Endurance of Phragmites karka in removing colour and suspended solids from industrial coffee processing effluents in a continuous reed bed system

[Display omitted] •A continuous reed bed system to treat industrial coffee processing effluents is reported.•Colour and total suspended solids (TSS) are reduced by 95 % and 76 %, respectively.•Phragmites karka has the capability to remove colour and TSS.•The rooting system enhances the removal performance of colour and TSS.•Phragmites karka can function as a phytoremediator for industrial coffee processing effluents. Industrial coffee processing effluents are acidic and have high contents of organic matter and dissolved solids. These effluents can subsequently cause several adverse effects to human health and aquatic life if discharged directly. Unfortunately, very limited research attention has been focused on the treatment of coffee wastewater. This study highlights the application of phytoremediation as a sustainable approach to treat coffee processing wastewater using local plants in Malaysia, namely, Phragmites karka. A continuous reed bed system with a hydraulic retention time of 3 d is operated for 34 d to observe the efficiency of phytoremediation treatment in removing the total suspended solids (TSS) and colour concentration of industrial coffee effluents. This system effectively reduces the concentration of TSS and colour by 95 % and 76 %, respectively. It is proved that the rooting system of the plants helps in terms of removal performance for both parameters when compared to the unplanted system.