Estudo da eficiência da tratabilidade de efluentes de CIP da indústria de produtos lácteos

Abstract

The effluent from the CIP, a sanitation system, represents a large part of the total dairy wastewater. In addition, they can be very polluting due to the high organic load typical from these industries and the chemicals used. One of the alternatives for the treatment, advantageous for its simplicity, is coagulation and flocculation. Natural coagulants have been receiving attention because they are less expensive and toxic than conventional inorganic ones. Thus, coagulation and flocculation were studied using alginate extracted from the algae Sargassum filipendula, the seeds from the Moringa oleifera Lam and the iron magnetic nanoparticles functionalized with Moringa extract as coagulants for the removal of color and turbidity. The study of the alginate coagulant involved several concentrations at 3 pHs. For the Moringa seed coagulant, the use of different salts (NaCl, KCl, MgCl2 and CaCl2) was investigated in its preparation compared to its aqueous extract at pH 9 and in its natural pH. It was verified the salt concentration in the preparation of the extract and, finally, the sedimentation kinetics was investigated in the best condition obtained. The iron nanoparticles were functionalized with the best extract obtained for the Moringa seeds and had their study similar to the seeds themselves. The alginate and the Moringa aqueous extract were not satisfactory. Among the extraction salts, the one that provided the best results was the calcium chloride, used in the subsequent steps. Results of 92% of turbidity removal and 86% of color removal with Moringa concentration of 1000 mg L-1 extracted with 0,4 M solution of CaCl2 with 60 minutes of sedimentation were achieved. Under similar conditions of concentration, plus 50 mg L-1 of nanoparticles and sedimentation in external magnetic field, similar results of turbidity and color removals, 88% and 89%, respectively, were obtained in only 7 minutes of sedimentation. The phytotoxicity bioassays with the Lactuca sativa bioindicator demonstrated that the treatment does not alter the toxicity of the effluent. Thus, it was concluded that the nanoparticles functionalized with Moringa saline extract in CaCl2 represents an efficient primary treatment because it provides good results in a very short sedimentation time, in addition to being demonstrated that the nanoparticles can be recovered after the treatment by sludge regeneration.