Franklin Area Wastewater Treatment Plant - Executive Summary |
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1. PURPOSE Franklin Area Wastewater Treatment Plant (FAWWTP) processes 3.2 million GPD of water from the Communities of Carlisle, Germantown, Franklin, and unincorporated areas of Montgomery and Warren Counties. The FAWWTP is a secondary treatment facility. The chief objective of secondary treatment is to reduce the concentration of dissolved and colloidal organic matter contained in the wastewater that cannot be removed by primary treatment. Chlorine is added to the secondary clarifier effluent between May 1 and October 31 each year. Sulfur dioxide is then added to remove residual chlorine before final discharge to the Great Miami River. 2. STORAGE Chlorine is delivered to the treatment plant in one-ton containers. By administrative control, a maximum of 3 one-ton containers of liquid chlorine is stored on site in the chlorine storage room. 3. ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES AT THE FACILITY The Franklin Area Wastewater Treatment Plant Risk Manageme nt Program (RMP) includes the following key elements to mitigate the effects of potential chlorine release hazards. 7 Operator training 7 Preventive maintenance program 7 Process specific safety equipment 7 Safe and effective standard operating procedures, written with operator participation 7 Hazard review of equipment and procedures 7 Auditing and inspection programs 7 Comprehensive management program Further, FAWWTP maintains an active environmental, health and safety program with the following elements specifically supporting the safe handling of chlorine and the chlorination process. 7 Respiratory protection (SCBA) program 7 Chlorine detectors 7 Chemical right to know program 7 Personal protective equipment program 4. DESCRIPTION OF THE FACILITY AND THE REGULATED SUBSTANCES HANDLED Lift station area equipped with manually cleaned bar screens to remove large objects. Two primary clarifiers collect and remove material which will readily float or settle. Activated sludge process i s a method of biological secondary treatment. The primary clarifier is a nine million-gallon lagoon equipped with 2,500 fine-bubble diffusers. Chlorine is delivered to the treatment plant in one-ton containers. A maximum of 3 one-ton containers of liquid chlorine is stored on site in the chlorine storage room. Chlorine is added to the secondary clarifier effluent between May 1 and October 31 each year. Sulfur dioxide is then added to remove residual chlorine before final discharge to the Great Miami River. 5. WORST-CASE RELEASE SCENARIO The worst-case release scenario as postulated in the regulation (40 CFR 68.25) is the release of the greatest quantity (of chlorine) in a single vessel. The entire contents of this vessel are assumed to be released as a gas over a 10-minute period. The largest single vessel at the treatment plant is a one-ton container; therefore, 2,000 pounds of liquid chlorine will be released as a gas over a 10-minute period. A release of this magnitude would on ly be possible if the shell of the container failed and the liquid chlorine formed a pool and vaporized over a 10-minute period. The likelihood of this type of catastrophic release is very minimal. According to EPA's model RMP*Comp (TM), using the rural site option, the distance to the endpoint is 3.0 miles. There are 17 schools, one hospital, 6,218 residences, and a population of 17,350 within a 3-mile radius of the facility. The meteorological conditions associated with the worst-case release scenario, as prescribed in the regulation, is a wind speed of 1.5 meters per second (3.36 miles per hour) and very stable atmospheric conditions. These stable atmospheric conditions will limit the mixing of the chlorine gas with the ambient air as the gas travels downwind from the point of release. The cloud formed by the chlorine release will grow in size and decrease in concentration as it travels downwind. 6. ALTERNATIVE-CASE RELEASE SCENARIO The alternate release scenario is one that is more likely to occur than the worst case release scenario. For this scenario, it was assumed that the pigtail is sheared off and mitigation occurs in one hour. The pigtail connects the 1-ton container to the manifold. This assumption is based on the alternate release scenarios listed in Edition 3 of The Chlorine Institute Pamphlet No. 74 - Estimating the Area Affected by a Chlorine Release, Section 4.5.6, April 1998. The tested evaporation rate of the contents of the 1-ton container is 21 pounds per minute. This release rate is assumed to continue over a one-hour period for a total release of 1260 pounds of chlorine. For this scenario, the meteorological conditions prescribed in the regulation are neutral atmospheric stability conditions and a wind speed of 3 meters per second (6.7 miles per hour). According to EPA's model RMP*Comp (TM), using rural site, the distance to the endpoint is 0.2 miles. There are no schools, no hospitals, 61 residences, and a population of 167 within a 0 .2-mile radius of the facility. Census data and the location of schools, hospitals, etc. were obtained from the LandView III mapping system that includes database extracts from U. S. EPA, the Bureau of Census, the U. S. Geological Survey, the Nuclear Regulatory Commission, the Department of Transportation, and the Federal Emergency Management Agency. 7. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL-SPECIFIC PREVENTION STEPS The facility complies with EPA's accident prevention rule and all applicable state and local codes and regulations. The chlorine system is designed, installed, and maintained in accordance with applicable codes and state law. The treatment plant maintains a Self-contained Breathing Apparatus (SCBA) and The Chlorine Institute's Emergency Kit "B" for one-ton containers. This equipment is stored in a room that is adjacent to the room that houses the ton containers. FAWWTP personnel receive training on the use of the breathing apparatus and the emerge ncy kit. The kit contains the necessary tools and other equipment to contain valve leaks and repair small holes in a ton container, and capping devices for the fusible plugs in the ton containers. Ton containers are equipped with fusible metal pressure relief devices. Most ton containers have six fusible metal plugs, three in each end. The fusible metal is designed to melt between 158 degrees F and 165 degrees F to relieve pressure and prevent rupture of the container in case of fire or other exposure to high temperature. Chlorine gas is heavier than air and will settle to the lowest elevation when released. The chlorine storage area is equipped with an exhaust fan that is mounted near the floor on an outside wall. There are also air intake vents located near the floor so that the chlorine gas will be vented outside the building. The fan can be activated by a switch located outside the building and also by a switch inside the building. Two exit doors are provided in the chlo rine storage room. 8. FIVE-YEAR ACCIDENT HISTORY FAWWTP has never had an accident involving chlorine that required hospitalization, care by a physician or that caused death, injury, property/environmental damage, evacuations, or shelterings-in-place. 9. EMERGENCY RESPONSE PROGRAM The FAWWTP has a site specific Emergency Response Plan (ERP), revised April 5, 1999, that outlines employee procedures in the event of an emergency. The facility's ERP includes specific procedures for material handling, emergency planning, evacuation, contact for emergency response organizations, reporting, training, fire protection, and media relations. The facility is presently working with an agreement between the FAWWTP and the local fire department for chemical spills, fires, and chlorine emergencies. 10. PLANNED CHANGES TO IMPROVE SAFETY- None |