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Making Waste Productive. Creating Energy from Waste. Creating Energy Inputs from Current Waste Outputs. Organic material ( waste ) can be converted into energy ( methane) through a process called anaerobic digestion
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Creating Energy Inputs from Current Waste Outputs • Organic material (waste) can be converted into energy (methane) through a process called anaerobic digestion • Applications where waste disposal costs $100,000s/year can be turned into energy worth $100,000s/year
Creating Energy Inputs from Current Waste Outputs • Two industries suitable to making energy from waste outputs • Food industry • Cheese/Dairy plants • Snack Food plants • Prepared Food plants • Biofuels industry
Converting Biomass to Energy • The energy value of a waste stream is measured in pounds of chemical oxygen demand (COD) • Every pound of COD digested results in 5.6 cubic feet of methane • An effective anaerobic digester usually converts 95+% of the available COD into methane • Every cubic foot of methane produces around 1,000 BTU’s of energy • Approximately 5,600 BTUs in a pound of COD • A pound of organic solids will contain around a pound of COD • A truck load of solids can contain around 50,000 pounds of COD • Energy potential to power a 1 MW generator on a continuous basis
Segregating Biomass Streams • Process and environmental technologies segregate the insoluble fraction of a biomass stream from the soluble • Isolate the energy potential material within a facility • Clarifiers • Screens • All types of filtration and dissolved air flotation devices • The isolated insoluble high energy potential stream usually ends up on a truck…
Types of Biomass Streams to Consider • Hauled material • Unsalable product • Isolated streams • Wastewater In most applications a significant portion of the energy is contained in a small portion of the waste
Three Most Common Disposal Methods • Land application • Landfill • Animal feed
Paying others to haul and dispose of biomass. . . Is the waste of a valuable asset Stop feeding your cash to cows!
Factors in Renewable Energy Plant Design • Material handling • Solids retention • Good contact • pH control • Temperature control • Nutrients • Gas utilization
Factors that Weigh in an Economic Decision • Avoided disposal cost • Energy value • Green value—Some options have significant federal/state taxes and other credits • Renewable energy credits • Emissions trading credits
Identifying Energy Potential • There is a potential project if… • Gas costs greater than $7 per MM BTU • Electricity costs greater than 7.5¢ per KWh • The plant produces 20,000 lbs. or more COD per day • The plant is situated where there is a Renewable Portfolio Standard (RPS) in place • Significant avoided cost
Identifying Energy Potential • By geographic area, in cooperation with regional facility (power plant, research facility, cooperative) • By individual plant
Identifying Energy Potential • By individual plant: 3-step process • STEP ONE: Data evaluation, using existing plant data • Estimate the effectiveness technology to generate energy in the form of methane gas • STEP TWO: Lab evaluation, using actual samples of plant residuals and organic waste • Determine parameters, limits and potential quantities of methane gas generation • STEP THREE: Demonstration project • Test the design parameters on waste residuals to finalize the optimum factors for a full-scale plant
Evaluating Energy Potential • Demonstration project (pilot) can be an important step to developing design • Material handling, gas storage, waste blending
Demonstration Project: Cheese Plant • Project timeline: 9-29-05 to 5-25-06 • Waste source • Permeate stream • COD concentration averaged 52,000 mg/l • Existing disposal methods • Recovery of whey protein concentrate • Recovery of lactose • Treatment of 350,000 gallons per day of waste in plant-owned treatment plant • Trucked 6,000 gallon of waste from WPC and lactose recovery process
Demonstration Project: Cheese Plant • Demonstration project goals • Replicate a full-scale loading rate • 50 lbs of feed COD/1000 gallons of digester liquid volume • Determine COD Removal Efficiency • Evaluate Gas Quality • Evaluate Material handling needs • Determine optimum factors for a full-scale plant
Demonstration Project: Cheese Plant • Test history • Permeate (whey filtered to remove protein) fed to digester (1-18-06―5-25-06) • Average COD strength of 53,000 mg/l • Ramped up until the target feed rate of 300 lbs COD/day (50 lbs/1000 gallons of digester volume)
Demonstration Project: Cheese Plant • Test history: COD • Operating at design capacity on permeate
Demonstration Project: Cheese Plant • Test history: methane production • Relatively steady • Flow dropped when the gas flow was shut down to clean the gas discharge line of accumulated moisture
Demonstration Project: Cheese Plant • Test history: methane flow per unit of COD removed • Consistently within the projected flow rate of 5.6 cubic feet of methane/lb of COD
Demonstration Project: Cheese Plant • Test history: BOD • Virtually the entire BOD available has been consumed in the digester
Demonstration Project: Cheese Plant • Test history: alkalinity • Stable; most of the alkalinity is retained in the digester, conserving chemical
Demonstration Project: Cheese Plant • Test history: calcium (needed for growth) • Sufficient quantities; supplemental calcium is not required
Demonstration Project: Cheese Plant • Test history: hydrogen sulfide • A contaminant in the gas could cause operational difficulties in high concentrations; data inconclusive
Demonstration Project: Cheese Plant • Test history: solids—TS, VS, TSS, VSS • TSS-No accumulation of total suspended solids
Demonstration Project: Cheese Plant • Test history: Methane and CO2 Production • Bag samples were collected to verify the accuracy of the on-line instruments that measure COD and methane (two manufacturers = 4 instruments)
Demonstration Project: Cheese Plant • Test history ― summary • Conversion of the dairy permeate to energy is straight forward and achievable • Digester operated in a stable fashion • No accumulation of COD in the digester • Converted 98 percent of the COD (>99% of the BOD) to energy • Gas production met the design value of 5.6 cubic feet of methane/lb of COD removed • Energy breakdown • 80% to 100% of gas demand • 1 MW power output plus heat recovery • Status • Demonstration project completed • Final plant design
Demonstration Project: Cheese Plant • Projected ROI—Assumes output of gas to be burned in boilers or fed into a co-generation facility to generate electricity and waste heat • Option A assumes the addition of a co-generation unit and the recovery of heat from that unit • Option B assumes that the biogas is only burned in existing boilers • Both options assume the biogas plant is NewBio’s property and the biogas utilization equipment is the client’s property • Calculations based on 120 months contract term • No “Green Credits” included
Demonstration Project: Cheese Plant • Projected ROI
Demonstration Project: Cheese Plant • Projected ROI
More Information • Contact NewBio • www.newbio.com • mgratz@newbio.com • 952-476-6194