The City of Coos Bay’s Wastewater Treatment Plant #1, located at 680 Ivy Avenue, experienced a high fecal coliform count today. Fecal coliform is 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 high fecal coliform is believed to be a result of not enough chlorine being delivered to the treated effluent for disinfection prior to discharging to the bay. The city’s contract operator noticed a reduction in flow and traced the problem to a blockage that restricted flow to the chlorine delivery pumps. The restriction was corrected, and chlorine flows resumed to normal levels but from 10am to noon, the plant’s effluent experienced high fecal coliform counts. Chlorine is a common chemical in processing wastewater and is utilized to disinfect the treated effluent. After chlorine disinfection, additional chemicals are utilized to remove the chlorine prior to discharging the water into the bay. Because of the potential of endangering human health and the environment, this situation was reported to Department of Environmental Quality and the Department of Agriculture. Any questions can be directed to the City of Coos Bay Public Works Department at (541) 269-8918.
