Patterson Pass Water Treatment Plant - Executive Summary |
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Alameda County Zone 7 Water Agency has instituted a Risk Management Program for their water treatment facility, Patterson Pass Water Treatment Plant, as required by Federal Accidental Release Prevention (ARP) Program regulations at 40 CFR Part 68. The Risk Management Program identifies the equipment, procedures, maintenance, inspection, and training associated with Regulated Substances (RS's) handled at this facility in excess of Federal threshold quantities; describes the structured assessment of hazards which was conducted to assess possible effects on employees and offsite public and environmental receptors; provides the results of an offsite consequences analysis; defines a prevention program, emergency response program, and mitigation measures to reduce the probability and magnitude of accidental releases of RS's; and establishes a schedule and responsibilities for implementation of mitigation measures and auditing of program elements. This Risk Management Plan (RMP) is being fi led as required by ARP regulations in order to report the elements of the current Risk Management Program and to describe further measures planned to mitigate or prevent accidental releases of RS's. STATIONARY SOURCE AND REGULATED SUBSTANCES HANDLED Alameda County Zone 7 Water Agency's Patterson Pass Water Treatment Plant, is located on Patterson Pass Rd. north of Greenville Rd., Livermore, CA in Alameda County, and uses chlorine, an RS, for disinfection in quantities greater than the Federal threshold quantity for this RS. The facility is located in a rural area east of Lawrence Livermore Laboratory. There are 5 full-time employees at this site. Chlorine is received in ton containers by truck, handled with an electric hoist, and stored on ton container scales and storage trunnions inside the building. The chlorine is used to control biological growth on the filters and to disinfect the treated water. Pressurized chlorine gas within the ton containers is withdrawn under pressu re and piped to a vacuum regulator valve located in the storage room where the gas pressure is reduced to vacuum. From there, the chlorine under vacuum is metered through rate valves and rotameters in chlorinators located in a separate room, and drawn into water solution by the passage of pressurized water through an injector. ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES It is the policy of Alameda County Zone 7 Water Agency that the receipt, storage and handling of chlorine at its facility be done in a manner which meets regulatory requirements and minimizes the probability and severity of accidental releases of chlorine to the atmosphere, in order to protect the health and safety of its workers, the public, and the environment. In order to accomplish this goal, Alameda County Zone 7 Water Agency has gathered safety information on chlorine and on the process, equipment and procedures involving chlorine; performed a structured assessment of hazards of the process a nd external events which might affect the process; performed an offsite consequences analysis of defined release scenarios; established a written program for prevention and mitigation of accidental releases; and established a written emergency response program coordinated with emergency response agencies. WORST CASE RELEASE SCENARIO A single "worst case" release scenario is required to be considered for each stationary source, resulting in the maximum distance to an endpoint for all toxic RS's contained on site above the threshold quantity. The worst case release scenario for toxic chemicals is defined in the ARP regulations as the release of the contents of the largest single container of RS (in this case chlorine) over a period of 10 minutes. The scenario considered the release of the contents of the largest container of chlorine on site, in this case 2,000 lb. This release scenario is not physically possible, due to the characteristics of chlorine. ALTERNATIVE CASE RELEASE SCENA RIO An "alternative case" release scenario is required to be considered for each toxic RS handled in quantities greater than the threshold quantity at the site. The "alternative case" scenario is described in the ARP regulations as a likely release resulting in offsite effects, considering administrative controls and mitigation measures in place, and is to be determined by the facility operators as part of the Process Hazard Analysis required to be performed during RMP development. The "alternative case" considered for this facility is the release of gaseous chlorine from a ton container due to an operator error during hookup, with the release secured by responders by closing the container's gas valve after 45 minutes. ADMINISTRATIVE CONTROLS Administrative controls in effect at Alameda County Zone 7 Water Agency which were considered to mitigate the severity of the Worst Case and Alternative Case release scenarios include Alameda County Zone 7 Water Agency's written policies and p rocedures for training of operators and maintenance personnel, written procedures for control of the inventory of chlorine at the facility, and policies regarding quality level of replacement materials and components for the chlorine system. MITIGATION MEASURES No mitigation measures were considered to limit the severity of the Worst Case scenario. No passive mitigation measures were considered to limit the severity of the Alternative Case scenario. Active mitigation was considered for the Alternative Case, in the form of the response of properly trained and equipped First Responders in accordance with established Hazardous Materials Incident Operational Orders. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAMS General accidental release prevention programs instituted by Alameda County Zone 7 Water Agency are categorized as administrative (management) programs; procedures, training, and engineering controls; and emergency response programs. Alameda County Zone 7 Water Agency has ins tituted a Process Safety Management (PSM) Program meeting OSHA requirements at 29 CFR 1910.119 covering its disinfection process. This constitutes the general accidental release prevention program for Alameda County Zone 7 Water Agency's operations. The program and document mangement procedures included in the PSM Program will be used as the management system for the Risk Management Program. CHEMICAL-SPECIFIC RELEASE PREVENTION STEPS Release prevention steps specific to chlorine have been identified and implemented. These include, among other things, installation of additional chlorine leak sensors at vent discharges, and creation of numerous facility-specific operation procedures with check boxes for completion of critical steps. FIVE YEAR ACCIDENT HISTORY There have been no accidents involving chlorine at this facility within the past five years resulting in injuries or offsite consequences. EMERGENCY RESPONSE PROGRAM Alameda County Zone 7 Water Agency's Emergency Response P rogram applicable to chlorine has been coordinated with the Lawrence Livermore Laboratory Fire Department, the local agency responsible for chlorine release response at the Patterson Pass WTP. It consists of notification of the public agency assigned responsibility for First Response to hazardous materials release emergencies. First Responders have participated with Alameda County Zone 7 Water Agency personnel in response drills. PLANNED CHANGES TO IMPROVE SAFETY All of the improvements and mitigation measures identified in the process hazard analysis which Alameda County Zone 7 Water Agency committed to accomplish have been completed or are in progress. Any other measures identified by employees during workplace hazard surveys, or as a result of audit activities, will be thoroughly reviewed and considered for implementation. |