AWWA ACE68920

This powerpoint presentation begins by providing a brief overview of modified slow sand filtration. Two methods of predicting the performance of modified slow sand filtration are presented, including: bench-scale studies that are generally used to predict equipment performance; and, physical and chemical treatment that is relatively easy to evaluate on benchscale. An example of ozone-assisted biofiltration at the First Nation (Aboriginal) Community in Northern Ontario, Canada, is provided and includes the following: raw water with high (> 20 mg/L) DOC & Color (85 TCU); poor historical raw water quality information; and, bench-scale method used before incurring the expense of a pilot trial; ozone applied at O₃/DOC ratios of 0.5 up to 1.5 (0.5 mg O₃ per mg DOC), ozone dosages ranged from 5 to 30 mg/L; and, samples analyzed for DOC, BDOC, color, UV254, SUVA, general chemistry, bromate. Results of bench-scale study included the following: 15 - 27% of the DOC mineralized by ozone; 33 - 36% of the remaining DOC converted to BDOC; and, potential for > 57% DOC removal IF biofiltration can remove 100% of BDOC. Includes table, figures.