Evaluation of sodium ferrate as an efficient coagulant for total suspended solids and nematode removal from water

This study aimed to investigate the effect of sodium ferrate (SF) on total suspended solids (TSS) and nematode removal from surface water. Response surface methodology was used to optimize the operational variables such as pH, dosing rate, rapid mixing time, and gentle mixing speed on TSS and nematode removal. The optimum conditions of independent variables including SF dosage, pH, rapid mixing (time and speed), and gentle mix speed were found to be 1.558 (mg/L), 6.5, 30 s at 120 rpm for coagulation followed by 20 min of gentle mix. TSS and nematode removal of 90.76 and 98.04 were observed for SF in optimized conditions, respectively. SF demonstrated 4.3% and 5.76% more TSS nematode removal at a lower dosage compared with poly aluminum chloride, polyelectrolyte, and primary and secondary ozonation. Economic analysis showed that the application of SF instead of using conventional chemicals provides a significant reduction in operational costs to around 65%, which mainly belonged to the reduction of chemicals and energy consumption.