Title: Treatment potential and phytoextraction capacity of Phragmites australis in the removal of heavy metals from constructed wetlands

Authors: Catherine Rwamba Githuku; Ndambuki Julius Musyoka; Wanjala Ramadhan Salim; Adedayo A. Badejo

Addresses: Department of Civil Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa; Department of Civil Engineering, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya ' Department of Civil Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa ' Department of Civil Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa ' Department of Civil Engineering, Federal University of Agriculture, Abeokuta, P.M.B 2240, Ogun State, Nigeria

Abstract: Industries and mines discharge wastewaters that contain heavy metals that cause toxicity when accumulated beyond permissible limits in the environment and in living organisms. This study investigated the potential use of Phragmites australis in the removal of cadmium, chromium and lead from synthetic wastewaters using constructed wetlands (CWs). CW units made of plastic containers with dimensions of 0.56 m in diameter and 0.70 m deep were set up and planted with Phragmites australis separately then intercropped with other macrophytes. Water, P. australis and soil samples were analysed for heavy metals. The removal efficiencies of metals by P. australis were 96.66 ± 0.76%, 96.22 ± 1.61% and 76.08 ± 3.27% for Cd, Cr and Pb respectively. The metal accumulation results showed that Cd, Cr and Pb accumulated in the P. australis organs in the order roots > stems > leaves. This study recommends further research into application of P. australis in treatment of Cd, Cr and Pb polluted wastewaters.

Keywords: bioaccumulation factor; heavy metal accumulation; kinetic rate; constructed wetlands; Phragmites australis; synthetic wastewater; transfer factor.

DOI: 10.1504/IJEWM.2021.114426

International Journal of Environment and Waste Management, 2021 Vol.27 No.3, pp.310 - 344

Received: 22 Sep 2019
Accepted: 30 Dec 2019
Published online: 21 Apr 2021 *

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