You have chemical wastewater, you should pay attention! Three characteristics make you uncomfortable.

Chemical wastewater is the process wastewater (the main source of high concentration wastewater), cooling water (with a large amount of water), waste gas washing water, equipment and site flushing water discharged by chemical enterprises during the production process. In fact, chemical wastewater is not as simple as it appears on the surface. Originally used in relatively pure water, it has undergone various processes, raw materials, auxiliary materials, and other "torture" to change the original composition of the water and become more complex.

From the perspective of physical properties, the original transparent wastewater has been transformed into wastewater with a certain color, odor, etc; From the perspective of chemical properties, chemical wastewater contains many pollutants, including organic matter, ammonia nitrogen, phosphorus, salt, heavy metals, etc., which are common pollutants in chemical wastewater.

Chemical wastewater has three characteristics: high concentration, complex composition, and poor biodegradability The content of pollutants is relatively high. The wastewater discharged by a certain chemical enterprise includes wastewater with a COD concentration exceeding 100000mg/L and wastewater with a COD concentration exceeding 30000mg/L The reaction raw materials are mostly solvent like substances or cyclic compounds, and the discharged wastewater will carry these substances, making the composition of the combined chemical wastewater more complex; ③ Chemical wastewater contains toxic and harmful substances, and a large amount of biologically difficult to degrade substances, directly manifested as low B/C and poor biodegradability.

The mainstream wastewater treatment methods are combination treatment technologies: physical method+chemical method+biological method.

Industrial wastewater treatment can be divided into physical, chemical, and biological methods. With the characteristics mentioned above, it is difficult for any treatment method to achieve the best results and the treatment cost is too high.

Therefore, we combine multiple methods in the treatment of chemical wastewater, placing them in appropriate locations: pre-treatment, biochemical treatment, and advanced treatment.

The pre-treatment process of chemical wastewater requires chemical methods, which is also a basic operation for treating high concentration organic wastewater in chemical wastewater. The commonly used chemical methods include neutralization, coagulation precipitation, redox, electrolysis, etc. The redox method is an effective chemical reaction that can oxidize or reduce toxic substances, converting them into natural or non-toxic substances, or conducting redox reactions on substances in water, thereby forming a form that can be separated from the water and ultimately achieving the treatment effect.

For example, a certain chemical wastewater adopts the "micro electrolysis+Fenton oxidation method" as its pre-treatment process, achieving a reduction in the COD concentration of the chemical wastewater. The COD is reduced from 30000mg/L to 18000mg/L, and the main biodegradability is also increased from 0.18 to 0.4.

The biochemical treatment process is the key to treating chemical wastewater. In addition to aerobic biological treatment, anaerobic biological treatment is now necessary.

UASB reactor is a type of anaerobic biological treatment and is also widely used in industrial wastewater treatment. It has advantages that other anaerobic biological treatment processes cannot compare, such as achieving sludge granulation, and integrating gas, solid, and liquid, resulting in high wastewater treatment efficiency and efficiency.

The biological contact oxidation method is a type of aerobic biological treatment. Compared with traditional activated sludge and biofilter methods, it has obvious advantages in treatment efficiency, operational stability, engineering investment, and operating costs. Therefore, its application in chemical wastewater has also increased.