All carwashes operate using a considerable amount of water, and many are making the decision to reclaim the water, usually because of economics or environmental and regulatory issues.

However, dealers who sell reclaim systems to carwash operators should be aware of a potential problem.

Many water treatment dealers are familiar with — and have treated for — the presence of Legionella in cooling tower water. However, what may not be as widely known is that Legionella bacteria can develop in reclaim systems used at local carwashes.

Legionella is most commonly transmitted through aspiration, meaning it can be a particular risk when present in mist form. Consequently, it is imperative that Legionella not be allowed to develop in carwash wash or rinse water.

Water treatment dealers who sell reclaim systems to carwashes can help their customers. Reclaim manufacturers offer a variety of solutions for keeping wash water free of Legionella bacteria. With a little vigilance and the right solutions, you can keep the wash water safe for carwash customers and employees.

"It’s obvious that carwash water is a perfect breeding place for bacteria development," says Gertjan Spaans, international sales manager for Dutch reclaim manufacturer Rowafil Water Recycling. "Temperature, stagnant water and relatively warm places like sand filters and clogged carbon plates are excellent circumstances for pathogen bacteria growth."

Analyzing the problem

Spaans says that fears over Legionella outbreaks have led some European trade shows to restrict how some water-distribution systems such as reclaim equipment can be displayed. The crackdown is occurring as the result of a 1998 Legionnaire’s outbreak at a flower show in Holland, which claimed the lives of 28 people.

The European Working Group for Legionella Infections, a British research firm that tracks cases of Legionnaire’s disease in Europe, says only four out of every million people contract Legionnaire’s disease, which will initially cause flu-like symptoms.

Spaans also is careful to point out that the presence of Legionella bacteria will not always lead to illness. Some scientists claim that 20 percent of Legionella bacteria is harmless, while 60 percent is dangerous mostly for individuals with weakened immune systems. In addition, a recent audit of several Shell stations that currently use Rowafil systems found no presence of Legionella bacteria.

Howard Taylor, president of Catec Water Recovery Systems, Sarasota, FL, also believes that Legionella may not pose a frequent threat to carwash reclaim systems, but he advises dealers to take preventative measures to ensure that this bacteria does not develop and colonize.

"The airborne bacteria must be inhaled in reasonably large concentrations in order to affect humans, so it is very unlikely that the small amount of bacteria present in a carwash operation would find the proper conditions for all this to occur," he says. "Personally, I have never heard of a Legionella case being tracked to a carwash operation. Still, there is always a possibility that all the conditions are met."

Containing Legionella

Because Legionella is such a dangerous bacteria, water treatment manufacturers have developed several ways to destroy the bacteria and inhibit its growth. Most reclaim manufacturers rely on chlorine, aeration, ozone and biological treatment to eradicate Legionella from wash water.

Chlorine is one of the most controversial methods for treating reclaim water against the Legionella bacteria. Many carwash owners use liberal amounts of chlorine to eliminate pit and reclaim odors and kill bacteria. However, chlorine can be damaging to metal parts and studies show that it does not prevent the rapid reoccurrence of Legionella colonies.

"Most of the carwash owners put chloride and other additives in the pits to avoid or reduce the bad smell on site," says Spaans. "Especially in the summertime, they are not aware that the bacteria are more or less being activated, causing a fast increasing anaerobic stage."

Constant water circulation and aeration can go a long way toward preventing the stagnant conditions in which Legionella can thrive. Most reclaim manufacturers recommend water circulation, and some prescribe oxygen aeration, although Spaans warns that some systems may not use enough oxygen to effectively kill all Legionella.

Many reclaim systems use ozone to minimize bad odors and destroy bacteria, such as Legionella. Although ozone can be damaging to rubber parts in high enough concentrations, most manufacturers say it reacts and dissipates too quickly to cause serious problems. Ozone is a proven Legionella killer, and Taylor says some systems have been used to eliminate bacteria in considerably larger applications, such as cooling towers.

Spaans expects some manufacturers to move toward biological solutions for destroying Legionella and other bacteria. Rowafil currently uses a combination of oxygen and vitamins, which accelerate biodegradation. Although Spaans says the company is happy with the results, he admits the technology still has not gained widespread acceptance in the US market.

"It is our opinion that the industry should be more open and less prejudiced against bio treatment," he says. "We are dealing with a biological problem. We are now convinced that this can be solved only in a biological way."

Taylor says that no method of bacteria elimination should replace periodic testing of wash water, especially if dealers fear that bacterial development may be occurring.

"If there is a suspicion of bacteria multiplication, then it would be beneficial for the carwash operator to have periodic testing done on his carwash and waste water," Taylor says.

Kevin Hart is an editor at National Trade Publications, which publishes Water Technology.