Bailey Water Conditioning Facility - Executive Summary

| Accident History | Chemicals | Emergency Response | Registration | Source | Executive Summary |

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. 
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  
The facility has not had any releases during the past 5 years that resulted in any injuries, off-site evacuations, or  
property damage. 
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  
and installed. 
? 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 
he PSM  
program, and are actively consulted regarding safety issues. 
? Independent audits of the entire PSM program and RMP program every three years. 
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. 
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. 
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. 
Filename:  execbail.doc
Click to return to beginning