Subsurface Wastewater Treatment Equipment refers to the wastewater treatment technology where the main structures of the treatment facility are buried underground or semi-underground. It is characterized by a small footprint, low noise, no odor, minimal impact from climate, easy management, and high treatment efficiency.

The buried sewage treatment equipment refers to a technology that integrates various functions of sewage treatment processes, including pretreatment, biological treatment, sedimentation, and disinfection, into a single unit for residential sewage treatment, which is buried underground. Currently, the buried integrated treatment technology is categorized by process, including biological contact oxidation, SBR method, A/O, and A2/O processes. The treatment unit can be manufactured as a prefabricated steel structure for overall installation or as a steel-concrete structure cast on-site.

The buried sewage treatment equipment boasts mature technology, minimal land use, excellent treatment performance, and a wide range of applications, serving as a valuable supplement to urban sewage treatment systems and providing a new approach for the treatment of domestic wastewater from small, scattered pollution sources. 1. The entire equipment system is equipped with an automatic electrical control system and a device fault alarm system, ensuring reliable operation and typically requiring no human management, just timely maintenance and care. 2. The buried sewage treatment equipment is installed below the ground surface, allowing the surface above to be used for landscaping or other purposes without the need for construction or heating/insulation. 3. The biochemical pool employs the biological contact oxidation method, with a low volume load of fill material, keeping microorganisms in the self-oxidation phase, resulting in minimal sludge production. Sludge is only required to be removed once every 90 days or more (by pumping with a manure truck or dewatering into a sludge cake for external transport). 4. The odor control for this buried sewage treatment equipment includes both conventional high-altitude exhaust and additional soil deodorization measures. 5. The two-stage biological contact oxidation process uses a plug flow design, offering superior treatment performance compared to complete mix or two-stage series complete mix biological contact oxidation pools. It is also smaller in volume than an activated sludge pool, highly adaptable to water quality, with good resistance to shock loads, stable effluent quality, and no sludge bulking. The pool utilizes new elastic three-dimensional fill material, with a large specific surface area, facilitating easy colonization and shedding of microorganisms. Under the same organic load conditions, it achieves high organic matter removal rates and improves the solubility of oxygen in water.