Broad River Water Plant - Executive Summary |
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The Duke Water Systems Broad River Plant is a water treatment plant that provides drinking water to customers in the area of Rutherfordton, North Carolina. To ensure that our water remains safe throughout the distribution system to every tap, the Broad River Water Plant adds a small amount of chlorine as a disinfection agent. The concentrated form of chlorine is liquefied and stored in one ton containers. Before it is mixed with water, chlorine can be extremely hazardous if released to the air. Duke Water Systems is committed to protecting its employees, the public, and the environment from any accidental releases of hazardous materials used at its facilities. We have implemented safety, environmental protection, and risk management programs to prevent hazardous materials releases. If there is an accidental release, we will immediately call for emergency response to minimize the effect of the release and notify the public of any actions necessary to ensure public protection, thro ugh county emergency management agencies. Worst-Case Release Scenario The Broad River Plant 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 ton container as a gas in ten-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 Broad River Water Plant, the potential distance to the endpoint concentration obtained from EPA guidance for the worst-case release extends offsite into residential areas. There are no public facilities (i.e., churches, recreational and park areas, hospitals, prisons, or major office or industrial areas) or environmental receptors (i.e., national or state parks, forests, or monuments; officially designated wildlife sanctuaries, preserves, refuges, or areas; and Federal wilderness areas) within the worst-case area. 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 prevention programs in place at the Broad River Water Plant. 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 Broad River alternative release scenario. This scenario assumes that the vacuum regulator connection to the container is completely severed with the valve wide open resulting in a gas release through the maximum 5/16-inch valve body. 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. Based upon Exhibit 4-15 of the EPA RMP Guidance for Wastewater Treatment Plants, the potential distance to the endpoint concentration for this alternate rel ease scenario extends offsite into residential areas. There are no other public facilities or environmental receptors within this area. As with the worst-case scenario, actual distances and directions vary with terrain and weather conditions. Accidental Release Prevention Steps Duke Water Systems is committed to personnel safety, public safety, continued reliable operation and regulatory compliance. Based on this commitment, the Water Operations Manager has assumed overall responsibility for the development and implementation of the Risk Management Program. The Water Operations Manager has also 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 Broad River Water Plant maintains a release prevention program with the primary focus of protecting plant employees and the public from the hazards associate d with an accident or release involving chlorine. The multifaceted program includes the use of: ( vacuum feed of chlorine to minimize the chance of release if equipment fails; ( 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 testing 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 wi thin 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 working as they should to protect both employees and the public. Five-Year Accident History Within the past five years, the Broad River Water Plant has not had an accidental release of chlorine. The plant has maintained an excellent safety record and we know of no accidental release of chlorine throughout its entire 16-year operating history. Emergency Response In the event that a chlorine release does occur, the Broad River Water Plant has an emergency response program that coordinates emergency response with the Rutherford County Emergency Management Agency and the Cliffside Steam Station. If such a release did occur, plant personnel would contact the Rutherford County Emergency Management Agency and the Cliffside Steam Station. The Cliffside Steam Stat ion would dispatch a trained HAZMAT team to the site to handle the chlorine release. Maintaining A Safe Operation The Broad River Water Plant continually works to safely manage the hazards of chlorine to protect employees and the community we serve. The Risk Management Program will be maintained to reduce the risk of accidental releases and each year we will conduct 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 organization. |