On the basis of the biological filter, referring to the packing tower method in the chemical industry, a filter with a diameter to height ratio of 1:6 to 1:8 and a height of 8 to 24 meters was constructed. Due to its small diameter, large height, and tower like shape, it is called a tower biofilter, abbreviated as a "tower filter" biotower. Tower biofilters are also a type of structure that utilizes aerobic microorganisms to treat wastewater. They are a fundamental method for treating domestic and organic industrial wastewater using biofilm technology, and have been applied in wastewater treatment in industries such as petrochemicals, coking, chemical fibers, papermaking, and metallurgy. Through recent years of practice, it has been shown that tower filters have a good effect on treating toxic wastewater containing cyanide, phenol, nitrile, aldehyde, etc., and the treated effluent can meet the requirements. Due to its various advantages, it has been widely used.
Product Features
1) The hydraulic load of tower biofilters is 2-10 times higher than that of high load biofilters, reaching 30-200 meters per meter per day, and the BOD load is as high as 2000-3000 grams per meter per day. The influent BOD concentration can be increased to 500 milligrams per liter.
2) The tower filter has a height of 8-24 meters and a diameter of 1-3.5 meters, with a diameter to height ratio of about 1:6-1:8. This creates a strong air extraction state inside the filter, resulting in good ventilation. In addition, due to the high height and hydraulic load, the water flow in the pool is turbulent, and the contact between sewage, air, and biofilm is very sufficient. The high BOD load causes rapid growth of biofilm, but the high hydraulic load also causes strong hydraulic erosion of biofilm, resulting in continuous shedding and renewal of biofilm. All of these characteristics contribute to the metabolism and reproduction of microorganisms, which is beneficial for the degradation of organic pollutants.
product structure
The tower type biological filter adopts increasing the height of the filter layer to improve the treatment capacity of the filter. Generally, the height of the filter layer is between 8 and 16 meters, and even greater than 16 meters. On the plane, it is generally rectangular or circular, and its main parts include the tower body, filter material, water distribution equipment, ventilation device, and drainage system, as shown in the following figure.

1) Tower body
The tower body serves as a barrier and filter material. Brick structure, steel structure, reinforced concrete structure, or a hybrid structure of steel frame and plastic board surface can be used. Divide the entire tower into several layers along the height direction with a grid to support the weight of the filter material and biofilm. The filling height of each layer of filter material should not exceed 2 meters to avoid crushing the filter material.
2) Filter material
The requirements for the type, strength, and corrosion resistance of filter media are basically the same as those for ordinary biological filters. However, due to the height of the tower, if the filter material is heavy, the tower body must be reinforced with load-bearing structures, which not only increases the cost, but also makes the construction and installation more complex. Therefore, it is also required that the capacity of the filter material be small. In addition, tower filtration has a high load, rapid growth of biofilm, and high oxygen demand. Therefore, in addition to requiring a large surface area, the filter material also needs to have a large porosity to facilitate ventilation and discharge of detached biofilm. At present, a type of glass cloth honeycomb packing and large aperture corrugated plastic plate filter material has been developed both domestically and internationally, which combines the above two advantages and has been widely used.