Jul 10, 2020

Researchers Use Electricity to Break Down Pollutants

A study used electricity to break down pollutants left over after wastewater treatment

wastewater pollution

Professor Patrick Drogui of the Institut national de la recherche scientifique (INRS) and his team tested the effectiveness of a tertiary treatment process using electricity. 

This was done in partnership with the European Membrane Institute in Montpellier (IEM) and Université Paris-Est. The full study can be found here.

The advanced electro-oxidation process (EOA) uses two electrodes to break down non-biodegradable pollutants remaining after biological treatment, according to Phys.org. When electric current is passed through the electrodes, hydroxide radicals (OH) are generated.

An advantage of this method is that it does not require any chemicals to be added to the water.

The researchers tested new catalytic electrodes, discovering that these electrodes produce large quantities of hydroxide radicals. They are also cheaper than the other electrodes currently on the market, according to Yassine Ouarda, Ph.D. student and first author on the study.

"EOA processes are revolutionary in the field of wastewater treatment. It's pioneering technology for treating wastewater contaminated by refractory pollutants such as pharmaceutical wastes," said Professor Patrick Drogui, co-author of the study.

Researchers tested the technology on water coming from different treatment processes: conventional, membrane bioreactor, and a treatment process that separates wastewater, including feces, at the source. They focused on paracetamol, or acetaminophen, reported Phys.org. 

"We tested the process on this particular molecule because it's one of the world's most widely used drugs. We have already tested it at INRS for some 15 different pollutants, as the process can be used for other pharmaceutical molecules," Ouarda said.

The study confirms that advanced electro-oxidation processes are good candidates for breaking down drug wastes left behind after biological treatment, reported Phys.org.

"We observed that the toxicity of the solution increased and subsequently decreased during treatment. This indicates that the toxic molecules themselves are broken down if the reaction continues," Ouarda concluded.

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