Denison Municipal Utilities-Water Treatment Plant - Executive Summary |
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EXECUTIVE SUMMARY 1. Accidental release prevention and emergency response policies: In this water treatment facility, we handle chlorine that is considered hazardous by the U.S. Environmental Protection Agency (EPA). The same properties that make chlorine valuable as a disinfectant also require observance to certain safety precautions in handling chlorine to prevent unnecessary human exposure, to reduce the threat to our own personal health as well as our co-workers, and to reduce the threat to nearby members of the community. Our policy entails the intent to adhere to all applicable Federal and state rules and regulations. Safety depends upon the manner in which we handle chlorine combined with the safety devices inherent in the design of this facility. It is also dependent on safe handling procedures and the training of our personnel. Much of our emergency response program is based upon the procedures established in The Capital Controls Group Operation and Maintenance Manual pr epared for this facility. The emergency response plan includes procedures for notification of the local fire authority and notification of any potentially affected neighbors. 2. The stationary source and regulated substances handled. 7 The primary purpose of the Denison Water Treatment Facility is to clean and disinfect water to be used by the City of Denison and rural neighbors for potable purposes. Chlorine is shipped by truck to the plant in 2,000-pound cylinders (one ton). The chlorine cylinders are offloaded into the chlorine room, which is separated from the rest of the plant building. The regulated substance handled at this facility is chlorine. The maximum amount of Chlorine that can be stored at this plant is 8,000 pounds. 3. The worst-case release scenario(s) and the alternative release scenario(s), including administrative controls and mitigation measures to limit the distances for each reported scenario. 7 Worst-Case Scenario: The worst-case scenario has been defin ed as a 2,000-pound cylinder rupturing outside the chlorine building while unloading from truck. 7 The distance to the toxic endpoint of 0.0087 mg/l (8.7 mg/cubic meter) for the worst-case scenario is 2.4 miles. 7 Alternative Scenario: The alternative-case scenario has been defined as a 306-pound release from process piping or valves inside the chlorine room. The release rate was established at 10 pounds per min and occurred over a period of about 60 minutes. 7 In average weather conditions the distance to the toxic endpoint of 0.0087 mg/l (8.7 mg/cubic meter) for the alternative-case scenario is 0.39 miles. 4. The general accidental release prevention program and the specific prevention steps. This water treatment facility has worked to comply with EPA's Accidental Release Prevention Rule and with state codes and regulations. This facility was designed and constructed in accordance with NFPA-58 requirements. All of our employees have been trained in chlorine response procedure s. 5. Five-year accident history. We have not had an accidental release of chlorine 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. 6. The emergency response program. The facilities emergency response program is based upon responding to upset or malfunction conditions as described in the troubleshooting charts of the Operation and Maintenance (O&M) Manual prepared for Denison Municipal Utilities Water Treatment Facilities. Full-time Water Plant personnel are also trained on how to respond to a chlorine release. The Denison Fire Department will be called (dial 911) in the event outside emergency assistance is warranted. We have discussed this program with the Crawford County Emergency Disaster Coordinator and the Denison Fire Department. A representative of the Denison Fire Department has performed routine visits to t his plant. 7. Planned changes to improve safety. This facility recently upgraded its chlorine process to improve the safety associated with handling, storing, and using chlorine. The upgrade included switching from a system that utilized only 150 pound cylinders (that had to be handled and installed frequently) to the new system that accommodates one-ton cylinders. The new system also incorporates an early warning gas detector and alarm system. The detectors have been set to detect chlorine levels as low as 4 part per million (ppm) triggering an alarm system. The alarm system, in addition to an audible facility alarm, has the ability to place a call to the superintendent's cellular phone and a series of other emergency response phone numbers. |