TREATMENT OF GEOTHERMAL HOT WATER

PURPOSE:To reduce the precipitation and the adhesion of dissolved silica to machineries, by a method wherein dissolved silica in geothermal hot water containing dissolved silica in an oversaturated state is grown to a particle with a specific particle size which is in turn separated from hot water by an ultrafiltration membrane. CONSTITUTION:In utilizing geothermal hot water, soluble oversaturated silica in hot water is subjected to colloid growth or coagulation to be grown to a particle with a particle size of 5mmu or more which is in turn separated by using an ultrafiltration membrane to reduce the precipitation of dissolved silica in the filtrate to machineries. In this case, a temp. in colloid growth conditions is pref. about 40-100 deg.C and, in forming and growing a secondary coagulation particle by adding a coagulant, as the coagulant, an Al type, an Fe type, a Ca type or an org. amines are effective.