Ultrasonic cleaning uses water and sound waves
In an effort to purge hospitals of superbugs, contractors are using ultrasonic cleaning techniques. But these aren't limited to the health service, and can even be used on your office keyboard.
By Denise Winterman
BBC News Magazine
Soap, water and old-fashioned elbow grease - that's how we used to get hospitals clean. Now, the buzzword is "deep cleaning".
Office bosses are among the latest converts to deep cleaning. In an era of hot desking, workstations have a hard life. They're used every day, often by different people. Keyboards, mice and other equipment become breeding grounds for bacteria.
Ultrasonic cleaning - a technique that's being used in the NHS's £50m deep clean programme - is unleashing something of a revolution in the cleaning world. It works by transmitting ultra-high frequency sound through heated tap water, which contains special detergents.
Move over Kim and Aggie, here comes the science
This causes microscopic bubbles to form in every crevice of the submersed piece of equipment, known as cavitation. The bubbles collapse almost immediately and these thousands of implosions per second result in the deep-cleaning action.
The equipment is dipped several times for up to 10 seconds. A heated blow gun is used to take off excess water and the equipment is then placed in a special drying oven.
Despite water being involved in the process almost anything can be ultrasonically cleaned, from televisions and computers to toys and wedding dresses. Only materials such as paper and wood, which swell in water, are beyond the ultrasonic range.
"It really is amazing technology," says Stephen Yendley, director of Ultrasonic Machines UK Ltd. "The science behind it was first used in World War I to clean weapons. It's a good tool for hospitals to fight bugs.
"Almost anything can be cleaned this way and it is environmentally friendly," he claims. "It uses tap water with only two chemicals added and sound waves. The water doesn't need any specialist treatment after the cleaning has been done, it can just go down the drain."
In one experiment carried out by the company, a plate tested after being cleaned in a dishwasher still had 1,759 bacteria on it. This is an acceptable amount, but the plate washed using ultrasonic technology had just 45 bacteria left.
Many hospitals and other businesses are only just becoming aware of the uses of ultrasonic cleaning. But one area where it is already very popular is fire restoration.
"Often things recovered from a fire are still in good working order but just badly soiled," says Mr Yendley. "Ultrasonic equipment is great for cleaning it all up. It's good environmentally as well because you are reusing stuff, not replacing it."
With the increasing spread of highly drug-resistant bugs, like MRSA, proper cleaning is becoming increasingly important. But ultrasonic cleaning is just part of solution, regular cleaning and maintenance is also needed.
"We talk about standards of cleaning but I don't think a lot of people have them anymore, they just do what they think is enough - no more than that," says Mr Yendley.
"Cleaning properly and regularly is also vital."