Waldron ARKANSAS Water Treatment Plant - Executive Summary |
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CITY OF WALDRON,ARKANSAS RISK MANAGEMENT PROGRAM EXECUTIVE SUMMARY The City of Waldron, Arkansas owns and operates a potable water treatment plant that uses liquid chlorine as a disinfectant. Chlorine is one of the regulated substances listed in the federal regulations (40CFRPart 68) and is the reason that this risk management plan has been developed. The City of Waldron is committed to operating a safe facility both for it's employees and the public at large. The cylinders containing the liquid chlorine are stored in a small metal framed building located apart but nearby the main operations building. There is space for as many as six (6) ton containers in and outside of the building. There are usually only two (2) full ton containers in the building and connected to the system at any one time. It is common to have one reserve container for each container in service.It is the policy of the Waldron Water Department to have three (3) full or at least partially full ton containers on site. This represents as much as 6000 pounds of chlorine. The chlorine building is located near the entrance to the plant site but is separated from public roads by a lockable chain link fence with barbed wire at the top. When the chlorine containers arrive by truck at the site they are removed and placed inside the building.Empty containers are removed from the building and placed on the truck. The worst case release scenario envisions the accidental release of the entire 2000 pound contents of the container within a 10 minute period. This could occur as a catastrophic failure of the container due to corrosion,impact or construction defects. (Scenario I.D. CLW-2: AWWARF Model RMP Guidance). The container could be dropped while being lifted and transported into the building. If that occurred while it was outside the building there would be no passive mitigation measures; such as dikes,berms or other enclosure, available to contain the spilled liquid chlorine. The worst case scenario does have an off site impact. It is estimated that the distance to the toxic endpoint of the gas cloud emanating from this accidental liquid release could be a 3 mile radius from the plant site. (Table 5-1 page 5-6; AWWARF: Model RMP Guidance) The entire city of Waldron is within this radius. The alternative release scenario is deemed to be more probable than the worst case scenario but less onerous. This scenario envisions the release of approximately 300 pounds of chlorine as a gas. This could occur when the ton container is in active use. At this time it is operating in the gas feed mode which is the typical way that the system operates at Waldron. In this scenario the maximum average sustained release rate is 10.5 pounds per minute for 60 minutes. T his could occur due to a bad connection or a valve failure. Gas could be released through the 5/16 inch diameter valve body opening. (Scenario I.D. CLA-3 : AWWARF Model RMP Guidance). If this occurred the only passive mitigation measure currently available to contain the gas release would be the building itself and that presumes the doors to the building are closed. The only active mitigation measure that is in place is the gas pressure reducing valve with automatic switchover vacuum regulator. This valve functions to reduce the pressure of the gas flowing out of the container. The vacuum regulator serves to further reduce the gas pressure to a vacuum. Loss of vacuum for any reason such as a break in the downstream gas tubing causes the regulator to shut off the gas supply. It requires mechanical input (springs) in order to function. This alternative release scenario likewise has an off site impact. In this case the distance to the toxic endpoint of the gas cloud is estimated at 0.56 m iles radius from the plant site.(Table 5-5: page 5-22: AWWARF: Model RMP Guidance) The City of Waldron does not fall into this circle however there are inhabited residential and commercial buildings within it. As a first step in the general accident release prevention program the Waldron Water Department's policy shall be to inventory no more chlorine at the plant than is absolutely necessary to meet the goal of producing a potable and bacteriological safe drinking water for it's customers. The Water Department recognizes the need to strike a balance between this goal and the goal of minimizing risk to the public due to accidental chlorine gas release. However,the inventory must not be so reduced as to run out of the key component necessary to properly disinfect drinking water. The next step shall be to reinforce and strengthen existing Water Department policy to safely handle chlorine containers and all the system components necessary to transmit to its appli cation points within the treatment plant. The prevention program will be reviewed and edited to incorporate hazard analysis techniques. These shall be based upon the recognized industry standards and state and federal rules and regulations that apply to the use of chlorine in water treatment plant applications. These include but are not limited to the Chlorine Institute pamphlets, American Water Works Association publications,equipment manufacturer's printed instructions, and the Arkansas Department of Health's Rules and Regulations Pertaining to Public Water Supply. Operating procedures shall be continually reviewed to assure that adequate supplies of replacement parts and tools are available,that personal protection equipment is on hand and in a ready for use condition, and that gas detection,alarm, ventilation and container handling equipment is functioning properly. Personnel training is an ongoing program at the Waldron Water Department. Several of the op erators have already obtained their completed licenses and others are working towards that goal. The training program includes certification in the use of self contained breathing apparatus,confined space entry,and other safety measures. There has been one accidental release of chlorine in the past five years. The amount of the release is not known but was small; probably less than a few pounds. It occurred as a result of a improperly fitted lead washer at the container valve connection. The container valve was shut off and no injuries resulted from the leak. No evacuations were necessary from the plant site or nearby area. The emergency response program at Waldron consists of coordination of plant operators with the city fire department and county sheriff personnel by telephone and radio. Evacuation of the plant site and nearby public can be achieved through these coordination efforts.A public notification system does not now exist.However,city offi cials are discussing the implementation a electronic warning system with pole mounted horn annunciators located at various points throughout the affected area or perhaps the use of a warning message interrupt system on the local cable TV provider. Such systems are and can be used for tornado alerts as well. Certification programs in the proper methods of container changeout,use of self contained breathing apparatus and general waterworks operation have been in place and will continue to be updated and revised .First Aid and C.P.R. training shall be included. A program to include safety and emergency response drills will be instituted. An organizational chart depicting who does what,when, and how is being developed. People will be assigned to a position in this organizational chart so they will know their role. |