Pilot biogas project at Massachusetts landfill site complete

By Katie Fletcher | October 10, 2014

A ribbon-cutting ceremony was held earlier this week at the Crapo Hill Landfill site in Dartmouth, Massachusetts, for the startup of CommonWealth Resource Management Corporation’s pilot-scale anaerobic digestion (AD) project. CRMC leases the landfill’s land from the New Bedford Regional Refuse Management District, and has other commercial arrangements with the landfill owner to make the project possible. “Those arrangements allow us to develop, own and operate this project, which not only benefit us and the environment, but also the landfill,” said Anton Finelli, CRMC principal.

The AD facility will produce biogas as a supplemental fuel to a preexisting 3.3-MW, landfill gas-fired electric power generating facility on the site owned and operated by a CRMC subsidiary. This was one of the reasons the company decided to bring a digester on site. According to Finelli, the project helps assure continued available fuel supply to the existing landfill gas project in the face of emerging environmental policy regarding commercial food waste in Massachusetts.

The ban, regulated by the Massachusetts Department of Environmental Protection, requires commercial food waste generators of at least one ton of organic material per week to donate or repurpose useable food instead of sending it to the landfill. Any waste that could not be donated would have to be repurposed through methods such as composting, anaerobic digesting or animal feed. A grid-connected, landfill gas-to-energy facility with the prospect of receiving fewer organics became a concern. The company took the concern and developed a strategy. CMRC’s interest in their long-term fuel supply combined with the company’s desire to demonstrate that AD could be a cost-effective option for management of organics at an already exiting waste management facility, justified the project’s construction.

The bioenergy facility is the first of its kind at an operating Massachusetts landfill, and the first developed in the state to produce biogas for use in a preexisting landfill gas-to-energy facility, according to a statement. “We’re confident the project can serve as a model for similar projects elsewhere in New England,” Finelli said.

The project is being developed in two phases. The pilot phase, which is now completed, will accept approximately 3,000 gallons of targeted organic wastes per day in a digester with 100,000 gallons of holding capacity. The biogas produced with this operation is expected to be utilized within the current power generating capacity of the existing landfill gas facility. “We will run it in a pilot phase for as long as it takes to convince ourselves and any of the other stakeholders that it will make sense economically and environmentally to gear up,” Finelli said.

If proven successful, the pilot scale project will be expanded up to 30,000 gallons per day of feedstock in a digester with 1 to 1.2 million gallons of holding capacity. The biogas anticipated to result from expansion could increase the generating capacity of the existing landfill gas-fired power plant from 3.3 MW to 4.1 MW.

Finelli describes the phasing of the project as a walk-before-you-run process. The company is confident in their technology, but there are various factors that will be considered before expansion—for example, how the solid waste marketplace reacts to the new regulations for one. Another component is looking at the results from the facility testing beneficial uses of some portion of the residuals from the AD process within the existing operations. One of the demonstration aspects is the inoculation of a closed portion of the landfill with some of the spent digestate from the digester. “In our case what we’re going to do with some of the liquid digestate is send it back to the landfill; inoculate a closed portion of the landfill with this material to see to what extent that added moisture and bacterial life accelerates the continued generation of landfill gas in that closed portion of the landfill,” Finelli said.

Other demonstrations include the provision of a biologically enriched admixture for yard waste composting, and displacing water as the source of moisture in the production of daily landfill cover material.

The project was funded partially by grants and loans from the Massachusetts Clean Energy Center, the Massachusetts Recycling Loan Fund and the USDA Rural Development agency. “We were fortunate to receive help from a variety of sources,” Finelli said. “Although this is a privately developed, owned and operated facility, it’s made possible through a cooperative partnership with a public entity and supportive communities.”