August 19, 2009 | General

Regulating Codigestion Plants

BioCycle August 2009, Vol. 50, No. 8, p. 35
States grapple with how to regulate codigestion facilities as these projects cut across multiple agencies with responsibilities for different environmental and public health rules.
Diane Greer

IT TOOK several months, but Schmack BioEnergy finally received approval from Ohio Environmental Protection Agency (OEPA) to add food waste to its digester, which processes sewage sludge at the City of Akron, Ohio’s wastewater treatment plant. “When we went to Ohio EPA and said we wanted to add food waste to the digester, they didn’t have a process in place on how to manage it,” explains Bruce Bailey, Vice President of Technical Affairs at Schmack BioEnergy in Cleveland, Ohio.
The permitting and regulation of biosolids (treated sewage sludge) is handled by the OEPA’s Division of Surface Water through the U.S. Environmental Protection Agency’s National Pollutant Discharge Elimination System (NPDES) permit program. That program is part of the Clean Water Act, which regulates point sources discharging pollutants into water.
“But when you start adding food waste to the system, then the OEPA Division of Surface Water starts scratching their heads, and has to reconsider the best way to handle the process,” Bailey says. That’s because the Surface Water Division does not regulate food waste. In Ohio, food waste falls under the Division of Solid and Infectious Waste Management.
Ohio is not the only state grappling with how to regulate codigestion facilities, which process multiple types of organic feedstocks. For many states this is a new issue that cuts across multiple regulatory agencies with responsibilities for different environmental and health aspects of the process.
Driving the need for new regulations are facility operators and project developers who view codigestion as an effective means of boosting biogas production in anaerobic digesters, providing the opportunity to reduce on-site fossil fuel usage and/or to gain revenues from renewable fuel sales. Facilities also can collect tipping fees from organic waste producers, such as food processors.
“Regulators recognize this is an emerging industry,” says Joe Goicochea, environmental specialist with the OEPA’s Division of Solid Waste Management. “But states need an opportunity to feel comfortable with what they may view as unforeseen issues.”
Regulators have two primary concerns about codigestion, explains Chris Voell, Program Manager of USEPA’s AgSTAR. “First, they don’t want inappropriate materials to be put into a digester that may cause health concerns. An example might be animal mortalities.” This is the case in Michigan. “Farms or centralized systems might not know what they are accepting,” says Norma McDonald, operating manager at Cincinnati-based Phase 3 Renewables. “There is a potential for abuse of the system where contaminants could either inadvertently or knowingly get introduced into a digester.”
Second, states are concerned about nutrient management issues. “There are strict nutrient management plans that installations have to follow when applying nutrients to the land,” Voell says. “When you start codigestion, this needs to be managed appropriately.”

Operators and project developers are finding states unsure of the best way to regulate codigestion facilities. “There is a lot of overlap,” Goicochea says. In Ohio, three separate regulatory programs potentially have a role in regulating codigestion. The solid waste program is interested because codigesting food wastes could be viewed as a form of composting. The surface water program, as administrator of the federal NPDES program, has a role. If the facility requesting the permit is a confined animal feeding operation (CAFO), then the Department of Agriculture (DOA) has a role.
Ohio has developed a framework for one regulatory program to take the lead but then give the others an opportunity to comment on the permitting process, Goicochea says. This approach benefits both the regulators and the regulated entity, because the latter isn’t burdened with obtaining multiple permits. “From our perspective, expending state resources to have three programs permit the same facility for overlapping reasons was a waste of resources,” he explains.
Three key scenarios now define which program takes the lead in permitting codigestion facilities. If it is a CAFO, DOA takes the lead. When biosolids are involved, the surface water program takes the lead. When a facility is not located on a CAFO and not incorporating biosolids, then the solid waste program is the lead agency.
“Our solid waste program requires that they [the codigestion facilities] obtain solid waste permits,” Goicochea says. But due to the flexibility of the state’s statutes, the program can exempt digesters from obtaining a permit if they are permitted through the DOA or the surface water program. “We are reiterating this through a rule, which basically says if you obtained a permit through one of those programs you are not subject to the solid waste chapter except for the digestate that comes out the back end,” he adds.
Iowa is taking a different approach, setting up a one-stop shop for compliance issues. “When someone comes to us and is interested in building a digester, we get all the regulators together to understand what the farmer or community-based system is proposing and answer all the applicant’s questions at one time,” explains Allan Goldberg at the Iowa Department of Natural Resources (DNR).
“From my experience, Iowa is an excellent role model for other states,” McDonald says. “You have the DNR, DOA and the soil and water conservation folks all seeing the benefit of codigestion and working collaboratively on behalf of the different projects. This is a much more proactive approach, similar to what you have been seeing in Europe for years.”


When Kevin and Daryl Maas, founders of Farm Power Northwest, decided to build a community digester in Washington State to process manure from dairy farms and food waste, they ran into problems immediately with permitting. “No one was really sure who had jurisdiction and they were not quite sure how to respond,” Daryl Mass says. “Muddling your way through the existing rules and trying to figure out who you should talk to was really costly and time consuming.”
The Maas’ first digester, located near Rexville, Washington, will take in waste from 1,500 cows at two adjacent dairies. Manure will be pumped to the facility, located on land leased from one of the farms. Food waste from processing facilities will be added to boost biogas production and provide revenues from tipping fees. When completed in August, the Farm Power Rexville digester is expected to produce 750 kWh/day, enough to power 550 homes.
“We are a manure digester taking in food wastes, but they wanted to treat us like a solid waste handling facility,” Maas says. “They know how to permit a solid waste handling facility but they do not really know how to permit an organics recycling facility.”
After talking at length with regulators, Maas found that there was not enough flexibility in the existing regulations to change how his facility was permitted. So he wrote to his state senator, Mary Haugen. She introduced Senate Bill 5797, which allows anaerobic digesters to operate under an exemption from solid waste handling permits and accept other organic materials that are not manure or don’t come from a farm. The bill was signed into law on April 22, 2009.
Facilities need to comply with a specific set of requirements to satisfy the exemption, says Kara Steward at the Washington State Department of Ecology. Digesters must take at least 50 percent manure and up to 30 percent organic materials that are not manure. “The remaining 20 percent, which is not specified, will most likely be manure. The 30 percent is what digester builders said they need to get the methane production to make the projects work economically.”
The 50 percent is from another statute giving tax exemptions to anaerobic digesters that process 50 percent or more manure. Only preconsumer food waste qualifies under this exemption. Material must be fed into the digester within 36 hours of being received by the facility. “We are worried about piles of putrescible organics backed up for long periods of time,” Steward explains.
If digester effluent is sent back to the dairy, then the dairy must have an updated nutrient management plan that accounts for the higher nutrients in the effluent due to the addition of the organic materials. Solids not going back to the dairy need to be composted, pass composting standards or be prepared in an approved manner.
With the new regulations in hand, Maas is confident he can proceed with plans for additional community digesters. “We are designing projects in three counties in Washington and one in Oregon,” he explains. “We want to make community digesters work for farms that are too small to do it themselves.”

Several states are trying to make it easier for farm-based digesters to process other organic wastes. In New York State (NYS), farms that manage their own manure or manure from other farms and have a CAFO permit from the Department of Environmental Conservation (DEC), Division of Water, don’t need a Part 360 permit for organics recycling from the Division of Solid & Hazardous Materials, says Sally Rowland, an environmental engineer at NYS DEC.
“Farms may take in up to 10 percent food processing waste by volume of the digester under what is called a registration under 360,” she explains. “You fill out a form and basically tell us where you are and what you are doing.” Farms going over 10 percent by volume are required to get a permit under 360. Currently, only one farm has a Part 360 permit while a few others are operating under registrations. Adds Jacqueline Lendrum, research scientist, Division of Water, NYS DEC: “Farms codigesting other organics must have the land base to handle the additional nutrients, or an export stream that they are composting or selling as compost.”
DEC is in the midst of revising Part 360 to remove overlaps with CAFO regulations when it comes to digesters, adds Rowland. Regulations may be changed so CAFOs processing over 10 percent food wastes do not need 360 permits.
In Ohio, a few farms have asked the DOA about permits for codigesting other organic materials. Ohio DOA is working with Ohio EPA to allow certain types of materials that increase methane production to go into the digesters. Essentially DOA does the permitting for the farm and OEPA allows the material to go to the digester from the food processors. Food processors must have a means for disposing of wastes, which is approved by the OEPA, whether it is a landfill, rendering plant or digester.
Digesters going through DOA permitting can take up to 25 percent by volume of organic wastes, as long as the facility complies with its nutrient management plans. Approved organic materials include preconsumer food wastes, grease trap wastes and similar organics. Biosolids, septage or similar types of wastes are not allowed. Beyond 25 percent, OEPA becomes involved in the permitting.
Michigan’s Department of Environmental Quality is in the process of rewriting permit rules and is considering adding language to allow processing of other organic feedstock in digesters without a special permit, says Norma McDonald.

Meanwhile, Schmack Bioenergy is moving ahead with plans for codigestion facilities in other Ohio cities. In mid-June the company received all of its OEPA permits to build a digester in Columbus to process biosolids along with food wastes, fats, oils and grease (FOG) and other suitable waste streams, Goicochea says.
Like Akron, the Columbus facility will use a high-solids digester developed by Schmack Biogas AG, Germany. (For a detailed description of the Akron facility, see “Processing Biosolids Via A High Solids Digester,” BioCycle September 2008.) Food wastes will come from local processors. Between 3 to 4 million gallons/year of FOG will be received.
“Wastes will be taken into a reception pit or, if it is a liquid, pumped into holding tanks,” Bailey says. “This is so we know what we are feeding our digesters. They perform better if you feed them on a regular basis with a steady diet.”
Effluent from the digesters will go back to the head of the wastewater treatment plant. “We are exploring alternative ways of handling the liquid portion because it carries nutrients,” Bailey says. Solids will be dewatered and then pasteurized to produce value-added products. The company plans to develop projects in additional states. “Every state has a slightly different view of regulations for mixing food waste in an anaerobic digester,” he adds. “As long as you are talking to the agencies and are up-front about your goals, you generally can work with them on what they need to protect the environment.”

Diane Greer is a Contributing Editor to BioCycle.

Sign up