A new domestic wastewater treatment agreement between the city of Wahpeton and Minn-Dak Farmers Cooperative might be coming soon.
The current agreement, approved in 1997, allowed Minn-Dak to use Wahpeton’s sanitary sewer system for the treatment and ultimate disposal of its domestic sewage. The cooperative’s sewage flows to Wastewater Pond No. 1, members of the Wahpeton Public Works and Safety Committee were reminded during a Tuesday, Jan. 14 meeting.
Wahpeton has recently been examining the chemistry of wastewater generated by local industries. Biochemical oxygen demand (BOD) concentration is among the components being measured. BOD is measured as how much dissolved oxygen is needed in an amount of water so microorganisms can decompose the organic matter in the water.
Readings taken from Minn-Dak’s domestic wastewater streams in mid-2019 showed a BOD level between 600-650, Public Works Director Dennis Miranowski said. The latest reading, taken on Jan. 2, showed a BOD level of 265. An ideal BOD level is at or near 250.
“We discovered (in 2019) that there was some of what I’d call ‘cross connections,’” Miranowski said. “Minn-Dak began working on that, investing $40,000 in improvements.”
Ron Johnson, a project engineer with Minn-Dak, said the high BOD concentrations were traced back to the Wahpeton facility’s on-site testing lab. What happened is raw sugar was introduced into the wastewater system when test samples were disposed of.
“All the lab area has been separated off the city system now and we’re pretty confident,” Johnson said.
Test sample history reviewed by Kyle Rogahn, Wahpeton engineering project manager, showed high BOD and ammonia level readings for test wells for both Minn-Dak and the Minn-Dak Yeast Company. The plumbing, according to information shared, has been updated to segregate the sinks used for test sample disposal from the domestic sewage.
“We thank you. You’ve made great strides,” Miranowski said.
Minn-Dak’s history and future will be discussed Thursday, Jan. 16 at Wahpeton City Hall. The cooperative is on the agenda of the Mayor’s Ad Hoc Committee on Environmental Odors, which began receiving reports from area industries in December.
In late 2019, Minn-Dak said it was working to find a source point for strong odors. An exact source of any objectionable odor had not been determined as of December.
“I do thank for your diligence and for making adjustments after the high readings were identified,” 4th Ward Councilman Don Bajumpaa said. “To me, that shows you’re working in good faith to do what you can with what you have.”
Councilwoman at-large Tiana Bohn, the committee chair, suggested drafting a domestic wastewater agreement which would include acceptable discharge levels and sampling requirements. The new Minn-Dak agreement would be modeled after one negotiated with Cargill in 2019.
It is unknown when the new agreement for Minn-Dak will be ready for the Wahpeton City Council. Daily News will continue to follow this story.
“We’re on it,” Miranowski said.
Wahpeton City Hall will be closed Monday, Jan. 20 in observance of Martin Luther King Day.