Evansville Water Filtration Plant - Executive Summary |
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Evansville's Water Filtration Plant utilizes chlorine as its primary means of disinfecting the City's drinking water. Chlorine, although essential for protection of public health, is classified as a hazardous chemical. Facilities, like Evansville's, which use, manufacture or store hazardous chemicals at or above various threshold quantities must meet varous Federal requirements. The recently promulgated Risk Management Program (40 CFR Parts 9 & 68) is an example of one such requirement. Effective June 21st, 1999, the goal of this Environmental Protection Agency (EPA) regulation is to protect the public and environment by minimizing or preventing the effects of catastrophic releases of toxic, reactive, fllammable or explosive chemicals. To evaluate and address potential risks to the public and environment associated with the use of chlorine, the filtration plant has formulated, conducted and maintains operations, maintenance and training procedures,in addition to hazard analysis. All of these procedures and anlaysis provide mitigation for a "worst case scenario" release. Such a release is defined by the regulation as an incident involving the release of gaseous chlorine from a one ton storage container in gaseous form over 10 minutes. With Class F atmospheric stability, and a windspeed of 1.5 m/sec the maximum distance of 1.7 miles is obtained ,using ALOHA (R) modeling, corresponding to a toxic endpoint of 0.0087 mg/l. The alternative release scenario for chlorine involves the rupture disk/relief valve not functioning properly. The scenario involves the release of 171 pounds of chlorine in a gaseous form over 10 minutes. With Class D atmospheric stability and windspeed of 1.5 m/sec the maximum distance obtained is 0.3 miles corresponding to a toxic endpoint of 0.0087 mg/l. To address this issue, the Evansville Water & Sewer Utility and EA2/SYSTEMS utilize proper safety equipement, preventative maintenance procedures and comprehensive employee training to minimize the impact of potential chlorine leaks. The Filtration Plant's inventory of chlorine is stored in a fire resistant room which also contains all chlorine equipment. Additional safety mechanisms such as pressure relief valves, excess flow devices, manual and automatic shut-offs and emergency power supply are also incorporated into the chlorine process controls. Routine maintenance and inspections ensure the proper operation of this equipment is performed according to manufacturer's guidelines. Filtration plant employees receive annual training on chlorine safety. In addition maintenance employees are given hands on training in responding to minor chlorine leaks. In more serious s ituations, local chemical companies have familiarized themselves with our system and have agreed to respond with appropriate emergency response teams and equipment. These teams would work with EA2 officials to notify local emergency response agencies and the public when necessary. Safety will remain the number one priority of the Evansville Water & Sewer Utility and EA2/SYSTEMS. By working together, we will continue to provide the public, our employees, and the environment with the technoloy, training and commitment to the public to minimize or prevent the accidental release of chlorine from the Evansville Water Filtration Plant. |