The invention belongs to the technical field of
wastewater treatment, and particularly relates to a method for treating
oily wastewater in catering industry. The invention provides the method for treating the
oily wastewater in the catering industry with simple operation and good oil removing effect. The method comprises that (1) a
polyferric sulfate demulsifying agent is added into the
oily wastewater, the adding amount of the demulsifying agent is 0.2 to 2 milligrams per
liter, and the mixture is stirred evenly, wherein the
polyferric sulfate is cationic, reduces the surface activity of
anionic detergent, and breaks hydrated films of emulsified liquid oil droplets and double
electrode layer structures thereof so as to separate out oil; and meanwhile the
polyferric sulfate is acid, and can covert
fatty acid soap in the emulsified liquid into water-insoluble
fatty acid so as to reduce surface active substances in the water and increase the demulsifying effect; (2)
sodium humate flocculating agent and
polyacrylamide are added into the
wastewater obtained in the step (1), the adding amount of the
sodium humate is 0.1 to 0.4 milligrams per
liter, the adding amount of the
polyacrylamide is 40 to 100 milligrams per
liter, and the mixture is stirred evenly; and (3) the oil and the water are separated by using the gravity principle.