The media has the advantages of simplicity and ease of operation, and the equipment itself does not cause any environmental pollution. Moreover, due to different environments and wastewater treatment targets, various types of media have emerged in the market, catering to the needs of different industries and targets for wastewater treatment. They are applied in the environmental management and various sectors requiring wastewater treatment. It can be said that media is an essential component in today's focus on environmental protection. In the future development, continuous improvement of technology and updating of equipment will be made to better adapt to different needs, contributing further to the advancement of environmental protection.

Filling materials can be traced back to the primitive stage of amorphous substances such as coke and stone. The introduction of Raschig rings in 1914 marked a significant breakthrough in the filling tower. Raschig rings are solid wall rings with both inner and outer surfaces, which, compared to the original filling material, have a larger surface area. However, when placed horizontally, the inner surface is not easily wetted by the liquid. The development of the Pall ring filling material ushered in a new era of ring-shaped packing with holes in the wall and a tongue piece inside. Subsequently, improved Pall rings and stepped ring fillings were introduced. The stepped rings have a high-to-diameter ratio of only 0.3, with a low center of gravity, and exhibit a certain degree of regular arrangement during random stacking, thus offering low resistance, high flow rates, and excellent performance.

In recent years, as society places greater emphasis on environmental causes and the demand for a higher quality of life increases, environmental protection has become a deeply rooted topic. As a result, equipment like fillers, which specialize in wastewater treatment within the environmental sector, are now being widely applied in various locations in need. Currently, China's efforts in wastewater treatment are a crucial task within the realm of environmental protection, as water quality and safety are not only related to sustainable environmental development but also closely tied to people's daily lives. The application of fillers in wastewater treatment has gained widespread recognition. By injecting oxygen into wastewater, fillers help alleviate pollution levels to meet discharge standards, thereby reducing repetitive pollution of water resources and achieving environmental protection goals.

Fillers are an effective and environmentally friendly solution for water resource management, differing from some chemical treatment methods that can cause pollution during the process. The fillers employ physical methods to expel harmful gases or substances from wastewater into the air, and then inject oxygen into the water to create an aerobic cycle. This approach preserves the environment while effectively reducing harmful substances in the wastewater. Designed to handle the diversity and complexity of pollutants in water, fillers undergo multi-stage treatment to meet discharge standards. With the development of cities and the advancement of industrialization, it is inevitable that wastewater that does not meet discharge standards will arise. Since it is not feasible to completely shut down these enterprises for societal development, reducing water pollution becomes a top priority. This necessitates a certain level of expectation for the role of fillers in wastewater treatment.