AWWA JAW31550

Inclined cascade aeration (ICA) was effective in removing 10 chlorinated volatile organic chemicals (VOCs) from drinking water at liquid loadings of 5 gpm/ft (1.04 L s-1/m) to 15 gpm/ft (3.1 L s-1/m). Overall mass transfer (or desorption) coefficients (KLav) were an order of magnitude larger (0.08-0.54 s-1) than those reported for packed-tower aeration. A curve fit of the experimental data for all 10 VOCs with the equation KLav = 0.019 + 0.091 (Hp)1/4(sinO)4/3, in which Hp is the Henry's law constant (atm) and O is the angle of inclination, yielded desorption coefficients within plus or minus 18 percent of experimental values. A cascade angle of 60 was found most efficacious for compounds with Hp values > 300 atm; compounds with Hp values < 300 atm were most effectively stripped at yet steeper angles. Includes 37 references, tables, figures.