RESPONSES OF ENZYME ACTIVITIES AND MICROBIAL COMMUNITY STRUCTURE IN AN AERATED INTEGRATED VERTICAL-FLOW CONSTRUCTED WETLAND

An aerated integrated vertical-flow constructed wetland (IVCW) was used to treat domestic sewage, and changes in enzyme activities and microbial community structure in the aerated IVCW were investigated. The results showed that aeration increased Eh of all sites, and enlarged the depth of aerobic zone from 33cm to 69cm in the summer and from 17cm to 54cm in the winter. Artificial aeration significantly enhanced dehydrogenase and urease activities, while phosphatase activity was not improved. Four kinds of saturated phospholipid fatty acid (PLFAs) were not determined in aerated IVCW, while artificial aeration obviously increased the relative contents of monounsaturated PLFAs, suggesting that the proportion of aerobic microorganisms significantly increased. More importantly, intermittent aeration had little effect on the relative contents of cyclopropane PLFAs at the bottom layer, indicating that anaerobic denitrification and the proportion of anaerobic microorganisms were not affected. These results could demonstrate why the aerated IVCW had a better treatment performance.