Influence of Coagulants in the Chemical Flocculation Process of Pollutants from Petrochemical Wastewater

This study investigated the optimization of chemical methods for the removal of petrochemical pollutants from wastewater. The novelty of this research lies in identifying the optimal concentration of coagulants, particularly the combination of IP1140 polyelectrolyte with Fe2+ ions. Five identical reactors were tested using a mixture of FeSO4 (3%), IP1140 polyelectrolyte (0.2 ppm), and Ca(OH)2 (20%) in different molar ratios per 100 mL (v:v:v): 1:1:2, 1:2:2, 2:1:1, 2:1:2, and 2:2:1. Parameters, such as the pH value, COD, BOD, the amount of extractable, and residue, were evaluated. The results demonstrated that after 10 min, the pH increased from 6.5 to 6.8 in reactor A and to 7.2 in reactor E. After 30 min, the pH values ranged from 7.0 to 7.5, reaching a maximum of 8.5 in reactor E after 120 min. The chemical treatment resulted in COD reductions of up to 89% in reactor B and 91.8% in reactor C; BOD reductions of up to 76% in reactor B and 87% in reactor E; extractable substances were reduced by up to 92% in reactor D and 88% in reactor A; while residue decreased by up to 87% in reactor B and 84% in reactor D. The BOD/COD ratio ranged between 0.3 and 0.5, with the best chemical treatment ratio carried out in reactor E with molar ratio/100 mL (v:v:v) 2:2:1.