AWWA ACE70754

This powerpoint presentation begins by providing a brief overview of disinfection byproducts (DBP), along with stand pipe aeration and chlorine contact basin aeration as potential solutions for controling DBPs in small water systems. Aeration kinetic basics of equilibrium are presented, along with Henry's Constant TemperatureCorrection Equation. Experimental methodology included a bench-scale study of diffused aeration to assess selected design variables of air flow rate, contact time (air/water ratio), diffuserarrangement (bubble size), and selected operating conditions including air temperature, water temperature, and THM concentration. Bench scale experimentalconclusions:water temperature and air to water ratiohave a significant effect on removals;air temperature and initial concentrationdid not have a significant effect onremovals; and,bubble distribution did not appear to havea significant effect on overall removals. The diffused aeration assessment summary indicates: a simple air diffuser can be placed in a storage tank orchlorine contact basin for THM removal;effective for small system THM compliance;no removal of HAAs;most effective for chloroform; and,most effective during warm weather months. A pilot-scale study on spray aeration included:evaluating the role of temperature on spray aerationremoval rates;developing a relationship between percent removals andphysical characteristics of aeration equipment withrespect to Henry's constants of THM species; and,assess the role of operating parameters (e.g. operatingpressure / head loss and flow rate) in determining masstransfer coefficients and interfacial surface area (KLa). Spray aeration pilot schematic is presented, and conclusions indicated: aeration provides a way to remove THMs after theyhave formed with a minimal capital investment;temperature has a significant effect on removalefficiencies;diffused aeration can achieve significant removalsbased on air to water ratio; and,spray aeration can achieve significant removals ofTHMs dependent primarily on shower head type anddroplet travel distance. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2009

Number of Pages:

40

File Size:

1 file , 2.9 MB