The filtration process using 15-20 micron pores is called microfiltration, and microporous filtration is a mechanical filtration method. It is suitable for maximizing the separation of tiny suspended substances (pulp fibers) present in liquids, achieving the purpose of solid liquid separation. It is widely used in the filtration of wastewater from papermaking, textile, printing and dyeing, chemical, food and other industries, especially in the treatment of papermaking wastewater, achieving the goal of closed circulation and reuse.