Milwaukee Water Works (MWW) added Ozonation facilities to both municipal water treatment plants at a cost of approximately $39 Million. These facilities went on-line in May and July 1998, respectively. Ozone disinfection was part of a much larger package of water system improvements designed to strengthen the multiple barrier approach to water treatment in Milwaukee. The total package included source protection via intake relocation, filter bed replacement, instrumentation and SCADA automation, and chemical feed improvements at a total cost of $89 Million. Ozone disinfection was selected as an effective barrier to further Cryptosporidium contamination in light of the 1993 outbreak. Coupling ozone treatment with biologically active filtration (BAF) was seen as a logical step to enhance multiple water quality objectives and fit current industry and regulatory trends toward organics removal. The Howard Avenue Plant made the transition to BAF operation in September 1998. The Linnwood Plant converted to BAF in July 2000. MWW continued a comprehensive DBP screening program that was implemented during the ICR and has been continued to-date. Because of concerns about potential increased levels of AOC, Bromate, and Aldehydes in the finished water resulting from ozonation, special emphasis was placed on the monitoring program for these parameters. In response to published papers concerning Ozonation Disinfection ByProducts (OBPs), MWW worked with a contract laboratory throughout the transition to the Ozonation/BAF treatment process to expand the OBP's screening program where possible. In October 1999 the Aldehyde monitoring list was expanded from 7 to 15 analytes. The HAA list was expanded to include HAA (9) in May 2000. 6 additional brominated analytes were added to the 551.1 list in June 2000. Subsequent studies suggested even further refinements to the OBP's monitoring program. This lead to a collaboration with EPA's National Exposure Research Laboratory (NERL) in Athens, GA to conduct a comprehensive DBP scan to identify other compounds in Milwaukee's ozone/BAF treated water in August 2002. Includes figures.
