Michelson Water Reclamation Plant - Executive Summary

| Accident History | Chemicals | Emergency Response | Registration | Source | 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 cleanup. These employ 
ees 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 
There is a single chlorination building located at the Irvine Ranch Water District Michelson Water Reclamation Plant. The chlorine storage room contains a 50,000-pound bulk chlorine storage tank.  This tank is refilled and maintained by the bulk chlorine supplier, DX Systems.  The chlorine is used to disinfect wastewater. 
Chlorine gas is supplied under pressure to two 8,000 pound per day chlorinators which regulate the chlorine feed rate.  A vacuum is created at the chl 
orinators by water flow through an aspirator type injector.  The chlorinators are equipped with electric heaters to reduce the deposit of impurities and to prevent liquefaction of the gas when the chlorinator shuts down during normal operations. 
The maximum quantity of chlorine that can be stored on site is 50,000 pounds. 
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 - 50,000 pounds in 10 minutes.  The container is located in a building;  therefore, this passive mitigation measure was incorporated in the 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: The 
alternative release scenario represents a severe event that is more likely to occur than the worst case scenario.  The alternative scenario at MWRP is based on the release that occurred on January 21, 1998 (see Five-Year Accident History).  The estimated quantity released during that incident was predicted to be 1 - 2 pounds and there were no off-site incidents; therefore, this scenario was expanded to a 0.25" leak that lasted for 30 minutes, hence releasing a larger quantity to the atmosphere resulting in off-site impacts. 
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 substantially 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 Preve 
ntion 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 are chlorine leak detectors situated in all rooms that contain chlorine (4 total).  In the event of a chlorine gas leak reaching 0.5 ppm, the detectors relay a signal that activates a horn and a light outside the room where chlorine has been detected.  In addition, the alarm is displayed on the SCADA monitors.  Finally, at 1 ppm, the alarm signal is routed to the phone dialer system, WIN 911, where the pagers are alarmed 
Five Year Accident History 
The five-year accident history (March 1994 through March 1999) for the MWRP reveals that there was one incident that involved a release of chlorine from the regulated process and caused on-site injuries 
.  This incident occurred on January 21, 1998 at 12:20 p.m. and lasted approximately one minute. 
The release occurred during the delivery of bulk chlorine from the delivery truck to the storage tank.  Towards the end of the delivery, the pressures in both vessels started to equalize; therefore, it was decided to start the compressor to pump the remaining chlorine into the storage tank.  When the compressor was started, a small amount of liquid chlorine escaped through the hose connection on the discharge side of the compressor.  The delivery driver closed the isolation valve on the suction side of the compressor and shut down the compressor to immediately stop the leak.  The liquid chlorine vaporized and became airborne. There were seven contract employees working on the roof of the chlorine building who inhaled chlorine.   
It was concluded that approximately 1 - 2 pounds of chlorine were released because the delivery driver did not examine the compressor discharge piping to ensure t 
hat a gasket had been installed.   
The seven contract employees were examined as a precaution and found no injuries. 
No off-site impacts were reported. 
Orange County Fire Authority and the State Office of Emergency Services were contacted following the release; however, no emergency responders were required or contacted during the release. 
Mitigation Measures:   
1. The chlorine delivery checklist was modified to make sure that the driver examines the compressor piping properly. 
2. IRWD personnel will enforce the use of a checklist. 
3. No one will be allowed in the area during the entire fill/delivery procedure. 
The incident was discussed during the morning operators meeting on January 22, 1998 and the incident was further discussed at a general meeting with Department 51, 52, 53, 54, and 55 employees. 
No weather conditions were documented. 
Planned Changes to Improve Safety 
IRWD is taking additional steps to further public safety.  Several studies have been conducted recently t 
o examine mitigation measures and additional steps to further ensure public safety at the IRWD, Michelson Water Reclamation Plant.  IRWD is currently examining the feasibility of a scrubber system and new piping for the bulk chlorine delivery process.  It is expected that the new scrubber system will be designed by February 2000 with installation to follow.
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