Jefferson Parish East Bank WWTP - Executive Summary |
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JEFFERSON PARISH EAST BANK WASTEWATER TREATMENT PLANT HARAHAN, LOUISIANA L0066630 The Jefferson Parish East Bank Wastewater Treatment Plant (EBWWTP) 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 EBWWTP 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 EBWWTP is located in Harahan, Louisiana, 10 miles west of New Orleans, Louisiana. Chlorine is used to disinfect the wastewater prior to discharge to the Mississippi River. The facility is designed to treat an average wastewater flow of 33 million gallons per day (MGD) in dry flow and 56 MGD in wet flow. Chlorine at the facility is contained in one 55-ton railcar. The chlorine building and railcar area at EBWWTP have separate chlorine ala rm systems, which continuously monitor the area for chlorine gas leaks. The facility is equipped with visible and audible alarms to alert personnel if a release occurs. EBWWTP personnel are routinely trained to safely operate the chlorination system. The EBWWTP preventive maintenance program ensures that equipment related to chlorine operations is fully operational. Accidental release prevention and emergency response policies at the EBWWTP emphasize safety, training, and maintenance. A worst-case release scenario was estimated, based on 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 this quantity is released over a 10 minute period. No administrative controls or mitigation measures were considered f or 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. The population (public receptors) was estimated within this radius using 1990 U.S. Census information. Environmental receptors are also located within this radius. The five-year accident history was investigated to determine an alternative release scenario. Since no accidents have occurred in the last five years (since 1994), the EPA Region VI was consulted to determine likely accidents involving chlorine railcars, which have occurred at other facilities. It was determined that the most likely scenario for a chlorine release would be a broken whip. Under the alternative release scenario, it is assumed that the whip is broken. Liquid chlorine is r eleased from the broken whip and the underground piping for approximately one minute. The one minute release time is the maximum expected period of time that would have elapsed between the time the chlorine leak detector detects a 1 ppm ambient air chlorine concentration and the interlocked pneumatic control valve is closed. This scenario results in a calculated chlorine release rate of 175 lbs/min. Eighty pounds is a conservative estimate of the amount of chlorine contained in the whip and the underground piping. An active mitigation measure, the pneumatic control valve interlock, was included for this release scenario. An air dispersion modeling program was used to determine the distance to the toxic endpoint for the alternative release scenario. The number of public receptors is estimated within this radius. No environmental receptors are located within this radius. The EBWWTP has developed an accidental release prevention program. The primary safeguard is the chlorine leak detection system located at the chlorine building and railcar. The leak detection sensors are manually checked on a weekly basis to ensure they are functioning properly. Operators inspect the facility every two hours to ensure the chlorine feed system is functioning properly. Audible and visible alarms are located at the chlorine building and at the railcar. A yellow light illuminates when an ambient air chlorine concentration of 0.5 ppm is detected. A red light illuminates and the audible alarm sounds when an ambient air chlorine concentration of 1.0 ppm is detected. The EBWWTP has several measures built into the chlorine system to control a chlorine release. A valve, located after the expansion chamber, is interlocked with the building leak detector at the evaporator inlet. This valve will close in the event that a leak is detected. A pressure relief line will allow chlorine to escape through the back wall of the building from the evaporator inlet line. This pressure reli ef occurs when too much chlorine is forced into the chlorinators. As noted above, the railcar leak detector is interlocked with the whip control valve. All valves are controlled pneumatically with a compressor. A power loss or loss of air to the valves will cause the valves to close. This type of valve is referred to as "fail close." The EBWWTP has established several programs to prevent accidental chlorine releases. Specifically, the facility trains operators to properly operate the chlorination process, uses state-of-the-art safety equipment, and implements a preventive maintenance program to ensure the process equipment is operating properly. The EBWWTP personnel are trained to respond to an incidental release of chlorine. In the event that a release is beyond the control of the operators, personnel have a mechanism established to notify the Jefferson Parish Emergency Management Department. Safety equipment available on-site includes self-contained breathing apparatus (SCB A), a Cascade supplied breathing air system, and emergency valve capping Kit 'C' (C Kits). |