Bellingham Water Filtration Plant - Executive Summary |
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Source The City of Bellingham Water Filtration Plant treats and supplies water from Lake Whatcom to the City of Bellingham. After filtration, the water is treated with chlorine as disinfectant. Chlorine is the only chemical at the Water Filtration Plant regulated by the Risk Management Program (RMP). The chlorine supply system is closely monitored and controlled to prevent accidental releases to the environment. It is City of Bellingham's policy to manage the chlorine process "using the highest standards for the protection of our people, our customers, the community, and the environment in order to ensure a safe and effective facility. Regulated Chemical The Water Filtration Plant uses chlorine for disinfectant in the public water supply. One ton chlorine containers are brought to the plant and connected to a manifold supply. Chlorine gas is supplied under vacuum to the water supply. The amount of chlorine in the supply water is carefully controlled using computerized controll ers, monitors and continuously supervised by certified operators. Accidental Release Prevention and Emergency Response The toxicity of chlorine at high concentrations make it necessary for the City to observe certain safety precautions to prevent unnecessary human exposure, and reduce the threat to the personal health of our employees as well as nearby members of the community. It is the City's policy to adhere to all applicable federal and state rules and regulations. Safety depends upon the manner in which we handle toxic chemicals including equipment design and safe handling procedures used to operate the equipment. The City's release prevention program is based on four principles; inherently safe design, effective written procedures, training, and the goal of continuous improvement. The chlorine storage and handling equipment meets or exceeds design codes and standards as well as incorporating good engineering practices recommended by The Chlorine Institute. Written operating and maintenance procedures are prepared and reviewed annually for accuracy and safety. Operating and maintenance personnel are thoroughly trained on proper procedures and safety hazards, and are provided with regular refresher training. The City has developed a comprehensive Emergency Response Program. In the event of an accidental release , the emergency response plan includes notifying the Bellingham Fire Department. Annual drills are conducted with the Bellingham Fire Department to review response actions in the event of an accidental release. Plant personnel receive regular classroom training on implementation of the response plan in addition to participating in training exercises. Worst and Alternative-Case Release Scenarios The worst-case release scenario from the Water Filtration Plant involves a catastrophic failure and release of the entire contents of a 1-ton liquid chlorine container. Using EPA's dispersion modeling program, RMP*Comp, the maximum distance downwind fr om the chlorination process to an endpoint concentration of 3 ppm chlorine is 1.3 miles. The worst-case impact distance is calculated using EPA mandated assumptions which are conservative. The worst-case analyses assumes that the release will occur during very stable climatic conditions not normally observed. The alternative release scenario was developed during a detailed Process Hazard Analyses involving operating, and maintenance personnel. The alternative release scenario is intended to represent the largest release that could reasonably be expected to occur. The alternative release selected was the a damaged vacuum regulator valve on the chlorine gas supply line. The amount of chlorine released was estimated at 540 pounds based on the evaporative heat capacity of chlorine over a period of 3.6 minutes. Using EPA's RMP*Comp model, it is calculated that this release could exceed 3 ppm chlorine up to 0.2 miles downwind. Five-Year Accident History During the five year period between May 1994 and June 1999, the Water Filtration Plant has had no documented reportable release of chlorine. |