The invention relates to a method for treating alkali residue
liquid waste and three-
sludge of oil refineries. The method comprises the following steps: at first, contacting the alkali residue
liquid waste of oil refineries with an
oxygen-containing gas at 100-200 DEG C and at a pressure of 0.3-3 MPa to carry out a mild
wet oxidation treatment, so as to convert
sulfur in sulfides into sulfates and / or
thiosulfates, mixing the alkali residue
liquid waste experiencing the oxidation treatment with the three-
sludge of oil refineries in a mixing and stirring tank, adding a coagulant, a flocculant,
magnetic powder and an oxidant into the mixing and stirring tank, reacting for a period of time, and carrying out
solid-liquid separation on materials at the outlet of the mixing and stirring tank in a
magnetic separator, wherein the separated water can be directly drained or recycled, and the separated
solid is further dewatered after the
magnetic powder is recycled. According to the method provided by the invention, the COD removal rate is up to 99%, and the
water content of the
dewatered sludge is smaller than 60%. The method provided by the invention is simple in treatment process, little in equipment, short in dwell time, simple and convenient to operate and high in treatment efficiency.