Discharge of contaminated water through the storm water drains is a major reason for the deterioration of the water quality of Lakes situated in urban areas. Therefore to prevent the entry of silt and contaminants into the lake and to maintain the water quality of lakes, we are proposing a Constructed wetland treatment system at one of the major inlet of Selaiyur lake so that contaminated urban water can be treated to the desired quality and then let into the lake.
The constructed wetland treatment system operates by channelizing the runoff during normal flows to a treatment setup consisting of a sedimentation tank for removing suspended & floating particles, followed by a horizontal flow constructed wetland (HFCW) which is a shallow basin filled with a inert substrate with semi aquatic plants tolerant to saturated conditions. The artificial wetland can be constructed with an impermeable layer on the bottom and the inflow is uniformly distributed in the HFCW so that the inflow is treated well utilizing an area of 30 m x 30 m adjacent to the lake area.
As the water passes through the growing medium the roots of the plants absorb the dissolved phosphorus and nitrates which is used by the plants to grow. As a result the inflow water is treated and only clarified water is discharged into the lake. Moreover the roots of the wetland plants release oxygen which helps in improving the dissolved oxygen concentration of the water.
Constructed wetlands have a proven track record of Pollutant Removals.
