The electroplating industry is an important part of the industrial field, however, the electroplating production process produces a large amount of wastewater, which contains heavy metal ions, acids and alkalis and other harmful substances, which pose a serious threat to the environment and ecosystem. Therefore, how to effectively treat electroplating wastewater has become an urgent problem to be solved. The zero-discharge treatment method of electroplating wastewater is a new type of treatment technology, which aims to realize the comprehensive treatment and resource utilization of electroplating wastewater.
The zero discharge treatment method of electroplating wastewater mainly includes the following steps:
Pretreatment. The purpose of pretreatment is to remove large particulate impurities and suspended solids from the wastewater and lay the foundation for subsequent treatment. Commonly used pretreatment methods include sedimentation, filtration, etc. By adding an appropriate amount of coagulant, the large particles of impurities and suspended solids in the wastewater are condensed into flocculents, which are then removed by precipitation or filtration.
Heavy metal ion removal.
Electroplating wastewater contains a large number of heavy metal ions, such as chromium, nickel, copper, etc. These heavy metal ions are harmful to humans and the environment, so they must be removed. Commonly used methods for the removal of heavy metal ions include chemical precipitation, adsorption, ion exchange, etc. By adding an appropriate amount of precipitant or adsorbent, the heavy metal ions are converted into precipitate or adsorbed on solid surfaces, and then removed by precipitation or filtration. Ion exchange is a highly efficient method of removing heavy metal ions by using a special ion exchanger, which adsorbs heavy metal ions in wastewater onto an ion exchanger and then recycles them.
Acid-base neutralization. Electroplating wastewater is usually acidic or alkaline and needs to be neutralized. By adding an appropriate amount of acid or alkali, the pH value of the wastewater can reach a reasonable range to meet the requirements of subsequent treatment. At the same time, acid-base neutralization treatment can also remove some heavy metal ions in wastewater.
Deep processing. The purpose of advanced treatment is to further remove trace harmful substances in wastewater and improve the quality of wastewater. Commonly used advanced treatment methods include activated carbon adsorption, ozone oxidation, membrane filtration, etc. Through these methods, organic matter, ammonia nitrogen, color and other substances in the wastewater can be removed, so that the wastewater can meet the national discharge standards or the requirements of the first utilization.
Reuse and resource utilization.
After the above treatment, the electroplating wastewater can be reused and recycled. Depending on the needs, the wastewater can be treated and utilized differently. For example, it can be used for cooling water inside the factory, toilet flushing water, etc.;It can also be used for agricultural irrigation, garden spraying, etc. after proper treatmentIt can even be used in industrial production after advanced treatment to replace part of the use of fresh water, thus saving water resources.