Upgrading two-stage membrane bioreactor by bioaugmentation of Pseudomonas putida entrapment in PVA/SA gel beads in treatment of ciprofloxacin

The laboratory scale of the two-stage membrane bioreactor (2S-MBR) was investigated to find the optimal hydraulic retention times (HRT) in treatment of selected 10 antibiotics in real hospital wastewater. It showed that elimination of the antibiotics varied, depending upon antibiotic types and HRT. High biodegradation attributed to amoxicillin and clarithromycin. Fluoroquinolones/tetracycline adsorbed highly on anoxic (ANX) sludge, but tended to be biodegraded in the aerobic tank. Sulfamethoxazole/trimethoprim were mainly accumulated in the ANX/aerobic sludge. In order to increase biodegradation, 2S-MBR was upgraded to a three-stage MBR (3S-MBR) using the polyvinyl alcohol and sodium alginate (PVA/SA) beads of Pseudomonas putida (TISTR1522) in an entrapped cells reactor (ECR) as a pretreatment unit. Ciprofloxacin (CIP) in a synthetic wastewater was a refractory antibiotic for this feature investigation. It showed improvement of CIP degradation reached to 90% in 3S-MBR as compared to 58% of 2S-MBR. As a result, 24 CIP-transformed products (TPs) were detected. Additionally, 3S-MBR showed better efficacy of nitrogen removals. The SEM and FISH techniques revealed bacterial consortium in the system showing that the beads were well supported P. putida growth as well as synchronizing volume available for other bacteria. This feature makes P. putida being a potential microorganism for CIP biodegradation via bioaugmentation in 3S-MBR.