Disinfected purified wastewater – an alternative source of water?

“Our motivation to start research on disinfected purified wastewater was the willingness to find an alternative source of water for agriculture. The solution seems interesting, but it is far from ideal,” says Dr Katarzyna Affek from the Faculty of Building Services, Hydro, and Environmental Engineering at WUT. Unfortunately, during the inactivation of disease-causing microorganisms, disinfection may lead to creating harmful byproducts, quite often even more ecotoxic than the purified wastewater itself.

In the research conducted at WUT, purified wastewater is disinfected by ozonising and dosing peracetic and performic acid. The impact these three methods have on the harmfulness of purified wastewater is analysed with conventional methods, which in eco-toxicology involve exposing different tested organisms to a range of concentrations of a given substance, or a mixture (in the case of wastewater a mixture is involved). Various effects are observed: survivability, impact on the growth of organisms, impact on the enzymatic activity, and manifestation in the entire organism.

Ozonation station, source: Magdalena Bińkowska

“In conventional tests, ozonated purified wastewater had the most harmful effect with respect to the bioindicators,” says Dr Katarzyna Affek.

Another step is molecular research, which aims to detect changes occurring in DNA, among other things. Thanks to the high sensitivity of these tests, substances that do not display ecotoxicity in conventional tests are proved to be mutagens, for instance, which during a long-term exposure may lead to changes in an organism, or in one generation of organisms but at times have an impact on the stability of the population or ecosystem as well.

“We have already conducted all planned conventional ecotoxicity tests. In a month, genotoxicity tests and research on the impact on the hormonal system will be conducted,” says Dr Affek.

Future plans

So far, Dr Katarzyna Affek has focused on testing ecotoxicity in her activities, without checking what produces a specific harmful byproduct. The scientist has started a collaboration with Katarzyna Lech, DSc, from the WUT Faculty of Chemistry within a research grant BEYOND POB, which will hopefully facilitate the identification of the formed byproducts soon.

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The project “Endocrine disruption, adverse effects of by-products and inactivation of pathogens during disinfection of treated wastewater” is funded as part of the BEYOND POB research grant under the Excellence Initiative – Research University programme implemented at the Warsaw University of Technology.

Research team:
Dr Katarzyna Affek; Katarzyna Lech, DSc; Magdalena Bińkowska, MSc