GILLETTE WASTEWATER TREATMENT FACILITY - Executive Summary

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The City of Gillette Envionmental Services Wastewater Division (WWTF) accidental release prevention program involves a unified approach that uses available technology and management policies to meet the requirements. The Gillette WWTF emergency policy involves the preparation of response plans tailored to each facility and to the emergency response available within the community . All applicable procedures of the EPA RMP are adhered to. 
 
The chlorine unit at the Gillette WWTF is a facility used to disinfect the outgoing effluent from the treatment process. This unit includes a chlorination room, which may contain four 1 ton chlorine containers and a repair kit. The unit also contains a feed room, housing the chlorinator, injection equipment, flow recorders and alarm systems. Two SCBA'S are located in the ajacent building. Wastewater operators check the unit and its' alarm systems daily and respond to any trouble alarms which may occur. 
 
The offsite consequence analysis includes the con 
sideration of two chlorine release scenarios, identified as "worst case release" and "alternative release". The first scenario is defined by EPA, which states that the owner/operator shall assume that the ..."maximum quanity in the largest vessel... is released as a gas over ten minutes due to an unspecified failure." The alternative release is defined as a "more likely to occur than the worst case." The worst case scenario at the Gillette WWTF involves a failure of the one ton container. The offsite consequence analysis is for the condition of a release of the entire amount as a gas in ten minutes, the first set of condititions pre defined by EPA. The EPA RMP OFF-SITE CONSEQUENCE ANALYSIS GUIDANCE for CHLORINE was used for this modeling.  
 
At the Gillette WWTF there would be off site consequences involving a gas release that could effect an estimated population of 7000 within a 2 mile radius. The chlorine unit is located at  the east end of the treatment process. Leak reduction, mitig 
ation and control devices that are in place are, operating procedures, chlorine gas leak detectors, and enclosed rooms for the ton containers as well as alarms in both the feed room and the container room.  
 
The alternative release scenario involves the rupture of the flexible connections (pigtails) or a lead washer leak. The same systems are in place for both passive and active mitigation, allowing us to respond to minor leaks in an efficent and timely manner.  
 
The Gillette WWTF accidential release prevention program is based on the following key elements: 
 
   High level of trainning of the operators. 
   Preventive maintenance program 
   High quality process and safety equipment 
   Use of accurate and effective operating procedures, written with the participation of the operators.  
   Hazards reviews of equipment and procedures 
   Auditing and inspection program. 
 
Chemical specific prevention steps include availability of self -contained breathing apparatus(SCBA) worn by the op 
erators durring connection /disconnection of chlorine supply, and the awareness of the hazardous and toxic properities of chlorine.  
 
No accidential releases of chlorine have occurred at this facility in the past five years.  
 
The facility has an emergency response program, which has been coordinated with the Campbell County LEPC/Fire Department. The operators have on going training in the use of SCBA's first aid and CPR, as well as equipment failure drills or related items quarterly.
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