Los Alisos Water District Reclamation Plant - Executive Summary

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ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES 
 
Los Alisos Water District has an emergency response plan in effect.  The Emergency Response Plan (Plan) is detailed in the Emergency Planning and Response section of the Los Alisos Water District's PSM/RMP document.  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. 
 
Los Alisos Water District maintains a safety committee whose members are the designated emergency coordinators for the facility.  The 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 was reviewed and updated to ensure compliance with the PSM, RMP, and CalARP regulations, and  
to ensure that the plan is kept current. 
 
 
STATIONARY SOURCE AND REGULATED SUBSTANCE 
 
Startup of the chlorine system occurred in 1965.  The process is located at 22312 Muirlands Blvd., Lake Forest, California 92630.  The chlorine system for Los Alisos Water District consists of chlorine one-ton containers which are the storage vessels.  Chlorine gas is drawn from a maximum of three tanks at a time through a vacuum regulator to the chlorinators.  Still under vacuum from the chlorinators, it is drawn to injectors and mixed with water from the treatment processes. The maximum quantity of chlorine that can be stored on site is 36,600 pounds. 
 
 
HAZARD ASSESSMENT SUMMARY 
 
Worst Case Release Result Summary 
Scenario Description: Release of the maximum quantity of chlorine that can be stored in a vessel - 6,000 pounds (due to a maximum of three one-ton containers connected to a manifold at any given time) in 10 minutes.  The tanks are stored enclosed in a building, therefore, passive mitigation 
measures were used.  The most pessimistic meteorological conditions were used: 1.5 meters/second wind speed, and F stability.  The EPA's RMP Guidance for Wastewater Treatment Plants were used to determine the distance to the toxic endpoint of 3 ppm.  This scenario reaches off-site and may affect population receptors.  No environmental receptors were affected by this potential scenario. 
 
Alternative Release Result Summary 
Scenario Description: A release of chlorine gas from 1/4 inch diameter leak.  The release rate of chlorine due to the pressure of the tank is 10.1 pounds per minute.  However, active and passive mitigation measures were incorporated since a scrubber system is designed to pull contaminated chlorine gas from the room to be neutralized and recycle the air back into the building.  Consequently, the release rate after these measures was calculated to be 3.2 pounds per minute.  The meteorological conditions used were 3 meters per second wind speed, and D stability.  The EPA 
's RMP Guidance for Wastewater Treatment Plants were used to determine the distance to the toxic endpoint of 3 ppm.   This scenario reaches off-site and may affect population receptors.  No environmental receptors were affected by this potential scenario. 
 
 
ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL-SPECIFIC PREVENTION STEPS 
 
Los Alisos Water District 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.  The Los Alisos Water District maintains tight control of its chlorine process through various process controls and monitors.  In the event that the primary engineering or administration controls at the facility fail and result in a release of chlorine, there are three mechanisms in the plant to minimize the impact:  1) chlorine sensors, 2) alarms, and 3) a  
scrubber system.  Chlorine sensors located inside the chlorine building trigger an audible and visual alarm located outside the chlorine tank building and chlorinator room.  Once a chlorine concentration of 1 ppm is detected within the chlorine building by the sensor, beacons located outside the doorways of these rooms are activated.  In case of a chlorine leak in the tank storage room, the detector automatically triggers a scrubber system that pumps a sodium hydroxide/water solution and introduces it to the chlorine gas that has been removed from the room.  The gas is neutralized by contact with the scrubber solution and is re-introduced back into the tank room.  The four louvered exhaust vents located in the tank room and one in the chlorinator room close and remain closed for the duration of the scrubber cycle.  The alarm has telemetry to the main control room which will page the operator on duty. 
 
 
FIVE YEAR ACCIDENT HISTORY 
 
There has been one reportable release of chlorine at the 
facility.  A chlorine gas leak occurred at 10:35am in the chlorine building on April 21, 1998.  The leak originated as the pigtail was disconnected from a problematic valve thought to be closed.  The leak was detected by the chlorine sensor and the scrubber system was activated.  An alarm signal was sent to the telemetry system.   
 
The Fire Department arrived to the scene where a Los Alisos Water Distirct response team implemented a plan to contain the leak.  The leak was isolated within seven minutes and no injuries were reported.  Approximately 15 pounds of chlorine gas had leaked into the room which the scrubber neutralized.  A staff meeting was held to generate future suggestions for areas of weakness or changes needed to operational procedures. 
 
 
EMERGENCY RESPONSE PROGRAM 
 
Los Alisos Water District Reclamation Plant has twelve operators who have 24 hour HAZWOPER Hazardous Materials Technician level training.  If a release of chlorine were to occur at the Reclamation Plant, those 
trained operators will respond to stop the leak.  Two operators are also 8 hour HAZWOPER trained for Operations Level who are responsible for calling 911 in order to contact the Orange County Fire Department/HazMat team.  The Orange County Fire Department HazMat Team will be responsible for aiding in evacuation if necessary.  Drills have been performed during the HAZWOPER training.  The latest drill was performed on May 27, 1999.  Annual refresher training will occur as required by the HAZWOPER certification.   
 
The emergency response plan provides the response organization and notification procedures, evacuation routes, and mitigation procedures which will be implemented to respond effectively to emergency situations that may arise at the facility.  This plan was reviewed and updated to ensure compliance with the PSM, RMP, and CalARP regulations.  It is revised annually to ensure that the plan is kept current. 
 
 
PLANNED CHANGES TO IMPROVE SAFETY 
 
The Process Hazard Analysis (PHA) pro 
vided the mitigation measures outlined below to improve safety at the Los Alisos Water District Reclamation Plant.  The PHA was comprised of one session that included a HAZOP study, a Plant Walkthrough, a "What-if" analysis, and a series of checklists.  Changes were made to improve safety and were complete by May 27, 1999.  
 
A Seismic Assessment was conducted and found that chlorine piping was adequately supported with all attachment and anchorage in good condition.  There were no signs of damage or corrosion.  Floor drains empty into the adjacent storage pond and should present no danger during a chlorine spill.
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