Treatment of Heavy Metal Wastewater by Electroflocculation

Metallurgical wastewater is generally acidic, and contains zinc, lead, copper, nickel, arsenic and other heavy metal ions. It also contains suspended matter, fluoride, nitrate and various organic matters. Therefore, such wastewater needs to be pretreated and recycled into wastewater treatment system. To achieve the goal of Metallurgical Wastewater Discharge and reclaimed water reuse.

Pretreatment process

This kind of wastewater is firstly neutralized and precipitated by adding calcium hydroxide, and fluoride is removed at the same time. Then the wastewater enters the Aeration Sedimentation tank, which oxidizes the ferrous and arsenic in the wastewater into ferrous and arsenic pentavalents. As a result of many times of neutralization and precipitation, a large number of different chemicals are added to the wastewater, resulting in an increase in the hardness and salinity of the wastewater. To soften, the softened wastewater enters the high-efficiency thickener for settling, overflows into the comprehensive regulating tank, underflows into the filter press for dehydration, and filtrate returns to the regulating tank.

Electrochemical standard-attaining treatment process

The pretreated wastewater enters the electrochemical (electroflocculation) wastewater treatment system, realizes the redox reaction in the heavy metal wastewater treatment process, removes part of the organic matter and most heavy metal ions in the wastewater, and enters the aeration sedimentation tank after the electrochemical system effluent enters the reaction sedimentation tank to remove suspended matter, and then enters the Aeration Sedimentation tank. Iron and arsenic are oxidized to iron and arsenic respectively. The effluent enters the deep filtration system, and then filters through the filtration system and enters the intermediate storage tank.