Snapfinger AWT Facility - Executive Summary |
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The Snapfinger Advanced Wastewater Treatment (AWT) Facility has prepared and implemented a Risk Management Program in accordance with the Chemical Accident Prevention Provisions of 40 Code of Federal Regulations (CFR) Part 68 to prevent the accidental release of chlorine and exposure to Snapfinger personnel and members of the community, as well as to the environment. This Risk Management Plan (RMP) encompasses all the elements of the Risk Management Program. The Snapfinger AWT Facility is located on the South River in DeKalb County, on Flakes Mill Road, south of the City of Decatur, Georgia. Chlorine is used to disinfect wastewater prior to discharge to the South River. A chlorinated water solution is pumped from the chlorinator room to the contact chamber, where it enters the wastewater system to provide disinfection. The facility stores chlorine in 1-ton (2,000 lb) containers. Chlorine containers are stored on a standby/on-line basis so that the chlorination process is continuo us. The chlorination process is continuously monitored for chlorine gas leaks and is equipped with an audible alarm to alert personnel that a release has occurred. Snapfinger AWT Facility personnel are trained to operate the chlorination process. The Snapfinger AWT Facility preventive maintenance program ensures that equipment related to chlorine operations is maintained as fully operational. Accidental release prevention and emergency response policies at the Snapfinger AWT Facility emphasize safety, training, and maintenance. A worst-case release scenario was estimated, per the United States Environmental Protection Agency (EPA) guidance, to provide the greatest distance in any direction to the established toxic endpoint. The worst-case release quantity, established by the regulations, is the greatest amount of chlorine held in a single vessel. In accordance with 40 CFR ' 68.25, it is assumed that the gas is released over a 10-minute period. No administrative controls or active mitigation measures were included for the worst-case release scenario. Tables from the EPA and Chemical Emergency Preparedness and Prevention Office (CEPPO) Risk Management Program Guidance for Wastewater Treatment Plants (EPA 550-B-98-010; October 1998) (EPA Guidance tables) were used to determine the distance to the toxic endpoint for the worst-case release scenario. Public receptors were estimated within this radius. No environmental receptors were identified. The five-year accident history was evaluated to determine a likely alternative release scenario. Since no accidents have occurred in the last five years (since 1994), a review of common accidents that have occurred at other facilities involving 1-ton containers was considered. It was determined that the most likely scenario for a chlorine release is a ruptured flexible connector or "pigtail." Under the alternative release scenario, it is assumed that chlorine gas is released through the 0.25 inch diameter pigtail. Us ing EPA Guidance Tables, the release rate and the distance to the toxic endpoint were determined. No public or environmental receptors were identified within this radius. The Snapfinger AWT Facility has developed an accidental release prevention program. The primary safeguard is the chlorine leak detection system located at the chlorine building. The leak detection sensors are manually checked on a monthly basis to ensure they are functioning properly. Operators inspect the facility every two hours to ensure the chlorine feed system is also functioning properly. Audible alarms will sound at the operator control room located at the main building if the chlorine leak detection system detects an ambient air chlorine concentration of 3 to 4 parts per million or greater. The Snapfinger AWT Facility has several programs in place to prevent accidental chlorine releases. Specifically, the facility trains operators on the proper operation of the chlorination process, uses state-of-the-a rt safety equipment, and implements a preventive maintenance program to ensure the process equipment is operating properly. A review of the hazards associated with the Snapfinger AWT Facility chlorination process was conducted. Results of the review and recommendations identified during the hazard review process that would improve safety at the facility are documented in the Hazard Review Checklist Analysis. The Snapfinger AWT Facility personnel are trained to respond to an incidental release of chlorine. However, in the event that a release is beyond the control of the operators, personnel have a mechanism in place to notify the DeKalb County Fire Services Hazardous Materials (Haz Mat) Team emergency responders. Safety equipment available on-site includes Self-Contained Breathing Apparatus (SCBA) and ton container emergency repair kits ('B' Kits). |