Optimization of performance assessment and design characteristics in constructed wetlands for the removal of organic matter.
Some of the most used constructed wetland (CW) configurations [conventional and modified free-water (FW) flow, surface flow, conventional horizontal subsurface flow (SSF) and soilless systems with floating macrophytes (FM)] were assessed in order to compare their efficiencies for the removal of organic pollutants [COD, filtered COD (FCOD), BOD and total suspended solids (TSS)] from urban sewage under the same climatic and wastewater conditions. The removal performance was calculated using three approaches: effluent concentrations, areal removed loads and mass removal. Results were very different depending on the approach, which indicates that the way to present CW efficiency should be considered carefully. All CW-configurations obtained BOD effluent concentrations below 25 mg L(-1) in summer, with a FW-CW with effluent leaving through the bottom of the tank being the only one maintaining low BOD effluent concentrations even in winter and under high organic loading conditions. In this kind of CW, the presence of plants favoured pollutant removal. SSF-CWs were the most efficient for the removal of COD. FM systems can be as efficient as some gravel bed CWs. Typhaangustifolia worked better than Phragmitesaustralis, at least when the systems were at the beginning of their operation period.
Hijosa-Valsero
María
M
Facultad de Ciencias Biológicas y Ambientales, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain. mhijv@unileon.es
Sidrach-Cardona
Ricardo
R
Martín-Villacorta
Javier
J
Bécares
Eloy
E
D001673:Biodegradation, Environmental; D004779:Environment Design; D052918:Environmental Restoration and Remediation / Q000379:methods*; D006109:Poaceae / Q000254:growth & development; D032401:Typhaceae / Q000254:growth & development; D014865:Waste Disposal, Fluid; D014873:Water Pollutants / Q000032:analysis*; D014876:Water Pollution / Q000706:statistics & numerical data; D053833:Wetlands
D014873:Water Pollutants