Northwest Wastewater Treatment Plant - Executive Summary |
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NORTHWEST WASTEWATER TREATMENT FACILITY EXECUTIVE SUMMARY The Northwest Wastewater Treatment Facility is a facility whose primary activity is the treatment of wastewater. The Facility uses one regulated substance, chlorine (CAS 7782-50-5) as a disinfectant to treat wastewater during the chlorination process. The chlorination process consists of chlorine storage and the chlorination system used to disinfect the wastewater. The chlorination process begins with the withdrawal of chlorine from the chlorine cylinders by a vacuum created by vacuum regulators mounted on the cylinders. The chlorine gas travels through PVC pipes to chlorinators, where the chlorine supply is regulated and measured. From the chlorinators, chlorine is mixed with reuse water by chlorine injectors to produce a solution which is injected into the effluent water for disinfection. The hazard assessment was performed on the chlorination process using the United States Environmental Protection Agency (USEPA) RMP*CompTM. Model. The worst-case release scenario was assumed to be the release of a one ton cylinder for a duration of 10 minutes in an enclosed building. The alternative release scenario selected for the Facility was a failure scenario developed during the process hazard review and analysis. In this scenario, a 0.25-inch diameter whip connecting a one-ton cylinder to the chlorination manifold is sheared off, creating a leak in the system. The Facility has the capability of responding to and stopping the leak within one hour of detection. For both scenarios, the off-site consequence analysis indicated that off-site receptors could be potentially impacted by the release of chlorine. Although off-site areas would be impacted, we believe that safety procedures and mitigation measures will reduce the potential for off-site consequences and subsequent risks to the surrounding community. Our safety devices include chlorine leak detectors, alarms, and an automatic system shu t-off feature triggered by a loss in system vacuum. In addition, the chlorine cylinders are housed in a building with exhaust fans and vents which would dilute the chlorine gas concentration should a release occur. In order to fulfill the requirements of the Risk Management Program (RMP), we have developed an accidental release prevention program and emergency action plan for our facility. The accidental release prevention program satisfies the requirements for the EPA RMP and the Occupational Safety and Health Administration's (OSHA) Process Safety Management (PSM) program. The prevention program ensures that our facility is operated under safe conditions and that any risk of an accidental release of chlorine is minimized. The program has been written to reduce the potential of an accidental release due to human error, or equipment failure at our facility. In order to prevent the release of chlorine due to human error, our prevention program ensures that operating procedures are current and reviewed annually. Training also plays a vital part in our program. Employees and contractors working near or on the chlorination process are required to be trained in the chlorination process and the hazards of chlorine. To prevent equipment failure that could result in an accidental release, our program ensures that equipment inspections, tests, and preventive maintenance in accordance with accepted engineering practices and includes manufacturer's recommendations. All chlorine cylinders are examined upon delivery and are rejected if there are any signs of damage. In addition, equipment pertaining to the chlorine process is visually inspected daily. The potential for a chlorine release is greatly reduced in the chlorination process due to the use of a vacuum system from the point of chlorine withdrawal to its point of application. In the event that there is a failure in chlorination equipment, the system will automatically shutoff (i.e. failsafe). All existin g and proposed future chlorination equipment have been designed according to applicable standards and codes. The Facility maintains records and documentation on equipment inspection and tests. Precautions are taken to ensure that new equipment and processes are inspected and tested, that all changes on the process are authorized, and employees are informed of changes. The Facility performed a Process Hazard Analysis (PHA) to address the hazards in the chlorination process and to evaluate and control where the potential for a chlorine release exists. Employees were involved in determining hazards of the process and subsequent consequences. The chlorination process was found to be operating safely and no changes were recommended. Active employee participation will ensure the success of the RMP at our facility. Employees have been assigned various tasks to ensure that all elements of the RMP are implemented. We have developed many different forms to assist employees in recordin g and documenting the various elements of the RMP. At the time of the submittal of this Risk Management Plan, there have been no accidental releases of chlorine at our facility in the past five years. However, in the event that there is an accidental release of chlorine, an Emergency Action Plan has been written in compliance with 29 CFR 1910.38. The Facility is also included in the community emergency response plan. Employees at our facility do not respond to accidental releases of chlorine, but coordinate with outside responders. Therefore, in accordance with 40 CFR 68.90, an Emergency Response Program is not required for our facility. In the event that a chlorine release occurs, all employees are required to evacuate the process area and report the incident. The emergency action plan consists of evacuation procedures, facility emergency numbers, and coordination with Indian Rocks Fire Department. The plan also addresses notification procedures to the public and the local em ergency response agency. We conducted a neighborhood open house under the Local Emergency Planning Committee's (LEPC) Safety Street program and are willing to conduct tours of our facility for members of the public. |