NOVELTY - A treatment apparatus for cleaning and converting waste gas from tail pipes into and reuse its dynamofluidal properties comprises a container with a suitable liquid, gas guide-in pipes through which some or all of the waste gas is supplied, gas discharge pipes, and a transmission windmill disposed inside or outside the gas pipe.    USE - The apparatus and method are cleaning and converting waste gas from tail pipes, including chimneys of factories, vehicles, boats and aircrafts (all claimed) into useful gas for e.g. driving windmill in generating power and for operating other machines (all claimed).    ADVANTAGE - With the set-up and method, it is possible to reuse resources from waste gas to provide energy in addition to petroleum and other fossil fuels, and also to ultimately improve air quality and environment greatly (all claimed).    DETAILED DESCRIPTION - A treatment apparatus for cleaning and converting waste gas from tail pipes into and reuse its dynamofluidal properties comprises a container with a suitable liquid, gas guide-in pipes through which some or all of the waste gas is supplied, gas discharge pipes, and a transmission windmill disposed inside or outside the gas pipe, in which the waste gas is introduced to contact with the liquid for purification by removing e.g. odor, dust, oil impurities and other residues, the oxygen consumed during combustion can provide moisture for wetting the gas flow introduced, and the cleansed gas is too discharged with excess oxygen for conversion into useful gas for recycling.    INDEPENDENT CLAIMS are also included for (1) similar treatment apparatuses with modification to provide further cleaning of the waste gas particularly after circulating through several treatment units by pumping, to retain useful materials, to discharge various materials safely and to prevent noise pollution; (2) apparatuses for incorporating the treatment apparatus into the waste-discharge systems of factories, kitchens, incinerators, vehicles, various engines, power-generating plants, hospitals farms etc. to clean and convert the waste gas into useful gas for recycling; and (3) a method for cleaning and converting waste gas into useful gas for reuse by applying the gas-treatment apparatus with incorporation into the various waste-discharge systems.