Mattawoman Wastewater Treatment Plant - Executive Summary |
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Executive Summary Release Prevention and Response Policy In compliance with the provisions of Title 40 of the Code of Federal Regulations Part 68 and in an ongoing effort to be prepared for emergencies, The Charles County Govenment's Department of Utilities has prepared an Integrated Process Safety and Risk Management Plan for the Mattawoman Wastewater Treatment Plant located near Mason Sprongs, Maryland. It is the policy of the Department of Utilities to operate all of the water and wastewater treatment facilities within its jurisdiction in the safest and most efficient manner possible, with due regard for the health and safety of Department of Utilities employees, the Public and our environment. Stationary Source and Chemicals The Mattawoman Wastewater Treatment Plant employs gaseous chlorine for the disinfection of the wastewater. Sulfur dioxide is used to de-chlorinate the disinfected effluent prior to discharge to the environment. This is considered to be a single, continuos p rocess. The gasses are delivered, stored and drawn from one-ton containers. The Emergency Response Plan has been in existence in some form since 1980, and is coordinated with the local emergency response office. Release Scenarios The worst case scenario assumes the Environmental Protection Agency mandated elements as defined in 40 CFR 68. The basis for the calculation is the release of one ton (2000 pounds) of chlorine or sulfur dioxide (the greatest quantity held in a single vessel) during 10 minutes a 0 feet elevation and 100 degrees Fahrenheit, with an atmospheric stability of class F. An alternate scenario assumes the same quantity, a break in the gas withdrawl tubing at the tank connection, a temperature of 96 degrees Fahrenheit ( the maximum temperature, at the closest reporting station, for three years 1995 to 1997), and an atmospheric stability of class D. This simulates a spring or summer day that may occur with children occupying neighboring schools. Release Prevention T he general release prevention program is based on training, standard operating procedures and material selection. The operating personnel are trained in the proper operation, maintenance, connection-disconnection and emergency response for the chemicals employed at the Mattawoman Wastewater Treatment Plant. The two chemicals are similar enough that the operations are essentially the same. All gas-containing tubing and control devices are selected for specific compatibility and Codes and Standardes compliance. The systems are regularly and routinely inspected, and maintenance is performed as appropriate. Accident History Within the last five years and in organizational memory, there have been no accidental chlorine or sulfur dioxide releases resulting in either employee injury on-site , or with off-site consequnces. Emergency Response Program The emergency Response Program is based on the utilization of Department of Utilities Mattawoman WWTP employees and offsite Fire and Rescue p ersonnel. In the event of an unplanned release, Department of Utilities Employees will don protective respirators and attempt to control the release by closing valves on all chemical supply cylinders. If this is successful, repairs to the problem area will be made and the system will be put back in service. A release of greater magnitude and complexity will require outside assistance. In such a case, Department of Utilities employees will notify emergency communications personnel by dialling 911. The area will then be closed off and evacuated to a safe distance upwind of the release. After considerable analysis, it has been decided to reccommend a change in disinfection/dechlorination procedures. The current system employing gas chlorine and sulfur dioxide is expected to be replaced with a liquid sodium hpochlorite/sodium bisulfite system by April 1, 2000 at which time a notice of de-certification will be filed with your office. |