North County Water Reclamation Facility - Executive Summary |
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It is the policy of Collier County to operate safe wastewater treatment facilities, reducing to the greatest extent possible any hazards associated with our processes and reducing any subsequent risk to the surrounding community, employees and the environment. It is also our policy to work with the surrounding community and local emergency response agencies, and promote a spirit of cooperation and teamwork to provide an effective contingency plan in the unlikely event that a process incident occurs at one of our facilities. Regulated Substances The primary activity at the North County Water Reclamation Facility (NCWRF) is municipal wastewater treatment. Chlorine is the only 40 CFR 68 regulated substance at the facility. Chlorine is used primarily as a disinfectant. The maximum amount of chlorine at the facility is 12 tons. Worst-Case Release Scenario (WCS) The Worst-Case release scenario according to EPA's Offsite Consequence Analysis Guidance document is "the greatest amount held in a single vessel." The worst-case scenario is the complete release of chlorine from a one-ton container. The chlorine toxic endpoint defined by 40 CFR Part 68 is 0.0087 mg/l which is equivalent to 3 parts per million by volume (ppm). According to the American Industrial Hygiene Association (AIHA) Emergency Response Planning Guideline (ERPG)-2, this toxic endpoint is specified 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 irreversible or other serious health effects or symptoms which could impair an individual's ability to take protective action." The SLAB computer model was used to simulate the worst-case scenario. The maximum distance to toxic endpoint is 2.93 miles. A worst-case release is unlikely due to the materials of construction of the chlorine container. In addition, a comprehensive risk management program has been developed to prevent accidental releases. Alternative Release Scenario The alternative release scenario is most likely to occur than the worst-case scenario. For the NCWRF, it is assumed that the pipe manifold connecting the two 1-ton chlorine containers fails and chlorine is released for 2.5 hours. The maximum distance to the toxic endpoint for the alternative release scenario is 0.42 miles. Accidental Release Prevention Program Collier County is in compliance with 40 CFR 68. The County has conducted a comprehensive review of the chlorine system as well as administrative, technical, operating and maintenance procedures, in addition to the other required program elements of the regulations. The Risk Management Program addresses actions to minimize the likelihood of an accidental release and to minimize the impact if one occurs. Five-Year Accident History The NCWRF has not had a significant release of a hazardous substance as defined by 40 CFR 68. Emergency Response Program This facility has an emergency response program that is coordianted with the Collier County Comprehensive Emergency Response Plan (ERP) that has been prepared in accordance with all local, state and federal regulations. Planned Changes to Improve Safety The hazard review resulted in the development of a list of improvements and an implementation schedule. This is included in the Risk Management Plan (RMP). Continued training and practices documented in the RMP will continue to improve safety at the facility. Some of the more significant improvements are listed below: To Be Completed by August 1999 Due to the chemical nature of chlorine, any work performed in the chlorine area that involves heat or sparks should be closely monitored. Hot work permitting should be implemented. Prepare and implement a Preventive Maintenance (PM) program for the entire system. The PM program should include the following equipment: Metal parts in the chlorine line Manifold piping Valves, including the ball valve downstream of the vacuum regulator Filters Strainers Tubing at vacuum monitor Vent line Chlorine feed lines Install screen on the discharge end of the vent line from the pressure relief valve. This will discourage mud dauber wasps from building nests in the pipe and help prevent blockage. Modifications to the vent line from the pressure relief valve should be made to prevent potential disconnection. In case the gas filter gets clogged, spare filters should be purchased and kept on site. If the vacuum regulator fails in the open position, the pressure relief valve should be configured to release to a sensor to alert the operator. To deter untrained individuals from entering the chlorine area it should be designated as a "Restricted Area" with posted signs. To Be Completed by October 1999 Request Standard Operating Procedures and certific ation that chlorine meets AWWA specifications from the chlorine supplier. Request maintenance requirements of the contractor used to service the chlorine sensor and alarm system. Make modifications if necessary. Add yellow "Chlorine" labels to chlorine lines. To Be Completed by June 2000 Expand on the existing emergency plan for the plant personnel. The evacuation plan should include two separate egress routes. To Be Completed by January 2001 The facility currently plans to convert from chlorine use to sodium hypochlorite by January 2001. The following recommendations have been made in the event that the conversion is not implemented. Provide operator training on equipment components. The chlorine release alarms should be connected to the plant monitoring system. This will enhance emergency notification procedures. Install cable securing system for all ton containers. Securing containers will provide additional anchoring during a hurri cane or other severe weather events. |