City of Burnsville Water Treatment Plant - Executive Summary |
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Executive Summary 1. Accidental Release Prevention and Emergency Response Policies The City of Burnsville, MN Water Treatment Plant uses the chemical chlorine for the purpose of disinfection of the city water supply. Chlorine is considered hazardous by the Environmental Protection Agency (EPA.) The City of Burnsville is strongly committed to employee, public, and environmental safety. This commitment is important to an accidental release prevention program that includes areas such as design, installation, operating procedures, maintenance, and employee training associated with the chlorine storage and feed processes at our facility. It is our policy to comply with applicable Federal and state rules and regulations. Safety depends on the safe handling procedures that we use combined with the safety devices included in the design of this facility and the training of our personnel. If a release of chlorine should occur, we are coordinated with the Burnsville Emergency dispatcher and in turn the Burnsville Fire Department and Emergency Operations Coordinator, who will provide highly trained emergency response personnel to control and mitigate the effects of an unforeseen release. 2. The Stationary Source and Regulated Substances Handled The Burnsville, MN Water Treatment Plant has one regulated substance, chlorine, at the facility. Chlorine, a toxic gas stored under pressure as a liquid, is used for disinfection of the city's water supply. The maximum inventory of chlorine at our facility at any time is six - 2,000 pound tanks, for a total of 12,000 pounds. 3. The Worst-Case Release Scenario and Alternative Release Scenario, including administrative controls and mitigation measures to limit the distances for each reported scenario. To evaluate the worst-case scenario, we have used EPAs RMP Guidance for Waste Water Treatment Plants and RMP*Comp, ver 1.06. For alternative release scenario analysis, the release rate was estimated by The Chlorine Institute, Inc. using the SAFER/TRACER model, Pamphlet 64, edition 3, April 1998.The distance to endpoint is based on EPAs RMP Guidance for Waste Water Treatment Plants, Exhibit 4-12. Worst-Case Scenario - Failure of the largest chlorine storage tank when filled to the greatest amount allowed would release 2,000 pounds of chlorine. It is assumed that the entire contents are released as vapor in an outdoor setting within 10 minutes of tank failure. A rural setting was chosen as the topographical setting even though the City of Burnsville Water Treatment Plant appears to be located in an urban area. This decision was based on the fact that the Treatment Plant is located at the southern edge of the Minnesota River Valley. Since chlorine is a dense gas that is heavier than air, it will have a tendency to settle and flow to areas of lower elevation, such as the river valley. The river valley is a relatively open area with few obstructions, where the gas can travel freely. Under worst-case weather conditions, the maximum distance of 3.0 miles corresponding to an endpoint concentration of 0.0087 mg/l or 3 ppm (volume/volume) is reached. Alternative Release Scenario - An outdoor release of gas due to valve failure was considered for the alternative release scenario. It is assumed that mitigation occurs within one hour of the start of the release under neutral weather conditions. As in the worst-case scenario, a rural topographical setting was chosen. The more likely indoor release scenario was not chosen because it would not result in an offsite release above the endpoint value. The maximum distance to the endpoint concentration of 0.0087 mg/l or 3 ppm (v/v) is 0.2 miles. This release has the possibility of extending beyond the facility boundary, but is unlikely to occur. 4. The General Accidental Release Prevention Program and the Chemical-Specific Prevention Steps The Burnsville MN Water Treatment Plant has taken the necessary steps to comply with EPAs Accidental Release Prevention Rule requirements as specified in 40 CFR part 68. The Plant is also in compliance with OSHAs Process Safety Management of Highly Hazardous Chemicals Rule as specified in 29 CFR 1910.119. The chlorine cylinders are handled minimally outside of the facility and are stored indoors. The facility is designed with a chlorine detection system that automatically activates a scrubber system in the event of an indoor release. Additionally, a vacuum demand chlorine delivery system automatically stops the flow of chlorine if a piping or valve failure causes a vacuum loss. Water Treatment Plant operators are competent in the chlorine system operations and are trained in the hazards and operating procedures associated with the chlorine processes. 5. Five-year Accident History The Burnsville MN Water Treatment Plant has had an excellent record of preventing accidental releases over the history of the facility. There have been no documented releases over the last five years. 6. Emergency Response Plan E mergency Response by the Burnsville Water Treatment Plant employees will be limited to incidental releases only. The plant has coordinated emergency response actions with the City of Burnsville Fire Department and the emergency dispatcher. In the event of a catastrophic event, the City of Burnsville's comprehensive Emergency Operation Plan may be initiated. The plans are studied, practiced, and updated as needed. Both the Police and Fire/EMS departments are responsible for the EOP. 7. Planned Changes to Improve Safety As a result of the Process Hazard Analysis conducted at the facility and development of the PSM and RMP programs, a number of steps have been taken to improve safety at the plant. An improved mechanical integrity program has been developed to include daily and monthly inspection of key equipment components. All four flow regulators were replaced in 1998. The regulators are on a rotating schedule for replacement beginning in 2000. Changes have also been made to the facil ity and equipment to improve safety. Certification Statement The undersigned certifies that to the best of my knowledge, information, and belief after reasonable inquiry, the information submitted is true, accurate, and complete. _______________________________ __________________________ Signature Print name _______________________________ __________________________ Title Date |