Treatment of Grey Water Using Horizontal Flow Constructed Wetland

Abstract

The aim of this work was to study the pollutant removal efficiencies of two lab-scale horizontal flow constructed wetland systems treating real greywater with Canna Indica as a wetland plant. Both the wetland systems had an identical configuration. Horizontal Flow System 1 (HF1) acted as a control unit, without wetland plants whereas Horizontal Flow System 2 (HF2) acted as a constructed wetland, planted with Canna Indica. To understand the removal efficiencies of various pollutants in the greywater these systems were operated simultaneously under batch mode of flow for different Hydraulic Retention Time (HRT’s) of 10, 6, and 4 days. Removal of TSS (89-95%), BOD (70-85 %), COD (72-80%), NH3 –N (32-43%), TP (45-52%) and Surfactant (50-56%) were obtained in the HF1 control wetland system and Removal of TSS (89-92%), BOD (75-91%), COD (80-95 %),NH3 –N (48-59%),TP (49-56%) and Surfactant (80-83%) were obtained in the HF2 constructed wetland system . These results indicates the percentage of TSS,BOD, COD, NH3 –N and TP removal values are in close proximity to each other in both planted and control wetland systems. However the removal efficiency of pollutants in constructed wetland system was high, especially in the removal of surfactant when compared to the control system. Hence the macrophytes play a major role in the removal of pollutants .Similarly as the HRT increases the treatment efficiency of the constructed wetland also increased.