Metal wastewater refers to wastewater containing heavy metals discharged from industrial production processes such as mining, machinery manufacturing, chemical industry, electronics, and instrumentation. The heavy metals in heavy metal wastewater generally cannot be decomposed and destroyed, but can only be transferred to other locations and their physical and chemical forms. The treatment method for heavy metal wastewater is to treat it on-site at the production site, usually using chemical precipitation method, ion exchange method, etc. After treatment, the heavy metal content in the water is lower than the discharge standard and can be discharged or reused.