ST. JOSEPH WATER FILTRATION PLANT - Executive Summary |
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The City of St. Joseph Water Filtration Plant (WFP) facility staff is committed to safety and is continually evaluating ways to improve safety programs. Facility staff works closely with other city and county agencies to coordinate safety and emergency response training activities. The Berrien County HAZMAT team conducts annual training exercises at the WFP. The WFP uses chlorine, a regulated substance, in 1-ton cylinders to purify drinking water for the City of St. Joseph, Michigan. The cylinders are used and stored indoors to protect them from the weather and to help limit the release rate in the unlikely event of a chlorine leak. Chlorine sensors continuously monitor the air in the rooms where chlorine is used and stored. If more than 1 ppm of chlorine is detected, an alarm sounds alerting facility personnel to a possible leak. In 1994, the WFP installed new vacuum controlled chlorine process equipment to reduce the potential for an accidental release of chlorine gas. A loss of vacuum in the process lines automatically closes the valve at the supply cylinder preventing a release of chlorine gas. The worst-case release scenario was modeled according to EPA guidelines and involved the catastrophic failure of one, full 1-ton cylinder. No mitigation measures were considered for the scenario. It is not likely that such an event would occur. EPA also requires that five alternative release scenarios be considered and that one more likely to occur than the worst-case scenario should be used in an off-site consequence analysis. The facility has no history of chlorine releases under EPA's alternative release scenarios. Chlorine is introduced into the process through a vacuum controlled regulating valve on the cylinder in service. If the vacuum is lost for any reason, the valve will automatically close preventing a release of chlorine gas. For purposes of this Risk Management Plan, it is assumed that the gasket between the vacuum controlled regulating valve and the chlorine cylinder fails, causing a release of chlorine gas. Since such a leak would occur indoors, it was estimated the release rate to the outdoors would be reduced to 55%. It is not likely that this alternatie release scenario would occur. The WFP has safely operated the present chlorine process equipment, without incident, since it was installed March 14, 1994. The facility is continually working to improve the safety of this chlorine system. Recently the chloine gas monitors were replaced with new units. The facility is covered by the Berrien County Local Emergency Planning Committee's community emergency response plan and has procedures for notifying local emergency responders in the event of an accidental release of chlorine. |