Scientists at Heriot-Watt University have developed materials that can use wastewater from distilleries to produce green hydrogen. Whisky doesn’t just taste great, it could now help the environment
By Bill Heaney
Dumbarton used to be the capital of Scotch Whisky, but the drift away east and northwards of Allied Distillers and Strathleven Bonded Warehouses in the 1990s has reduced its stature to that of a major city on the whisky map.
There are still whisky distilleries around from Auchentoshan at Dalmuir Loch Lomond in Alexandria, but none as big as Allied Distillers in Castle Street Dumbarton, which has been replaced by Chivas Brothers bottling and packaging facility at Kilmalid, where 500 local people are employed.
Now is has been revealed that Scotland’s national drink could soon be used as an environmentally-friendly fuel. What impact that will have – if any at all – on the local drinks industry business people will have to wait and see.
But scientists at Heriot-Watt University in Edinburgh have developed materials that can use wastewater from whisky distilleries to produce green hydrogen which, unlike fossil fuels, does not produce carbon when it is burned.
Green hydrogen is normally created using fresh water in a process thought to consume around 20.5 billion litres of fresh water every year. The Heriot-Watt team hope the material they have developed will see some of the estimated one billion litres of wastewater produced by the distilling industry each year used to create green hydrogen instead.
Dumbarton was once home to the largest whisky distillery in Scotland.
This wastewater has caused problems with foul-smelling discharges at the Scottish Water sewage farm at Havoc on the banks of the River Clyde at Ardoch from time. Older residents will also remember the smell which emanated from the Castle Street distillery, the biggest in Scotland, from time to time.
Dr Sudhagar Pitchaimuthu, a materials scientist at the university’s School of Engineering and Physical Sciences, explained: “It takes nine kilogrammes of water to produce every one kilogramme of green hydrogen. Meanwhile, every one litre of malt whisky production creates about 10 litres of residue.
“To help protect the planet, we need to reduce our use of fresh water and other natural resources. So our research focused on how to use this distillery wastewater for green hydrogen production with a simple process that removes waste materials present in the water.”
Dr Pitchaimuthu and his team have developed a nanoscale material – a particle one in 10,000th the diameter of a human hair – to allow distillery wastewater to replace fresh water in the green hydrogen production process. The nanoparticle, called a nickel selenide, treats the wastewater and produces similar or slightly higher quantities of green hydrogen from the water during research compared to fresh water.
The research has been published in the Royal Society of Chemistry journal, Sustainable Energy and Fuels, in a paper authored by Dr Pitchaimuthu’s PhD student, Michael Walsh, who played a key role in conducting the research. “About one billion litres of wastewater a year is produced from the distilling industry, so the potential of this process is huge,” Dr Pitchaimuthu continued.
“Using industry wastewater means we can reduce the extensive freshwater footprint associated with green hydrogen production. Our research also shows how we can use the world’s resources more sustainably to produce clean energy.”
The next steps for the Heriot-Watt research team include developing their own electrolyser prototype and scaling up production of their nickel selenide nanoparticles. They will also analyse distillery wastewater to discover whether other materials of value could be salvaged from it, alongside hydrogen and oxygen.
Top of page picture: The landmark red brick mill building in Castle Street, Dumbarton, saw the whisky industry sadly move on from Dumbarton in the 1990s. Other pictures are of the ADL distillery from the River Leven and Littlemill distillery in Bowling.