From drain to gain: the hidden treasures in wastewater
By MICHAEL ALLEN
EU industries from food and drinks to chemicals and biotechnology are seeking to profit from materials in water after it has been used.
For decades, most of the wastewater from the Mahou San Miguel brewery in the northeastern Spanish city of Lleida was flushed down the drain.
Now the effluent is being used to generate power and heat for the brewery, which is taking part in a research project that received EU funding to make wastewater a reusable resource.
Bits for biogas
Mahou San Miguel, Spain’s top beer producer, is using water to clean the Lleida brewery as well as to wash out fermentation tanks and old bottles before recycling and refilling them.
As a result, the wastewater is full of organic matter — so-called biomass — like old beer and bits of hops and grains that can be turned into biogas.
‘You have energy in the wastewater in the form of biomass or heat, which you can recover,’ said Dr Anne Kleyböcker, a researcher at the KWB water-research centre in Berlin, Germany.
She said industrial wastewater also contains other materials such as nutrients that could be economically valuable as long as ways can be found to extract them.
