Study of Liquid Film Forming Apparatus (LFFA) Mechanisms in Terms of Oxygen Transfer and Bubble Hydrodynamic Parameters

  • Marupatch Jamnongwong King Mongkut's University of Technology North Bangkok (KMUTNB)
  • Tawan Charoenpittaya Chulalongkorn University
  • Narapong Hongprasith Chulalongkorn University
  • Tsuyoshi Imai Yamaguchi University
  • Pisut Painmanakul Chulalongkorn University
Keywords: Liquid film forming apparatus, diffused aeration system, volumetric mass transfer coefficient, interfacial area, oxygen transfer efficiency, superficial gas velocity, bubble hydrodynamic.

Abstract

Aeration system is extensively applied in aquaculture and waste water treatment. It provides oxygen for organism living and mixing while consumes colossal amounts of energy for operating. Hence, the improvement of aeration system is not only providing enough oxygen and mixing but also concerning to the energy saving. Liquid film forming apparatus (LFFA) is a simple equipment that itself does not consume any power. It can be installed in existing conventional aeration system without large-scale retrofitting. Laboratory scale experiment were performed in a 190-litre aeration tank. The different types of air diffuser providing different bubble aspects were installed at the bottom of the aeration tank as the conventional diffused aeration systems. The volumetric mass transfer coefficient (kLa) of the aeration systems with LFFA are higher than the conventional systems notably. The mechanism of oxygen transfer in LFFA system can be summarized into 4 patterns: 1) Conventional mechanism, 2) Bubble collection mechanism, 3) Bubble recirculation mechanism and 4) Bubble-Liquid Foam mechanism. Then, the interfacial area (a) is improved comparing with the conventional diffused aeration system. The LFFA system should be operated with small bubble diameter generation (< 3 mm). The kLa can be increase 11 - 37 % depending on generated bubble size. By determining the additional interfacial area (a+), the bubble collection phenomena, as well as, the proper superficial gas velocity (> 0.13 m/s) can be defined and provide a better understanding on oxygen transfer mechanism in LFFA system.

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Author Biographies

Marupatch Jamnongwong

Department of Civil Engineering, Faculty of Engineering, King Mongkut's University of Technology North Bangkok (KMUTNB), Thailand

Tawan Charoenpittaya

Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand

Narapong Hongprasith

Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand

Tsuyoshi Imai

Division of Environmental Science and Engineering, Yamaguchi University, Yamaguchi, Japan

Pisut Painmanakul

Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand

Published In
Vol 20 No 3, Aug 23, 2016
How to Cite
[1]
M. Jamnongwong, T. Charoenpittaya, N. Hongprasith, T. Imai, and P. Painmanakul, “Study of Liquid Film Forming Apparatus (LFFA) Mechanisms in Terms of Oxygen Transfer and Bubble Hydrodynamic Parameters”, Eng. J., vol. 20, no. 3, pp. 77-90, Aug. 2016.

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