Robert A. Perdue Water Treatment Plant - Executive Summary
ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES |
The Sweetwater Authority facility abides by the emergency response procedures and policies detailed in the Emergency Response Plan manual. This Plan was designed to meet the following objectives:
1.) To save lives.
2.) To minimize and avoid injuries.
3.) To protect the environment.
4.) To minimize property damage.
Sweetwater Authority maintains a Hazardous Response Team whose members are the designated emergency coordinators for the facility. The Plan provides the response organization and notification procedures, evacuation routes, chlorine health hazards, and mitigation procedures which will be implemented to respond effectively to emergency situations that may arise at the facility. This Plan is reviewed and updated at least once per year. This Plan was reviewed and updated to ensure compliance with the PSM and RMP regulations, as well as to incorporate any facility changes.
STATIONARY SOURCE AND REGULATED SUBST
The Sweetwater Authority facility uses a chlorine system to treat water. Chlorine is used as a disinfectant to purify the water. The chlorine is delivered to the facility in one ton containers. The liquid chlorine leaves the one ton containers and enters the evaporators. These evaporators turn the liquid chlorine into a gas. The chlorine gas then proceeds to the chlorinators. From the chlorinators the chlorine is pulled into the injectors, which then send the chlorine into the water treatment process.
In the chlorine tank room at Sweetwater Authority there are two chlorine tanks connected to the chlorine system. Only one is used at a time. The controller in the chlorine tank room monitors the weight of each one ton chlorine container. When the tank in operation is close to empty, the controller shuts off the valve connected to that tank and opens the valve connected to the full tank. The empty tank is then replaced with a full tank from the storage area. This replacem
ent is done by the Sweetwater Authority operators wearing appropriate personal protective equipment and using the monorail hoist system.
The maximum total chlorine inventory is 36,000 pounds.
HAZARD ASSESSMENT SUMMARY
* Worst Case Release Result Summary
Scenario Description: Release of the two one ton containers (4,000 pounds) of chlorine in 10 minutes. The release is enclosed by the building which provides passive mitigation of the release. The most pessimistic meteorological conditions were used: 1.5 m/s and F stability. The EPA's RMP Guidance for Wastewater Plants was used as the reference for determining the off-site toxic endpoint. This potential release reaches off site of the facility boundaries and may impact population receptors.
* Alternative Release Result Summary
Scenario Description: A 0.25 inch diameter leak of high pressure liquid chlorine for one hour. The quantity of ammonia released in one hour at this rate is the entire contents of both one ton contain
ers (4,000 pounds). The meteorological conditions used were 3 m/s and D stability. The EPA's RMP Guidance for Wastewater Plants was used as the reference for determining the off-site toxic endpoint. This potential release reaches off site of the facility boundaries and may impact population receptors.
ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL-SPECIFIC PREVENTION STEPS
Sweetwater Authority has a Process Safety Management program in place to manage the handling of chlorine. In addition, common industry standards, policies, and procedures are utilized to ensure safe practices are being performed. This includes common practices outlined by the Chlorine Institute. Chlorine gas detectors are located in the chlorine tank storage room, the chlorinator room, and the evaporator room. There are fire detectors throughout the facility as well.
FIVE YEAR ACCIDENT HISTORY
The accident history researched back five years (since June 1994) shows that the Sweetwater facility has not h
ad an accidental release or "near miss" of chlorine. In addition, there have been no injuries resulting from a chlorine release.
EMERGENCY RESPONSE PROGRAM
Sweetwater Authority has a Hazardous Response Team that is trained to respond to chlorine emergencies. The operators and maintenance technicians are trained in the use of self-contained breathing apparatus (SCBA) and chlorine repair kits (Type B Kit). Annual refresher courses are held for the Sweetwater Authority operators, maintenance staff, and laboratory staff which deal with the procedures for handling hazardous materials. The local police, fire, and hazardous materials agencies have been integrated into the facility response plan.
For a small leak, Sweetwater Authority personnel would use their SCBA to enter the Chlorination building and shut off the tank supply valves. For a major leak, the Authority would notify the Fire Department and then (wearing their Class A suit and SCBA) isolate the leak. If the Type B Kit i
s required, Sweetwater Authority personnel are trained and would use the Kit to stop the leak.
PLANNED CHANGES TO IMPROVE SAFETY
The Process Hazard Analysis (PHA) Revalidation provided the mitigation measures outlined below to improve safety at the Sweetwater Authority Water Treatment Plant. The PHA Revalidation was comprised of one session that included a HAZOP study, a Plant Walkthrough, a "What-if" analysis, and a series of checklists. The following recommendations will be in place by June 21, 2000.
* Recommendations from Initial PHA:
Check the feasibility of being able to close the switchover valves (MV-503 and MV-507) from outside of the chlorine room to minimize a release.
Implement formal inspection program for the pressure switches. Document test.
Consider adding a LED for each expansion chamber pressure switch. The LED could light when the pressure alarm went off. This would allow the operators to distinguish which pressure alarm went off.
* PHA Revalidation Sessio
REV01 Include appropriate hospital/first aid for injuries from chlorine exposure in the Emergency Response section. Provide reference to the Process Safety Information section for first aid information.
REV02: Formalize the Operating Procedures annual review. Include the Annual Certification form in the Operating Procedures section of the PSM program.
REV03: Include the Faulty Equipment form in the Mechanical Integrity section of the PSM program.
REV04: Ensure that operators/maintenance personnel are documenting the date of required maintenance.
REV05: Update Section F, Respirator Protection Program, of the Safe Work Practices section of the PSM program document to reflect the updated Sweetwater Authority program.
REV06: Use the Management of Change record form for the installation of the new chlorine sensors.
REV07: Conduct a Process Safety Management audit at least every three years as required by Cal-OSHA '5189(o).