Domestic Sewage Treatment Equipment

Domestic sewage treatment equipment is designed to treat sewage generated from daily life, including wastewater from laundry, bathing, toilets, kitchens, and other domestic activities. The relevant introduction is as follows:

Working Principle

The removal of organic pollutants and ammonia nitrogen (NH₃-N) by domestic sewage treatment equipment mainly relies on the AO biological treatment process integrated in the equipment.

• In the Level A anoxic tank, the microorganisms are facultative microorganisms. These microorganisms can reduce nitrate nitrogen and nitrite nitrogen in the sewage to gaseous nitrogen, which escapes into the air. At the same time, they decompose recalcitrant macromolecular organics into small-molecule, easily degradable substances, reducing the organic load on the subsequent aerobic tank.

• In the Level O aerobic tank, aerobic microorganisms decompose organics into CO₂ and H₂O. Autotrophic bacteria (nitrifying bacteria) use inorganic carbon produced by organic decomposition or CO₂ from the air as a nutrient source, converting NH₃-N in the sewage into nitrite nitrogen (NO₂⁻-N) and nitrate nitrogen (NO₃⁻-N). A portion of the effluent from the Level O tank is refluxed to the Level A tank, and nitrogen pollution is eliminated through denitrification.

Equipment Types

1. Powered Underground Integrated Treatment Equipment

Classified by process, it includes biological contact oxidation process, SBR (Sequencing Batch Reactor), A/O (Anaerobic-Oxic), A²/O (Anaerobic-Anoxic-Oxic), and other technologies.

• Features: Can be buried underground, occupying no surface area; low noise, little odor, and minimal impact on the surrounding environment; high purification efficiency, low sludge production; high degree of automation, and easy management.

2. Small Domestic Sewage Purification Biogas Digester

It applies normal-temperature anaerobic fermentation technology and is composed of processes such as anaerobic fermentation, facultative digestion and filtration, sewage reflux, and fillers, following the principle of "multi-stage gravity flow and gradual degradation".

• Most organics in domestic sewage produce biogas after anaerobic fermentation. The fermented sewage then enters the facultative digestion and filtration tank, where some undegraded organics are further degraded.
• Features: Low investment, good treatment effect, and no energy support required for operation.

3. Physicochemical Treatment Equipment

It includes physical treatment equipment (such as sedimentation tanks and screens) and equipment that treats sewage through chemical methods (e.g., coagulation, flocculation, redox). It can remove solid impurities, dissolved substances, and harmful substances from sewage.

Process Flow

The general process includes the following stages: influent → grille → equalization tank → pretreatment tank → anaerobic tank → anoxic tank → aerobic tank → sedimentation tank → disinfection tank.

1. Sewage first passes through the grille to remove impurities of different sizes.
2. It then enters the equalization tank to adjust water quantity and quality.
3. Reagents are added in the pretreatment tank to reduce the sewage concentration.
4. The sewage then flows into the anaerobic tank, anoxic tank, and aerobic tank in sequence for biochemical treatment.
5. Solid-liquid separation is carried out in the sedimentation tank.
6. Finally, the sewage is disinfected in the disinfection tank (via UV or chemicals) before being discharged up to standard or reused.

Application Scope

Suitable for domestic sewage treatment in residential areas, restaurants, hotels, sanatoriums, schools, mines, factories, etc., as well as similar industrial sewage treatment.