Eugene/Springfield Metropolitan WPCF - Executive Summary |
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EUGENE/SPRINGFIELD METROPOLITAN WPCF RISK MANAGEMENT PROGRAM EXECUTIVE SUMMARY ' 68.155 ACCIDENT RELEASE PREVENTION The Eugene/Springfield Metropolitan Water Pollution Control Facility (WPCF) places a high priority on safety. The WPCF has an active Safety Committee consisting of union represented staff and managerial staff working together to provide a safe, healthy workplace. Our Safety Committee has been in place since plant startup in 1984. The overall safety record of the WPCF is very good. Operational staff responsible for handling the regulated chemicals is very experienced and well trained. All equipment at the facility is on a preventive maintenance schedule. WPCF management provides strong support for safety and readily provides all tools and personal protective equipment to ensure compliance with written safety procedures. FACILITY AND REGULATED SUBSTANCES HANDLED The WPCF operates a conventional activated sludge wastewater treatment facility. The facility went on line in 1984 and treats wastewater from a region that includes Eugene, Springfield, and the unincorporated areas of River Road and Santa Clara. The WPCF plant is sited on approximately 100 acres in northwest Eugene. The site is bounded on the east by the Willamette River. As a part of the wastewater treatment process the toxic chemicals chlorine and sulfur dioxide are used to disinfect and dechlorinate the plant effluent before discharge to the river. The facility was constructed with an enclosed chemical storage building equipped with a chemical scrubber system. In the unlikely event of a chemical leak, the scrubber system will neutralize either chlorine or sulfur dioxide before it can escape to the atmosphere. The maximum inventory for chlorine is listed as 20 one-ton cylinders (40,000 pounds) and eight one-ton cylinders (16,000 pounds) of sulfur dioxide. Actual inventory at any given time is much less. Typically the facility will have about twelve (12) tons of chlorine and four (4) tons of sulfur dioxide on site. Our standard operating procedure is to have only one cylinder of chlorine and sulfur dioxide in use at one time. All other cylinders are either not connected or left isolated by a series of valves including the main tank valve. Equipment used to feed the chemicals are designed specifically for the task and are constructed of compatible materials. The facility uses about 100 tons of chlorine and about 35 tons of sulfur dioxide per year. Shipments of the chemicals are received via trucks and flatbed trailers. The current supplier is All-Pure out of Tacoma, Washington. On the average, deliveries to the facility occur about once per month. WORST-CASE RELEASE SCENARIO Risk management planning requires the development of a worst-case release scenario. The release is defined as a leak of the entire contents of the largest single vessel on site. In Eugene's wastewater treatment plant, this means the contents of one, one ton cylinder. The release is to be evaluated based on a ten minute period that equates to a release of 200 pounds per minute. The scenario was modeled using RMP*Comp version 1.06, which is available via the Internet from EPA's CEPPO Web site. Only passive mitigation is allowed in this scenario, so the containment building was factored in at 55 percent according to guidance documents. The model calculates the concentration of the chemical in a dispersion pattern of 360 degrees until an endpoint of three ppm (parts per million) is reached. Output from the model showed an endpoint radius of 0.9 miles from the source. In the Eugene facility, the containment building would exceed the passive mitigation factor of 55 percent because it is totally enclosed with tight fitting doors and normally closed inlet louvers. Air dispersion models such as RMP*Comp are intentionally conservative in nature. This means the endpoint concentration of three ppm would not likely reach a distance of 0.9 mile as sugge sted by the model. ALTERNATIVE RELEASE SCENARIO The plan also requires the determination of an alternative release scenario that allows the use of active mitigation such as the scrubber system. Again the RMP*Comp model furnished by EPA was used for this evaluation. The scrubber system was assumed to be 99 percent efficient and the endpoint concentration was reached at a distance of less than 0.1 miles. The radius does cross the fence line of the facility on the east side, but no dwellings exist in this area. The only off-site consequences under this scenario are a bike path, and a recreational vehicle dump site on the north side. Both chlorine and sulfur dioxide were analyzed under the alternative release scenario and similar endpoints were determined. The scenario itself was based on a break in a one-inch pipeline used to transport liquid chlorine or sulfur dioxide from the cylinder to the evaporator. A pipeline break was chosen for the analysis not because it represents the most likely scenario, but it does represent a more conservative estimate. The release rate from the broken pipeline in pounds per minute was determined using tables furnished in the guidance documents from EPA for wastewater treatment facilities. GENERAL ACCIDENTAL RELEASE PREVENTION The Wastewater treatment facility has been in compliance with the OR-OSHA Process Safety Management (PSM) rule since the enactment of the rule in 1992. The development of the PSM documents included most of the Process Hazard Analysis (PHA) efforts required under the new RMP rules. The facility is equipped with redundant safety systems including leak detectors and continuous monitoring by a Distributed Control System (DCS). The DCS is monitored by operations staff and all alarms are displayed on hard copy printouts. A video surveillance camera is positioned inside the containment structure so the console operator can monitor tank change procedures and visually verify conditions inside the area. An i ntrusion alarm system is activated during the night-time hours. The leak detectors and scrubber system are included in the preventive maintenance program that includes frequent calibrations and testing. The structure has been evaluated by the Fire Marshall and a determination was made that fire hazards are minimal and no sprinkler system retrofit was needed. The structure was also recently given a seismic evaluation and retrofit modifications have been made to the roof of the scrubber room. FIVE YEAR ACCIDENT HISTORY No accidental releases have occurred during the past five years. EMERGENCY RESPONSE PROGRAM The emergency response program at the facility has been in place for many years. The program uses the Eugene Fire Department's HAZMAT response team. A comprehensive procedure is in place to notify the HAZMAT team via the 9-1-1 dispatch center. The facility is equipped with an audible alarm system to notify plant staff in the unlikely event of a release. The alarm system i ncludes flashing lights on the exterior of the containment structure, facility-wide audible alarms using modulated tones for different alarm functions, and a Public Address (PA) system. Traffic control gates can be used to prevent access to the area. This includes the recreational vehicle dump site which is can also be accessed by the PA system. The system is tested on a preventive maintenance schedule. Training drills are conducted by the Fire Department on a scheduled basis. The 9-1-1 dispatch center is installing a Community Emergency Notification System (CENS) for the purpose of providing public notification. The wastewater facility will be enrolled in the CENS program to notify area residences should the necessity ever arise. The HAZMAT team uses the Incident Command protocol, and the decision to implement public notification would be made by the Incident Commander on the scene. PLANNED CHANGES TO IMPROVE SAFETY The facility has not determined a need to install any addi tional safety systems at this time. YEAR 2000 PREPAREDNESS The facility has undergone extensive Y2K preparation and will be prepared for any potential problems which may arise due to computer or control failures. |