Coagulant for coking wastewater after biochemical treatment and treatment method thereof

The invention discloses a coagulant for coking wastewater after biochemical treatment and a treatment method thereof; the coagulant is prepared by adding the following raw materials in a liter of coking wastewater after biochemical treatment: 70-100 mg of active carbon, 50-60 mg of aluminium polychlorid, and 2-6 mg of polyacrylamide. The coagulant and the treatment method can allow the COD of the coking wastewater after biochemical treatment to reach the national and discharge standards, wherein the COD is not more than 300 mg/L, the chroma is not more than 160 times, and the suspended matter is not more than 200 mg/L. The treatment method is simple and practical; the cost is low; the produced solid wastes can be used as fuel; no new wastes are generated; and the purpose of energy saving and emission reduction is realized.