Garrett A. Morgan Water Treatment Plant - Executive Summary |
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The Facility & the Regulated Substances Handled The Cleveland Division of Water (CWD) is a municipal water utility that provides 1.5 million people throughout the greater Cleveland area with high-quality, safe drinking water. One of four CWD water treatment plants, the Garrett A. Morgan Water Treatment Plant produces approximately 29 billion gallons of drinking water each year. Chlorine is used at the plant as the primary disinfectant. Chlorine has been used to disinfect drinking water for nearly 100 years, reducing or eliminating the risk of such waterborne diseases as cholera, typhoid, and dysentery. Approximately 2,000 pounds of chlorine is used each day at the plant as a part of the treatment process. Chlorine is supplied to the water plant as a liquid under pressure in one-ton steel containers. The facility can store a maximum of 32 one-ton containers (i.e., 64,000 pounds) on-site at any one time. Summary of Major Hazards Chlorine is considered a highly hazardous chemical b y both the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA) as exposure to chlorine can result in serious health effects. The primary health concern from exposure to chlorine is its toxic effect when inhaled. At the Garrett A. Morgan facility, the chlorination system is a closed system that converts liquid chlorine to chlorine gas and then injects the gas into water to form chlorine solution. The chlorine solution can be added into the water in the water treatment process at three locations throughout the plant. Consequences of Failure to Control the Hazard EPA regulations require CWD to analyze a worst-case and an alternative release scenario to determine the potential off-site impact zone resulting from a failure to control the chlorination system. According to EPA definitions, the worst-case release scenario at Garrett A. Morgan is the complete failure of a one-ton container of chlorine which results in a release of 2,000 pounds of liquid chlorine (with subsequent vaporization) over a 10-minute period. The worst-case release scenario does not take into consideration active mitigation measures such as equipment, devices or technologies which require human, mechanical, or other energy input to function. Therefore, assuming the worst weather conditions, the resulting chlorine vapor could potentially travel 0.9 miles before dispersing enough to no longer pose a hazard to the public. CWD used EPA's off-site consequence analysis modeling program RMP*Comp to calculate the estimated distance to the chlorine toxic endpoint. The potential occurrence of the worst case scenario is mitigated by both passive and active devices and procedures in place at the Garrett A. Morgan facility. CWD controls the likelihood of the worst case scenario happening by implementing Standard Operating Procedures (SOPs) for safely connecting and disconnecting one-ton containers and, by the use of Chlorine Institute Emergency B Kits to m inimize releases. A more realistic release scenario for the Garrett A. Morgan Water Treatment Plant is the alternative release scenario which is defined as a tubing failure, bad connection or a valve failure on a one-ton container of chlorine. In this scenario, CWD analyzed the results of a liquid and gaseous chlorine release through a 5/16-inch-diameter valve body opening on the container at a release rate of 241 pounds per minute for 10 minutes. According to EPA's RMP*Comp the estimated distance to the chlorine toxic endpoint is 0.2 miles. The alternative release scenario incorporates both passive and active mitigation measures to minimize the off-site effects of a release. For example, all of the one-ton containers are stored in an enclosed building to minimize releases to the environment and migration off site. We also employ the use of Chlorine Institute Emergency B Kits should a release occur further mitigating the possibility of a release migrating off site. Emergency Re sponse Program This facility has a chlorine-specific Emergency Response Plan which identifies procedures for recognizing emergencies, securing incident areas, and responding to releases and leaks; emergency evacuation procedures, routes, and safe assembly points; procedures for accounting for all personnel following an evacuation; emergency first aid procedures for exposure to chlorine, procedures for notifying local emergency response agencies and the public; and a list of facility personnel currently assigned as members of the emergency response team and their responsibilities. All of the water treatment plant operators are properly trained to respond to and mitigate chlorine incidents that might potentially occur at the plant. The operators are also trained in the use of Chlorine Institute Emergency B-Kits for one-ton containers. Garrett A. Morgan is staffed with operators 24 hours a day. In addition, CWD is coordinating it's Emergency Response Plan with the Cleveland Hazardous M aterials (HAZMAT) Team and the Cuyahoga County Local Emergency Planning Commission (LEPC). In conjunction with the establishment of an RMP Program, CWD established a program to conduct annual chlorine drills with Cleveland HAZMAT for preparation for response to an accidental release. Accidental Release Prevention Program CWD has long understood the hazards of handling chlorine which, if not handled properly, can pose a risk to employees, the environment, and the surrounding community. With the inception of OSHA Process Safety requirements, CWD has worked hard at building what we call a "Layers of Protection" approach to safety. CWD has developed and implemented detailed Standard Operating Procedures (SOPs) for the safe operation of the Chlorination System, a comprehensive maintenance program for inspecting, testing, repairing, and replacing chlorine equipment including detection systems, alarms, and emergency equipment; personnel protection equipment (PPE) policies; employee trainin g; incident reporting and investigation procedures; safe work practices such as hot work permits and lockout/tagout procedures; and a Visitor Policy to control access to the plant especially to areas where chlorine is stored and/or used. These programs are in place to reduce the likelihood of an accidental chlorine release. In addition to CWD's well-maintained chlorine equipment and well-trained employees, CWD's management is committed to minimizing the potential for accidental chlorine releases and minimizing the effects of a release if one were to occur. CWD routinely re-evaluates and updates it's policies, programs, and procedures to ensure that we are providing the safest environment possible for our employees, the community, and the environment. Five-year Accident History The Garrett A. Morgan Water Treatment Plant has used chlorine to disinfect drinking water for more than 80 years. In the last five years, the facility has had only one incident which was considered serious enough to report under the RMP. An electrician was performing maintenance work on a low pressure alarm switch on a manifold. The individual was exposed to residual chlorine that was trapped in the switch. Unfortunately, this employee was not wearing the proper PPE for performing work on the chlorine system. The employee was sent to the hospital for respiratory irritation, was treated and released. Proper PPE and maintenance procedures were reemphasized after this incident. Planned Changes to Improve Safety CWD is always researching ways to improve safety and reduce risk. During a recent chlorine Process Hazard Analysis (PHA) at the Garrett A. Morgan Water Treatment Plant, several recommendations were made to improve safety at the plant. The recommendations ranged from adding procedures to the SOPs, installing additional motorized valves on chlorine gas vacuum lines to minimize releases due to a break in a process line, interconnecting the chlorine leak notification alarms thro ughout the plant, purchasing hand-held chlorine meters for use in inspecting containers prior to acceptance, tagging valves to coincide with SOPs, to investigating the use and operability of motorized emergency shut-off valves for the one-ton containers. Furthermore, over the next several years the Morgan Water Treatment Plant is scheduled to undergo major renovations as part of CWD's Plant Enhancement Program, including the conversion from chlorine to sodium hypochlorite for disinfection of drinking water. |