Tete Bayou Wastewater Treatment Plant - Executive Summary
Executive Summary |
LDEQ Facility ID Number 30580. This Risk Management Plan has been developed for The City of New Iberia's Tete Bayou Waste 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 to the east of New Iberia, LA at the end of Parker St. The majority of the area surrounding the plant is used as farmland. Several residents are located to southwest of the facility along Parker and adjacent streets. The latitude and longitude of the facility was obtained from the USGS topographic map entitled New Iberia, South, LA.
The facility treats waste water from surrounding residential and commercial entities in New Iberia, LA. This treatment includes the chlorination of the water supply prior to being disposed of into Tete Bayou waterway. A continuous rate of chlorine is mixed with water in the injection room. Onc
e the chlorine is injected into the water it is diluted to an amount which is less than 1% chlorine by weight. The chlorine-water mixture is then routed to the contact chamber where the waste water is treated. The process that is subject to the RMP requirements begins with the chlorine supply (2-1 ton cylinders) and ends at the point where it is mixed with the water. The facility uses approximately one cylinder of chlorine each month. The waste water plant stores a maximum of two-one ton cylinders (4,000 lbs.) at any one time.
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 toxic endpoint. This endpoint, developed by the American Industrial Hygiene Associatio
n, is the location where minimal effects of exposure to the toxic substance are likely to occur. This distance extends from Hwy 182 at Nelson Canal Rd. to Tete Bayou just before Crochet Rd. and from Neco Town Rd at the power station to just before Hwy 86. According to a January 1999 publication of July 1, 1998 population estimates the population of New Iberia is approximately 33,850. It is estimated that the worst-case circle encompasses 25% of the population (8,463).
An alternative case or a more likely release of chlorine could occur as a result of a valve, regulator seal, or gasket leak. The plant is manned 24 hr/day and is equipped with a leak detection system that has sensors located near the chlorine cylinders. If a 1 ppm leak is detected an alarm will sound and according to facility personnel, it would take less than 1 minute for on-site personnel to respond by closing the flow valve and thus stopping the leak. Assuming the chlorine flashes to the atmosphere at a rate of
0.5 ft3/min for a maximum of 5 minutes (0.5 lbs. of chlorine) the distance to the toxic endpoint is less than 0.1 mile. The area within 0.1 mile of the facility encompasses mostly farmland and a few residents located to the south of the facility. Based on a maximum population density of 8,268 p/mi2, the population within 0.1 mile of the facility is approximately 65. However, based on information from the USGS topographic map of New Iberia and knowledge of surrounding area the actual population within the alternative-case release circle is approximately 20. This type of release is only expected to impact those persons in the immediate vicinity of the chlorine cylinders.
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 within the O & M Manuals. Records of inspections, testing,
and maintenance are also kept on file at the facility.
Written emergency response procedures are kept on file at the facility. The emergency response procedures describe actions for incidental response for facility 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 assess 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.
Current safety features installed at the facility include the leak detection system to notify employees of a chlorine leak and on-site personne
l 24 hours per day. 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.