CH2M HILL made a twist on the usual placement of a dissolved air flotation (DAF) system, placing it at the beginning of the process train rather than in the solids-treatment train, where it is usually located in wastewater treatment facilities.
A decade ago, Pima County's Regional Wastewater Reclamation Dept., or RWRD, was facing a problem: The Arizona Dept. of Environmental Quality had ruled that the levels of nitrogen coming from RWRD's network of 10 wastewater-stripping and treatment plants were too high.
