Abstract: A process and an apparatus is presented for at least partially extracting a liquid from an aggregate, by evaporation in a stream of carrier gas, followed by separation of at least a portion of the evaporated liquid from the stream of carrier gas. The separation comprises expanding the higher moisture contents stream to a lower pressure so as to effect cooling and resulting liquid condensate from the gas stream, recompressing the cold stream with retained latent heat of vaporization thereby further heating the stream, and discharging the resulting heated stream with the lowered moisture content at an appropriate section of the circuit. In accordance with the present invention, the expansion and the compression take place in a wave pressure exchanger.