TREATMENT METHOD OF ZINC-CHROME ELECTROPLATING WASTEWATER

PURPOSE: Provided is a treatment method of zinc-chrome electroplating wastewater which removes organic matter(COD) and heavy metal ion in zinc-chrome electroplating wastewater efficiently by using reverse osmosis film and vacuum evaporation concentration. Further, the final condensed water can be recycled to plating process. CONSTITUTION: The method comprises (i) the first stage which separates primary condensed water and permeated water from zinc-chrome electroplating wastewater by passing through reverse osmosis film(30) of which void size is below 10Å by pressure of 16 to 18kg/cm¬2; (ii) the second stage which flows the primary condensed water into vacuum evaporation concentration process and drains the permeated water; (iii) the third stage which separates secondary condensed water from the primary condensed water by vacuum evaporation concentration in the temperature range of 70 to 75°C and under -550 to -600 mmHg of vacuum condition; (iv) the last stage which recycles the secondary condensed water and drains the condensed water. The fixed volume of primary condensed water is recycled. The permeated and condensed water is used for washing plating wastewater and the secondary condensed water is used for plating.