Paris Wastewater Treatment Plant - Executive Summary |
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Paris Wastewater Treatment Plant, located at 6500 Bypass, Paris, KY, has one independent chlorine and sulfur dioxide injection system. The chlorine and sulfur dioxide storage and feed systems are located outdoors. The chlorination and sulfur dioxide injector process is located inside a building. Both the chlorine and sulfur dioxide systems have one (1) one-ton container on line and one (1) one-ton container on standby at any one time. Usually, there are containers containing chlorine or sulfur dioxide in storage. The system is operated under vacuum using gases. There is a Vacuum Regulator-Check Unit (Wallace & Tiernan 500 lb/24 hour capacity) which automatically shuts off the cylinder in the event of a break in the vacuum line. The chlorine supply system automatically switches between the on-line and standby chlorine containers when the on-line container is depleted. A similar system is used to supply sulfur dioxide (Wallace & Tiernan 475 lb/24 hour capacity). The facility ha s chlorine and sulfur dioxide detectors to monitor leakage in the chlorinator/sulfonator room. The sensors are located at about twelve inches above floor level. The detectors will automatically alarm at the Facility and at the main control room panel. All gas cylinders (empty and full) are stored on the loading dock. The facility normally has a maximum of 4,000 plus pounds of chlorine and sulfur dioxide at the site at any one time. Delivieries are arranged to take place when all cylinders are near empty. During chlorine/sulfur dioxide deliveries, the delivery truck backs up to the unloading area and the cylinders are taken off the truck via the facility's crane and placed onto the dock. Normally, the chlorinator/sulfur dioxide injector room is secured with doors that remain closed except when the system is being inspected. Inspection takes place daily. If a chlorine/sulfur dioxide leak is detected, the respective alarm will sound and the Operator will notify the Plant Superv isor. The Operator and Standby will don the Self-Contained Breathing Apparatus (SCBA) and the operator will then investigate the cause for the alarm. Exhaust fans will be activated from the exterior of the building. The air inside the building is evacuated and fresh air is drawn into the building through upper and lower vents respectively. The Standby will remain outdoors in contact with the Operator ready to call for outside assistance if needed. The Operator and the Standby are trained in chlorine safety and emergency procedures. The Operator will shut the chlorine cylinder. If the leakage is not stopped the Fire Department will be contacted and the exhaust fans shut down to try to contain the leak within the building. The Worst Case release for this facility assumes that a one-ton sulfur dioxide cylinder ruptures during unloading outdoors in a rural area. The cylinder discharges a dense gas release under worst case meteorological conditions of F Stability and 1.5 meters pe r second and ambient temperature of 250C. All two thousand pounds contained in the cylinder are assumed released over ten (10) minutes. It is only presented for comparative purposes and for non-OSHA facilities to determine under which RMP Program Level the facility fits. The Worst Case Impact Area is three and one-tenth (3.1) miles in radius (EPA CEPP Risk Management Program Guidance For Wastewater Treatment Plants EPA 550-B-98-010 October 1998). There are about 2,300 people living in the Worst Case release area who could be affected by this type of release. Located within this area are three schools (Western High School, Paris High School, and South Side School). There are no churches, hospitals, child day care facilities, or nursing homes in the area. The Most Likely case release assumes a release of chlorine or sulfur dioxide occurs due to a pipe leak in the storage or chlorinator/ sulfur dioxide injector area. In order to have a leak that emits chlorine or sulfur dioxide ou tside of the facility, it is necessary to assume the alarm is activated and the automatic cylinder vacuum loss shut off fails. The alarm would sound and the facility's emergency response team would be at the location within a few minutes to shut the system down at the cylinder. Under those assumptions, the most likely release case is assumed to be a steady-state leak of up to 5 pounds per minute of chlorine (either as a gaseous or a two-phase release) for 30 minutes (150 lbs). It should be noted that a completely filled one-ton cylinder has maximum gaseous discharge rate of about 500 pounds per day (0.35 pounds per minute). Significant gaseous discharges above this rate will result in the cylinder freezing up and the discharge stopped. The Facility has only one (1) one-ton cylinder hooked up to the header and a maximum discharge rate from that system could be 0.35 pounds of chlorine per minute. It is also assumed that the cylinder discharges a dense gas release under meteorologic al conditions of D Stability and 3.0 meters per second at an ambient temperature of 250 C. A similiar situation was evaluated for sulfur dioxide assuming a 30 minute release of 150 pounds (actual maximum dischare rate of 475 pounds per day or 0.33 pounds per minute). The Most Likely Case Impact Area based upon the above conditions for chlorine and sulfur dioxide is a tenth (0.1) of a mile in radius (EPA CEPP Risk Management Program Guidance For Wastewater Treatment Plants EPA 550-B-98-010 October 1998). It is estimated that there are 10 people living in the Most Likely Case release area who could be affected by this release. There are no schools or hospitals located within this area. Adjacent to the site is a soccer field which is partially within the 0.1 mile area. However, most of this release would be contained on the Facility's property. The Facility has not had an accidental release of chlorine or sulfur dioxide from this facility in the five years prior to the submission of this Risk Management Plan (RMP). |