OPTIMIZATION OF COAGULATION PARAMETERS IN THE REMOVAL OF TURBIDITY AND SUSPENDED SOLIDS FROM TANNERY EFFLUENTS USING THE BOX - BEHNKEN DESIGN

Abstract

The present study evaluated the performance of tannery effluent treatments by coagulation processes. This was done by combining each of the organic coagulants L-1544, L-1541, and L-1700 with aluminium sulphate, respectively, as an inorganic coagulant in different mixing ratios. Subsequently, the response surface method optimized the coagulation conditions: agitation speed, time, and total coagulant concentration. The best results were obtained with the cationic coagulant based on L-1544; likewise, by superposition of contours plots, the conditions that maximize the percentages of simultaneous removal of turbidity and suspended solids were determined, the optimum coagulation values being time 4 minutes, agitation speed 169.7 rpm and total coagulant concentration 1354 ppm, obtaining 100 and 61.9 % removal of turbidity and suspended solids respectively. The R-Squared statistics show that the models explain 92.99 % and 93.94 % of the variabilities in turbidity and Suspended Solids Removal, respectively.