Spend a penny, save a litre

The smallest room may seem to be an odd place for the highest tech, but one of the first nanotechnology innovations to hit the market is likely to have a major effect on public toilets.

A German firm, aquadry Deutschland, has developed a urinal whose nano-featured surface could dramatically reduce water consumption.

The coating exhibits what's known as the 'lotus effect', where a surface covered with microscopic hair-like structures interacts with the surface tension of water and other liquids. This forces the liquids to separate out into beads on the surface rather than 'wetting' it - that is, spreading out as a film.

Because of this, nothing contained within the liquid, such as bacteria, dirt, and substances which could stain or cause odours, can stick to the surface. The technique is being developed for self-cleaning coatings for building materials and glass, but when the liquid in question is urine, the bacteria and odour-repellant property obviously becomes valuable.

Conventional urinals are water-hungry, using very large amounts of water to flush and keep clean and therefore putting a strain on water treatment services. The aquadry dry urinal needs much less water and would therefore cut costs considerably.

The urinals are made from the engineering plastic ABS (acrylonitrile butadiene styrene), produced by Lanxess, formerly the plastics business of German major Bayer.

'We chose the ABS material mainly because the nano-coating adheres particularly well to the surface,' comments Günther Beiner, managing director of Lemgo, the firm which makes the plastic parts for aquadry.

Moreover, the material allows the urinal to be moulded with fittings which snap into place for easy installation and removal; it's also much lighter and easier to handle than the traditional porcelain or stainless steel.