A malfunctioning, telescoping valve on a solid waste holding tank at the Atlantic Waste Water Treatment Plant Sunday night, resulting in about 10,000 gallons of treated, activated sludge solids reaching the East Nishnabotna River. Water Pollution Control Department Superintendent Tim Snyder said the problem was discovered by treatment plant staff when they arrived at around 7-a.m. today (Monday).

Snyder said the malfunction, which happened sometime between 8-and 9-pm Sunday, allowed the holding tank to drop three feet over the course of an hour. He says while a large portion was returned to the start of the plant, the plant drain pumps were overwhelmed by the sudden large flow. The valve is normally only lowered in 4-6 inch increments.

Excess solids then escaped the system by raising a manhole lid and going onto the ground ultimately reaching the river through the storm water drain. Plant cleaning equipment is cleaning up the solids captured on-site. Snyder says steps will be taken to add a secondary restraint on the valve and the manhole ring and lid will be changed to a bolt down configuration.

The Iowa Department of Natural Resources has been notified, and they will notify those potentially affected downstream.