Clarksburg Wastewater Treatment Plant - Executive Summary
Clarksburg Wastewater Treatment Plant Risk Management Plan Executive summary. |
The Clarksburg wastewater treatment system utilizes chlorine gas for disinfection purposes and sulfur dioxide for dechlorination of treated wastewater prior to discharge to the West Fork River. The facility utilizes one ton cylinders of chlorine and sulfur dioxide, which are received at the facility on a once-per-each six-week basis. Up to nine (9) cylinders of chlorine and up to two (2) sulfur dioxide cylinders are maintained on-site at any one time. All cylinders are stored inside the wastewater treatment plant chlorine or sulfur dioxide cylinder storage rooms. The process utilizes one cylinder on-line at any one time. Additional cylinder(s) is (are) connected to an automatic transfer system. The sulfur dioxide system has a maximum of 2 cylinders per system and there are two sets of three (3) cylinders each for the chlorine system. The automatic transfer system allows the second or third cylinde
r to go on-line as soon as the chlorine/sulfur dioxide from the first cylinder has been totally utilized. The average chlorine usage rate at this facility is 150 lbs. per day with a maximum possible feed rate of 600 pounds per day. The sulfur dioxide normal feed rate is 5 to 10 pounds per day with a maximum possible feed rate of 80 pounds per day. The Clarksburg wastewater 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 for minimal potential for leaks of chlorine gas through the piping. The facility has a preventive maintenance program, which is designed to maintain the equipment that handles chlorine gas in a good operating mode. The Clarksburg wastewater system also utilizes a Wallace and Tiernan (WT) sulfonator system. This system operates such that the sulfur dioxide transfer from the cylinder to the sulfo
nator is under vacuum versus pressure. This type of arrangement provides for minimal potential for leaks of sulfur dioxide gas through the piping. The physical state of both chemicals discharged from the one ton cylinders is gas versus liquid, which is controlled by the connection to the one ton cylinders. The facility has a preventive maintenance program, which is designed to maintain the equipment that handles chlorine gas or sulfur dioxide gas in a good operating condition. Cylinders are received from the vendor and the transfer of the cylinders from the truck to the appropriate storage building is always performed during daylight hours, and is attended by the truck driver and a Clarksburg wastewater treatment plant operator. The Clarksburg wastewater treatment plant is not continuously manned, but all alarms are monitored by a SCADA control system, which alerts off site personnel to alarm conditions for immediate response. There are two chlorine sensor systems located at the f
acility. 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 room are designed with exhaust fans that automatically start if a chlorine release is identified by the sensors. There are two sulfur dioxide sensor systems located at the facility. These sensors are designed to detect any sulfur dioxide release within either the sulfur dioxide cylinder storage area or the sulfanator room. Both the sulfanator room and sulfur dioxide storage room are designed with exhaust fans that automatically start if a sulfur dioxide release is identified by 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 60 lbs. per hour of chlorine gas or sulfur dioxide gas could be released from one cylinder.
EMERGENCY RESPONSE PROCE
In the event of a severe chlorine release, CWWTP employees are instructed to call 911 and request assistance from the Clarksburg Fire Department. The 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, CWWTP has a contract with Chemply of Pittsburgh, PA. Chemply provides emergency response to any chlorine or sulfur dioxide releases. Chemply personnel can be on-site within 1.5 hours of notification of a need. Once the chlorine or sulfur dioxide usage area has been adequately ventilated and the release of gas stopped, CWWTP personnel will enter into the area to perform the repair work necessary. CWWTP personnel have been instructed to never enter into a chlorine or sulfur dioxide usage area in the event of an alarm situation. Should community evacuation or shelter in place become necessary, CWWTP will utilize the
Harrison County Office of Emergency to coordinate the evacuation/shelter in place activity.
CWWTP personnel receive annual chlorine/ sulfur dioxide awareness training from Chemply. This training is performed to insure that personnel understand the hazards of dealing with chlorine gas and are familiar with the routine tasks associated with their jobs, as well as aware of the emergency response procedures necessary to be followed in the event of a chlorine or sulfur dioxide gas release.
CWWT personnel are also provided with CPR training on an annual basis as well as basic first aid training every three years.
In the event of a release, either a catastrophic release or the alternate scenario type release, there would be an immediate impact of recreational area, in that the CWWTP is located adjacent to the West Fork River. This river is used for a variety of recreational purposes including boating & fishing.