Harnessing Microalgae Photobioreactors to Address Rising Sludge and Fouling Challenges in Membrane Bioreactors

This study explored the application of microalgal engineering in a photobioreactor to mitigate rising sludge and fouling issues in a Wastewater Treatment Plant (WWTP). By introducing microalgae into the activated sludge of a Moving Bed Biofilm Reactor (MBBR), this study aimed to enhance the dissolved oxygen content within the MBBR, which was a critical factor for optimizing the reduction of Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) in wastewater. During the microalgae cultivation phase, Chlorella sp. was cultured with adding nutrients, including urea and TSP. Upon reaching a sufficient Mixed Liquor Suspended Solids (MLSS) concentration, microalgae were inoculated into the MBBR. The research results demonstrated an improvement in the quality of the effluent and a reduction in rising sludge within the clarifier, coinciding with an increase in dissolved oxygen content exceeding 2 mg/L. Cost-benefit analysis revealed a significant reduction in WWTP operational costs, primarily due to the discontinuation of two blowers that were previously operated. This study encourages the utilization of microalgae in MBBRs as a potential solution to reduce operational costs in the wastewater treatment industry.