Calleguas MWD Lake Bard Water Filtration Plant - Executive Summary
The Calleguas Municipal Water District Board of Directors, management and all employees are committed to the safe operation of the Lake Bard Water Filtration Plant. This commitment is reflected in the design, operation, maintenance, and procedures used to operate the plant. Calleguas has used chlorine gas safely at this facility since 1964. The focus of Calleguas policies are to operate and maintain the chlorine disinfection system of the Lake Bard Water Filtration Plant in such a way as to protect Calleguas employees, the surrounding communities and the environment from a chlorine leak. The policies incorporate the highest level of commitment to establishing safety by insuring multiple, redundant and parallel layers of safety. The equipment is engineered for safety, procedures are developed for safe operation, safety is incorporated into training, employees are provided personal protective equipment, and emergency response procedures are coordinated with the local responding agenc |
Calleguas Municipal Water District uses and stores only one regulated substance. Chlorine gas is the single regulated substance requiring the development of the Risk Management Plan. The maximum quantity capable of being stored on site is 40,000 lbs. However, the maximum quantity normally stored on site seldom exceeds 30,000 lbs. The chlorine gas is stored and used directly from Department of Transportation certified one (1)-ton cylinders.
Worse case and alternate case scenario analysis
The worse case scenario involves the release, within ten minutes, of one cylinder containing 2000 lbs. of chlorine gas, liquefied under pressure. This scenario assumes that the release occurs inside the concrete storage building without mitigation by the scrubber. Based upon this worse case scenario the area of toxic concern will extend out from the storage building and would impact the surrounding communities. The alternate release scenario involves a more reali
stic release mitigated by physical and mechanical means. This scenario assumes a full 2000 lb. cylinder is released. However, the release of the cylinder is mitigated by both being confined by the building and absorbed by the chlorine scrubber. The design criterion for the scrubber is to absorb and neutralize 99.998 % of the chlorine gas resulting in a release of less than .4 gal of chlorine gas. The area of toxic concern in this scenario would extend less than one-tenth of a mile around the storage building. This release would not extend beyond the confines of the Calleguas property and would have little or no impact on the surrounding communities.
Administrative control and mitigation measures
Calleguas Staff, in conjunction with design engineers have developed a series of operational, and maintenance checklists and procedures. These procedures insure the proper operation of the chlorine system. In addition, these procedures insure that the equipment is calibrated, inspected
and maintained at the top of safe operational efficiency.
The system is designed to prevent the release of chlorine by including layers of safety. The chlorine is stored in a concrete building, located away from and remotely monitored by the 24-hour operations center. The chlorine storage building has automated valves that will close if a chlorine leak is detected. The building has a scrubber incorporated into the design of the building. The scrubber is designed to absorb and neutralize approximately 3000 lbs of chlorine gas (1.5 full cylinders). Distribution of the chlorine gas outside of the scrubber protected building is through buried vacuum pipelines designed to stop the flow of gas if a break occurs in any pipe.
Prevention program and chemical specific prevention steps
The prevention program includes the full range of preparation and chemical specific measures available to prevent and prepare for an incident. All information concerning chlorine and the detailed engineer
ing design information has been consolidated and is available. An independent engineering consultant has completed the process hazard analysis. They have reported that, "The facility was found to be well designed with many safety systems in place to prevent and/or mitigate potential chlorine releases."
5 year accident history
Since 1964, Calleguas has used chlorine gas as a disinfectant for the water treatment proces.; Calleguas has never had an accident having offsite consequences. Within the last five years Calleguas has not had an accident involving chlorine gas at this facility.
Emergency response program
Calleguas has a very active emergency response program. Calleguas is an active member of the Ventura County Community Awareness and Emergency Response (CAER) Group. Through this organization we actively participate with the local Hazardous Materials Response Teams to prepare for emergencies at our facility and provide resources for emergency responses throughout the c
ounty. Together with the local emergency responders, we have had full-scale exercises at our facility to prepare and familiarize the planned responding units with our facility. These exercises have resulted in the emergency response groups having planned and prepared for an incident at our facility.
Changes planned to improve safety
All changes recommended by the Process Hazard Analysis and Seismic review were minor in scope and will require only slight modifications to procedures, or coordinating the alarm set points for the chlorine alarms or fire alarm systems. All procedural changes will be completed by October 1999.