The soft filler is connected by spun fibers and pressed with plastic discs with evenly distributed fiber filaments to form a unit fiber bundle of a fixed length. The fiber filaments are spread horizontally in the water and distributed evenly. The biofilm is easy to knot and has a large specific surface area. . It is widely used for the aerobic treatment of industrial wastewater and domestic sewage such as printing and dyeing, oil refining, wool spinning, silk, pharmaceutical, cyanide, petrochemical, etc., and also suitable for anaerobic treatment of high-concentration wastewater such as hemp spinning, alcohol, sugar, paper, food, and fermentation. Semi-soft filler has high heat dissipation, low resistance, good water and air distribution performance, easy to grow film, and has a foam cutting effect. It is made of polypropylene material and is suitable for sewage and wastewater treatment projects. It is also used in contact oxidation towers, Oxidation ditch, oxidation tank and other equipment.