A constructed wetland model for synthetic reactive dye wastewater treatment by narrow-leaved cattails (Typha angustifolia Linn.)

摘要

Textile wastewater is contaminated by reactive dye causing unattractive levels of wastewaterncolor, high pH and high salt content when discharged into public water systems. Decolorizationnof textile wastewater by plant, phytoremediation, is an alternative, sustainable method which isnsuitable for long term operation. Narrow-leaved cattails are one species of wetland plant withnefficiency for decolorizing and remediating textile wastewater. In addition, chemical oxygenndemand (COD) can be lowered and dye residue can be removed. The plant also showed a goodnsalt tolerance even after being exposed to a salt solution for 15 days. The narrow-leaved cattailsnwere set up in a constructed wetland model with a vertical flow system operating from bottomnto top for synthetic reactive dye wastewater (SRDW) removal. Narrow-leaved cattails couldnachieve the removal of SRDW at approximately 0.8 gSRDWm22 day21. Decolorization of SRDW bynthis plant was approximately 60%. The advantage of this method is that it is suitable for textilenwastewater management and improvement of wetland. These plants could lower COD, removendye, sodium and total dissolved solids (TDS) whereas other biological and chemical methodsncould not remove TDS and dye in the same time. These results suggested that the spongy cellnstructure of this plant has the ability to absorb large amounts of water and nutrients.nPhysico-chemical analysis revealed increasing amounts of sulfur, silicon, iron and calcium in thenplant leafs and roots after exposure to wastewater. Proteins or amide groups in the plant mightnhelp in textile dye removal. Regarding decolorization, this plant accumulates dye in thenintercellular space and still grows in this SRDW condition. Hence, it can be noted here thatnnarrow-leaved cattails are efficient for textile dye wastewater treatment.