CWL - West Side Wastewater Treatment Plant - Executive Summary
Owner Information: |
City Water and Light (CWL) is a publicly-owned utility that provides water, wastewater, and electrical services to the city of Jonesboro, Arkansas (population approximately 52,000).
The CWL - West Side Wastewater Treatment Plant is a drinking water treatment plant with a capacity of approximately 8 MGD. Chlorine is used as a disinfectant in the treatment process, and the maximum amount stored at this facility is approximately 4,000 pounds.
Release Prevention and Emergency Response:
CWL's management takes safety issues and regulations very seriously. It is our goal to ensure that all our operations are safe to our employees, the community, and the environment. The position of Compliance Specialist was created in recent years to help us reach that goal. We have an extensive in-house safety program that includes a manual entitled Chlorine Handling Procedures and Accidental Release Guidelines, which details our chlorine handling and leak res
ponse program. In addition, we have a Disaster Plan that also deals with chlorine releases during a disaster. While we at CWL feel our present chlorine program is an exceptional one, we want to continue to strive to improve it.
Two leak scenarios were considered for this facility. The worst-case scenario was modeled as a 1-ton chlorine tank leaking its total contents over a 10-minute period as required by the regulations. The alternative release was a 320-pound release from the 5/16"-diameter valve body opening of a 1-ton container occurring over a 30-minute period. Information for the two leak scenarios was obtained from the Compliance Guidance and Model Risk Management Program for Water Treatment Plants by the American Water Works Association Research Foundation and American Water Works Association (1998). According to this source and considering that the plant is in an urban setting, the worst-case release would have a source-to-end-point distance of 2.6 miles, wh
ile the alternative release distance would be 0.48 miles. It is estimated that the worst-case release would impact approximately 12,000 people living in a 2.6 mile radius of the plant, and the alternative release would impact approximately 550 people living within 0.48 miles of the plant.
Release Prevention Program:
More and more regulations are being placed on chlorine-handling facilities such as the West Side Wastewater Treatment Plant. Certainly CWL plans to follow all applicable regulations pertaining to chlorine use and handling. In addition to just following the regulations, we want to explore all feasible options to minimize the risks to our employees and the public at large. We have a very good chlorine handling record; however, CWL management is committed to improving all areas of chlorine use and handling. Management is proposing additional training time and materials, as well as considering new mitigation systems. Our release prevention program starts with our chlorine pr
ovider. Our present provider maintains their tanks and valves much better than our previous provider. We have also requested a copy of their testing and maintenance guidelines for their cylinders to ensure that they continue to provide us with structurally sound containers and well-maintained valves. The next step in our program involves proper handling by CWL personnel. We presently have at least two people present when handling chlorine containers. Although most of our employees have many years of experience and we have the CWL Chlorine Handling Procedures and Disaster Plan, we plan to continue to improve our training and handling techniques. Another phase of our plan is the process equipment. CWL uses vacuum-feed chlorinators at this facility, which means if a hole develops in process piping the system will pull in air instead of releasing chlorine. Thus, the equipment capable of leaking chlorine is essentially reduced to the bottle-mount chlorinators and the chlorine tanks. If a le
ak occurs in a tank, we have chlorine leak repair kits and numerous SCBA's, which allow our personnel to stop or minimize the leak. Finally, we also have chlorine leak detectors (Capital Controls Company, Series 1610B/1620B Gas Detectors), which provide both local and remote alarm signals. The remote alarm is transmitted from the plant to the CWL Dispatch Center, which is staffed continuously, via our SCADA (Supervisory, Control, And Data Acquisition) system. The alarms are also tested routinely to ensure their reliability.
Five-year Accident History:
CWL has had no accidental releases of chlorine from this facility in the past five years.
Emergency Response Program:
CWL has a good working relationship with the Craighead County LEPC, and we have provided written copies of the CWL Disaster Plan, which includes information on chlorine release response and notification. The LEPC officials and CWL have agreed that CWL personnel shall take the lead in responding to a chlorine leak at
our facilities because our personnel are more experienced and have received more specific training related to chlorine leak repairs. Our personnel have received chlorine training from outside sources such as the local water district. We have had in-house training classes that covered chlorine leaks, and we have discussed leak response in routine in-house operational meetings. In addition, our personnel have utilized training equipment such as "dummy" tanks and the standard chlorine leak repair kits to simulate leak repair procedures. If a release of 10 pounds or more occurs, our personnel are to notify the LEPC, the Arkansas Department of Environmental Quality, the National Response Center, the Environmental Protection Agency's Region 6 office (present contact Steve Mason), and the Office of Emergency Services (if unable to reach LEPC). Phone numbers for all these agencies are listed in the CWL Disaster Plan in the chlorine release section. Public notification would be coordinated wit
h the Jonesboro Fire Department, Jonesboro Police Department, and the LEPC, and, in the case of a major leak, would involve local radio and television stations.
Planned Changes for Safety Improvement:
At this time, a more structured written training schedule is being planned. In the future, additional annual training is almost a certainty. Also, more training materials such as videos, booklets, etc., are being reviewed for purchase. Periodically, probably annually, the RMP will be reviewed with employees involved in chlorine handling. The most significant change being considered in our chlorine operations at the present time is the addition of a chlorine scrubber for this facility. CWL has requested pricing and a list of technical specifications from a dry-type chlorine scrubber vendor and will continue to gather scrubber information. We hope to make a decision on this issue by mid-year of 1999 so the cost of adding scrubbers can be added to the 2000 budget, which will be developed
in late 1999.
CWL is committed to providing utility service to the city of Jonesboro in the safest manner that is feasible. The RMP has required CWL to reassess its total chlorine program. We feel that we have an exemplary safety record in handling chlorine, which is due in part to our existing chlorine program. However, we want to continue to improve our program by upgrading our training and perhaps by adding mitigation equipment. We realize the hazards of chlorine, and, in addition to the regulatory requirements, we want to continue to take steps to minimize the potential for a release.