Wastewater from pharmaceutical industry is a kind of organic matter with complex structure, toxic, harmful and difficult to be degraded by organisms, which causes serious pollution to water body. At the same time, the industrial wastewater is also clear acid and alkaline, and some of the wastewater contains too much salt. These characteristics make pharmaceutical wastewater more difficult to treat in the water treatment industry. Pharmaceutical industrial wastewater mainly includes antibiotic production wastewater, synthetic drug production wastewater, Chinese patent medicine production wastewater, as well as cleaning water and washing wastewater in the production process of various preparations. Its wastewater is characterized by complex composition, high content of organic matter, high toxicity, deep color and high salt content, especially poor biochemical property and intermittent discharge, which is difficult to treat. With the development of China's pharmaceutical industry, pharmaceutical wastewater has gradually become one of the important pollution sources. How to treat this kind of wastewater is a difficult problem of environmental protection.

1. Coagulation sedimentation method

The first choice of physicochemical method is the more economical coagulation sedimentation method. Generally, coagulation treatment can not only effectively reduce the concentration of pollutants, but also improve the biodegradability of wastewater. Coagulants commonly used in pharmaceutical wastewater treatment are: polymeric ferric sulfate, ferric chloride, ferrous salt, polymeric aluminum chloride, polyacrylamide (PAM), etc. The disadvantages of flocculation and sedimentation process are: a large amount of chemical sludge will be produced; the pH value of effluent is low, the salt content is high; the removal rate of ammonia nitrogen is low. Therefore, even if there is a better treatment effect, it should be carefully considered in the selection.

2. Air flotation

Air floatation usually includes aeration, dissolved air floatation, chemical air floatation and electrolytic air floatation. In the treatment of pharmaceutical wastewater, such as gentamicin, oxytetracycline, medicin and so on, chemical air flotation is often used. After the gentamicin wastewater was treated by chemical air flotation, the removal rates of COD and suspended solids were more than 50% and 70% respectively.

3 adsorption method

Adsorption refers to the use of porous solid adsorption of some or several pollutants in wastewater, in order to recover or remove pollutants, so that the wastewater can be purified. In the treatment of pharmaceutical wastewater, coal ash or activated carbon is often used to adsorb and pretreat the wastewater from the production of Chinese patent medicine, mifepristone, diclofenac, lincomycin, paracetamol and vitamin B6.

4 blowing off method

When the concentration of ammonia nitrogen greatly exceeds the allowable concentration of microorganisms, microorganisms are inhibited by NH3-N in the process of biological treatment, so it is difficult to achieve good treatment effect. Ammonia removal is often the key to the effect of wastewater treatment. In the pharmaceutical industry wastewater treatment, blowing off method is often used to reduce the ammonia nitrogen content, such as the ammonia removal of amiodarone wastewater.