Investigation of pilot-scale constructed wetlands treating simulated pre-treated tannery wastewater under tropical climate.
Tannery wastewater is characterized by high and variable concentrations of diverse pollutants, which makes it difficult and costly to treat. In the search for sustainable treatment options for tannery effluents, two pilot-scale horizontal subsurface flow (HSF) constructed wetlands (CW) were built and operated for the treatment of synthetic water of quality similar to that of pre-treated tannery effluents. Five different loading phases were examined with gradual increase of inflow COD, NH4+-N and Cr loads until reaching and exceeding the typical composition of a tannery effluent. High COD and NH4+-N removals were observed (82 and 96%, respectively), and almost complete Cr removal in the outflow, which met the Venezuela national standards for environmental discharge. Plant uptake was measured, but microbial processes appear to be the main ammonium transformation/removal mechanism. Nitrogen, chlorophyll and Cr in the plant aerial parts and roots indicated the capacity of Phragmites sp. to grow and survive even under high loads. The measured heterotrophic bacteria in the substrate and rhizomes indicated the biofilm development and the oxidation of organic matter and nitrogen. Water losses via evapotraspiration were also measured and reached 14%. Overall, the tested CW design proved to be a sustainable and feasible alternative for the treatment of tannery wastewater in tropical climates.
['Ramírez|Susana|S|', 'Torrealba|Graciela|G|', 'Lameda-Cuicas|Eudimar|E|', 'Molina-Quintero|Luisa|L|', 'Stefanakis|Alexandros I|AI|', 'Pire-Sierra|Maria Carolina|MC|']
D001419:Bacteria D018441:Biofilms D009584:Nitrogen D010865:Pilot Projects D010944:Plants D006109:Poaceae D014329:Tropical Climate D014687:Venezuela D014865:Waste Disposal, Fluid D062065:Waste Water D018508:Water Purification D053833:Wetlands
Constructed wetlands Tannery wastewater Phragmites sp. Heterotrophic bacteria Chromium Natural treatment systems