Tratamento do soro do leite por simbiose levedura-microalga em reator coluna de bolhas

Abstract

The industrial sector has been highlighted due to its growth and contribution to economic development and in this environment the food sector has shown great relevance. This growth has generated a high amount of liquid and solid waste that needs treatment before being released into the environment so that it does not cause damage to soil and water. Among the fastest growing sectors in Brazil, there is the dairy industry, which represents a very important activity for this sector, although it generates great environmental impacts related to the incorrect release of solid waste and liquid effluents. Whey, a by-product from cheese production, is generated in high quantities and has a great polluting potential due to its high organic load, therefore, it is necessary to treat this effluent properly before discarding it and causing damage. Studies that enable alternative measures, such as bioremediation, have been developed to reduce contamination of the environment. The use of the yeast-microalgae consortium has been studied for its low cost and viable application, in addition to presenting a high level of nutrient removal (nitrogen and phosphate) and being efficient in reducing the concentration of Chemical Oxygen Demand (COD). In this context, the present study aimed to evaluate the treatment of whey (80762.87 mg.L-1 of COD, 1373.73 mg.L-1 of total nitrogen (TN) and 602.84 mg.L-1 of total phosphorus (TP)) by symbiosis using the yeast Saccharomyces cerevisiae and the microalgae Tetradesmus sp. in a bubble column reactor. The experiment was configured in batch with different organic loads (0.5, 1, 2 and 4%) applying a light intensity of 100 µmol m-2 s-1 and aeration of 0.5 vvm. The results showed that the consortium presents greater efficiency, reaching the removal of 94.07% for COD, 83.61% for NT and 95.18% for TP. The system using only the yeasts obtained removal efficiency of 78.22, 77.56 and 58.09% for COD, TN and TP, respectively. In the consortium, the biomass growth was maximum after 96 hours of experiment for all concentrations, while the monosystem presented variations, in 0.5%, maximum value was after 72 hours, in 1% after 96 hours and, 2% and 4%, after 168 hours of experiment. Thus, bioremediation through yeast-microalgae presents itself as a possibility to reduce the organic load and adjust the whey to the levels required for release into water bodies.