Abstract
The energy used for biological process in a wastewater treatment plant depends on aeration equipment and hydraulic parameters in aeration tank. Gas bubbles flow into bioreactor determines an extra turbulence into the mixture. This paper presents the results obtained using the volume of fluid (VOF) mathematical model to determine the velocities generated by bubbles into an upward flow air-water mixture in a column of water. Also, it was identified vertexes center in the ascending air bubbles movement and the number and the diameter of the bubbles were determined. The theoretical results were compared to experimental and theoretical data from the literature and it was found a good correlation.
Highlights
Aeration is a key process in biological wastewater treatment
The uniform distribution of air bubbles and the production of small ones leads to an increase in oxygen mass transfer surface [5], avoiding the clogging of aeration systems, which is a major problem in many types of diffusers
According to the obtained numerical results, it can be stated that from the point of view of the bubble formation, the best solution corresponds to a diameter of d0 = 0.5 mm, because small amounts of spherical air bubbles appear, with large contact area
Summary
Aeration is a key process in biological wastewater treatment. Its role is to supply the oxygen required to fulfill aerobic treatment processes. Aeration ensures the required mixing velocity of the suspended particles, that means medium velocity vm > 0.3 m/s and homogenization of the wastewater-air-sludge mixture. Oxygen transfer is performed at the interface of the two phases, air and water, represented by the surface of the gas bubbles. The uniform distribution of air bubbles and the production of small ones leads to an increase in oxygen mass transfer surface [5], avoiding the clogging of aeration systems, which is a major problem in many types of diffusers. The distribution of dissolved oxygen concentration depends on the tank geometry, dispersion coefficient and gas velocity. These characteristics determine the required gas flow, respectively the efficiency of the aeration system. The air flowrate transferred in water is strongly influenced by the air-water interface
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
