MASS NATURAL FERTILIZER CO., INCFEASIBILITY STUDY OF ANAEROBIC DIGESTION

OF INDUSTRIAL ORGANIC WASTE USING DRY FERMENTATION TECHNOLOGY

JANUARY 2010

PRESENTED TO 10PRESENTED TO 10thth ANNUAL ANNUAL ORGANIC RECYCLING SUMMIT:ORGANIC RECYCLING SUMMIT:

LOCAL ENERGY TAKES ROOTLOCAL ENERGY TAKES ROOTAPRIL 6, 2010APRIL 6, 2010

Bob Spencer and Bill Page, Sr.Bob Spencer and Bill Page, Sr.Mass NaturalMass Natural

Westminster, MAWestminster, MA978-874-0744978-874-0744

FEASIBILITY STUDY OF ANAEROBIC DIGESTION

OF INDUSTRIAL ORGANIC WASTE USING DRY FERMENTATION TECHNOLOGY

JANUARY 2010

Massachusetts Technology

Collaborative

Mass Natural feasibility study funding with Mass Natural feasibility study funding with MTC grant of $40,000, plus $5,000 matchMTC grant of $40,000, plus $5,000 match

MTC now Mass Clean Energy (MCE)MTC now Mass Clean Energy (MCE) Other food waste anaerobic digestion Other food waste anaerobic digestion

feasibility studies sponsored by MCE at feasibility studies sponsored by MCE at Southbridge and the six dairy farms projectSouthbridge and the six dairy farms project

MASS NATURAL PROJECT TEAMMASS NATURAL PROJECT TEAM

Steve Brunner, P.E., The Brundle Group: anaerobic Steve Brunner, P.E., The Brundle Group: anaerobic digestion technology and biogas generation digestion technology and biogas generation assessmentassessment

Richard Gross, P.E.: electrical interconnect Richard Gross, P.E.: electrical interconnect assessmentassessment

Katherine Gegas: Renewable energy creditsKatherine Gegas: Renewable energy credits Bruce Fulford: Regulatory assessmentBruce Fulford: Regulatory assessment Bob Spencer: Project management, waste stream Bob Spencer: Project management, waste stream

survey, and tour of AD facilities in Germanysurvey, and tour of AD facilities in Germany Bill Page: Integration with existing operations at Bill Page: Integration with existing operations at

Mass Natural Mass Natural

MASS NATURAL COMPOSTING MASS NATURAL COMPOSTING FACILITYFACILITY

MASS NATURAL’S OPERATIONMASS NATURAL’S OPERATION Composting pads and a detention basin for runoff

control Composting is accomplished by static pile and turned

windrows Mass Natural recently purchased two in-vessel

composting systems that have expanded the range of materials composted

MN also has a vermicomposting operation to produce vermicompost, as well as red wiggler worms which are offered for sale through the MDEP web site

MATERIALS COMPOSTED SINCE MATERIALS COMPOSTED SINCE 1987: 23 YEARS OF OPERATION1987: 23 YEARS OF OPERATION

Paper mill sludge, or short paper fiberPaper mill sludge, or short paper fiber Chicken and horse manureChicken and horse manure Industrial food waste from processors of cranberries, Industrial food waste from processors of cranberries,

juices, soy, fish, bakeries, FOGjuices, soy, fish, bakeries, FOG Yard waste Yard waste Animal mortalities from former chicken egg farm at Animal mortalities from former chicken egg farm at

Mass Natural and as emergency disposal site for Mass Natural and as emergency disposal site for MDEP MDEP

Numerous TRIALS with commercial food waste Numerous TRIALS with commercial food waste from restaurants and supermarkets (ALWAYS too from restaurants and supermarkets (ALWAYS too much inorganic contaminants!!!)much inorganic contaminants!!!)

EXISTING PERMITS AT MASS EXISTING PERMITS AT MASS NATURALNATURAL

Solid Waste Facility Site Assignment from the Solid Waste Facility Site Assignment from the Town of Westminster Board of HealthTown of Westminster Board of Health

Solid waste composting permits from the Solid waste composting permits from the Massachusetts Department of Environmental Massachusetts Department of Environmental Protection Protection

Agricultural composting registration from the Agricultural composting registration from the Massachusetts Department of Agricultural Massachusetts Department of Agricultural Resources. Resources.

MASS NATURAL COMPOST MASS NATURAL COMPOST PRODUCTSPRODUCTS

““Top Shelf” organic loam, a blend of compost, sand, Top Shelf” organic loam, a blend of compost, sand, loam is distributed by a number of garden centersloam is distributed by a number of garden centers

Compost is distributed by a number of garden centersCompost is distributed by a number of garden centers Vermicompost and red worms for MDEP and garden Vermicompost and red worms for MDEP and garden

centerscenters Products have been used by the landscaping industry Products have been used by the landscaping industry

for new lawns, organic lawn care, and athletic fieldsfor new lawns, organic lawn care, and athletic fields Wetland replication projectsWetland replication projects Landfill cap vegetative coverLandfill cap vegetative cover

HIGH PROFILE COMPOST PROJECTS HIGH PROFILE COMPOST PROJECTS USING MASS NATURAL PRODUCTSUSING MASS NATURAL PRODUCTS

U.S. Army Corps of Engineers wetland reclamationU.S. Army Corps of Engineers wetland reclamation New England Patriots Foxboro Stadium playing field New England Patriots Foxboro Stadium playing field

reconstructionreconstruction MIT’s Steinbrenner Stadium in-field soilMIT’s Steinbrenner Stadium in-field soil Boston Convention & Exposition Center tree plantingsBoston Convention & Exposition Center tree plantings Clay tennis court soil mix at a private resort on Martha’s Clay tennis court soil mix at a private resort on Martha’s

VineyardVineyard Bank stabilization project for the Mass DEP in Worcester, MABank stabilization project for the Mass DEP in Worcester, MA Asian Longhorn Beetle control project in Worcester County: Asian Longhorn Beetle control project in Worcester County:

loam for tree removal area loam for tree removal area

SITE ADVANTAGESSITE ADVANTAGES Existing permits to compost organics;Existing permits to compost organics; Under-utilized, existing buildings within permitted areaUnder-utilized, existing buildings within permitted area Local electrical distribution line is capable of receiving Local electrical distribution line is capable of receiving

considerable current from an on-site engine generator;considerable current from an on-site engine generator; Existing equipment (front-end loaders, rotary drum aerobic Existing equipment (front-end loaders, rotary drum aerobic

compost vessel, agitated bay compost system, deck screens, compost vessel, agitated bay compost system, deck screens, trucks, etc.) and personnel to handle large volumes of organic trucks, etc.) and personnel to handle large volumes of organic material;material;

Many years of experience with, and understanding of, the Many years of experience with, and understanding of, the local organics market;local organics market;

Compost the dry fraction of the digested effluent to add value Compost the dry fraction of the digested effluent to add value to its current product;to its current product;

EXISTING STRUCTURESEXISTING STRUCTURES 6 former chicken houses with concrete pads 65 feet 6 former chicken houses with concrete pads 65 feet

wide by 450 feet long, which may be suitable as a wide by 450 feet long, which may be suitable as a floor for some portion of a new AD facilityfloor for some portion of a new AD facility

A 9,000 sf former egg processing/packaging/storage A 9,000 sf former egg processing/packaging/storage facilityfacility

Electrical building with 3-phase powerElectrical building with 3-phase power Existing padmount distribution transformer that is Existing padmount distribution transformer that is

rated 1,000 kVA, sufficient to export the entire 848 rated 1,000 kVA, sufficient to export the entire 848 kW output from the proposed anaerobic digesterkW output from the proposed anaerobic digester

Water supply wellsWater supply wells OfficeOffice

WET VS DRY TECHNOLOGYWET VS DRY TECHNOLOGYOROR

LOW SOLIDS VS HIGH SOLIDSLOW SOLIDS VS HIGH SOLIDS Project started by looking at both wet and dry Project started by looking at both wet and dry

fermentation systemsfermentation systems Decision to not pursue wet fermentation due to the Decision to not pursue wet fermentation due to the

fact that there is no sewer connection available at fact that there is no sewer connection available at Mass Natural to handle the significant amount of Mass Natural to handle the significant amount of liquid wastewater that would be generated by a wet liquid wastewater that would be generated by a wet fermentation systemfermentation system

Although the liquid wastewater can potentially be Although the liquid wastewater can potentially be land applied, that scenario would have required land applied, that scenario would have required construction of very large holding tanks, and then construction of very large holding tanks, and then contracting for land application, something Mass contracting for land application, something Mass Natural is not prepared to do at this point in time. Natural is not prepared to do at this point in time.

FEEDSTOCKS FOR HIGH FEEDSTOCKS FOR HIGH SOLIDS ANAEROBIC SOLIDS ANAEROBIC

DIGESTION DIGESTION Approximately 52 tons/day Solids Content 62% Volatile Solids 88% of Total Solids Ammonia/Ammonium Concentration: 3,777Mg/l Biogas Generation: 480 m3/hour Methane Content 62% Electrical Output Potential 1,109kW Based on engine-genset electrical efficiency of 36.3%

COMPARISON OF BIOGAS OUTPUT FROM TECHNOLOGY PROVIDERS

Electricity Generation Electricity Generation At full output, the Jenbacher JS3 316 engine genset At full output, the Jenbacher JS3 316 engine genset

has a heat rate of approximately 9,400 Btu/kWh, has a heat rate of approximately 9,400 Btu/kWh, which translates to an electrical efficiency of 36.3%.which translates to an electrical efficiency of 36.3%.

Given typical operations and maintenance schedules, Given typical operations and maintenance schedules, one can expect an engine genset to operate at full one can expect an engine genset to operate at full capacity a maximum of 90% of the hours in a yearcapacity a maximum of 90% of the hours in a year

A dry digestion system will typically use about 7.5% A dry digestion system will typically use about 7.5% of the rated electrical output to run the pumps and of the rated electrical output to run the pumps and controls of the plantcontrols of the plant

Mass Natural can expect to export a maximum of Mass Natural can expect to export a maximum of 6,128,496 kWh/yr.6,128,496 kWh/yr.

Thermal Energy Thermal Energy Mass Natural can benefit from the thermal energy released from the waste heat Mass Natural can benefit from the thermal energy released from the waste heat

from the enginefrom the engine The combined heat that can be captured from the engine jacket is about 1.95 The combined heat that can be captured from the engine jacket is about 1.95

MMBtu/hrMMBtu/hr The amount of heat that can be captured from the exhaust stack is about 1.9 The amount of heat that can be captured from the exhaust stack is about 1.9

MMBtu/hr MMBtu/hr A potential use of the heat is to dry incoming feedstocksA potential use of the heat is to dry incoming feedstocks A rotary drum dryer that would be appropriate at Mass Natural would have a A rotary drum dryer that would be appropriate at Mass Natural would have a

thermal efficacy of about 60%thermal efficacy of about 60% For each 4 MMBtu/hr of heat available, a dryer can evaporate approximately 2,500 For each 4 MMBtu/hr of heat available, a dryer can evaporate approximately 2,500

pounds of water or 300 gallons pounds of water or 300 gallons Therefore, in a typical 8-hour shift, MNF could dry 5 tons of material that has a Therefore, in a typical 8-hour shift, MNF could dry 5 tons of material that has a

solids content of 35% into 4 tons of material that has a solids content of 45%solids content of 35% into 4 tons of material that has a solids content of 45% Mass Natural could utilize the 3.85 MMBtu/hr available from the waste heat of the Mass Natural could utilize the 3.85 MMBtu/hr available from the waste heat of the

engineengine Another option would be to uses the thermal heat for a greenhouse Another option would be to uses the thermal heat for a greenhouse

HIGH SOLIDS BATCH PROCESSINGHIGH SOLIDS BATCH PROCESSING

In a batch process, the digester is completely filled In a batch process, the digester is completely filled with organic matter and closed with a gas- and liquid-with organic matter and closed with a gas- and liquid-tight seal tight seal

The digester remains closed until the end of the The digester remains closed until the end of the desired retention time, typically 14 to 28 daysdesired retention time, typically 14 to 28 days

It is then emptied and filled with new material, often It is then emptied and filled with new material, often a mixture of partially digested material that was just a mixture of partially digested material that was just removed and fresh, undigested materialremoved and fresh, undigested material

The partially digested material acts a seed material to The partially digested material acts a seed material to re-start the digestion process. re-start the digestion process.

LOADING A DRY-BATCH LOADING A DRY-BATCH DIGESTER CELLDIGESTER CELL

GENERATOR AT BEKON FACILITYGENERATOR AT BEKON FACILITY

ADVANTAGES OF HIGH SOLIDS ADVANTAGES OF HIGH SOLIDS AD TECHNOLOGYAD TECHNOLOGY

Because dry material is stackable, the digester can be loaded with a Because dry material is stackable, the digester can be loaded with a front-end loader, which is already at a compost facilityfront-end loader, which is already at a compost facility

When the material is finished digesting, it still has a relatively high When the material is finished digesting, it still has a relatively high solids content. Therefore, the effluent can be composted without having solids content. Therefore, the effluent can be composted without having to remove much liquid from it to remove much liquid from it

Pumping liquid percolate is much easier than pumping slurries, which is Pumping liquid percolate is much easier than pumping slurries, which is the case in most commercial digestion systems. Pumping slurry requires the case in most commercial digestion systems. Pumping slurry requires significant horsepower, and the pipes are prone to cloggingsignificant horsepower, and the pipes are prone to clogging

To reduce the impact of reduced biogas production that occurs when the To reduce the impact of reduced biogas production that occurs when the digester is re-filled, multiple digester “cells” can be employed so that digester is re-filled, multiple digester “cells” can be employed so that several are operating at capacity at any one timeseveral are operating at capacity at any one time

If one digester cell has an upset condition, the percolate from it is If one digester cell has an upset condition, the percolate from it is diluted by the percolate from the other cells, making it easier to re-start a diluted by the percolate from the other cells, making it easier to re-start a “stuck” cell. In an extreme case, the percolate can be completely “stuck” cell. In an extreme case, the percolate can be completely isolated and removed from circulationisolated and removed from circulation

Dry-Batch Digester Installations in Dry-Batch Digester Installations in Europe Europe

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BEKON AND BIOFERMBEKON AND BIOFERM

Mass Natural solicited proposals from two Mass Natural solicited proposals from two German companies, Bekon and Bioferm, that German companies, Bekon and Bioferm, that appear to be market leadersappear to be market leaders

Each has more than a dozen operating Each has more than a dozen operating digesters in Europe and is constructing more digesters in Europe and is constructing more each montheach month

Both technologies share a similar processBoth technologies share a similar process

SIMILAR PROCESSSIMILAR PROCESS Digestible, organic matter is loaded into a long, narrow gas-tight buildingDigestible, organic matter is loaded into a long, narrow gas-tight building Once the building is sealed, it is saturated with percolate that contains Once the building is sealed, it is saturated with percolate that contains

anaerobic micro-organisms from an active digesteranaerobic micro-organisms from an active digester Percolate is periodically drained and re-sprayed into the digester over a Percolate is periodically drained and re-sprayed into the digester over a

period of approximately 28 daysperiod of approximately 28 days Biogas is collected and a combusted in an engine-genset to produce Biogas is collected and a combusted in an engine-genset to produce

electricityelectricity Waste heat from the engine is used to maintain an ideal temperature within Waste heat from the engine is used to maintain an ideal temperature within

the digestersthe digesters After the prescribed retention time, the digester is opened, the organic After the prescribed retention time, the digester is opened, the organic

matter is removed, and some of it (a third to half of it) is mixed with fresh matter is removed, and some of it (a third to half of it) is mixed with fresh organic material and loaded back inside the digesterorganic material and loaded back inside the digester

The digested material is actively composted.The digested material is actively composted.

BEKON AD TECHNOLOGYBEKON AD TECHNOLOGY

BEKON FACILITY BEKON FACILITY

COMPUTER MONITORING OF COMPUTER MONITORING OF EACH DIGESTER BATCHEACH DIGESTER BATCH

BIOFERM FACILITY BIOFERM FACILITY

SUMMARY OF FEASIBILITY STUDYSUMMARY OF FEASIBILITY STUDY

High solids anaerobic process was best suited for the site. High solids anaerobic process was best suited for the site. Mass Natural could digest approximately 52 ton per day of Mass Natural could digest approximately 52 ton per day of

mixed organic mattermixed organic matter Sufficient biogas to power an 848-kW engine genset that Sufficient biogas to power an 848-kW engine genset that

would export over 6.1 MWh a year of renewable electricitywould export over 6.1 MWh a year of renewable electricity The system would cost $5.5M to $8.4MThe system would cost $5.5M to $8.4M Annual operating budget of about $277,000Annual operating budget of about $277,000 Ancillary benefits would include over 3.8 MMBtu/hr of Ancillary benefits would include over 3.8 MMBtu/hr of

thermal energy for on-site usethermal energy for on-site use Over 3,250 greenhouse gas emissions credits for sale.Over 3,250 greenhouse gas emissions credits for sale.

OPERATING COSTSOPERATING COSTS

Operating costs for the anaerobic digester system were estimated by the Brendle report to be approx-imately $130,000 per year assuming 1.5 full-time equivalent employees

Operating costs for the CHP operation are estimated at $137,000 per year

Total operating cost of $277,000 per year

MASS NATURAL PROJECT MASS NATURAL PROJECT REVENUE AND FINANCING FOR REVENUE AND FINANCING FOR

$8.4 MILLION FACILITY$8.4 MILLION FACILITY Project revenue is estimated at approximately $1.9 million in

the first year of full operation. That revenue is based on an average tipping fee of $45/ton of feedstock, and receipt of $0.10/kwh of electricity generated.

Assumptions for project financing were based on 35.5% of total costs financed with solid waste bonds, 23% by investment tax credit, and the balance by equity investment. With this combination of revenue and financing the estimated return on investment, EBITDA (earnings before interest, taxes, depreciation and amortization), divided by pre-debt capital costs, is 13.4%

This yields a payback period of 7.5 years

CONCLUSIONSCONCLUSIONS• Based on laboratory testing of many of these food wastes, it

was determined that 20,000 tons per year of food wastes would generate sufficient quantities of biogas to power a 848 kW generator.

• Two technology vendors with numerous, successfully operating high solids anaerobic digestion technologies currently operating in Germany have technology that is technically feasible for implementation at Mass Natural.

• Sufficient types and quantities of industrial food waste are available within economical hauling distances of Mass Natural’s Westminster, Massachusetts composting facility to supply a 20,000 ton per year high solids anaerobic digestion facility.

• The electrical interconnection from a generator powered by an anaerobic digester is feasible and economical at Mass Natural.

CONCLUSIONSCONCLUSIONS• The Mass Natural site has sufficient space to locate an anaerobic

digestion facility• The current composting operation at Mass Natural would be a

complimentary operation for an anaerobic digestion facility • The regulatory approval process for an anaerobic digestion facility

at Mass Natural was determined to be feasible.• The capital costs for an anaerobic digestion facility at Mass Natural

was determined to be between $5.5 and $8.4 million. For a 20,000 ton per year facility this was determined by Mass Natural to be a marginal investment.

• Mass Natural would like to conduct further evaluation to identify less costly high solids dry fermentation technologies.