N18 Northeast Chlorination Station - Executive Summary

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Sacramento County Water Quality Division has instituted a Risk Management Program for their wastewater collection facility, Northeast Chlorination Station (N18), 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 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.   
Sacramento County Water Quality Division operates and maintains the regional wastewater collection system outside the City of Sacramento, and also operates and maintains the chlorination process for numerous water wells and three water treatment plants owned by other County agencies.  Its wastewater collection facility, Northeast Chlorination Station (N18), is located at 1000 River Walk Way, Sacramento, CA in Sacramento County, and uses chlorine for odor control in quantities greater than the Federal threshold quantity for this RS.  The facility is located on the site of a former wastewater treatment plant on the north bank of the American River in a residential neighborhood.  There are no full-time employees at this site.   
Operators visit the site on a regular schedule and also respond to alarm conditions.   
Chlorine is received in ton containers by truck, handled with an electric hoist, and stored trunnions inside the building.  The chlorine is used for odor control of the wastewater pumped through a force main.  Pressurized chlorine gas within a ton container is withdrawn under pressure and piped to chlorinators located in an adjacent room where the gas pressure is reduced to vacuum.  From there, the chlorine under vacuum is metered through rate valves and rotameters in the chlorinators and drawn into water solution by the passage of pressurized water through an injector. 
It is the policy of Sacramento County Water Quality Division 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, i 
n order to protect the health and safety of its workers, the public, and the environment.  In order to accomplish this goal, Sacramento County Water Quality Division 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 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 la 
rgest 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 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 in effect at Sacramento County Water Quality Division which were considered to mitigate the severity of the Worst Case and Alternative Case release scenarios include Sacramento County Water Quality Division'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 Sacramento County Water Quality Division are categorized as administrative (management) programs; procedures, training, and engineering controls; and emergency response programs. 
Sacramento County Water Quality Division has instituted a Process Safety Management (PSM) Program meeting OSHA requirements at 29 CFR 1910.119 covering its odor control process.  This constitutes the general accidental release prevention program for Sacramento County Water Quality Division'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. 
Release prevention steps specific to chlorine have been identified and implemented.  These include, among other things, installing seismic restraints for the ton containers. 
There have been n 
o accidents involving chlorine at this facility within the past five years resulting in injuries or offsite consequences. 
Sacramento County Water Quality Division's Emergency Response Program applicable to chlorine has been coordinated with Sacramento County Environmental Management Department, Hazardous Materials Division, the local agency responsible for hazardous materials inventory reporting and release response coordination.  Sacramento County Water Quality Division maintains First Responder capability with respect to chlorine releases at sites which it operates and maintains. 
All of the improvements and mitigation measures identified in the process hazard analysis which Sacramento County Water Quality Division committed to accomplish have been completed or are in progress.  Unused chlorine pressure piping is being removed, and the chlorinators are being changed to remote vacuum type.  Any other measures identified b 
y employees during workplace hazard surveys, or as a result of audit activities, will be thoroughly reviewed and considered for implementation.
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