Earl Schmidt Filtration Plant - Executive Summary
Facility Description: |
The Castaic Lake Water Agency (CLWA) Earl Schmidt Filtration Plant (ESFP) is located at 32700 North Lake Hughes Road near the community of Castaic in northern Los Angeles County, California. The plant is on a property covering approximately 1.3 million square feet. ESFP is provided State Project water stored in Castaic Lake. The plant is capable of treating 25 million gallons of water per day.
The treatment plant is conventional in design. The rapid mix chamber has the capacity for chemical additions of two coagulants, chlorine, powdered activated carbon, and pH-adjustment chemical. The flocculation chambers lead to sedimentation basins followed by filtration through to ten filters. In the final stage, filtered water is disinfected with chlorine, monitored for chlorine residual, and released for distribution.
Potentially hazardous chemicals that are stored and used onsite or for which storage is available include chlorine, propane, and sodium hydroxide. Liquid
chlorine, used for disinfection of water, is stored in 1-ton cylinders. The maximum quantity of chlorine stored at the plant is 16 cylinders (32,000 pounds). Chlorine is delivered in quantities above the RMP threshold. The other chemicals are either not covered under the RMP program, or are present in quantities below the thresholds.
Chemicals Subject To EPA's Accidental Release Prevention Program:
CLWA Earl Schmidt Filtration Plant uses chlorine stored in quantities large enough to trigger the Accidental Release Prevention Program. Chlorine used in disinfection operations is delivered to the plant by truck and stored onsite in one-ton cylinders.
Accidental Releases During Past Five Years:
The CLWA Earl Schmidt Filtration Plant has not had any releases during the past 5 years that resulted in any injuries, off-site evacuations, or property damage.
Process Safety Management Accident Prevention Program:
The CLWA Earl Schmidt Filtration Plant is subject to OSHA's Process Safety Man
agement (PSM) regulations for all equipment and operations associated with its chlorine system. The CLWA's PSM programs include the following activities to minimize the potential for an accidental release:
7 Review of the design of all equipment and controls for the chlorine system to ensure they are properly designed and installed.
7 Updating of standard operating procedures to include specific information on safety procedures. All procedures must be reviewed and certified annually.
7 Initial safety training and 3-year refresher training for all operators and maintenance staff.
7 Procedures to ensure that all contractors receive the same safety training that CLWA provides for its own employees.
7 Regular inspection of all equipment, monitoring systems and controls, with documentation of all inspections.
7 Prompt corrective action for any non-conforming items identified by the regular inspections.
7 Rigorous safety reviews conducted prior to system startup, if any equipment or o
perations are modified.
7 Investigation of any incidents that have the potential to have caused chlorine releases.
7 Periodic evaluation of the safety records of all outside contractors who work on the RMP-regulated systems.
7 Development of an effective emergency response program.
7 Implementation of an employee participation program to ensure that all plant-wide staff are aware of the PSM program, and are actively consulted regarding safety issues.
7 Independent audits of the entire PSM program and RMP program every three years.
Emergency Response Procedures:
CLWA Earl Schmidt Filtration Plant uses its Emergency Response Plan (ERP) to provide step-by-step procedures for emergency response in the unlikely event of an accidental release. The Plant Superintendent or Assistant Plant Superintendent maintains the ERP. The key elements of CLWA's emergency preparedness program are as follows:
7 The plant uses audible alarms to alert the staff of a potential accident.
7 In the event
of a large, release the facility would immediately contact the Los Angeles Fire Department.
CLWA Earl Schmidt Filtration Plant's Recent Steps to Improve Safety:
Based on recent safety reviews that were conducted as part of the evaluations for EPA's Accidental Release Prevention Program, CLWA Earl Schmidt Filtration Plant has implemented the following actions to either reduce the likelihood or severity of potential chemical releases:
7 Minimization of chlorine pressure piping to an inherently safer vacuum chlorination system.
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". The Toxic Endpoint Concentrations for various compounds were specified by EPA, and are generally concentrations that would cause no physical harm
but could interfere with people's ability to leave the area. The Toxic Endpoint Concentration for chlorine is 3 ppm.
In accordance with EPA's rule, two general types of hypothetical accidental release scenarios were developed:
7 The "Administrative Worst-Case Release" that arbitrarily assumes the entire contents of the largest container of chemical is released to the atmosphere in 10 minutes.
7 "Alternate Release Scenarios", which are releases that the safety review teams concluded have a realistic (but small) chance of actually occurring at the plant. These hypothetical releases generally consist of flange leaks, temporary process upsets, and breakage to pipes or tanks.
Worst-Case Release Scenario for Chlorine :
Anhydrous liquid chlorine (chlorine gas that is stored as a liquid under pressure at ambient temperature) is delivered to the site by truck and stored in a one-ton cylinder for use in the disinfection process. The Administrative Worst-Case Release Scenario assumes that
the entire ton of chlorine is emitted as a gas cloud in 10 minutes, during a period of exceptionally calm winds and stagnant atmospheric conditions (1.5 meters/second wind speed and F stability) that would result in minimal dispersion of the gas cloud. The thermodynamic properties of anhydrous chlorine indicate that such a large instantaneous gas release is nearly impossible. The release of a large quantity of gaseous or liquid chlorine from a cylinder would result in rapid chilling of the chlorine, and the formation of liquid or frozen chlorine. The liquid or frozen chlorine would take much longer than 10 minutes to vaporize into a gas cloud. Nevertheless, the RMP rule dictates that the Worst-Case Scenario assumes the release of one-ton of gaseous chlorine.
The formulas in EPA's RMP guidance for wastewater treatment plants were used to estimate the downwind impacts for the one-ton chlorine release. The formulas for chlorine apply to water treatment plants as well as wastewater trea
tment plants. Urban surface roughness conditions were used to account for buildings and trees in the vicinity of the facility. The model indicated that the gas chlorine cloud would travel 1.3 miles before it dispersed to the 3 ppm Toxic Endpoint Concentration.
The estimated residential population within a radius of 1.3 miles from the facility is 500 people.
Alternate Release Scenario for Chlorine :
The Process Hazard Analysis (PHA) team selected the following hypothetical accident as the Alternate Release Scenario: Chlorine is released through a break in a chlorine line. The release is stopped within 30 minutes.
Using EPA guidance, the calculated gaseous chlorine release rate is 12 lb/min. This rate takes into account the passive protection provided by the chlorine storage building. The calculated release rate is conservative because according to the Handbook of Chlorination, for a one-ton cylinder at 68 0F, a chlorine withdrawal rate in excess of 0.28 lb/min (400 lb/day) will lead
to a cooling of the system and potential freezing of the cylinder. Most of the released chlorine will freeze in a pool beneath the leak, and then be released at a much lower rate to the atmosphere. However, for the purpose of this evaluation, the calculated release rate of 12 lb/min was used.
The formulas in EPA's RMP guidance for wastewater treatment plants were used to estimate the downwind impacts for the chlorine release. The formulas for chlorine apply to water treatment plants as well as wastewater treatment plants. Urban surface roughness conditions were used to account for buildings and trees in the vicinity of the facility. The model indicated that the gas chlorine cloud would travel less than 0.1 miles before it dispersed to the 3 ppm Toxic Endpoint Concentration.
The estimated residential population within a radius of 0.1 miles from the facility is one person.