Dram of the clean stuff

The medicinal powers of whisky have long been reputed, but a new technology from Scotland uses a by-product from the liquor to cure contaminated groundwater.

Researchers at Aberdeen University have developed a land decontamination process based around a whisky by-product, called draff — the spent barley left after the fermentation process.

Known as Device for the Remediation and Attenuation of Multiple (DRAM) pollutants, it claims to be the first decontamination technology that can treat a variety of degrading organic pollutants, such as pesticides, and remove metal contaminants at the same time.

The draff is encased in a perforated stainless steel cylinder device that goes to work as soon as it is dropped into contaminated water.

‘It’s almost like a giant tea bag,’ said one of the project’s principal investigators, Prof Ken Killham.

The by-product creates a microbial population and anaerobic conditions that biologically break down pollutants and immobilise harmful metals like chromium.

The cylinder devices would be lowered into the groundwater through boreholes and released at a pre-determined depth. Killham said different types of contaminants are found at different depths, so the users would have to know what they are looking for.

Pre-field trials of DRAM conducted on the west coast of Scotland have shown a 99.96 per cent success rate. Field trials are now about to begin in Glasgow.

Other processes used to clean up sites require expensive equipment to excavate the land. Sometimes the cost of this — together with deadlines for remediation — means the land is too expensive to clean up.

‘Whenever you excavate it gets very expensive because of the cost of digging up or pumping out hazardous materials and transporting them to landfill,’ said Killham.

Moreover, existing decontamination technology involves injecting expensive and potent chemicals into groundwater. ‘You’re just compounding one problem with another problem,’ said Killham.

The time it takes for the DRAM technology to work depends on the extent of the contamination, the size of the area and the speed of the groundwater flow.

‘If you have a site that has slow flow, this process could go on for a few years,’ said Killham. ‘And where you have rapid flow it might just take weeks.’

Yet speed doesn’t matter too much. ‘There is nothing to stop the site being used while the process is being used,’ said Killham. ‘With techniques where you have to dig up the site, that is not the case.’

The technology has massive potential for industry, its developers claim. Groundwater contamination is a major problem and can hold up or even prevent land development. It can also be a hazard to health and the environment.

The research team estimated that in the UK there are 330,000 contaminated sites, and the country annually spends £1.2bn on land remediation or clean-up.

Killham said the applications could go beyond groundwater. ‘All kinds of waste water could be treated,’ he said. ‘It could possibly be used to treat urban waste water or water in water treatment plants.’

While the new technology has so far only used a whisky by-product the tests demonstrate the technique could also deploy other by-products from food and drink production.

The Speyside distillery Glenfiddich has helped the Aberdeen researchers get to this stage by donating the draff used in the technology.

Killham along with his university partners, Graeme Paton and Leigh Cassidy, are considering forming a spin-out company to commercialise the technology that could be licensed to land consultants and other companies involved in remediation.

They are now preparing to do field trials in central Scotland —where the land is polluted with the remnants of the once thriving chemical and steel industry.

Killham said the best part about his group’s contamination device is that it is making use of a waste product. ‘It’s quite attractive to use a waste to solve a problem,’ he said.