Automobile manufacturing is a highly integrated process. From stamping, welding, painting to assembly, each link is accompanied by different types of industrial wastewater. It is characterized by dispersed water sources, complex components, and strong volatility. In particular, the drainage of the coating line, cleaning section, and electrophoresis treatment system has a high pollution load and is difficult to treat. It is a typical "multi-cause integrated" comprehensive management problem.
Sewage characteristics:
Diverse water sources and cross-sections: wastewater comes from multiple links such as pretreatment, phosphating, electrophoresis, painting, cleaning, grinding, and testing. The types of pollutants are rich and the components vary greatly, requiring systematic classification and management.
Organic matter and heavy metals coexist: COD is usually 800–3,000mg/L, BOD₅ is 300–800mg/L, and it also contains high-risk substances such as phosphates, nitrates, grease, surfactants, and heavy metals (zinc, chromium, nickel).
High oil content and strong emulsion stability: Some cleaning wastewater contains a large amount of emulsified oil and cutting fluid, which is difficult to completely remove by traditional flotation. The oil concentration can reach 200-500mg/L, requiring special separation and demulsification technology.
The water quality in the coating section fluctuates violently: Due to factors such as color conversion and batch switching, the pH of electrophoresis and spraying wastewater can fluctuate greatly between 4-10, which has a great impact on the system.
Strict emission standards must be met and stable: Usually, it is necessary to meet local ultra-clean emission requirements, and heavy metals, total phosphorus, COD, etc. are strictly controlled.
Accurately identify and classify and collect according to the nature of the work section, set up modules such as demulsification + flotation oil removal + flocculation sedimentation + biochemical treatment + membrane deep purification, and the system is more targeted and efficient.
Through chemical precipitation + electroflocculation + chelating agent removal technology, the stable removal rate of heavy metals such as zinc, chromium, nickel, and lead is ≥95%, ensuring the dual safety of the environment and equipment.
Using a combination of high shear demulsification + DAF flotation + AO biochemical system + MBR membrane bioreactor, the chromaticity, COD, oil and fat of the treated effluent are better than the emission standards.
After deep treatment, wastewater is reused for flushing, spray pretreatment, and circulating cooling systems, with a reuse rate of 60-80%, significantly reducing new water consumption and operating costs.
Equipped with a cloud data platform, it supports remote monitoring, data tracking, intelligent adjustment, and abnormal warning to achieve cost reduction, efficiency improvement, and green operation.
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