Combined chemical oxidation and biological processes for herbicide degradation

Abstract

BACKGROUND Fenton and photo‐Fenton processes were explored as photochemical pre‐treatments to improve the biodegradability of wastewater containing atrazine, a commercial pesticide. The effects of H2O2, Fe3+ and irradiation level on the degradation processes were studied and the optimal conditions determined. RESULTS Fenton and photo‐Fenton oxidation systems were able to remove 85 and 100% of atrazine, respectively, in a 120 min period. These processes produced a biocompatible solution, removing 100% of the initial biorecalcitrant compound; however, cyanuric acid remained in the effluent after the chemical oxidation treatment due to the stability of the N‐heterocyclic ring of this acid. Nevertheless, it was found that the cyanuric acid remaining from the photo‐oxidative process can be removed by means of an anaerobic treatment. CONCLUSIONS The results obtained in this work indicate that a coupled photo‐Fenton–biological treatment system is a feasible method to achieve the complete mineralization of biorecalcitrant pollutants such as atrazine. © 2015 Society of Chemical Industry

Combination of chemical and biological processes to enhance the treatment of hardly biodegradable matter in industrial wastewater: Selection parameters and performances

“…The latter is then effectively treated via a biological process using a pure strain bacterium, Klebsiella terragena . Benzaquén et al showed that Fenton or electro‐Fenton pre‐treatments of wastewater containing atrazine, followed by a biological step, lead to complete mineralization. Thus, atrazine is removed by Fenton oxidation, while residual cyanuric acid is biologically oxidized with a degradation rate of 95 %.…”

Advanced Oxidation Technologies to Remove Endocrine Disruptors in Water Effluents Based on Zinc Supported Mesoporous Catalysts

“…The potential effects of these emergent contaminants in water are still uncertain and further investigation is needed to improve their efficient removal from water. Advanced Oxidation Processes (AOPs) are efficient and effective technology for water treatment that allow the total or partial removal of recalcitrant organic pollutants resistant to conventional treatments (Benzaquén et al 2013;Pignatello et al 2006;Benzaquén et al 2015). Among the various AOPs, heterogeneous Fenton like process in combination with UV-vis light is highly efficient in wastewater treatment.…”

“…Among the various AOPs, heterogeneous Fenton like process in combination with UV-vis light is highly efficient in wastewater treatment. These processes involve the generation of the hydroxyl free radical, which has a very high oxidation potential, by means of the use of strong oxidants (H 2 O 2 ), radiation ultraviolet, and catalysts (Benzaquén et al 2015;Chu et al 2007). The so-called heterogeneous Fenton-like systems use a solid catalyst in the presence of hydrogen peroxide.…”

Simultaneous photocatalytic and microbial degradation of dye-containing wastewater by a novel g-C3N4-P25/photosynthetic bacteria composite

“…Partly for this reason, most attempts to develop photocatalytic systems to treat dye-containing wastewater have focused on sequential coupling approaches [23–27,14]. A major complicating factor is that dye-containing wastewater often contains refractory and/or inhibitory organic compounds in a biodegradable matrix.…”

“…However, photocatalytic systems are indiscriminate; it is difficult to ensure that energy is not wasted by generating a series of products that are excessively oxidized or not readily biodegradable [ 21 , 22 ]. Partly for this reason, most attempts to develop photocatalytic systems to treat dye-containing wastewater have focused on sequential coupling approaches [ 23 – 27 , 14 ]. A major complicating factor is that dye-containing wastewater often contains refractory and/or inhibitory organic compounds in a biodegradable matrix.…”