Shelbyville Water Plant - Executive Summary
The City of Shelbyville Water System accidental release prevention and emergency response program was created by system personnel and outside agencies who specialize in hazard assessment and prevention. All U.S.E.P.A. prevention program procedures are followed. The Shelbyville Water Plant has an emergency action plan, as required by OSHA, which incorporates emergency response services both inside and outside the community and complies with E.P.A. Emergency Response Program requirements. |
The Water Plant is located on Scudder Drive next to the Duck River at mile 221.9. The plant uses gaseous chlorine as a disinfectant in the water treatment process. The chlorine storage room can have a maximum of six one ton cylinders. Two of the six are hooked up to the header. An adjoining room contains the vacuum chlorinators and chlorine injectors.
The Shelbyville Water Plant provides potable water for the City of Shelbyville and the Flat Creek Water Co-Op as well as an emergency water supply
for the Bedford Utility District and the City of Wartrace.
Following is an explanation of a "Worst Case Scenario" and an "Alternative Release Scenario". As defined by EPA, the worst case scenario, states that the owner or operator shall assume that the maximum quantity in the largest vessel is released as a gas over 10 minutes due to an unspecified failure. The alternative scenario is defined as more likely to occur than the worst case release scenario. In a worst case scenario the largest vessel containing 2,000 pounds of chlorine would release its entire contents over a ten minute time period. The resulting chlorine gas cloud would travel 1.3 miles base on EPA mandated meteorological conditions of stability F atmosphere and wind speed of 1.5 meters per second. It has been estimated there are approximately 5,800 people in this 1.3 mile radius. However, only a portion of the total number of people would be affected since the gas cloud would travel in an elliptical plume extend
ing downwind from the release point.
The "Alternative Release Scenario" would involve the rupture of a flexible connection (pig tail) to the chlorine header with a release of 540 pounds of chlorine gas over a 60 minute time period. In this scenario the distance to the endpoint is .06 miles or 317 feet which is just outside the facilities boundaries.
To prevent a worst case or any release of chlorine gas, our plan is to apply available technology along with the use of proper equipment and thorough training of operating personnel. The water plant is surrounded by an earthen berm, which according to experts in the business of preventing, controlling and cleaning up toxic releases, would in fact contain the bulk of a worst case release. Automatic devices have been purchased and will be installed by the end of July 1999. These devices will close the cylinder valve when a chlorine detector recognizes a gas leak. The plant is currently equipped with visual and audible alarms to alert o
perators immediately when a chlorine gas release occurs. This facility is also staffed 24 hours a day with on going visual checks of the chlorine process.
The Shelbyville Water System is purchasing additional safety equipment and improving operator training. Since the Shelbyville Water System has coordinated with the Emergency Management Director, Shelbyville Fire Department, Shelbyville Police Department and a contracted Emergency Response Team, we feel the release prevention program is in compliance. There has been recommendations identified. These recommended actions have been evaluated and will be implemented as required.
For the five year accident history at the Shelbyville Water Plant there has been no accidental releases or personal injuries in our chlorine process.