Westside Regional Wastewater Treatment Plant - Executive Summary |
|
EXECUTIVE SUMMARY The City of Daytona Beach owns and operates the Westside Regional Wastewater Treatment Plant, located at 3651 LPGA Boulevard Daytona Beach, Florida. Like the majority of municipal wastewater treatment plants in the United States, gaseous chlorine is used at the plant as a disinfectant to destroy pathogenic organisms in the treated wastewater prior to discharge or reuse. The popularity of chlorine as a wastewater disinfectant is due to its effectiveness and relatively low cost compared to other disinfection technologies. The same properties that make chlorine valuable as treatment chemicals also make it necessary to observe certain safety precautions as safeguards to our workers, our community, and the environment. Chlorine is both notably irritating to the eyes, nose, throat and lungs. More serious human health effects could result from much higher chemical exposure, such as intense coughing, chest pains, and in extreme cases, death. The City's commitment at the Westside plant is to store, handle and use these chemicals in a manner that achieves the needed benefits of their use while minimizing both onsite and offsite risks. This is accomplished by designing a safe process, maintaining the process in optimum working condition, operating safely through documented procedures and extensive training, and arranging for the Daytona Beach Fire Department to provide an emergency response capability to minimize the consequences of a gaseous chemical release, should a process accident ever occur. Accidental Release Prevention and Emergency Response Policies It is Westside's policy to adhere to all applicable Federal, State of Florida and local rules and regulations. This specifically includes compliance with the Occupational Safety and Health Administration (OSHA) and Environmental Protection Agency (EPA) rules for chlorine. The primary measures for accidental chlorine release prevention are contained in the document Process Safety Managemen t Program for Westside Regional Wastewater Treatment Plant. This process safety management (PSM) document was prepared in conformance with the OSHA and EPA risk management rules, as well as industry-specific guidelines and best management practices relevant to release prevention. Westside's Plant Manager has the responsibility for ensuring that this program is implemented in the workplace as written. Stationary Source and Regulated Substances Handled Chlorine is received by the facility by truck and is stored in one-ton chlorine cylinders fabricated to Department of Transportation (DOT) specifications. Upon arrival at the site, all cylinders are thoroughly inspected and if there is any doubt about the integrity of the cylinder, it is promptly refused. Once accepted, the cylinders are stored under a shelter on a storage trunniuns. The standby cylinders will automatically switchover when the in-use cylinders become empty, ensuring continuous disinfection. The maximum intended chlor ine inventory at Westside is 10 cylinders, or 20,000 pounds of chlorine The Worst-Case and Alternative Chemical Release Scenarios As part of Westside's emergency prevention and response efforts, a hazard assessment was conducted in compliance with EPA requirements contained in 40 CFR 68, Subpart B. The hazard assessment included the development of worst-case and alternative release scenarios. EPA defines a worst-case release as a scenario involving the greatest amount held in a single vessel or pipe. In Westside's case, this involves the release of the entire contents of a one-ton chlorine cylinder. The release is assumed to occur over a 10-minute period. Applying the worst-case parameters to the Westside situation results in a distance to chlorine endpoint (defined as 0.0087 milligrams per liter) of 1.3 mile. In other words, any human or environmental receptors within 1.3 mile of the chemical storage building are within the worst-case distance. EPA defines an alternative rel ease as a scenario more likely than the worst-case, but that nevertheless results in an impact offsite (unless no such release is possible). Passive and active mitigation measures (gas release detection, operator response, etc.) are considered in this scenario. Without an accident history on which to base a more likely scenario, a scenario was selected based on information provided in the Chlorine Institute Pamphlet 74, Estimating the Area Affected by a Chlorine Release. The alternative-case of chlorine the scenario involved the release of gas through failure of a 0.25 inch whip leading to the gas cylinder. Response time is conservatively assumed to occur in 45 minutes. This scenario results in a distance to endpoint of less than 0.1 mile. There are no public or environmental receptors affected by this release. The distance to endpoint calculations were performed using EPA's RMP*Comp model. The RMP*Comp model was developed specifically for compliance with the accidental release prevention requirement for predicting the travel distance of an accidental release. General Accidental Release Prevention Program and Specific Prevention Steps Westside's PSM document contains 13 essential release prevention elements. Some of the key accidental release prevention elements of the PSM program are as follows: * Process hazard analysis: This analysis was performed for each step in the chemical processes to identify potential process failure scenarios and the appropriate prevention or response measures. The process hazard analysis will be updated every 5 years. * Operating procedures review: The review was conducted to ensure that operators are given clear, written instructions for safely operating the chemical processes. * Training programs: Training is given to each employee assigned to the process with continuing operator training thereafter, with an emphasis on safe chemical handling and emergency response. * Contractors: Westside ensures through i ts contract provisions that contractors supplying or working with chlorine is held to a standard of safety performance that complies with City's safety goals and objectives, and also meets relevant agency requirements. For example, City personnel make unannounced visits to the supplier's site to ensure that rules and guidelines concerning chlorine cylinder integrity are being followed. * Mechanical integrity: The integrity and reliability of the process is maintained by implementing preventive maintenance and routine inspection and testing procedures. * Management of Change: The management of change procedures provide a systematic approach to evaluate and control the safety and health aspects of any significant change to the process chemicals, technology, equipment and operating procedures. * Incident Investigation: The City investigates within 48 hours any accidents or "near misses" that could have resulted in a chlorine release, in order to develop measures to prevent a recurrenc e. The above elements are only part of the City's aggressive safety program. In addition to the 13 PSM elements, the City has established related OSHA safety programs such as hot work and confined space. These OSHA safety programs apply to both City and contractor employees. Five-year Accident History There have been no accidents involving chlorine at the Westside plant in the past five years. Emergency Response Program The emergency response plan covers all aspects of emergency response including escape procedures, notification procedures, and response procedures for spills or leaks. If a major chemical leak were to occur, the emergency plan requires immediate notification of the Daytona Beach Fire Department response teams for assistance, including orderly evacuation or sheltering-in-place of the surrounding community. |