BioCycle February 2005, Vol. 46, No. 2, p. 30
An analysis of how large the industry has become also reviews the technology options and feedstocks processed.
Richard Mattocks and Richard Wilson

AFTER a spotty, educational past, the numbers of digester installations have increased dramatically since the many successful AgSTAR demonstration projects of the 1990s. Manure and food waste codigestion systems are now being installed. Community digesters are not only being evaluated but also actually constructed. The added demand has drawn a large number of designers and developers, increasingly from outside North America. Government support has increased remarkably, as interest has spread outside of animal production facilities to marketers, utilities, lending institutions, public service groups as well as regulators. Digesters have morphed from power generation to a waste management technique that pays for itself.
This report reviews trends in the manure digester industry in three general categories: Recorded history; What is happening at the moment; and A brief glance into the crystal ball. Our remarks are limited to manure and organic waste digesters with no discussion of sewage treatment plants, industrial treatment plants, or solid waste digesters and landfills. To better understand the environment into which the digester industry is expanding, let’s look at renewable energy market developments:
At an October 2004 conference, a presentation by National Renewable Energy Laboratory staff states that the time for renewable is now because: Nearly 20 companies market certificate (REC) products; price ranges from $0.01 to $0.25 kWh; in a single year, about 6,000 customers bought certificates; and many purchasers are large nonresidential who have supported major developments in states like Pennsylvania and West Virginia. One innovative company – Native Energy in Vermont – is purchasing emission reduction credits for sale to clients nationally.
HISTORIC PERSPECTIVE
While archeological evidence suggests that some form of digesters were in use before the beginning of the Christian era, widespread use is a phenomena of recent times. Digesters are recognized to be well distributed, decentralized power generation sources; contributors to the revitalization of the rural economy; cost effective; and complementary to current energy sources. Manure digestion systems are more than energy sources since they improve environmental conditions.
One of the first American manure digesters was constructed in Iowa in 1972 on the McCabe hog farm, operating until 1999 when destroyed to make way for a county road. The Fairgrove Farms digester in Sturgis, Michigan ceased to operate in 2002 after over 20 years of operation when the dairy sold the herd. Mason Dixon Farms in Gettysburg, Pennsylvania is building another digester now, to make a total of four to be functioning, having constructed their first in the 1970s.
During the 1970s oil crisis, significant government funds were made available for renewable energy. During the period, many manure digesters were constructed for energy production. Unfortunately, there was little on-farm digester experience upon which to draw. Most of the work was prototype development based on adaptation of digester technology appropriate to other industries. Of the 140 or so digesters constructed during the 1970s renewable energy “hay day”, less than half were actual production facilities, with the remainder in research facilities. One firm constructed 20 facilities, all of which failed. Of all the systems built during that period, about 85 percent failed or were otherwise taken out of service. The industry learned much from the effort as reported in a 1998 Jack Rozdilsky paper (Michigan State University) in which he concludes “Digesters can be a feasible option when considering their [animal production facility] abilities for reducing waste treatment and disposal costs, providing a cost-effective way for complying with environmental regulations, and also producing energy. In terms of biomass resource availability and current technological capabilities, there is much room for expansion of the use of farm-based anaerobic digesters in the Midwestern United States.”
Experiences with the 1970-1980 digester industry experiment resulted in firmly embedded memories, not only in the animal production industry, but also in the lending and utility industries, as well as academia and regulatory bodies. There were successes, notably Mason Dixon Farm and Frey Dairy in Pennsylvania, Cooperstown and Curtin Brothers in New York, Fairgrove in Michigan, McCabe in Iowa, Langerwerf and Sharp in California. But the failures were more clearly remembered. Government financial support for digestion ended, energy production was the main goal of digesters and energy remained cheap. Very few digesters were constructed in North America between 1985 and 1995.
While the industry languished in North America, manure digestion systems became much more widespread worldwide: several million operating in China; several hundred thousand in India; and over a thousand in Europe. Installations increased remarkably in the western world since the strong Danish Government commitments toward the technology in the late 1980s.
CURRENT STATUS
The tide has changed.
USEPA AgSTAR constructed over a dozen demonstration systems in the 1990s – each one operating satisfactorily. The most notable are the AA Dairy digester in New York, winner of the 1999 Governor’s Environmental Award, and the Haubenschild Farm system, winner of numerous awards. Langerwerf Dairy, operating a digester since 1983, has had a near 94 percent “uptime”, processing virtually all manure produced. The success stories became hard to deny.
Manure digestion systems are receiving broad support. Iowa Pork Producers Association, Alliant Energy, the Iowa Agriculture Innovation Center, the Iowa Farm Bureau Federation, Iowa State University Extension, and the Midwest CHP Application Center sponsored a recent Midwest Digestion System Conference. A recent study of digestion systems in the Midwest was sponsored by the Wisconsin Milk Marketing Board, East Central Energy, WE Energies, the Black Hawk Hills Resource Conservation and Development Area, Focus on Energy and the Great Lakes Regional Biomass Energy Program. U.S. digestion systems were reviewed at the St. Louis AgSTAR 2004 conference.
Upright mixed metal tank, concrete plug flow, mixed plug flow and intermediate mix digester designs have predominated since the 1970s. Covered lagoons, mixed and even mixed heated covered lagoons became more common nationally. Community digesters have come into use in Oregon and southern California. There are an increasing number of manure digesters that are receiving food waste for codigestion.
For over a year, the centralized digestion facility along the Oregon coast operated by the Port of Tillamook Bay (POTB) has been treating the manure of 2,000 cows from as many as nine dairies. After the expected shakedown period, the plant has been on a regular operational mode. Fiber recovered from the digestion facility has been good business. Sales to a Portland, Oregon potting soil manufacturer have been done at a discounted price principally due to transportation costs. Revenues from fiber sales offset costs of transporting manure and treated liquid nutrients between the farms and the centralized digester. A recent study by Ron Alexander for POTB indicated a greater economic potential for the fiber once it was stabilized, dried, blended and bagged. The fiber is undergoing stabilization trials now. POTB has purchased equipment, including a used drum drier, to test the bagging concept.
The number of designers available for service in North America and Europe has increased significantly. More than 60 firms claim manure and organic waste design capabilities. Of recent new entries into the U.S. market, a Danish style complete mix system is in construction on a Wisconsin dairy as part of the Microgy Dairyland Utility agreement.
INCREASED NORTH AMERICAN GOVERNMENT SUPPORT
In Canada, the government of Ontario will invest $1,604,603 in an integrated anaerobic digestion facility that will convert biogas from manure into heat and electricity. The Lynn Cattle Company Inc. will produce substantial amounts of electricity – enough to power its own operations as well as to sell surplus electricity on the market. The Municipality of North Middlesex has agreed to purchase 2,500 megawatt-hours of electricity annually, enough to power all municipally owned property for the year, making it the first green-powered municipality in Canada.
Washington D.C. has placed a high priority on creating new sources of renewable and biomass energy. In 2002, funding was made available for digester and other renewable energy installations. The 2002 Farm Bill established the Renewable Systems and Energy Efficiency Improvements Program under Title IX, Section 9006. This U.S. Department of Agriculture program provides $23 million per year in direct financial assistance for renewable energy and energy efficiency projects in rural America. More digester projects were funded in 2004, with 35 percent more money provided to digester installations. The average cost per digester increased 10 percent to just over $1,000,000 per installation.
The Value-Added Producer Grants (VAPG) (formerly known as the Value-Added Development Grants) were authorized by the Agriculture Risk Protection Act of 2000 and was amended by the Farm Security and Rural Investment Act of 2002. VAPG is providing funding for manure digestion related projects among the 97 projects approved in 34 states, totaling over $13.1 million.
California recently started another two manure digestion installations under its well-funded manure digestion program. Information supporting and expanding on the following passages may be found on the Western United Resource Development Inc., (WURD) website. The program “is developing manure methane power production projects on California dairies through the Dairy Power Production Program” (DPPP) which approved a total of $5,792,370 for 14 projects. WURD estimates a total generating capacity of 3.5 megawatts. “The purpose of DPPP is to encourage the development of biologically based anaerobic digestion and gasification (“biogas”) electricity generation projects on California dairies. … This program, funded by the California Energy Commission, will help California dairy farmers deal with their skyrocketing electrical bills and help take the load off the state’s electrical grid. The $10 million grant program is part of Senate Bill 5X, to ensure the immediate implementation of energy efficient programs to reduce energy consumption and assist in reducing the costs associated with energy demand.”
The program offers aid in two methods: A cost share of up to 50 percent of a dairy producer’s capital costs in constructing the digester, or reimbursement of up to 50 percent of the capital costs through electricity generated. Low interest loans to help with the remaining costs are available under the California Renewable Energy Loan Guarantee Program (CRELGP). Minnesota also has an aggressive development program.
Several prominent state programs in support of manure digestion are in New York (NYSERDA) and Pennsylvania (Energy Harvest Grants). Oregon Department of Agriculture also has varied forms of available financial assistance. The Tillamook project in Oregon is installing a drier and bagger for the fiber exiting its centralized digester that treats manure from 2,000 cows.
CRYSTAL BALL AND ORGANIC WASTE DIGESTER MARKET
No known market study has been completed to ascertain the size of the animal waste digester market. One company that has made a public statement of the market size, Microgy, reports on its website that there is currently a $4 billion market that they expect to expand to an eventual $13 billion market. The authors’ opinion is that the market is about $2.5 billion to $3.5 billion, based on EPA projections that there are as many as 4,000 animal production facilities appropriate for digestion, and the average cost of a digestion facility in the $500,000 to $1,000,000 range.
Richard Mattocks and his company, Environomics LLC, are based in Salt Point, New York. rpm@waste2profits.com. Richard Wilson is at Morrisville College in Morrisville, New York. This paper is based on a presentation by Mattocks at the BioCycle Fourth Annual Conference on “Renewable Energy From Organics Recycling,” in November 2004 in Des Moines, Iowa.
DIGESTION TECHNOLOGY IS NOW INTERCONNECTED WITH OTHER INDUSTRIES
RESURGENCE and broad based support of anaerobic digestion is because it is being viewed as more than electric generation alone. The technology has become interconnected with other industries. Digestion is becoming an enabler.
Factors influencing the expansion of the industry market include: increased technical reliability, growing concern of facility owners about environmental quality, increased number of federal and state funds available for cost share, and emergence of new state energy policies (net metering and RPS).
Fibrous solids recovered after digestion is in wide use as bedding and a compost feedstock, removing one cost of doing business.
The trend is towards a more thorough exploitation of resources. Manure and organic waste will not merely be land disposed or treated prior to disposal. We see a continuation of the current trend towards codigestion of various organic waste streams. There is a synergy in blending of complementary wastes for digestion. Energy is extracted, nutrients are converted to forms better utilized, and waste water treatment plants loads are reduced. As scale increases, there is additional flexibility in adopting more sophisticated nutrient recovery and concentrating technologies, approaches out of the technical and financial reach of even larger production facilities.