Method for processing sludge in steel rolling direct cooling recirculated cooling water system

The invention relates to a method for processing sludge in a steel rolling direct cooling recirculated cooling water system. The method is characterized by comprising the following steps of: arranging a medicine addition device at a rolling mill's whirling well of the steel rolling direct cooling system and adding a coagulant; adding an oil removing agent into a chemical degreaser; and allowing all the sludge in a mud pit to directly return into the rolling mill's whirling well. The method has the following advantages: recycling coagulation of sludge is realized and clearance of suspensions and oils in the system is high; subsequent sludge press filtration equipment in an original technology can completely stop operating and the operation cost is greatly reduced; the recovery rate of scale is increased, sludge in the recovered scale is little and will not influence the quality of scale; and the medicine addition amount of the coagulant and the oil removing agent is reduced by about 30-50%.