Efficiency Of Bio-electrochemical System On Treating Cephalosporins Antibiotics And Microbial Community Succession Analysis

At present,antibiotic residues have been detected in many areas of the surface water,some microorganisms have generated resistance or even turned into super bacteria.In order to prevent further expansion of bacterial resistance,seeking efficient techniques of antibiotics removal and mastering the changing trend of bacterial resistance are the main directions of water treatment researchers.In this paper,bio-electrochemical system(BES)was used to treat antibiotic wastewater while sequencing batch biofilm reactor(SBBR)was used as a control to explore the effect of bioreactor removal and bio-community succession.The conclusions are as follows:1.The experimental sludge was obtained after 30 days culturing in the SBR reactor.The quality of effluent was good,and the main biological form was coccus,with a single structure.2.The SBBR and BES reactors were filled with modified polypropylene-magnetic materials where biofilm cultured.The reactor cycle was 8 hours.The influent nutrient solution COD was 800 mg/L,the ammonia nitrogen was 40 mg/L,the pH was 6.5-7.5,and the temperature was 18-25 ?.The BES reactor was cultured at a constant voltage of 1.8 V.When biofilm was cultured,the main biofacies in the SBBR reactor were filamentous bacteria and cocci,while the BES reactor were mainly filamentous bacteria,cocci,and bacilli.3.Five cephalosporin antibiotics were selected to acclimate activated sludge in SBBR and BES reactors for a total of 100 days.At the end of acclimation,the removal rates of antibiotics in the SBBR reactor for ceftazidime,ceftriaxone,cefdinir,cefixime,cefepime,were 37.2%,74.1%,82.4%,63.1%,80.2%,respectively.The removal rates for these antibiotics in the BES reactor were 65.7%,94.1%,91.5%,84.1%,and 91.7%,respectively.The efficiency of antibiotics in BES reactor was significantly better than that of SBBR.4.During the acclimation process,the filamentous bacteria in the SBBR reactor served as the biofilm skeleton,which were arranged closely that make biofilm structure more stable.Other microorganisms bound more closely to filamentous bacteria,thus constituted a good biological treatment system.Despite the characteristics of the SBBR microorganisms,microorganisms in the BES reactor exhibited a large number of bacilli that relates electric fields.Nodules appeared in filamentous bacteria,which was related to the stability of filamentous bacteria.The filamentous bacteria on the electrode plate also have the same structure.5.The dominant species for antibiotic removal in the SBBR reactor were Luteococcus,unclassified-f-enterobacteriaceae,Cloac ibacterium,Dysgonomonas,Ottowi,and the dominant species in the BES reactor were Ottowia,unclassified-f-comamonadaceae,and Tahibacte.The abundance of these species increased significantly during the enrichment of antibiotics.6.The new genus norank-o-J30-KF-CM45 appeared in the BES reactor,and the abundances of Ottowia,unclassified-f-comamonadaceae,Tahibacter,norank-f-Veillonellaceae and Nakamurella were significantly higher than those of SBBR.The BES system has good antibiotic degradation with a synergistic effect of these genuses.