Abstract:
Discharge of untreated wastewater is responsible for water quality deterioration. It is essential to treat wastewater in order to reduce the environmental risks. The present study aims to present an application of a combined system of Constructed Wetlands (CW) and Land FILTER (Filtration and Irrigated cropping for Land Treatment and Effluent Reuse) technique (developed at CSIRO, Australia and tested successfully both in Australia and China) for the treatment of domestic wastewater for the first time in Pakistan. The wastewater being generated from offices, student hostels and staff residential colony located at National University of Sciences and Technology (NUST), Islamabad Campus is being directed towards a Sedimentation Tank and after settling of solid waste & scum is discharged into a Constructed Wetland divided into eight compartments. In the last wetland compartment, aeration (run on solar energy) is also carried out. The effluent from the Constructed Wetland discharges, through a distribution system, to FILTER plot for further quality improvement. The effluent from the FILTER is then collected through the tile drainage system and its quality compared against the inflow wastewater. The behavior of various water quality parameters was studied and the relationship between climatic, hydrologic and water quality parameters was developed. As the treated wastewater satisfactorily meets the Pakistan National Environmental Quality Standards (NEQS), thus it may be used for horticulture & replenishing underlying groundwater aquifer. The results from a Six month experimental period showed the removal efficiencies of parameters as Total Suspended Solids (TSS) (65%), Chemical Oxygen Demand (COD) (92%), Biological Oxygen Demand (BOD) (88%), Total Phosphates (TP) (58%), Total Coliforms (TC's) (92%) and Fecal Coliforms (FC's) (94%). This study is expected to add better understanding of FILTER and constructed wetland systems, and establish an effective framework for future applications.
