METHOD OF TREATING STRONGLY ACID WASTEWATER CONTAINING TOXICSUBSTANCES

摘要

A method of treating a strongly acid wastewater containing a harmful substance. By the method, harmful substances such as fluorine, boron, copper , lead, arsenic, hexavalent chromium, and cadmium can be safely removed from wastewaters without fail. The method, which is for treating a strongly acid liquid (1A) containing a harmful substance, comprises conducting the followi ng steps in this order: an adsorption/precipitation step (S1) in which hydroxyapatite (11) is mixed with the strongly acid liquid (1A) to precipita te the harmful substance as a solid matter; a neutralization step (S2) in which an alkaline substance (12) is mixed with the treated acid liquid (3A) containing the solid matter precipitated to neutralize the liquid (3A); and a coagulation step (S3) in which the treated liquid (4A) which has been neutralized is mixed with a coagulant (13) to coagulate the solid matter precipitated. The harmful substance in the strongly acid liquid (1A) can be effectively fixed and can be removed in a safe form. The concentration of th e harmful substance in the liquid can be lowered through the treatment. There is no need of heating the liquid in each step and the treatment can be carried out at ordinary temperature. The harmful substance can hence be treated safe ly.