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Removal of Volatile Organic Contaminants via Low Profile Aeration Technology (WaterRF Report 4439)
Citation:
Ahmed, Z., D. Hand, AND D. Perram. Removal of Volatile Organic Contaminants via Low Profile Aeration Technology (WaterRF Report 4439). Water Research Foundation, Denver, CO, 2014.
Impact/Purpose:
Based on the findings of this project, it is recommended that drinking water treatment utilities consider low profile aeration systems to remove VOCs to sub μg/L ranges. Low profile air strippers are recommended not only because of their convenience, ease of use, and assembly, but also because of their high efficiency under a wide range of conditions. Performance graphs give insight on the high removal efficiencies under various air-to-water ratios (53-652) and various temperatures (4-20°C). Designers, engineers, and utilities should consult these graphs if the removal of these VOCs is considered. The results of this study showed that sub ug/L concentrations were achieved even at air- to-water ratios as low as 53. This suggests that low profile air stripping could be a cost effective technology. Further research is needed in the form of a detailed performance and cost effectiveness study, which would compare low profile air stripping to other conventional treatment technologies.
Description:
The U.S. Environmental Protection Agency (EPA) is considering a change in the way contaminants are regulated as a part of their new drinking water strategy (DWS). The strategy will regulate contaminants as groups rather than individually. The first group consists of 16 VOCs, and little information is available about the effectiveness of aeration technologies, such as low profile aeration, in the removal of most of the VOCs in this group to sub ug/L concentrations. Multistage low profile air stripping is an alternative technology to the conventional packed tower aeration systems for the removal of VOCs, mainly because it requires less height and is less susceptible to inorganic fouling. This technology, however, has limitations as to flow rates that can be accommodated. The objective of this project is to determine the effectiveness of tray aeration technology for removing 13 focus carcinogenic volatile organic compounds (VOCs) to the sub μg/L concentration range. The VOCs’ removal efficiencies were studied by collecting operational data from pilot plant operations, under various air-to-water ratios (53 – 652), three different temperatures (4, 12, and 20°C), and 1 to 6 trays in series. Thirteen 13 VOCs were studied: benzene, carbon tetrachloride, 1,2-dichloroethane, dichloromethane, 1,2-dichloropropane, tetrachloroethylene (PCE), trichloroethylene (TCE), vinyl chloride, 1,3-butadiene, 1,1-dichloroethane, 1,1,2,2- tetrachloroethane, 1,1,1,2-tetrachloroethane, and 1,2,3-trichloropropane.
