Since the ban on ozone depleting CFC 113 in October, virtually all of the UK's 6,500 dry cleaners rely on perchloroethylene (ENDS Report 309, p 51 ). But the industry is under pressure to eliminate emissions of the solvent. In July, the Department of the Environment, Transport and the Regions (DETR) signalled that to comply with the 1999 EC Directive on solvent emissions, it intends to oblige all dry cleaners to obtain official registration and satisfy rules on managing emissions (ENDS Report 306, pp 31-32 ).
Dry cleaners will have to meet gradually tighter emission limits until 2007, when they will have to use "closed cycle" machinery which recovers all perchloroethylene for recycling. Although such machines are on the market, only a minority of UK establishments have so far fitted them, given the 20-year average lifetimes of existing machines.
In contrast, in Germany and Switzerland, where stringent emission controls were introduced some time ago, closed cycle machines are now standard.
Electrolux-Wascator says it hopes to be ready in a year's time with machines that will give dry cleaners a more sustainable alternative to perchloroethylene technology.
It is carrying out trials with machines using liquid carbon dioxide in combination with specially developed detergents. The company has yet to carry out a full life cycle inventory of its technology compared with perchloroethylene, hydrocarbon or wet-cleaning concepts. But it has compared their energy requirements and found that, despite needing compressors, its new technology requires far less energy because it operates at ambient temperature.
Anticipating other environmental arguments against the technology, Electrolux says the CO2 will be obtained from fermentation or from power plants where it would have been emitted anyway. "It's a zero-sum game," project manager Sten-Håkan Almström told ENDS. He added that the detergents used with the technology had been chosen for their biodegradability as well as their performance.
CO2 will not perform as well on heavy greasy stains as perchloroethylene. On the other hand, Mr Almström points out, it can be used on leather and heavily dyed fabrics where perchloroethylene cannot. Electrolux's aim is to produce a machine that matches the costs of perchloroethylene when capital and running costs are taken into account. It does not think that the market will sustain a premium for a more environmentally friendly service.
Mr Almström envisages that the company will first promote its technology to large dry cleaning chains in countries that already have strict legislation. The UK market is unlikely to be a front-runner, he said. But he feels it is only a matter of time before dry cleaners across Europe will be forced to abandon perchloroethylene, either because of higher direct costs - some countries are planning to tax solvent emissions - or due to the cost of meeting strict emission limits. "When you talk to legislators in just about any country, they say it's not a question of if, but when perchloroethylene will go," he said.
Another factor will be the commercial realities of sustaining perchloroethylene in a dwindling market. A spokesman for the European Chlorinated Solvents Association (ECSA) told ENDS that, as a result of the solvents Directive, sales of perchloroethylene are expected to drop by 80-85% by 2007 from the 74,000 tonnes sold in 1999.
One major producer, Italian firm Enichem, has already pulled out of the market, leaving five - Dow Europe, ICI, Solvay, Ercross and Atofina.
Perchloroethylene, although sold cheaply, provides an attractive option for getting rid of residues from the production of other chlorinated chemicals. It offers an income as opposed to the significant costs of disposing of such residues. It is likely that some firms will seek to continue producing the chemical.
Indeed, the industry is still keen to defend the merits of its product. ECSA's latest newsletter features a life-cycle analysis commissioned by Dow Europe which, ECSA says, found that "textile cleaning with perchloroethylene is as environmentally friendly as wet cleaning and cleaning with hydrocarbons." The study, carried out by the Swiss Federal Institute of Technology, compared hydrocarbon technology with modern closed-cycle perchloroethylene machines.
However, ECSA's article omits to mention that the study also looked at liquid CO2, and concluded - with a caveat that the technology is still at development stage - that "carbon dioxide dry cleaning looks better from an environmental point of view."