WASTE LIQUID TREATMENT METHOD

PROBLEM TO BE SOLVED: To provide a waste liquid treatment method by which a component 1 and a component 2 are efficiently taken out from a waste liquid produced in a manufacturing process of a printed circuit board. SOLUTION: The method is characterized in that, In a evaporation concentration treatment performed in a concentration vessel 15 by heating the waste liquid consisting essentially of the component 1 having fixed solubility to water even when the temperature is increased and the component 2 having solubility in water higher than that of the component 1 and increased with the temperature rising, after the concentration vessel 15 is cleaned at first, a crystal deposited in more than saturated solubility in the component 1 to reach the saturated solubility in the first time by supplying the waste liquid to the concentration vessel 15 and heating in the concentration vessel 15 is taken out as the crystal by a filtration means 17 while dehydrating with dehydrating air and steam, and next, the waste liquid is cooled before the component 2 contained in the waste liquid reaches the saturated solubility and the component 2 reaching the saturated solubility at a cooling temperature and crystallized is taken out as a crystal by the filtration means 17 while dehydrating. COPYRIGHT: (C)2004,JPO