O.B. Curtis Water Treatment Plant - Executive Summary

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Accidental Release Prevention and Emergency Response Policies 
The City of Jackson is 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 O.B. Curtis Water Treatment Plant withdraws water from the Ross Barnett Reservoir, treats the water and supplies the water to approximately one half of the City of Jackson.  The plant uses chlorine gas mixed in water with anhydrous ammonia gas to disinfect the water.  The chlorine gas is stored in 10 one-ton cylinders.  At a given time, 5 of the cylin 
ders are connected on a single header.  The ammonia gas is stored in two 10,000 gallon aboveground tanks.  
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 gas, the distance to the "Toxic Endpoint" is 1.3 miles, affecting approximately 3,700 residents and nearby major commercial areas, the recreational area along the Pearl River, the Ross Barnett Reservoir, the Natchez Trace Parkway and the Country Club of Jackson.  The 10,000 gallon ammonia tanks are limited to being filled to 85% of capacity due to policy of the ammonia suppliers used by the City, reducing effective capacity to 8,500 gallons.  For an 8,500 gal 
lon release of ammonia gas, the distance to the "Toxic Endpoint" is 2.6 miles, affecting approximately 18,000 residents and nearby schools, major commercial areas, the recreational area along the Pearl River, the Ross Barnett Reservoir, the Natchez Trace Parkway and the Country Club of Jackson. 
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 release scenario for chlorine storage assumed the release of all 12 one-ton cylinders, producing a distance to the "Toxic Endpoint" of 0.2 miles.  The release scenario for ammonia storage assumed the release of the contents of the one of the storage tanks (effectively 8,500 gallons), producing a distance to the "Toxic Endpoint" of 0.3 miles.  These release scenarios affect no residents, but do affect the recreational area of the 
County Club of Jackson. 
General Accidental Release Prevention Program and Prevention Steps 
The plant is manned 24 hours each day including holidays with at least two operators.  These operators inspect the chlorine and ammonia systems at least twice each shift.  The chlorine and ammonia systems have area gas monitors which trigger flashing lights and an audible alarm on the main plant computer in the Operations Room.  The chlorine and ammonia systems also have low vacuum alarms which sound on the main plant computer.  Maintenance personnel are immediately called in to stop small releases.  The operation and maintenance of the chlorine and ammonia equipment are performed in accordance with manufacturer's instructions.  Operations and maintenance personnel receive regular training in the use and maintenance of the equipment through monthly safety meetings, seminars provided by the equipment manufacturers and formal classes provided through the Mississippi Water and Pollution Control O 
perators' Association and others. 
Five-Year Accident History 
During the last five years, the plant has not had any releases of chlorine or ammonia which resulted in death, injury, evacuations, property damage or environmental damage. 
Emergency Response Program 
The O.B. Curtis Water 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 of Ridgeland Fire Department, Madison County Sheriff's 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' Association 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 Sheriff, 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.
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