Enhanced oxygen mass transfer in air microbubble aeration
Oxygen is the most important biochemical reaction participant in aerobic wastewater treatment processes. Aeration is generally used as an essential process in the majority of wastewater treatment plants to provide dissolved oxygen, accounting for 45％ to 75％ of the plant energy expenditure. Thus, enhanced oxygen transfer in aeration would be of benefit to energy-saving. Submerged bubble aeration is the most popular aeration process used in wastewater treatment plants at present. Bubble size is convinced to be crucial to oxygen transfer and smaller bubbles have been proven to be more favorable for oxygen transfer in bubble aeration. Microbubbles are tiny bubbles with a respective diameter of 10-50 μm, showing great potential to enhance gas-liquid mass transfer due to its small terminal velocity and large specific surface area. The two widely used methods of microbubble generation are based on gas-water circulation and decompression. Recently, a new method was developed for generating monodispersed microbubbles using SPG membranes as the gas-liquid dispersion medium. The goal of this work is to investigate the oxygen gasliquid mass transfer in microbubble aeration using gas-water circulation (GWC) generator and SPG generator, compared to conventional bubble aeration. Gas holdup, gas retention time, overall volumetric oxygen transfer coefficient and oxygen transfer efficiency were determined. The effects of surfactant on microbubble generation and oxygen mass transfer were also investigated.
Chun Liu Lei Zhang Hiroshi Tanaka Xia Huang Yoshiaki Matsuzawa
School of Environmental Science and Engineering, Hebei University of Science and Technology,Shijiazh Technical Development and Engineering Center, IHI Corporation,Shin-Nakahara-cho, Isogo-ku,Yokohama 2 State Key Joint Laboratory of Environment Simulation and Pollution Control, Department of Environmen
国际会议
北京
英文
47-48
2011-11-24（万方平台首次上网日期，不代表论文的发表时间）