Plug Flow Digester Meadowbrook Dairy Phelan, CA 1200 cow vacuumed drylot 170 kW, separated solids July 2004
Port of Tillamook Bay Regional Dairy Digester 4,000 cow capacity at build out 2,000 cows from 8 dairies contributing today 240 kWh continuous $2,000,000
Operating Requirements: US No time-temperature requirements Maybe you can add food, maybe not HRT – 15 – 25 days Temperature – mesophillic Europe - Canada Pasteurization or time/temp requirement depending on location and added materials and who is making the rules – Germany v Denmark HRT – 12 – 20 days Temperature – depends on HRT
RCM First Accidental Co-digestion 24 years ago cheese whey from Marin French Cheese was added to dairy manure at the Marindale Dairy Digester. Good News! Some whey made some extra gas. The owner then added too much whey and almost killed the digester.
1. Why manure and food waste? Food waste is typically highly biodegradable Society wants degradable wastes managed to minimize public health impact Digesters degrade highly biodegradable materials in a controlled fashion and the effluent doesn’t smell, support flies or vermin. Farm digester manure is a complete substrate Food waste may need nutrients from manure to enhance degradation
2. Why manure and food waste? Farm View Profit Tipping fees Extra Gas and Electricity Production Waste Generator View Reduced disposal cost while meeting society goal of controlled degradation Farm has land to manage the waste.
What digests: Protein - Slaughterhouse waste, fish processing, road kill Vegetable oils Fats, Oils, Grease (maybe not so well) Carbohydrates – starch, sugar, fruit juice,whey and whey products, grains, some grain processing products Most cleaning chemicals
What doesn’t digest: Sticks, leaves Rocks and cement blocks Metal, glass, plastic, rubber gloves Some cleaning or disinfecting chemicals
Bad things to try to digest without testing Petroleum products Chemicals Pesticides and herbicides Toxic anything Drugs
Matlink Dairy, Clymer, NY 900 cows + organic wastes, 130 kW Up to 225,000 ft3/d, solids separated RCM Digesters.com
The learning Check what’s in the truck Big flares can be your friend
RCM Complete Mix Digester Gypsy Hill Farm - Lancaster, PA 4,000 Pigs and Whey Biogas and 120 kW since 1983 Original: Energy Cycle 1983 RCM: redesign, rebuild, increase capacity 2000
The learning: Steady is good
Langerwerf Dairy, Durham, CA 1983, 350 cows, 70 kW, 45 kW without FOG 70 kW plus flare with FOG
The learning: Ditto on too much of a good thing. The consultant really meant what he said.
Patterson Dairy, Auburn, NY, 2005, 1200 cows and whey, 200 kW, big flare, solids
The learning: Ditto on the big flare, gas keeps on coming One mans whey permeate is another mans processed whey concentrate
Van Ommering Dairy, Lakeside, CA. 2005, 600 cows, thick FOG, 130 kW
The learning: Steady feeding keeps the engine running Ditto on the evil nature of utilities – (Sorry I can’t help myself)
Lastly – 28,000 steers and thin stillage, coming 2006
The learning: Learning has no end and Déjà vu happens all over again.
Potential Pitfalls Zoning - Food waste is sometimes ruled an industrial waste. A farm might have to be rezoned for accepting industrial waste. Permitting – Food waste is often regulated as a solid waste. A farm may have to have a solid waste permit and compliance schedule to operate.
Nutrients - The other pitfall: When bringing waste to a farm, are nutrients coming in the waste? Can imported nutrients be used on the farm? Does the nutrient management plan or permit need to be altered? YES!
Advice: Permit a digester for food waste Be honest with the neighbors THERE IS HOPE Enlightened states like New York and Pennsylvania have been reasonable. Enlightenment awaits provinces like Ontario and states like California
The Rules of Digesters Do Feed daily Feed a constant diet Keep the digester warm Don’t Feed too much or too little Over or under heat
The Rules Food Wastes Rule 1. There are no rules. Not all food waste is equal. Waste means waste to the producer. Truckload means what’s in the truck. Quality or quantity? Never on Sunday unless its Sunday.
The Rules of Mixed Wastes A digester that receives food waste should be a digester designed to receive food waste.
The Consequences of Violating the Rules: Death to the digester Dishonor to the operator Loss of waste source.
What RCM Digesters does: 1.Budget Prices 2. Feasibility Study 3. Design and equipment supply 4. Turnkey construction