an aftercooler apparatus that is connected to a turbocharger and to a reciprocating engine has a primary and a secondary saturation chamber , and a drying chamber . turbocharged air from the turbocharger is directed into the primary saturation chamber . the incoming air is initially mixed with and cooled by water located at the bottom of the primary saturation chamber before being directed through a diffusion screen . the air exiting the diffusion screen enters the secondary saturation chamber where intense bubbling and foaming increases the air - water contact area to further cool the air and form an air - water mixture approaching the temperature and moisture level of saturation . the air - water mixture is then directed into the drying chamber where a majority of the moisture is removed from the air through the use of centrifugal force . the now cooler moist air is directed toward the engine intake manifold , whereby the moisture in the air stream acts to reduce the nox formation during the combustion process . the aftercooler apparatus acts to reduce the formation of nox emissions from turbocharged engines rather than attempting to remove the nox emissions from the exhaust stream of the engines . the aftercooler apparatus may also be used to beneficially recycle industrial waste waters .