Post Point Wastewater Facility - Executive Summary |
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Source The City of Bellingham Post Point Treatment Facility treats the municpal wastewater from the City of Bellingham. As part of the treatment chlorine is used as disinfectant prior discharging the wastewater into Bellingham Bay. Chlorine is the only chemical at the Post Point Treatment Facility regulated by the Risk Management Program (RMP). The chlorine supply systems is closely monitored and controlled to prevent accidental releases to the environment. It is the City of Bellingham's policy to manage the chlorine process "using the highest standards for the protection of our peiople, our customers, the community, and the envrionment in order to ensure a safe and effective facility. Regulated Chemical The Post Point Treatment Facility uses chlorine for disinfectant in the sewage treatment process. One ton containers are brought to the plant and connected to a manifold supply. The amount of chlorine in the wastewater is carefully controlled using computerized controllers, moni tors 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 safety precautions to prevent unnecessary human exposure, and reduce the threat to the personal health or 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 recommeded by The Chlorine Institute. Written operating and maintenance p rocedures 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 personnnel 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 Post Point Treatment Facility 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 from the chlo rination process to an endpoint concentration of 3 ppm chlorine is 3.0 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 reasonbly be expected to occur. The alternative release selected was a damaged container during offloading from a truck. The amount of chlorine released was assumed to be the entire contents of the container, 2,000 lbs over a period of 13.3 minutes. Using EPA's RMP*Comp model, it is calculated that this release could exceed 3 ppm chlorine up to 0.6 miles downwind. Five-Year Accident History During the five year period between May 1994 and June 1999, the Post Poi nt Treatment Facility has had one documented reportable release of chlorine. The release occurred April 2, 1998 and resulted in a minor, short-term inhalation injury to one employee with no off-site impacts. |