## 1 Introduction  
Water pollution caused by the discharge of textile wastewater (TWW) is considered a serious environmental problem. TWW contains various dyes, salts at high ionic strength of about 5 to 6% NaCl and 5% of Na\({}_{2}\)SO\({}_{4}\), and other chemicals, such as various acids, alkalis, sulfur, naphthol, surfactant-dispersing agents, formaldehyde-based dye fixing agents, and heavy metals [1, 2]. World production of industrial synthetic dyes is estimated at more than 700,000 tons annually and about 10% left as residue are discharged into water bodies. Azo dyes constitute the largest class of synthetic dyes and represent 70 to 90% of the total synthetic dye tuff market due to their color shades and low cost [3, 4, 5, 6]. The discharge of TWW has major environmental consequences such as eutrophication, oxygen depletion, and loss of soil productivity. In addition, most chemical dyes have various drawbacks that seriously affect human health. Indeed, azo dyes enter the body through ingestion and cause cancer and DNA diseases [7, 8].Some of the chemicals in TWW including dyes are recalcitrant in nature because of their stability in front of the washing processes and therefore required treatment by appropriate and effective methods prior to their release into the environment. Physical methods such as coagulation, flocculation, and filtration, chemical oxidation by oxidizing agents such as O\({}_{3}\) and H\({}_{2}\)O\({}_{2}\), advanced oxidation techniques such as photocatalytic oxidation and fenton, and biological methods using microorganisms such as fungi, algae, and bacteria [9; 10; 11] are the main treatment strategies explored to date. Nevertheless, physicochemical methods are not widely adopted because of their secondary pollution generation, large time demand, and high energy consumption [12; 13]. Compared to conventional physical and chemical methods used for TWW treatment, microbial remediation is a suitable alternative that has the advantages of low operating costs (excluding aeration in aerobic bioprocesses) [14]. Unfortunately, microorganisms involved in the degradation of environmental contaminants generated by TWW have the shortcomings of a slow process [15]. The last few decades have seen the emergence of new bioelectrochemical systems (BES) aimed at reducing environmental impacts of hazardous and recalcitrant molecules such as dyes contained in TWW.Wu et al. [16] were the first to have successfully developed a BES for the continuous removal of Victoria blue R (VBR) dye applied in the textile industry and the simultaneous generation of electric current. The degradation rate of the dye was of 98.7% for artificial wastewater and 99.8% for real wastewater containing VBR. [PERSON] et al. [17] also demonstrated that BES are a very effective method for removal of dyes, TDS (Total Dissolved Solid), TSS (Total suspended solids), COD (chemical oxygen demand), sulfates, and chlorides from sugar wastewater. Similarly, [PERSON] et al. [18] reported the degradation of Congo red using glucose as co-substrate and found 97% removal efficiency for 300 ppm of dye. [PERSON] et al. [19] generated electricity from the co-oxidation of simple substrates and azo dye in a single chamber microbial fuel cell (MFC). They found that glucose compared to acetate was the best co-substrate for ABRX3 decolorization. Recently, complete decolorization of the azo dye methyl orange using an electrochemical approach was recently reported in the study by [PERSON] et al. [20], as well as an 83% reduction rate of total organic carbon using a simple Cu sheet as a working electrode. Despite several exploratory or applied works that have been carried out on the decolorization of azo dyes by BES, no specific research has focused on the degradation of Tubantin blue (TB) and Bezaktiv Red (BR), which are plentiful in TWW due to their intensive use by textile industries.