Biological Oxygen-dosed Activated Carbon (BODAC) filters - A bio-based treatment for wastewater reuse and reclamation

Water re-use from municipal wastewater treatment plants (WWTPs) effluent has recently gained more attention. This effluent water usually contains nutrients and trace contaminants, such as organic micro-pollutants (OMPs). Conventional municipal WWTPs are not currently designed to completely remove these OMPs, making additional and reliable treatments might be needed before the water is safely discharged to the environment or is to be re-used. Biological oxygen-dosed activated carbon (BODAC) filters were operated as one of the treatments to further remove nutrient and OMPs from the municipal WWTP effluent in Emmen, the Netherlands, for producing ultrapure water. The long service life, i.e., more than 11 years without carbon replacement or off-site regeneration, of the BODAC filters makes it an attractive bio-based and chemical-free technology for water purification. Additionally, the BODAC filters were demonstrated to be able to protect the reverse osmosis (RO) units from biofouling placed downstream of the filters. In this paper, a holistic approach by analysing BODAC granules and water samples was conducted for one year to understand the mechanisms behind the long-term operation of the BODAC filters in a full- and pilot-scale. Additionally, microbial community analysis was conducted to elucidating the putative microbes for the efficient BODAC filter performance. This study aims to demonstrate BODAC filter performance as a promising bio-based tertiary treatment to further remove foulants and OMPs in WWTP effluent by harnessing the microbiological growth in the filter.