A method for treating a leachate or a leachate concentrate loaded with mineral and organic constituents, the load of mineral and organic constituents comprising from 0.1% to 30% by weight of dry matter, wherein: a. the leachate or the leachate concentrate is introduced into an acidification tank in which an acid is added thereto and then, if necessary, an anti-foaming composition in order to obtain a mixture whose pH is in the range of 5 to 6.5, said mixture then being stirred for a period of 2hrs to 4hrs, preferably 3hrs, then the pH is neutralized (i) in the acidification tank or (ii) after having transferred said mixture into a settling tank, b. preferably using a bi-fluid spray rod, the leachate or the leachate concentrate treated at the end of step a. is sprayed in the form of microdrops in hot combustion gases, preferably hot biogas, having a temperature equal to or greater than 900°C into an atomizing device, said atomizing device comprising: - an air-cooled burner comprising spraying means (21, 22) adapted to form the microdrops of said leachate or leachate concentrate and to eject same in a first cone-shaped flux, and means (23, 24, 25) adapted to generate a second flux of said hot combustion gases having the shape of a larger cone than the first flux and at least partially surrounding the first flux; - a shaft having a tapered wall the narrow end of which defines an opening, with the first flux and the second flux reaching the internal volume of the tapered wall, through said opening, with the first flux and the second flux being oriented along the axis of said tapered wall, the second flux entering said internal volume as a concentric conical flow to cause a flash contact with the first flux at the burner outlet; gases comprising water vapors, dusts and combustion gases and optionally non-gaseous residues being obtained, c. the gases comprising water vapors, dusts and combustion gases obtained in step b. are transferred to a filtration device, preferably at a temperature of 130°C, then the dusts comprising the mineral and organic constituents are recovered, d. optionally, the gases from the filtration device of step c. are transferred to a plume allaying device. a. the leachate or the leachate concentrate is introduced into an acidification tank in which an acid is added thereto and then, if necessary, an anti-foaming composition in order to obtain a mixture whose pH is in the range of 5 to 6.5, said mixture then being stirred for a period of 2hrs to 4hrs, preferably 3hrs, then the pH is neutralized (i) in the acidification tank or (ii) after having transferred said mixture into a settling tank, b. preferably using a bi-fluid spray rod, the leachate or the leachate concentrate treated at the end of step a. is sprayed in the form of microdrops in hot combustion gases, preferably hot biogas, having a temperature equal to or greater than 900°C into an atomizing device, said atomizing device comprising: - an air-cooled burner comprising spraying means (21, 22) adapted to form the microdrops of said leachate or leachate concentrate and to eject same in a first cone-shaped flux, and means (23, 24, 25) adapted to generate a second flux of said hot combustion gases having the shape of a larger cone than the first flux and at least partially surrounding the first flux; - a shaft having a tapered wall the narrow end of which defines an opening, with the first flux and the second flux reaching the internal volume of the tapered wall, through said opening, with the first flux and the second flux being oriented along the axis of said tapered wall, the second flux entering said internal volume as a concentric conical flow to cause a flash contact with the first flux at the burner outlet; gases comprising water vapors, dusts and combustion gases and optionally non-gaseous residues being obtained, - an air-cooled burner comprising spraying means (21, 22) adapted to form the microdrops of said leachate or leachate concentrate and to eject same in a first cone-shaped flux, and means (23, 24, 25) adapted to generate a second flux of said hot combustion gases having the shape of a larger cone than the first flux and at least partially surrounding the first flux; - a shaft having a tapered wall the narrow end of which defines an opening, with the first flux and the second flux reaching the internal volume of the tapered wall, through said opening, with the first flux and the second flux being oriented along the axis of said tapered wall, the second flux entering said internal volume as a concentric conical flow to cause a flash contact with the first flux at the burner outlet; gases comprising water vapors, dusts and combustion gases and optionally non-gaseous residues being obtained, c. the gases comprising water vapors, dusts and combustion gases obtained in step b. are transferred to a filtration device, preferably at a temperature of 130°C, then the dusts comprising the mineral and organic constituents are recovered, d. optionally, the gases from the filtration device of step c. are transferred to a plume allaying device.