The City of Grinnell reported an approximate bypass of 204,000 gallons of partially treated wastewater at their wastewater treatment plant at 3976 20th St, one mile southwest of Grinnell. A portion of the bypass reached Sugar Creek.
Since January 24, the City of Grinnell has been diverting all of the wastewater treatment plant influent flow to its equalization basins so the center column of the trickling filter could be replaced. Just after midnight, January 27, the first equalization basin began overflowing into the second equalization basin. A value was not completely closed, and allowed flow to be directed to the treatment plant instead of storing it in the equalization basins. At 7 a.m. staff discovered the flow entering the treatment plant, flowing through a portion of the treatment units and discharging to Sugar Creek.
By 8 a.m. the discharge was stopped by placing a plug in the line from the equalization basin.
There was no apparent impact to Sugar Creek.
The center column replacement project is expected to be completed today.
For more information contact Tom Atkinson at Tom.Atkinson@dnr.iowa.gov or by cell at 515-577-9296