Resolution No. 4793 - Laserfiche WebLink

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MWMC FACILITIES PLAN 2,2,4 Public Health Hazards Four types of potential public health hazards were evaluated for the WPCF: Air pollution restrlting from chlorine or sulfur dioxide releases at the facility Air pollution from other facility sources (e.g., wind-blown dust or combustion engine exhaust) · Worker or public exposure to chlorine or sulthar dioxide, or physical collapse of onsite buildings due to seksmic instability · Potential biohazard from spill of biosolids during offsite transport The first potential public health hazard (chlorine or sulfur dioxide release) ks addressed under EPA's Risk Management Program (RMP) Rule. This rule, developed in 1996 following guidance under the Clean Air Act Amendments of 1990, requires companies using more than threshold quantifies of certain flammable and toxic substances to develop a Risk Management Plan (RIvIP). Risk Management Plans include the following features (EPA, 2002): Hazard assessment detailing potential effects of an accidental release, an acddent history over the last 5 years, and an evaluation of worst-case and alternative accidental releases · Prevention program describing safety precautions and maintenance, monitoring, and employee training measures Emergency response program detailing emergency health care, employee training measures, and procedures for informing the public and response agencies if an accident occurs Chlorine and Sulfur Dioxide Usage at Existing Facilities Currently, the WPCF uses chlorine gas for disinfection of effluent prior to wastewater discharge into the W/llamette River. Cl'dorine has been an effective disinfectant at the WPCF. No chemical release accidents resulting in injury to facility workers or the public 1-~ave occurred in facility history. Disinfected wastewater has met permit requirements consistently since plant startup in 1984. Sulfttr dioxide gas ks used to dechlorinate WPCF effluent prior to discharge into the Willamette River. Sulktr diox/de is transported to the WPCF in pressurized 1-ton containers. It is metered by one to two sulfonators to the effluent channel just upstream of the pipe. The sttlfur dioxide system has proven effective in controlling chlorine residual to meet effluent requirements. A 2-ton capacity emergency scrubber is located in the chemical buddding. The neutralizing chemical in the scrubber used during a chlorine or sulfur dioxide leak is sodium hydroxide. The scrubber has been operational since plant startup.