The City of Peoria's (City) Greenway Water Treatment Plant (GWTP) applies ozone
followed by conventional flocculation/sedimentation and biologically active granular activated carbon (GAC) filters in
treating its raw water. The GAC filters are used for removing particulates and in assisting in
the 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 raw
water, ozone dosages are kept to the minimum to keep the bromate level below the 10
micrograms/liter (µg/L) maximum contaminant level (MCL). By limiting the ozone dose, the
City is not able to maintain ozone residual at ozone contactor or achieve disinfection
credits with ozone.
The City believes that the ozonation and biologically active GAC filtration processes can be
further optimized to improve the removal of DBP precursors and T&O compounds while
the bromate formation is controlled or minimized. The City is especially interested in further
optimization for the following reasons:
an optimized ozonation step will ensure reliable compliance with the bromate
standard while increasing the disinfection ability for the unit process;
improving the removal of total organic carbon (TOC) through the optimized
operation of ozonation, coagulation and GAC filtration will reduce DBP
concentrations in distribution system, in particular, total trihalomethanes (TTHMs); and,
the optimized use of these combined processes will result in improving finished
water quality in terms of lowering TOC, DBPs and T&O compounds.
The City retained Malcolm Pirnie Inc. to conduct an evaluation to meet the following
objectives:
identify alternative methods to mitigate bromate formation during the ozonation
process; and,
conduct necessary bromate mitigation bench-scale tests and develop
recommendations for full-scale consideration. Includes reference, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.2 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 46 |
| Published : | 06/01/2007 |
