AWWA ACE65606

The City of Peoria's (City) Greenway Water Treatment Plant (GWTP) applies ozonefollowed by conventional flocculation/sedimentation and biologically active granular activated carbon (GAC) filters intreating its raw water. The GAC filters are used for removing particulates and in assisting inthe removal of disinfection byproduct (DBP) precursors and taste and odor (T&O)compounds from raw water. Due to the presence of moderate levels of bromide in City's rawwater, ozone dosages are kept to the minimum to keep the bromate level below the 10micrograms/liter (µg/L) maximum contaminant level (MCL). By limiting the ozone dose, theCity is not able to maintain ozone residual at ozone contactor or achieve disinfectioncredits with ozone.The City believes that the ozonation and biologically active GAC filtration processes can befurther optimized to improve the removal of DBP precursors and T&O compounds whilethe bromate formation is controlled or minimized. The City is especially interested in furtheroptimization for the following reasons:an optimized ozonation step will ensure reliable compliance with the bromatestandard while increasing the disinfection ability for the unit process;improving the removal of total organic carbon (TOC) through the optimizedoperation of ozonation, coagulation and GAC filtration will reduce DBPconcentrations in distribution system, in particular, total trihalomethanes (TTHMs); and,the optimized use of these combined processes will result in improving finishedwater quality in terms of lowering TOC, DBPs and T&O compounds.The City retained Malcolm Pirnie Inc. to conduct an evaluation to meet the followingobjectives:identify alternative methods to mitigate bromate formation during the ozonationprocess; and,conduct necessary bromate mitigation bench-scale tests and developrecommendations for full-scale consideration. Includes reference, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2007

Number of Pages:

46

File Size:

1 file , 1.2 MB