Performance Evaluation of a Constructed Wetland System for Treating Industrial and Domestic Wastewater in Southern Punjab, Pakistan

Abstract

Water scarcity is an escalating global issue driven by rapid population growth, industrialization, and poor water management practices. According to the World Water Assessment Program, two thirds of the global population may face severe water shortages by 2025, with nearly half affected by 2030. In Pakistan, per capita water availability has declined from 5000 m³ year^-1 in 1951 to approximately 1100 m³ year^-1 placing the country at the risk of critical water stress. Constructed wetlands (CWs) have gained recognition as cost-effective, nature-based systems for treating wastewater, especially in regions struggling with pollution and freshwater scarcity. This study was conducted at C-block of MNS-University of Agriculture, Multan, where a surface flow constructed wetland system was established to treat wastewater from the Wali Muhammad Distributary- a canal contaminated with untreated domestic and industrial effluents. The wetland consisted of sequentially arranged vegetated ponds designed for natural filtration. Over three weeks, wastewater samples were collected weekly and analyzed for key physico-chemical parameters. Statistical analysis was conducted using R software and significance was assessed using t-test at p<0.05. The system achieved notable reductions across various parameters such as pH (16%), EC (93.30%), carbonate (82%), bicarbonate (66%), total dissolved solids (TDS) 75%, total solid (TS) 84.43%, total suspended solid (TSS) 75%, biological oxygen demand (BOD) 84.23%, chemical oxygen demand (COD) 39%, potassium (K) 53%, sodium (Na) 75%, and calcium (Ca) 68%. These findings demonstrate high pollutant removal efficiency for sustainable treatment.