1. redox neutralization precipitation method
This method is mostly suitable for organic compounds containing hexavalent chromium and reducing toxic substances and metals. It is mainly used to treat wastewater containing cyanide, phenol and sulfide. The common process is to add oxidant to waste water, and after redox reaction, the highly toxic substances are transformed into low toxic substances, and then they are removed from the reaction system through coagulation and precipitation. The maximum allowable discharge of inorganic substances of C R6+ and C R3+ is 0. 5 mg/l and 3. 0 mg /L。 Chromium-containing waste liquid can be reduced by iron and zinc. Neutralize the precipitate with waste lye, and then convert it into insoluble salt to remove it.
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2. Sulfide precipitation method
This method is suitable for acidic experimental wastewater containing mercury, lead and other metals. Generally, sodium sulfide is added into wastewater to generate water-insoluble metal sulfide, which is then precipitated and separated from Fe (OH) 3 ***.
3. Flocculation precipitation method
Flocculation precipitation method is not only an effective method to treat heavy metals in wastewater from many industrial enterprises, but also a feasible method to treat laboratory wastewater.
Method. This method is suitable for experimental wastewater containing more heavy metals. Adding suitable flocculant can form flocculent precipitation under weak alkaline conditions, effectively remove heavy metal ions in wastewater and reduce the chemical oxygen demand (COD) of wastewater.
4. Activated carbon adsorption method
This method is mostly used to treat a small amount of dissolved organic experimental wastewater that cannot be treated by physical and chemical methods. Organic experimental wastewater contains a lot of waste solvents, experimental residual liquid, organic acids and so on. Its characteristics of high concentration and low emission are very suitable for activated carbon adsorption treatment. The treatment process is to separate the organic phase from the wastewater and then adsorb it with activated carbon. COD removal rate can reach 93%?
5. Incineration
Each processing method has its own specific processing performance, and it is not omnipotent. Incineration is usually suitable for forming liquids, such as emulsions. However, special attention should be paid to avoid secondary pollution caused by toxic gases produced by combustion. For example, organic wastes containing only C, H and O will not cause secondary pollution when burning, while organic wastes containing halogen elements such as N and S will release a variety of harmful gases when burning.
6. How to treat the biological experiment wastewater?
The common treatment methods of biological experiment wastewater are thermal disinfection and chemical disinfection and sterilization. Thermal disinfection and sterilization method is to make the temperature of wastewater reach or exceed the highest limit of the survival temperature of some harmful microorganisms by heating at high temperature, kill bacteria and ensure the safety of wastewater discharge. The principle of chemical disinfection and sterilization is to kill harmful microorganisms in wastewater by using various chemicals. At present, the commonly used disinfection processes are ozone disinfection, chlorine disinfection and alkali disinfection. In practice, the combination of heat and chemical reagents can be used to safely and effectively treat wastewater from biosafety laboratories.