Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Truax, D. Dennis

Committee Member

Magbanua Jr., S. Benjamin

Committee Member

Martin, L. James

Date of Degree

12-15-2007

Document Type

Graduate Thesis - Open Access

Major

Civil Engineering

Degree Name

Master of Science

College

James Worth Bagley College of Engineering

Department

Department of Civil and Environmental Engineering

Abstract

The aeration potential of a low profile cascade aerator was studied under varying operational conditions in accordance with the ASCE Standard for Measurement of Oxygen Transfer in Clean Water [ASCE 2-06, 2007]. Operational parameters delved into included the channel slope (2.50, 4.50 and 6.50); water flow rate (465.75 L/min.m (37.5 gpm/ft), 931.45 L/min.m (75 gpm/ft) and 1397.20 L/min.m (112.5 gpm/ft)); and weir geometry (rectangular-shaped, inverted T-shaped, W-shaped and inverted Cross shaped weir). The oxygen transfer coefficient, KLa, was derived by use of a FORTRAN-based nonlinear regression analysis computer program and served to assess the effectiveness of various combinations of operational parameters. Statistical tests (ANOVA analysis and main plot, interactive plot) were performed on the results to determine the optimal operating conditions. It was discovered that the combination of the inverted Cross shaped weir and flow rates of 1397.20 L/min.m (112.5 gpm/ft) produced the highest reaeration rates for all slope considered. On the other hand, the W-shaped weir produced better reaeration values at lower flows of 465.75 L/min.m (37.5 gpm/ft) and 931.45 L/min.m (75 gpm/ft) for the range of channel slopes examined. These effects can be respectively attributed to the strong turbulent mixing generated by the plunging nappe flow and recirculating air vortices, which apparently led to substantial air entrainment in the water mass.

URI

https://hdl.handle.net/11668/15685

Download

Share

COinS