Bellingham wants to turn waste into something useful. Here’s how much that could cost.

Sewer rates will increase in the coming years to pay for an estimated $196 million project to replace the aging incinerators at the Post Point wastewater treatment plant with a proposed process that fits the city’s Climate Protection Action Plan to reduce greenhouse gasses.

How much sewer bills will go up will be determined through a planned rate study. Construction could start in 2023 at the plant at 200 McKenzie Ave., and be completed in 2025.

The City Council still must give final approval to the proposed project although it has been guiding it along the way. Members received a project update on Monday.

The incinerators are from the 1970s, Public Works officials said.

“We have to do something. The existing incinerators have reached the end of their useful life,” Eric Johnston, assistant director for the Public Works Department, told The Bellingham Herald on Monday.

The incinerators are also expensive to repair, officials said.

“We’re spending a lot of money, time and resource in keeping these incinerators running, several hundred thousand dollars a year,” said Ted Carlson, the city’s Public Works director.

What Post Point does with your wastewater

So what does the Post Point plant do now with wastewater that comes to it from the city and the Lake Whatcom Water and Sewer District?

When people flush their toilets, take a shower, wash their clothes or put bits of food down a drain, all of that is carried along in miles of pipes to the treatment plant. There, the trash in it, such as wipes and tampons, are pulled out and discarded.

The water is treated before being released into Bellingham Bay, several hundred feet offshore.

Other solids left behind, such as human poop, are eaten by tiny biological organisms. When they die, they are put into the plant’s two incinerators, which run around the clock to turn 7,000 tons of biosolids into 900 pounds of ash that are then taken to Klickitat County’s Roosevelt Regional Landfill, one of the largest landfills in the United States.

“Biosolids are the nutrient-rich organic materials resulting from the treatment of domestic waste,” Johnston said.

So what’s the new proposal?

Instead of burning the biosolids, which releases emissions into the air, the city would switch to an anaerobic digestion process, “which, for lack of a better term, is just a really fancy way of composting the solids,” Johnston said.

It would then use the biogas, a combination of carbon dioxide and methane, created during the process to generate electricity in an engine or generator at Post Point. It also could be purified and used as a natural gas replacement, and sold to a natural gas utility or wholesaler, according to Public Works officials.

Then they could take the nutrient-rich biosolids and transform them into fertilizer or topsoil.

Not burning the solids would reduce the city of Bellingham’s overall carbon emissions by 30 percent, Public Works officials said.

“We’ve got aging infrastructure. It needs to be replaced. Whether we replace it with modern incinerators or we replace it with a digestion, the cost is going to be about the same. It’s a big number,” Carlson said.

Related stories from Bellingham Herald

Kie Relyea has been a reporter at The Bellingham Herald since 1997 and currently writes about social services and recreation in Whatcom County. She started her career in 1991 as a reporter and editor in Northern California.