Cary / Apex Water Treatment Facility - Executive Summary |
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Introduction The Town of Cary (Town) has developed a Risk Management Plan (RMP) program for control of catastrophic releases of extremely hazardous substances at its Cary/Apex Water Treatment Facility (WTF) in Apex, North Carolina. This program continues the Town's commitment to the protection of its employees and the control of the potential for such a release. To date, no such release has ever occurred at the plant. The Cary/Apex Water Treatment Facility is located on Wimberly Road in Apex. The primary purpose of the facility is to treat and disinfect raw water pumped from Jordan Lake and distribute the treated water for use in the Cary, Apex, and Morrisville areas. Currently, chlorine is used at the Cary/Apex WTF as a disinfection agent to meet Safe Drinking Water Act requirements. As part of Section 112(r) of the Clean Air Act, any facility storing more than the Threshold Quantity of 2,500 lbs. of chlorine must submit a Risk Management Plan to the Environmental Protection A gency. As part of the disinfection process the Cary/Apex WTF stores, on site, up to 16,000 lbs. of chlorine. Program Summary The RMP program supplements the procedures described in other Town of Cary documents such as general administrative guidelines and safety and health manuals. The RMP program addresses employee training, operating procedures, safe work practices, contractor safety, emergency response procedures, and a hazard review. The Town has implemented a training program with guidelines for conducting regular, structured process training for Town employees. Training record forms document the required training. The training records for all personnel associated with the covered processes appear in the training files and logbooks kept at the Cary/Apex WTF. The Town has adopted standard operating procedures (SOPs) that provide system descriptions, specifications, and operating procedures for the chlorine systems. The procedures address startup, shutdown, inspections, tem porary operation, emergency procedures, and troubleshooting. Maintenance SOPs, along with other safe work practices for handling chlorine and working in and around chlorine facilities have also been developed. Additionally, an Emergency Response Procedure documents the measures the Town will take to control process upsets and chlorine releases. A hazard review was conducted for each regulated process. The hazard review team consisted of the plant management, process operation and maintenance experts, outside process design engineers, and consultants knowledgeable in the hazard review process itself. The hazard review team used a "what-if" technique to evaluate the current procedures in place at the WTF and to generate ideas on where the procedures could be improved. To help keep the program updated and observed, detailed program management procedures have been developed. These procedures call for employee participation in control and analysis of chlorine hazards and the developme nt of precautions to prevent chlorine releases. Before modifications can be made to the chlorine system, the RMP program calls for a management of change analysis to be performed to determine what, if any, impacts the change will have on the safety of the chlorine system. Any major modifications will require a pre-startup safety review where all employees are informed of the changes to the system as well as the revised operating procedures. Finally, in the event of a release, the program requires a complete investigation and report to be completed. Accidental Release/Emergency Response To help reduce the possibility of an accidental release, the staff at the Cary/Apex WTF follows a strict preventative maintenance schedule, which has been documented as part of the RMP program. This maintenance schedule is aimed at keeping all of the equipment and materials of the chlorine system functioning properly, and identifying possible sources of system failure. In addition to the maintenanc e schedule, the hazard review team identified several areas where the standard operating procedures could be modified to reduce the possibility of a chlorine release. These modifications have since been integrated into the existing procedures. Should a release occur, there are chlorine sensors located in the sensitive areas of the plant, which will alert the staff of the release. Every employee of the Town and its contractors must remain aware of the potential for chlorine releases and disturbance of the chlorine system. When employees observe a release of chlorine or a condition that is likely to lead to a release (such as a broken chlorine solution pipe), they shall take the following actions, in a way that does not place them at increased risk. - Secure the area, if possible. This might include closing doors, closing valves, and/or warning nearby employees, - Immediately notify the inside operator or supervisory staff of the incident by any means possible, unless doing so would expose the employee to a serious hazard, - Make sure the inside operator or supervisory staff notifies emergency response agencies by dialing 911, and - Evacuate the area. Response by the Cary/Apex WTF to an actual or imminent chlorine release will occur under the direction of the local emergency response agencies. Planned Improvements It is anticipated that construction on a 16-mgd expansion to the Cary/Apex WTF will begin by the summer of 2000. As part of this upgrade, the Cary/Apex WTF will be switching from chlorine to ozone as a primary means of water disinfection. A sodium hypochlorite system will also be constructed for use as a supplemental means of disinfection and for providing a disinfectant residual in the water distribution system. The construction of the new hypochlorite system will most likely be one of the first activities undertaken as part of the upgrade. Once the hypochlorite system is constructed and tested, it will be put online as a temporar y means of primary disinfection until the ozone system is completed. At that time the gaseous chlorine system will be taken offline and all equipment and piping associated with the current chlorine system will be demolished. |