TREATMENT OF WASTE WATER

• Main Author: KUBO KATSUHISA
• Format: Patent
• Language: English
• Published: 07.09.1992
• Subjects: CHEMISTRY; METALLURGY; TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE

PURPOSE:To lower the COD of the treated water to the level lower than the level obtainable with the conventional methods by first adding an inorg. flocculating agent to waste water to flocculate its turbidity components, then adding a mixture composed of the metal salt and polymerized silicic acid which can form the hydroxide of a polynuclear complex salt in the presence of water thereto to flocculate the soluble COD. CONSTITUTION:The waste water is first subjected to a flocculation treatment to flocculate its turbidity components by adding the inorg. flocculating agent (e.g.: alum) thereto. The mixture composed of the metal salt (e.g.: aluminum chloride) and polymerized silicic acid which can form the hydroxide of the polynuclear complex salt in the presence of water is added thereto to flocculate the soluble COD component. This polymerized silicic acid can be produced by using, for example, commercially marketed water glass as a raw material and polymerizing this water glass under an acidic condition. This method is applied to the treatment of waste water and the waste water of waste paper in particular and can remove the soluble COD components which are difficult to remove by the conventional flocculation treatments. The COD of the treated water is thus lowered to the level lower than the level of the conventional methods.