An apparatus for purifying water, such as for desalinization, includes a
source of a heated air stream, the heated air stream having a temperature
above an ambient temperature. A diffusion tower having high surface area
material therein receives a water stream including at least one impurity
and creates at least one region having thin films of water therein from
the water stream. The heated air stream is directed over the thin films
of water to create a humidified air stream that is at least substantially
saturated. At least one direct contact condenser is in fluid
communication with the humidified air stream for condensing the
humidified air stream, thus producing purified water. A power plant can
include the apparatus for purifying water, where energy to heat the air
stream is provided by low pressure condensing steam.