Food-to-electricity plant envisioned
Decaying restaurant scraps would generate methane gas to burn for power
When it comes to food scraps, one man's trash is another man's treasure — or in this case electricity.
The Easton Area Joint Sewer Authority is designing a system that would use food scraps from restaurants around the Lehigh Valley to generate electricity to power the entire sewer plant on Route 611 in Easton. Sewer plant officials say it's the first project of its kind in the Lehigh Valley.
The project, which officials estimate would cost $1.5 million to $2 million, could shave about $450,000 off the sewer plant's yearly electric bill once it goes online. The savings could be invested back into the facilities, which require frequent updates.
Over the summer, the Easton Area Joint Sewer Authority paid $75,000 for engineering and feasibility studies on the project. It's too early to say when the project might begin, but the authority hopes to start the design phase in the spring, said Dave Hopkins, Easton's director of public works and a member of the sewer authority's board of directors.
The authority, which serves six municipalities, has used methane gas from sewage processing to heat the plant since the 1990s, Hopkins said.
The food waste would supercharge that process by providing material that's easy for bacteria to quickly digest. The byproduct of that digestion is methane, which can be harnessed to start producing electricity, he said. The plant already produces 140,000 cubic feet of methane per day. That
amount could double if the authority starts collecting food waste, Hopkins said.
Becky Bradley, executive director of the Lehigh Valley Planning Commission, said she’s not aware of any other local utilities that process food scraps, though converting methane into power is a popular option, particularly for local landfills.
The Lehigh County Authority does capture methane at its Kline’s Island treatment plant, though that operation does not use food waste, said LCA Communications Manager Susan Sampson. That operation produces 35 to 50 percent of the power needed to run the plant, she said.
Under the Easton plan, the sewer authority would construct a small plant near its anaerobic distribution tanks where the food waste could be dropped off. As the food decomposes, it releases methane that can be burned to create electricity.
Food waste is becoming a commodity, and studies the sewer authority conducted over the summer show there’s plenty of restaurants and breweries in the Lehigh Valley to offer a continuous supply.
Restaurants would need to bring the food waste to the sewer authority for processing, but the sewer plant is likely a closer hauling location for them, and the price could probably be negotiated, said Robert Lammi, vice chairman of the Easton Area Joint Sewer Authority.
The process of converting leftover food into electricity is already popular in Europe, and has started to make its way to the United States.
In the United Kingdom, Keynsham, a town of 16,000 residents, opened a plant in 2016 that uses anaerobic digestion to generate electricity from food waste that comes from local businesses and homes. The plant provides enough electricity to power 80 percent of the town’s homes.
Closer to home, RNG Energy Solutions, a developer of renewable energy projects, announced over the summer it would be partnering with Philadelphia Energy Solutions, which operates a South Philadelphia refinery complex, to build a $120 million digester that can convert more than 1,100 tons of food waste a day into methane gas, Philly.com reported.
According to the Food and Agriculture Organization of the United Nations, “food loss and waste amount to a major squandering of resources, including water, land energy, labor and capital, and needlessly produce greenhouse gas emissions, contributing to global warming and climate change.”
Roughly one third of the food produced in the world for human consumption every year — about 1.3 billion tons — gets lost or wasted, according to the FAO.
The gases produced by that food, however, can be harnessed through anaerobic digestion and burned to produce electricity and heat. Anaerobic digestion involves using organisms in an oxygen-free environment to break down biodegradable material, like food waste.
One of the end products is “biogas,” which is combusted to generate electricity and heat, according to the American Biogas Council.
The Easton Area Joint Sewer Authority worked with students from Manhattan College in Riverdale, N.Y., who collected samples and determined what it would take to jump-start the methane production already going on at the plant.
Authority officials also enlisted Hazen and Sawyer, an engineering firm with headquarters in New York, to deter- mine if there would be enough food waste available.
In 2017, restaurants in the Easton area started providing food scraps to be turned into commercial compost. That project is run by Northampton County and is separate from what the sewer authority is proposing, Hopkins said.
Even with the compost program in place, Hazen and Sawyer said there was enough interest from local and regional restaurants and breweries to proceed.
It’s estimated that it would take about 12,000 gallons per day of liquid food waste to generate enough electric to power the sewer plant.
“When we first started this study, the first question we had was, ‘Do we have enough of a market for this?’ We found there was a lot of waste out there that would meet our needs and probably exceed it,” Lammi said.
It’s too early to say whether the cost savings would be passed along to customers.
The savings would most likely be used to update the plant, which processes 10 million gallons of sewage per day from Easton, Palmer, Forks, West Easton, Tatamy and Wilson. The facilities are owned by Easton with each municipality paying into the system.
“Because the main part of the plant was built in the 1950s, over the years we have had to spend quite a bit of money to modernize things,” Lammi said. “It’s a high maintenance type of operation.”
Hopkins said the sewer authority invested $16 million into the plant within the last four years. Upgrades included rehabbing the plant’s primary tanks, installing new pipes, pumps and gear boxes.