WATER PURIFICATION METHOD COMBINING FINE PARTICLE-MAKING METHOD AND MEMBRANE SEPARATION METHOD

PROBLEM TO BE SOLVED: To provide a new water purification method which removes organic matter and inorganic matter coexisting in a state dissolved and dispersed in wastewater and feed water under a condition where the consumption of thermal energy is low. SOLUTION: In the water purification method, positively charged ferric hydroxide colloidal particles are added to contaminated water to be treated and then an aqueous ferrous salt solution is added thereto to perform agitation while aerating the water. Alkaline water is added under agitation to adjust the pH of the water to be treated to 6-8 to generate fine particles. The water to be treated is left to stand to settle and separate the fine particles, and is filtered with a porous membrane or purified by a pore diffusion-filtration method. Substances which can be removed by this method are ions forming a complex with multiply-charged ions, such as arsenic ions, silicate ions, and cyanide ions, and iron ions and fine particles stably dispersed in an aqueous solution in a charged state. COPYRIGHT: (C)2011,JPO&INPIT