Paper mill wastewater usually has the characteristics of high concentration of organic matter, deep color, many suspended solids and large fluctuation of pH value, and direct discharge without treatment will not only lead to eutrophication of water bodies, but also cause long-term damage to the ecological environment and affect the safety and stability of water sources.
Paper Mill Wastewater Treatment Technology
Physical Treatment:
Sedimentation method: by adding flocculants, the suspended particles in the wastewater are aggregated into larger flocculents, and then the solid-liquid separation is carried out, such as sedimentation tanks and air flotation tanks.
Filtration method: sand filter, membrane filtration and other methods are used to remove fine suspended solids and some dissolved organic compounds.
Chemical Treatment:
Neutralization regulation: Adjusting the pH value of wastewater to the appropriate range is conducive to the smooth progress of the subsequent treatment process and can neutralize acid and alkali substances.
Chemical flocculation: The addition of coagulants and coagulants can increase the accumulation of fine particles in wastewater, which is convenient for precipitation or filtration.
Redox reaction: For specific toxic and harmful substances, advanced oxidation treatment can be carried out with chemical oxidants (such as Fenton reagent).
Biological Treatment:
Activated sludge method: Under aerobic conditions, the microbial community in the activated sludge breaks down the organic matter in the wastewater.
Biological contact oxidation method: a device filled with a biofilm carrier is used to improve the contact area and degradation efficiency of microorganisms with wastewater.
Anaerobic digestion: For highly concentrated organic wastewater, biogas can be produced by anaerobic fermentation and the organic load can be reduced.
Advanced Processing Technology:
Alkali ** system: Especially for pulping black liquor, the chemical extraction technology of cooking alkali ** is used to reduce the pollution load and realize the reuse of resources.
Electrochemical treatment: Electrocatalytic oxidation technology is used to destroy the complex organic structure in wastewater and convert it into easily degradable substances.
Membrane separation technology: ultrafiltration, reverse osmosis and other membrane treatment methods can further purify wastewater and meet the reuse standard.