A number of volatile organic compounds (VOCs) are found in the wastewater and some of these VOCs are very harmful to human health as well as environment. Although there are several methods which are being used for the removal of VOCs, air stripping process is the low energy usage, low preventive and maintenance cost and high efficiency process which can stripe VOCs from wastewater. The present study consists of aeration system for the removal of VOCs. Aeration of VOC is based on the mass transfer rate of VOCs from the liquid to gaseous phase. Principle of air stripping involves the mass transfer of volatile organic contaminant from water to air. The system can be easily upgraded to strip greater amount of VOCs with relatively small increase in capital cost. Aeration tanks strip volatile compounds by bubbling air into tank through which contaminated water flows. The present study shows aeration of a VOC by using advanced designed gas dispersing radial impeller that is, Rushton, CD-6 and BT-6 and the factors which affect the design of an aeration tank baffles and the impeller used for best possible result. This study also shows the removal of VOCs at different height of submergence. It also shows the effect of air supply on the removal of VOCs at different operating condition. A comparison of the result from experiment shows the emission rate of VOCs during aeration and is a function of mass transfer coefficient of air; it increases with increase of submergence of height, by supply of air, and increase in impeller speed. Best aeration result can be obtained at the 2/3rd height of the submergence of the total depth of water for impeller used. The study also shows that the gas dispersion BT-6 impeller has larger removal efficiency (up to 96%, with air supply at 4 h run) compare to Rushton and CD-6 impeller.
Key words: Volatile organic compounds (VOCs), aeration, mass transfer coefficient, stripping, gas dispersion impellers, Rushton, CD-6, BT-6, gas liquid mass transfer.
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