How Is Sewage Treatment Equipment Composed?

Before the sewage enters the equipment for operation, a regulating tank is set up to adjust the sewage's quality and quantity. The effective retention time in the regulating tank is generally 6 to 9 hours. A grille net box is installed at the inlet of the regulating tank to intercept large particles of debris in the sewage and ensure the normal operation of the pump.

1. Grille

A grille is set at the direction of the regulating tank inlet. The grille is used to capture small floating objects and suspended particles in the sewage, preventing debris from blocking the pump impeller and causing the motor to burn out. This section is part of the pre-treatment stage.

2. Anoxic Tank

The anoxic tank is set up for denitrification. After the sewage is separated by the grille, it is pumped to the anoxic tank where it mixes with the return nitrified liquid from the contact tank. Fillers are placed in the anoxic tank as carriers for denitrifying bacteria. These fillers are effective in removing nitrogen, phosphorus, and sulfides, with a retention time of 2 hours. When combined with the sludge tank in the previous process, it forms an A/O (anaerobic/oxic) treatment process, which achieves the goals of phosphorus and nitrogen removal.

3. Biological Contact Oxidation Tank

The retention time is 6 hours, using three-dimensional elastic fillers. These fillers have a large specific surface area, with a treatment load of 14 kg BOD/m³·d, which is 5-10 times that of regular fillers. The biochemical tank uses a micro-porous aeration disc for aeration, and the sewage circulates continuously in the biochemical tank, fully contacting the biological film on the filler, enabling the rapid degradation of organic matter.

4. Secondary Sedimentation Tank

After biological treatment, the sewage flows into the secondary sedimentation tank. The design surface load of the secondary sedimentation tank is 0.9-1.2 m³/m²·d. The sedimentation tank is equipped with a lifting and adjustable liquid level, and a toothed water collection tank for uniform water collection and effective sedimentation. The sludge from secondary sedimentation is pumped to the sludge tank.

5. Disinfection Tank

According to national standard TJ14-74, the disinfection tank has a retention time of 30 minutes. The disinfectant used is solid chlorine tablets or bleaching powder, which is generally added once a week.

6. Sludge Tank

The debris intercepted by the grille and the sludge from the secondary sedimentation tank both enter the sludge tank. The sludge tank is equipped with a sludge nitrification system, and the supernatant liquid from the sludge tank flows back to the regulating tank.

7. Fan Room and Automatic Control Cabinet

The fan room is set up separately and contains fans and control cabinets. The fan room's exhaust pipe is connected to the equipment's intake pipe, with a distance not exceeding 15 meters.