Bammel U.D. Wastewater Treatment Plant - Executive Summary
BAMMEL UTILITY DISTRICT |
WASTEWATER TREATMENT PLANT
SOURCE AND PROCESS DESCRIPTION: Bammel Utility District (Bammel) owns, manages, and operates a Wastewater Treatment Plant (WWTP) located at 17402 Falling Creek. The design capacity for the WWTP is 2,000,000 gallons per day (gpd) average daily flow, and 8,000,000 gpd peak hydraulic flow. The influent that comes in to the WWTP is subject to several different treatment processes before it is discharged in to Cypress Creek. One of the last treatment processes is disinfecting the effluent just before it is discharged. Gaseous chlorine is used to disinfect the effluent. Because chlorine is used, the WWTP is responsible for submitting a Risk Management Plan (RMP) to the Environmental Protection Agency (EPA). EPA published 40 CFR 68 on June 20
, 1996. In this rule, there are 77 regulated toxic chemicals and 63 regulated flammables. All of these flammables and toxic substances have a certain threshold quantity. Gaseous chlorine, for instance, has a threshold quantity of 2,500 lb. The WWTP has a maximum of 4,000 lb. of gaseous chlorine on site under certain conditions. Chlorine is the only regulated toxic chemical at the WWTP with a higher amount than the threshold quantity.
CONSEQUENCES OF FAILURE TO CONTROL THE HAZARDS: According to EPA, a worst case scenario is assumed when a one (1) ton cylinder has a leak such that its duration lasts for ten (10) minutes. A one (1) ton cylinder (2,000 lb.) will have a release rate of 200 lb. per minute for ten (10) minutes. A chlorine gas leak such as this would create a toxic gas cloud that has the potential to effect approximately 11,000 people within a 1.3 mile radius. Depending on how much chlorine is inhaled, effects could range from as little as a slight irritation to
the eyes, skin, or lungs to possibly inhaling a large enough dose to prove fatal
EXPLANATION OF HOW RELEASES ARE PREVENTED: Bammel UD has charged its operator, Water District Managment Co. (WDM), with the duty of operating a safe WWTP. WDM uses several methods in order to safely operate Bammel's WWTP. They must practice good preventive maintenance, timely corrective maintenance, and hire/train employees that are knowledgeable in the safe handling of gaseous chlorine and gaseous chlorine equipment.
In addition to properly selected, handled, and maintained equipment, the facility includes a comprehensive chlorine detection and alarm system. The system consists of low and high gas concentration detectors. The low concentration detector notifies the operator by an automatic alarm telephone dialer. After being alerted by the autodialer, the operator will assess the situation and do what is necessary to prevent a minor leak from graduating to a major leak. The operator will evacua
te the premises if a high level alarm is detected, and allow the Klein Volunteer Fire Department to handle the situation.
STEPS TAKEN TO ADDRESS HAZARDS: Recommendations are generated for improving operations and reducing risks on an ongoing basis. The contractor that performs the semi annual preventive maintenance is continually asked for recommendations to improve the safety of the installation. All employees are required to attend training which includes safety reviews and newest trends in equipment operation. The facility engineer is called in as needed to review the safety of the chlorine gas feed system along with the manufacturers representatives. The chemical supplier also has an ongoing program of inspecting its cylinders for problems before they occur. Each cylinder is inspected prior to being refilled with gas.
RESPONSE ACTION IN THE EVENT OF A RELEASE: If a vapor cloud is suspected, it is recommended that you immediately go indoors (do not try to outrun the
cloud as you may not be running away from it, but instead, right in to it), turn off the air conditioning system, and stuff wet towels in all cracks such as under doors and around windows.
Signs with emergency phone numbers are posted on the gate of the WWTP. It may be a good idea to write these phone numbers down and keep them with other emergency phone numbers you may already have. After you have found refuge indoors, ensure that the Klein Volunteer Fire Department has been notified at (281) 251-0101. Do not return outdoors until you have received an all clear signal from the fire department.