A PANEL OF LUMINESCENT BACTERIAL BIOREPORTERS FOR DETERMINATION OF TOXICITY MECHANISMS IN ELECTROCHEMICALLY-TREATED INDUSTRIAL WASTEWATER

Abstract

Wastewater from industrial processes can contain a wide variety of organic species, often in high concentration and difficult to treat. Advanced oxidation processes (AOPs), based on the in-situ generation of hydroxyl radicals, can help with complete mineralization. During the treatment, however, the generation of toxic intermediate can take place, which would hinder the application of AOPs as a pre-treatment. The evolution of toxicity in electro-Fenton (EF) treatment of industrial wastewater was evaluated with a panel of bioluminescent bioreporter bacteria capable of differentiating the target of damage, with light emitted and bacterial growth absorbance monitored. The bacterial panel was able to identify a pattern of affected structures in the cell by the wastewater. From comparison with possible by-products of the treatment, formaldehyde was identified by the toxicity pattern. Chemical analysis confirmed the accumulation of formaldehyde to over 1000 ppm during electro-Fenton, not observed in other studies on similar wastewaters.