Thursday, June 01, 2006

The West Palm Beach water treatment plant uses chlorine as a disinfectant. This is combined with ammonia to produce the relatively stable chloramines disinfectant, a commonly used method. Disinfection is the most important step in disease prevention. The chlorine form used by this plant is pure chlorine gas, liquefied under pressure in steel cylinders. Any leaks from these containers can be very deadly. The cylinders in one ton and 150 pound sizes are stored in a concrete walled building. The large cylinders are hooked up to piping in two banks of six cylinders each. There are two piping systems: One to take the gas upper phase; another to take the lower liquid. The liquid line goes through an evaporator for the conversion to gas. Down stream, the chlorine is metered and mixed into water and pumped to an in-plant water contact point. The chlorine storage area is fitted with a scrubber system. If a leak occurs, detectors in the room sound an audible alarm , a signal to a computer monitoring system and also turns on the scrubber. The scrubber is designed to neutralize the contents of a one ton chlorine cylinder by mixing the air drawn from the room into a large vat of sodium hydroxide. The neutralized air is then exhausted to the atmosphere. The four exit doors to the storage room and the two exit doors to the metering/pump room are protected by high tech cyber key locks.

The above is a well thought out system that is relatively safe if maintained properly. However, it is not!

The gas phase pipe system has a blockage and the piping is not usable. The gas phase of the cylinders is connected to the remaining line intended for liquid. That sends the chlorine through an evaporator. The evaporator had a leak last week. The leak continued for half a day until repaired. The chlorine disinfection was discontinued during the time it took to plug the leak.

The scrubber has a hole in the contact chamber. When operating, sodium hydroxide sprays out of the unit. So the scrubber is inoperative awaiting repair.

There is a valve separating the two banks of cylinders. It is electrically operated and has a leak that feeds back chlorine to the bank not in service.

Chlorine is a strong oxidizing agent. It supports combustion. Oily rags, wood, and hydrocarbons such as oil or grease can ignite in the presence of chlorine. During time of emergency such as a hurricane, a truck and trailer carrying a motorized airboat are stored with the chlorine. Currently, bags of carbon are being stored there. The following inquiry was sent to the Chlorine Institute (the trade group sponsored safety group). The reply will be reported here when it arrives.

“I am a licensed water treatment plant operator. My question: Is there anything wrong with storing bags of granulated or powdered carbon in a chlorine tons (for chlorine gas in one ton cylinders) storage room? The West Palm Beach water treatment plant in the state of Florida is doing just that. I contacted their risk management group. Result: my complaint was ignored. I contacted the local office of the state health department. They think it is ok. I think that a chlorine leak could ignite most hydrocarbons, including dry carbon. I have not preformed the experiment and never intend to, but that is what the above mentioned groups are doing. What does the Chlorine Institute say about this?”

There are other problems: The cyber key door lock system is defective. Most of the doors cannot be opened from the outside with the key. Those that do open often require repeated tries.

Chlorine in the 150 pound cylinders is used throughout the distribution system and is located at the repump stations. Leaks are common as the station hook ups need replacement. To their credit, the Town of Palm Beach does not permit the use of chlorine in gas cylinders within the town. The two repump stations in Palm Beach are serviced with liquid bleach.

How dangerous is a chlorine leak? The West Palm Beach water treatment plant has from 12 to 18 full cylinders and about that many nearly empty cylinders. The gas is heavier than air. Each cylinder has six plugs intended to melt in the heat of a fire. Twelve hooked up cylinders can leak out in a piping leak (recall that the valve between the banks of 6 has a leak and cylinders are hooked up in a manifold of 6). In a fire, up to 36 full and partial cylinders can leak. More than eighteen tons of chlorine released at once! The gas is heavier than air. It will move with the wind. Much like the mustard gas of World War II, it can kill or maim all those in its path.