Electroplating wastewater is one of the important pollution sources that harm the water environment, mainly including wastewater from chromium plating, zinc plating, nickel plating and other processes. Electroplating wastewater is extremely complex, containing a large number of heavy metal ions and organic substances, which have corrosive and toxic effects on water, soil and organisms, and seriously affect human health and ecological conditions. How to effectively treat electroplating wastewater has become one of the important topics in the field of environmental protection in recent years. In this paper, we will introduce several traditional and new electroplating wastewater treatment methods and technologies.
1. Biological treatment
Biological treatment is a method that uses the metabolism of microorganisms to remove organic and some inorganic substances from electroplating wastewater. Typical biological treatment methods include air aeration, Fahrenheit cell, contact oxidation, etc. Among them, the activated sludge method and process flow are relatively mature, and its basic principle is to degrade the organic pollutants in the wastewater by adding specific microbial flora to produce stable sludge, which is then settled or filtered.
Advantages: The biological treatment method has the advantages of economy, high treatment efficiency and maturity, and the treated wastewater can be directly discharged into the environmental water body.
Disadvantages: The stability of water quality must be ensured when biological treatment is carried out, and the sediment must be regularly removed from the aquaculture ponds and filtration devices. In addition, the biological treatment method has certain limitations in the process of treating wastewater containing some heavy metals such as chromium and nickel.
2. Chemical treatment
Chemical treatment methods include precipitation method, ion exchange method, redox method, etc. Among them, adsorption and removal of organics on ion exchange resin is a widely concerned treatment method.
Advantages: chemical treatment method can remove organic substances and heavy metals in wastewater, and has wide applicability.
Disadvantages: The cost of this method is high, the operation requirements are strict, and the use of chemicals will produce some secondary pollution.
3. Electrochemical treatment
Electrochemical treatment is often used when wastewater contains pollutants that are difficult to treat. This method is based on the principle of electrochemistry, which changes the original chemical reaction equation by using the effect of current in the reaction, and polarizes, transfers charge, and generates free radicals for pollutants that are difficult to degrade in water.
Advantages: the electrochemical treatment method does not produce secondary pollution, the treatment effect is stable, and it is effective for wastewater that is difficult to treat.
Disadvantages: The power consumption is high, and the treatment effect will be affected by various factors such as the nature of wastewater, reaction conditions, etc.
1. Membrane separation technology
Membrane separation technology is to use the filtration of special materials to separate wastewater, which can effectively remove organics, heavy metal ions, suspended solids, microorganisms, etc. in wastewater. Different membranes and different separation methods have different application ranges, such as ultrafiltration membrane, reverse osmosis membrane and gas separation membrane.
Advantages: The membrane separation technology does not need to add chemicals, does not produce secondary pollution, and can efficiently remove single or complex pollutants.
Disadvantages: Membrane separation technology is expensive and requires stable working pressure and flow rate.
2. Photochemical oxidation technology
Photochemical oxidation technology is to use ultraviolet and visible light to stimulate the catalyst, produce active oxides, oxidize the harmful substances in the wastewater, and treat the wastewater into low toxic and low pollution water. This technology can effectively remove organics and some inorganic substances, especially some compounds and toxic substances that are difficult to degrade.
Advantages: The waste water treated by this technology can be discharged directly, which is environmentally friendly.
Disadvantages: photochemical oxidation technology requires special pressure and light conditions, and the reaction process is affected by environmental temperature, pH value and other factors.
No matter which electroplating wastewater treatment method is adopted, the nature and treatment system of wastewater must be evaluated first to determine the appropriate treatment scheme. The current treatment technology has been quite mature. New technologies and methods can better improve the efficiency of electroplating wastewater treatment, reduce costs and reduce secondary pollution. With the continuous development of science and technology, there will be more advanced treatment technologies and methods suitable for large amounts of electroplating wastewater.