Town of South Hill Regional WWTP - Executive Summary |
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The Town of South Hill, Virginia operates a wastewater treatment plant at 1015 Rocky Branch Road (formerly known as Route 642) in Mecklenburg County. This facility treats industrial and domestic wastewater from the towns of South Hill, LaCrosse, and Brodnax. The final process involved in the treatment of our wastewater is disinfection by the use of chlorine gas. Chlorine gas is used to eliminate any disease-causing organisms before the treated water is discharged into the receiving stream. Because chlorine is a toxic and potentially lethal gas, we are required to submit a Risk Management Plan to EPA. This plan outlines the criteria we must follow in order to avoid, and also be prepared for, an accidental release of this hazardous gas. The following paragraphs summarize this plan and our policies related to the handling and use of chlorine. We are already in compliance with VOSHA's Process Safety Management rule which requires us to have many of the same elements in place as the Risk M anagement Plan. We also report annually to the Virginia Emergency Response Council under the Emergency Planning and Community Right-to-Know Act. This gives the state and local emergency responders information on the chemicals stored and used at our facility along with points of contact in case of an accidental chemical release. We have an emergency action plan coordinated with the local fire department to respond in the event of a chlorine gas leak. The plant is staffed 16 hours per day Monday through Friday and 12 hours per day on Saturday and Sunday. There is a gas detection system which will notify operators in the event a leak occurs when no one is at the plant. Personnel are trained what to do in case of an emergency and all chlorination equipment is inspected on a regular basis. The Risk Management Plan being implemented by EPA requires that we analyze the effects of a worst-case scenario as well as an alternative-release scenario. The worst-case scenario is required to show th e effect to the surrounding area of a total release from our largest container (2000 pounds). According to EPA's RMP COMP modeling software, a release of this magnitude would affect an area within a radius of 0.9 miles (4752 feet) of the plant. A release such as this is highly unlikely to occur, however, if it should, many homes and businesses in the radius would need to be evacuated until the gas dissipates. This would include the industries located in the Interstate Industrial Park as well as Dixie Warehouse. Interstate 85 and the Route 58 bypass would also need to be closed temporarily. The alternative release scenario is one which is more likely to occur than the worst-case scenario. In this case, we chose to model the effect of a release of 300 pounds of chlorine from a cylinder which was leaking due to improper mounting of the chlorine gas regulator (operator error). When we used EPA's modeling program for this release, it was determined that an area within a radius of 0.1 miles (528 feet) of the plant would be affected. Only the treatment plant would need to be evacuated in this instance. The chlorine gas at our plant is stored in metal cylinders which contain 2000 pounds of chlorine each. The cylinder by itself weighs nearly as much as the chlorine inside. There are never more than three cylinders (6000 pounds) on hand at a given time. An injector is used to create a vacuum which draws the chlorine gas out of the cylinder through a regulator mounted on the cylinder. This is very important in the fact that the chlorine gas is under a vacuum from the time it passes the regulator until the time it is injected into the stream. The regulator is designed with a diaphragm that will close automatically in the case of a loss of vacuum. Therefore, if there is a break in the piping between the tank and the injector, then the diaphragm will close, preventing any gas from escaping. This method of injecting chlorine reduces the possibility of a leak by providing that au tomatic shutoff. The town is very much aware of the hazards involved in the handling of chlorine. We are committed to the safety of our employees and the surrounding community. The equipment used to handle the cylinders and inject the chlorine into the water is up-to-date and well maintained. Our employees are trained in the handling and use of this hazardous gas and no expense is spared when it comes to equipment maintenance or training. The South Hill Regional Wastewater Treatment Plant went on line in July of 1986. Since that time we have had no reportable releases of chlorine gas. We are very proud of this fact and intend to do everything possible to maintain this excellent safety record. We continue to expand and improve upon our safety program. During the coming year we intend to focus on educating the public about our safety programs, particularly, the Risk Management Plan. |