In the painting industry, electrocoating paint technology is widely used due to its efficient and uniform coating effects. However, the wastewater generated during the electrocoating process contains a large amount of organic matter, heavy metal ions, and solid suspended matter. If not treated rigorously, it will cause severe environmental pollution. Therefore, how to cleanly treat electrocoating paint wastewater has become an urgent issue that needs to be addressed.

　　The process of treating electrocoating paint wastewater typically includes several steps: pretreatment, biochemical treatment, advanced treatment, and chemical treatment. Firstly, the pretreatment stage mainly removes large particulate suspended matter and floating oil from the wastewater through physical methods. The wastewater enters a sedimentation tank where large particles settle naturally, and then, with the help of flocculants, fine suspended matter and colloidal particles are aggregated into flocs for subsequent separation. An oil-water separator is used to remove floating oil and some organic matter.

　　Next is the biochemical treatment stage, which uses the metabolic action of microorganisms to decompose the organic matter in the wastewater. Anaerobic treatment first sends the wastewater into an anaerobic reactor, such as UASB, where anaerobic microorganisms convert organic matter into methane and carbon dioxide, while removing some heavy metal ions. Subsequently, aerobic treatment sends the wastewater into an aerobic tank, where aerobic microorganisms further decompose organic matter and convert ammonia nitrogen into nitrate nitrogen.

　　The advanced treatment stage further purifies the water quality through physical and chemical methods. A secondary sedimentation tank is used to separate the remaining suspended matter and activated sludge after aerobic treatment, followed by filtration through a sand filter or activated carbon filter to remove fine suspended matter and some dissolved organic matter. The adsorption method uses materials such as activated carbon to adsorb residual organics and heavy metal ions. Membrane treatment technologies, such as nanofiltration or reverse osmosis, are used to remove dissolved solids and heavy metal ions.

　　In the chemical treatment stage, for organics that are difficult to biodegrade, chemical oxidation methods such as ozone oxidation or hydrogen peroxide oxidation can be used to convert them into harmless substances. At the same time, chemical precipitation can be used by adding chemical agents to the wastewater to form insoluble precipitates of heavy metal ions for removal.

　　Finally, the sludge produced during the treatment process needs to be dewatered, stabilized, and rendered harmless to prevent secondary pollution. These sludge treatment steps are an indispensable part of the electrocoating paint wastewater treatment process.

　　In summary, the treatment of electrocoating paint wastewater is a complex process that requires the comprehensive application of multiple technologies and methods. Through these steps, the harmful substances in the wastewater can be effectively removed, allowing it to meet discharge standards and protect the environment from pollution. With the increasing awareness of environmental protection and continuous technological advancements, electrocoating paint wastewater treatment technology will also continue to improve, providing support for the sustainable development of the painting industry.