Electroplating Wastewater Treatment Graduation Design, Electroplating Wastewater Treatment Solution?

Chemical method: The chemical method relies on redox reaction or neutralization and precipitation reaction to decompose toxic and harmful substances into non-toxic and harmless substances, or directly remove heavy metals from wastewater through precipitation or air flotation.

Biological method: Biological treatment is a new technology for treating electroplating wastewater. Some microbial metabolites can change the valence state of heavy metal ions in wastewater, and at the same time, the microbial flora itself has a strong biological flocculation and electrostatic adsorption effect, which can adsorb metal ions, so that heavy metals can enter the bacterial mud cake after solid-liquid separation, so that the wastewater can be discharged or reused up to the standard.

Physicochemical method: Physicochemical method is the use of ion exchange or membrane separation or adsorbents and other methods to remove impurities contained in electroplating wastewater, which is widely used in industry and is usually used in conjunction with other methods.

Electrochemical method: Electrolysis is the use of electrolysis to treat or heavy metals, and is generally used in electroplating wastewater with high content or single. Electrolysis treatment of Cr (VI) is to use iron as electrode, the ferrous ions produced by the continuous dissolution of the iron anode can reduce Cr (VI) to Cr ( ) on the cathode Cr ( ) directly reduced to Cr ( ) Due to the consumption of hydrogen ions in the electrolysis process, the remaining hydroxide ions in the water make the solution change from acidic to alkaline, and generate hydroxide precipitation of chromium and iron to remove chromium.

The electrolysis method can remove a variety of metal ions at the same time, and has the advantages of good purification effect, less sludge and small footprint, but it consumes more electricity and steel, and has been rarely used.

Characteristics of electroplating wastewater.

The wastewater discharged in electroplating production is characterized by many types and complex water quality. In addition to cyanide-containing wastewater and acid-alkali wastewater, it also contains various heavy metals and various types of surfactants, citric acid, EDTA, thiourea, alkyne glycol, coumarin and other brighteners and additives. If the electroplating wastewater is discharged without treatment, it will pollute drinking water and industrial water, causing great harm to human survival and the ecological environment.

The specific hazards include: 1) the living environment of microorganisms in the water will be destroyed by acid and alkali wastewater, and the pH of the water source and the growth of aquatic animals and plants will also be affected; 2) Cyanide-containing wastewater is very toxic, and under acidic conditions, highly toxic hydrocyanic acid will be generated. At high concentrations, it can cause immediate death.

Even if the concentration is very low, it can cause short-term headaches and irregular heart rate. Neurological sequelae may also occur after cyanide poisoning**.

Electroplating wastewater treatment method.

Electrolysis. The principle of electrolysis is to electrolyze the harmful substances in the wastewater, and the cathodes and cathodes are reduced and oxidized respectively during the electrolysis process to be converted into harmless substances.

Or apply physical action in the process to convert harmless substances into precipitate for further separation and removal. Through electrolytic reactions, heavy metals in electroplating wastewater can also be removed**. At present, most of the heavy metals on the market use electrolysis methods.

The electrolytic method is used to treat electroplating wastewater in small and medium-sized factories. Its main features are that it does not need to add treatment agents, the process is simple, the operation is convenient, the area is small, and the purity is high. If you want to treat a large amount of wastewater, you need to consume a lot of electricity.

In the process of specific treatment, changes in water quantity and quality need to be taken into account.

Heavy metal pollutants are mainly found in electroplating wastewater.

At present, the commonly used methods for heavy metal pollutants are chemical precipitation and chelation precipitation.

Chemical precipitation: Chemical precipitation is a method to convert the dissolved heavy metals in wastewater into water-insoluble heavy metal compounds, including neutralization and precipitation and sulfide precipitation.

Chelation precipitation method: heavy metal scavenger M1 is added to make it chelate and precipitate. The method has a good effluent stability and standard effect, wide application conditions, no secondary pollution, low sludge moisture content, sludge is convenient, and the equipment requirements are simple, but the heavy metal scavenger for the treatment of complexed nickel wastewater needs to be broken first, and the precipitation cannot be directly generated.

1. Chemical precipitation method, adding alkali and sulfide to the wastewater containing heavy metals, so that the heavy metal components in the wastewater can be precipitated, so as to easily remove the sediment; 2. Oxidation method, adding oxidant to make the toxic substances in the wastewater into non-toxic or low-toxic substances; 3. Biological method, using ion exchange or membrane separation to remove impurities in wastewater; 4. Electrolysis method, electrolysis can remove a variety of metal ions, and the purification effect is better.

In the electroplating wastewater treatment, the chemical method equipment is simple, the investment is small, and the application is wide, but the sludge is often left for further treatment.

The treatment of electroplating sewage has been widely valued at home and abroad, and a variety of treatment technologies have been developed to eliminate and reduce the discharge of pollutants by turning toxic treatment into non-toxic, harmful into harmless, precious metals, water recycling and other measures.

With the rapid development of the electroplating industry and the increasing requirements of environmental protection, electroplating sewage treatment has begun to enter the stage of cleaner production process, total control and circular economy integration, and resource utilization and closed-circuit circulation are the mainstream directions of development.

Treatment of wastewater or liquid waste from electroplating production.

The wastewater and waste liquid discharged from the electroplating plant contain a large number of metal ions such as: chromium, pickaxe, nickel, cyanide, acid, alkali, and generally contain organic additives.

Some metal ions exist in the form of simple cations, some exist in the form of acid radical anions, and some exist in complex complex ions.

Chemical methods such as neutralization and precipitation, neutralization and coagulation precipitation, oxidation, reduction, barium salt, and ferrite are commonly used in electroplating wastewater treatment.

The chemical method has simple equipment, low investment and wide application, but often leaves sludge that needs to be further treated.

Traditional treatment technology: pH adjustment, dosing coagulation and precipitation, the effluent adopts A-O process, and the hysteresis of dosing leads to large fluctuations in the concentration of heavy metal ions, which affects the activity of the subsequent biochemical system, and it is difficult to achieve stable standards, poor stability and difficult control.

MEB technology: FCM-IV catalytic auto-electrolysis + BAF process greatly improves the biodegradability of wastewater treatment containing heavy metals, ensures stable effluent quality, can meet the standard of Table 3, has good stability and strong operability.