Industrial & Domestic Water Treatment Plant - Executive Summary |
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The Industrial and Domestic Water Treatment Plant (I&D) has been providing potable water since 1947. As part of the treatment process I&D uses chlorine for disinfection at a rate ranging from 500 lbs. per day to as much as 1500 lbs. per day depending on demand and source water quality. The chlorine is received by truck in 2000 lbs. containers. In 1997, I&D completed the construction and commissioning of a new chlorine storage and handling facility. Design of the new facility included the option of withdrawing the chlorine either in the liquid or gasous state. Withdrawing the chlorine in the liquid state allows the number of containers required to be open to be limited to two. By minimizing the number of open containers, the risk and magnitude of a potential release is also minimized. The facility is also equipped with multiple chlorine leak detectors and a Supervisory Control and Data Aquisition System (SCADA). The SCADA system allows plant operations personnel to monitor the s tatus of many functional and safety systems during operation. In February, 1999, I&D completed its "Program 2" - Risk Management Plan (RMP) in accordance with section 112(r) of the Clean Air Act. Although, I&D is not subject to the OSHA process safety management standard, the RMP was developed using the general structure of 29 CFR 1910.119. The RMP includes the following 14 elements: 1) Introduction, 2) Employee Involvement, 3) Process Safety Information, 4) Process Hazard Analysis, 5) Operating Procedures and Practices, 6) Employee Training, 7) Contractor Information, 8) Pre-Startup Safety, 9) Mechanical Integrity, 10) Non-routine Work Authorization, 11) Change Management, 12) Incident Investigation, 13) Emergency Preparedness, 14) Compliance Audits. It is not intended that the information provided within these elements be all-inclusive for every conceivable scenario. However, it is the intent of the plan to provide a systematic approach to defining, understanding, operating, mai ntaining, reviewing, and documenting the safe operation of the chlorination system at I&D. 3.1.3 Responsibilities The Plant Engineer has over all responsibility for insuring that the Process Safety Management Plan is being followed, reviewed, and updated. The Operations Coordinator shall be responsible for Employee Involvement, Employee Training, Incident Investigation, Emergency Preparedness, and Compliance Audits. The Operations Superintendent shall be responsible for Process Hazard Analysis, Operating Procedures and Practices, and Change Management. The Maintenance Superintendent shall be responsible for Contractors, Pre-Startup Safety, Mechanical Integrity, and Non-routine Work Authorization. The Plant Chemist shall be responsible for Process Safety Information. In addition to the responsibilities listed above, senior staff also conducts a majority of the chlorine related training and is required to respond to any leak event. Worst-Case Scenario With regard to the possibility that a catastrophic release of chlorine gas could occur at the I&D Water Treatment Plant, the "worst-case" scenario has been determined to be a complete structural failure of a single 2000 lbs. chlorine container. Although highly unlikely, the bases for this scenario is the requirement of 40 CFR '68.25 for the entire contents of the largest full container on site to completely empty its contents within a 10 minute period. The distance to the toxic endpoint of the "worst-case" release scenario has been determined to be 5.7 miles from the I&D Water Treatment Plant Alternate Release Scenario With regard to the possibility that any release of chlorine gas could occur at the I&D Water Treatment Plant, the "alternate" scenario has been determined to be a shearing off of a 1/4 inch I.D. flexible connector between the container and manifold. In accordance with the "Offsite Consequence Analysis Guidance" the maximum leak duration of 60 minutes has been used. The bases for this scenario is the requirement of 40 CFR '68.28 for the"more likely to occur than the worst-case". The distance to the toxic endpoint of the "alternate" release scenario has been determined to be 0.58 miles from the I&D Water Treatment Plant. To reduce the risk and magnitude of potential releases, I&D has established written procedures for the handling and operation of chlorination. In addition, work performed on equipment subject to cause a release requires a minimum of two personnel. Personnel are also required to wear Self Contained breathing Apparatus throughout the course of work associated with chlorination equipment. Critical work on the chlorination system has also been limited to the regular 8 hour work day to insure that sufficient personnel are immediately available should a release occur. Since 1995, only one accidental release of chlorine gas has occurred. During the construction of the new chlorine facility in 1997, the contractor failed to remove all of the air inside a new pipe line prior to pressure testing. At approximately 100 psi, the new line failed. The failure was violent enough to damage an adjacent chlorine solution line. Nearby staff closed the chlorine containers and stopped the chlorinators within approximately one minute. The concentration of chlorine in the solution line was approximately 0.02 percent by weight and the broken line released approximately 0.5 pounds of chlorine. While rushing in to assist in the repair of the line, a contractor's employee was injured by inhalation of residual chlorine vapors. The employee was taken to the hospital and released two days later. To reduce the risk of such events from occurring in the future, all work on or around the chlorine system is required to be performed under the watch of I&D plant personnel. The Risk Management Plan has been issued to the Chatham Emergency Management Agency and coordinated with the Haz-mat division of the Savannah Fire Department. In 1998, simulatio n training was conducted on site involving I&D staff, the Savannah Fire Department as well as the fire departments of several local municipalities and the Chatham Emergency Management Agency. The simulation training also involved a walk through tour and briefing for local responders of the general operation of the chlorine facility. Currently, there are no changes planned for the Risk Management Plan review and updating of the Risk Management Plan is intended to be an ongoing activity. |