OGDEN CITY WATER TREATMENT PLANT - Executive Summary |
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Executive Summary The Ogden City Water UtilityTreatment Plant is located at 900 Ogden Canyon near the base of Pine View Dam. The entire treatment complex was rehabilited, including the construction of a new pretreatment building in 1997. All operational equipment at the plant is two to three years old. The treatment plant has had a well established and effective safety program with an outstanding safety record for more than twenty five years. Ogden City Water Utility Treatment Plant is a seasonally operated water treatment plant. The normal operating season is June 1 thru September 20, but this time frame may vary depending on the demand placed on the distribution system due to an early spring or a late summer. Durring the treatment process chlorine gas is used in the plant effluent water only for disinfection before it is put into the distribution system. Chlorine gas is also used to treat our well water durring the off season before it is introduced to the distribution syste m at the treatment plant. The chlorine treated water is supplied to the residents of Ogden Canyon as well as the residents of Ogden City. A portion of this water is also sold to Bona Vista Water, a private water company. The chlorine tank storage room will handle six, one ton cylinders and is located next to the chlorine feed room. There is a Scrubber installed that will pull from both of these rooms in the event of a release. This facility is manned twenty four hours/seven days a week during the operating season and eight hours a day the rest of the year. An alarm system is connected to an audable and visual alarms on the outside of the building as well as to the computer monitoring equipment and an autodialer that will notify predetermined operators by phone of the alarm condition. In March of 1999 Ogden City sponsored a Hazwopper Training Course for all treatment plant operators, which was very beneficial for the operators as well as the City. The Instructor was Steve Carte r, a certificed Hazwopper instructor and the head of the Hazmat Response Team of the Hill Air Force Base Fire Department. In our efforts to establish a Safety Management Plan we thoroughly evaluated our operation, processes and proceedures. As a team we then developed the procedures for loading, off-loading and securing of chlorine cylinders when they arrive from the supplier. We developed and established Standard Operating Procedures for changing out empty chlorine cylinders with full ones. These procedures were put into place and we are still operating under their guidelines. Steve Carter helped us put together our action plan for chlorine leaks and what equipment was deemed necessary for handling chlorine, and especially dealing with atmospheric releases. We have some equipment and Personnel Protective Equipment for the operators to use to protect them from exposure to chlorine gas. We are in the process of purchasing additional Personal Protective Equipment and more re pair materials as well as detection and monitoring equipment for measuring the size and location of a leak. The Ogden City Fire Department Hazmat Team is designated first responder to any accidental releases of chlorine gas at the Filter Plant. They have an existing response plan but we are in the process of assisting them in updating this plan. This includes having them review our existing operation, equipment and training to give us help with additional strategies as well as keeping them familar with our facilities layout. A study was conducted in order to determine the offsite effect of chlorine gas release for two different scenarios, one being a worst-case release scenario with the criteria for this release being determined by the EPA. The other release to be an alternative release scenario and the criteria for this release to be based on a more realistic, daily operation type of accidental release. In each of the afore mentioned release scenarios the toxic endpoint of the freed chlorine gas must be defined and calculated. In conducting this drill or test the population of the affected area must be estimated to help in developing the evacuation plan. The first response to the release will be from the Ogden City Fire Department. Then if the evacuation plan is put into action the Utah Highway Patrol, Weber County Sherriffs Department and Ogden City Police Department will assist. The worst-case scenario that the EPA chose for the Ogden City Water Utility Treatment Plant was a complete gas release of a one ton chlorine cylinder. The predetermined conditions of the release are as follows; A. The release of 2,000 pounds of chlorine gas in 10 minutes. B. Incorporate the ERPG2 toxic endpoint level, calculated to be 0.9 miles. C. Wind speed of 1.5 meters per second. D. Estimated population in the affected area of 500 people. E. Atmospheric stability class F. In accordance with the tables in the Risk Management Programs 40 CFR Part 68 dispersion calculations were performed to determine the toxic endpoint of 0.9 miles. Within the calculated radius it was estimated that there would be 500 residents affected by the release. The alternative release scenario was selected to be a transfer hose failure. The predetermined conditions for this scenario are as follows; A. The release of 720 pounds of chlorine gas in 60 minutes. B. Incorporate the ERPG2 toxic endpoint level, calculated to be 0.2 miles. C. Wind speed of 3.0 meters per second. D. Estimated population in the affected area of 0 people. E. Atmospheric stability class F. In accordance with the tables in the Risk Management Programs 40CFR Part 68 dispersion calculations were performed to determine the toxic endpoint of 0.2 miles. Within the calculated radius it was estimated that there would be 0 residents affected by the release. |