Abstract: A process for treatment of water containing an azole-type anticorrosive for copper, includes adding ferrous ions to the water containing the azole-type anticorrosive for copper and having a pH of 4-8, thereby precipitating an insoluble iron-azole complex, and separating the insoluble iron-azole complex. An amount of the ferrous ions added is 0.5 to 5.0 times, by molar ratio, an amount of the azole-type anticorrosive for copper in the water containing the azole-type anticorrosive for copper. After the insoluble iron-azole complex is separated, remaining total organic carbon (TOC) components are subjected to an ozone treatment.

Abstract: Provided is a process for efficiently removing an azole-type anticorrosive for copper from water containing the azole-type anticorrosive for copper, such as wastewater discharged from a CMP step in a fabrication process of a semiconductor device. Ferrous ions are added to water containing an azole-type anticorrosive for copper, and a resulting insoluble iron-azole complex is separated. After the insoluble iron-azole complex is separated, the remaining TOC components are subjected to ozonolysis. The azole-type anticorrosive for copper can be efficiently insolubilized in the form of an iron-azole complex using ferrous ions, and flocculation/solid-liquid separation can be performed. The water after removal of the insoluble matter formed by the addition of ferrous ions is water from which not only the azole-type anticorrosive for copper but also suspended solids have been removed.