NOVELTY - The method comprises: providing an energy-rich process water stream; optionally filtering the energy-rich process water stream for creating an energy-rich process water filtrate stream; and feeding the energy-rich process water stream or the water filtrate stream to a membrane distillation unit (120) comprising a membrane creating a heated side and a non-heated side within the distillation unit, where the energy-rich process water stream or the energy-rich process water filtrate stream contacts the heated side for creating a membrane distillate stream and an energy-rich aqueous liquid.    USE - The method is useful for improving efficiency of a water-containing industrial process consisting of a boiler system, food processing, dairy processing, beverage processing, landfill leachate processing, and/or biofuel processing (all claimed).    ADVANTAGE - The method is capable of economically improving the efficiency and sustainability of the water-containing industrial process, thus reducing the generation of steam, and hence the amount of fuel needed to generate steam is reduced.    DETAILED DESCRIPTION - The method comprises: providing an energy-rich process water stream; optionally filtering the energy-rich process water stream for creating an energy-rich process water filtrate stream; feeding the energy-rich process water stream or the energy-rich process water filtrate stream to a membrane distillation unit (120) comprising a membrane creating a heated side and a non-heated side within the membrane distillation unit, where the energy-rich process water stream or the energy-rich process water filtrate stream contacts the heated side of the membrane for creating a membrane distillate stream and an energy-rich aqueous liquid; optionally feeding a salinated stream and the energy-rich aqueous liquid into a forward osmosis unit (140) comprising a membrane creating a first side and a second side within the forward osmosis unit, where the salinated stream is fed to the first side, and the energy-rich aqueous liquid is fed into the second side for creating a concentrated stream (13) and a diluted stream (15); preliminarily purifying a stream comprising one of the energy-rich aqueous liquid and the diluted stream using a technique consisting of reverse osmosis, ion exchange and/or water softening for creating a purified makeup water stream; and feeding the purified makeup water stream and the membrane distillate stream into a heated thermal industrial water system. The energy-rich process water is discharged from the heated thermal industrial water system. The heated thermal industrial water system is a boiler system (100), and the purified makeup water stream and the membrane distillate stream are combined into a single stream prior to being fed into the boiler system. The energy-rich process water is a blowdown water from a boiler system, and a condensate water from an industrial process. Prior to the filtering step, the energy-rich process water is treated with a compound consisting of a coagulant, a flocculant, and/or an adsorbent. The stream being preliminarily purified further comprises raw water. The preliminary purification technique is reverse osmosis. The filtering step utilizes one of ultra filtration, micro filtration, and media filtration. The salinated stream comprises a reverse osmosis reject stream. The forward osmosis unit is operated in forward osmosis mode or operated in pressure retarded osmosis mode. An INDEPENDENT CLAIM is included for a method for improving efficiency of a heated thermal industrial water system.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a system used to carry out a method for improving efficiency of a water-containing industrial process.    Concentrated stream (13)    Diluted stream (15)    Boiler system (100)    Membrane distillation unit (120)    Forward osmosis unit. (140)