Electrochemical treatment of rice grain-based distillery effluent: chemical oxygen demand and colour removal

The electrochemical (EC) treatment of rice grain-based distillery wastewater was carried out in a 1.5dm(3) electrolytic batch reactor using aluminium plate electrodes. With the four-plate configurations, a current density (j) of 89.3A/m(2) and pH 8 was found to be optimal, obtaining a maximum chemical oxygen demand (COD) and colour removal of 93% and 87%, respectively. The chemical dissolution of aluminium was strongly influenced by initial pH (pH(i)). At higher pH(i) (pH 9.5) anode consumption decreased while energy consumption increased. At the optimal current density 89.3A/m(2), the aluminium electrode consumption was 16.855g/dm(3) wastewater and energy consumption was 31.4Wh/dm(3) achieving a maximum COD removal of 87%. The settling and filterability characteristics of electrochemically treated sludge were also analysed at different pH. It was noted that treated slurry at pH(i) 9.5 gave best settling characteristic, which decreased with increase in pH. EC-treated effluent at pH(i) 8 had provided best filterability. Characteristics of scum and residues are also analysed at different pH.