produces a poor quality side-stream (Digestate) that need further treatment Methane-forming bacteria grow slowly

14 Digester Food Dairy whey Salad dressing Fats, oils, and grease Manure Outdated beer and soda Pulverized food waste (SSO) Small particles, no contamination, no grit

15 Co-Digesting SSO at a Wastewater Treatment Plant Wastewater Sludges Biogas Anaerobic Digester Source Separated Organics

16 Vast Network of Wastewater Digester Locations (NYSERDA) NYS WWTPs w/existing Anaerobic Digestion Facilities (145)

17 Wastewater Components Co-Digestion System Energy Recovery Digester Gas Flare Gas Holder

18 High Strength Waste/SSO Receiving Station:

19 High Strength Waste EQ Equalization tank to store high strength waste slurry Accept waste during weekdays usually day shift Allows for pumping of organics to the digester 24/7 at slow constant rate

20 Biogas Generators Produce steady supply of biogas Generation of electricity key to reduce O&M costs and to pay for capital improvements 90 to 100% energy production possible with co-digestion

21 High Strength/SSO Tip Fees: SSO wastes to digesters: charge tip fees Important revenue stream, stabilized wastewater rates $815,275 $892,283 $524,040 $555,262 $360,782 $374,917 $403,567 $394,446 $202,662 $54,159 $37,785 $98,809 $131,

22 Anaerobic Co-Digestion at the Farm 5,600 dairy farms in NYS 625,000 dairy cows 12.4 billion lbs. of milk produced (3 rd largest state) 23 Farm digesters in NYS, 3 in planning and implementation (source Cornell University)

23 NYS Large Farms ~150: Number Mature Dairy Cattle Total Number of Farms Between 700 and Between 1000 and Between 1500 and Over Source: DEC 2012 Compliance Reports

24 Co-Digesting SSO at the Farm Source Separated Organics Biogas Manure Farm Anaerobic Digester Bedding Material Liquid to Crops

25 Manure and SSO to Electricity is NOT a quick way to make money Electricity revenue generated needed to pay for infrastructure and maintain equipment Manure pit: environmental issue at CAFO farms, reduced organic load after digestion Farmer concern: disease from outside users Farmers Get Rich? Farmer s Concerns?

26 Typical Farm Digester: Barn manure plus milking operation waste water to receiving pit Add outside SSO waste at receiving pit Typically low tech 98 degree F digester, fully or partially mixed Farmer manages liquid in and out, digester effluent better for CAFO operation

27 Farm Digestate Solids: Cow Bedding

28 Farm Power Generation Biogas 55 to 60% methane Suitable renewable fuel source for electrical generator Interconnection to electrical grid: very easy to extremely difficult Net metering allowed

29 Digesting SSO at a Landfill Source Separated Organics Landfill Anaerobic Digester Biogas

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31 Advantages of SSO at the Landfill: SSO collection can be done by existing waste haulers Existing Solid Waste Systems have infrastructure in place for garbage, recyclables, and other waste streams. Accounts established, weight scale and billing systems in place Substantial investment already made in biogas recovery, biogas treatment, and electric generation at most landfills.

32 Electrical Interconnect Existing landfill gas to energy systems export power to the grid Grid interconnection is costly and requires long time frame for approval

33 Digesting SSO at a Compost Facility Source Separated Organics Biogas Digestate Solids to Compost Yard Waste Compost Facility Anaerobic Digester

34 What Alternative is Best? Depends Wastewater Farm Landfill Compost Electricity Generation Interconnection with grid difficult Net metering advantage Most have already connected Interconnection with Grid difficult Digester liquid disposal Send to head of plant Send to farm pond/crops Difficult if far from POTW Difficult if far from POTW Digester solids disposal Use existing solids handling systems Use as bedding material in barn Send to compost? Send to compost Capital Cost High Least cost High High Other Years experience with AD, vast network of WWTP Full recycle of food to land Weight scale and haulers Maybe good to blend with compost

35 Score 6,000 to 200: AD in NYS 145 AD at wastewater 23 AD at farms?? Industrial AD Total: ~200+ AD in Germany ~6,000 digesters constructed and operational

36 SSO: need food pulp only Contaminants like bones, packaging, dishes, cutlery, light & hard plastic etc. REMOVE!

37 Private Sector Comment: At 12 cents/kwh, multiple investors and technology providers will be interested in constructing several digesters throughout New York State Therefore, need legislation to help make economics work Federation Backing????

38 Questions?