Soft fiber filler is a biological carrier used in the biological contact oxidation method and anaerobic fermentation method for wastewater treatment. It features a large specific surface area, high utilization rate, variable voids that prevent clogging, strong adaptability, stable resistance to impact loads, reduced sludge production, easy management, low construction cost, economical operation, and convenient assembly. This filler is made from aldehyde-treated polyvinyl formal fiber as the base material, processed to simulate the form of natural aquatic plants.

Combination filler is developed on the basis of soft filler and semi-soft filler, combining the advantages of both. Its structure involves replacing the plastic disc buckle with a double-ring large plastic ring, pressing aldehyde-treated fiber or polyester filament onto the ring loop to ensure even distribution of the fiber bundles; the inner ring consists of snowflake-shaped plastic branches, which not only support biofilm attachment but also effectively cut bubbles, enhancing oxygen transfer rate and utilization. This allows full exchange of water, air, and biofilm, enabling efficient treatment of organic matter in water.