On May 24, the Cottage Grove Waste Treatment Plant had a violation of the coliform allowable limits in our DEQ NPDES operating permit for treated effluent that is used in our reuse program. This, according to Cottage Grove City Manager Richard Meyers.
"The permit allows for 23 micro-organisms per 100 mls and our test showed that we had 30 micro-organisms violating the allowable limit by 7 organisms. Wastewater staff has worked with the DEQ to improve our testing procedures to insure our treated effluent meets the permit requirements. The test for coliform requires a 24 hour incubation period to determine the results. Consequently the results of the test aren't know until after the effluent has left the plant," Meyers wrote to residents.
The violation marks the second violation in three years which warrants formal action on the part of the DEQ which may include a financial penalty.
"The current effluent reuse expansion project will help the plant meet the permit requirements. The expansion will create a large on site storage pond that will aid in ensuring the effluent meets the permit requirement before being pumped off site for irrigation use," Meyers said.
He told The Sentinel that the water is sampled but before results are in, the water is gone. A solution to that may be adding additional storage space--an issue that may come before the city council in the coming months.
Meyers noted that the water treatment plant tests Row River water once a month and its levels ranged from 276 micro-organisms per 100 milliliters 2,420 per 100 milliliters over the course of three months.