City of Marlin Water Treatment Plant - Executive Summary |
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Introduction The Marlin Water Treatment Plant (MWTP) produces approximately 1.7 million gallons of potable water each day for the City of Marlin. The plant uses approximately 160-240 pounds/day of chlorine gas to purify the water. The Environmental Protection Agency (EPA) lists chlorine as a toxic substance that is potentially harmful to humans and the environment. MWTP stores 8000 pounds of chlorine, liquefied under pressure, in (4) 1-Ton Cylinders. The EPA requires the plant to have a Risk Management Program (RMP) because there is more than 2500 pounds of chlorine in storage. The City of Marlin, like the EPA, are committed to chemical safety and thus created a RMP. This commitment starts with the Water Plant Supervisor and includes all of the Plant Operators. The purpose of the RMP is to prevent any accidental releases of chlorine gas and to mitigate the severity of releases that do occur. The Water Plant Supervisor for the City of Marlin Water Treatment Plant is responsibl e for the implementation and integration of the RMP. The RMP consists of the following: ?A worst case scenario giving the radius and population around the plant that could be exposed to high concentrations of chlorine gas. ?One alternative case scenario that is more realistic than the worst case scenario. ?Five-year accident history detailing MWTP's accidental releases of chlorine gas in the past five years. ?Management System for implementing and integrating the RMP. ?Prevention Program detailing safety information, the hazard review process, operating procedures, training, equipment maintenance, compliance audits, and incident investigations. ?Emergency Response Program detailing emergency response procedures and accident investigation and reporting. ?Planned Actions to Improve Safety at MWTP Worst Case Scenario The largest quantity of chlorine released is assumed to be 2000 pounds (a 1-Ton chlorine cylinder) in 10 minutes. The toxic zone around the plant is 1.3 miles with an estimated population of 50 (according to the Census Bureau). The toxic zone is the area around the plant with an airborne concentration of chlorine gas above 0.0087 mg/L (3 ppm), which is harmful to humans and environment. The model used to generate the toxic zone is from EPA regulations, 40 CFR (Code of Federal Regulations) 68.22 and program entitled "RMP Comp". The model parameters, stated in 40 CFR 68.22, are reasonable and consistent with MWTP. Alternative Case Scenario This scenario assumes that one of the valves is broken off the chlorine cylinder resulting in a 1" diameter hole. This scenario assumes 2000 pounds of liquid chlorine (a 1-Ton chlorine cylinder) are released at a rate of 2500 pounds/min. This rate is given in EPA's "Risk Management Program Guidance for Wastewater Treatment Plants 40 CFR Part 6 8" for a liquid chlorine release through a 1" diameter hole. The release occurs in less than a minute and results in a 0.7 mile toxic radius around the plant. The toxic zone has an estimated population of 20 (according to the U.S. Census Bureau). The model used to generate the toxic zone is from EPA regulations, 40 CFR (Code of Federal Regulations) 68.22 and program entitled "RMP Comp". The model parameters, stated in 40 CFR 68.22, are reasonable and consistent with MWTP. This model is reasonable to assume because one of the valves can be broken off, which would result in a 1" diameter hole in the cylinder. Five-Year Accident History MWTP has not had any "reportable" accidents in the past five years. A "reportable" accident is one that causes a death, injury, property damage, environmental damage, evacuations, or sheltering in place. Management System The City of Marlin already has a management system in place that ensures the implementation of this RMP. MWTP is a small facility and only one person, the Water Plant Supervisor, is responsible for the RMP. The Water Plant Supervisor is responsible to implement and integrate the RMP and ensure that it is communicated to everyone involved with MWTP operations. Prevention Program The MWTP prevention program is aimed to prevent accidental chlorine releases that could harm employees, the public, and the environment. This prevention program consists of the following sections: Safety Information-includes documentation of MSDS sheets, equipment specifications, codes and standards used to build, design, and operate the facility, safe upper and lower parameters in the chlorination system (such as temperature and pressure), and maximum intended inventory of chlorine. The safety information will be updated when there is a change in any of the above information. This information ensures that MWTP is aware of the safety-related aspects of the chlorination process. Hazard Review-includes a checklist and "What-If" questions. There are over 60 questions on the checklist and over 20 "What-If" questions. The hazard review will be conducted once every five years or when there is a major change in the chlorination process. These questions and checklist help identify hazards and safety deficiencies at the plant. Operating Procedures-includes step-by-step instructions for unloading chlorine cylinders, moving cylinders, hooking up regulators, starting up the chlorinators, checks during normal operations, starting up the stand-by chlorinator, shutting down the chlorinators, disconnecting the chlorine cylinders, a fire, and leaks. These procedures include performing equipment inspections, consequences for deviations from the procedures, and safety precautions. The operating procedures will be updated when there is a change in any of the procedures. Training-includes reviewi ng all the employees training records, determining who needs specific training, providing training for those without proper training, and providing refresher training. Training will be provided on an on-going basis with refresher training on the RMP at least once every three years. Maintenance-includes reviewing the maintenance requirements for the equipment, ensuring that all of the preventative maintenance is performed, and ensuring that only qualified contractors maintain the equipment. A qualified outside contractor will perform an annual inspection that includes testing of all the equipment in the chlorination process. Compliance Audits-includes performing an audit to evaluate the effectiveness of the prevention program. An audit of the prevention program will be performed at least once every three years. Incident Investigations-includes performing investigations for all incidents that could have resulted in a catastrophic release of chlorine. These incident investigatio ns will determine the cause of the accident, the contributing factors, and ways to improve the safety of the operation. Recommendations-includes those items that will improve the safety of the plant operations. These recommendations will result from reviewing all aspects of the prevention program. Corrective action will be recommended at any time a deficiency is noticed. Emergency Response Program MWTP emergency response program (ERP) is aimed to ensure the safety of the employees, the public, and the environment. The response program will be written into the community emergency response plan for Falls County. The ERP includes procedures for discovering a leak, determining the magnitude of the leak, containing both minor and major releases, fixing a minor leak, responding to a fire, and administering first aid. The ERP also includes site security and control, drills and exercises for a release, training for a release, maintenance and testing of emergency response equipmen t, reviewing and updating the ERP, coordination with other organizations (fire department, hospital, and police department), public awareness, and investigation of an accident. The investigation will determine the primary and secondary causes and necessary actions to prevent other accidents. The Water Plant Supervisor is responsible to ensure that all other parties can provide effective and adequate response to an emergency chlorine release at the plant. Planned Changes to Improve Safety at MWTP MWTP has developed a list of changes that need to be made to further minimize the chances of an accidental chlorine release. MWTP is in the process of making the following changes: ?Post hazardous warning signs in appropriate places. ?Clearly label all components in the chlorination system. ?Install new hoist ?Inform residences around the plant about the chlorine and what to do in the event of an emergency ?Train operators in operating and emergency response procedures. ?Post emergency response procedures in appropriate locations. ?Ensure that the ERP is included in the community emergency response plan. ?Post emergency exit signs in the appropriate locations. The operators of MWTP will continue to improve the Risk Management Program as well as all the safety-related aspects of the chlorination system at the plant. |