treppõhusti, kaskaadõhusti, õhustustrepp
reast astmetest või kaldpindadest koosnev ehitis, mille pinnal voolates rikastub vesi hõlpsamini hapnikuga, an aerating device built in the form of either steps or an inclined plane, on which are placed staggered projections arranged to break up the water and bring it into contact with air
