Method for treating circulating water in paint booths

The invention relates to a method for the treatment of circulating water in paint booths, whereby the paint particles are dispersed by adding dispersants selected from the group consisting of: a) homopolymers and copolymers based on maleic acid, acrylic acid and/or methacrylic acid with a molar mass ranging between 2500 and 500 000; b) non-ionic surface active agents; c) anionic surface active agents, whereby no polyaspartic acid is additionally added to the circulating water in said case and d) inorganic or non-polymeric organic complexing agents and mixtures thereof, their total concentration ranging from 0.01 to 2.0 percent by weight in relation to the circulating water. According to said method for the treatment of circulating water in paint booths, the circulating water has a hardness of at least 2 DEG measured in accordance with the German water hardness system. By adding dispersants in a concentration ranging between 0.001 and 2.0 percent by weight in relation to the circulating water, the paint particles are dispersed in such a way that they have a mean particle size of less than 20 mu m determinable by laser diffraction.