Hornsby Bend Biosolids Management Facility - Executive Summary |
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HORNSBY BEND BIOSOLIDS MANAGEMENT FACILITY CITY OF AUSTIN, WATER AND WASTEWATER UTILITY RISK MANAGEMENT PLAN (RMP), EXECUTIVE SUMMARY Accidental release prevention and emergency response policies at the plant: The City of Austin Water & Wastewater Utility (Utility) owns and operates Hornsby Bend Biosolid Management Facility (Hornsby Bend Facility). The Utility's mission is that it will protect our community's public health and environment by effective management of our water resources. The Hornsby Bend Biosolid Management Facility has established an effective chemical release prevention and emergency response plan. It is the policy of the Hornsby Bend Facility to take all necessary actions to prevent the release of a hazardous chemical. Even with an effective prevention program in place, a chemical release incident may still be a remote possibility. Through planning, procedures, training, and monitoring, the facility is prepared to promptly perform emergency actions to minimize and contain the release of a hazardous chemical. Highly trained Hornsby Bend Facility employees with the aid of City of Austin Fire Department Hazardous Materials Team are prepared to respond to the scene, evacuate the immediate area (if necessary), and control a release. The stationary source of the chemical and the name of the regulated chemical handled: Hornsby Bend Biosolid Management Facility is a state of the art composting facility. Biosolids are taken from three wastewater treatment plants and processed into compost. The material is then sold to local landscaping contractors for soil treatment. Nothing is wasted at this plant. In the process of treating biosolids, methane is generated and stored in eight digesters. Each digester contains 17,100,000 lbs. of biosolids. The maximum amount of methane calculated in a single digester at the facility is 6,100 lbs. The methane is used to operate boilers that heat the solids in the digesters to accelerate their breakdown. Th e methane is also used as fuel for two large motors, which drive generators and supplies electricity to operate several plant systems The worst-case release scenario including administrative controls and mitigation measures to limit the distance for each release: The Environmental Protection Agency (EPA) defines a "worse-case" scenario as the release over a 10 minute period of the largest amount of a listed chemical under very extreme weather conditions and with the total, simultaneous failure of all active safety and emergency backup systems and personnel. The probability of this scenario is so extremely remote that EPA's basic intention is to identify any potential offsite impacts. The facility defines its worst case scenario as the total release of methane contained in one digester due to an explosion without consideration of any active mitigation system. The EPA developed model, RMP* Comp Version 1.06, was used to calculate endpoint distance reported in the plan. The facilit y reports that the potential for offsite public and environment impact does not exist. Administrative controls are placed on the amount of methane stored at the plant. This includes a minimum amount of methane required to process the biosolids and operate the plant. There are many safety devices to prevent explosions from occurring. Isolation "valving" (valves used to stop the flow of methane from one digester to another), safety gas burners, pressure release valves and many types of instrumentation monitoring devices are used to mitigate the possibility of a methane explosion. The plant is also staffed 24 hours per day constantly monitoring the plant. The general accidental release prevention program and prevention steps: The Hornsby Bend Biosolid Management Facility has established a comprehensive accidental release prevention program that includes highly motivated and trained employees who continually inspect and maintain the plant safety gas system in top-notch condition wh ich reduces the potential for an explosion release to equipment malfunction. The operators and maintainers at the plant are continuously retrained in the safe and proper operation and maintenance practices needed to prevent them from making any human errors, which could also, result in an explosion. The five year accident history: The Hornsby Bend Biosolid Management Facility has not had a chemical release or explosion in the last five years. Under normal operations the safety gas burners and pressure relief systems are primarily used as a precautionary measure to prevent dangerous situations. The emergency response program: The Hornsby Bend Biosolid Management Facility has established an emergency response program which involves training of employees and a partnership arrangement with the Austin Fire Department Hazardous Materials (AFD HazMat) Team. The Utility has spent considerable time, money, and effort to train every employee at the facility to respond to a chemical r elease. All facility employees have received Hazardous Waste Operations and Emergency Response (HAZWOPER) awareness, operations, or technician level training. Selected employees have received extensive training in emergency response from AFD HazMat instructors equal to that received by the HazMat Team. In case of a hazardous chemical release, the facility operators would determine the severity of the situation and if warranted, would call the HazMat team to respond to the facility. After an assessment of the situation has been made by AFD and facility personnel, a partnered response to alleviate the problem would be performed. This partnership makes the best use of the expertise of facility employees and HazMat team. Planned changes to improve safety: The plant is upgrading the process monitoring system, which would allow the plant operators to view process information at a computer console. This would reduce the need to send a plant personnel to the digester to determine the s everity of the problem. Thus, reducing the risk to plant personnel to injury. The facility is continuously evaluating new safety systems, process control equipment, and procedures that would improve the safety of the employees, the public, and the environment. |