Abstract

Water quality of many lakes in Chennai is deteriorating due to fast urbanization and industrialization. Urban wastewater contains both organic and inorganic nutrients and discharge of untreated water increases nitrogen and phosphorous content in water bodies leading to eutrophication problem. This study firstly aims to assess physicochemical characteristics of Velachery Lake water for effective management of the lake. Water samples were collected during the post monsoon season. The sampling and analytical methodologies were followed for the estimation of selected parameters as per ‘Standard methods of water and wastewater analysis’ (APHA 2005). This study also investigates the growth of micro algae Chlorella vulgaris in Velachery Lake water and also the reduction of pollution at the end of growth phase. The biomass density, biomass productivity and the lipid content were estimated as 0.722 ± .028 g/l, 0.0589g/l/d, 21 ± .06%. The results emphasized that polluted lake water as a cost-effective growth medium for higher biomass and lipid production accompanied with the nutrient removal efficiency of micro algae to reduce eutrophication. The removal efficiencies were assessed as 91.63 ± .054% for TN, 96.31 ± .022 for TP, 67.93 ± 2.78% for COD, 80.95 ± 2.01% for BOD. The TDS reduction was estimated as 32 ± 1.28%. The results of this study demonstrated that even the lake water with less concentration of nutrients is a suitable growth medium for microalgae, since C. vulgaris could adapt well with the environmental stress factors.

Keywords: Chlorella vulgaris; Nutrient Removal; Biomass; Biomass Productivity; Lipid; Eutrophication