Date of Award

2018

Degree Type

Dissertation

Degree Name

Doctor of Engineering

Department

Washkewicz College of Engineering

First Advisor

Hung, Yung-Tse

Subject Headings

QUAL2K Simulation, DO Sag, Critical Distance, Stream Classification, Wastewater Treatment, Stream Classification

Abstract

Modeling water quality has been shown to be a useful tool in strategizing water quality management. Dissolved oxygen (DO) has one of the largest impacts on water quality compared to other parameters. The purpose of the dissertation research is to generate a regression equation model, using the US EPA QUAL2K model as the base, to determine different factors affecting minimum dissolved oxygen concentrations in streams, to determine the critical distance for the minimum dissolved oxygen concentration, and the magnitude of impact of each parameter. Based on regression analysis, the factors affecting minimum DO in river water are effluent biochemical oxygen demand, effluent flow rate, river flow rate, river temperature, and effluent DO in that order. The simulation study of QUAL2K is related to stream classification and degree of treatment of municipal wastewater. Important factors affecting minimum dissolved oxygen concentrations in streams and corresponding critical distance or critical time in streams, which receive municipal wastewater treatment plant effluent discharge, include effluent BOD, river Q, effluent Q, and river temperature. Based on regression analysis, the factors affecting minimum DO in river water are effluent BOD, effluent Q, river Q, river temperature, and effluent DO, in that order. The application of the end result of this study can be used to determine the degree of municipal wastewater treatment to maintain a desirable stream classification and river water quality.

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