Removing toxic substances from water using hydrogen peroxide is a well-known and highly efficient method; however, one drawback is that it is very costly to first add the hydrogen peroxide and then remove what is left of it from the water. However, by using an electrochemical process, Professor Irini Angelidaki and her team at DTU Environment have successfully developed a method which—during the process—produces hydrogen peroxide, so that the water in the same apparatus is first cleaned of unwanted toxic substances, after which the hydrogen peroxide is burnt.
“The method works flawlessly. The apparatus comprises a water chamber divided into two compartments with two electrical components—an anode and a cathode—separated by a membrane. In the two different compartments, the hydrogen peroxide is first formed, which then burns all the organic contaminants in the wastewater such as toxic chemicals and bacteria. The process then changes so that the hydrogen peroxide is reduced to water. The method was tested with wastewater from different companies, for example in the pharmaceutical industry. In all the experiments, all the drug residues were completely removed, so it was not possible afterwards to detect a measurable content of the substances,” explains Professor Irini Angelidaki, DTU Environment.
The new method is very low-cost in operation, and will therefore revolutionize the market as the current water-treatment methods are very costly. Initial studies of the size of the market show that every year almost EUR 50 billion is spent on water treatment using hydrogen peroxide in the EU alone. The new method could cut costs by up to 90 per cent.
“The results of the trials look very promising. The method is very effective for all chemical compounds, which is incredibly important. In addition, it is financially attractive, as both cleaning the wastewater and transporting contaminated water to external treatment plants are costs which we and other types of companies would be very interested in seeing reduced,” says Steen Søgaard, Vice President, who heads the active pharmaceutical ingredient manufacturing facilities at Lundbeck’s production facilities in West Zealand.
Almost too good to be true
DTU Environment researchers are still very impressed with how well the new method works.
“It’s almost too good to be true. But now our 40-litre pilot plant has been running for the past six months, and neither the membrane between the two compartments nor the effectiveness of the treatment have deteriorated during this time,” says Senior researcher Yifeng Zhang who is responsible for the measurements.
Visually, it is also very clear to see how the turbid wastewater on the left-hand side of the plant is completely clean on the right-hand side.
Like so many other significant research breakthroughs, it happened slightly by chance. Two young researchers in Irini Angeladiki’s group often talked together, even though they worked in their own respective fields—with the Fenton method and bioelectric systems—and thereby found out that together they could solve the challenge by adding hydrogen peroxide for an efficient treatment process and then remove it again from the water.
The research group is now looking for funding and partners so their new treatment method can be completed and prepared for production and marketing.