The main source of the zinc from the waste water of the electroplate and metal-processing industry is the liquid produced during the process of electroplate and acid pickling. The pollutant will be left in the rinsing water after the rinse. The acid pickling procedures is made up of the following steps: firstly, immerse the metal (Zinc or copper) into the liquid of strong acid to remove the oxide on its surface, then into the brightener with strong chromic acid to enhance its gloss.

The waste water contains a large quantity of heavy metal ion such as hydrochloric acid, zinc, copper and the organic brightener, which will be harmful to the health and even cause cancer and distortion to the human bodies. It is essential to recycle the electroplating wastewater in a proper way to prevent its severe pollution to the environment.

The treatment system for electroplate mixed waste water consists of regulating tank, dosing tank, reduction pool, neutral reaction pool, PH value adjusting tank, flocculation pool, inclined tube sedimentation basin, chamber filter press, pure water tank, air flotation reaction and active carbon filter.

The electroplate waste water treatment system adopts the interior electrolytic process of scrap iron, which mainly depends on the purified effluents of the activated industrial waste scrap water. When the waste water contacts with the additives, it will cause electrochemical reaction, chemical reaction and physical effects, including catalysis, oxidation, reduction, replacement reaction, coprecipitation, flocculation and adsorption, which can remove various metal ion in the waste water to purify the water.