Efficient Blackwater treatment via nanoparticles chemical coagulation enhanced by different coagulant aids

Abstract Most common technique for eliminating various pollutants from wastewater is chemical coagulation. In the present study, the municipal wastewater was separated at the source into blackwater (BW) and greywater (GW). BW is known to be affected by organic load. In the present study, BW was subjected to different chemical coagulants and coagulant aids for safe reuse after removing of pollutants, including the organic contaminants, by chemical coagulation process. In this study, titanium dioxide (TiO 2 ) nanoparticles (NP) and different coagulants, namely: Al 2 (SO 4 ) 3 and/or FeSO 4 , were examined for treating of BW. For this purpose, different TiO 2 -NP doses, varying from 40 to 120 mg/l, were examined to evaluate the efficiency of treatment. It was found that TiO 2 -NP nanoparticles worked perfectly to remove the organic load of BW at optimum dose of 80 mg/l. These nanoparticles demonstrated promising results, where the removal of COD and TSS reached 80.69% and 95.56%, respectively. However, these nanoparticles exhibited lower efficiency for PO 4 3- removal (namely, 12.96%). These findings suggest that TiO 2 -NPs have the potential to be effective and strong alternative to traditional coagulants for BW treatment. By using other coagulants, Al 2 (SO 4 ) 3 and/or FeSO 4 , alongside with optimum dose of TiO 2 -NPs, provided a distinct advantage in BW treatment. Each coagulant contributes unique chemical properties that influence coagulation in terms of efficiency, settling rates, and quality of the final treated effluent. Therefore, the present investigation highlights the potential of utilizing coagulant aids in conjunction with TiO 2 nanoparticles to achieve a more comprehensive and efficient treatment of BW for safe reuse.