OPTIMIZATION OF COAGULATION PRETREATMENT OF A REAL DAIRY EFFLUENT USING A RESPONSE SURFACE METHOD

Abstract

This paper proposes a pretreatment of a real dairy effluent by coagulation and decantation using two types of coagulants, aluminum sulfate (Al2(SO4)3) and ferric chloride (FeCl3). In order to optimize the best coagulation conditions leading to maximums of COD and turbidity removals, response surface method (RSM) was employed. The analysis of variance showed that the values of the correlation coefficients (R2) for the reduction of turbidity and COD were found equal respectively to 0.959 and 0.840, which gives an idea about the validity of the quadratic developed models and their predictive qualities. The results predicted by the models were 98.18 and 77.06% of turbidity and COD removals, at Al2(SO4)3 concentration of 1200mg/L and time of treatment of 38.57min. These results are in agreement with those obtained experimentally.