Methods for purifying aqueous waste streams containing a water reducible paint composition and equipment systems capable of conducting such methods are provided. In general terms the methods can be practiced by first providing an aqueous waste stream comprising a minor amount of a water reducible paint composition. This aqueous waste stream will commonly have a water content of at least 95 percent by weight. An acid, preferably sulfuric acid, is then admixed with the aqueous waste stream to form a suspension comprising water and precipitated paint compounds. Following the precipitation step a portion of the precipitated paint compounds are separated from the water.