Method and system for biochemical reduction of oily sludge in cold rolling wastewater

The invention relates to the technical field of environmental protection, in particular to a method and a system for biochemical reduction of oily sludge in cold rolling oily wastewater, the method comprises the following steps: removing suspended solids and particulate matters in the cold rolling oily wastewater to obtain pretreated wastewater, CODcr in the cold rolling oily wastewater is less than or equal to 7000 mg/L, and CODcr in the cold rolling oily wastewater is less than or equal to 7000 mg/L; the concentration of suspended solids in the pretreated wastewater is less than or equal to 300mg/L, and the pH value of the pretreated wastewater is 6.5-8; carrying out anaerobic biochemical treatment on the pretreated wastewater to degrade organic matters in the pretreated wastewater to obtain primary purified water and biogas; mixing the primary purified water with domestic sewage to obtain mixed sewage; the mixed sewage is subjected to biochemical anoxic treatment, biochemical aerobic treatment, precipitati