2008 ASABE Annual International MeetingRhode Island Convention Center
Providence, Rhode Island June 29 – July 2, 2008
On-Farm Anaerobic Digestion Biogas Production
in Pennsylvania – 30 Years
Deborah A. Topper Research Technician Patrick A. Topper Sr. Research Technologist
Robert E. Graves Professor
The Pennsylvania State University
Pennsylvania has the distinction:
Four of the oldest continuously operating farm-based anaerobic digesters
30 years – Mason Dixon Farm (Gettysburg, PA)
1984 First poultry digester up and running (24 years)
Combined operating experience of these four digesters is 99 years
Sixteen (16) known operating farm-based anaerobic digesters (AD) in Pennsylvania
11 Dairy - 8695
3 Swine - 6600
1 Poultry (layers) – 72,000
1000 Beef + 120,000 Poultry
1 industrial AD under construction @ a Swiss Cheese Plant
2 in Design phase 7 in Planning phase
1 Beef & Poultry –
What is an anaerobic digester?
Air tight, oxygen free container, usually concrete
Continues the digestion process of organic materials such as animal manure and food wastes
Heated to maintain optimum temperature 99oF or 135oF
Biogas is produced (60% methane & 40% carbon dioxide)
Biogas can be used to run an engine generator set creating electricity and waste heat
Why are digesters getting a lot of attention today?
Odor complaints - encroachment of housing developments bordering farm land
Energy crisis (as in the late 1970’s)
Completion of de-regulation of Pennsylvania electrical utility companies
Biogas used for power production: decrease, meet or eliminate electricity purchases from power companies
Growing concern of greenhouse gas emissions
Nutrient management concerns
Why are digesters getting a lot of attention today continued:
Heat recovery utilization
Regulations for nutrient discharges from non-point sources
Reduces pathogens and weed seeds
Dried separated solids - bedding for animals
Separated solids - sold as bedding or soil amendments
Nutrient-rich effluent – lowers or eliminates fertilizer costs
Improved storage and handling characteristics of manure
Sale of Carbon Credits and Renewable Energy Credits (REC)
Green energy
Why are digesters getting a lot of attention today continued:
Pennsylvania’s Governor Edward G. Rendell’s Energy Portfolio Standards and Net Metering laws have allowed Pennsylvania farm-based digester electrical generators to produce “renewable energy” for the grid profitably. Net metering basically allows the farmer to sell its excess power to the grid at the retail generation rate.
Power production adds significant costs to the overall digester project, but without the power production capability these anaerobic digester systems would not be cost effective at the current $1M plus price tag.
Grants & loans from various agencies and programs for Pennsylvania farmers installing an anaerobic
digester manure handling system
• United States Farm Bill
• Pennsylvania Department of Environmental Protection (PADEP) Energy Harvest Grants
• United States Department of Agriculture (USDA) Environmental Quality Incentives Program (EQUIP)
• Pennsylvania Department of Agriculture’s Machinery and Equipment Loan Fund (MELF)
• Pennsylvania Governor Rendell’s Renewable Energy Portfolio Standards
These programs are in their infancy and long term success is unknown.
Carbon Credits & Renewable Energy Credits (REC)
Sale of estimated carbon credits for a 20 year period
(received a lump sum payment)
Environmental Credit Corporation, certifies the farm’s methane destruction and trades the carbon credits on the Chicago Climate Exchange
Other sources of capital to finance part of the digester system
Sale of Renewable Energy Credits (REC)
ACT 38 of 2005
Agriculture, Communities and the Rural Environment
ACRE
Creates a process for farmers to seek judicial review of ordinances believed to be restrictive of normal agricultural
operations. Farmers will have the ability to request the Pennsylvania Attorney General to review an ordinance
restricting agriculture that the farmer believes to be illegal.
The Pennsylvania Secretary of Agriculture and the Dean of the College of Agricultural Sciences at Penn State will
provide expert consultation regarding the nature of normal farming operations and practices in the Commonwealth.
Unique items and problems that have occurred on PA farms installing digesters
Brendle Farm - liquid chicken manure
•Water is added and mixed with the manure to make a slurry
•Irrigate the digested manure slurry
• Prevent clogging
Brendle Farm – pre-heat tank
• Added early in operation as a limestone grit and feather removal mechanism
Pressure relief valve attached to the flexible cover.
The designer of this AD system uses an emergency biogas relief assembly that is attached directly to the flexible cover to prevent over pressurization in the event the biogas piping gets clogged.
Brookside Dairy, Homer City, PA:
Penn England Farm, Williamsburg, PA: designed with a flat flexible cover to prevent wind damage.
Penn England Farm, Williamsburg, PA: heat recovered from the engine radiator is directed through the concrete floor to dry the separated digested solids.
Schrack Farms (Dairy)
This plug flow digester is designed with an offal pit for additional feedstock to boost methane production.
Schrack Farms - concrete and bolt delay (1 yr.)A major problem with the concrete sub-contractor
building the plug-flow digester tank on Schrack Farms delayed the entire project for almost a year.
The groove along the entire top edge of the digester was not cast properly. Also, bolts of two
different sizes were not cast in the proper locations.
In large pen swine houses, a dunging pattern is observed.
Pine Hurst Acres Danville, PA
Swine do not like to defecate where they sleep. These piglets show they prefer to sleep along the wall and defecate in the center of the pen.
Pine Hurst Acres
Complete Mix Digester
Raw Manure Digested Manure
1,100 pigs
1,100 pigs
3 m 3 m6 m 6 m 6 m
Pine Hurst Acres, Danville, PA
Manure Pits
(Meinen 2008)
(Meinen 2008)
Gases: ammonia, hydrogen sulfide, methane and carbon dioxide concentration levels were monitored and revealed not to exceed recommended maximum concentrations for either animals or humans (Meinen 2008).
A biogas website to communicate farm-based anaerobic digester information to the public (www.biogas.psu.edu) has been created at The Pennsylvania State University.
What is an Anaerobic Digester, History of Anaerobic Digestion, Types of Digesters (with case study examples from across the United States), AD Safety, Resource Listings of equipment, designers, financing and most recently, six Pennsylvania farm-based AD case studies were added to the biogas website.
Department of Agricultural and Biological EngineeringBasics of Anaerobic Digestion TerminologyTypes of Anaerobic Digesters * Complete Mix * Plug Flow * Covered Lagoon * Other Types or ModificationsCase Studies
Common Digester Misconceptions Consultants, Equipment Dealers and FundingSafety with BiogasResource LinksCentralized Digesters PSU Digester ProjectsContact Us
Biogas ProductionBiogas production using anaerobic (oxygen free) digestion is a biological treatment process to reduce odor, produce energy and improve the storage and handling characteristics of manure. A biogas production system must be specially designed and requires regular attention by someone familiar with the needs and operation of the digester. Associated manure handling equipment and gas utilization components are also required. The digester does not remove significant nutrients and requires an environmentally responsible manure storage and handling system. A well designed and operated digester will require modest daily attention and maintenance. The care and feeding of a digester is not unlike feeding a cow or a pig; it responds best to consistent feeding and the appropriate environmental (temperature and anaerobic- oxygen free) conditions. The earlier a problem in operation is identified the easier it is to fix and still maintain productivity. Thinking about a digester for your operation? Ask yourself these questions. Support for this website made possible by:Mid-Atlantic Regional Water Program Department of Agricultural and BiologicalCollege of Agricultural Sciences Engineering
Brendle Farm Type of farm: Belted, Caged LayerName of farm: Brendle Farm County: SomersetFeasibility Study: 1982 by Wayne Bogovich of USDA Natural Resources Conservation Service (NRCS) (Bogovich 2004)Digester designer: Bert and Dick Waybright, Gettysburg, PA Digester installer: Brendle FarmConstruction start date: Spring 1984 (designed in 1983) Date Digester became operational: June 1984Number of animals contributing manure to the digester: 72,000 laying hens Manure handling system: caged layers manure belt, augered to liquid mix tankType of digester: slurry loopDigester cover: flexible Digester temperature: mesophilic 95oFBiogas uses: operate the CHP unit to produce electricity and heat Biogas utilization equipment: engine generatorHeat Recovery Utilization: engine generator water jacket to heat the digester, pre-heat wash water for egg processing and to heat the egg processing area and the office. Power Purchase Agreement: Yes2008 status of digester: operationalInformation provided by: Robert and Michael Brendle, (2006 & 2007)
Farm NameYear
OperationalType of Digester
Animal Type
# Animals Contributing
CHP Unit
RatingHeat Recovery Utilization
DAIRY
Brookside Dairy
2006Modified Plug Flow (Slurry
Loop)Dairy 425 85 kW digester & hot water
Brubaker Farms
2007 Complete Mix Dairy 900 160 kW
digester & genset radiator air used to dry separated solids used for bedding
Dovan Farm 2006 Plug Flow Dairy 400 100 kW digester & hot water
Four Winds 2006 Plug Flow Dairy 500 130 kW digester & hot water
Hillcrest Saylors Farm
2006 Plug Flow Dairy 750 100 kW digester & hot water
Main Farm 2006 Complete Mix Dairy 500 90 kW digester & hot water
Mason Dixon Farm
1978Modified Plug Flow (Slurry
Loop)Dairy 2985 600 kW
digester & home heating
Oregon Dairy 1986Modified Plug Flow (Slurry
Loop)Dairy 385 65 kW
digester & farmhouse domestic hot water and home heating
Penn England 2006Plug Flow
(Mixed Loop)Dairy 800 160 kW
digester & hot water for milk parlor, genset radiator air used to dry separated solids used for bedding
Schrack Farms 2006 Plug Flow Dairy 650 200 kW digester & hot water for milking parlor
Wanner Pride-N-Joy Farm
2007Plug Flow Circular
(Slurry Loop)Dairy 400 130 kW digester & hot water
Farm NameYear
OperationalType of Digester
Animal Type
# Animals Contributing
CHP Unit Rating
Heat Recovery Utilization
SWINE
Beaver Ridge Farm
Design 2008 Complete MixFinishing
3000 130 kW digester & hot water
David High 1998Vertical Plug
FlowSwine
1200 22 kW digester & hot water
Mathis Farm Design 2008 Complete MixFarrow
to Finish 272 15 kW digester & hot water
Pine Hurst Acres
2004 Complete MixFinishing
4400 47 kW digester
Rocky Knoll LMD Partners
1985 Complete Mix
Farrow to Finish & food waste
1000 130 kW digester & hot water
BEEF & POULTRY
Brendle Farm 1984 Slurry Loop Layers 72000 65 kWdigester, pre-heat egg wash water for egg processing, heat egg processing area & office
Zimmerman 2007 Complete MixBeef /
Broilers1000 / 120000
175 kW digester & hot water
FOOD WASTE
Fairview Swiss Cheese
Construction 2008
mobilized film technology
cheese whey &
cone batter
NA Unknown
Boiler to produce steam and electricity for processing milk into cheese
Questions?
On-Farm Anaerobic Digestion Biogas Production in Pennsylvania – 30 Years
Deborah A. Topper Research Technician Patrick A. Topper Sr. Research Technologist
Robert E. Graves ProfessorThe Pennsylvania State University