A novel algae-assisted sequencing batch and intermittent air-lift bioreactor (A-SBIAB) using polyester filament-based carriers for piggery wastewater treatment.

Algae-assisted biological wastewater treatment technology has been widely applied in wastewater treatment due to its low cost and great removal performance. However, the stabilization and sustainability of the alga-bacteria symbiosis system still need to be developed. In this work, an algae-assisted sequencing batch and intermittent air-lift bioreactor (A-SBIAB) system was constructed for removing the nutrients from the piggery wastewater. A strengthened algae-bacterial symbiosis system was also achieved with the aid of a suspended bio-carrier composed of polyester filament fixed on concentric plastic rings, which provided enhanced surface area and illumination access for microbial attachment. The removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were up to 92.0%, 81.7% and 89.3%, respectively, at the optimum parameters (Chl-a concentration of 1000 mg/m³, light intensity of 6000 lx and lighting time 10 h). The Campylobacteria (72.05%), Desulfuromonadia (11.16%), Spirochaetia (3.10%) and Bacteroidia (1.73%) as the dominant bacterial communities would be responsible for the nitrate ammonification, nitrogen fixation, nitrate reduction and organics degradation, respectively. Meanwhile, Chlorophyceae (98.21%) became the overwhelming algal community, playing a positive effect on the nutrients removal.