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Reports find waste-to-energy plan feasible

Reports find waste-to-energy plan feasible

Consultants hired to evaluate the feasibility of the city sewer authority’s $44 million waste-to-energy plan said the project is technically sound but only “marginally” economically feasible.

In a presentation before the Water Pollution Control Authority board, financial consulting firm HDR said the plan to power Stamford’s water-treatment plant through gasification of dried wastewater sludge would eventually net about $2.5 million over a 20-year period. The draft report concluded the project “could provide renewable energy and an economic benefit” to the city, as long as it is “technically feasible and can be successfully completed.”

In a separate report, technical management consultants AECOM said they felt the project was “technically feasible as defined,” adding that gasification technology “holds great promise in reducing energy use at wastewater treatment facilities and has the potential of reducing the overall environmental impact” of such facilities.

Gasification is a process for extracting energy from organic materials by heating the material at high temperatures with oxygen or steam. Though the method was first developed in the 1800s and has since been used on an industrial scale to produce electricity using coal or wood, AECOM said Stamford’s project is the first it is familiar with that would try to produce power through gasification of biosolid waste.

The WPCA hired financial and technical consultants to review the waste-to-energy plan last year after it came under criticism from city residents who said Stamford should not be spending millions on an untested technology.

Under the proposal, the WPCA would first substitute wood chips for natural gas to fuel its current waste sludge drying system, which produces “biosolid” pellets the city sells to a contractor as fertilizer. In a second phase, the sewer authority plans to install generators that would run on energy produced from gasification of the pellets, providing fuel for the plant’s overall waste-treatment operation.

Despite the generally positive evaluations, critics of the plan who pushed for the reviews said they are still wary of the project. Lou Basel, a WPCA board member and vocal waste-to-energy critic, said he felt the AECOM report had many holes in it.

“When we went through it, it had many, many instances where AECOM said there’s information missing on this, information is missing on that,” Basel said.

“I said, ‘How could you state that the project is technically feasible if all this information is missing?’ ”

WPCA Executive Director Jeanette Brown said the reports were encouraging.

AECOM is very positive that the project is technically feasible,” Brown said. “That gives me a lot of confidence if a big company like AECOM is promoting gasification to their clients as a viable technology.”

Brown said grant funding and changes, such as skipping the project’s first phase, could make it more economically palatable. HDR management consultant David Traeger said the estimated $2.5 million gain is not enough to justify the investment on a financial basis, especially as operating costs and other risk factors could rise. However, gasification could provide valuable noneconomic benefits, he said.

“Any environmental project is probably going to cost money, so you need to look at the sustainability over the long haul too,” Traeger said. “There’s more than one aspect to evaluating feasibility than just financials.”

HDR Vice President Kurt Emmerich said state and federal air-pollution regulations will almost certainly become more restrictive in coming years, meaning that creating a sustainable treatment plant that can reuse waste rather than truck it to an incinerator is likely to become an asset. In that respect, Brown, who has spearheaded the project, is moving in the right direction, Emmerich said.

“Jeanette is leading you into something that is scary, and there are some uncharted waters, but she’s leading you where it’s going to be in the future,” Emmerich told the WPCA board.

Yet Cove resident Marikay Mead Wilson said she was still skeptical after seeing the presentation.

“It sounds like there are many unknowns, a lot of questions, and it sounds kind of half baked,” Mead Wilson said. “We can’t be the guinea pigs. We can’t afford to do this wrong.”

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