Town of Windsor Wastewater Treatment Plant - Executive Summary
FEDERALLY MANDATED RMP SUBMISSION
1. Accidental Release Prevention and Emergency Response Policies
This Town of Windsor Wastewater Treatment Plant, located at 8400 Windsor Road in Windsor, CA, handles chlorine, which is considered a hazardous material that is a regulated substance and is considered in the Risk Management Plan (RMP). The properties of chlorine make it necessary to observe safety precautions in handling 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 of California 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 Town of Windsor uses chlorine gas to disinfect wastewater in the WWTP. Chlorinatio
n facilities include the chlorination building, distribution piping, mixer/induction units, and the chlorine contact tanks. The chlorination building houses the chlorinators and the chorine cylinder storage. The treatment plant occupies a 74-acre site and two branches of Windsor Creek pass through the treatment facilities.
Chlorine is delivered by a commercial chlorine supplier in five one-ton containers for use at the WWTP. Delivery of the one-ton containers occurs 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 loading of the empty one-ton containers. The chlorine building is not exposed to vehicular traffic. The chlorine building is locked after normal working hours. No unauthorized personnel are allowed entry into the building. The container storage and handling is conducted pursuant to per Sections 2.6, 2.7, and 2.8 of the Chlorine Institute's Chl
The chlorine gas is withdrawn from the one-ton containers by vacuum. This vacuum opens the vacuum regulator diaphragm and withdraws the chlorine gas from the one-ton containers at a controlled feed rate set by the operators with the use of the rotometer at the chlorinator unit. The 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 chlorine building has inlet and outlet exhaust fans for fresh air entry, chlorine leak detectors, and alarm systems. The vacuum regulators are vented to the outside.
The receipt, storage, and handling of the subject substances are considered as part of one complete process.
3a. Worst Case Release Scenario
The one ton (2,000 pounds) chlorine container is the largest vessel in the chlorine system located at the Windsor WWTP. The Worst Case release scenario to be modeled for the one ton chlorine container assumes that the full 2,000 poun
ds of chlorine is released over a ten minute period resulting in a release rate of 200 pounds per minute. The distance to the endpoint of .0087 mg/l for the Worst Case scenario is 1.3 miles. This chlorine release will extend beyond the boundaries of the stationary source.
3b. Alternative Release Scenario
The Alternative Release scenario for chlorine for the one ton container located at the Wastewater Treatment Facility assumes a release from a valve packing, resulting in an estimated release of no more than 2 pounds per hour. The period of release is taken to be one hour in duration, resulting in a total release quantity of 2 pounds for the regulated substance. The distance to the endpoint of .0087 mg/l for the Alternative Release scenario is 0.1 mile. This chlorine release will extend beyond the boundaries of the stationary source.
3c. Administrative Controls
Administrative controls to limit the distances for each reported scenario exists to restrict to a minimum the amoun
t of chlorine released, if a release were to occur, and preferably to not have a release occur. This administrative control is inherent in the operational procedures for the chlorine systems and the training provided to the chlorine operators.
3d. Mitigation Measures
Mitigation measures to limit the distances for each reported scenario exists to restrict to a minimum the amount of chlorine released, if a release were to occur, and preferably to not have a release occur. The mitigation measures are based upon the design, inspection, testing, and maintenance of the chlorine system and its 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. There are safety meetings and safety training. The Process Safety Management (PSM) program implemented at the facility for the chlorine related activities and equipment represents one of the f
acility's main active commitments to an accidental release prevention program.
5. Five Year Accident History
There have been no incidents involving the release of chlorine within the past five years at the facility.
6. Emergency Response Program
The Emergency Response Program is based on alerting personnel at the facility of the need to evacuate the facility and await the arrival of responders from the Town of Windsor Fire Department at the evacuation assembly location if a release occurs that causes the evacuation to be initiated. The Sonoma County Division of Environmental Health Services incorporates this response into the County Area Plan for the Local Emergency Planning Commission.
7. Planned Changes to Improve Safety
There are commitments made under the Process Hazard Analysis element of the Process Safety Management (PSM) that are being implemented at this time for the next year.
Current applicable codes and regulations are reviewed as part of the PSM to determine if ot
her commitments need to be made to achieve increased operational safety for the regulated chlorine system. These commitments will be prevention and mitigation measures for accidental releases of the regulated substances.