Chromium removal from wastewater using HSF and VF pilot-scale constructed wetlands: Overall performance, and fate and distribution of this element within the wetland environment

• Published in: Chemosphere (Oxford) Vol. 168; pp. 716 - 730
• Main Authors: Papaevangelou, Vassiliki A., Gikas, Georgios D., Tsihrintzis, Vassilios A.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2017
• Subjects: Adsorption; Adsorption capacity; Chromium - analysis; Chromium - metabolism; Chromium removal; Constructed wetlands; Environment; Environmental Restoration and Remediation; Freundlich and Langmuir isotherms; Groundwater - chemistry; Mass balance; Plant uptake; Plants - metabolism; Waste Water - chemistry; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry; Wetlands; Chromium removal; Mass balance; Adsorption capacity; Freundlich and Langmuir isotherms; Constructed wetlands; Plant uptake
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2016.11.002

The current experimental work aimed at the investigation of the overall chromium removal capacity of constructed wetlands (CWs) and the chromium fate-distribution within a wetland environment. For this purpose, the experimental setup included the parallel operation and monitoring of two horizontal subsurface flow (HSF) pilot-scale CWs and two vertical flow (VF) pilot-scale CWs treating Cr-bearing wastewater. Samples were collected from the influent, the effluent, the substrate and the plants. Apart from the continuous experiment, batch experiments (kinetics and isotherm) were conducted in order to investigate the chromium adsorption capacity of the substrate material. According to the findings, HSF-CWs demonstrated higher removal capacities in comparison to VF-CWs, while in both types the planted units indicated better performance compared to the unplanted ones. Analysis in various wetland compartments and annual mass balance calculation highlighted the exceptional contribution of substrate to chromium retention, while Cr accumulation in plant was not so high. Finally, experimental data fitted better to the pseudo-second-order and Langmuir models regarding kinetics and isotherm simulation. [Display omitted] •Experiments in pilot-scale constructed wetlands on chromium removal.•Comparison of horizontal subsurface flow and vertical flow systems.•Effects of loading, plant, material and other parameters.•Adsorption experiments, Freundlich and Langmuir isotherms.