(1) Physical method: It uses physical effects to separate suspended solids or emulsions in wastewater, and can remove COD in wastewater. Common methods include grilling, screening, centrifugation, clarification, filtration, oil separation and other methods.
(2) Chemical method: It uses chemical reactions to remove dissolved substances or colloidal substances in wastewater, and can remove COD in wastewater. Common methods include neutralization, precipitation, redox, catalytic oxidation, photocatalytic oxidation, micro-electrolysis, electrolytic flocculation, incineration and other methods.
(3) Physical and chemical method: It uses physical and chemical effects to remove dissolved substances or colloidal substances in wastewater. Can remove COD from wastewater. Common methods include grilling, screening, centrifugation, clarification, filtration, oil separation and other methods.
(4) Biological treatment method: It uses microbial metabolism to convert organic pollutants and inorganic microbial nutrients in wastewater into stable and harmless substances. Common ones include activated sludge method, biofilm method, anaerobic biological digestion method, stabilization pond and wetland treatment, etc.