Treatment of Baker’s Yeast Wastewater with Freshwater Microalga and Its Green Chemistry Evaluation

Abstract

Baker’s yeast production processes require great amounts of high quality water, where it yields in formation of molasses wastewater and resistant COD (Chemical Oxygen Demand). The Chlorella variabilis microalgae application is studied and evaluated in this paper. The aim was to feed microalgae with the nutrients sustained by molasses; therefore, it was expected an observable growth of them and cleaning of the wastewater. Sample wastewater was 1- centrifuged to remove suspended solids, 2- diluted to various ratios, 3- incubated to grow microalgae, and 4- centrifuged to remove grown microalgae. Final analysis showed the efficiency of COD removal had been maximum 93.33%. The greenness of the method was evaluated by examining the process with respect to principles of green chemistry. It is concluded that the proposed biotechnological approach satisfies 8 principles of green chemistry.