Trahon / Big Creek Wastewater Treatment Plant - Executive Summary
Accidental Release Prevention and Emergency Response Policies |
The City of Jackson and it's wastewater treatment operator, Severn Trent Environmental Services, Inc. are dedicated to the proper use of chemicals in a manner which is safe to the environment and people. Chemical storage areas and process equipment are regularly inspected, repaired and upgraded to prevent accidental releases. Should an accidental release occur, response activities will be coordinated through the Hinds County Emergency Operations Center and the Mississippi Department of Environmental Quality. On-site plant personnel are trained to make repairs to contain small accidental releases.
Facility Description and Regulated Substances Handled
The Trahon / Big Creek Wastewater Treatment Plant treats sewage from the South Jackson and Byram areas, discharging the treated water into Big Creek and eventually into the Pearl River. The plant uses chlorine gas to disinfect the wastewater. The chlorine gas is stored
in 4 one-ton cylinders. At a given time, only 1 of the cylinders is connected on a single header.
Worst-Case Release Scenarios
EPA mandates that the Worst Case Release Scenario have a release of the entire contents of a largest single container of each regulated substance during a 10-minute period with a wind speed of 1.5 meters per second and F atmospheric stability class. Distances for releases were developed using tables listed in EPA's "RMP Guidance for Wastewater Treatment Plants." For a 1-ton release of chlorine or sulfur dioxide gas, the distance to the "Toxic Endpoint" is 1.3 miles, affecting approximately 310 residents and nearby major commercial areas and the recreational area along the Pearl River.
Alternative Release Scenarios
As recommended by the "RMP Guidance for Wastewater Treatment Plants," a wind speed of 3.0 meters per second and D atmospheric stability class were used. Gas was assumed to be released through a 1" diameter break in the supply piping. The re
lease scenarios for chlorine storage assumed the release of a single one-ton cylinder, producing a distance to the "Toxic Endpoint" of 0.2 miles, affecting no residents but affecting the nearby commercial area.
General Accidental Release Prevention Program and Prevention Steps
The plant is manned 8 hours each day including holidays with at least two operators. These operators inspect the chlorine system at least twice each shift. During the times the plant is not manned, process alarms are received at the Savanna Street Wastewater Treatment Plant, which is manned 24 hours each day, including holidays. The chlorine system has area gas monitors which trigger flashing lights and audible alarms. Maintenance personnel are immediately called in to stop small releases. The operation and maintenance of the chlorine equipment is performed in accordance with manufacturer's instructions. Operations and maintenance personnel receive regular training in the use and maintenance of the equipm
ent through monthly safety meetings, seminars provided by the equipment manufacturers and formal classes provided through the Mississippi Water and Pollution Control Operators' Association and others.
Five-Year Accident History
During the last five years, the plant has not had any releases of chlorine which resulted in death, injury, evacuations, property damage or environmental damage.
Emergency Response Program
The Trahon / Big Creek Wastewater Treatment Plant has developed an emergency response program. Once it is determined that a situation is larger than what can be handled by Plant personnel, the situation will be reported to the 911 emergency dispatcher, who will then contact the appropriate emergency response agency, such as the City Fire Department, City Police Department and Hinds County Emergency Operations Center (EOC). Through discussions in monthly Safety Meetings, through formal training conducted by the Mississippi Water and Pollution Control Operators' Associatio
n and others and through quarterly emergency drills, plant operations and maintenance personnel will be properly trained in limited emergency response. As the situation warrants, the public will be notified through the respective Public Affairs personnel at the Police, Fire and Public Works Departments and the EOC. In the event telephone contact is not possible, emergency dispatch will be conducted using the City-wide radio system.
Planned Changes to Improve Safety
Personnel training, equipment inspections and preventative maintenance will continue and be improved.