Waste Water Treatment Technology

Classification of Water Pollution Control Engineering

    Separation technology of insoluble pollutants:

   1. Gravity sedimentation: sedimentation tank (horizontal flow, vertical flow, swirling flow, aeration), sedimentation tank (horizontal flow, vertical flow, radial flow, oblique flow);

   2. Coagulation and clarification;

   3. Floating method: oil separation and air flotation;

   4. Others: resistance interception, centrifugal force separation, magnetic force separation

   Biochemical conversion technology of pollutants:

   1. Activated sludge method: SBR, A/O, A/A/O, oxidation ditch, etc

   2. Biofilm method: biological filter, biological rotary table, biological contact oxidation tank, etc

   3. Anaerobic biological treatment methods: anaerobic digestion, hydrolytic acidification tank, UASB, etc

   4. Biological treatment methods under natural conditions: stabilization pond, ecosystem pond, land treatment method

   Chemical conversion technology of pollutants:

   1. Neutralization method: acid-base neutralization

   2. Chemical precipitation method: hydroxide precipitation, ferrite precipitation, other chemical precipitation

   3. Oxidation-reduction method: chemical oxidation method, chemical reduction method, electrochemical method

   4. Chemical physical disinfection method: ozone, ultraviolet ray, chlorine dioxide, chlorine gas, sodium hypochlorite

   Physical and chemical separation technology of dissolved pollutants:

   1. Adsorption method

   2. Ion exchange method

   3. Membrane separation method: diffusion dialysis, electrodialysis, reverse osmosis, ultrafiltration, nanofiltration, microfiltration

   4. Other separation methods: stripping and stripping, extraction, evaporation, crystallization, freezing

   Classification according to common sewage treatment methods

   Physical method: physical or mechanical separation process. Filtration, sedimentation, centrifugation, floatation, etc

   Chemical method: the process of chemical reaction between chemical substances and harmful substances in sewage. Neutralization, oxidation, reduction, decomposition, coagulation, chemical precipitation, etc

   Physicochemical method: the separation process of physical chemistry. Gas stripping, stripping, adsorption, extraction, ion exchange, electrolytic electrodialysis, reverse osmosis, etc

   Biological method: a metabolic process in which microorganisms oxidize and decompose organic matters in sewage. Activated sludge, biological filter, biological rotary table, oxidation pond, anaerobic digestion, etc

   Classification of waste water by chemical methods

   Coagulation

   Add electrolyte into the colloidal turbid liquid to condense the colloidal substances in the water and separate them from the water

   Coagulants include aluminum sulfate, alum, polyaluminum chloride, ferrous sulfate, ferric chloride, etc

Oily wastewater, dyeing wastewater, gas station wastewater, wool washing wastewater, etc

   Neutralization

   Acid-base neutralization, pH up to neutral

   Lime, limestone, dolomite, etc. neutralize acid wastewater, CO2 neutralize alkaline wastewater

   Sulfuric acid plant wastewater is neutralized with lime, printing and dyeing wastewater, etc

   Redox

   Add oxidizing (or reducing) agent to oxidize (or reduce) substances in wastewater into harmless substances

Oxidants include air (O2), bleaching powder, chlorine, ozone, etc

Wastewater containing phenol, cyanide, sulfur chromium, mercury, printing and dyeing, hospital wastewater, etc

   Electrolysis

Insert an electrode plate into the waste water, and after electrification, the charged ions in the waste water become neutral atoms

   Power supply, electrode plate, etc

Chromium-containing and cyanide-containing (electroplating) wastewater, wool textile wastewater

   Extraction

   Put the solvent insoluble in water into the waste water to make the solute in the waste water soluble in this solvent, and then separate the solvent by using the relative density difference between the solvent and water

Extractant: butyl acetate, benzene, N-503 and other equipment include pulse sieve plate tower, centrifugal extractor, etc

   Phenolic wastewater, etc

   Adsorption (including ion exchange)

   Through solid adsorbent, the dissolved organic or inorganic substances in the wastewater will be adsorbed on the adsorbent, and the wastewater will be treated

   Adsorbents include activated carbon, coal cinder, soil, etc

   Adsorption tower

Dyeing and pigment wastewater can also adsorb phenol, mercury, chromium, cyanogen and remove color, odor and odor for advanced treatment.