1, physical treatment: its purpose is to enrich suspended solids (refers to particle size 10? M or more) from an aqueous solution. There are three ways:
① Precipitation separation and flotation separation are carried out by using the specific gravity difference between suspended matter and water.
(2) separating the filter material by filtration.
③ Centrifuge with centrifugal device.
2. Chemical treatment: it is to treat fine suspended particles or colloidal particles (the particle intuition is 0.0 1~ 10? M) There are four ways to chemically treat or make harmless the harmful components in the waste liquid:
① Inorganic coagulants (polyaluminum chloride, aluminum sulfate soil, etc.) are used for coagulation. ) or organic coagulant (polyacrylamide) to promote the coagulation of fine particles and colloidal particles.
(2) Oxidation-reduction method for treating harmful components in waste liquid by using oxidants such as oxygen and ozone or electrolytic oxidation-reduction reaction.
(3) Adsorption method uses active solids such as activated carbon to adsorb harmful components in the waste liquid on the solid surface to achieve the purpose of treatment.
(4) Ion exchange method uses ion exchange resin to carry out ion exchange on ion harmful components in waste liquid to achieve the purpose of treatment.
3. Biological treatment: The purpose of biological treatment is to treat organic matter (such as organic amine, nonionic surfactant, polyol, etc.). ) In the waste liquid that is difficult to be removed by physical and chemical treatment, the representative methods are adding bacteria sludge method and scattered water filter bed method.
The method of adding bacterial sludge is to mix bacterial sludge (microbial proliferator) with waste liquid for aeration, and treat harmful substances (organic substances) in waste liquid through microbial decomposition.
The scattered water filter bed method is to decompose and treat the organic matter in the waste liquid by microorganisms when the waste liquid flows over the surface of the filter material packed bed (filter bed) covered by microorganisms.
Cutting fluid wastewater treatment
4. Combustion treatment: there are direct combustion method and "evaporation concentration method", that is, the waste liquid is evaporated and concentrated before combustion treatment.
Waste liquid treatment of oil-based cutting fluid
Oil-based cutting fluids generally do not stink and deteriorate. The reasons for changing cutting fluid are mainly due to the chemical changes of cutting fluid, the increase of chip mixing, a large amount of leakage of machine tool lubricating oil and the mixing of water. The following measures can be taken:
1. Improve the purification device of oil-based cutting fluid.
2. Regularly clean the chips in the oil-based cutting fluid box.
3. Repair the machine tool to prevent lubricating oil from leaking in.
4. Add cutting fluid additives regularly.
5. Heat to remove water, precipitate and filter, and then add some cutting oil lubrication additives to restore the quality and continue to use.