Textile wastewater treatment using horizontal flow constructed wetland and effect of length of flow in operation efficiency

Textile wastewater treatment is a challenging process due to its high-intensity color and high COD value. In this study, the effect of design parameters of constructed wetlands in the treatment of synthetic textile dyeing bath effluent using horizontal flow constructed wetlands was explored. The effect of length of flow through the wetlands and hydraulic retention time in pollutant removal were analyzed. Two wetland reactors, one baffled, and the other non-baffled reactors were operated with varying lengths of flow and HRT (3 days to 7 days). It was observed that the maximum color (72 ± 2%) and COD removal (85 ± 3%) occurred in the baffled reactor at a dye loading rate of 1.15 g/m 2 d and COD loading rate of 10.3 g/m 2 d. The pH change and sulfate removal rates (34 ± 2%) at a sulfate loading rate of 2.8 g/m 2 d were similar in both reactors. Overall, the length of flow affected slightly the performance of wetland reactors for color and COD removal. The study suggests that there exists a need for the development of proper design parameters for the effective use of constructed wetlands in the treatment of wastewater. • Constructed wetland was explored for the treatment of textile wastewater. • The effect of length of flow on treatment was studied. • Treatment efficiency obtained with three different HRTs was studied. • Significant dominance of extra length in color and COD removal.