Waste solution solidifying agent, process for preparing the same and use of the same

An object of the present invention is to provide a waste solution solidifying agent which can solidify a waste solution, particularly, a waste solution containing blood or body fluid at a low cost, uniformly, and in a short time; in particular, to provide a waste solution solidifying agent which can solidify a waste solution uniformly and in a short time in a vertically oriented waste solution equipment. As a means of achieving this object, a waste solution solidifying agent of the present invention is a particulate treating agent used in a method of treating a waste solution which solidifies a waste solution into a gel by placing a treating agent in a waste solution, and is characterized in that said agent contains, as an essential component, a water-absorbent resin having a crosslinked structure obtained by polymerizing a water-soluble ethylenic unsaturated monomer and, when flowing-placed at once into a 0.90 mass % aqueous sodium chloride solution, 20 to 95 mass % of the agent is floated, and 80 to 5 mass % is settled. And a process for preparing a waste solution solidifying agent of the present invention is a process for preparing a particulate waste solution solidifying agent containing, as an essential component, a water-absorbent resin having a crosslinked structure obtained by polymerizing a water-soluble ethylenic unsaturated monomer, and comprises a step of mixing a hydrophobic substance having a methanol index of 20 or more after polymerization.