PHOSPHORUS REMOVING METHOD

摘要

PROBLEM TO BE SOLVED: To inexpensively remove phosphorus contained in water. SOLUTION: Fly ash generated from a coal steam power plant is utilized as a seed crystal and soluble calcium contained in fly ash is used as a calcium ion source and the alkalinity of fly ash is utilized to provide a crystallizing dephosphorization method not requiring the addition of calcium ions and a pH control agent. In this method, water to be treated containing phosphorus is brought into contact with fly ash under a condition of pH 9-12 to remove phosphorus. Carbonate ions lowering dephosphorization efficiency are preliminarily reacted with calcium ions eluted from fly ash before crystallizing dephosphorization reaction to be sedimented and separated as calcium carbonate.