City of Tracy Wastewater Treatment Plant - Executive Summary |
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FEDERALLY MANDATED RMP SUBMISSION EXECUTIVE SUMMARY Page 1 of 4 1. Accidental Release Prevention and Emergency Response Policies This facility handles chlorine and aqua ammonia, which are considered hazardous materials. The properties of both materials make it necessary to observe safety precautions in handling to prevent human exposure and to reduce the threat to the facility's workers and nearby members of the community. It is the facility's policy to adhere to all applicable Federal and State of California rules and regulations. Safety depends upon the safe procedures used to handle chlorine and aqua ammonia; the safety devices and systems designed and constructed into the facility; and the training of the pertinent personnel. 2. Stationary Source and Regulated Substances Handled The chlorine gas is used to disinfect water treated at the FWTP; to disinfect water pumped from the associated wells into the City's water distribution system, and to disinfect the water in the Cit y's swimming pool. Chlorine is delivered in one-ton containers for use at the FWTP, and in 150-lb cylinders for use at the wells, booster pump stations, and swimming pool. All chlorine is delivered to the Chlorine Storage Area at the FWTP. The one ton containers are used at this location, and the 150-lb cylinders (up to 15 at a time) are stored at this location and then transported to their various points of use. Aqua ammonia, at 24.5 % strength, is used at the FWTP to aid in the disinfecting of treated water. The aqua ammonia system consists generally of a steel storage tank, appurtenances; interconnecting buried piping, a metering pump, and pump discharge piping. There is no detection system for ammonia. Monitoring and control of the system is manual. The aqua ammonia at 24.5 % by weight is injected into the water at several points in the treatment process by a diaphragm-metering pump. The metering pump stroke length is adjusted manually. The pulse rate is adjusted automa tically by a compound loop controller including a ratio station to match a setpoint combined chlorine residual and a set ratio of chlorine to ammonia. The aqua ammonia is stored in a bulk 5,000 gallon tank and the delivery is not attended normally by FWTP personnel except at the commencement and completion of the delivery. Operation of the aqua ammonia feed system is automatic. The receipt, storage, and handling of the subject substances are considered as part of one complete process. FEDERALLY MANDATED RMP SUBMISSION EXECUTIVE SUMMARY Page 2 of 4 3a. Worst Case Release Scenario The one ton chlorine container is the largest vessel in the chlorine system located at the Freshwater Treatment Plant, while a 150 pound cylinder is the largest chlorine vessel at the well sites and the City Pool. The Worst Case release scenario to be modeled for the one ton chlorine container assumes that the full 2,000 pounds of chlorine is released over a ten minute period resulting in a release r ate of 200 pounds per minute. The Worst Case release scenario to be modeled for the 150 pound chlorine cylinder assumes that the full 150 lbs. of chlorine is released over a ten minute period resulting in a release rate of 15 pounds per minute. The distance to the endpoint of .0087 mg/l for the Worst Case scenario is 1.3 miles. This chlorine release will extend beyond the boundaries of the stationary source. The bulk aqua ammonia tank is the largest vessel in the aqua ammonia system with a fill capacity of 5, 000 gallons, or 37,400 pounds. The Worst Case release scenario to be modeled for the aqua ammonia tank assumes that the full 37,400 pounds of aqua ammonia is released over a ten minute period resulting in a release rate of 3,740 pounds per minute. The distance to the endpoint of .14 mg/l for the Worst Case scenario is 0.9 miles. This release of aqua ammonia will extend beyond the boundaries of the stationary source. 3b. Alternative Release Scenario The Alternative Rele ase scenario for chlorine for the one ton container located at the Freshwater Treatment Plant, as well the 150 pound cylinders located at the well sites and City Pool assumes a release from a valve packing, resulting in an estimated release of no more than 2 pounds per hour. The period of release is taken to be one hour in duration, resulting in a total release quantity of 2 pounds for each regulated substance. The distance to the endpoint of .0087 mg/l for the Alternative Release scenario is 0.1 mile. This chlorine release will extend beyond the boundaries of the stationary source. The Alternative Release Scenario for aqua ammonia assumes a release from the fill hose from the delivery truck upon disconnect from the fill piping attached to the bulk storage tank. The estimated total quantity of release from the fill piping is conservatively estimated as 2 pounds over a one-hour release period. The distance to the endpoint of .14 mg/l for the Worst Case scenario is 0.1 mile. This r elease of aqua ammonia will extend beyond the boundaries of the stationary source. FEDERALLY MANDATED RMP SUBMISSION EXECUTIVE SUMMARY Page 3 of 4 3c. Administrative Controls Administrative controls to limit the distances for each reported scenario exists to restrict to a minimum the amount of chlorine and aqua ammonia released, if a release were to occur, and preferably to not have a release occur. This administrative control is inherent in the operational procedures for the chlorine and aqua ammonia systems and the training provided to the chlorine and aqua ammonia operators. 3d. Mitigation Measures Mitigation measures to limit the distances for each reported scenario exists to restrict to a minimum the amount of chlorine and aqua ammonia released, if a release were to occur, and preferably to not have a release occur. The mitigation measures are based upon the design, inspection, testing, and maintenance of the chlorine system and its related equipment and components. 4 . General Accidental Release Prevention Program and Chemical Specific Prevention Steps The facility complies with all applicable federal and state codes and regulations. There are safety meetings and safety training. The Process Safety Management (PSM) program implemented at the facility for the chlorine and aqua ammonia related activities and equipment represents one of the facility's main active commitments to an accidental release prevention program. 5. Five Year Accident History There have been no incidents involving the release of chlorine or aqua ammonia within the past five years at the facility. 6. Emergency Response Program The Emergency Response Program is based on alerting personnel at the facility of the need to evacuate the facility and await the arrival of responders from the City of Tracy Fire Department at the evacuation assembly location if a release occurs that causes the evacuation to be initiated. The San Joaquin County Office of Emergency Services incorpora tes this response into the County Area Plan for the Region 4 Local Emergency Planning Commission. FEDERALLY MANDATED RMP SUBMISSION EXECUTIVE SUMMARY Page 4 of 4 7. Planned Changes to Improve Safety There are commitments made under the Process Hazard Analysis element of the Process Safety Management (PSM) that are being implemented at this time for the next year. Current applicable codes and regulations are reviewed as part of the PSM to determine if other commitments need to be made to achieve increased operational safety for the regulated chlorine and aqua ammonia process system. These commitments will be prevention and mitigation measures for accidental releases of the regulated substances. |