Development of Low-Cost Aerobic Bioreactor for Decentralized Greywater Treatment

Centralized greywater treatment with aerobic activated sludge process normally needs a very large footprint which could be challenging in some places, such as in hilly and densely populated areas with limited vacant land. For these areas, decentralized wastewater treatment technology might be an appropriate solution for preventing pollution by greywater. This study presents the design of low-cost and simple aerobic bioreactor for greywater treatment. The bioreactor was equipped with a microbubble generator (MBG) as a highly efficient aerator and pumice stones for bacterial attachment media. The pumice stones served as immobilization media for activated sludge bacteria so that additional sedimentation step was not required and better effluent quality was achieved. We ran the MBG intermittently and investigated the optimum on–off interval which maintained the required level of dissolved oxygen (DO) with minimum energy consumption. The test also included chemical oxygen demand (COD) removal for the bioreactor performance evaluation. The bioreactor showed the potential to be used as a low-cost portable unit with easy operation and maintenance to make it suitable for greywater treatment at the household scale. © Springer Nature Singapore Pte Ltd. 2020.