Sewage features:

Pharmaceutical industry belongs to fine chemicals industry,the organic matter discharged in production process mostly is complicated,poisonous,harmful and biological degradation substances.Therefore,it’s difficult to treat. Sewage features are as follows：

(1)Water composition is complicated,by-products content is high,raw materials usually used solvent chemicals or cyclic structure compound,increase the difficulty of wastewater treatment;(2)The pollutants content is high,it’s because of incomplete reaction,and raw materials or solvent medium used in the production flows into wastewater system;(3)Poisonous and harmful material content is high,fine chemicals industry wastewater has lots of organic pollutants which is poisonous and harmful to microorganisms,such as halogen compounds,nitrocompounds,dispersant has sterilization effect or surfactant.etc;（4)Refractory material content is high,B/C is low,and bad hiodegradability;(5)High chroma.

According to the sewage features,pretreatment is the key of wastewater treatment,it usually uses one or more methods combination of coagulation sedimentation,ozone oxidation,catalytic oxidation,MVR,etc.,after pretreatment,using HEIC or UASB reactor combined with aerobic process generally can meet the emission requirements,special waste water can be further using Fenton method and wet oxidation treatment.Effluent achieves:COD_cr≤100mg/l,BOD₅≤20mg/l.