Edgar pleased with plant redesign
Can a self-described “cheapskate” successfully redesign the Edgar wastewater treatment plant? The answer is yes.
The Edgar Village Board on Monday gave Gary Strand, Cooper Engineering, high marks after presenting his revised facility plan to retrofi t the existing village sewer plant for $4 million.
Board members said they were happy that Strand, who would reuse the plant’s existing Rotating Biological Contactor (RBC) chambers as anaerobic digester tanks, will be able to deliver a functioning sewer plant for approximately half the cost of scrapping the current plant and building a new one.
The praise followed Strand detailing his sewage treatment proposal as part of a public hearing.
Strand said the Edgar plant, which dates back to the 1930’s, was in good shape, especially old concrete that continues to harden when kept under water.
“Everything is structurally sound down there,” he said.
Strand said the village could no longer use RBC technology to take nutrients out of the village’s waste stream, but it could re-use the concrete chambers they sit in with some minor modifications for anaerobic digestion.
Strand added the village will likely be able to sell the scrapped RBC parts to other municipalities.
The engineer said his plan was to deliver a reconfigured sewage treatment plant without major changes to the plant’s current footprint.
One footprint change, he said, would be construction of a second, 50-foot diameter final clarifier tank.
Strand said the village should use a Multi-Discharger Variance (MDV) to handle phosphorus limits in its next DNR sewer permit. This variance will involve buying phosphorus credits from the Marathon County Conservation, Planning and Zoning Department.
The engineer thought the village could, in time, wean itself off this program, restricting phosphorus effluent to 0.3 parts per million, which would be a permanent solution.
“You won’t have any problem at all meeting the 0.3,” he said.
Strand said replacing the RBCs with anaerobic digestion would likely fix a problem where the plant has objectionable odors intermittently on warm summer days.
The engineer said the smell likely comes from RBC bacteria turning septic.
“Activated sludge doesn’t stink unless you don’t add enough oxygen,” he said.
Strand and board members discussed at length whether to use the DNR or USDA for a wastewater treatment plant loan.
The DNR offers a 20-year loan with the possibility of a 15 percent grant. USDA, on the other hand, will provide up to a 45 percent grant but requires a 40-year loan. Interest on the USDA loan is double that of DNR financing, but the federal agency will let villages merge old debt with a new loan.
Strand said village board members shouldn’t think they will have an “old” sewage treatment plant once the project is complete.
“You are taking what is good at the plant and revising it,” he said. “It will be a nice, new plant, but at half the price or less.”