Vermillion may have wastewater solution in September

SIOUX FALLS, S.D. (KELO) — The city of Vermillion could get a permanent solution for its flood-damaged wastewater treatment system by the end of September, the city’s utilities director Shane Griese said on Monday.

“Right now we are hoping to have all three force mains replaced by the end of September before frost,” Griese said. He said that may be a “lofty goal” but the city and the state of South Dakota are working well together to find a solution.

The flooding of June 21 and 22 damaged the three force mains in the city’s system. The first two were damaged and a third followed later. The city was forced to discharge raw wastewater into the Vermillion River at a rate of about 1.2 million gallons a day from June 27 through July 12, Griese said.

The city’s website said the plant handles about two million gallons a day on average and has a peak capacity of about four million gallons a day.

Residents were asked to curb water use to reduce the amount of the discharge.

Griese said the city tested the water upstream from the plant and downstream from the plant.

What was being discharged from the plant system was diluted by the high amounts of water in the river, Griese said. The discharge also went through what Griese described as a type of mechanical process where solid waste is broken down, he said. The public would not have seen solids in the river water, he said.

The permanent solution will likely include burying new force mains deeper around the river, Griese said. The city is considering going as far as 50 feet under the river bottom, he said.

The original first two mains were dredged in roughly three to five feet and allowed to settle, Griese said.

The third main was installed at a depth of 10 feet, according to Griese.

The mains did well until the historic flooding, Griese said. But, “we’d like to (install new) as deep as we can, so hopefully, this never happens again,” Griese said.

The flood damage required temporary repairs, but it also allowed city staff to do maintenance work at the plant.

“Those kinds of tasks are more difficult to do when the plant is in full operation,” Griese said.

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