METHOD FOR TREATING PAPERMAKING WASTE WATER AND METHOD FOR UTILIZING SILICA SOL IN PAPERMAKING

摘要

There is provided a method for treating papermaking waste water, which comprises having a silica-aluminum based inorganic polymer flocculant having an Si/Al molar ratio of 0.2 to 1.5 contained in papermaking waste water having a pH or adjusted pH of 5 to 14 such that the concentration of the inorganic polymer flocculant becomes 1 to 250 (mg-Al/L) in terms of aluminum to control the pH of the papermaking waste water to 5 to 8 and then adding an organic polymer flocculant.;The method for treating papermaking waste water has high suspended material flocculation efficiency and can flocculate suspended materials without leaving fine suspended materials and produce a flocculated precipitate which can be recycled as a valuable resource.