Strict new regulations issued by the Iowa Department of Natural Resources have forced the City of Clarinda to proceed with extensive renovations to the wastewater treatment facility despite the financial toll such a project would take on residents.
Steven Troyer of Fox Engineering met with the Clarinda City Council on Nov. 15 to review the condition of the plant and the new regulations. In order to comply, Troyer proposed an $11.7 million upgrade to the wastewater plant that was approved by the council.
Clarinda City Manager Gary McClarnon said a 20-year loan to finance the project would increase sewer bills by $30 a month. A 30-year loan would increase bills $25 per month, but result in a higher total cost to pay off the loan due to a higher interest rate.
Increases would be implemented once bonds are issued to finance the project. Actual construction is estimated to begin in 2019 and take two years.
“It’s going to put a real burden, I feel, on some of our citizens,” Clarinda Mayor Gordon Kokenge said. “I guess what I’m doing is questioning why Clarinda? How about all the other communities in the state of Iowa? And where is the funding going to come from? ... If the state of Iowa is demanding that, then they should help foot the bill.”
John Veach of the Iowa Rural Water Association said the regulations came into effect in 2006.
“Several towns have already done this exact thing. The only reason you haven’t had to do it is your permit has been delayed about five years,” Veach told the council. “Nobody wants to pay more, obviously, but even with an extra $30 on our bills, we’re still far more economical than a lot of towns in Iowa.”
Built in 1954, the facility is classified as a trickling filter plant. A flow equalization basin was constructed in 1987, and the last major upgrade was in 1996.
The plant has a maximum flow rate of 3.43 million gallons per day for any given 24-hour period. However, the plant was only designed with the hydraulic capacity to treat 1.78 million gallons per day.
As a result, Clarinda had 116 days between January 2010 and November 2016 where a bypass was recorded due to the low hydraulic capacity of the plant. Troyer said on those days more flow came to the plant than it could treat, so wastewater had to bypass the plant and be discharged into the stream untreated.
“We propose to increase that capacity to about 3.2 million gallons a day. That is almost doubling the hydraulic capacity of the plant to address those bypass situations,” Troyer said.
The hydraulic capacity was one of three primary areas Fox Engineering identified deficiencies with the plant. The others were age and permit compliance.
Since most of the plant is more than 60-years-old, Troyer said natural deterioration has occurred. He said a lot of the equipment is past its useful life.
“Our maintenance costs are going up every year,” McClarnon said.
Veach and Harry Ridnour of PeopleService agreed the plant has exceeded its life expectancy.
“PeopleService has done a lot of maintenance to keep it going as long as we have, and we’re just at the point where you can’t repair something that is way beyond repair,” Ridnour said. “There is nothing you can do to meet the new requirements that have come out with what we have.”
Troyer agreed there are code compliance issues with the plant.
“As you might expect, over the years, the codes have changed and gotten more stringent,” he said. “There are also some safety issues that are kind of related to the code compliance issues.”
Troyer said the latest permit from the Iowa DNR requires Clarinda to implement disinfection of its wastewater. However, since the plant does not have the necessary facilities to meet this requirement, he said they would have to be added and be operational by July 2019.
Troyer said Clarinda was required to provide disinfection because of a use attainability analysis conducted by the DNR that determined the West Nodaway River could be used for recreation.
“I question how they came up with that. Knowing the river, as most of the residents do around here, I don’t believe anybody really wants to swim in that river,” Kokenge said.
The other aspect of permit compliance is the nutrient reduction strategy, Troyer said.
“The goal of the nutrient reduction strategy for municipalities is for those major facilities, which Clarinda is one, to reduce the total nitrogen and total phosphorous that is being discharged,” Troyer said. “Your current facility doesn’t have the capability of removing nitrogen and phosphorous, so to comply with the nutrient reduction strategy there would need to be some additional facilities added.”
Given these issues, Troyer said Fox Engineering considered various options for updating the existing treatment plan. He said expanding and refurbishing the existing facility to meet all the requirements except the nutrient reduction strategy would cost $10,518,000. To also meet the nutrient reduction strategy, the cost of refurbishing the existing plant would exceed $14 million.
Therefore, Troyer suggested Clarinda switch to a sequence batch reactor facility at a cost of $11,696,000. Changing to this process would allow the city to comply with all the permit requirements including the nutrient reduction strategy.
“I think that’s the best way to go, personally,” council member Gary Alger said. “To me, redoing the old one just doesn’t make sense.”
Troyer projected construction of the necessary improvements to the plant could start in 2019 and be completed in 2021. As a result, Troyer said Clarinda would need to request an extension on the implementation of a wastewater disinfection process.
“There is also a statute in Iowa that would provide a 10-year moratorium,” Troyer said. “If you build these facilities, the DNR would not be able to crank down your discharge limits within that 10-year period,”