Wastewater treatment method

Wastewater treatment includes physical treatment, chemical treatment and biological treatment.

First, physical therapy.

1. The methods of separating and recovering insoluble suspended pollutants (including oil film and oil beads) in wastewater by physical action can be divided into gravity separation, centrifugal separation and screen filtration interception.

2. The treatment units belonging to gravity separation method include sedimentation and air flotation (air flotation), and the corresponding treatment equipment includes grit chamber, sedimentation tank, oil separation tank, air flotation tank and its accessories.

3. Centrifugal separation method itself is a kind of treatment unit, and the treatment devices used are centrifugal separator and water cyclone separator. Screen filtration interception method has two processing units: mesh screen interception and filtration. The former uses grids and screens, while the latter uses sand filters and microporous filters.

4. The treatment method based on heat exchange principle also belongs to physical treatment method, and its treatment unit includes evaporation and crystallization.

Second, chemical treatment.

1. wastewater treatment method, through chemical reaction and mass transfer, separates and removes dissolved and colloidal pollutants in wastewater or converts them into harmless substances.

2. In the chemical treatment method, the treatment units based on chemical reaction by adding chemicals are coagulation, neutralization, redox and so on. The treatment units based on mass transfer include extraction, stripping, stripping, adsorption, ion exchange, electrodialysis and reverse osmosis.

3. The latter two treatment units are also called membrane separation technology. Among them, the treatment unit using mass transfer has both chemical action and physical action related to it, so it can also be separated from the chemical treatment method and become another treatment method, which is called physical chemistry method.

Third, biological treatment.

1. wastewater treatment method, through the metabolism of microorganisms, converts organic pollutants in solutions, colloids and fine suspended solids into stable and harmless substances.

2. According to different microorganisms, biological treatment can be divided into aerobic biological treatment and anaerobic biological treatment.

3. Aerobic biological treatment is widely used in wastewater biological treatment. Traditionally, aerobic biological treatment is divided into activated sludge process and biofilm process.

4. Activated sludge process itself is a kind of treatment unit, which has many operation modes. The treatment equipment of biofilm process includes biological filter, biological turntable, biological contact oxidation tank and biological fluidized bed.