Pittsfield council eyes solar sludge plan

Posted Nov. 18, 2008, at 11:29 p.m.
Last modified March 20, 2011, at 6:03 a.m.

PITTSFIELD, Maine — The town of Pittsfield may become the pilot site in the state for a unique sludge removal project, a solar drying system that could get rid of decades’ worth of sludge from the town’s wastewater treatment plant with minimal cost.

Kirk Ball of Acheron Engineering explained that each of the two lagoons at the plant are 35 acres — twice the size of the town’s Mill Pond — and likely the largest lagoons in the state. The system is 30 years old and sludge was to have been removed every 10 to 15 years. It never happened.

Now, faced with decreased efficiency that could result in hefty environmental fines, the town is seeking solutions. At his presentation to the council Tuesday night, Ball outlined treatment and disposal options that ranged from just under $1 million up to $10 million.

The report states that because the sludge has never been removed, the system is operating at about 75 percent efficiency.

Ball recommended a solar drying system, which is unique to New England and is being looked at skeptically by the Maine Department of Environmental Protection. It would involve building a drying area over several acres, contained by a natural berm. The sun would dry out the sludge to a lighter-weight product that then can be disposed of.

“This is an avenue that is out of the box,” Ball said, “but we think it can work.” Although the solar system would be environmentally sound and less costly, weather is a big factor in its success. The dryer the final product can be, he explained, the less it weighs and the less the disposal costs.

“Size is what the difficulty is,” Ball said. “This is a tough one.”

Acheron’s report outlines several options for disposal, including transportation costs, composting, landfill and land application. Acheron does not recommend the land application option. Aside from being very controversial, land spreading would require 4,000 acres.

Ball said disposal options for the dewatered final product all run about $50 a ton, whether at a landfill or composted. The report does recommend that Pittsfield discuss the option of disposal with Hartland. Hartland’s municipal landfill is licensed to accept sludge from its wastewater treatment plant and could obtain a one-time-only DEP permit to accept Pittsfield’s sludge.

This would cut Pittsfield’s transportation and disposal costs, Ball said, but also would provide added revenue to Hartland.

Ball suggested meeting with the DEP to come up with a pilot project for the summer of 2009.

“This would give us sound science so we could proceed with the full project,” he said. The pilot project would consist of constructing a model lagoon about two times the size of a home swimming pool. The project would cost $15,000. “But if we can convince the DEP to go with the solar drying option, the cost savings would be enormous,” Ball said.

In other business, the council accepted the resignation of Councilor Michael Cianchette due to a change in his work obligations, and set a special election for Wednesday, Jan. 14, 2009, to fill the at-large position.

The council also congratulated the Pittsfield First Universalist Church for its recent coordination of a KeepME Warm project that involved more than 80 volunteers and winterized 25 local homes.

SEE COMMENTS →

ADVERTISEMENT | Grow your business
ADVERTISEMENT | Grow your business

Similar Articles

More in Mid-Maine