Hu, Y.S.Y.S.HuZhao, Y.Q.Y.Q.ZhaoZhao, X.H.X.H.ZhaoKumar, J.L.G.J.L.G.Kumar2013-01-142013-01-142012 Elsev2012-05Bioresource Technologyhttp://hdl.handle.net/10197/4021Step-feeding strategies have been extensively studied and comprehensively analyzed in this study for a four-stage alum sludge-based tidal flow constructed wetlands (AlS-TFCWs) system. Enhanced total nitrogen removal of 83% is achieved under high nitrogen loading rate of 19.1 g N/m2 d. The key issues towards the success of a significant nitrogen removal in step-feeding TFCWs are the bed resting time (which provides better aeration for nitrification) and up flow stage/delayed input of side stream(s) (which ensure favorable environment for better denitrification). Simultaneous nitrification and denitrification (SND) was found effective in the 1st stage of the system and SND via nitrite is the main nitrogen conversion mechanism. The optimal influent distribution fraction for step-feeding purpose can be estimated from a theoretical basis, which is a function of the influent BCOD/TKN ratio. Therefore the influent distribution fraction should be adjusted according to the variety of influent characteristics, rather than a fixed value.enThis is the author’s version of a work that was accepted for publication in Bioresource Technology resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Bioresource Technology (Volume 111, May 2012, Pages 27–35) DOI:# 10.1016/j.biortech.2012.01.165 Elsevier Ltd.Alum sludgePartial nitrificationSimultaneous nitrification and denitrification (SND)Step-feedingTidal flow constructed wetlandsJournal Article111May 2012273510.1016/j.biortech.2012.01.165https://creativecommons.org/licenses/by-nc-nd/3.0/ie/