Hidden Spring Water Production Facility - Executive Summary
Orange County Utilities (OCU) owns and operates the Hidden Springs Water Production Facility (WPF), located at 7490 Conroy-Windermere Road in Orlando, Florida. |
Like the majority of municipal water treatment plants in the United States, gaseous chlorine is used at the Hidden Springs WPF as a disinfectant to destroy pathogenic organisms in the treated water. The popularity of chlorine as a water disinfectant is mainly due to its effectiveness and ability to provide a measurable residual.
The same properties that make chlorine valuable as a disinfectant also make it necessary to observe certain safety precautions in handling chlorine as a safeguard to our workers, our community, and the environment. Chlorine is notably irritating to the eyes, nose, throat and lungs. More serious human health effects could result from much higher chlorine exposure, such as intense coughing, chest pains, and in extreme cases, death.
Orange County's commitment at the Hidden Springs WPF is to store, han
dle and use chlorine in a manner that achieves the needed benefits of disinfection 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 providing an emergency response capability to minimize the consequences of a chlorine release, should a process accident ever occur.
Accidental Release Prevention and Emergency Response Policies
It is Orange County'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 accidental release prevention and emergency response.
The primary measures for accidental chlorine release prevention are contained in the document entitled Program 2 Risk Management Program for the Hidden Spring
s Water Production Facility. This process safety management (PSM) document was prepared in conformance with the EPA risk management rules, as well as industry-specific guidelines and best management practices relevant to release prevention. Hidden Springs WPF's Section Manager has the responsibility for ensuring that this program is implemented in the workplace as written.
The Hidden Springs WPF emergency response plan relies on a team of offsite mutual-aid groups such as fire and rescue services. The emergency response plans at Hidden Springs WPF are based on the Incident Command system, where onsite responders work in coordination with local hazardous materials response teams to implement the OCU and regional response plans. Hidden Springs WPF's personnel receive hazard awareness training to understand how to recognize emergencies and to initiate the Incident Command system.
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 chlorine 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 inside a building equipped with a chlorine detection system that immediately notifies the operators of a release should a leak occur. Two cylinders are connected to the disinfection process: one is in-use, and one is as standby. The standby cylinders will automatically switchover when the in-use cylinders become empty, ensuring continuous disinfection. The maximum intended chlorine inventory at Hidden Springs WPF is 5 cylinders, or 10,000 pounds of chlorine stored in the building.
The Worst-Case and Alternative Chlorine Release Scenarios
As part of Hidden Springs WPF'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 Hidden Springs WPF'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 worst-case situation results in a distance to chlorine endpoint (defined as 0.0087 milligrams per liter) of 0.9 mile.
EPA defines an alternative release 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 (chlorine detection, operator response, etc.) are considered in this scenario. The scenario involved the release of chlorine gas through a failure of an lead washer on the gas cylinder connection. Response time
is conservatively assumed to occur in 45 minutes. This scenario results in a distance to chlorine endpoint of less than 0.1 mile. This distance does not account for the fact that the building is enclosed to prevent chlorine gas from escaping the chlorine storage area.
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
OCU's PSM document contains 8 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 chlorine process, 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 chlorine process.
*Training programs: Training is given to each employee assigned to the process with continuing operator training thereafter, with an emphasis on safe chlorine handling and emergency response.
* Mechanical integrity: The integrity and reliability of the process is maintained by implementing preventive maintenance and routine inspection and testing procedures.
* Incident Investigation: OCU 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 recurrence.
The above elements are only part of OCU's aggressive safety program. In addition to the Program 2 elements, OCU has established related OSHA safety programs such as hot work and confined space. These OSHA safety programs apply to both OCU and con
Five-year Accident History
There have been no accidents involving chlorine at the Hidden Springs WPF in the past five years.
Emergency Response Program
The emergency response plan covers all aspects of emergency response including escape procedures and routes, procedures for post-evacuation employee accounting, notification procedures, rescue and medical duties, and response procedures for spills or leaks. If a major chlorine leak were to occur, the emergency plan requires immediate notification of the regional hazardous materials response teams for assistance, including orderly evacuation or sheltering-in-place of the surrounding community.