A study of the coagulation/ adsorption process to remove heavy ion metals from wastewater of ship repair industries using water jet pressure

Abstract

Attempt was made in this study to examine the efficiency of PAC, bentonite and chitosan dose for coagulation process to remove heavy ion metals from wastewater of ship repair industries using water jet pressure. Experiments were set up using standard jar test procedures to determine the performance of adding of (i) PAC and bentonite, (ii) bentonite and chitosan, (iii) PAC, bentonite and chitosan. In the first combination of PAC and bentonite, the removal efficiency for Zn, Cu , Pb and Cd in the wastewater were obtained at 230 mg/l for PAC and 20 mg/l for bentonite. In the case of bentonite and chitosan combination, the removal efficiency of all elements were obtained at 200 mg/l for bentonite and 10 mg/l for chitosan. For the combination of PAC, bentonite and chitosan, the removal efficiency was obtained at 160 mg/l for PAC, 20 mg/l for bentonite and 10 mg/l for chitosan. Adding of PAC in the presence of bentonite resulted in significant removal of the heavy metals reaching up to 99%, 97,5%, 78,3% and 69,4% of total Zn, Cu, Pb and Cd respectively while adding of bentonite and chitosan achieved only 80,4%, 72,0%, 45,7% and 39,8% of total Zn, Cu, Pb and Cd respectively. Combination of PAC, bentonite and chitosan at different ratios enhanced removal efficiency of the metals (99,5% for Zn, 97,5 % for Cu, 87,5 % for Pb and 78,6 % for Cd). From the results obtained it could be concluded that the combination of PAC, bentonite and chitosan at suitable ratios can be used to remove the heavy elements in the wastewater by the coagulant/adsorption process with high removal efficiency.