Due to the lack of local facilities for recycling, neutralization and treatment of wastewater at many metallurgical enterprises the wastewater is mixed; surface wastewater, blowdown of recycled water supply cycles, chemically polluted wastewater, spent cooling and washing liquids. As a result of the joint processing of the mentioned waste waters in sewage treatment plants, the specific sediments containing compounds of heavy metals and toxic substances are formed. The data on metal content in a solid phase of mixed sediments of different metallurgical enterprises is presented. It is noted that toxicity of sediments can be reduced by excluding the discharge of used concentrated solutions into the sewerage system, by regeneration of used technological and detergent solutions at the place of their formation. The scheme of sludge processing, which provides for their flocculation, gravitational thickening and mechanical dewatering, is proposed. It is shown, that the most efficient flocculant for treatment of sludge of mixed composition is a high-molecular-weight anionic flocculant with the content of ionogenic groups up to 10 %. The effective dosage is 5-7 kg/t dry solids of sludge. For mechanical dewatering of flocculated sludge, chamber, membrane and belt filter presses as well as screw centrifuges (decanters) can be applied. Depending on the metal content, the dewatered sludge can be used for technical remediation of disturbed areas or for processing in the cement industry. Present study shows a schematic diagram for the preparation of mixed sewage sludge and dry industrial wastes of a metallurgical plant for technical remediation of disturbed lands. For processing sludge with water content between 65-75 % in cement industry it is recommended to mix the mechanically dewatered sludge with dry wastes, such as abrasive dust and grinding powders, waste core mixtures for casting and other similar wastes.