Wastewater Trearment Facility - Executive Summary |
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NAVASOTA, TEXAS TOXIC GAS RISK MANAGEMENT PLAN EXECUTIVE SUMMARY OVERVIEW: The City of Navasota, Texas has two facilities that uses chlorine gas in amounts that require a Risk Management Plan in order to be in compliance with the Clean Air Act. One of these is the city wastewater treatment plant and the other is the domestic water facility. These two facilities are located approximately a mile apart, and are treated as two separate processes. The process for handling the chlorine containers is the same at each location. At each location, chlorine gas from one ton containers is added to the water/wastewater system. There are two one ton cylinders at each site. Chlorine is dispensed from only one cylinder at a time. The supply is automatically switched when a cylinder becomes empty. When a cylinder is emptied, a full, replacement container is ordered. This is offloaded from the vendors delivery truck with a hoist operating from a monorail. The cylinder is placed on a scale support where it remains until it is empty and is loaded onto the vendors delivery truck. Once the cylinder is set on the scale it is not moved until it is empty. All connections to the cylinder are made after it is on the scale. There are two full time employees that are responsible for the two sites. ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE: Due to minimum handling of the cylinders and protective guards around the valves, the possibility of accidental release is extremely remote. Accidental release prevention is accomplished by careful attention to unloading cylinders, installing regulators and connecting to the injection system. The emergency response will be to repair any source of release, alert local emergency response teams, and evacuate adjacent local receptors as required. RELEASE SCENARIOS: The worst case release scenario is the mandatory 10 minute release of the entire contents of the cylinder. The alternative release scenario is damage to the connections on the cylinder. Due to the short time involved in the release of both scenarios, there are no administrative controls or mitigation measures planed to limit the end point distances. PLANNED CHANGES TO IMPROVE SAFETY: The safety procedures in force at the sites are working as demonstrated by the fact there have been no accidental release of chlorine at either site within the last five years. There are no planed changes to the safety program. |