Sewage Treatment Process
Wastewater treatment process is to economic municipal sewage and industrial waste water, rational, scientific and effective process method.
Modern wastewater treatment technology, according to the degree of processing can be divided into primary, secondary and tertiary treatment.
Primary treatment, mainly to remove wastewater solids in suspension pollutants, most physical treatment method requires only completed primary treatment. After primary treatment of sewage, BOD removal is generally about 30%, not meet emission standards. Primary treatment belong to a preprocessing secondary treatment.
Secondary treatment, sewage removal was mainly colloidal and dissolved organic contaminants state (BOD, COD substances), the removal rate of up to 90%, so that meet emission standards for organic pollutants.
Tertiary treatment, further treatment of refractory organic matter, nitrogen and phosphorus can lead to eutrophication of water soluble inorganic and so on. The main methods of biological nutrient removal, coagulation sedimentation, sand filtration, activated carbon adsorption, ion exchange and electro-osmosis analysis method.
The whole process is through a coarse grid of raw sewage through the sewage lift pump upgrade later, after grill or sand filters, after entering the grit chamber, after the separation of sewage into the water sand primary sedimentation tank, above the primary treatment (ie physical treatment ), primary sedimentation tank effluent into the biological treatment plant, activated sludge and biofilm, (which activated sludge aeration tank reactor, oxidation ditch, including biofilm biological filter, rotating biological contactors biological contact oxidation and biological fluidized bed), biological treatment plant effluent into the secondary sedimentation tank, secondary sedimentation tank effluent discharged after disinfection or enter tertiary treatment, primary treatment to secondary treatment to this end, three treatment, including biological nitrogen and phosphorus removal, coagulation sedimentation, sand filtration, activated carbon adsorption, ion exchange and electrodialysis. A portion of the secondary settling tank sludge back to the primary sedimentation tank or biological treatment plant, a part of the sludge into the thickener, after entering the digester sludge, after dewatering and drying equipment, sludge is finally use