1. Solid substances floating in wastewater, such as vegetable leaves, peels, minced meat and poultry feathers.
2. Suspended substances in wastewater include oil, protein, starch, colloidal substances, etc.
3. Acid, alkali, salt, sugar, etc. Dissolve in wastewater.
4. Mud, sand and other organic matters entrained in raw materials.
5. Pathogenic bacteria and viruses, etc.
Handan hero introduced some treatment methods of food wastewater;
1, coagulation method
Colloidal substances in water are usually charged. They repel each other and cannot condense to form a stable mixed solution. If the electrolyte with opposite charge is added to the water, the colloid in the wastewater will be neutral and lose its stability, and will condense into large particles and sink under the action of molecular gravity. Commonly used coagulants are polyacrylamide, aluminum sulfate, alum, polyaluminum oxide, ferrous sulfate, ferric chloride and so on. This method has the advantages of simple equipment, easy implementation, popularization and maintenance, but it also has the disadvantages of high operating cost and large sediment volume.
2. Neutralization and neutralization
Neutralization of acidic or alkaline wastewater by chemical method. Alkaline substances such as lime, limestone and dolomite. Add it to acidic wastewater to make food wastewater neutral. Alkaline food wastewater can be neutralized by blowing flue gas containing CO2 or by acid.
3. Redox method
The dissolved organic matter or inorganic matter in wastewater is oxidized or reduced due to the migration of electrons after adding oxidant or reducing agent, and becomes harmless.
4. Electrolysis
Insert the electrode into the waste water. Accepting electrons on the cathode plate will neutralize ionic charges and convert them into neutral atoms. The above comprehensive process leads to anodic oxidation and cathodic reduction.
In addition, the commonly used sewage treatment methods include extraction, stripping, adsorption, electrodialysis, reverse osmosis and so on.
5. Extraction method
A water-insoluble solvent is added to the wastewater to dissolve the solute in the wastewater, and then the solvent is separated by using the specific gravity difference between the solvent and water. Then the solute can be recovered by distillation using the boiling point difference between solvent and solute, and the regenerated solvent can be recycled.
6, blowing off method
Blow air into the wastewater, so that the dissolved gas in the wastewater is blown into the atmosphere. This method can be used for the wastewater treatment of carbon dioxide, H2S and HCN.
7. Adsorption method
Waste water passes through a solid adsorbent, so that organic or inorganic substances dissolved in the waste water are adsorbed on the adsorbent, and the commonly used adsorbent is activated carbon. This method can adsorb toxic substances such as phenol, mercury, chromium and cyanide in wastewater. This method also has excellent decolorization effect. Generally used for advanced treatment of wastewater.
8, electrodialysis method
Electrodialysis is a process in which ions in a solution are transferred through a membrane under the action of an electric field. When wastewater passes through an electrodialyzer composed of anion and cation exchange membranes, anions and cations in wastewater may be separated to achieve the purpose of concentration and treatment.
9, reverse dialysis method
Through a special semi-permeable membrane, under a certain pressure, water molecules are pressed, while solutes are intercepted by the membrane, and wastewater is concentrated. The water passing through the membrane is the water in the treatment process.
Hao Jie Environmental Protection in Handan, a sewage treatment industry, reminds everyone that food production enterprises that treat wastewater need a treatment process with less investment, low operating cost, stable operation, good treatment effect and simple operation and management. When choosing the process, they must consider it in combination with their own actual situation.