Wastewater type
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Industrial wastewater
B.heavy metal wastewater
Heavy metal wastewater mainly comes from wastewater discharged from mines, smelting, electrolysis, electroplating, pesticides, medicine, paints, pigments and other enterprises. If the heavy metal wastewater is not treated, it will seriously pollute the environment. The types, contents and forms of heavy metals in wastewater treatment vary with different production companies. In addition to heavy metals, it is important in wastewater treatment.
Since heavy metals cannot be decomposed and destroyed, they can only transfer their existence positions and transform their physical and chemical forms to achieve the purpose of removing heavy metals. For example, in a wastewater treatment process, after chemical precipitation treatment, heavy metals in the wastewater are converted from dissolved ion forms into poorly soluble compounds and precipitated from the water to the sludge; after ion exchange treatment, heavy metal ions in the wastewater It is transferred to an ion exchange resin, and after regeneration, it is transferred from the ion exchange resin to the regeneration waste liquid.
Therefore, the principle of wastewater treatment in addition to heavy metals is:
In addition to heavy metal principle one: the most fundamental is to reform the production process. No or less use of heavy metals with high toxicity;
In addition to heavy metal principle 2: It adopts reasonable process flow, scientific management and operation, reduces the amount of heavy metals and the amount of waste water, and minimizes the amount of discharged wastewater. The treatment of heavy metal wastewater should be treated in situ at the place of production, and different other wastewaters should be mixed to avoid complicating the treatment. It should not be discharged directly into urban sewers without removing heavy metal treatment, so as to avoid the expansion of heavy metal pollution.
Wastewater treatment methods for removing heavy metals can generally be divided into two categories:
In addition to heavy metal method one is to convert the heavy metal in the dissolved state into an insoluble metal compound or element, which is removed from the wastewater by precipitation and floating. Applicable methods such as neutralization precipitation method, sulfide precipitation method, floating separation method, electrolytic precipitation (or floating) method, diaphragm electrolysis method and the like;
In addition to heavy metal method 2: the heavy metal in the wastewater is concentrated and separated without changing its chemical form, and the applicable methods include reverse osmosis method, electrodialysis method, evaporation method and ion exchange method. These wastewater treatment methods should be used singly or in combination depending on the quality of the wastewater, the amount of water, and the like.