Treatment and recycling of white water in papermaking machinery and equipment

Treatment and recycling of white water in papermaking machinery and equipment

White water is the waste water of papermaking machinery and equipment. White water mainly contains fine fibers, fillers, pigments and dissolved wood components, and adds rubber, wet strength agents, preservatives, etc., insoluble COD, low biodegradability, and added preservatives. certain toxicity. The water of white water is relatively large, but its organic pollution load is lower than that of cooking black liquor and intermediate wastewater. Now almost all paper uses a partially or completely closed system to reduce water consumption and power consumption. , Improve the white water recovery rate and reduce excess white water discharge.

1. Air flotation method for papermaking white water treatment

Air flotation is more commonly used in white water treatment, the substances contained in white water are short fibers, fillers and colloidal solutes, after conditioning, mixing and dissolving in water are reduced flotation, after flotation separation operation, clean water tank into water, return to paper machine, short fibers Pulp enters the pool and returns to the paper machine. Air flotation is widely used in my country's papermaking enterprises, using separate flotation of fibers, fillers and water to obtain good results, and the treated water is recycled.

2. The treatment and reuse process of white water in papermaking machinery and equipment uses the air delivery pipe at the bottom of the diffuser at the speed of the impeller rotation in the water to form a vacuum area vortex submerged underwater for aeration, and the air is sucked into the water surface On the surface, the resulting microbubbles spiral up to the surface, and oxygen in the air enters the water as well. In the float process, fine air bubbles are attached to the float, the air bubbles from the float reaching the liquid are kept supported on the surface of the liquid, and the gas flow is removed by a radial thrust. The drive (or chain) grinder moves along the entire liquid surface, pushes the floating material from the inlet to the outlet of the floating box, puts the inclined metal plate into the floating box, and transfers the collected sludge into the sludge tank, so that the purification process of white water treatment It's finished.