Study on Pharmaceutical Wastewater Treatment by Combined Process of Microwave and Biological Contact Oxidation

The COD removal effects from pharmaceutical wastewater with different microwave treatments were studied. The results show that COD removal rate from the wastewater has a similar varied trend with the increase of microwave power at different treatment times, such as 2, 8 and 10 min. The COD removal rate increases with increasing treatment times at different microwave powers, such as 382.5, 434, 459 and 510 W. Decreasing the pH is helpful to remove COD from the wastewater. The combined process of microwave and biological contact oxidation was also used to treat the wastewater. The results show that the best reaction time is 760 min using biological contact oxidation. The COD removal rate is in the range of 10%-15% when the wastewater is treated only by microwave. Similarly, the COD removal rate is also low when the wastewater is treated only by the biological contact oxidation, and COD in the effluent is over 300 mg/L. When the combined techniques are applied to treat the wastewater, the COD removal rate can reach over 95% and COD in the effluent is below 300 mg/L.