McCordsville officials received notice recently that its wastewater treatment plant sustained a failure.
An unknown substance has killed off most of the microbiology organisms that are needed for the treatment process.
The Indiana Department of Environmental Management was notified on May 26 when the first incident occurred and has been aiding McCordsville with the emergency.
Treating 450,000 gallons per day if wastewater, the facility uses various treatment methods including screening, settling tanks and biological treatment. The biological treatment breaks down the waste and consumes the organic nutrients and makes the other treatment methods more effective. The discharge to the facility that killed the microorganisms is unknown, and samples have been sent off to determine a cause.
McCordsville was also notified by the City of Lawrence that discharge had entered a ditch within Lawrence, causing water in the ditch to appear black.