Officials outline $3.7M biosolids project and larger plant upgrade needs; bonding and ownership options debated

At an informational session, wastewater plant staff and legal counsel described a near-term $3.7 million project to reduce biosolids hauling costs and outlined longer-term treatment-plant upgrades that could total $15 million to $20 million within five to seven years.

Casey Rose, director of the wastewater plant, said the plant stopped selling composted biosolids after state regulators tightened requirements related to PFAS. ‘‘Because of the current concerns of PFAS, they decided that we are no longer allowed to compost our biosolids and sell it to the public,’’ Rose said. He told meeting participants that the change forced the plant to landfill all biosolids and raised annual disposal costs from about $40,000 to roughly $250,000.

To reduce hauling volume and long-term disposal costs, plant staff and engineer GEI have proposed replacing the existing belt press with a screw press and adding a dehydration step. Rose said the plant’s current solids ‘‘cake’’ is about 14–15% solids; a screw press would raise that to about 18–20%, and a dehydrator could raise solids to 70–90%. At 70% solids, Rose estimated the plant could reduce tonnage sent to the landfill by roughly 80%, saving on the order of…