Lithia Water Treatment Facility - Executive Summary
The Department |
The Hillsborough County Water Department (HCWD) has an accidental release prevention policy integrating technology, established procedures and management practices into a unified approach to risk management. The HCWD operates a number of water and wastewater treatment facilities throughout unincorporated Hillsborough County. These plants adhere to all policies and procedures of the Environmental Protection Agency (EPA) as well as the Florida Department of Community Affairs and the Florida Department of Environmental Protection.
Lithia Water Facility
The Lithia Water Treatment facility is located at 5402 LIthia Pinecrest Road, Lithia, FL 33547.
The offiste consequence analysis includes consideration of two chlorine release scenarios identified as "worst case release" and "alternative scenario". The first scenario is defined by the EPA, which states that "the owner or operator shall assume that the ... maximum quantity in the largest vessel ... is released as a gas
over ten minutes," due to an unspecified failure. The alternative scenario is identified as "more likely to occur".
The worst case scenario at Lithia Water Plant involves an unspecified failure of a single one-ton container of chlorine. The offsite consequence analysis was performed utilizing the EPA Lookup Tables and was examined for two potential releases. The EPA specified conditions for "worst case scenario" assume the release of the entire contents of the container in ten minutes, use of the one hour ERPG-2 toxic endpoint and consideration of the population residing within a full circle with radius corresponding to the toxic endpoint distance. EPA set these conditions to facilitate the performance of the offsite consequence analysis. The Water Department believes the EPA assumptions to be unrealistic because:
A. Only a fraction of the compressed liquified chlorine released to the atmosphere will flash to a vapor. The remaining liquid forms droplet aerosols. This
results in the formation of a very dense chlorine cloud consisting of vapor and liquid droplets, with dispersion characteristics significantly different than for a cloud of only chlorine gas.
B. Only the population within an elliptical plume extending downwind of the release point is potentially affected The plume area, or footprint, is approximately six percent of the area odf the full circle.
Mitigation systems to be considered at LIthia Water Plant include chlorine leak detection systems, vacuum piping and a fully enclosed chlorine storage facility. The complete enclosure reduces the potential of any toxic plume by at least 55 percent.
Release Prevention Program
The general Water Department release prevention program is based on several key elements:
A. High level of training of operations and maintenance staff
B. An aggressive preventative maintenance program
C. State of the art process and safety equipment
D. Accurate, effective
E. Hazard review of equipment and procedures
F. An in-house inspection program
Chemical specific prevention steps include the availability of self-contained breathing apparatus (SCBA) worn by operators during connections / disconnection of the chlorine supply, awareness of hazardous and toxic properties of chlorine and chlorine leak detection systems. The facility also maintains a chlorine repair kit on site.