CITY OF ST. AUGUSTINE WWTP NO. 1 - Executive Summary |
1. EXECUTIVE SUMMARY 68.155 The City of St. Augustine Utilities Department operates the City of St. Augustine Wastewater Treatment Plant #1 at 501 Riberia Street, St. Augustine, Florida, St. Johns County, Florida. This plant is one of two plants operated by the City. Both the water plant and wastewater plant have quantities of regulated hazardous chemicals above the EPA threshold. The City has a unified Risk Management Program which applies to each plant. Only Wastewater Treatment Plant #1 operations and policies are presented in this Plan. 1.1. ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES (a) The City of St. Augustine Wastewater Treatment Plant #1 accidental release prevention policy involves a unified approach that integrates technologies, procedures and management practices. The plant prevention program complies with all applicable procedures of the U.S. Environmental Protection Agency (EPA) Risk Management Program (RMP) 40 CFR-68, Prevention Program. 1.1 .1. MANAGEMENT SYSTEM (a)(1) The City of St. Augustine has a management system in place which is lead by the City Manager, who oversees the implementation and on-going use of the RMP elements. This program, along with other City-wide and plant-specific policies, eliminates and /or reduces the likelihood of a hazardous chemical release at the plant. 1.1.2. PREVENTION PROGRAM LEVEL 3 (a)(2) The City of St. Augustine maintains policies, procedures and systems as part of their prevention program. These are applied to each treatment plant and specifically the Wastewater Treatment Plant #1. The program addresses each of the EPA Program Level 3-listed 12 elements, plus RMP elements needed to implement the program, and the like elements in place in the plants? OSHA PSM program. These are maintained in The City of St. Augustine?s Document Management System (DMS). 1.2. THE CITY OF ST. AUGUSTINE STATIONARY SOURCE AND REGULATED SUBSTANCE HANDLED AT THE ST. AUGUSTINE, FLORIDA SITE (b) Th e City of St. Augustine Wastewater Treatment Plant #1 employs 9 full-time employees engaged in Wastewater Treatment Plant #1 and field operations. Chlorine is used as part of the treatment process. 1.2.1. SITE DESCRIPTION (b)(1) The site is owned and operated by The City of St. Augustine Utilities Department. The site is located at 501 Riberia Street,, St. Augustine, St. Johns County, Florida. The site is located in a block area, boarded by (ICW) Intercoastal Waterway on the east, San Sabastian River on the west, Cerro Street on the north and San Sebastian River on the south. The Plant includes a separate chlorine storage building and adjacent control distribution system that is contained in a special process room of the wastewater plant building. The boundaries of the chlorine system subject to the RMP regulation include the Bulk Chlorine Storage and Feed Control rooms and the associated vent makeup and exhaust systems. These are detailed in the Process and Instrument Drawing s (P&ID) which are part of the plant Process Safety Information (PSI). 1.2.2. REGULATED SUBSTANCE (b)(2) Chlorine is the only regulated substance on site which exceeds the EPA 40 CFR-68 rule threshold quantity. The City of St. Augustine chlorine process was installed as part of the process of purifying water for public consumption. It operates under permit from the State of Florida Department of Environmental Protection (FL DEP). The chlorine is received, stored and distributed to five process control systems. Chlorine is an EPA and OSHA-listed toxic chemical. It is an irritant and it is corrosive. Chlorine is a halogen with the formula Cl2. It is a chlorinating or oxidizing agent that is not flammable. It has a 1 ppm OSHA ceiling Permissible Exposure Limit (PEL) and a NFPA health rating of 4, severe; with immediate and delayed health hazards. Chlorine is not a carcinogen. 1.3. WORST AND ALTERNATIVE CASE RELEASE SCENARIOS (c) Two offsite consequence analyses were conducted which include two chlorine release scenarios. The first is a "worst case release". The second is a more probable "alternative release scenario". The first scenario is defined by EPA, which states that "the ...shall assume that the... maximum quantity in the largest vessel ...is released as a gas over 10 minutes" due to an unspecified failure. The alternative scenario is defined as "more likely to occur than the worst-case scenario". Atmospheric dispersion modeling was performed to determine the distance traveled by the chlorine released before its concentration decreases to the "toxic endpoint." The EPA selected endpoint for chlorine is 0.0087 mg/l which equals 3 ppm. The 3 ppm endpoint is the Emergency Response Planning Guideline Level 2 (ERPG-2). This is defined by the American Industrial Hygiene Association (AIHA) 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 developi ng irreversible or other serious health effects or symptoms which could impair an individual?s ability to take protective action." The residential population within a circle with a radius corresponding to the toxic endpoint distance was defined, "to estimate the population potentially affected." 1.3.1. WORST CASE (c)(1) Atmospheric dispersion modeling for the worst case scenario was performed using the EPA assumptions. Results demonstrate a distance of 1.3 miles to the toxic endpoint. The residential population that could potentially be affected by the release is estimated at 11,336 people. There are schools, residences, hospital, recreation and industrial plus historic areas included in that release area. 1.3.2. ALTERNATIVE CASE (c)(2) The alternative release scenario involves the failure of the yoke assembly regulator of the pressure system connected to one of the one-ton containers. This failure is equal to creating a 1/16 inch diameter hole in either the yoke assembly, th e drip tube, a pipe, or even the container. Modeling using the EPA water guidance demonstrated the rate of chlorine release is 30.0 lb./min. The toxic endpoint distances determined is 0.10 miles. The residential population that would be impacted by this release is estimated at zero. 1.4. ACCIDENTAL RELEASE PREVENTION PROGRAM (d) The City of St. Augustine accidental release prevention program is based on OSHA?s PSM program and EPA?s RMP Level 3 prevention program. The PSM program has been in place and effectively used for several years. It is part of the plants operating culture. There are two parts to the program. The first is the general overall City-wide and Wastewater Treatment Plant #1 site program. The second is the chlorine-specific actions within the site program. This is coordinated with the City of St. Augustine Fire Department. 1.4.1. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM (d)(1) Plant-wide, many elements of the prevention program are used for all operati ons. An overview of the generally written programs are listed below: ? The City of St. Augustine has detailed process safety information on each of its operations. ? The DMS, document maintenance system, is integral to the management of change for all operations on site control. ? Training is the backbone of employee knowledge, job operations and is ongoing in each area. Employee training in operations and maintenance emphasizes awareness of the hazardous and toxic properties of all chemicals used. ? Maintenance and preventive maintenance are used for all operations making mechanical integrity a part of each piece of equipment. ? Incident investigations of accidents and near-miss incidents ensure we learn from each event as well as correct the causes of the incident. ? Employees participate in all aspects of the plant as listed below under emergency response. ? Safe work practices are used throughout the facility including: 1) Hot Work Permits, 2) Lock Out Tag Out Permits, 3) Vessel Entry Permits, 4) Site Security, and 5) Breaking Into Chemical Lines. ? Contractors must meet The City of St. Augustine?s high safety and technical standards as part of selection and ongoing evaluations. Plus, City of St. Augustine demands training of contractors to our standards. 1.4.2. CHLORINE-SPECIFIC RESPONSE PROGRAM (d)(2) 1.4.2.1. Chlorine-Specific Policies and Procedures Chemical-specific prevention features of the plant include: the policies and procedures listed above and those of the chlorine specific program. These include: ? Specific procedures for the operation of the chlorine process. ? Completion of a Pre-startup Safety Review prior to startup of the modified chlorine system. The latest one was conducted on 4/21/1999. ? Specific emergency response procedures for chlorine releases as outlined below under both operating procedures and in the emergency response procedures. ? Specific training in the properties, hazards, handling requirements, and leak repa ir for chlorine. ? Finally, the details of both facility and equipment design are key to the safe operations of the chlorine system. 1.4.2.2. Facility Design The plant and support equipment of the chlorine storage building and control room meet and exceed design codes standards and good engineering practices. The building is equipped with ambient ventilation area. The control room has a fan ventilation system, which is on 24 hours a day. All the vent air and any fumes are diluted and then removed from the room by the vent system. 1.4.2.3. Equipment Design There are two types of chlorine pipe systems, high and low (vacuum) pressure. The high pressure chlorine piping system is made of chlorine compatible steel pipes or equipment. These materials are steel or chlorine compatible non-metallic compound (not corroded by chlorine) rated to 500 psig. The maximum pressure of the chlorine in the high pressure system is only 150 psig giving a 3 to 1 safety factor. This system is only inche s long leading from the chlorine container to the pressure regulator bolted to the container. The low pressure system operates under a vacuum pressure of 13 inches of mercury. All the pipe, tubes, and equipment are also chlorine compatible. The system is designed to 150 psig or complete vacuum giving it a large safety factor over the typical vacuum or positive pressure in it. There is a chlorine monitor which detects the presence of chlorine in the storage and control building room. The alarms and lights in the plant alert employees of a potential chlorine leak. 1.5. FIVE-YEAR ACCIDENT HISTORY (e) The City of St. Augustine Riberia Street plant had no accidental releases of chlorine in the past five years per EPA 40 CFR 67.42 (a). 1.6. EMERGENCY RESPONSE PROGRAM (f) Emergency response procedures are contained in the City of St. Augustine Contingency Plan (Emergency Response Plan). The plan includes an emergency response "decision tree" and a notification plan. The Plant also has site specific emergency actions defined in the plants operating procedures. Emergency response drills and drill evacuations are conducted annually by the operating department. Emergency operation and response procedures are also reviewed at that time. The emergency response program (contingency plan) is coordinated (reviewed by) with the St. Augustine Fire Department, which coordinates with Local St. Johns County Emergency Response Planning Committee (LEPC) and Fire Department HazMat Team. All are located in St. Johns County, Florida. Copies of the program are given to key local agencies including: fire, medical, rescue, management, and police departments in St. Augustine. Besides the specific emergency response program, key elements of the prevention programs are incorporated in the operating culture of the City of St. Augustine wastewater plant. The Contingency Plan procedures detail the actions and responses to chlorine spills (releases). The plan includes training of all chlorine-area operators, The primary response team include the St. Augustine Fire and Rescue, plus the local Haz Mat Teams. All of these respond to severe chlorine leak situations. Actions include catastrophic, severe, and moderate leaks. A Chlorine "B" Leak Repair Kit is maintained at the Wastewater Treatment Plant #1 to aid in stopping leaks. Public notification is facilitated through the St. Augustine Police and City of St. Augustine Sheriff?s Office, which has an automated emergency dialing message system for public notification. 1.6.1. PERSONNEL (f)(1) Personnel are the key resource of the City of St. Augustine?s prevention program. City employees make up the operators and emergency first response teams. The City of St. Augustine fosters a high level of involvement in every aspect of the chlorine system operations including participation in : ? PSM/RMP safety teams, ? Development of the operation procedures, ? Hazard evaluations, and ? On-going training of the operators and other involved staff. 1.7. CHANGES TO IMPROVE SAFETY (g) Changes to improve safety (recommended actions) were identified in the February 26, 1999, internal safety HazOp, tour, and audit of the PSM program to meet requirements of the Risk Management Prevention Program. These recommended actions have now been evaluated and implemented as required. An Audit was conducted to review the PSM program. The key safety action items were completed. See the "Update" Section 6 of this report. The City of St. Augustine continually reviews implemented operating procedures for potential safety improvements for all of its operations. Currently, the City of St. Augustine management team and process safety team are reviewing potential upgrades to the existing design of the chlorine operations to make the system even safer to prevent a release and minimize consequences in the event of a release of chlorine. |