Ultraviolet disinfection for electroplating wastewater process
There are many kinds of electroplating production processes. Due to different electroplating processes, the wastewater generated is also different. Generally, the wastewater discharged by electroplating enterprises includes acid, alkali and other pre-treatment wastewater, cyanide containing wastewater, copper containing wastewater, nickel containing wastewater, chromium containing wastewater and other heavy metal wastewater. In addition, a variety of electroplating waste liquid are generated.
There are different treatment methods for electroplating wastewater containing different types of pollutants, as follows:
1. Ultraviolet disinfection process of cyanide containing wastewater (i.e. the use process of ultraviolet sterilizer or ultraviolet sterilizer)
At present, the relatively mature technology for treating cyanide containing wastewater is alkaline chlorination. It must be noted that cyanide containing wastewater must be strictly separated from other wastewater to avoid mixing nickel, iron and other metal ions, otherwise it is difficult to treat. The principle of this method is to use chlorine series oxidants to destroy cyanide and remove cyanide from wastewater under alkaline conditions. The treatment process is divided into two stages. The first stage is to oxidize cyanide into cyanate, which is not completely destroyed. It is called incomplete oxidation stage. The second stage is to further oxidize and decompose cyanate into carbon dioxide and water, which is called complete oxidation stage.
Treatment process:
Cyanide containing wastewater → regulating tank → primary cyanide breaking tank → secondary cyanide breaking tank → inclined sedimentation tank → filter tank → callback tank → ultraviolet disinfection equipment (ultraviolet sterilizer or ultraviolet sterilizer) → discharge
The treated cyanide containing wastewater is mixed with the comprehensive electroplating wastewater for treatment.
2. Ultraviolet disinfection process of chromium containing wastewater (i.e. the use process of ultraviolet sterilizer or ultraviolet sterilizer)
The wastewater containing hexavalent chromium is generally treated by chromium reduction method. The principle of this method is to add reducing agents such as ferrous sulfate, sodium sulfite, sodium bisulfite, sulfur dioxide, etc. under acidic conditions to reduce hexavalent chromium into trivalent chromium, and then add sodium hydroxide, calcium hydroxide, lime, etc. to adjust the ph value, so as to generate trivalent chromium hydroxide precipitation and separate from the wastewater. The treatment process is as follows:
Wastewater containing cr6+→ regulating tank → reduction reaction tank → coagulation reaction tank → sedimentation tank → filter → ph callback tank → discharge
3. Disinfection process of comprehensive heavy metal wastewater by ultraviolet ray (i.e. the use process of ultraviolet sterilizer or ultraviolet sterilizer)
Comprehensive heavy metal wastewater is composed of heavy metal wastewater containing non complex substances such as copper, nickel and zinc, as well as acid and alkali pretreatment wastewater. This kind of wastewater treatment method is relatively simple, and generally adopts the process of generating hydroxide precipitation under alkaline conditions for treatment.
The treatment process is as follows:
Comprehensive heavy metal wastewater → regulating tank → fast mixing tank → slow mixing tank → inclined tube sedimentation tank → filtration → ph callback tank → ultraviolet disinfection equipment (ultraviolet sterilizer or ultraviolet sterilizer) → discharge
4. Comprehensive treatment of various electroplating wastewater Ultraviolet disinfection (i.e. the use process of ultraviolet sterilizer or ultraviolet sterilizer) Disinfection process
When a electroplating plant contains a variety of electroplating wastewater, such as cyanide containing wastewater, hexavalent chromium containing wastewater, acid and alkali containing wastewater, heavy metal copper, nickel, zinc and other comprehensive wastewater, the method of wastewater diversion treatment is generally adopted. First, cyanide containing wastewater and chromium containing wastewater shall be separately collected from the production line, and then the cyanide containing wastewater and chromium containing wastewater shall be separately treated according to the above corresponding methods, The treated wastewater is mixed with the comprehensive wastewater for subsequent treatment by coagulation sedimentation method.
The treatment process is as follows:
Cyanide containing wastewater → regulating tank → primary cyanide breaking tank → secondary cyanide breaking tank → comprehensive wastewater tank
Chromium containing wastewater → regulating tank → chromium reduction tank → comprehensive wastewater tank
Integrated wastewater → integrated wastewater tank → fast mixing tank → slow mixing tank → inclined tube sedimentation tank → intermediate tank → filter → ph callback tank → ultraviolet disinfection equipment (ultraviolet sterilizer or ultraviolet sterilizer) → discharge