Pretreatment Research Of Low Biodegradability Benorylate Medicine Wastewater With Chlorine Dioxide

The wastewater produced by some plants of Di Ao Group Chengdu Pharmaceutical Co., LTD is typical high concentration organic wastewater. The COD_cr in the wastewater is over 120000 mg/L, and the value of BOD₅/COD_cr is 0.12or so(it is commonly recognized that 0.3 is of acceptable biodegradability). It is a difficult problem to be solved to treat the high concentrated industrial wastewater in the field of environmental protection techniques in our country. The objective of this paper is to improve the efficiency of biodegradability process in treating Benorylate medicine wastewater by the chlorine dioxide pretreatment. The oxidation law of that the Benorylate medicine wastewater is treated by chlorine dioxide has been discovered. The experimental researches provide not only the basic data for the further studies of chlorine dioxide disposing Benorylate medicine wastewater, but also the new idea of treating the wastewater of high concentration and low biodegradability.The contaminations of medicine wastewater are oxidated and decomposed by using stabilized chlorine dioxide solution as an oxidant. Taking the Chemical Oxygen Demand (COD_cr) and the Bio-Chemical Oxygen Demand (BOD5) of the wastewater as the index of oxidation efficiency, Taking the value of BOD₅/COD_cr of the wastewater as the index of biodegradability. The influences of the volume of stabilized chlorine dioxide solution and reaction time on the disposal effect of the medicine wastewater are investigated under the condition of the normal temperature (291²98K) and normal atmospheric pressure (1.013 ×10⁵Pa).By the experiment of chlorine dioxide pretreatment, the reaction of chlorine dioxide solution and the wastewater is complete in 75 min. Along with the increment of chlorine dioxide solution, the removal rate of BOD5and CODcr are improved. And when the volume of the wastewater is 50 timesof the volume of chlorine dioxide solution, the figures reach the maximum, 41.60% x 9.46% and 0.68. The value of BOD5/COD a shows that thebiodegradability of wastewater is improved. The pretreated wastewater and unpretreated wastewater are taken into UASB reactors. Comparing the indexes of the two wastewater after anaerobic reaction, we can find that the removal rate of BOD5 and CODcr of the pretreated wastewater arehigher than those of unpretreated wastewater. That validate that the chlorine dioxide pretreatment impoves the Biodegradability of the medicine wastewater. By the experiment, the safe range of chlorine dioxide solution is also discovered.