What should I do if the COD of industrial wastewater cannot be reduced? So

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Characteristics of Industrial Sewage
1. Large emissions, wide pollution range, and complex emission methods.
2. There are various types of pollutants with large fluctuations in concentration.
3. The pollutants have strong toxicity and great harm.
4. There are significant differences in the migration and changes of pollutants after discharge.
5. Recovery is quite difficult.
Methods for reducing COD in industrial wastewater
1. Physical method
Adding flocculants
Usually, flocculants are added to wastewater, and a portion of pollutants are treated using grids or other physical barrier tools to remove some organic matter.
Removal of COD by adsorption method
Activated carbon, macroporous resin, bentonite and other active adsorption materials can be used to adsorb and treat particulate organic matter and chromaticity in wastewater. It can be used as a pre-treatment to reduce the COD that is relatively easy to handle.
2. Electrochemical method for removing COD
The essence of electrochemical treatment of wastewater is to directly or indirectly use electrolysis to remove pollutants from water or turn toxic substances into non-toxic or low toxic substances.
3. Microbial method for removing COD
Biological method is a wastewater treatment method that relies on microbial enzymes to oxidize or reduce organic molecules, destroy their unsaturated bonds and chromophore groups, and achieve the purpose of treatment.
In addition to COD, industrial wastewater also has many components that need to be removed.
Common industrial wastewater treatment methods
1. Multi effect evaporation crystallization technology
In the treatment process of industrial saline wastewater, the industrial saline wastewater enters a low-temperature multi-effect concentration crystallization device, undergoes a concentration crystallization process of 3-6 effect evaporation and condensation, and is separated into desalinated water (which may contain trace amounts of low boiling organic matter) and concentrated slurry waste liquid; Inorganic salts and some organic matter can be separated by crystallization and incinerated into inorganic salt waste residue; The concentrated waste liquid of non crystalline organic matter can be treated by using a drum evaporator to form solid waste residue and incinerate it; Desalinated water can be returned to the production system to replace softened water for utilization.
The low-temperature multi-effect evaporation concentration crystallization system can not only be applied to the concentration and crystallization processes of chemical production, but also to the evaporation concentration crystallization treatment process of industrial saline wastewater.
The multi effect evaporation process only uses steam in the first effect, thus saving the amount of steam required, effectively utilizing the heat in the secondary steam, reducing production costs, and improving economic benefits.
2. Biological method
Biological treatment is currently one of the most commonly used methods for wastewater treatment, with characteristics such as wide application range, strong adaptability, economic efficiency, and harmlessness. In general, there are two commonly used biological methods: traditional activated sludge method and biological contact oxidation method.
1. Traditional activated sludge method
Activated sludge method is an aerobic biological treatment method for sewage, and is currently the most widely used method for treating urban sewage. It can remove soluble and colloidal biodegradable organic matter, suspended solids that can be adsorbed by activated sludge, and other substances from sewage, as well as a portion of phosphorus and nitrogen.
The activated sludge method has a high removal rate and is suitable for treating wastewater with high water quality requirements and relatively stable water quality. But they are not good at adapting to changes in water quality, and oxygen supply cannot be fully utilized; The air supply is evenly distributed along the pool water, resulting in insufficient oxygen in the front section and excess oxygen in the rear section; The aeration structure is huge and covers a large area.
2. Biological contact oxidation method
Biological connection