Middlebury wastewater-to-energy proposal gains momentum

MIDDLEBURY — Developers of a proposed resource recovery center that would transform industrial wastewater into energy are now seeking the necessary state and local permits to build the facility off Middlebury’s Exchange Street.

A multi-million-dollar PurposeEnergy Inc. facility would be built on land at 183 Industrial Ave. owned by local businessman Tony Neri.

PurposeEnergy would use an anaerobic digester to extract energy from organic wastewater generated by Middlebury industrial park tenants, most prominently the Agri-Mark/Cabot cheese plant and Otter Creek Brewing. Energy extracted from the wastewater would be sold and distributed through the state grid via Green Mountain Power.

The technology is similar to Green Mountain Power’s “Cow Power” program, only the PurposeEnergy plant would process wastewater from beverage/dairy companies, as opposed to cow manure.

Eric Fitch, CEO of PurposeEnergy of Woburn, Mass., said he hopes to begin construction next spring on the project. But before that can happen, the plan must earn an air quality permit from the Vermont Agency of Natural Resources, state and local wastewater permits, a local variance and — most critically — a Certificate of Public Good from the Vermont Public Utilities Commission.

Fitch has filed his air quality permit application and has drafted paperwork for the state and local wastewater permits. But before he files them, he wants to negotiate a deal to connect to Middlebury’s wastewater treatment plant.

And that’s where it gets tricky.

Middlebury has a wastewater usage fee of $6.78 per 1,000 gallons used. The town also levies a surcharge for “high-strength waste,” containing more than 250 milligrams per liter for biological oxygen demand (BOD) and Total suspended solids (TSS).

PurposeEnergy officials would like to design their plant for a capacity of 150,000 gallons per day, but they don’t believe their operation should pay the conventional municipal charges for the wastewater it sends to the sewer plant. That’s because the wastewater that the PurposeEnergy plant treats will have been significantly stripped of its organic waste (BOD) content, thus making it easier for the sewer plant to process, according to Fitch.

So Fitch is proposing a fixed connection fee of $15,000, which he called a starting point for negotiations with the town. He argued the town has in the past given breaks to other large industrial users of the sewer plant.

“Looking at it from the capacity of the treatment plant, you could make an argument we’re actually freeing up capacity in the treatment plant and not taking it,” Fitch told the Middlebury selectboard at their Tuesday meeting. “We’re addressing the bottleneck constraint of the plant — being the organic load — rather than the hydraulic capacity.”

Selectboard members listened to Fitch’s pitch, and have asked town staff to examine it further in hopes of giving PurposeEnergy a response by Sept. 10.

“We need to know we’re doing our due diligence on the town’s side,” Middlebury selectboard Chairman Brian Carpenter said.

Meanwhile, Fitch is looking for other potential business partners for the PurposeEnergy plant — including Vermont Gas Systems (VGS), and industrial park neighbors seeking to cut their heating bills.

“We have a co-generation unit — it’s combined heat and power,” Fitch explained. “While it produces a Megawatt (of power), it also makes between 3 million to 4 million BTUs per hour in recoverable thermal heat available. We’re trying to figure out how best to use that thermal energy. In a discussion with Vermont Gas, they suggested we give them the thermal energy, and they would install a district heating loop in the industrial (park).”

Imagine a hot water supply-and-return pipe. Customers with a steady demand for thermal energy could use this resource as an alternative to using fossil fuels. And Fitch believes Vermont Gas could help deliver the product.

“The gas company is incentivized by the state to deliver renewable energy, but there aren’t many opportunities for them to do that,” Fitch said. “If they do this district heating supply, the pipes will have hot water in them instead of natural gas.”

He called the thermal heating project, “very much in the Vermont Gas business model. They’re more likely to be able to make this investment and get a payback on it for a price they can charge the cheese plant a low rate for this energy.”

Vermont Gas officials confirmed their interest.

“Vermont’s energy landscape is changing — and quickly — and VGS is committed to being a leader in the change,” said Vermont Gas Communications and Brand Manager Beth Parent.

“The State’s ‘90-percent renewable by 2050’ goal has sharpened our focus …VGS is working on the potential to deliver the waste heat from the Purpose’s electric generator to commercial customers on Exchange Street, via hot water pipes, like a district energy system. We are still in the planning phase and hope that we can finalize a plan in the coming months.”

Reporter John Flowers is at johnf@addisonindependent.com.

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