Geneva Wastewater Treatment Plant - Executive Summary |
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The Geneva Wastewater Treatment Plant's (WWTP) accidental release prevention policy involves a unified approach that integrates technologies, procedures, and management practices. At the facility, we handle chlorine which is considered hazardous by EPA. While chlorine can be potentially hazardous, years of development and progressive safety practices make chlorination a safe, reliable, and effective method of disinfection. It is our policy to adhere to all applicable Federal and State rules and regulations. Safety depends upon the manner in which we handle chlorine combined with the safety devices inherent in the design of this facility combined with the safe handling procedures that we use and the training of our personnel. Our emergency response policy involves the preparation of emergency procedures that includes procedures for notification of the local emergency response agencies and notification of any potentially affected neighbors. The plan is in compliance with the EPA Emergen cy Response Program requirements. The Geneva WWTP is an activated sludge type of secondary treatment that converts wastewater into properly treated effluent. In particular, the plant is designed to reduce the biochemical oxygen demand (BOD) and suspended solids from an average daily inflow of 1.215 million gallons of wastewater. The Plant consists of an administration building, chlorination building, raw waste lift station, bar screen, package type activated sludge treatment unit, chlorine contact unit, aerobic sludge digestion facilities, and sludge drying beds. The amount of chlorine handled at the facility is one one-ton container and twelve 150-lb cylinders. Wastewater treatment operators inspect the facility and safety equipment daily. The offsite consequence analysis includes consideration of two chlorine release scenarios identified as "worst-case release" and "alternative release". EPA defines the first scenario as "the maximum quantity in the largest vessel ... is released a s a gas over 10 minutes," due to an unspecified failure. The alternative release is defined as "more likely to occur than the worst-case scenario". The assessment includes atmospheric dispersion modeling to determine the distance traveled by the chlorine released before its concentration decreases to the toxic endpoint selected by EPA as 0.0084 mg/l, which is the Emergency Response Planning Guideline Level 2 (ERPG-2). Also, the potentially affected populations and environmental receptore must by estimated. The worst-case release scenario at the Geneva WWTP involves a failure of a one-ton cylinder (a total of 2,000 lb of chlorine). The offsite consequence analysis for this scenario was performed following conditions predefined by EPA, namely the release of the entire amount as a gas in 10 minutes, use of the one-hour average ERPG-2 as the toxic endpoint, and consideration of the population residing within a full circle with radius corresponding to the toxic endpoint distance. Also EPA- mandated meteorological conditions, namely Stability F, wind speed of 1.5 m/sec, highest daily maximum temperature of 116 degrees F, and average humidity of 65% were used. The distance to the toxic endpoint is 1 mile and the estimated residential population affected is 271. The alternative release scenario involves a relief valve failure. The amount of chlorine released is 150 lb at an average rate of 5 lb/min released for 30 minutes. Toxic endpoint to the ERPG-2 level was obtained. The meteorological conditions used were Stability D, wind speed 3 m/s, average air temperature 77 degrees F, and average humidity of 65%. The estimated distance traveled to the toxic endpoint is 0.1 mile and the estimated residential population affected is 3. Modeling for the worst-case and alternative release scenarios were performed using EPA RMP*Comp. Our general accidental release prevention program is based on the following key elements: * Training of the operators * Preventive maintenance progra m * Use of effective operating procedures * Implementation of an inspection program Chemical-specific prevention steps include awareness of the hazardous and toxic properties of chlorine and the presence of chlorine detectors. No accidental releases of chlorine have occured at this facility in the past five years. The facility's emergency response program has been coordinated with the local fire department and emergency management agency. The program includes quidelines for personnel in the event of an emergency situation and includes procedures for notification of proper authorities. A vulnerability analysis was conducted at the WWTP to determine various factors that could create emergency situations and to outline the proper procedures for responding to each situation. |