Bob Derrington Water Reclamation Plant - Executive Summary |
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The City of Odessa operates a wastewater treatment plant located southeast of the City in western Midland County. Chlorine is used to disinfect the effluent, for algae control, and control of sludge bulking. Residual chlorine in the effluent is removed using sulfur dioxide prior to discharge from the plant to the receiving stream. Chlorine is currently stored onsite in one ton containers up to a maximum of 20,000 pounds. Sulfur dioxide is currently stored up to a maximum of 4,000 pounds. Due to the presence of these chemicals at the facility, the City of Odessa has developed a program to ensure the safe handling of the chemicals. The safety program has been reviewed in accordance with the Environmental Protection Agency's Risk Management Program and revised to comply with its provisions and enhance the existing program. The City of Odessa is committed to allocating the manpower and financial resources required to implement all facets of the Risk Management Program and thereby r educe the potential for an accidental release of any toxic substance. An off-site consequency analysis was conducted by the independent consulting firm of Alan Plummer & Associates using a computer air dispersion model (ALOHA). The analysis defines the area potentially affected by the release of a toxic substance allowing the identification of residential populations, public and environmental receptors such as industrial and commercial, and natural environmental sites such as parks. The worst case scenario assumes a 2,000 pound release within a 10 minute period with a wind speed of 1.5 meters/second, an "F" stability class, and urban topography. Using this criteria, the Plant to the endpoint was determined to be 2.1 miles. Alternative release scenarios were considered for chlorine and sulfur dioxide simulating a broken line or valve on the chlorine system using wind speeds of 3 meters/second, a "D" stability class, and urban topography. These scenarios resulted in toxic endpoints of 1.6 and 1.2 miles from the Plant. Similar criteria for sulfur dioxide resulted in a toxic endpoint of 1.8 miles from the Plant. As a part of the City's Risk Management Program, the City reviewed a five-year period to determine if any accidental releases or incidents which could have resulted in an accidental release had occurred. No incidents were identified. The Accidental Release Prevention Program for the City of Odessa contains several facets. The chemical storage areas were designed in accordance with the Standard Building, Plumbing, Mechanical, and Gas codes, as well as the National Electrical Code. The established maintenance program ensures that the equipment is maintained in a manner which allows its safe operation. Standard operating procedures have been developed for the delivery of the hazardous gases, operation of the chlorine and ammonia systems, management of change to processes, and the investigation and correction of leaks. Training programs have been estab lished to ensure that employees have initial and ongoing training in the operation and maintenance of the hazardous gas system and proper response to an accidental release. This training not only includes plant personnel but also other personnel (e.g. Fire Department and contractors) who are instrumental to the overall success of the safety and emergency response programs. To ensure continued compliance with the conditions of the prevention program, periodic compliance audits will be conducted and any deficiencies addressed. An emergency response program is also in place. Trained plant personnel will address minor leaks while the Emergency Response Team of the Fire Department will address major leaks. Leak detectors are in place that will alert plant personnel and Emergency Services of a leak. Emergency Services will dispatch the Fire Department and notify key personnel. If needed, the public in the affected area can be alerted through the Community Alert Network (CAN) or simila r system. The Emergency Plan has also been coordinated with the Ector County Local Emergency Planning Group. An in-house hazard evaluation of the toxic gas system has been conducted and araeas of improvement determined. In response to these findings, improvements to the leak detection system, standard operating procedures, and emergency resonse program have been implemented. In summary, the City of Odessa has implemented a Risk Management Plan as defined by the Environmental Protection Agency to address a potential accidental release from the chlorine and sulfur dioxide systems operated at the Bob Derrington Water Reclamation Plant. The complete report is on file at the City of Odessa Utilities Department. |