2D and 3D electrochemical degradation (ECD) of raw cotton industry wastewater (CIWW) using stainless steel and aluminium electrodes

Abstract

Abstract Two-dimensional (2D) and three-dimensional (3D) batch electrochemical degradation (ECD) of raw cotton industry wastewater (CIWW) was adopted using stainless steel (SS) and aluminium (Al) electrodes. ECD as a treatment option was aimed at removing priority quality parameters, viz. chemical oxygen demand (COD), colour, chloride, nitrate, etc. COD removal of 85 and 80% were achieved by using 3D SS and 2D SS electrodes operated at 6 V (0.9 A) for a maximum electrolysis time (ET) of 30 min. Similarly, 76 and 70% COD removal were achieved for 3D Al and 2D Al electrodes, respectively. Simultaneous colour removal in the 2D ECD system using SS and Al electrodes was low by 12 and 11% compared to the 3D ECD system. Water quality parameters, viz. total dissolved solids, chloride, nitrate, phosphates, and sulphate were also removed by 3D (SS and Al) and 2D (SS and Al) electrodes. Higher pollutant removal efficiencies were observed at 30 min ET for 3D SS electrodes compared to 2D SS, 3D Al, and 2D Al. Post-ECD slurry showed good settling characteristics for SS electrodes generating dense and sturdy flocs giving a low sludge volume index values for 2D SS electrodes compared to other electrode options.