Travis A.F.B. Water Treatment Plant - Executive Summary

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The City of Vallejo is required to develop and implement a Risk Management Program (RMP) for the Travis A.F.B. Water Treatment Plant under U.S. EPA RMP regulations and California Accidental Release Prevention (CalARP) Program regulations due to the facility's use and storage of up to 8,000 pounds of chlorine.  The RMP is subject to Program 3 guidelines because the worst-case release scenario endpoint distance for chlorine exceeds the distance to the nearest public receptor and the quantity of chlorine utilized is sufficient to make the facility subject to the Process Safety Management (PSM) regulations administered by U.S. OSHA.  The facility's RMP consists of an offsite consequence analysis based on the U.S. EPA guidance document  and computational modeling, procedures for accidental release reporting, a prevention program, and an emergency response program. 
 
Chlorine is added to surface water and well water treated at the facility in order to ensure purity of the drinking water and t 
o meet California Department of Health Surfaces water treatment regulations by accomplishing the disinfection of any pathogens that might be present in the water supply.  The present chlorination system installed at Travis A.F.B. Water Treatment Plant was designed in 1992 by Kennedy/Jenks/Chilton in accordance with recognized and generally accepted good engineering practices, federal, state, and local design regulations and codes, and industry-specific design codes and standards.  The system is designed such that all chlorine is conveyed from the storage cylinders under vacuum pressure created by water flowing through an injector.  This design greatly enhances the overall safety of the system because regulator valves will not permit chlorine to be conveyed if the vacuum is lost, as would be the case under most possible failure scenarios.   
 
At most two one-ton chlorine cylinders can be connected to the chlorination system at a time.  Up to two additional one-ton cylinders may be stored 
in the chlorine room, making the maximum total chlorine inventory 8,000 pounds.   
 
As a safeguard against the consequences that may occur due to a chlorine release, a chlorine vapor recovery system is installed that is designed to prevent a significant release of chlorine to the atmosphere.  The vapor recovery system automatically activates when a chlorine leak is detected (>1 ppm), and will remain activated until the detector senses an acceptable vapor level within the Chlorine Feed Building.  The system is rated to reduce the chlorine concentration of air released to the atmosphere such that ground-level chlorine concentrations will not exceed 3 ppm, the level of concern used for the offsite consequence analysis of the RMP. 
 
In general, two operators are on-duty at the Plant during the day, and one at night.  In addition, as a condition of employment, the City requires that the Senior Treatment Plant Operator appointed to the Travis Plant live in an onsite residence.  This arrangeme 
nt provides a round-the-clock superintendence of the plant at all times that the senior operator is on the premises.  It also affords an round-the-clock on-site management which results in timely assessments and responses to problems ranging from correcting process problems to the prevention or suppression of hazardous conditions. 
 
A Process Hazard Analysis (PHA) was conducted for the Travis A.F.B. Water Treatment Plant as part of developing the facility's PSM.  The PHA is an organized and systematic effort to identify and analyze the significance of potential hazards associated with the processing or handling of highly hazardous chemicals.  The PHA focuses on equipment, instrumentation, utilities, human actions (routine and non-routine), and external factors that might impact the process.  These considerations assist in determining the hazards and potential failure points or failure modes of a process.  When hazard scenarios are identified, existing or proposed designs and operations  
are assessed to determine if appropriate engineering and administrative controls are in place.  If the current level of protection is determined insufficient, recommendations are made to eliminate and mitigate the scenarios. 
 
In order to provide a thorough analysis as specific as possible to the Travis A.F.B. Water Treatment Plant, the Hazards and Operability Analysis (HazOp) method, incorporating the guide-word approach, was selected for the PHA.  The HazOp Study was conducted on May 5, 1999 by a HazOp Team consisting of two employees of Block Environmental Services, with expertise in the HazOp process, and eight members of the City's staff, with collective expertise in the engineering, management, operations, maintenance, and health and safety for the City's water treatment facilities.   
 
The PHA also included a seismic review to determine whether the facility and equipment are designed and installed sufficiently to withstand impacts from expected seismic events.  In addition, risks  
posed by the date change to the year 2000 (Y2K) and possible computer system complications were also assessed as part of the PHA.  Several other external events that might impact the chlorination system were also examined, including fire, power failure, sabotage, flooding, and tornado. 
 
In general, the HazOp team concluded that engineering controls, safety systems, and procedures in place at the facility achieve the lowest risk practicable for all deviations identified, based on the implementation of two recommended additions to the standard operating procedures, which is slated for July, 1999.  Because all flow of vapor chlorine in the system relies on vacuum pressure created by the chlorine injectors, releases from most anticipated failure scenarios will necessarily be limited because regulator valves will automatically close upon the loss of vacuum pressure that would accompany a release.  The type of release determined to pose the greatest risk is a breakage of the cylinder valve d 
uring cylinder changeover. 
 
The Assistant Water Superintendent is assigned overall responsibility for the development, implementation, and integration of the RMP elements.  In addition, a management system is in place for implementing specific elements of the RMP.  The Senior Treatment Plant Operator will implement most of these elements, although specific tasks may be delegated to facility operators and maintenance personnel. 
 
The offsite consequence analysis portion of the RMP involves developing and modeling a worst-case and an alternative theoretical release scenario to estimate the impact an accidental release may have on the public and environment in the surrounding area.  The worst-case release assumes that the maximum amount of chlorine ever held in a single vessel at the facility is released into the atmosphere during meteorological conditions least conducive to expedient dilution of the released gas.  It is intended as a basis of comparison with other facilities, but it is no 
t realistic to expect such a scenario to actually occur.  The alternative scenario was selected based on the PHA conducted for the facility.  It is both a more likely potential release scenario and of sufficient magnitude to reach receptors offsite.   For the alternative release scenario, more representative, site-specific average daily atmospheric conditions are assumed.  OCA data reported for the RMP is based on data provided in Risk Management Program Guidance for Wastewater Treatment Plants, published by U.S. EPA in October of 1998.  The toxic endpoint to be used for chlorine is 3 ppm, which is the maximum airborne concentration that most individuals could be exposed to for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms.  
 
The worst-case release is predicted to reach the toxic endpoint at a distance of 1.3 miles from the facility.  Although the width of the area affected by chlorine concentrations of this magnitude, or foo 
tprint, is limited and will only extend downwind from the source, a circle with a 1.3 mile radius is drawn to identify potential offsite impacts.  Using interpolation of 1990 census block group data, it is estimated that 3,500 people live within this radius.  There are five schools, one hospital, and 4 parks within this radius.  There are no environmental receptors within this distance. 
 
The alternative release scenario chosen was identified in the PHA as posing the greatest risk (i.e. highest likelihood of occurrence and severest consequences) out of several release scenarios considered.  It consists of a breakage of the cylinder valve during cylinder changeover due to an operator applying excessive force to the valve in attempting to open it.  The active mitigation provided by the vapor recovery system installed at the Plant must be ignored for the analysis because if it functions as designed, the release would not extend offsite above the endpoint, as required by the regulations.  T 
aking into account passive mitigation provided by the enclosure of the chlorine room, it is conservatively estimated that 13.3 pounds-per-minute of chlorine is released to the atmosphere over two minutes under such a scenario.  The endpoint for this release extends 0.1 miles from the facility.  Using interpolation of 1990 census block group data, it is estimated that 10 people live within this radius (the same method could not be used for the worst-case release due to its magnitude).  No public or environmental receptors are located within the alternative scenario endpoint distance. 
 
Identifying these potential receptors is only an indication that they could be adversely affected by such a release.  The likelihood, type, or severity of potential impacts on either public or environmental receptors is not assessed in the RMP.  Furthermore, it is not possible for the entire area within the endpoint circle to experience concentrations of chlorine above the endpoint value, as concentrations 
of chlorine will only exceed the endpoint within a relatively narrow, oval-shaped footprint.  It should also be reiterated that the vapor recovery system installed at the facility is designed to prevent chlorine from being released above concentrations that would create any offsite impacts, however its function had to be ignored for the OCA. 
 
The accidental release reporting section of the RMP gives the details and definitions for what must be reported in the event of a significant release of chlorine.  The facility has not had an accidental release of chlorine that resulted in on-site deaths, injuries, or significant property damage;  or known offsite deaths, injuries, property damage, environmental damage, evacuations, or sheltering in place in the past five years. 
 
The prevention program requirements for Program 3 RMPs are taken verbatim from applicable sections of the PSM regulations.  This is a result of U.S. EPA's recognition that measures taken to reduce and mitigate hazards t 
o facility workers will also serve the same purpose for the surrounding community and environment.  Thus, in order to eliminate redundancy, the PSM is  referenced in the RMP.  The PSM consists of several elements that contain or describe procedures that must be implemented on an ongoing basis, including chlorine and process safety information,  process hazard analysis, operating procedures, employee training, contractor qualification, pre-startup safety reviews, mechanical integrity of equipment, management of change, incident investigation, and injury and illness prevention.  
 
The intent of the Process Safety Information (PSI) section is to compile system information for use in conducting the Process Hazard Analysis and to help facility operators to identify and understand the hazards posed by those processes involving highly hazardous chemicals.   PSI must include information on the hazards of the highly hazardous chemicals used in the process, information on the technology of the pr 
ocess, and information on the equipment in the process.  This information must be kept up-to-date as process changes or upgrades are made.  It should also be made available to all employees and be included, as necessary, in employee training programs. 
 
The PSI for the facility includes a list of hazardous chemicals stored at the facility, and information on the hazards of chlorine and the chemistry of the chlorination process.  This is followed by information specific to the facility's chlorination system, including design codes and standards utilized, handling one-ton, chlorination system equipment and operation, detectors and alarms, safety systems, the computer control and monitoring system, fire protection, signage, and security. 
 
The purpose of the operating procedures portion of the PSM program is to develop, implement, and maintain clearly written, detailed procedures, guidelines, rules and practices for the safe operation of the chlorination process during all operating phases. 
 A copy of the operating procedures must be readily accessible to all employees who work on or near the chlorination system.  All employees involved in the daily operation and maintenance of the chlorination process should have a full understanding of every operating phase.  This is to include an overview of the process, principles of using chlorine for disinfection, operating characteristics of the components and the associated safety hazards, and the proper steps to be taken to execute all system-related tasks in a safe manner.   
 
Standard Operating Procedures (SOPs) have been developed that include procedures for handling chlorine, system startup, normal operations, addressing deviations from normal operating conditions, normal shutdown, maintenance of specific equipment, and emergencies.  The SOPs must be reviewed as often as necessary to assure that they reflect safe operating practices, including updates that result from changes in the facility, technology, and/or equipment.  Th 
ey should also be reviewed and certified annually, for which a form is provided in the PSM. 
 
All employees involved with the disinfection process must understand the safety and health hazards of the use of chlorine in the process.  Therefore, the City has developed a written training program for all employees involved in the operation, maintenance, and supervision of the chlorination system.  Each employee involved with disinfection system operation will, at a minimum, receive training in understanding MSDS's, routine chlorination system operation, emergency chlorination system operation, normal and emergency chlorine safety and handling procedures, and the individual's role in emergency response.  This program includes the identity of employees to be trained, the training program technical content, competency requirements, documentation requirements for demonstration of competence, schedule for initial training and refresher training, and training for change.  In addition, contract an 
d maintenance personnel also receive training as provided for in the Contractor Qualification Program.  The PSM includes a form for documenting all training provided to employees. 
 
The purpose of the Contractor Qualification Program is to help ensure that contractors and their employees are fully aware of the potential dangers involved in the use of chlorine and the disinfection system.  This awareness should lead to reduced risk of accidents, and thus improved safety for both contractor employees and the company's employees.  It applies to all contractors performing any type of work (e.g. maintenance, renovation) on or in the vicinity of the chlorination system.  The Contractor Qualification Program consists of a five part procedure to be used during the procurement of a contractor in order to verify that their employees are adequately informed and trained, and includes several forms to facilitate and document the process.   
 
The purpose for the pre-startup safety review is to help en 
sure that certain important considerations have been addressed prior to startup of a new or modified process involving chlorine.  Pre-startup safety reviews are required for all new facilities and for all modifications that result in a change to the process safety information.  The PSM includes a procedure and documentation form for conducting the pre-startup safety review.  The review consists of verifying that all written process safety information is updated, that the requirements for Management of Change have been completed, that all safety, operating, maintenance and emergency procedures are updated, implemented, and adequate, that construction and new equipment is in accordance with the design specifications, and that training for each employee involved in operating or maintaining the new equipment in the process has been completed. 
 
It is essential to maintain the mechanical integrity of critical process equipment to ensure it is designed and installed correctly, and operates pr 
operly.  The mechanical integrity program has been developed to help ensure that all equipment used to process, store and handle chlorine is maintained properly.  The mechanical integrity program includes an inventory of all chlorination system equipment, including the date on which it was installed and its life expectancy, a description of the City's maintenance program, including scheduled maintenance tasks and inspections.  
 
Maintenance of the chlorination system is conducted on a daily, weekly, monthly, semi-annual, annual, and as-needed basis.  Maintenance task and schedules predominantly consist of preventative measures.  Administration of the maintenance program is computer-based, with Hanson software providing preventative maintenance, spare parts inventory, and work order tracking, as well as records, reports, and cost accounting for the City's water facilities. 
 
A PSM compliance audit must be completed at least every three years.  The principal objective of the audit is deter 
mine whether the procedures and practices that have been developed to comply with the PSM regulation are adequate and are being followed.  The audit is to include an evaluation of the design and effectiveness of the PSM program and a field inspection of the safety and health conditions and practices to verify that the PSM elements are effectively implemented.  
The Assistant Water Superintendent will select a trained individual or assemble a trained team of people to audit the PSM program.  The audit should include a review of the relevant documentation and process safety information, an inspection of the facility, and interviews with all levels of facility personnel.  The PSM includes forms to facilitate and document the compliance audit. 
 
Any facility or process is continually undergoing change in order to improve the efficiency, operability, or safety of the operation, or to replace mechanical equipment.  In order to facilitate necessary changes, while ensuring that unrecognized and/ 
or unacceptable hazards are not introduced, the management of change (MOC) procedure has been developed.  The objective of the MOC procedure is to help ensure that all changes are properly reviewed, and that any hazards introduced by the implementation of the change are identified and controlled, prior to placing the change in operation.  The MOC procedure is intended to apply to all equipment and procedures involving the chlorination system, and to any change in procedures regardless of whether the change is considered major or minor, or is of a temporary or permanent nature.  As part of the PSM, definitions, procedures, and documentation forms were developed to accomplish the MOC. 
 
A procedure has been developed to investigate serious incidents or near-misses in order to understand what happened (or could have happened) and to prevent any recurrence of similar incidents, thereby improving the safety of the process.  A formal incident investigation will be performed any time there is  
an incident which resulted in, or which could reasonably have resulted in (near-miss), a catastrophic release of chlorine.   The PSM includes procedures and forms for conducting and documenting an incident investigation for a release of chlorine, which supplement procedures included in the facility's Injury and Illness Prevention Plan.  The procedures include initial incident response, establishing an investigation team, determining the facts, determining the cause, recommending corrective and preventive actions, communicating the results, and follow-up. 
 
California mandates that the facility develop an Injury and Illness Prevention Program (IIPP).  The IIPP is designed to prevent accidents and to reduce personal injury and occupational illnesses for all employees.  The IIPP accomplishes this by developing procedures to identify hazardous workplace conditions, followed by the implementation of controls, procedures, and work practices to insure that these hazards have been properly iden 
tified and corrected.  Portions of the IIPP that cover the use of hazardous materials (i.e. Communication, Inspections, Training, etc.) have been integrated into the PSM to ensure consistency and eliminate redundancy and overlap between the documents. 
 
The City has developed two documents that comprise the Emergency Response Program (ERP) for the facility.  The Emergency Response Plan was developed to meet the requirements of several applicable federal and state regulations in one comprehensive document.  It includes procedures for informing the public and offsite emergency response agencies of a release, proper first aid and emergency medical treatment for employees, first responders, and members of the public who may have been exposed to a release of hazardous substance, and hazardous material leak emergency response procedures including descriptions of the actions to be taken by employees and other individuals on-site over the entire course of the release event.  Included in the Pla 
n is a site map with evacuation routes, which is also conspicuously posted at pertinent location throughout the facility. 
 
The Emergency Response Procedures, included in the Facility Operations Plan, provide procedures and contingencies for several kinds of emergencies and process upsets.  Also included is a Water Quality Emergency Notification Plan to be utilized when an imminent danger to the health of water customers exists.  
 
The ERP also includes maintenance and inspection procedures for emergency response equipment and emergency response training for employees, which are found in the mechanical integrity and training program sections of the PSM. 
 
The Assistant Water Superintendent and Senior Treatment Plant Operators are responsible for reviewing and updating the ERP.  They must be revised in conjunction with local authorities whenever the facility hazardous materials operation changes, the Emergency Response Plan or Procedures fail in an emergency, the facility changes substanti 
ally in design, construction, or operation, the list of emergency coordinators or emergency equipment changes, or applicable regulations are revised.  If there are no emergency situations that require use of the ERP, it will be reviewed and updated annually.
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