City of Marion,OH. Div. of Water Pollution Control - Executive Summary |
|
Executive Summary: The City of Marion, Ohio - Division of Water Pollution Control services a population of approximately 40,000 people. The wastewater treatment plant processes an average of 8.5 million gallons per day of wastewater in this central Ohio town, located approximately 45 miles north of Columbus, Ohio. Our primary method of disinfection is accomplished via Chlorine. The treatment plant utilizes 2000 pound steel cylinders. We have no more than 12,000 pounds of chlorine on site during the May to November season. The cylinders are carefully off-loaded from semi-trucks via overhead rail system and secured upon floor mounted saddles under roof and isolated from plant traffic patterns within a secured room. Based upon demand, the cylinders are then hoisted from the saddles and transferred to the chlorine dosage room where they are placed into service by connecting the cylinders to the vacuum regulators. The chlorine gas is fed to the vacuum regulator where it is heated prior to the piping going to the injectors, mixed with water and delivered as a chlorine - water solution. The integrity of all fittings are tested routinely using ammonia in a squeeze bottle. The ammonia vapor released around the fittings exposes any chlorine leaks by forming a white cloud. The secured room in which the chlorine cylinders are stored is well maintained with an early detection system and ventilation designed for a release event. To date, no major release has occurred. Process Hazard Analysis-worst case scenario (RMP*Comp. Version 1.06): Chemical: Chlorine CAS#: 7782-50-5 Category: Toxic gas Scenario: Worst Case Quantity Released: 2000 pounds Release Duration: 10 minutes Release Rate: 110 lbs/min Mitigation measures: Released within an enclosed room Topography: Urban surroundings with many obstacles in the immediate area Toxic Endpoint: .0087 mg/L; basis: ERPG-2 * Estimated distance to the toxic endpoint is 0.9 miles or 1.4 Kilometers Wind Speed: 3.4 miles per hour Stability Class: F Air Temperature: 77 degrees F (25 degrees C) |