Luling Oxidation Pond - Executive Summary
Executive Summary |
St. Charles Parish Department of Wastewater
ACCIDENTAL RELEASE PREVENTION and EMERGENCY RESPONSE POLICIES
Accidental Release Prevention: St. Charles Parish and the Department of Wastewater are committed to the safe operation of the Luling Oxidation Pond. Continuous review of standard operating procedures (SOPs) and mechanical integrity programs help to ensure that the chlorine system is operated and maintained in a safe manner. The Department provides formal training for all operators and maintenance personnel focusing on chlorine safety. Annual audits are conducted by representataives of the Parish's Emergency Operations Center (EOC) to familiarize themselves with the chlorine system.
Emergency Response Policies: Operators at the Luling Oxidation Pond will not respond to leaks beyond their ability to control through the use of valves. In the event of such a release, plant personnel will notify EOC and evacuate the area. EOC will establish a safe perimeter and b
egin public notification. EOC will handle all emergency procedures and evacuation. The facility is included in the Local Emergency Planning Committee's community emergency response plan.
THE WESTBANK WASTEWATER TREATMENT PLANT
The Luling Oxidation Pond (Pond) is a 2.2 million gallons per day oxidation pond that serves the Luling area of St. Charles Parish. Treated effluent from the plant is discharged to the George Cousins Canal. Disinfection of the effluent is accomplished by injecting chlorine into the effluent box. Chlorine is stored in a maximum of twelve-one ton cylinders. The Pond is owned and operated by the Parish. It is located in the Parish's wetlands which surround it on all sides and can only be accessed via a single road.
WORST CASE RELEASE
The worst case release at the West Bank WWTP, the St. Charles Parish EOC Coordinator, involves the release of the entire contents of 6 one-ton cylinders over a one minute period equating to a 200 lb/sec release rate. Under F Class a
tmospheric stability (very stable atmosphere), 75 F, 0.40 m/s wind speed (3 meters), in an urban environment, it is expected that the toxic endpoint, 0.5 ppm of the chlorine plume will be reached >6.0 miles downwind from the point of release. This value was determined by using the attached summary developed by EOC. The attached information provides specific details of the chlorine release.
ALTERNATE RELEASE SCENARIO
The scenario modeled under the alternate release scenario was a leak from a whip connecting the cylinder to a distribution header. Chlorine is expected to leak through a hole of approximately 0.4 inches in area and continue for 1 hour (maximum). Using the attached data supplied by EOC, this scenario produced an endpoint of 0.5 ppm at a total distance of 1055 yards. No active or passive mitigation measures were assumed to mitigate the release.
THE GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM and CHLORINE RELEASE PREVENTION
The critical elements that the Parish uses
to prevent accidental releases are the recently reviewed and updated Standard Operating Procedures (SOPs), Mechanical Integrity Program, and Training Program. These three programs have a significant impact in the continued safe operation of the chlorine system.
THE FIVE-YEAR ACCIDENT HISTORY
There have been no accidents, as defined in 40 CFR 68.42, at the Pond in the last five (5) years.
THE EMERGENCY RESPONSE PROGRAM
As descriped above, personnel at the Pond will not act as responders to uncontrollable releases of chlorine. Rather, the Emergency Action Plan will be implemented which notifies the Parish's EOC .EOC will provide support and technical assistance to contain chlorine releases beyond the ability of Parish personnel. The Pond is included in the community emergency response plan for the Parish of St. Charles.
PLANNED CHANGES TO IMPROVE SAFETY
The Parish intends to convert the current pressure system to a vacuum system that will mitigate the total potential quantity of
chlorine released from the Pond under the alternate release scenario. Additionally, the Parish is investigating the feasibility of ultraviolet radiation as a disinfection source in lieu of chlorine. Also, the visible alarm will be upgraded to include an audible alarm. These alarms will be included in a telemetry system that will be monitored 24 hours per day, 7 days per week by a remote operator.