Cedar Creek Water Pollution Control Facility - Executive Summary |
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Athens-Clarke County Public Utilities Department Risk Management Plan for chlorine handling involves a unified approach that integrates technologies, procedures, and management practices to monitor potential chlorine hazards and minimize the risk of accidental chorine releases. All applicable procedures of 40 CFR 68.170 are addressed in the plan, which seeks to provide for employee safety, public health and response agency interaction. The Cedar Creek Water Pollution Control Facility (WPCF) utilizes chlorine to disinfect treated wastewater before discharge to the main stem of the Oconee River. The chlorination process includes chlorine storage cylinders, chlorination equipment, monitoring instrumentation, and a vacuum flow regulating system. Accidental release modeling was performed for the respective area to determine potential consequences associated with operating failures resulting in accidental chlorine release. The first "worst case scenario, defined by EPA, states that "t he owner or operator shall assume that the... maximum quantity in the largest vessel...is released as a gas over 10 minutes." interaction. The "alternative scenario" is defined as "more likely to occur than the worst-case release scenario." In each case, atmospheric dispersion modeling was performed to determine the distance traveled by the chlorine released before its concentration decreases to a theoretical "toxic endpoint". This is defined by the American Industrial Hygiene Association as "the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing life-threatening health effects." The residential population within a perimeter corresponding to the toxic endpoint distance was defined to estimate the population potentially affected. The worst case release scenario for the Cedar Creek WPCF involves a failure of (1) one-ton cylinder yielding a cumulative release of 2,000 lb. of ch lorine. Atmospheric dispersion modeling for this scenario was performed using the EPA's RMP Comp. The distance to toxic endpoint was determined to be 0.9 miles. The alternative release scenario involves the mechanical failure of one flexible manifold connection allowing an accidental release from a one ton cylinder of chlorine over a period of 15 minutes. The distance to endpoint was determined to be 0.1 miles under normal atmospheric conditions. The Cedar Creek WPCF has operated safely since its construction. A process history review indicates that no reportable accidental releases have occurred within the past five years. The Athens-Clarke County Risk Management Program includes the following key elements to mitigate the effects of a potential chorine release including operator training, a preventive maintenance program, process specific safety equipment and monitors, plus safe and effective standard operating procedures. Furthermore, Athens-Clarke County Public Utilities has an environmental, health and safety program with the following elements specifically supporting the safe handling of chlorine and the chlorination process including a respiratory protection (SCBA), chemical right to know, hazard review of equipment and procedures, periodic auditing and inspection, and comprehensive management. The Cedar Creek WPCF has an emergency response plan, which has been coordinated with the Athens-Clarke County Fire Department and Local Emergency Planning Committee. The plan includes emergency response drills and drill evaluations. Emergency, operational and response procedures are reviewed annually. In an effort to further enhance plant safety and readiness, the Cedar Creek WPCF will begin training to the readiness standards of 29 CFR 1910.120(q). For additional information about this plan or any of Athens-Clarke County's water treatment plants, contact Michael McEvoy by telephone at 706.613.3470 or by email at [email protected]. |