Abstract: A fuel nozzle comprises a body (1) with a cylindrical sleeve (2) accommodating a tubular element (3) having an axially extending channel (16). At the end of the element (3) there is arranged an acoustic head (5) having a conically shaped surface (6) adapted to generate acoustic vibrations. An annular recess (12) is formed on the surface (6). The nozzle body (1) carries a reflecting surface (9) formed as a plurality of pyramids. The fuel nozzle is provided with a device (18) adapted to swirl the gas flow and a regulating element (17) accommodated in the axial channel (16).

Abstract: A method of treating effluent sludge, which comprises coagulating sludge with mineral coagulants, thereafter subjecting the sludge to mechanical dehydration. The dehydrated sludge is dried to a moisture content of from 10 to 50 percent with the aid of a gaseous heat carrier having an initial temperature of from 600.degree. to 800.degree. C under backflow and air-gushing conditions. Dried sludge is introduced into the raw sludge at the coagulation stage at a rate so as to provide for a concentration of the resultant sludge mixture of from 50 to 120 g/lit.