Ft Myers South Advanced Wastewater Treatment Fac. - Executive Summary |
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It is the policy of the City of Fort Myers 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 South Advanced Wastewater Treatment Facility (SAWWTF) is municipal wastewater treatment. Chlorine and sulfur dioxide are the only 40 CFR 68 regulated substances at the facility. Chlorine is used primarily as a disinfectant. Sulfur dioxide is used for dechlorination. The maximum amount of chlorine at the facility is 20 tons. The maximum amount of sulfur dioxide at the facility is 10 tons. Worst-Case R elease 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 and sulfur dioxide toxic endpoints 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 for chlorine and 3.55 miles for sulfur dioxide. A worst-case release is unlikely due to the materials of construction of the chlorine and sulfur dioxide containers. 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 SAWWTF, it is assumed that the pipe manifold connecting the two 1-ton chlorine or sulfur dioxide containers fails and the chemical is released for 2.5 hours. The maximum distance to the toxic endpoint for the alternative release scenario is 0.42 miles for chlorine and 0.39 miles for sulfur dioxide. Accidental Release Prevention Program The City of Fort Myers is in compliance with 40 CFR 68. The City has conducted a comprehensive review of the chlorine and sulfur dioxide systems as well as administrative, technical, operating and maintenance procedures, in addition to the other required program elements of the regulatio ns. 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 SAWWTF 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 Lee 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 Prior To The Next Bid For A Chemical Supplier Request vendor's Standard Operating Procedures and certificati on that chlorine and sulfur dioxide meet AWWA specifications. Procurement documents should specify the delivery truck requirements. A truck hoist should not be used to unload containers. All containers should be marked in the upright position to maintain alignment during movement. Containers should meet all applicable codes and hydrostatic testing requirements. To Be Completed by August 1999 Due to the chemical nature of chlorine, any work performed in the chlorine areas that involves heat or sparks should be closely monitored. Hot work permitting should be implemented. Place expiration date on ammonia bottles used in testing for possible leaks. To Be Completed by November 1999 Chlorine containers must be rotated in the trunnions to properly align the valves prior to connection. Procurement of a specialized wrench for this use is recommended. To Be Completed by January 2000 Safeguards should be provided to prevent delivery trucks from colliding with the building. The ov erhead door should be removed to allow trucks to drive through the delivery area. Provide for repair or replacement of scales as needed. An annual preventive maintenance (PM) and replacement program for the chemical system should be prepared and implemented. The PM program should include the following equipment: Metal manifold piping Injector plugs Injector check valves Vacuum regulators Vent line from pressure relief valve In case the vacuum regulator fails while it is open, a sensor with an alarm system should be installed on the vacuum release line. The header pressure gauge should be moved to a better location. The valve should be tagged to identify its function and operating positions. The solenoid valve on the chlorinator discharge piping is not necessary for system operation. It should be removed. Restrictions are necessary regarding untrained personnel entering the chemical storage area. Signage should be reviewed and signs should be posted indicating "Authorized Personnel Only" or "Restricted Area". Signage on pipes to indicate their contents should also be reviewed at this time. Review labeling on piping and correct any deficiencies. To Be Implemented by June 2000 Implement annual load testing of the monorail mounted hoist. Provide regular training for the operators on the proper use of the monorail hoist system. Expand the existing emergency evacuation plan for plant personnel. The evacuation plan should include two separate egress routes and a designated location for staff members to reassemble. Additionally, emergency procedures should be developed in case of a valve leak that cannot be stopped by using routine measures. In case of power failure, a backup power supply should be provided to all sensors and alarms. Alarm investigation procedures should be developed and implemented. To Be Completed by January 2001 To eliminate the necessity for rolling containers during off-loading , the roller type trunnions should be repaired or replaced. A quality condition F bar should be available to rotate the containers in the trunnions for valve alignment. Installation of a bridge crane should be considered to allow off-loading of the containers from any starting position. A redundant chemical detection system for chlorine and sulfur dioxide should be installed in the storage area and the chlorinator area. The system should be checked quarterly to determine that it is functional. The chlorine and sulfur dioxide detectors should be placed on an uninterruptable power supply (UPS) to eliminate false alarms during power failures. Review alternative disinfection process regulatory, safety and costs considerations. Compare these processes to alternate for enclosing the chemical handling areas and providing a emergency scrubber to provide additional protection for staff and public. Provide emergency chlorine scrubbers or replace chemical process that use chlorine and su lfur dioxide. Modifications to the chlorine building should be considered to allow for unloading of chemical containers from all vehicles. |