72-Phytoremediation for treatment of Eutrophic Lake

Abstract

Bangalore city does not have any perennial river .It is dependent on river Cauvery which is about 140 km away to provide water to its residents Pumping water is an expensive business as the population of Bangalore increases the demand for water to increases .My present study is on heavily polluted lake the BELLANDUR LAKE and Phytoremediation for treatment of eutrophic lake. The lake is located at a latitude 12° - 45' -0"and longitude 77° - 40' - 0". The total catchment area of the lake is 110.94 Sq miles. The annual rainfall of the catchment area is 32 inches. It has a submerged area of 915.00 acres. The tank remains full throughout the year since it receives sewage water of about 100 MLD from Bangalore city in addition to its own supply of water of rainfall from its own catchment's area.

Study has shown that lake water is highly eutrophicated has DO less than 1.6mg/L, high phosphate 10.4mg/L to9.2mg/L,. Surprisingly nitrate levels are below the permissible limit( 7.6 mg/L is the maximum). Eutrophication of Ientic water bodies is a problem of increasing environmental and ecological concerns is particularly serious when there is no perennial river. Phytoremediation for treatment of eutrophic lake was taken up using Vetiver and Cana which were grown in small basins and allowed to float using bamboo for the removal of N and P containing eutrophic lake water in the basin for a week .The total phosphorous and nitrate removed were recorded .The proposed research taken is to transform the natural lake into a waste water treatment plant using Phytoremediation .This technique plays an important role since the phyto Biofilm (Vetiver and Cana )introduced near the inlet point where the incompletely treated sewage water is discharged by treating the polluted water and giving aesthetic beauty to the otherwise eutrophic lake.