Washington approves partial payment for belt press rebuild; staff warns of PFAS risk to sludge disposal

The City of Washington Public Works Department voted to approve a partial payment of $136,757 to Alfa Laval for equipment delivered for a rebuilt belt press at the wastewater treatment plant.

Public works staff said the city chose to rebuild the facility's original belt press rather than buy a new unit because rebuilding was far less expensive. “It was either buy a new one or rebuild it. The new one ran around $600,000; to rebuild it here was under $300,000,” Kevin, a public works staff member, said. He added the rebuild will leave the original frame but replace nearly all other components.

The belt press, which squeezes water from sludge after polymers are added to create a cake suitable for land application, is necessary for the plant’s sludge disposal. “If we don’t have the belt press, we have nothing else to do with our sludge,” Kevin said, explaining that without it the city would be unable to continue spreading the material on agricultural fields used by the city.

Kevin told the panel staff had inspected the equipment on site and that additional parts were still expected. He requested payment for the equipment that has arrived; the amount was budgeted and carried over from last year’s capital plan. A motion to approve payment was made and seconded; the record shows a voice vote in favor and the payment will be sent on to the City Council.

Staff also warned the commission about an emerging regulatory and treatment concern: PFAS, the class of so-called “forever chemicals” used in waterproofing and sealants. Kevin said the treatment plant’s sludge contains PFAS and that regional regulators — he named the U.S. Environmental Protection Agency and the state Department of Natural Resources — have not finalized regulatory decisions, but that those decisions could require the city to change how it disposes of sludge.

“We think it’s coming from the landfill,” Kevin said, noting that leachate from both the current and older landfills is processed at the plant. He said the city began pretesting sewage for PFAS ahead of regulatory requirements and will do more in-depth testing to try to locate sources. If PFAS appears in sludge sent to farms, staff said, it could force the city to stop broadcasting biosolids and pursue high-cost options such as incineration combined with air filtration.

Kevin estimated regulatory-driven needs to address PFAS could emerge in roughly three to five years but said the timing is uncertain. He described the chemical as “terrible” and cautioned that treatment or disposal options remain under development by researchers.

The commission meeting record shows the payment request was budgeted, carried forward from the prior year, and approved at the meeting to be forwarded to council.