Empire Treatment Plant Upset September 20, 2017
Last Friday, the City of Coos Bay reported that the Wastewater Treatment Plant #2, located at 100 Fulton Avenue in Empire, experienced a plant upset. You may recall that the same plant reported an upset earlier this year. However, some of you may not know what an “upset” signifies. This is a term that our wastewater operators use when they don’t know what is the cause, but they do know that something is affecting the process treatment. The technical definition for a plant upset is, “A plant outage caused by some kind of operational disruption and/or failure on the course of its performance.”
The upset that occurred last Friday and earlier this year caused the micro-organisms that are utilized in the secondary treatment process to be killed off. This means that the effluent that was discharged to the bay did not receive full treatment, but rather partial treatment (the effluent went through primary treatment and was disinfected). The micro-organisms, otherwise referred to as “bugs” or “the zoo”, consume the organic matter in the wastewater and in the case of Plant #2, this process occurs in the secondary treatment phase. One task of our wastewater operators is to keep the balance of “bugs” and food (organic matter) in line. If there are not enough or if there are too many “bugs”, it will affect the quality of treatment.
For the upset that occurred earlier this year, the cause could not be conclusively identified. It is assumed that some sort of illegal discharge to the sanitary sewer system caused the upset. With respect to last Friday’s upset, an investigation is pending. However, because the City has two plants, our operators quickly mobilized and repopulated “the zoo” at Plant #2 with “bugs” from Plant #1.
Due to the potential of endangering human health and the environment this situation was reported to Department of Environmental Quality, Coos County and Wellness, Oregon Department of Agriculture, and a public service announcement was distributed informing the public of the plant upset. Additionally, signs were posted at the treatment plant.
The existing Plant #2 is old and many of the components are past their useful life. The City is currently under construction of a new treatment plant which will replace the existing outdated plant. The new plant will be located one block away at the northeast corner of Empire Boulevard and Fulton Avenue. The new plant will have greater capacity and newer wastewater technology as it relates to process and disinfection.
