Treatment of Anaerobically Digested Distillery Spent Wash Using Electrocoagulation with Al-SS-Al Electrode Configuration

The sugarcane-based distillery plant generates the anaerobically digested distillery (AnDD) spent wash after distillation and bimethanation, also known as a recalcitrant. The AnDD contains complex constituents of many hazardous matters, which results in high chemical oxygen demand (COD) and colour, causing a threat to the environment and aquatic life. The researchers found treating such recalcitrant challenging. In this study, a promising technology, electrocoagulation (EC), has been used to treat such wastewater before discharging it into the environment. Optimising different operating parameters allows the EC process to effectively remove the colour and COD consuming less time and power. This study presents a novel approach for the degradation of such recalcitrant through the EC technique with two aluminium (Al) and one stainless steel (SS) as anodes and a cathode, respectively. Two Al-anodes used both surfaces of the SS-cathode to save the treatment cost, and the cathode, which was not consumed during the reaction. Therefore, the objective of this study was to observe the effects of different operating parameters on the Al-SS-Al electrodes' configuration for the treatment of AnDD spent wash. The main operational parameters for the EC process, such as reaction time (0-270 mins), current density (0.0022-0.0132 A/cm(2)), inter-electrode distance (10-30 mm) and dilution ratios (AnDD: DI = 1:3-4:0), were studied. The optimum conditions: 150 min, 0.0088 A/cm(2), 20 mm and 1:3 were found using the one factor at a time (OFAT) method. The maximum COD, colour, turbidity, TDS and TSS removal were 84.64, 91.37, 86.92, 29.2 and 77.62%, respectively. The anode and power consumptions at optimum conditions were calculated as 4325 mg/L and 60 Wh/L, respectively. The overall treatment cost was calculated as 0.021 USD/L. Results proved that the EC process with Al-SS-Al electrodes configuration has high removal efficiency at reduced treatment cost for AnDD spent wash.