Sulfamethazine removal by means of a combined process coupling an oxidation pretreatment and activated sludge culture – preliminary results

Abstract

A coupled electrochemical process and biological treatment was used to remove a biorecalcitrant antibiotic: sulfamethazine (SMT). The pretreatment was performed in a home-made flow cell involving graphite felt as a working electrode at potentials of 1 and 1.6 V/saturated calomel electrode (SCE); it was followed by a biological process involving activated sludge purchased from a local wastewater treatment plant. Activated sludge cultures of pretreated and non-pretreated SMT solution were carried out for 3 weeks, and different parameters were monitored, especially total organic carbon (TOC) and SMT concentrations. high-performance liquid chromatography results revealed that the target molecule was not assimilated by activated sludge. However, and confirming the improvement previously observed for the biological oxygen demand/chemical oxygen demand (BOD/COD) ratio, from 0.08 before electrolysis to 0.58 after electrolysis, a pretreatment step in oxidation at 1.6 V/SCE led to a fast decrease of TOC during the subsequent biological treatment, since the mineralization yields increased from 10% for a non-pretreated SMT solution to 76.6% after electrolysis in oxidation (1.6 V/SCE), confirming the efficiency of coupling the electro-oxidation process with a biological treatment for the mineralization of SMT. Moreover, when the electrolysis was performed at 1 V/SCE, no biodegradation was observed, underlining the importance of the electrochemical pretreatment.

Electrochemical Processes Coupled to a Biological Treatment for the Removal of Iodinated X-ray Contrast Media Compounds

“…To associate the benefit of a selective electrochemical processes and low expensive biological treatments (Assassi et al, 2011 ; Fontmorin et al, 2014b ; Belkheiri et al, 2015 ; Saidi et al, 2017 ; Zaghdoudi et al, 2017 ; Geneste, 2018 ), we investigated the coupling of both methods for the removal of the highly recalcitrant contrast agent, diatrizoate (DTR) ( Scheme 1 ). Graphite felt was used as a cost-effective porous electrode with high specific surface area in a flow-through system to improve the mass transfer, decrease the electrolysis time, and facilitate the industrial application of the electrochemical process.…”

Metallic nanoparticles for electrocatalytic reduction of halogenated organic compounds: A review

“…Electrochemical processes can also be used as pre-or post-treatment to directly oxidize or reduce organic compounds by tuning the potential or the current applied according to the target compound, hence making them more selective than AOPs. For example, processes based on electrochemical oxidation or reduction coupled with activated sludge treatment were reported for the removal of antibiotics and pesticides [16][17][18][19][20][21][22].…”