Chemical industry is an industry that uses oil or natural gas as the main raw material to produce various chemical products, organic chemical raw materials, chemical fibers and fertilizers through different production processes and processing methods. Due to the different raw materials, processes and processing methods used in the production process, the types and characteristics of chemical wastewater are also quite different.
The treatment of chemical wastewater can not only protect the environment from pollution and protect people’s lives, but also improve the reuse rate of water resources in the production system. The reuse of water resources is far greater than the value of water resources. Filtration and purification can effectively realize the secondary utilization of water resources, which is more related to energy regeneration and water recycling, So as to effectively solve the bottleneck problem of water shortage and reuse in chemical production. In addition, strengthening environmental protection supervision and treatment and prevention situation will also increase more competitive advantages for chemical wastewater treatment and chemical enterprise circular economy industry chain, and industry competition will put forward more severe test for chemical enterprise production environmental protection prevention and control management and control scheme.
Analysis on characteristics of chemical industry wastewater
- Chemical wastewater has a large amount of discharge and complex composition, and the reaction materials are usually solvent substances or compounds with ring structure, which increases the difficulty of wastewater treatment.
- The waste water contains a lot of pollutants, mainly due to incomplete reaction of raw materials and the use of a large number of solvents in raw materials or production.
- There are many toxic and harmful substances, such as high concentration of organic matter, high salt content, high chroma, high content of refractory compounds, and many biological refractory substances, which are difficult to control due to poor biodegradability., Inorganic acids, bases and other irritant and corrosive substances. There are many organic pollutants in fine chemical wastewater which are toxic and harmful to microorganisms, such as halogen compounds, nitro compounds, cyanide, phenol, arsenic, mercury, cadmium, lead and other toxic or highly toxic substances, polycyclic aromatic compounds, dispersants or surfactants with bactericidal effect, etc.
Analysis of chemical wastewater treatment technology
At present, chemical industry wastewater treatment methods mainly include reduction method, ecological safety method and whole process control method. These control methods play a very important role in wastewater treatment. The reduction method strictly separates, controls, filters and purifies the pollutants and sewage at the source. The domestic sewage and production wastewater are collected separately, and then the clean water and sewage are separated and controlled at the source. Ecological safety method is mainly to effectively remove toxic and harmful substances in sewage, and reduce the generation of disinfection by-products and excessive residual chlorine in effluent during treatment and whole process control, so as to protect the ecological environment. In order to avoid secondary pollution, the odor, sludge and slurry generated in the process of sewage treatment should be properly disposed.
In addition to considering the environmental protection requirements of the production wastewater treatment, we should strengthen the process control of environmental risk, and take countermeasures and environmental safety strategies from the aspects of process technology, supervision and management and engineering construction.
The sewage treatment process can be roughly divided into three processes according to the treatment steps, physicochemical biochemical physicochemical. It is required by the actual project treatment situation and in line with the actual production. The correct selection of methods is the core part of the sewage treatment system.
Chemical industry wastewater treatment technology
- Physical method
Physical method is a kind of wastewater treatment method to separate and recover suspended pollutants in wastewater by physical action. Physical treatment methods include centrifugal separation, filtration, air flotation and demulsification. The filtration method refers to the interception of impurities in the water through the porous granular filter material layer, mainly to reduce the suspended solids in the water; Air floatation means that air is introduced into the water to produce large bubbles in the water, which can make them adhere to the impurity particles to form a floating body with a smaller specific gravity than water. Under the action of buoyancy, it floats up to the water surface to realize solid-liquid separation; Demulsification is mainly used to treat oily wastewater, destroy the stable emulsion layer on the droplet interface, and separate oil and water. Although the traditional physical method has the advantages of simple process and convenient operation, it is not suitable for the removal of soluble wastewater components and has great limitations.。
- Chemical method
Chemical treatment is a kind of wastewater treatment method to separate and remove dissolved and colloidal pollutants in wastewater or convert them into harmless substances through chemical reaction, which also plays an important role in the advanced treatment of wastewater. The main chemical treatment methods are coagulation, neutralization, chemical precipitation and oxidation-reduction.
- Biological method
The biological treatment of wastewater is the process of transforming the organic matter in wastewater into simple inorganic matter by using the metabolism of microorganisms. In short, it is a method of transforming pollutants by using the life activity process of microorganisms, and finally achieving harmless. This method can be divided into aerobic biological treatment and anaerobic biological treatment according to the types of microorganisms involved.
- Physicochemical method
Physical and chemical treatment methods include iron carbon micro electrolysis, heterogeneous catalytic oxidation, adsorption, ion exchange, electrodialysis, etc.
Micro electrolysis technology is an ideal process for the treatment of high concentration organic wastewater. It can not only greatly reduce COD and chroma, but also greatly improve the biodegradability of wastewater. This technology is to use the “galvanic cell” effect produced by the micro electrolysis filler in the micro electrolysis equipment to treat the wastewater without power supply. When water is supplied, countless “galvanic cells” with potential difference of 1.2V will be formed in the equipment“ The “galvanic cell” uses wastewater as electrolyte, and electrolyzes the wastewater to oxidize and reduce through the current formed by discharge, so as to achieve the purpose of degrading organic pollutants.
Heterogeneous catalytic oxidation technology is a new technology in the field of environment. It mainly uses strong oxidant with hydroxyl radical as the core to oxidize various organic pollutants in the environment rapidly, non selectively and thoroughly. Hydroxyl radical reacts with dissolved organic matter in water to form hydroxyl radical; Under the catalysis of catalyst, hydroxyl radical can oxidize and decompose organic matter in wastewater.
Scope of application: nitrobenzene, nitrophenol, nitrotoluene, phenol, aniline sewage, anisole sewage; Disperse dye, cationic dye and weak acid dye wastewater; Synthetic medicine and pesticide wastewater; Veterinary wastewater; Fine chemical wastewater; Synthetic resin wastewater; Wastewater containing cyanide; Fluorine containing wastewater; Wastewater Containing Anthracene; Coking wastewater and electroplating wastewater, etc.