Overview of urban sewage treatment processes: Aerated biological filter
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Keywords: Urban wastewater treatment processes; Biological Aeration Filtration; Process overview. Biological Aeration Filtration is a treatment system in which packing is installed within a biological filter, and artificial oxygen supply is provided to enable the growth of a large number of microorganisms on the packing. An aerated biological filter consists of a filter bed, a gas distribution device, a water distribution device, a drainage device, etc. The aeration device uses specialized aeration nozzles; the small and medium-sized bubbles generated are repeatedly fragmented by the packing, thereby achieving an effect similar to that of micro-controlled aeration. Due to the high sludge concentration in the reaction tank and the compact design of the treatment facility, it is possible to **save space and reduce reaction time. Process flow and process characteristics: ① It overcomes sludge bulking, ensures stable treatment performance, and simplifies operation and management. ②It changes the traditional air supply method of natural ventilation in high-load biological filters, replacing it with artificial oxygen supply to enhance the treatment efficiency and improve the quality of the effluent. ③It has a strong capacity to withstand impact loads, making it particularly suitable for the treatment of municipal wastewater in modern cities where industrial wastewater accounts for an increasingly larger proportion. ④Biological fillers interact with the air, which can significantly improve oxygen utilization efficiency. ⑤As needed, it can be combined to form an A2/O process with biological phosphorus and nitrogen removal functions. ⑥Special aeration heads for small and medium bubbles are used, eliminating the problems of clogging and cracking that are common with microporous aeration heads. ⑦It uses special biological fillers developed by Beijing Sand Environmental Protection Industry Group, resulting in a high sludge concentration, compact treatment facilities, and a small footprint. Application scope: Medium and small-scale municipal wastewater treatment plants
However, compared to traditional activated sludge systems, the investment is higher. Managing operations is relatively complex.
The most important aspect of the aerated biological filter is the pretreatment stage at its inlet. This biochemical process was originally developed by the French company Veolia, and it was put into use at the Malanshan wastewater treatment plant in Dalian, China. Subsequently, several domestic research institutions filed patents for this technology, and many wastewater treatment plants were established in various locations; Yuanrenfu Bioengineering Company in Sichuan carried out numerous projects of this kind, such as the Meishan wastewater treatment plant. In terms of actual performance, removing COD is not a major issue, but the removal of N and P is ineffective; especially for N, the energy consumption is high, the operating costs are higher compared to traditional activated sludge processes, the pretreatment steps are complicated, and operation and management are complex. Of course, its greatest advantage is simply its space-saving nature.