The Application Study On Degradation Of Picric Acid Wastewater By Specially Effective Degrading Bacteria

In this work,a strain was isolated from the soil contaminated by picric acid come from TaoWu chemistry in NanJing.The degradation assays suggested that strain could utilize picric acid as a sole source of carbon,nitrogen and energy.It metabolized 700mg/L picric acid within 35h.This strain identified as a member of Rhodococcus based on biochemical characterization and 16S rRNA sequence,and was named Rhodococcus sp.NJUST16.The influence of temperature,pH,concentration of picric acid,carbon source,nitrogen source and concentration of NaCl are studied in the experiment.The result show that Rhodococcus sp.NJUST16 can grow between 20-35℃,however the optimum temperature for degrading TNP is 30℃;It can grow well by the pH between 7.0-7.5.NaCl is also considered to evaluate the efficiency of TNP removal,and the result shows the efficiency of TNP decomposition of the strain descends gradually with the increase of NaCl concentration in synthetic waste water.Effect of glucose and ammonium sulphate revealed that 0.02% glucose accelerated both the degradation of picric acid and the growth of the cells,while 0.02%ammonium sulphate and urea did not.The best carbon source is glucose,and the next is maltose;The yeast paste and peptone are nutritious,they both can provide nitrogen source and carbon source which accelerated the growth of the cells too.On the basis of the above conclusions,Rhodococcus sp.NJUST16 was applied to the research of the Biological Aerated Filter(BAF.).Two start-up methods were compared.The accession of glucose can enrich the bacteria in the BAF too.The system can nitrify the nitrite to nitrate.The BAF has a high degradation value.It can degradate the synthetic waste water which concent 700-750 mg/L TNP.The average COD load is 1.4136kg/m~3d,and the removal rate of COD achieved 76.39%.