Abstract: A method for treating a circulating water in a wet paint booth, the method including adding a treatment agent including an aqueous solution including a tannin and an alkali metal hydroxide and/or an alkali metal carbonate to the circulating water in any of passages for the circulating water in the wet paint booth, wherein the passages include for supplying the circulating water from a water tank to a paint booth, for collecting an uncoated paint in the circulating water, and for returning the circulating water to the water tank; to detackify the uncoated paint collected in the circulating water.

Abstract: A method for treating a wet-painting booth circulation water, includes, into somewhere along a path for a wet-painting booth circulation water supplied from a water tank to a painting booth for collecting an unapplied paint and then returned to the water tank, adding a treatment agent to a wet-painting booth circulation water so as to detackify the unapplied paint collected in the circulation water, wherein the treatment agent includes a cellulose acetate solution.

Abstract: An adequate control of a pH of circulating water circulating through a wet paint booth enables an efficient coagulation treatment of a paint included in the circulating water. A method for treating circulating water circulating through a wet paint booth and including a paint includes treating the paint included in the circulating water by adding an alkaline solution of a phenolic resin to the circulating water, and adjusting a pH of the circulating water to 6.5 to 8.0. An amount of the alkaline solution of the phenolic resin added to the circulating water is increased when the pH of the circulating water is a predetermined value of 8.0 or less. An acidic aluminum salt is further added to the circulating water. An amount of the acidic aluminum salt added to the circulating water is increased when the pH of the circulating water is a predetermined value of 6.5 or more.

Abstract: A method for treating a circulating water in a wet paint booth, the method including adding a treatment agent including an aqueous solution including a tannin and an alkali metal hydroxide and/or an alkali metal carbonate to the circulating water in any of passages for the circulating water in the wet paint booth, wherein the passages include for supplying the circulating water from a water tank to a paint booth, for collecting an uncoated paint in the circulating water, and for returning the circulating water to the water tank; to detackify the uncoated paint collected in the circulating water.