Union Hills Water Treatment Plant - Executive Summary

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Executive Summary 
    Union Hills Water Treatment Plant (WTP) is one of the many facilities owned and operated by the City of Phoenix.  Union Hills WTP has prepared a Risk Management Plan (RMP) in accordance with the EPA and OSHA regulatory requirements.  A brief overview of the RMP and the associated policies at Union Hills WTP is described below. 
Prevention and Response Policies 
    The City takes an active role in preventing accidental releases by ensuring that its employees are properly trained in the safe operation of covered processes and the safe handling of treatment chemicals.  The City has also established and maintains procedures for emergency notification and response.  These are reviewed with employees on a periodic basis and revised to accommodate changes in staffing when they occur.  To increase employee safety and awareness, the City: 
7 maintains up-to-date safety information and operating procedures, 
7 performs regular preventative maintenance, 
7 provides periodic r 
efresher training on safe handling of chemicals, and 
7 conducts quarterly safety drills. 
Facility Description and Regulated Substances 
    Union Hills WTP utilizes surface water supplies to produce potable water through a series of physical and chemical treatment operations. 
    The regulated substance handled at Union Hills WTP is chlorine.  The chlorine is stored in 17-ton tankers, with a maximum of two tankers on site.  
Release Scenarios 
    Worst-case and alternative release scenarios have been determined after careful review of the regulation and consideration of the storage vessel configuration at the facility.  The EPA's software program RMP*Comp was used to model both release scenarios and determine the radius of impact. 
    In the worst-case release scenario, the regulation clearly states the release quantity shall be the contents of the single largest vessel of the covered process chemical. Therefore, the scenario assumed a complete release of chlorine from one 17-ton  
tanker (34,000 lbs) inside the chlorine storage building.  Per the regulation, no active mitigation measures, such as a scrubber, could be considered.  The passive mitigation effect of the chlorine storage building reduces the amount of chlorine released to the atmosphere by 55% (from 34,000 lbs to 18,700 lbs). 
    For the alternative release scenario, the assumptions were that (a) a failure occurred in the feed line, (b) 7,000 lbs of chlorine were released over a 60-minute period, (c) the release occurred in the chlorine storage building, and (d) the scrubber did not work.  The passive mitigation effect of the chlorine storage building reduces the amount of chlorine released to the atmosphere by 55% (from 7,000 lbs to 3,840 lbs). 
Prevention Steps for Chlorine 
    The prevention program fulfills the requirements of the OSHA Process Safety Management (PSM) rule and the EPA RMP rule, and includes: 
7 formal and on-the-job training,  
7 written operating procedures, and 
7 a process equi 
pment preventive maintenance program.   
    The primary means of mitigating an accidental chlorine release at Union Hills WTP is the installation of a chemical scrubber for the chlorine building.  The scrubber is maintained on a regular basis to ensure proper operation if needed during a chlorine release. 
Accident History 
    There has been no accidental release of the covered chemical in the past five years. 
Emergency Response Program 
    This facility has established and maintains an emergency response program that is coordinated with local response agencies. The goals of the program are to protect on-site employees from the hazardous effects of the releases and to minimize the effects of releases on the general public.  The program is routinely reviewed and updated to reflect personnel and regulatory changes. 
Planned Changes for Improved Safety 
    Ideas for changes to improve safety are actively sought from employees.  Employee meetings that focus on safety issues are held r 
egularly at the facility.  Employees are encouraged and trained to recognize hazards and present ideas to eliminate them or to minimize the potential consequences of those hazards. 
    During the development of this RMP document, a process hazard analysis of the chlorine system was conducted with key employees to fulfill the prevention program requirements.  During these sessions, recommendations were made for the purpose of improving safety and preventing accidental chemical releases.  Each recommendation will be or has been considered for implementation.  Though not all recommendations may be implemented, the exercise provided all affected employees with a heightened awareness of safety issues related to the covered processes.
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