Separação de microalgas através de membranas de osmose inversa e cerâmica com aproveitamento do permeado para futuros cultivos.

Abstract

In last recent years , a high interest in the biotechnological potential of microalgae was noted, mainly due to identifying several substances synthesized by these organisms . Their huge biodiversity allied to genetic improvement and establishing cultivation technology on a large scale used to allow microalgae to be used in various applications , specially in treatment of wastewater from industrial processes , mitigating the greenhouse effect by assimilating carbon dioxide (C02 ) and the biofuels production, such as biodiesel and ethanol. Moreover, in microalgae production, we noted some problems during separation with a view to the need to preserve biomass, particularly as regards to the characteristics phones. Among the various microalgae separation methods, in which are the most commonly centrifugation used, such as filtration and flocculation and in certain cases where the dimensions are very small, the separation through rennet addition is used, which are constituted by metal salts which can damage the chemical composition of the cell and prevent the use of medium after separation. So it's necessary to seek new techniques for microalgae separation that do not modify its characteristics, such as the case of separation processes that has the advantage not to break the cell structure and to allow greater separation depending on the microalgae's porosity, and beyond, the permeate from separation can be reused as a mean of cultivation of microalgae. In this context, this study aims to evaluate the potentiality of using reverse osmosis membranes (RO ) and Ceramic membranes for separing microalgae Chlorella sp reusing the culture medium derived from the separation in order to reduce operating costs and impacts by inappropriate release of waste liquid into the soil . Daily monitoring of algal growth was performed after inoculation through cell density elaborating growth curves from aliquots drawn in triplicate of photobioreactors and erlemeyeres daily, we also made the chlorophyll and productivity for each sample studied . We obtained good results on both separation types, comparing the reuse of the addition of 250mL and 500mL of the RO permeate into the inoculum volume, we reached a population of 3,3x107 cel.mL"1 and 2,86x107 cel.mL"1, respectively , whereas for separatin by Ceramic membrane using the same RO conditions, we obtained growth of 4,1x107 cel.mL"1 for 250mL permeate and 3,40x107 cel.mL"1 for the 500 mL permeate. Regarding production versus energy consumption, the membrane separation by RO presented an energy absorption of 3,96Kw.h/m3 while we obtained 0,510Kw.h/m3 for the Ceramic membrane process, showing therefore a very promising alternative , since there was a greater energy costs reduction and a higher cell productivity, thus making it a technology economically and environmentally correct in microalgae Chlorellas sp cultivation and separation.