City of Decatur - South Water Treatment Plant - Executive Summary

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The City of Decatur, South Water Treatment Plant is committed to promoting a safe operating environment for the facility, its employees, and the community. The facility continues to maintain its compliance program to meet the requirements of IL Sec. 350.280(d), "Process Safety Management of Highly Hazardous Chemicals" for the chlorination process.  Compliance with this regulation, and EPA's "Risk Management Program Rule" helps to prevent the release of chlorine from this process.  Additionally, these regulations required development of procedures to minimize releases of chlorine in the event that they do occur, and to outline appropriate emergency response steps to take in the event of a release. 
 
The City of Decatur, South Water Treatment Plant is located at 1155 South Martin Luther King Jr. Drive, Decatur, Illinois 62521.  Among the processes required for proper treatment of potable water is the chlorination process.  The chlorination process adds chlorine gas to process water to red 
uce bacteria. Chlorine is received in ton containers. The chlorination process has a separate area for storage and process activities.  The process has been designed in accordance with all local, state, and federal codes and requirements. The process has gas detection systems that alarm should the concentration of chlorine reach 1.0 parts per million. The chlorination process is maintained and operated by personnel certified by the State of Illinois as Water Treatment Plant Operators. 
 
The City of Decatur, South Water Treatment Plant has developed its worst-case release scenario utilizing EPA's "Risk Management Program Guidance for Wastewater Treatment Facilities."  This guidance document has been prepared for facilities that utilize chlorine.  The scenario assumes that a ton container has ruptured, and released its contents within a 10-minute period. The release of 2,000 pounds of chlorine has a toxic endpoint of 1.3 miles under the conditions of the scenario.  This distance is based  
on a concentration to which a person could be exposed for up to an hour without suffering irreversible health effects or other symptoms that would make it difficult for that person to escape. It should be noted that such an incident is highly improbable. Ton containers are inspected by the chemical distributor each time they are filled.  The ton containers are hydrostatically tested every five years. Loading and unloading activities are attended by trained operators. Ton containers are immediately transferred from the deliver truck into storage areas.  All container handling equipment is inspected regularly, and certified for use annually. 
 
The City of Decatur, South Water Treatment Plant has developed its alternative release scenario also utilizing EPA guidelines.  This scenario assumes that a 1/4-inch hole occurs in the system, and releases chlorine at the rate of 150 pounds per minute. For the conditions of this scenario, the toxic endpoint is 0.2 miles.  Again, such an incident is  
highly improbable, as the chlorination system has been designed, installed, and maintained to maximize the mechanical integrity of the piping system. 
 
The City of Decatur, South Water Treatment Plant Emergency Response Plan is based upon OSHA requirements for Emergency Action Plans.  The plan has been coordinated with the City of Decatur Fire Department.
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