TRAITEMENT DES MARGINES PAR UN PROCEDE COUPLANT LA COAGULATION FLOCULATION ET LA VOIE ELECTROCHIMIQUE

Abstract

The purpose of this study is the treatment of olive wastewaters by the combination of two physicochemical processes: the coagulation, flocculation as pre-treatment and a treatment by electrochemical way as the process of refining. Olive wastewaters presented a chemical oxygen demand (COD) of 32,71 g of O2/l, an acid pH (5,02), and a dissolved oxygen of 0,5 mg/l and a concentration of polyphenols of 1,22 g/L. The tests of coagulation were realized by means of the bench of jar-test, established by a series of six flasks subjected to increasing doses of the coagulant (the sulfate of aluminium). The tests allow to eliminate 42% of the COD, 58% of suspended matter (SM), 22% of polyphenols, 83% of turbidity, and 42% of the coloring. The effluent pre-processed by coagulation, flocculation, which has an optimum dose of sulfate of aluminium, undergoes to filtration then handled by an electrochemical reactor; where the intensity in 5A, the tension 14V, the temperature 30°C, the speed of agitation 200 tr/min, and the salinity in 0,5 g/l. This electrochemical treatment allowed to reduce the color intensity by 86%, the COD by 30%, the polyphenols by 57% and the turbidity by 41%. It emerges from all the results that the treatment by coupling coagulation, flocculation and electrochemical processes allowed reach a COD of 9,11g d’O2/L, a SM of 0mg/L, a solved oxygen of 7,16 mg/L and a concentration of Polyphenols of 0,32 g/L.