Cultivation And Hydrodynamics Of The Aerobic Granular Sludge

Aerobic granular sludge is a novel and promised biotechnology for handling wastewater. Aerobic granular sludge feeding with synthetic wastewater was successfully cultivated in a sequencing batch reactor. The aerobic granular sludge has several advantages, such as a denser and stronger microbial structure, good settleability, high biomass retention, ability to withstand high organic loading rate and remove nitrogen and phosphorus simultaneously. The calcium plays an important role in the cultivation of the aerobic granular sludge and it exists in the center of the granule where there has no microbe in the form of calcium carbonate. The existence of the calcium can improve the stability and the strength of the aerobic granule. The shear strength and the compressive strength of the aerobic granule sludge were studied. The result shows that it's advantageous to add proper quantity of calcium into the influent to improve the stability of the granule sludge. The excellent hydrodynamic conditions of the sequencing batch reactor play an important role in the formation and structure of the aerobic granular sludge. A three-dimensional transient model was developed to simulate the local hydrodynamics of a gas-liquid-solid three-phase aerobic granular sludge sequencing batch reactor using the computational fluid dynamic model. Modeling calculations have been carried out using the computational fluid dynamic code FLUENT. The result shows that it's proper to use the Euler-Euler model to simulate the multi-phase fluid in the sequencing batch reactor. The simulation results show great consistent with the experiment observes and the literature reports.