The City of Columbus’ Hap Cremean drinking water treatment plant will be converted to the use of ozone and biologically active filtration (BAF) by 2013. The change is driven by the EPA Stage 2 Disinfection Byproducts rule that takes effect in 2012. The Hap Cremean plant has a capacity of 100 MGD. A variety of alternatives treatments were considered during the planning stage including GAC and membrane filtration.
The system will be designed with a maximum ozone dose of 7 mg/l and an average dose of 5.3 mg/l. The ozone transfer efficiency is expected to be in the range of 91%. Bromate, a potential ozone disinfection byproduct, is expected to be 1.6 micrograms/l, well below the 10 microgram/l EPA limit. The ozone/BAF is expected to reduce TOC levels an additional 14-24 percent versus the current treatment methods.