Hatch Hill Landfill Gas to Energy

Augusta is home to Hatch Hill Landfill, which services Maine’s capital city of 19,500 residents and eight surrounding communities with approximately 21,500 residents. In early years of operation, the methane gas produced by decomposing trash was released into the air. To reduce environmental impact, an underground system of pipes was later installed to collect methane and burn it off by flare, with some gas still released directly into the air through passive vents. In seeking a more environmentally friendly approach, city officials hired Woodard & Curran to determine if the landfill’s decomposing trash produced enough methane gas to fuel a 550-kilowatt generator. 

Harnessing the power 

With the resources available, new gas wells were installed to collect and transport methane through 1,700 feet of 8-inch underground pipe to a gas dehydration system near the facility’s operations building. A dehydration skid removes moisture and other contaminants from the collected methane. Extracted condensate goes to an on-site leachate holding pond, which is then pumped to the city’s wastewater treatment facility. Once treated, the methane is heated and released at the proper temperature to fuel the generator. 

The generator feeds electricity into the local utility provider’s grid under a net metering agreement with the city. The credit will be used to offset electric bills for landfill operations and nine city properties that cost the most to power, including: City Center, Augusta Civic Center, Cony High School, Capital Area Technical Center, two of the city’s four elementary schools, the police station, Lithgow Public Library, and Buker Community Center. Within 11 years, the $3 million project is expected to recover the investment through the reduction of the City’s energy costs. In 17 years, Augusta anticipates a return on investment of $1 million. Additionally, the methane collection and power generation system has reduced nuisance odors and greenhouse gas emissions.   

The project also included construction of a 1,490-square-foot structure to house critical electrical components required for net metering, including the CT meter, switchboard, and SCADA controls. This facility houses an office and breakroom for staff and provides space for the public to learn about the project.

Happier neighbors, happier environment

The new collection system, which employs gas wells, extracts more landfill gas than the previous perforated pipe system alone, collecting and utilizing the gas that would otherwise escape the landfill. In 2018, a geomembrane cap placed over an additional 7-acre portion of the landfill. These measures have reduced fugitive odors, which previously prompted neighborhood complaints. 

Additionally, the methane-to-energy system is reducing environmental pollution by limiting the amount of methane escaping the landfill. Methane is a powerful greenhouse gas, 84 times more powerful than carbon dioxide in the first two decades after its release. The generator produces approximately 500kwh of power when operating at full capacity, offsetting other power generation sources. The city will also harness waste heat from the generator to keep the Operation Building safe and minimize maintenance this winter. A radiant heating system was installed, designed to melt snow and ice on nearby concrete sidewalks and to prevent the truck scale from freezing when winter sets in. 

“For all the years W&C has been working at the Billerica WRRF, we have had amazing experience with your company. Whether it is implementing upgrades and going over all the little details, collaborating with industries in town, or working with the EPA on multiple levels as we deal with the permit, aluminum audit and the industrial pre-treatment audit, you have helped us navigate tough issues successfully.”

Jeff Kalmes, Superintendent, Billerica Water Resource Recovery Facility