An innovative jet loop-airlift bioreactor for simultaneous removal of carbon and nitrogen from soft drink industrial wastewater: Process performance and kinetic evaluation

Creating different redox conditions in different regions can be effective for nutrient removal in a single bioreactor. Jet loop-airlift bioreactors are presented as an innovative system that can provide regions with different oxidation-reduction potentials (ORP). In the present study, the performance of a novel jet loop-airlift bioreactor for the simultaneous removal of nutrients from soft drink wastewater (SDW) (COD:N:P of 100:16:1) was investigated. The anoxic and aerobic zones with settling tank could successfully be integrated in a compact high rate bioreactor under continuous aeration and feeding. Two independent variables, hydraulic retention time (HRT) (6-14 h) and air flow rate (2.5-4.5 l/min), were chosen at three levels for modeling, optimization, and trend analysis. According to experimental data, optimum conditions were achieved at HRT of 11 h and air flow rate of 4 l/min with TCOD and TN removal of 98% and 83.6%, respectively. Also, kinetic analysis of the soft drink wastewater treatment process in the jet loop-airlift bioreactor was performed and Y, K-d, K-s, K and mu(max) were found to be 0.2425 gVSS/gCOD, 0.038 d(-1), 0.00786 g/l, 0.6321 d(-1) and 0.165 d(-1), respectively. In conclusion, the jet loop-airlift system can be described as an effective low-cost bioreactor for treating wastewater with high carbon and nitrogen. (c) 2020 Elsevier B.V. All rights reserved.