Edmonds leads nation with environmentally friendly gasification system for wastewater treatment

  October 23, 2023

Origami is already complicated, but what if instead of 4-inch-square pieces of paper, you were folding multi-ton metal tubes through a 12- by 12-foot hole, then building 26 feet below ground?

That’s basically what happened in Edmonds after the Edmonds City Council three years ago approved funding for the city’s new carbon recovery project. The project was designed to replace Edmonds’ aging incinerator, which disposed of sludge from the city’s wastewater treatment plant.

The project is now operating almost a year after it was originally scheduled to go online. Part of the delay was due to the challenge of installing the new system into the small wastewater treatment plant, located on a 3.94-acre piece of land in downtown Edmonds, next to the ferry terminal holding lanes. Approximately a quarter of this space is across 2nd Avenue South and there are multiple buildings in addition. The building that houses the plant is only 53 feet by 39 feet by 39 feet.

The goal of wastewater treatment is to remove as much of the suspended solids as possible – these are known as sludge or biosolids – before the remaining water, called effluent, is discharged to the environment. In Edmonds’ case, that effluent ends up in Puget Sound.

Dedicated in 1991, the Edmonds wastewater treatment plant has served Edmonds for more than 30 years. It also treats and disposes of sewage from nearby partner jurisdictions including the City of Mountlake Terrace, the Olympic View Water and Sewer District, and the Ronald Sewer District. But the sludge incinerator became increasingly expensive to operate and maintain.

The new treatment system went online in mid-September, and so far has processed over 100 tons of sludge, according to Dave Mooney, president and chief technology officer of Ecoremedy, the company that pioneered the carbon recovery system known as fluid lift gasification. Testing is still in progress and for now, Ecoremedy staff are running all the systems.

As soon as the new process reaches 24-hour capacity, training for the plant’s local operators will begin and they will take over the operations. This is expected to happen in October.

Ecoremedy’s patented process replaces traditional incineration with gasification. Through this system, a range of wastes — including components like PFAS that traditional incineration cannot break down — are subjected to high temperatures in the absence of oxygen. The extreme heat breaks the chemical bonds, a process known as lysis. Since oxygen is not present, nothing burns, so no CO2 is produced.

Gasification even produces a product that Ecoremedy has termed “FlexChar,” which can be used in a variety of practical applications. Typical sludge treatment using incinerators produces ash, which goes straight to the landfill.


Edmonds leads the way
The entire system that has been installed in the Edmonds facility is so unique that it just received a U.S. patent and has patents pending in 34 other countries, Mooney said.

Edmonds will join only three other locations in the U.S. and only a few in the world to use this process, according to a paper published by Wiley Water Environment Research titled Pyrolysis and gasification at water resource recovery facilities: Status of the industry.

Read the entire article by Keelin Everly-Lang on MYEdmondsNews.com