BENTON HARBOR-ST. JOSEPH JOINT WWTP - Executive Summary |
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The Benton Harbor - St. Joseph Watewater Treatment Plant (WWTP) facility staff is commited 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. As an employer the WWTP recognizes its role and responsibility to provide a safe work environment. To meet this obligation a Workplace Safety Program has been developed addressing the various aspects of the facility's operations. Through this program standards, procedures and rules governing the safe conduct of the activities and the work have been established. The desired and anticipated outcome of the Workplace Safety Program is a safe workplace for WWTP employees, the protection of the physical facility and the communty. Responsibility for the day to day administration and oversight of the Workplace Safety Program rests with the WWTP's Supervisory and Professional personnel. These individu als have been charged with the responsibility to monitor the activities of the workplace in such a manner as to achieve the highest possible level of compliance with Workplace Safety Program. Every employee of the WWTP is expected to pursue the highest professional standards of conduct in the execution of assigned activities. The safety of the employee, the employee's co-worker, along with the protection of the physical plant and the community, are considered as important as the work performed. Employment at the WWTP shall carry the expectation of a personal commitment to the completion of assigned tasks in the safest standards, procedures and rules is considered an essential part of every employee's work performance. The WWTP uses chlorine, a regulated substance, in 1-ton cyliinders to disinfect treated wastewater and uses sulfur dioxide, a regulated substance, in 1-ton cylinders to dechlorinate wastewater effluent prior to discharge to the St. Joseph River. Cylinders are stored outdoors under roof and on a concrete slab. Two cylinders of each substance are used indoors. Two safety systems on each of the chlorine and sulfur dioxide processes, provide for automatic shutdown of the processes in the unlikely event of a leak; thereby, preventing an off-site release of toxic gas. The first safety system consists of chlorine and sulfur dioxide sensor/controllers which continuously monitor air in the areas where chlorine and sulfur dioxide cylinders are attached to the process piping and feed equipment. If either chlorine or sulfur dioxide gas is detected above 0.5 ppm, the sensor/controllers automatically close valves attached to the chlorine and sulfur dioxide supply cylinders; thereby, reducing the quantity of gas available for release. Chlorine and sulfur dioxide sensor/controllers also activate an alarm to alert facility personnel to a possible leak. The second safety system on each of the chlorine and sulfur dioxide processes is vacuum based. On each pro cess two supply cylinders are connected by flexible tubing and steel pipe to a valve that opens only with the application of a vacuum and controls the flow of chlorine (sulfur dioxide) throughout the rest of the respective process. A loss of vacuum in the process feed/application lines due to a leak or other equipment malfunction will automatically close the valve for the respective system. This will minimize the quantity of gas available for release by preventing additional chlorine (sulfur dioxide) gas from reaching the process feed/application system downstream from the vacuum operated valve. The worst-case release scenario for each substance was modeled according to EPA guidelines and involved the catastrophic failure of one, full 1-ton cylinder. No mitigation measures were considered for this scenario. It is not likely that such an event would occur. EPA also requires that five alternative release scenarios be considered and the selection of the most probable scenario should be used in an off-site consequence analysis. The facility has no history of chlorine or sulfur dioxide releases under EPA's alternative release scenarios. The two safety systems described above on the chlorine process would likely prevent an off-site release of the gas. For purposes of this RMP, the most probable release scenario assumes that a gasket between the sensor controlled valve and the cylinder fails, causing a release of chlorine gas. No mitigaton measures were considered for this scenario. It is not likely that this alternative release scenario would occur. Similarly, the two safety systems described above on the sulfur dioxide process would likely prevent an off-site release of the gas. For purposes of this RMP, the most probable release scenario assumes that a gasket between the sensor controlled valve and the cylinder fails, causing a release of sulfur dioxide gas. No mitigation measures were considered for this scenario. It is not likely that this alternative r elease scenario would occur. The WWTP has safely operated the present chlorine and sulfur dioxide process equipment since it was installed in 1991. The equipment for both systems are annually inspected, serviced and, if necessary replaced by qualified equipment manufacturer's technicians to assure that safe operation of the processes continues. The facility is covered by the Berrien County Local Emergency Planning Committee's (LEPC) community emergency response plan and has procedures for notifying local emergency responders in the event of an accidental release of chlorine or sulfur dioxide. |