EagleHerald Staff Writer
MARINETTE—The target date for starting up the new system that will dry and compress the City of Marinette’s biosolids will be delayed to January, according to an update last week from Water & Wastewater Operations Manager Warren Howard.
In June 2019, the City of Marinette notified the Wisconsin Department of Natural Resources (DNR) of elevated per- and polyfluoroalkyl substance (PFAS) levels in its wastewater. The DNR later identified the historic discharge of firefighting foams from Tyco Fire Controls (Tyco), a subsidiary of Johnson Controls, Inc. (JCI), into the city’s sanitary sewer system as the main cause of the contamination.
After discovering these elevated PFAS levels, the City of Marinette decided to install a system to dry and compress the biosolids then ship them to Columbia Ridge Landfill in Oregon. Tyco/JCI gave the city $1.3 million to purchase the equipment.
The system consists of new Seepex progressive cavity sludge feed pumps, a PWTech Volute dewatering press and a Sunstate Environmental Shincci USA dehumidifier. The sludge feed pumps are conduits for the wastewater. These conduits feed the dewatering press, which removes some of the liquid from the sludge before it is further compressed and dried by the Shincci dehumidifier. After the biosolids are processed through the system, they are lighter and therefore less expensive to ship out to Oregon.
This project began over a year ago. The equipment was on order in October 2020 and expected to arrive within a few months. Because of supply chain delays, however, this date was pushed back to April. At the March 2021 Water & Wastewater Utilities Commission meeting, Howard said the new target date for the system to be up and running was mid-May.
But the equipment didn’t arrive until about two months ago. It had been damaged, furthermore, in transit from China, making it unusable. Howard said last week that he expects replacement equipment to arrive in January.
Currently, wastewater sludge is being stored in a large tank at the Wastewater Treatment Plant. Howard said it will take about another eight to 10 months from now before the storage tank is full. If all goes well and the system starts up in January, sludge will be siphoned directly into the dehumidifying system for processing. Simultaneously, sludge from the storage tank will gradually be fed into the system.
Once the biosolids are dried, they will be loaded into a dumpster and transported to a warehouse in Menominee. From Menominee, the biosolids will be shipped out every month by railcar to the landfill in Oregon. The transit will take about a month round-trip.
Howard said the Wastewater Commission is budgeting $120,000 for 2022 to handle the disposal of these biosolids. This amount could fluctuate, however; Howard said it’s uncertain how much the process will cost until it’s underway. The city, for example, will pay a flat fee for the railcars that will transport the biosolids to Oregon. The more material that can fit into each railcar, consequently, the less the city will have to pay, and vice versa.
Previously, semi trucks would haul away the biosolids directly from the Wastewater Treatment Plant and take them throughout Marinette County where they were spread on over 60 fields. The DNR launched an investigation in 2019—shortly after the city reported elevated levels of PFAS in its wastewater—to assess the impact of the contaminated biosolids in the areas where they were spread.