City of Naples Water Treatment Plant - Executive Summary |
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It is the policy of City of Naples to operate safe water 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 the facility. Regulated Substances The primary activity at the Water Treatment Plant (WTP) is municipal water 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 20 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-cas e scenario is the complete release of chlorine from a one-ton container. The worst-case scenario may not consider the use of active mitigation such as emergency scrubbers. The chlorine toxic endpoint defined by 40 CFR Part 68 is 0.0087 mg/l which is equivalent to 3 parts 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 2.08 miles. This distance considered the mitigation provided by the building but did not include the use of active mitigation measures such as the emergency scrubber. 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 modeled is the worst-case scenario with the emergency scrubber in operation It is assumed that a one-ton container reputes and releases all of its contents within the Process/Chemical building. When the release is detected, the emergency scrubber is activated. There is no off-site impact for the alternative release scenario. This alternative release scenario is not likely to occur; however, it demonstates that off-site impacts do not occur even for the worst-case scenario when the active mitigation system is used. Accidental Release Prevention Program City of Naples is in compliance with 40CFR68. The City has conducted a comprehensive review of the chlorine system as well as administrative, technic al, operating and maintenance procedures, in addition to the other required program elements of the regulations. The City has both passive mitigation, an enclosed building, and active mitigation, an emergency scrubber, to minimize the consequences of an accidental release. 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 WTP 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 coordinated 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 a nd 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 the vendor's Standard Operating Procedures, training requirements and staff resumes for all on-site workers, as well as certification that chlorine meets AWWA specifications. Procurement documents should specify that the driver must proficiently speak and understand English. Procurement documents should specify the delivery vehicle requirements, and remind vendors that scheduling with the operator is a safety concern. Containers should meet all applicable codes and hydrostatic testing requirements. To Be Completed by August 1999 Notify vendor, in writing, about acceptable delivery vehicles. Purchase spare fuses, and replace any faulty wrenches. Keep spare parts in stock. Also purchase 3-position tags that denote whether a container is empty, full, or in-service. Weak or old ammonia may no longer function properly. Staff should purchase 26 Baume ammonia solution. 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, with hot work in the chlorine area supervised by qualified plant personnel. When the regulator yoke is over-tightened, damage can occur. Include proper yoke tightening methodology in staff training, and modify the current wrench to eliminate clearance/connection problems. Remove improper wrenches from the work area. Move header and valves to a safer location. The header and valves are currently a trip hazard. Begin testing alarms circuit and electrolyte once per week. Add at least two fire extinguishers. Due to the flammability of lime dust, consider installing smoke detectors in the chlorine facility, and replace them frequently. Begin annual reviews of emergency response plan, and increase coordination with emergency response personnel. Provide quarterly inspection and testing of caustic solution by the City's laboratory to ensure that the caustic is the appropriate strength to be effective. Include inspections of the integrity of the wall as part of an overall scrubber system review. 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 November 1999 Provide added protection to the chlorine building to help prevent structural damage in case of a vehicle accident. Purchase wrenches so that each ton container has a wrench. Keep spare wrenches in stock. Existing vacuum regulators do not provide equal draw from containers. Vacuum regulators should be replaced. A preventive maintenance (PM) and replacement program for the chlorine system should be prepared and implemented. The PM program should include the following equipment: Ma nual ball valve on header Vacuum regulator Injector check valves Valves on the solution line Chlorinator Pressure gauges Tubing and piping, including flexible tubing Rate controller valve Connect UPS on the chlorine system leak detectors to eliminate power loss to the alarms, and to eliminate false leak alarms. Relocate the safety shower to a better location, and test the safety showers and eye wash stations each month. To Be Completed by January 2000 Extend the driveway to allow vehicle access to empty containers. Replace the crane/hoist, which has exceeded its effective service life. As part of procurement of a new hoist, plan to have a breaker disconnect instead of a fusible disconnect. Consider that the new hoist include a manual let-down. Eliminate automatic valves for switch over and operate manual valve switch over, or revise system to have a pressure operated switch over system with a single regulator. Replace wooden decking in chlorine area. This is a fire hazard. Create a check-in policy for all visitors to the plant site. Provide appropriate color coding for chlorine pipes, also denoting flow direction. Enforce the OSHA standards to prohibit use of respirators by employees with beards. Because the caustic is often diluted by rain, approach the system's designer, RMJ, about possible modifications to the rain cap and exhaust stack. Purchase an additional air bottle for use with SCBAs. Provide annual cleaning and maintenance of the emergency dampers. Incorporate caustic solution leaks or discharges into the emergency spill response plan. Provide annual on-site hazardous materials training. Consider air-operated shutdown valves on the containers. These could be tied to an alarm system. Consider changing to an alternate disinfection process that does not rely on hazardous chemicals that exceed OSHA/EPA Threshold quantities. To Be Completed by August 2000 Consider installing a panic alarm at the chlorine facility. Consider tying an auto-dialer into the alarm system to notify the fire department immediately. Master lock the facility to restrict access to all areas. Consider planting thorny landscaping (natural deterrents) by the fence to prevent anyone from climbing the fence to obtain access to the facility. ost "Restricted Area" signs by the chlorine area, and review all signage at the facility. Verify that appropriate international chemical signage is in place, per NFPA. Consider providing an automatic security gate with a call box and television monitor to help prevent unauthorized personnel from entering the facility grounds. Consider adding the chlorine scrubber operating status to the SCADA system. Provide nylon strapping to help secure all ton containers in case of a hurricane or other severe weather event. Check that a second egress route, remote from the first one is included in the plant's emergency evacuation plan for plant personnel. Verify that a reassembly location has been identified f or staff. To Be Completed by January 2001 Provide an additional entrance to the plant from the parks and parkways access road, with an additional security gate at the east side of the plant. This will allow for improved ability to maneuver large vehicles. In case the vacuum regulator fails while it is open, a sensor with an alarm system should be installed on the vacuum release line. Correct chlorine application point to eliminate the release of gas to the atmosphere. This currently causes some false alarms. Consider providing secured storage of empty containers for added safety in case of a hurricane or other severe weather event. Consider training operators for a Level 3 Response in case of an emergency, and purchase necessary equipment. |