Grantee Research Project Results
1998 Progress Report: Hydrodynamics of Initial Mixing Zones of Wastewater Discharges
EPA Grant Number: R826216Title: Hydrodynamics of Initial Mixing Zones of Wastewater Discharges
Investigators: Roberts, Philip J.W.
Institution: Georgia Institute of Technology
EPA Project Officer: Aja, Hayley
Project Period: October 1, 1997 through September 30, 2000
Project Period Covered by this Report: October 1, 1997 through September 30, 1998
Project Amount: $277,643
RFA: Exploratory Research - Physics (1997) RFA Text | Recipients Lists
Research Category: Water , Air , Safer Chemicals , Land and Waste Management
Objective:
The objectives of the study are to obtain experimental data on the physics of turbulent mixing processes in buoyancy-modified flows typical of industrial and municipal wastewater discharges. The data will be used to refine the mathematical models of dilution and mixing zones used by EPA, and to test the hypothesis that the end of the initial hydrodynamic mixing zone is caused by turbulence collapse under the influence of gravitational forces.Progress Summary:
The past year has been dedicated primarily to the complex task of designing an integrated laser scanning and high-speed imaging system capable of imaging the flows in three dimensions. The specifications for this system are now complete. Some components have already been received and some are on order.The laser scanning system consists of two-axis galvanometer mirrors with components made by Cambridge Technology. We have received these components and have integrated them into the existing optical system. The scanners are driven by an analog waveform supplied by a National Instruments data acquisition card. We have developed the software to do this, and have investigated the characteristics of the mirrors, including their range of scanning speeds and inertial characteristics. We have made a light sheet and tested it with fluorescent dye calibration standards and our present digital camera.
The high-speed video imaging system will consist of a Pentium Xeon computer with 2 gigabytes of memory. The camera is a Dalsa CD-6, capable of 260 frames per second, each frame 512 by 512 pixels. The images will be written directly to system memory through a PCI-bus frame grabber, then saved to disc. This system has been ordered, and delivery is expected early in 1999.
The camera, image capture, and laser beam sweep will be controlled by the National Instruments board. This will provide synchronization between the laser and image capture.
Future Activities:
The next major tasks involve integration of the full imaging and laser scanning systems. The software to do this will be developed. Following this, we will thoroughly test and calibrate the system for pixel response as a function of beam sweep rate and amplitude, exposure time, and dye concentration. The optimal parameters for our system for the flows to be investigated will then be determined.We will then begin experiments with the actual flows to be investigated. These include typical wastewater discharges into rivers, lakes, and coastal waters.
Journal Articles:
No journal articles submitted with this report: View all 2 publications for this projectSupplemental Keywords:
water, toxins, discharge, mixing zone, mathematical models, dilution., Scientific Discipline, Water, Environmental Chemistry, Wastewater, Hydrology, Physics, municipal wastewater treatment, three dimensional model, estuaries, industrial wastewater, dilution, wastewater discharges, mathematical model, initial mixing zones, high speed imaging, discharge, National Pollutant Discharge Elimination System (NPDES), laser induced fluorescence, hydrodynamicsRelevant Websites:
http://www.water.ce.gatech.edu/Research/Mixing/movie.gif
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.