After seven years of planning and construction, the Detroit Lakes Water Reclamation Facility opened its doors to the public for a day of guided tours.
The public tours on May 18 guided guests along the wastewater treatment process with attendees able to ask questions about the facility along the way.
"I told the (Minnesota Pollution Control Agency) that I don't want to be in a situation where we'll replace something and then three years down the road they go with a different limit, or another regulation comes through and we have to abandon what we just built and start over," said Vernell Roberts, general manager for Detroit Lakes Public Utilities.
Roberts said the project took seven years from start to finish because designing for future regulations that didn't exist at the time concerning phosphorus was difficult.
"We've had two governors come and visit with us about this project, and when Gov. Dayton was still the governor, we had a meeting at city hall," Roberts said. "I was telling the governor, 'you know, this is going to be an expensive project for a community and it's going to put a lot of burden on our rate payers, and I don't want to be that guy that spends $34 million and gets it wrong.' So, I wanted to make sure we did it right, and I think we did it right."
The city's new wastewater treatment plant was designed to limit the amount of phosphorus and nitrogen in the facility's outflow to Lake St. Clair. The plant decreased the amount of phosphorus in their outflow from 1 mg per liter to 0.066 mg per liter. Additionally, the facility also decreased the amount of nitrogen in their wastewater exhaust, which effect algae growth, by 75%, according to public tour documents.
The technology making these improvements possible is a series of hollow fiber membranes which filters the wastewater with 0.04 micron openings called a membrane bioreactor, or MBR. The openings in the fibers are smaller than viruses, like coronavirus, which are typically sized at 0.1 micron. The wastewater is pumped through the filtration membranes and leave the microorganisms and bound phosphorus behind.
"Wastewater treatment plants aren't really sexy," said Roberts. "You build another new facility that has a lot of glitz and glamour … and everybody comes here and says, 'oh, that stinky place,' but there is a lot that goes on here to protect the waters of our community in northwest Minnesota and the lakes down stream from us, and we are pretty proud of what we've done even though it may not be sexy. It's a pretty nice facility and suits us well."
Once inside the facility, the pipes are color coded to give the seven staff members who monitor the facility an easy time identifying what type of water, or waste, is flowing through the pipes, similar to the pipe color coding on U.S. Navy ships.
The new facility cost more than $33 million, but the city was able to secure $17 million in grants through the Point Source Implementation grant program, the Clean Water State Revolving Fund and Water Infrastructure Fund Grant to help pay for the project.
The ground breaking for the project happened in April 2018 with construction of the new additions finishing in spring 2020. However, the final performance testing couldn't be completed until April 2021 because the pandemic caused a border closure with Canada and the facility couldn't host the Canadian test administrators. Now, with the testing complete and the plant operational, Roberts said he believes the treatment plant will be around for decades to come.
Through its seven-stage wastewater treatment process, the facility has the ability to handle 2.21 million gallons of wastewater per day on average, however the city of Detroit Lakes only produces about 1.2 million gallons of wastewater per day, which leaves some room for growth in the system, Roberts said.
"We had to find that sweet spot between anticipated growth in 2030 and 2040 versus really going overkill and having way too much, and spending way too much money for growth that may or may not happen," he said.
The facility was designed to for operation through 2038 and could handle a population of 15,584, which is nearly 75% more than the current population of Detroit Lakes.
In terms of solid mass, the new wastewater plant generates an average of 3,442 pounds per day of organic, and inorganic, particles that cannot be broken down by the facility.