An estimated 5 billion pounds of soiled linen is processed annually by approximately 7,300 hospitals in the United States. As many healthcare laundries are being replaced by contract services, there is greater demand for wash processes that are cost effective, environmentally responsible and meet regulatory requirements.

Laundry companies have become increasingly interested in using ozone systems for a substantial amount of laundry operations and investigating the feasibility of this application may help your commercial customers.

Why use an ozone system in a laundry plant? Some of the benefits may include:

SYMBOL 183 \f "Symbol" \s 13.5 Cleaner water going into sanitary sewer systems.

SYMBOL 183 \f "Symbol" \s 13.5 Potentially shorter cycle times, which lead to more pounds processed per day, less labor used, less energy consumed and lower equipment costs.

SYMBOL 183 \f "Symbol" \s 13.5 Reduces the amount of detergents used in current processing methods, perhaps by as much as 50 percent. This should also lead to extended linen life and a significant reduction in rag-outs.

SYMBOL 183 \f "Symbol" \s 13.5 Chlorine bleach is replaced with hydrogen peroxide, which may produce fewer rag-outs and extend linen life.

SYMBOL 183 \f "Symbol" \s 13.5 A substantial reduction in plant hot water usage as much as 80 percent leading to less energy usage.

SYMBOL 183 \f "Symbol" \s 13.5 Bacteria are inactivated and odors reduced.

Ozone, an energized form of oxygen, consists of three oxygen molecules. It is 15 times more powerful a disinfectant in water than chlorine. Ozone molecules have weak bonds with the third oxygen atom. With this structure, the ozone molecule has a positive charge (because it is electron-deficient), strong oxidizing power and is highly reactive in nature.

Ozonated Water Attacks Stains

Ozone often is produced when oxygen is exposed to an electrical discharge through dry air, which occurs during on-site ozone generation. Ozone gas is then mixed with water supplied to the washer extractors.

When the ozonated water reaches the water extractors, it transforms soil from an insoluble to a soluble substance, which allows the soil to be loosened and removed from textiles.

Organic and hydrocarbon stains carry a negative charge, and since ozone has a positive charge, there is a magnetic attraction between ozone and soil. As a result, the soil molecule is oxidized, which makes it more soluble in water and easier to precipitate.

The soil molecules are polarized, which breaks down large molecules into smaller ones, making them easier to remove from textiles. As lint and other particles are generated, they are removed from the wash water through a series of filters. The recycled water is then reozonated and used for the next wash cycle.

Because ozone has already helped remove some soil from textiles and the particles are much smaller, surfactants are much more efficient at removing the rest of the soil. The amount of surfactants can be greatly reduced from the amount used in conventional washing operations. Also, wash cycle times are decreased because of shorter formula times.

But what about bacteria and other microorganisms? Ozone ruptures cell membranes and kills bacteria within two seconds of contact, compared to conventional chlorine, which diffuses through the cell wall and takes up to 60 minutes.

One of the disadvantages of using an ozone system is that rewash rates may be higher in some laundry plants. But, taking into account through less energy consumption and lower costs in treating discharge water, ozone may still be advantageous.

According to results from a 1994 membership survey conducted by the American Society for Healthcare Environmental Services (ASHES) of the American Hospital Association, nearly half of U.S. health facilities operate an in-house laundry facility on premises, processing laundry at an average cost of 29 cents per pound and distributing it at an average of 22 cents per pound.

As healthcare costs continue to rise, ozonating your customers' laundry plants may be profitable.

Bruno Giacomuzzi works for the Electrical Power Research Institute's Healthcare Initiative, White Plains, NY.