title: The effect of aeration and recirculation on a sand-based hybrid constructed wetland treating low-strength domestic wastewater.
abstract: The Duplex-constructed wetland (CW) is a hybrid system composed of a vertical flow (VF) CW on top of a horizontal flow filter (HFF). Each compartment is designed to play a different role: aerobic treatment in the VF CW due to intermittent feeding and anoxic treatment in the HFF due to saturated conditions. Three Duplex-CWs were used in this study: Control, Aerated and Recirculating. The role of each compartment was tested for pollutant removal and micro-invertebrate abundance. In all systems, the VF CW removed mainly organic matter, solids and NH4(+)-N. Pathogens were removed in both compartments. Likewise, total nitrogen removal occurred in both compartments, only the Recirculating HFF was not able to denitrify the nitrogen due to the slightly more oxic conditions as compared to the other systems. All systems met discharge guidelines for organic matter, but only the Control and Aerated systems met those for total nitrogen. At the applied loading rates, the pollutant removal was not significantly enhanced by the use of aeration and recirculation. Therefore, operation as in the Control system, without aeration or recirculation, is recommended for the tested Duplex-CWs. If artificial aeration will be used in CWs, the support material should be carefully selected to allow a proper air distribution.
authors.affiliation: a UNESCO-IHE Institute for Water Education , Delft , The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Zapater-Pereyra
authors.affiliation: a UNESCO-IHE Institute for Water Education , Delft , The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Kyomukama
authors.affiliation: a UNESCO-IHE Institute for Water Education , Delft , The Netherlands.
authors.forename: V
authors.initials: V
authors.lastname: Namakula
authors.affiliation: a UNESCO-IHE Institute for Water Education , Delft , The Netherlands.
authors.forename: J J A
authors.initials: JJ
authors.lastname: van Bruggen
authors.affiliation: a UNESCO-IHE Institute for Water Education , Delft , The Netherlands.
authors.forename: P N L
authors.initials: PN
authors.lastname: Lens
mesh_terms: D000388:Air; D001673:Biodegradation, Environmental; D004867:Equipment Design; D012822:Silicon Dioxide; D014865:Waste Disposal, Fluid / Q000295:instrumentation*; D062065:Wastewater / Q000737:chemistry*; D053833:Wetlands
chemical_list: D012822:Silicon Dioxide; D062065:Wastewater
keywords: Aeration; hybrid constructed wetland; low-strength domestic wastewater; nitrogen; recirculation