City of Tyler-Southside Wastewater Treatment Plant - Executive Summary |
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Southside Wastewater Treatment Plant lies inside the city limits with boundaries delineated by a chain link fence. The site has appropriate buffers from residential areas. The Southside Wastewater Treatment Plant remains an essential facility for the City of Tyler. The plant currently treats approximately 40% of the city's wastewater. This equals out to around 5 million gallons per day. Wastewater treatment is the regulated process at this facility. This facility only stores two hazardous chemicals above the stated threshold quantity: chlorine and sulfur dioxide. Chlorine gas disinfects the water while the sulfur dioxide removes the chlorine from the water prior to discharge. The use of both chlorine and sulfur dioxide gas for wastewater treatment results in a cost-effective method for meeting state and federal surface water discharge rules and regulations. The plant safely stores 18,000 pounds of chlorine and 18,000 pounds of sulfur dioxide. The Southside WWTP chief operator edited the written operating procedures around safety and site specific information. In addition, all operators must have an operator's license from the Texas Natural Resource and Conservation Commission. All employees who handle chlorine know about the dangers of chlorine and how to safely handle the gas. Procedures for the handling of chlorine gas come from the Chlorine Institute while sulfur dioxide procedures come from the Sulfur Dioxide Handling Manual. The chief operator facilitates chemical safety by coordinating with the chlorine and sulfur dioxide gas suppliers to come out to the facility and perform a chemical safety class for the employees. The worst case release scenario models the complete release of a one ton container in ten minutes. An urban environment best describes the surrounding area. The EPA's RMP Comp Ver. 1.06 models the distance to toxic endpoint. The release has offsite impacts. They include schools, residences, and public recreat ional areas. However, such a release is unlikely due to several reasons. One is that the containers are being protected from vehicle impact and located away from busy areas. Second, operators are trained in the use of the emergency repair kits for the one ton containers. Third, the one ton containers all have relief valves that open when the temperature exceeds a set level. The alternative release scenario for chlorine models the failure of a 1 inch schedule 80 pipe which is connected to three one ton containers. The EPA's RMP Comp Ver. 1.06 models the distance to toxic endpoint. The 5/16-inch valves on each of the one ton containers limit the release rate of 80 lbs. per minute. This particular scenario closely corresponds to the actual piping setup. The offsite impacts are residences and public recreational areas. The Southside Wastewater Plant applies preventative maintenance and inspections to replace any deficient pipes or header components. The alternative release s cenario aids in planning for the emergency response. The alternative release scenario for sulfur dioxide models the same parameters as listed above for the chlorine release. Again the offsite impacts are residences and public recreation areas. The distance to toxic endpoint decreases due to the building walls containing the sulfur dioxide storage area. The Southside WWTP complies with the rules and regulations of the EPA RMP. The most important preventative measure for avoiding accidental release involves the gas feed systems. The chlorine and sulfur dioxide gas feeds via gas vacuum. The gas will cease to flow when gas piping breaks and vacuum is lost downstream of the vacuum regulator. The only potential for gas escaping is the very small amount of piping from the vacuum regulator to the ton containers. This ensures that any failure in the process equipment (chlorinators & sulfonators) will cease gas flow. This helps to eliminate chlorine and sulfur dioxide gas releases. A building with adequately designed ventilation systems and with firewalls separate the two chemical feed areas. In addition, gas detectors in the process area and storage areas will alarm personnel that a leak has occurred. All operators are trained in the written operating procedures. Preventative maintenance procedures aid in changing out wearable parts before they fail. For example, pigtails are changed out annually or at any sign of deterioration and all gaskets are replaced after any servicing. Inspections of the storage area and process area help to ensure that all valves and components are quite capable of proper shut down to isolate and stop leaks. In addition, both chemical feed systems are identically designed and adjacent to each other. This allows for streamlining safety, maintenance, and inspection procedures. The close proximity also allows for efficient inspections and increases reaction time. The SCBA's and gas detectors are tested on a routin e basis for proper functioning. The City of Tyler Southside Wastewater Treatment Plant has not had any accidental releases within the last five years that resulted in personal injury or property damage offsite or onsite. Under the City of Tyler Emergency Management Plan, response procedures exist where by emergency evacuation measures will be implemented as required. Any incidence of toxic or hazardous chemical leak or spill subject to off-site contamination will result in a 911 call by Department personnel requesting Tyler's HAZMAT Team respond to the emergency. Tyler Water Utilities complies with Federal and State HAZCOM reporting requirements, thus all chemical quantities and storage locations are on file with the Tyler Fire Department and Local Emergency Preparedness Committee (LEPC). Tyler's HAZMAT possesses mobile communication capabilities enabling them to access the LEPC's CAMEO software (located at the County Fire Marshall's Office in the Smith county Office Bu ilding). Thus, the evacuation area is clearly defined and City of Tyler Emergency Response personnel will implement evacuation procedures in accordance with the Emergency Management Plan. The State Emergency Response Commission has approved the emergency management Plan. The Southside Wastewater Treatment Plant is planning to improve safety and offsite impacts with improved safety and inspections. Facility management encourages continuing education and coordinates vendor safety training classes. Inspections and tests procedures have been outlined and new forms exist for documentation. |