Comprehensive Assessment of Water Quality and Pollution in Mallathahalli Lake, Bangalore

IJEP 46(6): 561-570 : Vol. 46 Issue 6 (June 2026)

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Kodagahally Ramegowda Ravi Kumar1,2,3* and Spoorthi1

1. Robust Materials Technologies Pvt. Ltd. (DSIR Approved Research and Development Centre), Nagarabhavi, Bengaluru – 560 072, Karnataka, India
2. V.R. Institute of Chemical, Biological and Information Science, Bharat Nagar, Bengaluru – 560 091, Karnataka, India
3. Simposys Healthcare LLP, Naagarabhavi, Bengaluru – 560 072, Karnataka, India

Abstract

The present study evaluates the physico-chemical and microbiological characteristics of water and sludge in Mallathahalli lake, Bengaluru, India, with an emphasis on pollution status and treatment efficiency. Lake water exhibited elevated biochemical oxygen demand (6.25±1.35 mg/L), low dissolved oxygen (3.13±1.17 mg/L) and high nutrient concentrations, particularly phosphates (3.04±0.87 mg/L), indicating severe eutrophication. Extremely high total coliform counts (upto 4.3×105 MPN/100 mL) and the presence of Escherichia coli confirm significant fecal contamination. Effluent analysis revealed substantial improvement after sewage treatment, with marked reductions in chemical oxygen demand (368 to 8 mg/L) and suspended solids; however, nitrate and phosphate levels remained above permissible limits and microbial contamination persisted. Borewell water showed acceptable overall physico-chemical quality, though hardness and alkalinity were elevated and 44% of samples were microbiologically unsafe. Sludge analysis indicated that heavy metal concentrations were within permissible limits, with iron as dominant metal. The findings highlight that Mallathahalli lake is in a hypereutrophic and microbiologically contaminated state, primarily due to untreated or partially treated sewage inflow. Immediate interventions, including improved wastewater treatment and nutrient load management, are necessary to restore ecological health and ensure safe water use.

Keywords

Mallathahalli lake, Domestic sewage, Sludge quality, Water quality, Physico-chemical, Biological oxygen demand

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