The City of Bunkie Water Treatment Plant - Executive Summary |
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Executive Summary LDEQ Facility ID Number 27697. This Risk Management Plan has been developed for The City of Bunkie's Water Treatment Plant in accordance with 40 CFR part 68. This facility is subject to the requirements of this program due to the usage and storage of chlorine in an amount greater than 2,500 lbs. The facility is located within the city limits of Bunkie, LA on the corner of Rose St. and Mable St. The area surrounding the plant is residential. The latitude and longitude of the facility was obtained using a hand-held Garmin 75 GPS device with an accuracy of +/- 100 meters. The facility is easily visible on the USGS quadrangle map entitled Bunkie, LA. The facility treats and supplies water to residential and commercial entities located in Bunkie. This treatment includes the chlorination of the water supply prior to being distributed throughout the city. The rate of chlorine injected into the water is automatically regulated and varies based on the current needs. Once the chlorine is injected into the water it is diluted to an amount which is less than 1% chlorine by weight. Therefore, the process that is subject to the RMP requirements begins with the chlorine supply (2-1 ton cylinders) and ends at the point of injection into the water. The facility purchases the pre-filled chlorine cylinders from Harcros Chemicals, Inc. approximately once every two months. The water plant stores a maximum of two-one ton cylinders (4,000 lbs.) at any one time. The tanks are under a fiberglass cover that is open on all sides. The entire facility is enclosed within a chain-linked fence. The worst-case release scenario would involve the release of the greatest amount from a single vessel as required by 40 CFR part 68.25 (b)-Determination of worst-case release quantity. This type of release may occur as a result of catastrophic natural or other unforeseen disaster. A release of 2,000 lbs. for a duration of 10 minutes results in a 1.3 mile distance to the t oxic endpoint. This endpoint is the location where minimal effects of exposure to the toxic substance are likely to occur as determined by the American Industrial Hygiene Association. This distance encompasses the entire city of Bunkie from Hwy 1177 (Shirley Rd.) at Second Union Church to US Hwy 71 at Bayou Huffpower and from E. Oak St. just after Christian Cemetery to the Turner Canal. According to a January 1999 publication of July 1, 1998 population estimates the population of Bunkie is approximately 5,075. An alternative case or a more likely release of chlorine could occur as a result of a valve, regulator seal, or gasket leak, or from a small amount of liquefied chlorine being trapped between the valve of the cylinder and the equipment line attachment. The plant is equipped with a leak detection system with sensors located near the chlorine cylinders and in the injection room. If a 1 ppm leak is detected an alarm will sound and an automatic call to the fire department and to the employee on duty will be made. The injection system is also equipped with a device that automatically closes the valves at the cylinders if a loss in pressure within the injection line is detected. According to facility personnel, it would take less than 1 minute to respond by closing the flow valve and thus stopping the leak if employees are on-site at the time of the leak detection. If the alarm sounds at a time when no personnel are on-site, it would take approximately 15 minutes for personnel to arrive on-site and stop the leak. Assuming the chlorine flashes to the atmosphere at a rate of 0.5 ft3/min (1.5 lbs. of chlorine) for a maximum of 15 minutes the distance to the toxic endpoint is less than 0.1 mile. The area within 0.1 mile of the facility extends along Rose St. from Knoll Ave. to just before Lexington Ave. and from just before McArthur Dr. to St. John St. Based on a maximum population density of 8,268 p/mi2, the population within 0.1 mile of the facility is a pproximately 65. This type of release is expected to impact only those persons in the immediate vicinity of the chlorine cylinders. There are no environmental receptors within this area. The facility has not experienced a release which caused on or off site injury, death or property damage within the past five years. Facility employees are properly trained in the operating and maintenance procedures. These procedures are kept on-site in the O & M Manuals developed by Domingue-Szabo & Associates, Inc. Records of inspections, testing, and maintenance are also kept on file at the facility. In addition to the leak detection system the process is also equipped with an automatic shut-off system. If a change in pressure within the injection line is detected the system automatically closes the flow valve at the chlorine tank. Written emergency response procedures are kept on file at the facility. The emergency response procedures describe actions for incidental response for facil ity personnel in the event of a relatively small leak or release that does not pose an immediate safety or health hazard. If incidental response activities do not halt the release or the release poses an immediate safety or health hazard, specially trained response personnel are contacted to take over response activities. In the event of a chlorine leak or release, employees are instructed to asses the situation and to determine if it is safe to discontinue the leak without the help of emergency responders. If there are any doubts as to the safety of the release, the employees are to initiate the written notification procedures. Details to these procedures are found in Section 7.0 of this manual. Current safety features at the facility include a leak detection system which activates the phone notification system and an automatic shut-off feature. Inspections of the process and associated equipment are conducted on a regular basis to avoid failure and detect normal wear and tear of equipment parts. Also, the fiberglass cover protects the chlorine cylinders from the heating effects of being in direct sunlight. |