Micro-electrolysis + Fenton treatment of high-concentration chemical wastewater!

The demand for chemical products in daily production and daily life has led to the rapid development of chemical production in my country, and the chemical industry has also led to increasingly serious local environmental problems in my country, especially the large amount of waste water discharge in the chemical industry, resulting in serious water pollution in the rivers surrounding the chemical park. According to research, chemical wastewater mainly comes from: 1) Emerging and dripping during the use of chemical raw materials and products. 2) Flushing wastewater on the floor of the workshop. 3) Equipment cleaning wastewater and wastewater generated from pollutant treatment. 4) Cooling discharge water, etc. According to the analysis of the source of chemical waste water, it can be divided into three types of chemical waste water: organic, inorganic, and organic-inorganic mixed. They have the following common characteristics: 1) Toxic and irritating. Such as halogen compounds, dispersants or surfactants with bactericidal effect, etc. 2) There are many components in wastewater, and a certain amount of by-products and incompletely reacted raw and auxiliary materials and auxiliary agents will be produced in the chemical production process. 3) The content of pollutants is large and the degradation is difficult. Among them, nitro compounds, as one of the main pollutants in chemical wastewater, have the characteristics of being difficult to biodegrade, which brings great difficulty to the subsequent treatment of wastewater. 4) The color changes quickly and the chroma is high. 5) Great changes in water quality and quantity. 6) Ecological restoration and governance are difficult. For waters polluted by chemical wastewater, it is difficult to restore the original system functions, and the cost is high.

Existing high-concentration COD chemical wastewater treatment process

Chemical wastewater treatment technology

Chemical wastewater contains diverse components, and different types of pollutants contained in different chemical wastewaters are not the same. The treatment of chemical wastewater requires a combination of multiple processes to achieve the treatment effect. The existing treatment schemes can be divided into the following categories according to the principles: physical methods and chemistry Methods and biological treatment methods, etc. The process of separating the toxic and harmful substances contained in the chemical wastewater after multi-step treatment, or transforming them into stable and harmless substances is called harmless treatment.

According to the degree of wastewater treatment, the water treatment process can be divided into pre-treatment engineering, biochemical treatment engineering and advanced treatment engineering.

1) The main purpose of the preliminary pretreatment project is to intercept suspended solids, adjust water volume, adjust PH value, etc. It is usually treated by physical and chemical methods, and its facilities include wastewater adjustment tanks, grilles, etc.

2) The biochemical treatment project is the main project of wastewater treatment, and the treatment process selected according to the water quality is also different. The main methods include traditional activated sludge method, oxidation ditch method, AB method, A/O method, A2/0 method, SBR method Wait.

3) Advanced treatment engineering is an advanced treatment measure after preliminary treatment and moderate biochemical treatment. After the effluent reaches the specified requirements, it can be discharged. Activated carbon adsorption device, membrane separation method, advanced oxidation method, photochemical catalytic oxidation method, electrochemical oxidation method, Ultrasonic radiation degradation method, radiation method and other methods are used to ensure that the effluent quality is stable and meets the standard.

In practical application, these three stages are unified and relatively independent as a whole, and crossover phenomenon may also occur in some occasions. On the other hand, since the comprehensive treatment cost of the biochemical treatment stage is significantly lower than that of the advanced treatment stage, and the treatment effect of the advanced treatment stage is easily disturbed by water quality factors, it is generally required to remove pollutants as much as possible in the biochemical treatment stage.

Overview of High COD Chemical Wastewater Treatment Technology

The color of high-COD chemical wastewater is much deeper than general industrial wastewater. It has the characteristics of poor biodegradability, strong corrosiveness, and difficult treatment after pollution. The companies that can produce high-COD chemical wastewater mainly include pharmaceutical companies, fine chemical companies, Refining and chemical companies, pesticide production companies, etc., after the chemical wastewater of these companies is discharged into the water body, there are many toxic substances and the water quality changes greatly, resulting in serious ecological damage. The toxic and harmful substances in the chemical wastewater can enter the organism through various methods and be Accumulation in the body, ranging from chronic poisoning to severe brain damage and other diseases.

According to research, the treatment of chemical wastewater with high COD content mainly includes advanced oxidation method, biochemical method, photocatalysis method, adsorption method, incineration method, etc.

In summary, choosing a suitable high-COD chemical wastewater treatment process can not only enable enterprises to meet discharge standards, but also promote the coordinated development of the regional environment and economy.

Micro-electrolysis + Fenton system to treat chemical wastewater

High-COD chemical wastewater contains more difficult-to-biodegradable pollutants. The micro-electrolysis Fenton system is used for pretreatment to degrade and destroy macromolecular organics, thereby reducing its toxicity and improving biodegradability. Its principle of action is as follows.

Microelectrolysis

The reaction mechanism of iron-carbon microelectrolysis is to place iron filings (the main components are iron and carbon) in acid wastewater. Due to the 1.2V potential difference between Fe and C, a large number of micro-battery systems are formed in the wastewater. The reaction product has the function of adsorption and filtration to reduce and reduce the pollutants in the wastewater, that is, the anode is oxidized to produce Fe and Fe3+ in the process of microelectrolysis, and Fe3+ hydrolyzes and precipitates to form a flocculant with adsorption formation, and the cathode produces [H] And [O] continue to undergo oxidation reaction to degrade macromolecular organics in wastewater and improve the biodegradability of wastewater. During the reaction process, the cathode generates OH, which increases the PH value of the treated wastewater.

Fenton reaction

After the iron-carbon micro-electrolysis reaction, H2O2, Fe2+ and H2O2 are added to form the Fenton reagent oxidation system. Since H2O2 is catalyzed and decomposed by Fe2+ to produce OH˙ (hydroxyl radicals), the oxidation electrode potential is 2.8V, which makes the Fenton reagent extremely strong The oxidizing ability can oxidatively decompose the difficult-to-degrade organic matter in the sewage into small molecular organic matter and inorganic matter, and realize the degradation of organic matter.

Neutralize precipitation

By adjusting the pH value of the acidic effluent of the micro-electrolysis Fenton system to about 8, and adding a coagulant, the removal of suspended solids and other precipitates in the wastewater can be achieved. When processing chemical wastewater, the neutralization and precipitation process can independently remove pollutants in the wastewater and can also be used as an intermediate project to improve the wastewater treatment effect.

The chemical park inevitably produces high COD chemical wastewater. Aiming at the "three highs" characteristics of chemical wastewater with high COD, high chroma and high toxicity, the high COD is effectively reduced through the "micro-electrolysis Fenton oxidation system + neutralization precipitation" treatment The impact of wastewater on the park's biochemical treatment system ensures the stable operation of the park's sewage treatment plant.