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 ►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!

How the Anaerobic Process Works to Create Energy

Creating Energy Using the Anaerobic Process

Factors in Renewable Energy Plant Design ►Material handling ►Solids retention ►Good contact ►pH control ►Temperature control ►Nutrients ►Gas utilization

The Economics of Making Waste Productive

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 and Evaluating Energy Potential

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: to ►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 ( ― ) 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 CO 2 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

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