RIVERSIDE WATER TREATMENT PLANT - Executive Summary |
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EXECUTIVE SUMMARY Macon Water Authority maintains a Risk Management Plan for safe chlorine and anhydrous ammonia handling that involves an approach that integrates technologies, procedures and management practices to monitor potential hazards and minimize the risk of accidental release. 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. Macon Water Authority utilizes chlorine to disinfect raw water pulled from the Ocmulgee River at the Riverside Water Treatment Plant and operations will begin at the Town Creek Water Treatment Plant sometime in the Fall of 1999. Once operations at Town Creek are at the needed capacity the Riverside Water Treatment Plant will be closed. Chlorine is also used at the Lower Poplar and Rocky Creek Wastewater Treatment Plants to treat wastewater before it is returned to the Ocmulgee River. In addition, the Rocky Creek Pla nt also uses Anhydrous Ammonia to assist in treating wastewater. Chlorination processes include (liquid) chlorination cylinders, chlorination equipment, and instrument room, electrical equipment, and process specific safety equipment. Ammonia processes include (liquid) Anhydrous Ammonia above ground tanks, an instrument room, electrical equipment, and process specific safety equipment. For each chlorination process 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 "the owner or operator shall assume that the. . . maximum quantity in the largest vessel...is released as a gas over 10 minutes." The "alternative scenario" is "more likely to occur than the worst-case release scenario." Macon Water Authority has no incident history. In each case, atmospheric dispersion modeling was performed to det ermine the distance traveled by the chlorine released before its concentration decrease 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 Macon Water Authority Plants involves a failure of a one-ton cylinder yielding a cumulative release of 2,000 lbs of chlorine. When atmospheric dispersion modeling for this unlikely scenario was performed using the RMP* Comp ver. 1.06 a distance to toxic .9 miles urban and 2.2 miles rural was obtained. The new Town Creek Plant presently under construction is the only plant located in a rural area. The alternative r elease (more likely) scenario for all chlorination processes involves tubing failure, bad connection, or valve failure resulting in the release of 317 lbs of chlorine. When atmospheric dispersion modeling for this scenario was performed using the RMP* comp Ver. 1.06 a distance to toxic endpoint of .1 miles urban or .1 miles rural was obtained. The worst case release scenario for anhydrous ammonia involves a failure of a 10,000 pound tank yielding a cumulative release of 10,000 pounds of ammonia, when atmospheric dispersion modeling for this unlikely scenario was performed using the RMP* comp ver. 1.06 a distance to toxic endpoint of .9 miles urban was obtained. The alternative release (more likely) scenario was performed resulting in a release of 10 pounds/minute to a toxic endpoint of .1 miles. Macon Water Authority Risk Management Program includes the following key elements to mitigate the effects of potential chlorine release hazards: Operator Training Preventive Maintenance Program Process specific safety equipment Safe and effective standard operating procedures, written with operator participation Hazard review of equipment and procedures and Auditing and inspection programs Comprehensive Management Program Macon Water Authority has an active environmental, health and safety program with the following elements specifically supporting the safe handling of chlorine and the anhydrous ammonia processes. Respirator protection (SCBA) program Chlorine detectors, ammonia shut off valves Chemical right to know program and Personal protective equipment program Macon Water Authority plants have an emergency response plan, which has been coordinated with the City of Macon and Bibb County Fire Department which is a member of the Local Emergency Planning Committee (LEPC). Emergency response dr ills, drill evaluations, and facility tours will be conducted annually, at which time emergency operation and response procedures are also reviewed. Macon water Authority takes a pro-active approach to risk management and emergency response through continuous joint training sessions between MWA employees and local response agencies. These preventive measures will provide for the continuous improvement of communications and will maintain effective procedures for the safe handling of and timely emergency response to potential chlorine or anhydrous ammonia incidents. |