Estimation of rate constants for nutrient transformations

Abstract

Non-point source pollution of surface water is a major impediment to meet water quality objectives. Managing such pollution sources in a sustainable way is a key success factor in maintaining high water quality and to prevent eutrophication. Mathematical models are widely used to simulate ecological and water quality interactions in surface waters. Simulation errors may arise due to uncertainties of the structure, input data and the model parameters. In this study, an attempt has been made to estimate the rate constants for nutrient transformations in Kabini River located in Southern part of Karnataka state in India. The experimental results demonstrated both ammonia and nitrite oxidation. In the river water, DO concentration was 5.2 mg/L. After addition of pollutants it reduced to 3.9 mg/L. EC changed from 370 to 550 µS/cm. pH remained almost the same. At 320C, the rate constants for phosphate, nitrate, nitrite, potassium and ammonia were found to be 0.165, 0.21, 0.077, 0.0777 and 0.078/hr respectively. The results obtained clearly specify that the rate constants are concentration and temperature dependent.