Clarence B. Walker Water Treatment Plant - Executive Summary |
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EXECUTIVE SUMMARY Clarence B. Walker Water Treatment Plant The Cartersville Water Department Risk Management Plan for the safe handling of chlorine involves a unified approach that integrates technologies, procedures, and management practices to monitor potential chlorine hazards and minimize the risk of accidental chlorine releases. The plan provides for employee safety, public health and response agency interaction. The Clarence B. Walker Water Treatment Plant utilizes chlorine to treat both the raw water from Lake Allatoona and the finished water. The chlorination process includes gaseous chlorine, chlorination equipment and process safety equipment. For the chlorination process, accidental release modeling was done to determine potential consequences associated with accidental chlorine release. The first "worst case" scenario, defined by EPA, states that the owner shall assume that the maximum quantity in the largest vessel is released as a gas over a 10-minute period. The "alt ernative scenario" is defined as more likely to occur than the "worst case" scenario. An incident history review was performed for the Walker Water Treatment Plant to determine the most likely case scenario. In each case, atmospheric dispersion modeling was performed to determine the distance traveled by the chlorine 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 human population within a perimeter corresponding to the toxic endpoint distance was determined. The "worst case" scenario for the Walker Water Treatment Plant involves the failure of a 1 ton cylinder, yielding a cumulative release of 2,000 lbs. of chlorine. When atmospheric dispersion modeling was performed for this unlikely scenario using RM P Comp software, a distance to toxic end point was determined to be 2.2 miles. The alternative release (more likely) scenario involves the mechanical failure of one pigtail connection allowing the accidental release of 160 lbs. of chlorine over a 10-minute period. RMP Comp software yields a more likely figure of 0.20 mile affected radius under normal atmospheric conditions. Within this radius, 18 receptors were identified. In support of the probability that a "worst case" accidental release will not occur, a review of process history indicates that no reportable accidental releases (greater than 10 lbs.) have occurred within the past five years. The Cartersville Water Department Risk Management Plan includes the following key elements to mitigate the effects of potential chlorine release hazards: 7 Operator training 7 Preventive Maintenance Program 7 Process specific safety equipment 7 Safe and effective standard operating procedures, written with operator participation 7 Hazard review of equipment and procedures 7 Inspection Program Further, The Cartersville Water Department has an active Safety Program with the following elements supporting the safe handling of chlorine. 7 Respiratory Protection (SCBA) Program 7 Chlorine detectors 7 Chemical Right to Know Program 7 Personal Protective Equipment Program The Walker Water Treatment Plant has a Chlorine Emergency Response Plan, which is being coordinated with the Cartersville Fire Department. Emergency response drills and facility tours will be conducted annually. |