Bailey Water Conditioning Facility - Executive Summary
SECTION 112(r) RISK MANAGEMENT PLAN |
FACILITY: CITY OF BUENAVENTURAS BAILEY WATER CONDITIONING FACILITY
The City of San Buenaventura (City) constructed the Bailey Water Conditioning Facility (Bailey WCF) in the late
1970s to treat groundwater for iron and manganese. The facility was expanded in 1998 to treat 11.5 million gallons
per day of groundwater to help meet the Citys domestic water service demands. A gaseous chlorine system is used
at the Bailey WCF to oxidize the iron and manganese in the influent well water and to provide a chlorine residual in
the water for disinfection. The facility is equipped with chlorine detectors and a chlorine vapor scrubber system.
The facility is normally un-manned. Operators and maintenance staff travel to the Bailey WCF from the Citys
operation center at the Avenue Water Treatment Plant in Ventura.
CHEMICALS SUBJECT TO ARPP RULE
The Bailey facility uses chlorine in quantities large e
nough to trigger the Environmental Protection Agencys
Accidental Release Prevention Program (EPAs ARPP) and Californias Accidental Release Prevention Program
(Cal ARPP). One-ton cylinders of liquid chlorine are delivered to the plant by truck. A maximum of 9 one-ton
chlorine cylinders can be stored onsite in a building equipped with gas detectors and an automatic emergency
ACCIDENTAL RELEASES DURING PAST 5 YEARS
The facility has not had any releases during the past 5 years that resulted in any injuries, off-site evacuations, or
PROCESS SAFETY MANAGEMENT ACCIDENT PREVENTION PROGRAM
The facility is subject to OSHAs Process Safety Management (PSM) rule. The City has developed a stringent PSM
safety program that includes the following elements:
? Review of the design of all equipment and controls for the chlorine system to ensure they are properly designed
? Updating of standard operating procedures to include specific infor
mation on safety procedures. All procedures
must be reviewed and certified annually.
? Initial safety training and 3-year refresher training for all operators and maintenance staff.
? Procedures to ensure that all contractors receive the same safety training that the City provides for its own
? Regular inspection of all equipment, monitoring systems and controls, with stringent documentation of all
? Prompt corrective action for any non-conforming items identified by the regular inspections.
? Rigorous safety reviews conducted prior to system startup, if any equipment or operations are modified.
? Stringent investigation of any incidents that have the potential to have caused chlorine releases.
? Periodic evaluation of the safety records of all outside contractors who work on the RMP-regulated systems.
? A site-specific Emergency Action Plan.
? Implementation of an employee participation program to ensure that all plant staff are aware of t
program, and are actively consulted regarding safety issues.
? Independent audits of the entire PSM program and RMP program every three years.
EMERGENCY RESPONSE PROCEDURES
City staff uses its Emergency Action Plan to provide step-by-step procedures for emergency response in the unlikely
event of an accidental release. The key elements of the emergency preparedness program are as follows:
? All plant staff (including administrative and clerical staff) are trained in the specific elements of the program.
? The chlorine building is equipped with electronic chlorine detectors and an automatic emergency scrubber
system large enough to handle the entire contents of a 1-ton chlorine cylinder. The chlorine detector has an
audible alarm and alerts the Citys central operations control room.
? In the event of a large release, the facility would immediately contact the City of San Buenaventura Fire
? A team of City supervisors and operators are fully
trained, certified and equipped for hazardous materials
(HazMat) emergency operations to repair accidental releases. The Ventura Fire Department and the City
HazMat team would jointly repair any major leaks.
CITYS RECENT STEPS TO IMPROVE SAFETY
Based on recent safety reviews that were conducted as part of the evaluations for EPAs Accidental Release
Prevention Program, the City has implemented the following actions to either reduce the likelihood or severity of
potential chemical releases:
? Update written operating procedures to include all PSM-required information.
? Improve cabinets for storage and labeling of emergency repair kits.
? Provide wheel chocks for the delivery trucks to assist with the unloading/loading of cylinders.
? Improve labeling on process piping.
? Upgrade the emergency repair kit by purchasing rubber sheets that can strapped around a damaged 1-ton
cylinder to reduce leakage. This repair method will be useful in reducing the impacts of
an accident similar to
the Alternate Release Scenario described below.
HYPOTHETICAL ACCIDENTAL RELEASE SCENARIOS
The Risk Management Plan must assess the downwind impacts of hypothetical accidental releases. EPA requires
facilities to model the distance that a plume of released gas would travel before it dispersed to an ambient
concentration equal to the Toxic Endpoint Concentration. Toxic Endpoint Concentrations for various compounds
were specified by EPA, and are generally concentrations that would cause no physical harm but could interfere with
peoples ability to leave the area. The Toxic Endpoint Concentration for chlorine is 3 parts per million (ppm). In
accordance with EPAs rule, the following hypothetical accidental release scenarios were developed:
Worst-Case Release Scenario for Chlorine
Liquid chlorine (chlorine gas that is stored as a liquid under pressure at ambient temperature) is imported to the site
by truck and stored in one-ton containers for use
in the oxidation/disinfection process. The Administrative Worst-
Case Release Scenario assumes that the entire contents of one of the chlorine cylinders (2000 pounds of chlorine) is
emitted as a gas cloud in 10 minutes, during a period of exceptionally calm winds and stagnant atmospheric
conditions (1.5 meter/second wind speed and F stability) which would result in minimal dispersion of the gas
cloud as it blew downwind. The thermodynamic properties of chlorine indicate that such a large instantaneous gas
release is probably impossible. If the entire 2000 lbs of liquid chlorine were somehow discharged from the cylinder,
it would spill on to the ground and immediately cool itself until it formed a puddle of chlorine ice, which would
take much longer than 10 minutes to evaporate into a gas cloud. Nevertheless, the RMP rule dictates that the
Worst-Case Scenario assumes the release of 2000 lbs of gaseous chlorine.
Graphs from EPAs RMP Guidance for Wastewater Treatment P
lants were used to calculate the downwind
impacts. EPAs graphs indicate that the chlorine gas cloud would travel 1.3 miles before it dispersed to the 3 ppm
Toxic Endpoint Concentration. Figure 1 shows a circle defined by the worst-case 1.3 mile downwind distance.
Alternate Release Scenario for Chlorine
The Alternate Release Scenario for chlorine assumes that one of the 1-ton cylinders is dropped from the delivery
truck on to the ground outside the chemical building. To be conservative it was assumed that the dropped cylinder
lands on its weakest point, splitting a seam to cause an 8 x < crack. It was also assumed that the dropped cylinder
comes to rest with the crack below the liquid level in the cylinder, allowing half of the liquid contents to
immediately drain on to the ground. The thermodynamic properties of chlorine dictate that 12% of the spilled
chlorine would immediately flash to a vapor that would form a dense cloud that could blow downwind. The
odynamic properties also dictate that the spilled liquid would immediately chill to chlorines boiling point (-
29 degrees F), forming a puddle of chlorine ice. To be conservative it was assumed that 60% of the spilled
chlorine ice would evaporate in the first 30 minutes. The rate of evaporation would decrease as the chlorine ice
puddle shrank. Of the 1,000 pounds of liquid spilled from the dropped cylinder, 649 pounds would be emitted as a
gas during the first 30 minutes.
Graphs from EPAs RMP Guidance for Wastewater Treatment Plants were used to calculate the downwind
impacts. EPAs graphs indicate that the chlorine gas cloud would travel only 0.1 mile before it dispersed to the 3
ppm Toxic Endpoint Concentration. Figure 1 shows a circle defined by the worst-case 0.1 mile downwind distance.
The dispersing chlorine gas cloud would extend into the residential area surrounding the facility.