July 19, 2024
Crushing Juneau’s treated sewage waste before shipping it could save almost M a year
Senior wastewater operator Ryan Hosman shows what microbes that consume sewage look like after they’ve been partially dewatered through a belt filter press at the Mendenhall Wastewater Treatment Plant in Juneau on March 23, 2021. They go through a dryer to further reduce their volume and become biosolids. (Photo by Jeremy Hsieh/KTOO)

After sewage is treated in Juneau, there’s a byproduct left behind known as “biosolids.” And the City and Borough of Juneau pays about $1.4 million a year to ship containers full of it to a landfill in Oregon. City officials say that buying new equipment to crush these cakey biosolids down before shipping them could slash that bill by two-thirds.

The city pays for shipping per container, and that cost has been going up, according to Denise Koch, the city’s deputy director of Engineering and Public Works.

“We really need to – you know, I use the technical term, ‘pack it in,’” Koch told the Juneau Assembly’s Public Works and Facilities Committee on Monday. “We really want to get more volume into each conex because it’s so expensive to ship those conexes.”

Juneau Assembly member Wade Bryson put it like this: “We’re shipping a lot of air down south.”

Koch’s department is asking the Juneau Assembly to spend $2.5 million of wastewater user fees to buy a crusher. She estimates it would pay for itself in about two and a half years.

The Committee gave the concept the thumbs up. The full Assembly must hold a public hearing and vote on an ordinance to authorize the spending.

The city has spent tens of millions of dollars over the last 12 years disposing of its treated sewage. It used to burn what was leftover, but its sewage sludge incinerator failed in 2010.

At first, the city contracted with the local landfill operator to dispose of the sludge. But there was too much – hundreds of tons a month – and it made the landfill’s nuisance odor problems worse. The landfill didn’t want to renew its contract.

So then the city started shipping the sludge down south for disposal. But leakage and odor problems caused problems in the barging business. So the city bought 45 watertight shipping containers it used in rotation to keep the sludge moving. In 2015, it cost about $2 million to ship the sludge.

In 2016, the city committed about $16 million to build a dryer facility, which removes water from the sewage sludge and turns it into biosolids. It went online in 2019. City officials thought it would also treat the sludge enough to meet environmental standards for applying it to land, eliminating the need to ship it out of town.

But as the dryer was being brought online, public health experts and environmental regulators were researching and working on regulating various “forever chemicals” — PFAS, PFOS and PFOA. These chemicals are in Juneau’s biosolids at levels that prohibit land application. So, Juneau still ships its processed sewage out of town for disposal in a landfill.

Ironically, one known source of these chemicals in the sewage system is the wastewater that leaches down through Juneau’s landfill. Some of the water that leaches out is collected and piped into the sewage system for treatment.

Crushing Juneau’s treated sewage waste before shipping it could save almost $1M a year