METHOD OF REMOVING PHOSPHORUS IN WATER

PROBLEM TO BE SOLVED: To use an adsorbing volcanic ash soil granular matter consisting of volcanic ash soil consisting essentially of allophane which can be easily reused to remove phosphorus in water containing phosphorus of a low concentration and to prolong the life of the adsorbing volcanic soil granular matter. SOLUTION: Volcanic ask soil having chemical composition of 18 to 24 wt.% Si, 23 to 29 wt.% Al, and 1 to 5 wt.% Fe and consisting essentially of allophane is granulated to obtain spheroidal granular matter of 0.5 to 0.7 bulk density and >=25% in-water breakdown rate substantially containing no additive. In this method of removing phosphorus from water by using adsorbing volcanic ask soil granular matter consisting of the spheroidal granular matter, after coagulant is added to water to be treated, it is passed through a packed bed of the adsorbing volcanic ask soil granular matter.