Worthington Water Treatment Facility - Executive Summary |
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Programs for chlorine release prevention and emergency response are reviewed and updated by the MMUA (Minnesota Municipal Utilities Association) annually. Chlorine is the most hazardous substance that we handle and any release will be called in to the Nobles County Emergency Management Office for public safety. The Wate Filtration Plant uses chlorine for an oxidating agent as well as a disinfectant. The chlorine is contained in metal cylinders, which hold 2000 lbs. each. The maximum number of containers on site will be five. The cylinders are housed in a chlorine room, which is attached to the filtration plant. A window between the filter plant and the chlorine room allows us visual inspection of the chlorine containers and feed apparatus. A worst case scenario would involve a one ton cylinder being dropped during handling and rupturing, causing the contents to spill onto the ground, which would immediately start vaporizing. The cloud of chlorine gas would move with the wind close to the ground as it is heavier than air. If the wind was from a southerly direction, the gas would envelop nearly the entire community of Worthington, necessitating the evacuation of nearly 10,000 people. A call to the county's emergency operations coordinator would set the emergency response program into effect. An alternate release scenario would involve chlorine gas coming from a half inch hole in a section of feeder tubing in the chlorine room. In this case, the gas would set off a chlorine gas monitor with an audio alarm as well as a visual alarm. The monitor is also hooked to an automatic dialer, which would alert the operator on call. All employees of the Water Department are being trained on the use of PPE (personal protective equipment) which would be used in this scenario. At a minimum, three employees would work on the problem with two of the three being equipped with NISOH approved, self contained breathing apparatus and they will evaluate th e situation and correct if possible. The other employee will be on the outside of the chlorine room ready to call for help if necessary. In this scenario, the wrench on the tank valve would be used to close the valve and stop the release of gas. The scenario described would be termed an incidental response and handled by Water Department personnel. The toxic end-point would be reached at about 0.3 of a mile from the plant and would involve little offsite impact. General accidental release prevention at the site includes a warning system with a chlorine gas detector that is mounted in the plant on an adjacent wall to the chlorine room. All connections and piping are checked on a regular basis. Training is required of all employees on the handling of chlorine and the safety programs involved with chlorine. There has been no accidental releases of chlorine at the water filtration plant up to the present time. The emergency response program involves coordination with the Nobles County Emergency Operation Plan during a chlorine release. The Nobles County Emergency Management coordinator would direct required responses of the various units of govermnent involved. Water Department personnel are trained and equipped to handle only incidental responses, gasket failure, valve leakage, etc. The plant has an emergency response plan on site for step by step procedures that will be taken depending on the severity (level one, two, or three) of the release. The improvement of the safety programs at the plant will be continually reviewed and any new control equipment will be looked at and evaluated. Training will be an ongoing program involving personal protective equipment (PPE), classroom training and policy reviews. |