SYSTEM FOR TREATING COAL GASIFICATION WASTEWATER, AND METHOD FOR TREATING COAL GASIFICATION WASTEWATER

Provided is a system for treating coal gasification wastewater, whereby it becomes possible to remove a cyan compound, a fluorine compound, a selenium compound, ammonia nitrogen and a COD component contained in the coal gasification wastewater with high efficiency to achieve satisfactory quality of treated water, to reduce the content of a toxic substance in produced sludge, and can dispose waste materials easily. A system for treating coal gasification wastewater, which is equipped with: a high-temperature alkaline chlorination treatment unit (10) for decomposing at least a cyan compound, ammonia nitrogen and a COD component by such a high-temperature alkaline chlorination treatment that an oxidizing agent is added and the reaction is carried out under warmed conditions; a fluorination treatment unit (50) for removing at least a fluorine compound by a coagulation-sedimentation treatment and/or an adsorption treatment; and a selenium treatment unit (52) for removing a selenium compound by such a reduction removal treatment that the selenium compound is reduced and then the reduced selenium compound is removed and/or an adsorption treatment. In the system, the fluorination treatment unit (50) and the selenium treatment unit (52) are arranged downstream of the high-temperature alkaline chlorination treatment unit (10).