Anderson Wastewater Treatment Plant - Executive Summary

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The City of Anderson has instituted a Risk Management Program for their wastewater treatment facility, Anderson Wastewater 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 filed as req 
uired 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.   
The City of Anderson's Wastewater Treatment Plant is located at 3701 Rupert Rd., Anderson, CA in Shasta County, and uses chlorine for disinfection in quantities greater than the Federal threshold quantity for this RS.  The facility is located on the west bank of the Sacramento River next to a public park.  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 trunnion sets inside the building.  The chlorine is used for odor control of the influent wastewater, to disinfect the wastewater effluent, and for other process uses.   Pressurized gas within a ton container is reduced to vacuum at a vacuum regulator valve mounted directly onto t 
he ton container's gas valve.  From there, the gas 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. 
It is the policy of the City of Anderson 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 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, the City of Anderson 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; esta 
blished a written program for prevention and mitigation of releases; and established a written emergency response program coordinated with emergency response agencies. 
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. 
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 liquid chlorine from a pinhole in one of the fusible plugs on a received ton container, due to a supplier error or damage in transit, with the release secured by application of a Type "B" Ton Container Repair Kit fixture after 20 minutes. 
Administrative controls in effect at the City of Anderson which were considered to mitigate the severity of the Worst Case and Alternative Case release scenarios include the City of Anderson'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 materials and components for the chlorine system. 
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 personnel following established emergency response procedures. 
General accidental release prevention programs instituted by the City of Anderson are categorized as administrative (management) programs; procedures, training, and engineering controls; and emergency response programs. 
The City of Anderson has instituted a Process Safety Management (PSM) Program meeting OSHA requirements at 29 CFR 1910.119 covering its disinfection process.  This constitutes the gen 
eral accidental release prevention program for the City of Anderson's operations.  The program and document management procedures included in the PSM Program will be used as the management system for the Risk Management Program. 
Release prevention steps specific to chlorine have been identified and implemented.  These include, among other things, installing seismic tie-down straps for ton containers and seismic restraints for ton container scales, and creation of numerous facility-specific operation procedures with check boxes for completion of critical steps. 
There have been no accidents involving chlorine at this facility within the past five years resulting in injuries or offsite consequences. 
The City of Anderson's Emergency Response Program applicable to chlorine has been coordinated with Shasta County Department of Environmental Health, 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 and evacuation of persons on site to designated assembly areas upwind of the released gas.  First Responders have participated with City of Anderson personnel in response drills. 
All of the improvements and mitigation measures identified in the process hazard analysis which the City of Anderson 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.
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