Phytoremediation of azo dye acid orange 7 with mycrophyte Typha Latifolia sp. using up- flow constructed wetland

Abstract

Combination of aerobic and anaerobic processes in constructed wetlands can enhance the treatment performance in textile wastewater. This study assessed the treatment of azo dye Acid Orange 7 (AO7) and nutrients using three laboratory-scale up flow constructed wetlands (UFCW) with and without supplementary aeration. Supplementary aeration controlled the size of aerobic and anaerobic zones in the UFCW reactors as evidenced by the oxidation–reduction potential (ORP) and dissolved oxygen (DO) profile of the UFCW. This experiment were conducted with two stages. The AO7 removal efficiency was above 70% and 84% for 1 st and 2 nd stage in all UFCW reactors and most of the color was extensively removed in the aerobic region of the UFCW beds was about 98% and 99%. The intermediates product produced through the breakage of azo bond were significantly reduced in the UFCW reactors with supplementary aeration. The results indicated the applicability of the UFCW reactors to the treatment of azo dyecontaining wastewater. The COD and NH4-N removals in the aerated reactors were about 85% and 94% (1 st stage); 91% and 88% (2 nd stage) , respectively. On the other hand, the COD and NH4-N removals were in the range of 46%-54% and 0%, respectively, in the non-aerated reactors. The supplementary aeration enhanced the removal efficiencies in organic matter, NH4-N and aromatic amines in the UFCW reactors.