Deoxygenation and Reaeration Coupled hybridMixing cells Based Pollutant Transport Model to Assess water Quality Status of a River

Prediction of spatial and temporal variation of water quality is vital for managing pollutants disposal into the rivers. Depletion of dissolved oxygen (DO) takes place due to the consumption of oxygen by microbes to digest bio-degradable pollutants which enter a water course. Reaeration takes place in a specific rate depending on DO deficit. Many investigators have formulated models as an alternative to the Fickian Model for the advection dispersion pollutant transport. Since Streeter-Phelps research on BOD-DO modeling, many researchers have studied fate of pollutant considering first order reaction along with only advection. The Streeter-Phelps dispersion model includes deoxygenation and reaeration along with advection and dispersion and which has been solved by defining an axillary variable relating DO deficit and BOD concentration. Thus this paper considered first order decay and reaeration along with advection and dispersion to simulate spatial and temporal variation of DO concentration using a hybrid mixing cells model. The proposed model has been successfully applied for a hypothetical flow conditions and the River Brahmani, India. River flow requirement and regulation for pollutant disposal with pre-treatment were optimized using the responses of proposed model for this River. This research analyzed the selected river reach using proposed model having a particular flow and channel characteristics and found that release of 1180m3/s from Rengali Dam is required to avoid pollution problem. However, in absence of this flow at least 50% of pretreatment pollutants are required before released into river Tikira.