Fecal Coliform Bacteria Issues at Empire Wastewater Treatment Plant, March 2

Summary: Over the last week, the wastewater treatment plant in Empire has experienced higher than normal fecal coliform bacteria counts. The city’s wastewater operations and maintenance (O&M) contractor has evaluated the wastewater data, but the root cause has not been determined. While the plant is not subject to daily fecal coliform limits, it is subject to monthly requirements. Unfortunately, due to this event, for the month of February the monthly Fecal Coliform limits will not be met. Detailed Report: Over the last week, the wastewater treatment plant in Empire has experienced higher than normal fecal coliform bacteria counts. Fecal coliform are used as indicator organisms to test the effectiveness of effluent disinfection in a wastewater treatment plant. While these organisms are generally harmless to us, they do live under the same conditions that human pathogens live. Since we cannot test for every pathogen in the effluent, we test for easily detectable indicator organisms. The assumption is that if we kill the indicator organisms then we most likely kill the pathogens during effluent disinfection. The plant has to meet effluent water quality limits that are identified in a permit that is issued to the city by the Oregon Department of Environmental Quality (DEQ). While the plant is not subject to daily fecal coliform limits, it is subject to monthly requirements. Unfortunately, due to this event for the month of February, the fecal coliform limits will not be met. The cause of the higher than normal fecal coliform count is not known at this time. Until the contract operator can determine the root cause for the fecal coliform permit exceedance, the city has increased the dosage of the ultra violet (UV) disinfection system to the maximum setting. This will help protect water quality, and this extra precaution will remain in place until acceptable fecal coliform counts are observed. The city reported this issue to the Department of Environmental Quality and Oregon Emergency Response System (OERS). Any questions can be directed to the City of Coos Bay Public Works Department at (541) 269-8918.