Edmonds approves contract for gasifier operations at sewage plant

Published 1:30 am Thursday, April 9, 2026

EVERETT — After three years of trial and error, the city of Edmonds may begin consistently operating the gasification system at its wastewater treatment plant this month.

On Tuesday, the Edmonds City Council approved a $415,000 contract with Jacobs Engineering, an engineering consultant, to assist the city with operating the technology. The city’s wastewater utility fund will fund the contract.

The project has been in the works since 2018, when the city was considering greener options to replace the sewage plant’s incinerator, according to Tuesday’s council agenda memo. The state enterprise services department contracted with Ameresco, an energy solutions provider, to develop a proposal for the project. The technology, provided by Ecoremedy, uses gasification to turn human waste into dried solids.

A 2025 Hazen study found the technology destroys Per- and polyfluoroalkyl substances, or PFAS, in biosolids. Known as “forever chemicals” because they take centuries to break down, PFAS can cause serious health effects, including certain cancers, liver damage, and reproductive and developmental issues. Edmonds was the first city in the country to implement the new technology.

The council approved the project in 2020. From 2020 to 2023, the construction cost grew from $26 million to $31 million, according to the memo.

The city initially attempted to launch the technology in April 2023. Since then, the system has run into several issues, including a defective end-product conveyance system, conveyance systems and the dryer clogging with wastewater solids, equipment breakage, smoke plumes, and smoldering of wastewater solids during processing, according to the memo.

Since 2023, the city has been hauling solids from the plant to a landfill in eastern Oregon.

In 2024, the state enterprise services department issued a list to Ameresco of items it needed to finish before the project could be considered complete.

In November 2024, the City Council authorized an $894,000 agreement with Ecoremedy to operate and maintain the system for six months. Ecoremedy began operations in April 2025, but was “unable to achieve consistent operations,” the memo read. The enterprise services department, Ameresco and Ecoremedy developed a corrective action plan, and the organizations returned to the plant in January to perform the corrective work.

Only one item — a screw replacement — remains in the corrective action plan, city spokesperson Natasha Ryan said in an email Thursday.

Starting April 27, Jacobs Engineering will help the city operate the gasification system through 2027, per the agreement. In 2028, the city will begin using the gasifier unassisted, Ryan said. Jacobs Engineering has been working with the city on the technology since at least 2024. In February, the city entered into a $500,000 on-call contract with Jacobs Engineering for other treatment plant operations.

Starting Monday, EcoRemedy will conduct a five-day, 24-hour demonstration of the system, which Jacobs Engineering staff will observe.

Ryan said the city is hopeful the gasification system will work as intended moving forward.

Jenna Peterson: 425-339-3486; jenna.peterson@heraldnet.com; X: @jennarpetersonn.