Analysis of Flotation Tank in terms of Flow Pattern and Particle Separation from Liquid Phase
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Abstract
Flow patterns of fluid in reactor have an effect on particle separation efficiency by dissolved air flotation process. First part of this study examined the hydrodynamic parameters of the flotation tank including Liquid flow rate (QL), Pressurized water flow rate (QPW), Air flow rate (Qg,1 and Qg,2), and type of air diffuser (D1) by the residence time distribution function theory. The flow patterns were experimentally examined throughout the reactor by pulse tracer input method which Sodium chloride (NaCl) was used as tracer. Dispersion model and Design of Experiments (DOE) were applied to analyze result in term of dispersion number (d; D/uL). The result showed that flow patterns of the flotation tank are Plug flow reactor with large extents of dispersion. The highest D/uL value is obtained at 0 lpm, 7.5 lpm, and 2.5 lpm of QPW, Qg,1, and Qg,2 respectively. Second part, Treatment efficiency of synthetic wastewater containing microalgae and turbid particle was investigated. The optimum operating conditions are 0.15-0.32 mg air/ mg solid of Air to solids ratio (A/S) combined with Alum addition and 0.107-0.112 of D/uL of the flotation tank that the particle separation efficiency is higher than 72%
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