Wastewater treatment process:
I. Separation technology of insoluble pollutants:
1. Gravity settling: sand sedimentation tanks (advection, vertical flow, cyclone, aeration), sedimentation tanks (advection, vertical flow, spoke flow, inclined flow);
2. Coagulation and clarification;
3. Buoyancy floatation method: grease traps, air-float;
4. Other: Resistance retention, centrifugal force separation method, magnetic separation method
Two, the biochemical transformation of pollutants technology:
1, activated sludge method: SBR, A/O, A/A/O, oxidation ditch, etc.
2, biofilm method: biofilter, biological carousel, biological contact oxidation tanks, etc.
3, anaerobic biological treatment: anaerobic digestion, hydrolysis acidification Pond, UASB, etc.
4, biological treatment method under natural conditions: stabilization ponds, ecosystem ponds, land treatment method
Three, the chemical transformation of pollutants technology:
1, neutralization method: acid and alkali neutralization
2, chemical precipitation method: hydroxide precipitation, ferrite precipitation, other chemical precipitation
3, redox method: Pharmaceutical oxidation, pharmaceutical reduction, electrochemical method
4, chemical and physical disinfection: ozone, ultraviolet light, chlorine dioxide, chlorine, sodium hypochlorite
Four, dissolved state pollutants of the physicochemical separation technology:
1, adsorption method
2, ion exchange method
3, membrane separation method: diffusion dialysis, electrodialysis, reverse osmosis, Ultrafiltration, nanofiltration, microfiltration
4, other separation methods: blowing off and gas extraction, extraction, evaporation, crystallization, freezing
Expanded Information:
Modern sewage treatment technology, according to the degree of treatment, can be divided into primary, secondary and tertiary treatment.
Primary treatment, the main removal of sewage in a suspended state of solid pollutants, most of the physical treatment method can only complete the requirements of primary treatment. After primary treatment of sewage, BOD can generally remove about 30%, not up to discharge standards. Primary treatment belongs to the pretreatment of secondary treatment.
Secondary treatment, the main removal of sewage in the colloidal and dissolved state of organic pollutants (BOD, COD substances), the removal rate of up to 90% or more, so that organic pollutants to meet the discharge standards.
Tertiary treatment, further treatment of difficult to degrade organic matter, nitrogen and phosphorus can lead to eutrophication of the water body, such as soluble inorganic substances. The main methods include biological nitrogen and phosphorus removal, coagulation and precipitation, sand filtration, activated carbon adsorption, ion exchange and electro-osmosis analysis.
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