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This presentation has been provided as part ofEPA’s Sustainable Food Management WebinarSeries. This document does not constitute EPApolicy. Mention of trade names or commercialproducts does not constitute endorsement orrecommendation of use. Links to non-EPAwebsites do not imply any official EPAendorsement of or a responsibility for theopinions, ideas, data, or products presented atthose locations or guarantee the validity of theinformation provided. Links to non-EPA serversare provided solely as a pointer to informationthat might be useful to EPA staff and public.

Biodigester Enterprises atUW Oshkosh

Biodigester Enterprises atUW Oshkosh

Greg Kleinheinz, R.S., Ph.D.University of Wisconsin Oshkosh

920-424-3302kleinhei@uwosh.edu

University of Wisconsin SystemUniversity of Wisconsin System

THETHE BIOFERMBIOFERM™ PLANT AT THE UWO CAMPUS™ PLANT AT THE UWO CAMPUS

The First Commercial Scale DryFermentation System in the Nation!

UW Oshkosh Biodigester IIRenewable Energy Facility

Small Farm Applications

Supply of BiomassSupply of Biomass

Weiland, 2010 8

0

1000

2000

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7000

8000

1 2 3 4 5 6 7 8 9 10

Hypothetical Feedstock Source Profile

Tons/Year

Municipal Food

IndustrialFoodProcessorWaste

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1000

2000

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7000

8000

1 2 3 4 5 6 7 8 9 10

Year (Note: Facility lifetime is >20 yrs)

IndustrialFoodProcessorWaste

Farm Waste

Municipal Yard Waste UWO

Community Involvement

2 Main Substrates used at UW2 Main Substrates used at UW--OO

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Ultimate Goal for Dry DigestersUltimate Goal for Dry Digesters

Waste to EnergyOrganic Waste + Microorgansism

=Biogas + DigestateEnergy

Waste to EnergyOrganic Waste + Microorgansism

=Biogas + DigestateEnergy

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Dry Fermentation OverviewDry Fermentation Overview

Uses moisture from organic input to facilitate AD,additional required liquid is the percolate housingbacteria

Microbes within percolate are sprayed to inoculate theorganic material and stimulate decomposition

Generated biogas is collected above the fermentors androuted to utilization room (CHP)

Residual organic material up to level 4 compost◦ Can be used as fertilizer for soil enrichment or further composting

Percolate is recycled and used again in a closed loopsystem eliminating risk of groundwater contamination

Uses moisture from organic input to facilitate AD,additional required liquid is the percolate housingbacteria

Microbes within percolate are sprayed to inoculate theorganic material and stimulate decomposition

Generated biogas is collected above the fermentors androuted to utilization room (CHP)

Residual organic material up to level 4 compost◦ Can be used as fertilizer for soil enrichment or further composting

Percolate is recycled and used again in a closed loopsystem eliminating risk of groundwater contamination

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Dry Fermentation ProcessDry Fermentation Process

Batch Approach◦ At 28 days – portion of digested material is extracted

and mixed with new material and mixed◦ Mixed batch reloaded into chamber for new cycle Composition = 50% fresh

= 50% partially digested material

◦ Why mix? Neutralization of pH of the fresh inputs and inoculates fresh

material

◦ In floor heating system maintains temperature at38°C

Batch Approach◦ At 28 days – portion of digested material is extracted

and mixed with new material and mixed◦ Mixed batch reloaded into chamber for new cycle Composition = 50% fresh

= 50% partially digested material

◦ Why mix? Neutralization of pH of the fresh inputs and inoculates fresh

material

◦ In floor heating system maintains temperature at38°C

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Dry Fermentation

Dry Fermentation eliminateswaste water

Dry Fermentation does notrequire pre-treatment of organicmaterial because it is stationary

Dry Fermentation has reducedenergy load due to reducedelectrical/mechanical needs andmesophilic working range

Biomass input remains stationaryin dry fermentation whilebacteria flows through thebiomass, resulting in significantcost and energy savings

Wet Fermentation

Wet Fermentationincreases waste water

Requires pre-treatment oforganic material due topulping

Needs more energybecause of mechanicalinputs for stirring of sludge

Requires continual biomassinput increasing cost andenergy

Advantages of Dry FermentationAdvantages of Dry Fermentation

Dry Fermentation eliminateswaste water

Dry Fermentation does notrequire pre-treatment of organicmaterial because it is stationary

Dry Fermentation has reducedenergy load due to reducedelectrical/mechanical needs andmesophilic working range

Biomass input remains stationaryin dry fermentation whilebacteria flows through thebiomass, resulting in significantcost and energy savings

Wet Fermentationincreases waste water

Requires pre-treatment oforganic material due topulping

Needs more energybecause of mechanicalinputs for stirring of sludge

Requires continual biomassinput increasing cost andenergy

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The BIOFerm™ plant at the UWO campusThe BIOFerm™ plant at the UWO campus

A 4-fermenter plant with additional biomass storagecapacity.

Total Building Footprint: 19,000 ft2Fermenter: 70 ft x 23 ft x 16.7 ftTotal Fermenter Volume: 26,887 ft3Storage Area: 2,000 ft2Mixing Area: 7,800 ft2Installed Electric Capacity: 350 kW

Storage of BiomassStorage of Biomass

30 m

Fermentation Chambers

NewBiomass

28 day cycle Partially digested material is extracted and mixed in

1:1 ratio with new material

Mixing Platform7m

4.1 m

Old Biomass

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Photo taken by KevinCrawford Dec, 2009 18

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Loading of Biomass

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21

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GAS STORAGE GAS

GAS

Electricity and Heat are generated…

PERCO-LATE

GENERATOR

GAS

BIOMASSHEAT

ELECTRICITY

HEAT HEAT

Solid “digestate” aerobic composter site(can be custom batched – e.g. organic)

UW Oshkosh Renewable Energy Facility

UWOCSC

Oshkosh WastewaterTreatment Plant

Fox ValleyTechnical College

Oshkosh SeniorCenter

WPS

HEAT

CHP Generator: 370 kWAnnual Electric: 3,000 MWh (ca. 10% of UWO)Annual Heat: 3,400 MWh (ca. 10% of UWO)

City of OshkoshYard Waste Site

UWO Campus

HEAT

Dairy Farms (bedding)

Food Processing Plants Food Waste Collectors

CommercialComposter

Laboratory TestingLaboratory TestingLaboratory TestingLaboratory Testing

Need for Laboratory andNeed for Laboratory andPilot TestingPilot Testing

•As consumer of feedstockone needs to know thecomposition and biogaspotential of each feedstock(and digestate).•Dry fermentation and wetare different – lack ofinformation.•Must also know thelimitations of eachfeedstock and microbialbiochemistry can often belimited by micronutrients.

•As consumer of feedstockone needs to know thecomposition and biogaspotential of each feedstock(and digestate).•Dry fermentation and wetare different – lack ofinformation.•Must also know thelimitations of eachfeedstock and microbialbiochemistry can often belimited by micronutrients.

Need for Laboratory and Pilot TestingNeed for Laboratory and Pilot Testing•Ability to blend feedstock toachieve optimal performance iskey to maximizing biogaspotential.•Maximizing biogas potential iskey to rapid payback of facilities.•Odor mitigation studies

•Ability to blend feedstock toachieve optimal performance iskey to maximizing biogaspotential.•Maximizing biogas potential iskey to rapid payback of facilities.•Odor mitigation studies

Need for Laboratory, Pilot, and FullNeed for Laboratory, Pilot, and Full--Scale TestingScale Testing•UW Oshkosh has noticed asignificant difference in biogaspotential from a wide-array offeedstocks that are locally available.•Ability to blend feedstock•Ability to build upon for simple labdata and test in pilot-scale units todemonstrate efficacy.•Ability to place feedstock in full-scale application for proof of conceptin industrial-scale unit.•Cradle to grave approach to simpletesting through proof of concepts.•Development of additives andmicrobial augmentations tomaximize biogas generation incustomized feedstock blends.

•UW Oshkosh has noticed asignificant difference in biogaspotential from a wide-array offeedstocks that are locally available.•Ability to blend feedstock•Ability to build upon for simple labdata and test in pilot-scale units todemonstrate efficacy.•Ability to place feedstock in full-scale application for proof of conceptin industrial-scale unit.•Cradle to grave approach to simpletesting through proof of concepts.•Development of additives andmicrobial augmentations tomaximize biogas generation incustomized feedstock blends.

Questions!

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