The pretreatment of painting workshop,electrophoresis and traditional Venturi spray booth can produce a large amount of wastewater.With the development of technology and the promotion of environmental awareness,environmental regulations have also made obvious requirements on the painting waste water treatment,which do not allow heavy metals in the wastewater,and some areas require zero emission of nitrogen and phosphorus,and improve the discharge grade of wastewater.In order to reduce wastewater discharge,water reuse has gradually become an inevitable choice in the coating workshops.