Azo dyes are commonly generated as effluent pollutants by dye using industries, causing contamination of surface and ground water. Various strategies are employed to treat such wastewater; however, a multi-faceted treatment strategy could be more effective for complete removal of azo dyes from industrial effluent than any single treatment. In the present study, rice husk material was used as a substratum in two constructed wetlands (CWs) and augmented with microorganisms in the presence of wetland plants to effectively treat dye-polluted water. To evaluate the efficiency of each process the study was divided into three levels, i.e., adsorption of dye onto the substratum, phytoremediation within the CW and then bioremediation along with the previous two processes in the augmented CW. The adsorption process was helpful in removing 50% dye in presence of rice husk while 80% in presence of rice husk biocahr. Augmentation of microorganisms in CW systems has improved dye removal efficiency to 90%. Similarly presence of microorganisms enhanced removal of total nitrogen (68% 0 and Total phosphorus (75%). A significant improvement in plant growth was also observed by measuring plant height, number of leaves and leave area. These findings suggest the use of agricultural waste as part of a CW substratum can provide enhanced removal of textile dyes.

Biosorption is a widely used technology for wastewater treatment, especially for removal of pollutants that are not easily biodegradable. Plant-based agricultural wastes have gained attention as effective biosorbents due to their low cost, potential for waste reuse, and their adsorption characteristics. An extensive list has been compiled of plant materials (e.g., different parts of plants) used for biosorption of industrial dyes and for enzyme-assisted decolorization. The purpose of this review was to summarize the information available on (i) adsorption of industrial dyes on plant-based biosorbents, (ii) factors affecting adsorption processes, (iii) isothermal and kinetic modeling, (iv) thermodynamics, and (v) fungal enzymatic decolorization of dyes on lignocellulosic biomasses in biosorption studies. A wide variety of plant wastes, mainly agricultural residues, can be used for biosorption, and fungal enzymes can accelerate the decolorization process. These low-cost biosorbents have showed quantifiable capability in dye adsorption and biodegradation. Accordingly, there is a need to develop commercial-scale biosorption technology for aqueous pollutant removal and environmental protection.