Using ozonation-hydrolysis acidification to the pharmaceutical tail wastewater pretreatment

In order to solve the problems of poor biodegradability and high concentrations of non-biodegradable substances from pharmaceutical wastewater after preliminary treatment, the organic components of the tail water (effluent from the preliminary treatment devises of the pharmaceutical industry wastewater treatment station) were analyzed and the method of ozonation-hydrolysis acidification was used to treat tail water from the pharmaceutical factory. The ozone dosage, the reaction time and the changes of biodegradability were studied. The results measured by GC-MS showed that there were 51 types of organic substances in tail water which reduce the biodegradability. The results of the tests showed that 30 mg/L of ozone and 60-minutes of oxidation time were suitable conditions. In the ozonation–hydrolysis acidification process the COD removal rate ranged from 20% to 50%. The test results showed that the ozonation-hydrolysis acidification method could effectively improve the biodegradability of wastewater and provide the foundation for the follow treatment in urban sewage treatment plant using biological methods.