Reservoir 6 Water Treatment Facility - Executive Summary |
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The Metropolitan District provides water to customers in Hartford, Connecticut and the surrounding area. To ensure that the water is safe for drinking throughout the distribution system, a small amount of chlorine is added as a disinfecting agent. Because chlorine can be hazardous if not handled properly, The Metropolitan District has established risk management programs for the protection of it's employees, the public and the environment. The chlorine present at this Metropolitan District facility is kept in one ton containers to minimize the potential for harm in the unlikely event of an accidental release. If such a release should occur, the public will be notified via state and local emergency management agencies. Worst-Case Release Scenario The Reservoir 6 Water Treatment Facility has conducted an offsite consequence analysis including a worst-case release scenario. As required by the EPA RMP regulations, the worst-case scenario is defined as the release of an entire one to n container as a gas in ten-minutes. Because all operations from unloading to use are fully enclosed in a building, the effects of the building in slowing the rate of release was considered in accordance with EPA RMP Guidance for Waste Water Treatment Plants. The mitigating affects of the building were considered by applying a factor of 0.55 to the release rate modeled for an unmitigated release as described above. This means that the chemical release rate from the building is 55% of the release rate from the source. This resulted in a projected release of 110 lbs./min. from the building to the outside air in about 18 minutes. The regulations require assuming worst-case wind speed and atmospheric conditions that result in the greatest projected impact distance. For the offsite consequence analyses, the "endpoint" concentration is defined by the Emergency Response Planning Guideline (ERPG-2) values developed by the American Industrial Hygiene Association (AIHA). AIHA defines the ERPG -2 value as, "the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms that could impair an individual's ability to take protective action." The endpoint (ERPG-2 value) established for chlorine is 0.0087 mg/L (3 ppm). For the wooded and hilly setting of the Reservoir 6 Water Treatment Facility, the potential distance to the endpoint concentration for the worst-case release is 0.9. miles, which extends offsite into residential areas. This distance was obtained from the EPA RMP*COMP offsite consequence analysis software developed by the EPA as a tool for risk management planning. A major release of the magnitude represented by this worst-case scenario is extremely unlikely because of the robust design of one-ton chlorine containers (they are designed to withstand transportation mishaps) and the rigorous maintenance and preven tion programs in place at the Reservoir 6 Water Treatment Facility. In fact, release reporting databases and water industry experience suggest that the worst-case release scenario as defined in the RMP regulations is so unlikely that it should not be used as the basis for emergency planning. A more reasonable potential release scenario for emergency planning is presented in "The alternative release scenario(s)" section below. Alternative Release Scenario A "credible worst-case" scenario was selected as the Reservoir 6 Water Treatment Facility alternative release scenario. This scenario assumes that the connection to one of the ton containers is completely severed and the resulting vapor release occurs within the building. The mitigating affects of the building were considered by applying a factor of 0.55 to the release rate modeled for an unmitigated release as described above. This means that the chemical release rate from the building is 55% of the release rate from the source. T his factor is recommended for modeling the effects of building mitigation in the EPA RMP Guidance for Waste Water Treatment Plants. This resulted in a projected release of 8.25 lbs./min. from the building or 495 lbs. of chlorine in an hour. The results of the process hazard analysis (PHA) and the facility's operating history suggest that even this credible worst-case is extremely unlikely to occur, but it can serve as the basis for emergency planning. The potential distance to the endpoint concentration for this alternate release scenario is 0.1 miles based on the EPA guidance, which extends offsite into residential and recreation areas. As with the worst-case scenario, actual distances and directions vary with terrain and weather conditions. Accidental Release Prevention Steps The Metropolitan District is committed to the well being of it's employees, the public, the environment and continued reliable operation and regulatory compliance. Based on this commitment, the Direct or of Water Treatment and Supply has assumed overall responsibility for the development and implementation of the Risk Management Program. Also, the Plant Superintendent has clearly defined accountability and responsibility for each of the prevention program elements to meet both EPA and OSHA Process Safety Management requirements. To ensure a worst-case or alternative release scenario does not occur, the Reservoir 6 Water Treatment Facility maintains a release prevention program with the primary focus of protecting plant employees and the public from the hazards associated with an accident or release involving chlorine. The multifaceted program includes the use of: ( chlorine detectors and alarms to rapidly alert operators to any problems; ( process safety information to document the safe process design; ( process hazards analyses to evaluate the chemical and process hazards; ( operating procedures to ensure that the system is operated safely; ( maintenance, inspection and testi ng to ensure that the system is maintained according to applicable standards and manufacturer's recommendations; ( training, hot work permits, contractor safety and employee participation programs to ensure that all employees and contractors working on and around the processes are aware of the hazards, can perform their job duties safely and know the actions to be taken in an emergency; ( management of change and pre-startup safety reviews to ensure that changes are documented, analyzed and kept within the design basis; ( incident investigation procedure to investigate each incident and "near misses" to determine root causes and make needed safety improvements; ( and periodic compliance audits to ensure that our programs are as they should to protect both employees, the public and the environment. Five-Year Accident History Within the past five years, the Reservoir 6 Water Treatment Facility has not had any accidental releases that resulted in property damage or OSHA recordable injur ies. The plant has maintained an excellent safety record throughout its operating history and we know of no chlorine release that has had adverse effects on the public. Emergency Response In the unlikely event that a chlorine release does occur, the Metropolitan District has an emergency response program that includes trained onsite emergency responders. Any emergency response would be coordinated with the regional response organizations and Local Emergency Planning Committee. If an emergency did occur, plant personnel would activate The Metropolitan District response team and notify the regional response organizations who would assist if offsite actions were needed or to help address the chlorine release. Maintaining A Safe Operation The management and employees of the Reservoir 6 Water Treatment Facility continually work to safely address the hazards of chlorine to protect employees and the community we serve. The Risk Management Program is maintained to reduce the risk of a ccidental releases and our goal is to never have an accidental release. Each year we will conduct safety training, review procedures, maintain the equipment and follow safe work practices. Periodically, we will audit our program, review our Process Hazard Analysis and coordinate with the community emergency response organizations. In addition to ongoing safety related activities, we will perform an annual review of safe work practices and conduct annual emergency response training sessions. We will also ensure that response equipment is properly maintained and operational. |