Willits Water Quality Control Plant - Executive Summary |
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The City of Willits has instituted a Risk Management Program for their wastewater treatment facility, Willits Water Quality Control 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 filed as requ ired 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 The City of Willits's Water Quality Control Plant is located at 300 N. Lenore Street, Willits, CA in Mendocino County, and uses chlorine, a RS, for disinfection and dechlorination in quantities greater than the Federal threshold quantity for this RS. The facility is located in an industrial area on the northeast corner of town. There are 4 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 inside a roofed area. The chlorine is used to disinfect the wastewater effluent, and for other process uses. Pressurized chlorine within a ton container is reduced to vacuum at a vacuum regulator valve mounted directly onto the ton container's gas valve. From there, the gas under vacuum is metered through rate valves and rotameters, and drawn into water solution by the action of a submerged inductor unit using a high-speed rotating impeller to induce a vacuum. ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES It is the policy of City of Willits 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, City of Willits has gathered safety information on chlorine and on the process, equipment and procedures involving chlorine; performed a structured assessment of hazards of the process and external events which might affect the process; performed an offsite consequences analysis of defined release scenarios; established a written program for preve ntion 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 SCENARIO 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. T he "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 chlorine from the gas valve of a ton container due to an operator error during hookup, with the release secured by emergency responders by closing the gas valve after 30 minutes. ADMINISTRATIVE CONTROLS Administrative controls in effect at City of Willits which were considered to mitigate the severity of the Worst Case and Alternative Case release scenarios include City of Willits's written policies and procedures 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 ma terials 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 timely response of properly trained and equipped responders. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAMS General accidental release prevention programs instituted by City of Willits are categorized as administrative (management) programs; procedures, training, and engineering controls; and emergency response programs. City of Willits has instituted a Process Safety Management (PSM) Program meeting OSHA requirements at 29 CFR 1910.119 covering its disinfection and dechlorination process. This constitutes the general accidental release prevention program for City of Willits'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, 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 City of Willits's Emergency Response Program applicable to chlorine has been coordinated with Mendocino County Public Health Department, Environmental Health Division, the local agency responsible for hazardous materials inventory reporting and release response coordination. It consists of notification of the public agency assigned responsibility for First Response to hazardous materials release emergencies. First Responders have par ticipated with City of Willits personnel in response drills. PLANNED CHANGES TO IMPROVE SAFETY All of the improvements and mitigation measures identified in the process hazard analysis which City of Willits committed to accomplish have been completed or are in progress. It is planned to install an alarm telemetry system for chemical leaks, and to enclose the chemical storage room, within the next several months. 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. |