Ebbetts Pass (Hunters) Water Treatment Plant - Executive Summary

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1. Accidental Release Prevention and Emergency Response Policies  
The Calaveras County Water District's Ebbetts Pass (Hunters) Water Treatment Plant (WTP) located at 335 Hunters Dam Road in Hathaway Pines, California, uses chlorine, which is a hazardous material and regulated substance, that is considered in the Risk Management Plan (RMP).  The properties of chlorine make it necessary to observe safety precautions in handling chlorine to prevent human exposure, and to reduce the threat to the facility's workers and nearby members of the community. It is the facility's policy to adhere to all applicable Federal and State rules and regulations.  Safety depends upon the safe procedures used to handle chlorine, the safety devices and systems designed and constructed into the facility; and the training of the pertinent personnel. 
2. Stationary Source and Regulated Substances Handled 
The WTP is designed to treat water to disinfect the effluent against harmful pathogenic 
Chlorine is delivered to the WTP by a commercial supplier in one ton containers for use at the WTP. Off-loading of the one ton containers from the commercial delivery vehicle is accomplished by the use of a hoist and lifting bar.  Two of the one ton containers are on a cradle with trunnions and a load scale. One of the one ton containers is connected on-line and the other one ton container is connected and on stand-by.  No one ton containers are in storage. 
The WTP has administrative procedures in place to limit the amount of chlorine at the facility to no more than two of the one ton containers.  Delivery of the one ton containers is during normal working hours. The driveway provides adequate room for the delivery and parking of the delivery vehicles during the off-loading of the full one ton containers, and the loading of the empty one ton containerts. 
The chlorine building is locked after normal working hours and the area is fenced.  No unauthorized personnel are allow 
ed entry into the chlorine building. The container storage and handling is conducted pursuant to per Sections 2.6, 2.7, and 2.8 of the Chlorine Institute's Chlorine Manual. 
The WTP operates twenty four hours per day, seven day a week.  The chlorine gas is withdrawn from the one ton containers by vacuum.  This vacuum is created by an injector.  This vacuum opens the vacuum regulator diaphragm, and withdraws gas from the one ton containers at a controlled feed rate.  The chlorine gas is injected into the feed water line, where it becomes a chlorine/water solution and is feed where it is needed in the treatment process.  The container storage room has an exhaust system, leak detector, and alarm systems. Each chlorinator is vented to the outside if their diaphragm malfunctions. 
3a. Worst Case Release Scenario 
The Worst Case release scenario must consider the largest quantity of a regulated substance handled on site in a single vessel at any time, taking into account administrative contr 
ols on the vessel's contents and usage as per 40 CFR Part 68 Section 68.25.  The one ton container of chlorine is the largest vessel in the treatment system and has 2,000 lbs. of liquid chlorine. The Worst Case release scenario for the one ton container of chlorine is the release of chlorine at the rate of 200 lbs/min for 10 minutes.  The distance to the endpoint for the Worst Case scenario will extend beyond the boundaries of the stationary source. 
3b. Alternative Release Scenario 
The Alternative Release scenario for the one-ton container of chlorine is a leak occurring in the 
packing material around the gas valve stem of the valve on the one ton container.  There are no active or passive mitigation measures that are considered to reduce the amount of chlorine released or treatment system to which released chlorine would be directed and treated.  It is assumed that the release of 2 lb/min would continue for a period of sixty minutes. During that the time a total of 120 pounds of chl 
orine would be released. In this scenario, the distance to the endpoint would extend beyond the boundaries of the stationary source. 
3c. Administrative Controls 
Administrative controls exist to restrict to a minimum, the amount of chlorine lost from a one ton container if accidental release were to occur. This administrative control is inherent in the operational procedures for the chlorine process system and the training provided of the operators of the process system. 
3d. Mitigation Measures 
Mitigation measures to limit the distances for each reported scenario exist to restrict the amount of chlorine released to a minimum if a release were to occur. The mitigation measures are based upon the design, inspection, testing, and maintenance of the chlorine process systems; their related equipment and components. 
4. General Accidental Release Prevention Program and Chemical Specific Prevention Steps 
The facility complies with all applicable federal and state codes and regulations. Th 
ere are safety meetings and safety training.  The Process Safety Management (PSM.) program implemented at the facility for the chlorine process system and the related activities and equipment represents the facility's main active commitments to an accidental prevention program. 
5. Five Year Accident History 
There has been no accidental release of chlorine in the last five years. 
6. Emergency Response Program 
The Emergency Response Program is based upon alerting personnel at the facility to evacuate the facility and await the arrival of responders from the Fire Department at the evacuation assembly location if a release occurs that causes the evacuation to be initiated.  The Calaveras County Environmental Health can incorporate this response into the Area Plan for the Local Emergency Planning Committee. 
7. Planned Changes to Improve Safety 
There are commitments under the Hazard Review that are planned to be implemented.  Current applicable codes and regulations are reviewed to det 
ermine if other commitments need to be made to achieve increased operational safety for the regulated chlorine process system.  These commitments will be prevention and mitigation measures for the accidental releases of the regulated substance.
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