physical law
Physical or mechanical separation process
Filtration, precipitation, centrifugal separation, flotation, etc.
Chemical method
The transformation process of chemical reaction between chemicals added in sewage and harmful substances.
Neutralization, oxidation, reduction, decomposition, coagulation, chemical precipitation, etc.
Physical and chemical methods
Physical and chemical separation process
Gas stripping, stripping, adsorption, extraction, ion exchange, electrolytic electrodialysis, reverse osmosis, etc.
biological method
Metabolic process of microbial oxidative decomposition of organic matter in sewage
Activated sludge, biological filter, biological turntable, oxidation pond, anaerobic digestion, etc.
Common chemical methods for wastewater treatment
coagulate
Electrolyte is added to the colloidal suspension, so that the colloidal substances in water are condensed and separated from water.
Coagulants include aluminum sulfate, alum, polyaluminum chloride, ferrous sulfate, ferric chloride, etc.
Oily wastewater, printing and dyeing wastewater, gas station wastewater, wool washing wastewater, etc.
invalidate
Acid-base neutralization, pH value is neutral.
Lime, limestone and dolomite neutralize acidic wastewater, while CO2 neutralizes alkaline wastewater.
Sulfuric acid plant wastewater is neutralized with lime, printing and dyeing wastewater, etc.
redox
Adding oxidant (or reducing agent) to oxidize (or reduce) the substances in wastewater into harmless substances.
Oxidants include air (O2), bleaching powder, chlorine, ozone, etc.
Wastewater containing phenol, cyanide, sulfur chromium and mercury, printing and dyeing, hospital wastewater, etc.
electrolyse
When the electrode plate is inserted into the wastewater, the charged ions in the wastewater become neutral atoms after being charged.
Power supply, electrode plate, etc.
Wastewater containing chromium and cyanide (electroplating) and wool spinning wastewater
Extract, lineage
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 relative density difference between the solvent and water.
Extractant: butyl acetate, benzene, N-503, etc. The equipment includes pulsed sieve plate tower, centrifugal extractor, etc.
Phenolic wastewater, etc.
Adsorption (including ion exchange)
The 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 passed waste water is treated.
Adsorbent includes activated carbon, coal cinder, soil, etc.
Adsorption tower, regeneration device
Dyeing and pigment wastewater can also adsorb phenol, mercury, chromium and cyanide, and remove color, smell and taste for advanced treatment.