Evaluation of total suspended solids removal in coal mine wastewater by chemical and electrochemical methods

Abstract

This study presents results on the application of chemical and electro-coagulation (EC) treatments for Total Suspended Solids (TSS) removal in high level TSS coal mine wastewater. The objective was to select optimal coagulant type and dosage, electrodes material and current density for enhanced TSS removal. The optimal dosages of chemical coagulants were determined to be as follows: 0.12 g/L- aluminium sulphate (alum), 0.05 g/L - Polyaluminum Chloride (PACl) and 0.025 g/L for cationic Polyacrylamide (PAM) and Polydiallyldimethylammonium chloride (PDADMAC), at which TSS removal exceeded 99%. Whereas the optimal current densities in electrocoagulation were 10 mA/cm² and 15 mA/cm² for aluminium and iron electrodes, respectively. In terms of the coagulants cost and efficiency evaluation, PACl showed to be the optimal choice with excellent TSS removal efficiency of 99.7% at the total treatment cost of RM 0.08/m3. Overall, this study demonstrated that chemical coagulation remains preferable treatment for high TSS removal from actual coal mine wastewater in terms of efficiency and cost.