Making Waste Productive

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 plantsSnack Food plantsPrepared 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

facilityClarifiersScreensAll 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

Conversion of organic materialRaw input material:

Fats, Oils, proteins, starches, carbohydrates, sugars

Digester

Acetogenic bacteria break complex food molecules down to

produce Carbon dioxide and Acetic Acid

Methanogenic bacteria break acetic acid down

to produce Methane

Acetic Acid

Carbon Dioxide Methane: 5.6 ft3/ lb COD

Discharge:

>95% COD Removal

99% BOD Removal

Biomass accumulation: ~1% of Aerobic rate

• Air is not used so process proceeds at a much lower energy input than Aerobic treatment

pH Adjustment

Temperature Control

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 projectTest 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 plantTrucked 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 fashionNo accumulation of COD in the digesterConverted 98 percent of the COD (>99% of the BOD) to energyGas 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

● [email protected]

● 952-476-6194