North Columbus WRF - Executive Summary |
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Executive Summary Policy Statement It is the CWWs policy to operate safe water and wastewater treatment plants, reducing to the greatest extent possible any hazards associated with the processes and reducing any subsequent risk to the surrounding community, personnel, and environment. The policy includes working with the surrounding community and local emergency response agencies, to promote a spirit of cooperation and teamwork, to orchestrate an effective contingency plan in the unlikely event of a process incident occurring at the North Columbus WRF. Stationary Sources and Regulated Substance Handled Primary Activities Water treatment. Use of Regulated Substance ? Chlorine is used primarily as a disinfectant. Other possible uses of chlorine are odor control and iron removal. Quantities Handled or Stored ? Chlorine at Water Treatment Plant: Total Amount Stored: 12 one-ton containers, equivalent to 27,600 pounds. ? Chlorine at Pump Station: Total Amount Stored: 4 one-ton conta iners, equivalent to 9,200 pounds. Worst-case Release Scenario Chlorine WRS: Failure of one liquid chlorine container at the Pump Station, resulting in a release of 2,300 pounds of chlorine in 10 minutes. The container is stored in a building with wood roofing. Passive mitigation is not considered because the roof may not withstand an explosion. Therefore, the release rate of 1.74 kg/s is modeled using DEGADIS 2.1. Distance to Endpoint: Under the worst-case weather conditions prescribed by the RMP Rule, the distance to a toxic endpoint of 3 ppm is 2.53 miles or 4.07 km, beyond which there will be enough dispersion that the hazard to the public will no longer exist. Alternative Release Scenario Chlorine ARS: Release of chlorine from a <-inch-diameter pipe connecting the chlorine container to the feed manifold. For a release duration of 20 minutes, the release rate within the building is 0.042 kg/s. The actual release rate is 55 percent of the total chlorine released in the encl osed building because of passive mitigation . Therefore, the release rate from the building, 0.023 kg/s, is modeled using DEGADIS 2.1. Distance to Endpoint: Under realistic weather conditions of 3.0 m/s wind speed and a wind stability class of D, chlorine would travel 0.28 miles or 0.45 km before dispersing enough that it no longer posed a hazard to the public. Accidental Release Prevention Program and Chemical-specific Prevention Steps The North Columbus WRF is in compliance with the RMP Rule, 40 CFR 68. The facility has conducted a comprehensive review of all systems, as well as administrative, technical, and operating and maintenance procedures, in addition to the other required program elements of the RMP Rule. A hazard review was conducted at this facility using a What-If analysis. Five-year Accident History The North Columbus WRF has never had a release of chlorine resulting in offsite dispersion or property damage, or in injuries onsite. Emergency Response Program The CW W has an Emergency Response Program that applies to the North Columbus WRF, which coordinates response efforts with the local fire departments Hazardous Materials (HAZMAT) team, the police department, and the hospital. Response activities also have been discussed with the Georgia Emergency Management Office. Planned Changes to Improve Safety It was observed during the hazard review that the North Columbus WRF has the necessary equipment and the operating and training procedures required for the safe operation of the chlorination system. However, the following recommendations for improving the safety of the chlorination process were made: 1. Quarterly inspections of chlorine leak detectors 2. Installation of a wind sock to indicate wind direction during an accidental release |