Coshocton Water Treatment Plant - Executive Summary |
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The City of Coshocton, Ohio is committed to the RMP requirements under 40 CFR Part 68 and recognizes the responsibility to prevent harm to employees and the public due to a chlorine release. Coshocton's accidental release prevention program integrates management practices, safety procedures, employeee participation, process safety and operating information, process hazard analysis and compliance auditing, pre-start up reveiws, mechanical integrity, management of chancge procedures, incident investigation, emergency planning and response, and updating practices and procedures.Applicable requirements for Program 3 Risk Management Programs are adhered to. The emergency response program is tailored with respect to the available emergency responders and the Coshocton County LEPC and includes notification procedures as well as plant evacuation procedures. The chlorination system for the Coschocton Water Treatment Plant is used to disinfect drinking water. This water is supplied to the re sidents and businesses in or near the City. The chlorination facilities include a cylinder storage room for one ton cylinders, various safety equipment and controls, a chlorinator room with two chlorinators, and the necessary cylinder handling equipment. Normally chlorine is supplied from two one ton cylinders connected to the process feed piping. The cylinders in service are controlled automatically using a switchover device that limits operation from a single cylinder. Plant operators check the operation of the chlorination system at least once each shift and respond immediately to trouble or warning alarms. The offsite consequence analysis considers two chlorine release scenarios identified as the worst case scenario and the alternate release scanario. Predictive release information was obtained using EPA's RMP*Comp model to identify the distance to endpoint for a potential chlorine release. The worst case scenario involves a failure or rupture of a one ton cylinder releasing the entire contents of the cylinder within ten minutes. The distance to endpoint was estimated to be 0.72 miles from the chlorination facilities assuming a wind speed of 1.5 meters/second and atmospheric stability class F. The endpoint determination includes enclosure of the cylinder within the storage room. The potential population affected by the worst case scenario was estimated to be 1,160 persons. The alternate release scenario involves a potential pipe leak where 1,845 pounds of chlorine gas may be released during a 15 minute accidental release. The distance to endpoint was estimated to be 0.2 miles from the chlorination facilities assuming a wind speed of 3.0 meters/second and atmospheric stability class D. The endpoint determination includes enclosure of the cylinder within the storage room. The potential population affected by the alternate release scenario was estimated to be 433 persons. Actuation of the chlorine gas detectors was considered to be an active mitigation measure. Additionally, the chlorine gas piping is vaccum tubing connected directly to the chlorine cylinders. A loss of vacuum in the tubing immediately stops the flow of chlorine gas from the cylinders and virtually elinimates the possibility of a chlorine release due to a piping leak. The Coshocton Water Treatment Plant Risk Management Program has the key elements listed below. These elements are aimed at preventing a chlorine release from the chlorination system. -high level of operator training and maintenance training, -an established preventive maintenance program, -implemetnation of an audit and inspection program, -use of effective written operating procedures, -implemetation of an employee participation program, -use of emergency air supply and cylinder leak kits, -performance of process hazard analysis and compliance auidting procedures, -use of process alarms and emergency shut down procedures, - annual chlorine safety training by the chlori ne supplier, -and quartely demonstration and practice sessions using the emergency air supply. No accidental releases of chlorine gas have occurred at the Coshcoton Water Treatment Plant in the past five years. In fact, the current staff stated that no chlorine releases have occurred at the plant to the best of their knowledge. An emergency response program is established and is coordinated with the Coshocton County LEPC. The program includes plant evacuation procedures, emergency notification procedures for responders, and a notification plan. Plant evacuation drills are performed in accordance with 29 CFR 1910.38. Emergency response drills are performed in accordance with LEPC schedules. Recommendations for changes from the process hazaed analysis and the compliance audit are listed below. These recommendations are planned for implementation by September 1, 1999. A chlorine gas scrubber was recommended by a consultant to further reduce chlorine releases to the environment . The scrubber is being considered by the City for future installation. -emergency response training is needed for plant employees, -gas detector alarms should be tested monthly, -valves, piping, and major components need to be properly labeled, -cylinders should be stored with the valves positioned vertically to reduce the possibility of liquid leaks. |