City of Port Neches Water Treatment Plant - Executive Summary |
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1. Purpose: The purpose of the Risk Management Plan contained herein is to detect and prevent or minimize accidental releases of chlorine from the Water Treatment Plant, and to provide a prompt emergency response to any such releases in order to protect human health and the environment. 2. General: The City of Port Neches owns and operates a surface water treatment plant located on the corner of Park Street and Avenue D in Port Neches, Texas (No official US Post Office address is available). The plant uses chlorine and anhydrous ammonia (and other chemicals not listed in 40 CFR 68.130) in the water treatment process. The Risk Management Program for the plant considers toxic release scenarios only. There are no flammables stored or used on-site that can be considered a regulated substance. Chlorine Chlorine is delivered in DOT 106A500X 1-ton containers from a local chemical supplier. The maximum quantity of chlorine present at any given time at the plant is 12,000 pounds. Th e 1-ton containers are stored in an enclosed structure. Chlorine is included in the City's Risk Management Program because the on-site quantity exceeds the amount listed in 40 CFR 68.130. The maximum quantity of chlorine used on-line in the chemical feed process is 4,000 pounds. It is the policy of the City of Port to have a maximum of two 1-ton chlorine containers connected to the chemical feed process at any given time. Anhydrous Ammonia A local chemical supplier delivers anhydrous ammonia to an on-site 500-gallon tank. The maximum quantity of anhydrous ammonia stored on-site at any given time is 2,335 pounds. Anhydrous ammonia is not included in the City's Risk Management Program because the on-site quantity does not exceed the amount listed in 40 CFR 68.130. 3. Accidental release prevention and emergency response policies: The City of Port Neches Water Treatment Plant uses chlorine in the treatment process, which is considered hazardous by the EPA. The same properties that make chlorine an effective chemical for disinfecting raw surface water also make it necessary to exercise certain precautions in the handling of chlorine to prevent unnecessary human exposure. The Water Treatment Plant operators use chlorine-handling procedures that are designed to reduce the threat to themselves and their co-workers, and to reduce the threat to members of the surrounding community. It is the policy of the City of Port Neches to adhere to all applicable Federal and State rules and regulations. Safety is dependent on the manner in which chlorine is handled, the design of the chlorine feed process, and the training of the operators in safe handling procedures. The emergency response program for the Water Treatment Plant is based on the Chlorine Institute's EMERGENCY RESPONSE PLANS FOR CHLORINE FACILITIES, Edition 4, November 1995. The emergency response plan includes procedures for notification of the Port Neches Fire Department (PNFD), and any potentially affe cted neighbors within the affected toxic endpoint radius calculated by the RMP*Comp software and the alternative release scenario published in section 4.5.2 of the Chlorine Institute's ESTIMATING THE AREA AFFECTED BY A CHLORINE RELEASE, Edition 3, April 1998. 4. The stationary source and regulated substances handled: The purpose of the Port Neches Water Treatment Plant is to provide a safe drinking water supply to the citizens of the City of Port Neches. Chlorine is used in the treatment process to disinfect surface water supplied by the Lower Neches Valley Authority. Chlorine gas is fed from 1-ton containers to a manifold, then through a vacuum operated gas dispensing system, then through a PVC piping system, and finally through a metering system at the point it is ejected to the water treatment process. The chlorine is delivered in Department of Transportation (DOT 106A500X) approved 1-ton containers for use in the water treatment process. The facility has equipment for moving the 1-ton containers between a holding rack and the scales where the containers are tied-in to the chemical feed process. The supplier loads and off-loads containers using equipment on the bed of the delivery truck. The only substance at this facility that exceeds the limits listed in 40 CFR 60.130 is chlorine. The maximum amount of chlorine stored at this plant is 12,000 pounds, that is six 1-ton containers at any given time. 5. The worst-case release scenario and the alternative release scenario, including administrative controls and mitigation measures to limit the distance for each reported scenario: Worst-Case Scenario - Failure of a 1-ton container filled to capacity is considered the worst-case scenario. The release is considered to occur over a ten-minute period. Passive mitigation is also considered because the containers are kept in an enclosed storage facility. The worst-case scenario is modeled after American Water Works Association (AWWA) Research Foundation's pu blication COMPLIANCE GUIDANCE AND MODEL RISK MANAGEMENT PROGRAM FOR WATER TREATMENT PLANTS, 1998. Scenario CLW-2, Worst-Case Scenario for 1-ton Chlorine Container: Catastrophic failure due to corrosion, impact or construction defects is used in this Risk Management Program. It is assumed that the entire contents of a 1-ton container are released and will potentially affect a radius of 0.9 miles (4,800 feet) according to the EPA's RMP Comp dispersion model. The concentration at the toxic endpoint of 0.9 miles is considered 0.0087 mg/L as listed in Appendix A of 40 CFR 68. Alternative Scenario - Failure of a ton container valve or failure of the 1/4-inch "pigtail" connection to the manifold is considered the most likely alternative release scenario. The alternative release is modeled after the scenario presented in section 4.5.2 of the Chlorine Institute's ESTIMATING THE AREA AFFECTED BY A CHLORINE RELEASE, Edition 3, April 1998. Trained PNFD and Water Treatment Plant personnel est imate active mitigation to occur within one hour of commencement of the release. The distance to the toxic endpoint is considered to be less than 0.1 miles (<530 feet). This release has the possibility of extending beyond the facility boundary and requires implementation of the Emergency Response Plan and notification of the Local Emergency Planning Committee. 6. The general accidental release prevention program and the specific prevention steps: The City of Port Neches Water Treatment Plant complies with the EPA's Chemical Accident Prevention Provisions and with all applicable state codes and regulations. The facility was designed and constructed in accordance with TNRCC regulations, AWWA guidelines, and according to sound engineering principles. Water Treatment Plant operators have been trained using Texas Water Utilities Association (TWUA) programs that fall under the rules and regulations of the TNRCC. Operators have also been trained on-the-job using the Chlorine Institute 's EMERGENCY RESPONSE PLANS FOR CHLORINE FACILITIES, Edition 4, November 1995; FIRST AID AND MEDICAL MANAGEMENT OF CHLORINE EXPOSURES, Edition 5, May 1993; and current O & M Manual procedures for dealing with a chlorine release. 7. Five-year accident history: There were no reportable accidents in the last five years. 8. The emergency response program: The City of Port Neches Water Treatment Plant's Emergency Response Program is based on the Chlorine Institute's EMERGENCY RESPONSE PLANS FOR CHLORINE FACILITIES, Edition 4, November 1995. The program was developed with recommendations and guidance of the PNFD. The Jefferson County Emergency Planning Committee has been notified of the specific scenarios and responses that the plan covers. A planning meeting between the treatment plant supervisors and the PNFD was held in June 1999 to implement the current plan. 9. Planned changes to improve safety: The chemical feed system was designed in 1994 and constructed in 1995. The des ign and construction were approved by the TNRCC. The hazard assessment, prevention program, and emergency response plan were reviewed and updated before submittal of the current Risk Management Plan. No changes in operating procedures or processes are necessary at this time. |