Abstract:
Diffused aeration system is extensively use in current application, such as aquaculture and wastewater treatment, so improvement of instrument for increasing performance of the system is a striking topic. Liquid Film Forming Apparatus (LFFA) is a simple equipment installed in diffused aeration system. The volumetric mass transfer coefficient (kLa) of the system can be significantly increased. Laboratory scale experiment were performed in 190 and 330 litre aeration tank, and pilot scale in 90,000 litre pond. Main mechanisms of LFFA are the development of turbulence of liquid and retention time of bubble: the interfacial area can be thus enhanced when compares with that obtained with the normal diffused air aeration. The kLa coefficients and oxygen transfer efficiencies obtained with fine bubble diffuser were higher than those obtained with coarse bubble diffuser. The proper superficial gas velocity for this system is more than 2.2 cm/s for cross section area of LFFA head; can be increased 11 - 37% of kLa depending on bubble size. From the results of actual pond, the 4-D* with partitions was proposed as the suitable pattern for the LFFA installation. The advantage could be obtained from highly energy performance with 1.20 kg/kW-h of Standard Aeration Efficiency (SAE).