WATERLOO — The city has developed plans to spend more than $100 million renovating its sewage treatment plant over the next two decades.
Waterloo City Council members voted unanimously Monday to submit a facility plan to the Iowa Department of Natural Resources, which includes more than $56 million of work over the next five years.
Waste Management Services Director Steve Hoambrecker said the document must be on file for the city to get Iowa DNR approval for the improvements and to qualify for low-interest financing through a state revolving loan fund.
The plan was developed by Strand Associates Inc. of Madison, Wis., which noted renovating the existing plant on Easton Avenue is much less costly than building a new plant to meet the city’s needs and environmental regulations.
“If you had to build a new plant to do what this one can do, you’re probably talking close to $1 billion of investment,” said Strand’s Randy Wirtz. “Here we’re talking about $100 million.”
The plant improvements are necessary to cut the amount of nitrogen and phosphorous the plant releases into the Cedar River, replace aging equipment and make the plant more efficient.
“There are a lot of inefficiencies in the way the plant is laid out now,” Wirtz said. “The plant has a lot of capacity, but you can only use about half of it.”
The plant, largely constructed in the late 1990s, was designed essentially as two plants sitting next to each other. It will take a large investment to combine the two plants to operate as one, but the improvement more than doubles the amount of waste the city can treat.
A portion of the $56.3 million in estimated work over the next five years is already well into design. Another $29.3 million, mostly for equipment replacement, is projected for 2023 to 2028.
“It’s all about 20 years old now or more,” Wirtz said. “It’s going to take a lot of money to replace the equipment.”
Another $15.3 million in long-term improvements to increase the plant’s hydraulic capacity many not be necessary if flows to the plant can be reduced.
The city has been investing millions of dollars on projects to reduce storm water inflow into the sanitary sewer lines, which include lining pipes and home footing drain removal programs.
While the city is under a court order with the U.S. Justice Department to complete those improvements to reduce raw sewage overflows, the work has an added benefit of reducing flows to the treatment plant itself.
Hoambrecker said the approved facilities plan does not include a proposal under study to capture, scrub and sell biogas generated by the sewage pre-treatment lagoon near Tyson Fresh Meats. Engineers are evaluating the viability of that project now, which could be added in the future.