Performance of different coagulants in the coagulation/flocculation process of textile wastewater

A comparative study of the efficiency of different coagulants in the textile wastewater treatment was carried out. The utilization of natural coagulants instead of the synthetic ones has demonstrated significant advantages since it provides a low cost and environmentally friendly technology for removing dyes. This study aimed at evaluating the performance of different coagulants in the removal of the apparent colour, turbidity, absorbance, and COD of textile wastewater samples from an industrial laundry. Two organic coagulants (Moringa oleifera Lam seeds extracted in saline solutions of NaCl and KCl 1 mol L−1) and an inorganic coagulant (aluminium sulphate) were used. Initially, the influence of the pH was evaluated for each coagulant. Then, a factorial design was applied in order to determine the coagulant concentration and the sedimentation time needed for the textile wastewater treatment. All the parameters obtained their best results with acidic pH values for the studied coagulants. The organic coagulants presented the best results, in general, reaching removals of 82.2% for the apparent colour, 83.05% for COD, 78.4% for RP-HE7B, and 89.7% for OP-HER using the Moringa coagulant extracted in KCl. This study demonstrated the applicability of the Moringa oleifera Lam seeds to the textile wastewater treatment.