The City of Miramar East Water Treatment Plant - Executive Summary

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EXECUTIVE SUMMARY 
 
 
1. Accidental Release Prevention and Emergency Response Policies 
 
The City of Miramars East Water Treatment Facility is required to provide disinfection to the finished water prior to distribution for public use.  Chlorine gas is used to achieve the level of disinfection required under state and federal regulations.  Chlorine is considered a toxic substance by the Environmental Protection Agency (EPA) and because quantities above the 2,500 pound threshold limit are stored on-site, a Risk Management Plan (RMP) is required.  The same properties that make chlorine valuable as a disinfectant in drinking water also make it necessary to observe certain safety precautions in handling chlorine to prevent unnecessary human exposure, to reduce the threat to on-site personnel, and to reduce the threat to nearby members of the community.  It is the policy of the City of Miramar to adhere to all applicable federal and state rules and regulations.  Safety depends on the manner i 
n which chlorine is handled, the safety devices inherent in the design of the facilities, safe handling procedures of the operators, and the training of personnel. 
 
The ability to contact outside emergency responders in the event of a chemical emergency is the basis for the City of Miramars East Water Treatment Plant emergency response program. The facility has procedures for notification of the City of Miramar Fire Department. 
 
2. The Stationary Source and Regulated Substances Handled 
 
The primary purpose of the City of Miramars East Water Treatment Plant is to provide a clean, safe, palatable drinking water that meets all the requirements of the Safe Drinking Water Act and all state requirements.  The chlorine is received via truck from Allied Chemical.  This facility has equipment for unloading the delivery trucks and storing the 2,000 pound containers.  Access to this site is restricted to authorized facility employees, management personnel, contractors and engineering consultant 
s.  Chlorine is the only substance at this facility regulated under 40 CFR Part 68, Chemical Accident Prevention Provisions.  The maximum inventory of chlorine stored at this facility is 12,000 pounds. 
 
 
3. The Worst-Case Release Scenario and the Alternative Release Scenario, Including Administrative Controls and Mitigation Measures to Limit the Distances for Each Reported Scenario.  
 
Worst-Case Scenario  Catastrophic failure of a 1-ton chlorine container due to corrosion, impact, or structural defects.  It is assumed that all 2,000 pounds of the chlorine is released as vapor, which is heavier than air, in 10-minutes.  The distance to the endpoint of 0.0087 mg/L was determined to be 1.3 miles using the EPA model RMP*Comp.  The affected area would include 10 elementary schools and residential areas. 
 
Alternative Release Scenario  Tubing failure, bad connection, or valve failure resulting in the release of chlorine gas through the 5/16-inch diameter valve body opening.  It is assumed t 
hat a 317 pound total release of chlorine gas occurs with a maximum average sustained release rate of 10.5 pounds per minute for a 60 minute duration.  The distance to endpoint of 0.0087 mg/L was determined to be 0.1 miles using the EPA model RMP*Comp. The affected area would include residential areas. 
 
Prior to acceptance of the 1-ton chlorine containers, each container is inspected for visual defects that may cause an accidental release.  The chlorination system operates under vacuum pressure and is inspected daily.  
 
4. The General Accidental Release Prevention Program and the Specific Prevention Steps. 
 
These facilities comply with EPAs Accidental Release Prevention Rule and with all applicable state codes and regulations.  These facilities were designed and are operated in accordance with federal and state codes and regulations. 
 
5. Five-Year Accident History 
 
There have not been any accidental releases of chlorine in the last five years. 
 
 
 
 
 
6. The Emergency Response Program 
 

he ability to contact outside emergency responders in the event of a chemical emergency is the basis for the City of Miramars East Water Treatment Plant emergency response program. The facility has procedures for notification of the City of Miramar Fire Department. 
 
7. Planned Changes to Improve Safety 
 
The City of Miramars East WTP is scheduled to have its gaseous chlorination system replaced by a sodium hypochlorite system within the next year.  An additional improvement includes more training for plant operators.
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