Process and principle of ink wastewater treatment阅读：6324 更新时间：2019-10-16 15:23 Source: Environmental Protection Machinery Co., Ltd. Longxin reading: 6324 Updated: 2019-10-16 15:23
The ink wastewater treatment equipment has a wide range of applications, mainly used in the following areas: dyes, printing and dyeing wastewater, coking wastewater, and petroleum processing wastewater. While the above wastewater is being decolorized, the BOD.COD value of the treated water is significantly increased. Petroleum wastewater. Leather wastewater, papermaking wastewater, wood processing wastewater. The BOD and COD values of the above-mentioned wastewater treatment are greatly improved. Electroplating wastewater. The main pollution components in the ink wastewater are cyclic organics (colorants) with colored groups, acrylic water-soluble resins (color carriers), large molecular weight alcohol groups or phenyl dispersants.
During the production and application of water-based inks, a certain amount of wastewater will be generated due to equipment cleaning. The ever-changing color of water-based inks causes the chemical composition of its wastewater to be quite complicated. It has the characteristics of high COD, high chroma, and is difficult to biodegrade. Once entering the water body, it will cause serious pollution to the water environment. The wastewater treatment process is closely related to the type and characteristics of water-based inks.
[Characteristics of ink wastewater]
High density and strong tinting power
During the ink production process, high-concentration waste water is discharged. In general, the chemical oxygen consumption of waste water is greater than 20 g / L, and in severe cases, it exceeds 100 g / L. Due to the strong tinting power of the ink, the color of its production wastewater is extremely high, which can reach more than 100,000 times.
Great difference in water quality
Due to the different ink types, the wastewater water quality will also vary greatly. In addition, the binders, auxiliaries and pigments of different types of inks may all have certain differences, so the differences in discharged wastewater are large. In addition, in different process sections, the amount and quality of wastewater discharged from ink production will also differ.
[Complex composition of ink wastewater]
The main pollution components in the ink wastewater are cyclic organics (colorants) with colored groups, acrylic series of water-soluble resins (coloring agents), large molecular weight alcohol groups or phenyl dispersants. The water-soluble resin in the water is the main component of the wastewater CODcr, accounting for more than four-fifths. There are various types of pigments in ink wastewater, including both organic and inorganic pigments; organic pigments include phthalocyanine pigments, lake pigments, azo pigments, nitroso pigments, heterocyclic pigments, and reducing pigments; inorganic pigments include carbons , Salt and oxide.
[Ink wastewater treatment equipment process]
Electrooxidation process principle
Electro-oxidation methods have been used to remove organic pollutants in wastewater. The reason is that electro-catalytic methods have a good effect on the treatment of difficult-to-degrade organic compounds. As an intermediate product, deep oxidative decomposition of pollutants is achieved.
Electro-oxidation technology, as an environment-friendly technology, has been valued and has a broad application prospect in water treatment because of its advantages such as strong ability to treat pollutants in wastewater, small equipment size, and no secondary pollution. The advantages of electro-oxidation in the treatment of water-based ink wastewater are:
①Electro-oxidation method has low energy consumption and mild reaction conditions. The reaction conditions can be at a lower temperature, and the loss of capacity caused by side reactions can be reduced by controlling the reaction conditions-the reaction conditions are low and the electricity cost is small;
②Electro-oxidation method has little pollution. The treatment of pollutants is mainly through the electron transfer reaction. No other reagents need to be added to avoid pollution caused by the addition of reagents. At the same time, the selectivity of the reaction is high. The free radicals generated by electrolysis can directly react with organic pollutants and degrade into simple low-molecular organic and inorganic substances. There is less secondary pollution-almost no reagents are added during the process, and secondary pollution is not introduced. Clean and efficient
③ The electric oxidation method has high current efficiency and high pollutant removal rate. Iron chip micro-electrolysis process
After the pH of the raw water is adjusted, a sedimentation pretreatment is obtained. The effluent is neutralized and precipitated by micro-electrolysis and lime milk. Through the static and dynamic tests on the main process parameters of micro-electrolysis: pH, amount of coke, iron scrap, and reaction time, the best process conditions for micro-electrolysis are obtained. Raw water undergoes two stages of sedimentation pretreatment and iron chip micro-electrolysis, with high CODCr and chroma removal rates.
【Coagulation air flotation-contact oxidation combined process】
The coagulation air flotation-contact oxidation combined process can be used to comprehensively treat water-based printing ink wastewater, canteen sewage, and domestic sewage to achieve better results. The ink wastewater is coagulated and air-floated after the large suspended matter is separated. After solid-liquid separation, it is mixed with canteen sewage and domestic sewage. After anaerobic adjustment, it is oxidized and aerated by secondary biological contact, and then passed through flocculant alkaline chlorine Aluminium and polyacrylamide float the wastewater after forming alum blooms; after adjusting by anaerobic pretreatment, secondary biological contact oxidation treatment is performed. This process combination has the characteristics of stable treatment effect and impact resistance. Due to the mixing of domestic sewage, the biodegradability of mixed wastewater is improved, and the secondary biological contact oxidation is more conducive to the change of pollutant load, impact resistance, and easy to operate and adjust.