Surface Water Treatment Plant - Executive Summary |
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RELEASE PREVENTION AND EMERGENCY REPONSE POLICIES The City of Henderson Surface Water Treatment Plant (SWTP) was under construction during the development of this Risk Management Plan (RMP). The SWTP is scheduled to commence operations during the first quarter of 2001. However, this Executive Summary is written in present tense format as though the facility is currently conducting operations. The City of Henderson utilizes liquefied chlorine gas in offering municipal surface water treatment services to its customers. This highly regulated municipal activity includes strict adherence to the following requirements: 1. The use of equipment and components designed and installed for chlorine gas service. 2. Training and certification by a state agency of operating personnel in the operation of a surface water treatment plant. 3. The coordination of City of Henderson personnel with local emergency response personnel in the event of an accidental release of chlorine from the SWTP. S TATIONARY SOURCE AND REGULATED SUBSTANCES The chlorine is stored at the SWTP in pressurized ton containers secured to an engineered storage cradle mounted onto a covered concrete pad. The City of Henderson utilizes a vacuum-regulated system to deliver the chlorine from the ton containers to the water injection system. WORST CASE/ALTERNATIVE CASE SCENARIO ANALYSES INCLUDING ADMINISTRATIVE CONTROLS AND MITIGATION MEASURES TO LIMIT THE DISTANCES FOR EACH REPORTED SCENARIO The worst-case release scenario involves the failure of one ton container, resulting in the release of 2,000 pounds of chlorine gas. The distance to the toxic endpoint is 3.0 miles. The alternative-release scenario involves the release of 4,000 pounds of chlorine gas resulting from a leak in a vacuum regulator mounted onto one of two ton containers connected in parallel service. The distance to the endpoint is 0.3 miles. The City of Henderson limits its inventory of chlorine at the SWTP to three ton containers. The vacuum-regulated system allows two ton containers to be in service and one ton container to be in standby. PREVENTION PROGRAM AND CHEMICAL SPECIFIC PREVENTION STEPS The City of Henderson SWTP was designed, installed, and is operated in accordance with applicable codes, standards, and guidelines which include: 1. The use of ton containers authorized by the Department of Transportation (DOT) for liquefied chlorine gas service. 2. The use of container shut-off valves and pressure relief devices meeting the requirements of the Chlorine Institute (CI) for liquefied chlorine gas service. 3. The inspection, testing, repair, or replacement of the ton containers, valves, and relief devices in accordance with DOT and CI requirements. The vacuum-regulated system utilized at the City of Henderson SWTP is extremely safe since it is designed to eliminate the release of chlorine gas downstream of the vacuum regulator, which is mounted directly onto the ton container. The City of Henderson us es operating procedures developed to ensure that the ton containers are not dropped, improperly installed, or otherwise damaged, during unloading and loading, handling, storage, and use at the SWTP. These procedures are reviewed and revised as needed to reflect the system configuration, as well as to incorporate improvements or changes in industry and safety codes and standards. Trained personnel are used in the maintenance of the chlorine system components such as the vacuum regulators. Maintenance procedures are reviewed and revised as needed to comply with industry and safety codes and standards. The SWTP is equipped with chlorine gas detectors and audible alarms within the vicinity of the chlorine system components. This alarm system will assist in alerting facility personnel in identifying and responding to a release of chlorine. The City of Henderson conducts periodic hazard reviews and compliance audits in accordance with the RMP Rule. FIVE YEAR ACCIDENT HISTORY The City of Henderson SWTP was under construction during the preparation of the RMP. Therefore the Five-Year Accident History Determination is not applicable. EMERGENCY RESPONSE PROGRAM The City of Henderson SWTP is included in the community emergency response plan developed under 42 U.S.C. 11003. Appropriate mechanisms are in place to notify emergency responders when there is a need for response. PLANNED CHANGES TO IMPROVE SAFETY There are no changes planned at this facility at this time. |