Clarksburg Water Board - Executive Summary |
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The Clarksburg water treatment system utilizes chlorine gas for disinfection purposes. The facility utilizes one ton cylinders of chlorine gas which are received at the facility every two months with six cylinders delivered at any one time. Up to eight cylinders are maintained on-site at any one time. All eight cylinders are stored inside the water treatment plant chlorine cylinder storage building. The process utilizes one cylinder on-line at any one time. One additional cylinder is connected to an automatic transfer system. The automatic transfer system allows the second cylinder to go on-line as soon as the chlorine from the first cylinder has been totally utilized. The average chlorine usage rate at this facility is 300 lbs per day. The Clarksburg water system utilizes a Wallace and Tiernan (WT) chlorinator system. This system operates such that the chlorine transfer from the cylinder to the chlorinators is under vacuum versus pressure. This type of arrangement provides f or minimal potential for leaks of chlorine through the piping. The only section of the system which is not under vacuum is the piping from the cylinder valves to the cylinder manifold which is under pressure. The facility has a preventive maintenance program which is designed to maintain the equipment that handles chlorine gas in a good operating mode. Chlorine cylinders are received from the vendor and the transfer of the cylinders from the truck to the chlorine storage building is always performed during daylight hours, and is attended by the truck driver and a Clarksburg water treatment plant operator. The Clarksburg water treatment plant is continuously manned. There are two chlorine sensor systems located at the facility. These sensors are designed to detect any chlorine release within either the chlorine cylinder storage area or the chlorinator room. Both the chlorinator room and chlorine storage building are designed with exhaust fans that are manually started if a chlori ne release is identified by either of the sensors. The alternative scenario identified for this facility would be for a failure of the yoke piping which connects to the cylinder. If this piping and related regulator valve failed, a maximum of 50 lbs per hour of chlorine gas could be released from one cylinder. EMERGENCY RESPONSE PROCEDURES In the event of a severe chlorine release, CWTP employees are instructed to call 911 and request assistance from the Clarksburg Fire Department. The Clarksburg Fire Department personnel can respond within 5 minutes and have the adequate personal protective equipment to isolate valves in the event of such an incident. Regarding lower volume incidents involving minor leaks, CWTP has a contract with PB&S of Charleston, WV. PB&S, the supplier of chlorine cylinders to the facility, provides emergency response to any chlorine releases. PB&S personnel can be on-site within 2.0 hours of notification of a need. Once the chlorine usage area has been a dequately ventilated and the release of chlorine stopped, CWTP personnel will enter into the area to perform the repair work necessary. CWTP personnel will enter into the chlorine usage area in the event of an alarm situation to assess the condition and perform minor emergency response. The facility is covered under a generic emergency response implemented by the Harrison County Office of Emergency Services. The facility also maintains an emergency response plan for evacuation of employees in the event of an emergency and shut down of critical equipment. The supplier of chlorine cylinders may change on an annual basis. Any such change will result in revision to this risk management plan to insure that the current supplier is identified. TRAINING CWTP personnel receive annual chlorine awareness training from PB&S, the supplier of the chlorine cylinders. This training is performed to insure that personnel understand the hazards of dealing with chlorine gas and are familiar with t he routine tasks associated with their jobs, as well as aware of the emergency response procedures neceessary to be followed in the event of a chlorine release. The supplier of chlorine cylinders may change on an annual basis. Any such change will result in modification of this section of the risk management plan to insure that the current supplier is listed. AFFECTED AREA In the event of a catastrophic release of chlorine gas, one school, two hospitals, several residences, several business, and one recreational area would be affected. For an alternative scenario release, several adjacent residences would be affected. |