Southwest Wastewater Treatment Plant - Executive Summary |
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EXECUTIVE SUMMARY We have adopted this Program in order to implement 40 C.F.R. 68, the federal requirements regulating Risk Management of Highly Hazardous Chemicals. This Program will help prevent the occurrence of, or minimize the consequences of, catastrophic releases by stating our policies and procedures for the management of process hazards in start-up, operation, inspection, maintenance and the other matters addressed in the federal standard. Our Program calls for maximum employee participation and includes all elements of the employee participation provisions of the standard. We shall, as a minimum: (1) consult with employees and their representatives on the conduct and development of the process hazard review and other elements of the risk management plan, and (2) provide to our employees and their representatives access to the process hazard review and all other information required to be developed under that standard. Accidental Release Prevention and Emergency Response Policies The City of Conroe believes that preventative maintenance is the key to minimizing the potential for accidental releases. Standard Operating Procedures (SOPs) have been reviewed and revised to enable the employees to perform their work in a safe and efficient manner. The City of Conroe has taken steps to educate and inform the operators, supervisors, and maintenance crews in the appropriate response to an accidental release. The training includes classroom training and operating procedures on the proper response to emergency situations. Stationary Source and Regulated Substances The Southwest Wastewater Treatment Plant utilizes chlorine for disinfection and sulfur dioxide for dechlorination of the treated wastewater. The maximum inventory and threshold quantities for these chemicals are shown below. All chlorine and sulfur dioxide containers are stored and utilized within separate buildings. The buildings will act as passive mitigation in the event of a release. Ch emical Maximum Inventory (lb) Threshold Quantity (lb) Chlorine 24,000 2,500 Sulfur Dioxide 20,000 5,000 Offsite Consequence Analysis The offsite consequence analysis includes a worst-case release scenario and an alternative release scenario as defined in 40 C.F.R. 68. A dense-gas dispersion model (SLAB) was used to determine endpoint distances for both scenarios. A dense-gas model is required since both chlorine and sulfur dioxide are heavier than air. The model's input parameters are summarized in the table below. SLAB Input Parameters Worst-Case Scenario Alternative Scenario Windspeed (m/s) 1.5 3 Atmospheric Stability Class F D Temperature (0 F) 104 104 Humidity (%) 50 50 Height of Release (m) 0 1 Surface Roughness 1 1 Chlorine Sulfur Dioxide End Points 0.0087 0.0078 The results of the air dispersion model are summarized in the table below along with the estimated population within the impact area. The population data was estimated using the Block Uniform Density Group Metho d in Landview III. The public and environmental receptors are listed in Section 8 of this plan. SLAB Output Results Worst-Case Scenario Alternative Scenario Chlorine Sulfur Dioxide Chlorine Sulfur Dioxide Impact Radius (miles) 1 0.9 0.45 0.4 Estimated Population with Impact Area 240 240 56 56 Accidental Release Prevention Program The City of Conroe has implemented a General Accidental Release Prevention Program to minimize releases. This Program includes: safety information on the covered chemicals, hazard reviews, operating and maintenance procedures, training, compliance audits, incident investigations, and emergency response procedures. Five-year Accident History In the last 5 years, there have not been any accidental releases from the covered process that resulted in deaths, injuries, or significant property damage on site, or known offsite deaths, injuries, evacuations, sheltering-in-place, property damage, or environmental damage. Planned Changes to Improve Safety The City of Conroe has implemented a Risk Management Plan (RMP) that meets or exceeds the requirements of 40 CFR 68. It is Conroe's philosophy to continually improve the safe working conditions of its employees to minimize accidents and reduce the potential for either an on-site or off-site release. With this in mind, Conroe is planning on incorporating many of the RMP elements into other areas of the process not covered under 40 CFR 68 to improve the overall safety of the plant. |