Rattlesnake Reservoir Chlorination Facility - Executive Summary |
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RISK MANAGEMENT PLAN - INITIAL DISINFECTION FACILITY, DYER ROAD WELLFIELDS EXECUTIVE SUMMARY Irvine Ranch Water District (IRWD) has established a risk management plan according to EPA's regulations (40 CFR Part 68) to enhance already existing safety and emergency response programs. IRWD is extremely cautious in the handling of all chemicals and is very diligent about safety for its employees and its communities. IRWD staff is highly trained and utilizes modern equipment to monitor its facilities to provide safeguards, while effectively employing these useful chemicals. These chemicals play an important role in water treatment and water reclamation, enabling everyone to lead healthier lives. Accidental Release Prevention and Emergency Response Policies IRWD has an emergency response plan in effect to handle potential emergency situations at this facility. This plan was designed to meet the following objectives: 1.) To save lives. 2.) To minimize and avoid injuries. 3.) To protect the environment. 4.) To minimize property damage. Key elements of the Emergency Response Plan include: - A detailed Emergency Response Action Guide - Key phone numbers and contact points for the IRWD Emergency Response Team - Incident Command System (ICS) w/Unified Command interface - ICS position descriptions w/responsibilities - Vicinity and evacuation maps - Detailed task-by-task plans for: - Evacuation - Fire in a Process or Non-Process Area - Injuries - Threats/Civil Disorder - Wildland or Adjacent Property Fire - External Events (e.g., seismic) - Potential Imminent Danger to Personnel - Chemical Spill (e.g., caustic, aqueous ammonia) - Chlorine Release - Off-Site Event Involving a Hazardous Material IRWD maintains a safety committee whose members are the designated emergency coordinators for the facility. IRWD has 26 employees that are specialists, trained and fully equipped to handle hazardous spill containment and cle anup. These employees train monthly and run drills twice a year. The Emergency Response Plan provides the response organization and notification procedures, evacuation routes, chlorine health hazards, and mitigation procedures, which will be implemented to respond effectively to emergency situations that may arise at the facility. This Plan is reviewed and updated at least once per year. This Plan has been reviewed and updated to ensure compliance with the PSM, RMP, and CalARP regulations Stationary Source and Regulated Substance The chlorine system at Irvine Ranch Water District's Rattlesnake Reservoir Facility is used for the treatment of recycled water from the reservoir. This is an unmanned facility. An operator visits the site at least once per week. If maintenance on the chlorine is required, two operators/maintenance personnel are present. Chlorine is stored in one-ton containers (9) in the chlorine storage room. Chlorine gas leaving the one ton containers passes thro ugh a vacuum regulator to the chlorinator. Still under vacuum from the chlorinator, it is drawn to injectors and mixed with water from the reservoir. The chlorine solution is delivered to various locations. The chlorine storage room has two independent manifold systems connected to a common header that feed into the chlorine system. Three chlorine containers are connected to each manifold system. One manifold is active and the other is kept in stand-by status. Chlorine gas is drawn from the one-ton containers through a vacuum regulator to the chlorinators. Still under vacuum from the chlorinator, it is drawn to an injector and mixed with water from the reservoir. Tanks are replaced in groups of three when one side of the distribution system becomes empty. Irvine Ranch Water District operators use a monorail hoist to do this replacement. Each container is positioned so that the valves are vertically aligned. A vacuum regulator is connected to the top valve of each one ton con tainer to ensure that chlorine gas is drawn out of the container. A vacuum is created when process water is pumped through the injectors. This flow generates a vacuum (approximately 1-3 in. Hg) which opens the vacuum regulator. Upon loss of vacuum in the line from any one ton container, a diaphragm in the vacuum regulator will close, stopping any chlorine from escaping. Any chlorine in the piping upon loss of vacuum will be drawn through the chlorinators and into solution. As the on-line side of the manifold becomes empty, the system automatically switches over to the containers in the stand-by mode. This ensures that chlorine is available. The maximum quantity of chlorine that can be stored on site is 18,000 pounds - 9 one ton containers. Hazard Assessment Summary Worst Case Release Result Summary Scenario Description: Release of the maximum quantity of chlorine that can be stored in the largest vessel - 2,000 pounds in 10 minutes. The containers are stored inside a buildin g; however, during delivery, the truck is positioned outside the building. The side doors are open and the monorail hoist extends outside to the vehicle to unload the containers; therefore, passive mitigation measures were not incorporated in the release rate calculations. The most pessimistic meteorological conditions were used as specified in the regulation. The reference table included in EPA's RMP Guidance for Wastewater Treatment Plants was used to determine the maximum downwind distance to 3 ppm. The result shows that offsite areas may be affected. Alternative Release Result Summary Scenario Description: A release of chlorine gas from 1/4-inch diameter leak until the container is empty (2,000 pounds). The release rate is based on the pressure within the three ton containers, hole or puncture area in the pipe, tank temperature, and a gas factor, which incorporates a discharge coefficient, ratio of specific heats, molecular weight, and conversion factors. The containers are located inside; therefore, the enclosure was incorporated into the release rate calculation as a mitigation measure. This scenario was proposed to last for one hour. This is based on the fact that there is a chlorine detector in the storage room would alarm at the main office via the SCADA system and an emergency response team trained to repair leaks and/or install a B-kit which will contain a release at the cylinder valve. The meteorological conditions specified in the regulation for alternative scenarios were used. The reference table included in EPA's RMP Guidance for Wastewater Treatment Plants was used to determine the maximum downwind distance to 3 ppm. The downwind distance for this scenario is significantly less than that for the worst case scenario. However, in this case also offsite areas may be affected. Accidental Release Prevention Program and Chemical-Specific Prevention Steps IRWD has a Process Safety Management program in place to manage the handling of chlorine . In addition, common industry standards, policies, and procedures are utilized to ensure safe practices are being performed. This includes common practices outlined by the Chlorine Institute. In addition to the Management Programs, there is a chlorine leak detector situated in each room (storage and feed). In the event of a chlorine leak that reaches a concentration of 1ppm, in either the chlorine storage room or the feed room by the sensors, a red alarm light outside the affected room is illuminated and an audible beacon is turned on. The SCADA system alerts personnel at IRWD's main control room of this detection. Five Year Accident History There have been no reportable releases of chlorine at the facility during the five year perios of June 1994 through June 1999. Planned Changes to Improve Safety Several studies have been conducted recently to examine mitigation measures to improve safety at the Irvine Ranch Water District Initial Disinfection Facility. These studies in clude the following: Process Hazard Analysis, Seismic Assessment, Hazard Assessment, and PSM Compliance Audit. The recommendations from these studies will be completed by January 1, 2000. Some of the recommendations are listed below. 1. Verify the SOP operators use while connecting containers to the system includes a statement that reads "containers are vertically aligned." 2. Develop an inspection sheet for the crane/hoist that the operators must complete before crane usage. 3. Include in ton container receiving procedure a statement to use crane checklist. 4. Include in the training program a requirement to document each training and have both supervisor and trainee sign completion forms. 5. Consider using an outside agency to train operators. 6. Post arrow signs on piping to indicate the flow of chlorine. 7. Provide a sign that reads "Chlorine" outside of the main doorway. 8. Investigate whether or not a second door can be opened from the inside of the building in ca se an operator has to escape. |