Experimental and CFD simulation study on anaerobic digestion using dextran pharmaceutical wastewater based on cyclic fluidization hydraulic mixing

Pharmaceutical wastewater is a kind of high‐hazardous waste. To realize non‐waste production, experiment and computational fluid dynamics (CFD) simulation were performed to reveal the hydraulic mechanism of mixing modes. Three digesters, numbered 0# (no‐port), 1# (one‐port), and 4# (four‐port), were conducted by dextran pharmaceutical wastewater. Digester 0# is the control group without mixing. Mixing mode of bottom inlet and high‐position outlet is employed to 1# and 4#, the outlets of 1# and 4# are centralized outlet with only one port and distributed outlets with four ports, respectively. Experiment result shows the daily biogas production of 1# and 4# are 45% and 58% higher than 0#, and the pollutants removal rate increased 20% and 24%, respectively. CFD simulation shows the second phase (dextran wastewater) of 4# failing to form a complete hydraulic path like the first phase (water), which explain the mixing modes can greatly improve the biogas yield, but the four‐port mode has a weaker advantage than the one‐port.