Iron hydroxide coagulating sedimentation processing method of the concentrated inorganic component containing wastewater

摘要

PROBLEM TO BE SOLVED: To highly treat wastewater containing an inorganic component in high concentration.;SOLUTION: A first process - a third process are successively performed. The first process is process for adding a water soluble ferric salt aqueous solution to wastewater containing a thick inorganic component and, if ferric ions are mixed with wastewater in the first process, the pH of wastewater is lowered by a water soluble ferric salt showing weak acidity. The second process is a process for neutralizing the ferric salt added to wastewater by alkali and ferric ions are reacted with hydroxyl ions in the second process to form an iron hydroxide precipitate. Further, heavy metal components in wastewater are also precipitate as hydroxide. The third process is a process for succeedingly repeating the first and second processes once or more. By successively performing these processes, an iron hydroxide flocculated precipitate excellent in sedimentation properties, filterability and dehydration properties is obtained in wastewater.;COPYRIGHT: (C)2002,JPO