Treatment potential of Natural wetland Thangal was modelled using SubWet 2.0. Parameters like BOD, nitrate, ammonium and total phosphorus were analysed using the water samples collected at the entry and exit points of the wetland. Model was calibrated and run with these parameters. Vegetation like cattail, duckweed, etc., in the wetland contributed to the removal efficiencies of 16.2%, 18%, 31% and 50% respectively of the above-mentioned parameters. Scenario 1 analysis across the two seasons namely pre-monsoon and monsoon indicate that, there is reduction in the percentage removal of biological oxygen demand (BOD) if there is increase in BOD load in the wastewater. Scenario 2 shows that increase in temperature across two seasons, improved the removal efficiencies of BOD, nitrate and ammonium. Scenario 3 indicates that decrease in the area of Thangal wetland resulted in reduction of all the removal efficiencies in both the seasons. The study concludes that the natural treatment process at Thangal is valued as part of pre-treatment system of wastewater for Pandravedu village.