Kitchen wastewater treatment

• Industry: Environmental Protection Industry
• Process: Grate + Air Flotation Oil Removal Tank + Coagulation Sedimentation Tank + Hydrolysis Acidification Tank + Anaerobic Reactor + A/O + MBR
• Treatment Capacity: 300T/D

The following is A detailed description of the combined process of "grid + air flotation oil removal tank + coagulation sedimentation tank + hydrolysis acidification tank + anaerobic reactor + A/O+MBR" for the daily treatment of 300 tons of kitchen wastewater:

1.Grating 

Function: Remove large suspended particles (such as food residues, plastic bags, etc.) from wastewater. 

Principle: Through physical interception, the large impurities are retained by the gaps between the bars (typically 1-5mm). 

2. Air flotation oil removal tank 

Function: Separates oil and fine suspended particles 

Principle: Dissolved air flotation. By pressurizing the dissolved air water, micro-bubbles are released. These bubbles adhere to oil droplets and suspended matter, causing them to float to the surface and form a scum. 

Chemical assistance: A demulsifier may be added to disrupt the structure of emulsified oil. 

3. Coagulation and Sedimentation Tank 

Function: Further remove colloidal substances, fine suspended solids, and some soluble organic matter. 

Coagulation: Add PAC (polyaluminum chloride) or PAM (polyacrylamide), neutralize the charges of colloids to form flocs. 

Settlement: Flocs settle under the influence of gravity (for example, inclined tube sedimentation tanks can enhance efficiency). 

4. Hydrolysis and Acidification Tank 

Function: Decompose large organic molecules into smaller ones, thereby enhancing the biodegradability of wastewater. 

Hydrolysis: Facultative bacteria secrete extracellular enzymes to break down proteins, fats, etc. into amino acids and fatty acids. 

Acidification: Acidifying bacteria convert small molecules into volatile fatty acids (VFAs) and alcohols. 

5. Anaerobic reactor 

Function: Efficiently decomposes organic matter and generates biogas. 

Principle: Hydrolysis acidification → Producing hydrogen and acetic acid → Producing methane 

Sludge bed: Granular sludge provides a high biomass, and the upward flow promotes mass transfer. 

6. A/O Process (Anoxic/Aerobic) 

Function: Remove nitrogen and phosphorus and deeply degrade organic matter. 

Oxygen-deficient zone: Denitrifying bacteria utilize the carbon source in the raw water to reduce NO₃⁻ to N₂. 

Aerobic section: Nitrogen-fixing bacteria oxidize NH₄⁺ to NO₃⁻; Polyphosphate-accumulating organisms absorb excessive phosphorus. 

7. MBR (Membrane Bioreactor) 

Function: Replace the secondary sedimentation tank, enabling efficient separation of sludge and water and disinfection of the effluent. 

Membrane filtration: The hollow fiber membrane traps sludge and microorganisms.