Underground domestic sewage treatment equipment is a modular treatment system developed for decentralized sewage discharge scenarios. By burying the main structure underground and combining core processes such as biological treatment, sedimentation filtration, and disinfection, it achieves efficient removal of pollutants such as COD, BOD ₅, ammonia nitrogen, and total phosphorus in domestic sewage. Due to its characteristics of occupying less land, strong adaptability, and stable operation, it has become the mainstream sewage treatment choice for residential areas, villages, hospitals, hotels, and scenic spots, effectively filling the gap of insufficient coverage of centralized sewage treatment pipelines.

　　The device core consists of four functional units, forming a complete processing chain. As the first line of defense, the preprocessing unit includes a grid pool and a regulating pool: the grid accurately intercepts large debris such as plastic bags and leaves in the sewage, avoiding equipment blockage in the future; The regulating tank balances water quality and quantity fluctuations through volume buffering to prevent impact loads from affecting biological treatment efficiency. The biological treatment unit is the purification core, and the mainstream uses A/O, MBR or SBR processes: the A/O process achieves nitrogen and phosphorus removal through the synergy of anaerobic and aerobic bacterial communities; MBR technology utilizes membrane components to enhance solid-liquid separation and improve effluent quality; The SBR sequencing batch operation mode is suitable for scenarios with significant water quality fluctuations. Deep processing units are mostly sedimentation tanks or filtration tanks, which further intercept suspended particulate matter; The disinfection unit is equipped with ultraviolet or chlorine dioxide generators to kill pathogenic microorganisms and ensure that the effluent meets the standard.

　　Underground domestic sewage treatment equipment

　　Compared to traditional sewage treatment facilities, its advantages are particularly prominent. The most significant feature is the land saving. After the main body is buried underground, the surface can be planned for greening, parking lots, etc., and the land utilization rate can be increased by more than 60%, perfectly adapting to the tight land situation in urban core areas, scenic spots, and other areas. The treatment efficiency is stable and reliable. The domesticated mature microbial community can achieve a COD removal rate of over 85% and an ammonia nitrogen removal rate of over 80%. The effluent generally meets the Class A discharge standard, and some can be directly reused. The operation and maintenance costs are controllable, and the PLC automatic control system realizes real-time monitoring of parameters such as liquid level and dissolved oxygen, reducing manual intervention. The operating cost per ton of water is only 0.5-1.5 yuan; The fully enclosed structure can effectively isolate odors and noise, with minimal impact on the surrounding environment.

　　The device has a wide range of application scenarios, which not only solve the problem of sewage discharge in areas without centralized pipeline networks such as villages and suburbs, but also adapt to restricted places such as residential areas and hospitals. It can also meet the temporary treatment needs of construction sites, camping sites, and other places. However, in the application, attention should be paid to avoiding the location of groundwater source protection areas and geologically soft areas to prevent the risk of groundwater leakage; At the same time, it is necessary to regularly clean the grille, maintain the aerator and disinfection equipment, and conduct comprehensive maintenance every 1-2 years. The selection should be based on the actual treatment water volume of 5-500 cubic meters per day to avoid overloading operation.

　　In summary, buried domestic sewage treatment equipment has become a key equipment for decentralized sewage treatment due to its spatial advantages of "underground concealment and above ground utilization", combined with efficient and stable treatment performance and low-cost operation and maintenance characteristics. With the integration of intelligent upgrading and recycled water reuse modules, its application boundaries are constantly expanding in the construction of a water-saving society, providing flexible and efficient technical support for sewage purification and resource utilization in different scenarios, and helping to achieve the governance goal of "sewage purification and resource recycling".