Zero discharge treatment technology for electroplating wastewater

In the development process of the traditional electroplating industry, electroplating production and electroplating wastewater treatment are usually distinguished. In actual production processes, heavy production and light treatment often occur, which can lead to a large amount of wastewater generated in electroplating production and cause serious pollution to the production environment. From the development of China's electroplating industry, extensive electroplating operations will cause serious damage to the ecological environment. Not only will there be no rapid treatment of wastewater, but it will also consume metals, water, energy, etc. This will cause serious resource waste, which is inconsistent with the sustainable development of the entire society. It can be seen that the lagging phenomenon of the electroplating industry needs to be changed. The application of zero emission technology in electroplating wastewater treatment is a scientific and ecological technology. Applying it can change the unreasonable phenomenon of electroplating industry wastewater treatment at present, gradually achieve zero pollution discharge, and improve the ecological environment.

1The generation of electroplating wastewater

Electroplating wastewater mainly comes from industrial production. If electroplating technology is adopted during industrial production, a large amount of electroplating wastewater will be generated. In actual production, whether pre-treatment or post-treatment is adopted, a large amount of electroplating wastewater will be generated during the production process, which will damage the ecological environment and reduce people's quality of life. Electroplating wastewater mainly comes from the rinsing process of plated parts, which can generate wastewater that accounts for about 80% of the weight of electroplating wastewater. Moreover, electroplating wastewater contains a large amount of various types of harmful substances, and a large amount of liquid will also adhere to the surface of the plated parts. In addition, some decorative or protective products can generate a large amount of electroplating wastewater and high concentrations of pollutants during filtration. At the same time, the generation of electroplating wastewater is directly related to the inadequate management of industrial production workshops. Some electroplating workshops in factories may experience various adverse phenomena such as wastewater "running, emitting, dripping, and leaking" during production operations. After these problems occur, relevant personnel did not take reasonable measures to treat them in a timely manner, but instead treated electroplating wastewater together with ordinary wastewater. This can lead to electroplating wastewater being discharged without reasonable treatment, causing serious damage to the ecological environment.

2Application of zero discharge technology in electroplating wastewater treatment

(1) Application of membrane separation technology

In the late 20th century, the reverse osmosis method was applied to the treatment of electroplating wastewater, and relevant personnel also strengthened their exploration of the application of this technology, mainly through the use of intermediate concentration or desalination devices to achieve the recovery of water and other substances. During the treatment of electroplating wastewater, the reverse osmosis method is reasonably applied in the treatment of galvanized, chromium, nickel rinse water and mixed heavy metal wastewater. The application principle of reverse osmosis desalination is to treat sewage, allowing the treated sewage to withstand pressure beyond natural infiltration, thereby forming opposite osmotic forces. By applying the membrane, water molecules in the sewage are pressed onto the other side of the membrane, forming pure water and removing salt substances from the water.

(2) The application of electro adsorption technology

As an advanced wastewater treatment technology, electro adsorption technology is also widely used in electroplating wastewater treatment operations. This technology has low requirements for the water quality of the treated electroplating wastewater in the specific application process. Moreover, in the electroplating wastewater treatment storage cabinet, it has many advantages such as moderate desalination degree, high water production, good stability, easy maintenance, and simple operation. It is a key means of treating electroplating wastewater and desalination. In the actual treatment process, no chemicals need to be added, and secondary pollution will not occur during concentrated discharge. After entering the 21st century, people have strengthened their research on electro adsorption technology, which has developed rapidly. In the process of continuous development, high-quality electro adsorption models have been formed, which can also maximize the potential of electro adsorption modules.

The principle of electro adsorption desalination technology in specific applications is to use raw water to flow between the anode and cathode electrodes. After being electrified, the water quality ions will migrate towards the electrodes with opposite charges. At the same time, they will adsorb on the electrode surface, and the charged ions will accumulate and concentrate on the electrode surface. This will cause the concentration of other electronic substances to continue to decrease, completing the purpose of water hardening and desalination. Regenerating short circuited electrodes allows the previously adsorbed ions to be released from the electrode surface again, ultimately achieving electrode regeneration and completing the treatment of electroplating wastewater.

3The Implementation Approach of Zero Emission Technology in Electroplating Wastewater Treatment

In the process of electroplating wastewater treatment, in order to properly integrate zero discharge technology with the wastewater treatment system, measures should be taken to re treat the electroplating wastewater that has already met the discharge standards and convert it into electroplating process water. In the process of treating electroplating wastewater, pre-treatment systems and reverse osmosis membrane electro adsorption systems are mainly used. During the design of zero discharge electroplating wastewater treatment system, it is necessary to reasonably apply membrane separation technology and electro adsorption technology to ultimately form a zero discharge wastewater treatment system with good performance and meet the requirements, complete the treatment of wastewater, and thus achieve the protection of the ecological environment.

(1) Preprocessing system

The pre-treatment system mainly consists of precision filters, propylene filters, activated carbon filters, etc. The main function of precision filters in the application process is to intercept various suspended solids in sewage, avoiding adverse effects on subsequent treatment of sewage. After the treated water quality reaches the cooling standard, it is transported to the recycling and refrigeration system for reuse, which has good economic benefits. Through this process, the total output of wastewater can be significantly reduced, the oxide content in electroplating wastewater can be reduced, and it can reach the lowest level. Some technologies have become very mature through continuous research in the long-term application process. Throughout the entire treatment process, zero discharge of wastewater can be achieved, maximizing the environmental protection level of related enterprises in the production process. Moreover, it can reduce production costs and improve economic benefits, which can be said to be a win-win situation.

(2) Treating saline wastewater

At present, many industries adopt membrane treatment to treat saline wastewater in a timely manner during the development process. In the specific treatment process, polymer filtration technology is used to separate and treat the salt substances in the wastewater. After treatment, a large part of the salt in electroplating wastewater can be separated. After completing the above treatment, further treatment is carried out using evaporation crystallization method. In the specific treatment process, high temperature is used for evaporation, and many salt substances in the wastewater can reach boiling points, so they can be extracted one by one. According to the different properties of the extracted salt substances, they are classified and stored accordingly. In this process, efficient application of various materials in electroplating wastewater can be achieved. After evaporation treatment, the water is cooled and returned to the cold water system for recycling and reuse. The treatment can further improve the utilization rate of electroplating wastewater and minimize the discharge of various types of harmful substances.

The evaporation and crystallization processes for treating saline wastewater are completed by two independent systems. At present, many enterprises adopt membrane evaporation technology in the treatment of electroplating wastewater, allowing electroplating wastewater to flow into the evaporator and then into the heating chamber. The equipment is refined into different heat exchange tubes, and the vacuum inside the equipment is maintained to form a uniform film inside the tube. The liquid inside the tube can move freely from top to bottom, thereby achieving rapid evaporation of the liquid and concentration. During the crystallization process, the principle of flash evaporation is applied, and various types of salts are recovered through relevant treatments. The condensed water flows back to the original condensation zone, and then cold water is added to continue its application. In this process, it is important for relevant personnel to note that they must ensure that the reflux water quality meets the standard level, apply existing technologies, and treat the water to meet the standards of high-quality recycled water. Finally, the treated water will be used in the cooling system.

(3) Treating sludge and crystalline salts

For the treatment of sludge in electroplating wastewater, during the actual treatment period, the types of sludge are mainly divided into three different types: organic sludge (sludge formed after biochemical treatment of sewage), chemical sludge (sludge produced by pre-treatment and return water softening unit treatment of sewage treatment station), and mother liquor and impurities (sludge formed by thermal crystallization at the end of the treatment process).

In the process of electroplating wastewater treatment, the wastewater treatment system includes not only organic matter treatment equipment, but also other auxiliary equipment for treating salts, such as centrifuges and sludge desiccants. The performance of various types of equipment will directly affect the wastewater treatment situation. Therefore, when selecting equipment, relevant personnel need to conduct a comprehensive inspection of the equipment performance to ensure that the equipment performance can meet the required standards. For equipment with performance problems, it must be replaced in a timely manner to avoid equipment performance problems, which may lead to wastewater treatment not meeting the required standards. The treatment of sludge and crystalline salts should be achieved through the coordination of modern sludge treatment equipment, and the amount of different types of wastewater generated by relevant industries during production can be significantly reduced, ultimately achieving the goal of zero discharge of electroplating wastewater.


During modern industrial production, it is necessary to continuously learn and innovate new technologies, and focus on innovating the equipment used in production operations. Compared to many industrial productions that produce a large amount of harmful substances, the application of zero emission technology can solve the problem of electroplating wastewater. At present, the application and implementation of zero emission technology face significant problems. Therefore, relevant personnel need to continuously research the technology, strengthen innovation, and improve the rationality of the corresponding technology to promote the healthy development of enterprises.

Post time: Apr-28-2024

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