City of Altamonte Springs Water Treatment Plant #2 - Executive Summary
FACILITY DESCRIPTION |
The City of Altamonte Springs operates water treatment plants throughout the City. The function of these plants is to withdraw water from the Floridan Aquifer, remove odor and taste causing compounds (such as hydrogen sulfide) through aeration, disinfect through the use of chlorine gas, store, and supply potable water throughout the service area for domestic use and fire protection.
Chlorine gas, a hazardous and toxic chemical, is used because it provides the best balance of disinfection ability, ease of use, relatively low cost, and residual disinfecting power for the water treated and public served. Typically, the City will store up to 8,000 pounds of chlorine at the water treatment plant for current and future use. The City has provided disinfection with chlorine for the public water system for decades.
Chlorine is stored and used in a sealed building at the water plant. The building is protected by a gas detection system and is secured against intrusion. The en
tire plant site is surrounded by a secure fence. Any plant operation involving the use of chlorine (with the exception of delivery) is performed inside the building with the access doors closed.
ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES:
The City's overall policy with respect to chlorine gas is based around the need for conscientious storage, handling, and use of the chemical. The City has a comprehensive program of procedures related to chlorine designed to minimize the likelihood of exposure to our employees as well as the residents. Procedures in place for the Water Treatment Plant mandate the use of a specialized team of employees who are the only persons allowed to handle the containers or equipment.
The procedures are based, in part, on the most stringent requirements of the OSHA Process Safety Management rule, although the City is not required to comply with the rule at that level.
In addition, the City has installed chlorine neutralizing devices ("scrubbers
") at the water plants. In the event of a release, the system is designed to seal the storage room, and activate a mechanical/chemical device that reacts the chlorine with sodium hydroxide, to produce salt water. These systems are designed to neutralize over 99.5% of the chlorine that could be released from a one-ton container.
Emergency response, in the event of a release, is handled through a formal Emergency Response Plan enacted by the City several years ago. The City of Altamonte Springs Fire Department serves as the initial responder in the case of all emergency calls from a Utility facility, including the water plant. In the event that a hazardous release has occurred, the Fire Department will mobilize the Seminole County Hazardous Materials (HAZMAT) response unit. The County HAZMAT team will perform coordination of response, public communication, recovery and cleanup activities.
CHEMICAL RELEASE SCENARIOS:
As part of the procedure to prepare this Risk Management Plan (RMP), th
e City has undertaken a rigorous review of the required worst-case and alternate release scenarios for the chlorine at the water plant. These scenarios are reviewed to determine the offsite impact, if any, of such a release.
The "worst-case" scenario involves the loss of all the contents of a one-ton container of chlorine, which is the largest single storage unit held by the City. Under regulatory requirements, this scenario assumes that the worst possible combination of release rate, weather conditions, and release location occur. If a release were to occur in this "worst-case" mode, an area outside the plant site would be affected.
The City believes that the risk associated with such a scenario is negligible, since the conditions leading to this type of release are considered to be extremely rare. To have an outdoor release, the event leading to the release could only occur during the delivery of the full containers. The City, as part of its Accident Prevention Program, requires that
the persons delivering chlorine to the water plant be trained in the safe handling of chlorine containers. The chlorine producers, through their Chlorine Institute, have developed packaging, inspection, and transportation standards designed to maximize the safe handling of chlorine in public areas.
The most likely form of release involves a container leak as a result of a severely corroded container or a faulty supply valve. The Chlorine Institute standards provide protection against corroded containers and it is the City's policy to reject any container exhibiting traits of a defective valve. The City's procedures mandate that the connection of chlorine cylinders to the disinfection system be performed only with all doors to the outside closed. In the event of a leak, the gas concentration detectors would sound an alarm. The alarm, in turn, will turn the ventilating fans off and the chemical scrubber on.
The City considered two alternate release scenarios, one of which is included in
this RMP. The first scenario (not included in this RMP) assumes that the release occurs inside the closed building and that the alarm system and scrubber function as designed. Under this scenario, there would be no offsite impacts of a release. The second release scenario assumes that an access door is not properly secured and remains open during a release. The alarms and scrubber will still activate, but the lack of a sealed airspace would hamper the effectiveness of the scrubber. A relatively small amount of gas would escape leading to a small area of offsite impact.
FIVE-YEAR ACCIDENT HISTORY:
Over the last five years, the City of Altamonte Springs has not experienced an accidental release of chlorine.
ACCIDENTAL RELEASE PREVENTION PROGRAM:
As mentioned earlier, the City has implemented a stricter level of safety procedures and policies than required by state and federal rules. Specifically, the City is implementing a program designed to minimize the likelihood, and potential imp
act, of accidental releases. Specific elements of the program include regular process hazard analysis, training, contractor safety programs, regular review and updating of operating procedures, maintenance programs to enhance mechanical integrity, self-administered compliance reviews, and management of change.
Each of the individual elements is supported by an organization framework in which key employees are given responsibility for RMP elements. This management program includes mandatory review and documentation procedures to ensure future safety as the plants and processes change.