Research On Stimulation Of Dissimilatory Mn(?) Reduction Bacteria And Removal Of Typical Pharmaceuticals

During the last dacade,pharmaceuticals and personal care products are widely used in pharmacy,industry and stock farming and people's daily life?The pharmaceuticals which are detected frequently in water environment,diverse in characteristics and have poor biodegradation performance attract people a lot?Because the traditional waste water treatments can't remove them effectively,PPCPs come into water body and keep a stable state for a long time and cause water pollution?Although AOPs and membrane can remove PPCPs effectively,their high cost and complicated in process can't achieve largescale application?Dissimilatory metal reduction bacteria are common in soil and sediments?When they reduce Fe(?)/Mn(?)oxide,the organics can be oxidized?The characteristics including abundant biodiversity,ubiquitous and the ability of organic pollutants degradation make the bacteria do a great significance for the ecological restoration?Thus the way that dissimilatory metal reduction bacteria oxidize pharmaceuticals in anaerobic conditions when reducing Fe(?)/Mn(?)oxide can provide a new method to degrade pharmaceuticals?The sediments was collected from Jialing river?CH3COONa and glucose were used as carbon source?The electron acceptors were ?-MnO2 and natural manganese ore powder?In anaerobic conditions,the dissimilatory metal reduction bacteria was stimulated and enriched ? Evaluate the reduction of Mn(?)oxide and the abundance of typical dissimilatory metal reduction bacteria to decide which carbon source and electron acceptors are better?Conclusions list below:(1)When ?MnO2 and glucose were used as electron acceptor and carbon source,the effect is better than CH3 COONa and natural manganese ore powder on stimulation of dissimilatory Mn(?)reduction bacteria?So glucose and ?MnO2 are more suitable for stimulation of bacteria?The 16 SrDNA copy numbers of typical dissimilatory metal reduction bacteria including Geobacter,Bacillus,Clostridium,Anaeromyxobacter per dry sludge were detected through the qPCR ? The result shows that respiratory dissimilatory Mn(?)reducing bacteria work with fermentative dissimilatory Mn(?)reducing bacteria to oxidized glucose when reducing Mn(?)oxide?After enrichment,four sediments NaAC-?Mn,NaAC-Mn,Glu-?Mn,Glu-Mn containing dissimilatory metal reduction bacteria were used to degrade the mixture of 5 typical pharmaceuticals carbamazepine,naproxen,estradiol,diclofenac,ibuprofen?The reaction time was 5 days and the conclusions are drawn as follows:(1)When mixture of 5 pharmaceuticals were used as the only carbon source,4 sediments had no degradation of carbamazepine and ibuprofen?The removal rate of naproxen is from 3.4% to 6.44%?The degradation of estradiol in two sediments——NaAC-?Mn and Glu-?Mn are obvious ?The removal rates are 70.59% and 75.70% respectively when two sediments reduced ?-MnO2?And the degradation rates are 45.97% and 44.98% in other two system ——NaAC-Mn,Glu-Mn when the two sediments reduced natural manganese ore?The removal ratess of diclofenac are 48.10%?31.02%?58.25%?38.79% in NaAC-?Mn,NaAC-Mn,Glu-?Mn,Glu-Mn respectively?(2)Adding CH3 COONa or glucose,carbamazepine and ibuprofen also can't be degraded?The removal rate of naproxen was increased?The degradation of diclofenac was inhibited when adding CH3 COONa or glucose?It has no significant influence to the degradation of estradiol?(3)Control groups with no sediments show that ?-MnO2 and natural manganese ore can't react with carbamazepine,naproxen,ibuprofen?Estradiol and diclofenac can react with MnO2 in some degree?But the degradation rates are less than the groups which are inoculated with bacteria?When the mixture of 5 pharmaceuticals were only carbon source,it was found that biodegradation and oxidation reaction of Mn(?)oxide play the main role in removing estradiol and diclofenac?And the proportion of two reaction are almost the same in removing estradiol ? But in Glu-?Mn sediment,the contribution of biodegradation is more than oxidation reaction in removing diclofenac?The removal process of estradiol and diclofenac conforms to the secondary reaction kinetics in four sediments?...