Study On Degradation Of Cephalosporins By Aerobic Granular Sludge

PPCPs is a type of new pollutant which closely related to the human life. As a kindof PPCPs,besides the dangers above,antibiotic can produce drug-fast bacteria,havegreat threat on human’s health. Existing studies mainly through physical adsorptionand biodegradation,Adsorption operate is quickly but poor selectivity and desorptionprocess is complex. Due to toxicity caused by antibiotic wastewater,conventionalbiological degradation efficiency of its sewage is not high.Because of its microbialcells immobilized,the aerobic granular sludge is more resilient,able to effectively shieldtoxic substances toxic to itself.In this study,cephalexin as the first-generation cephalosporin is used as arepresentative. Research the training process,physical and chemical properties andbiological characteristics of aerobic granular sludge,which in two SBAR reactors.AndPreliminary analysis of microbial mechanisms on cephalexin removal for a total ofthree aspects.The following is the specific contents and results:(1)the culture of aerobic granular sludge that can degradate cephalosporinCultured aerobic granular sludge is dense spherical or ellipsoida,granular processin the experimental group is slower than the control group.In the experimental groupand the control group the mean diameter were1.56mm and1.69mm, sedimentate rateswere1.3cm/s and1.2cm/s; the remove rate of the experimental group after stabilization(NH4+-N was92±6%, COD was85±5%) slightly lower than in the control group(NH4+-N was95±4%, COD was89±5%).(2)Analysis of physicochemical properties and biological properties on the aerobicgranular sludgeWhen particle size in the range of1mm-1.5mm in two groups,the proportionreached48%in the experimental group, while the control group only15%;in the rangeof1.5mm-2mm, the proportion of32%in the experimental group lower than thecontrol group of52%. Gravity and integrity of the experimental group was94.6and1.012slightly larger than in the control group which were90.7and1.044. EPS in two groups are rich and roughly the same, but the organics’s amount of each of the twogroups are differ. The total amount of EPS in experimental group is53.682mg/gSSwhich less than the control group’s63.995mg/gSS.From the electron micrographs andtotal DNA extracted, the experimental group’s number of species and amount is lessthan the control group.(3) Preliminary analysis of microbial mechanisms on cephalexin removal ofaerobic granular sludge.During the reactor operating, check the cephalexin’s concentration to measure theremoval rate after a cycle ends.Its removal stabilized between93±4%.Cephalexin’sremoval effect can be divided into two parts,wherein the adsorption rate is12%, so thebiodegradation is81±4%approximately.Due to the interference of cephalexin, population diversity of microorganismsin the experimental group had changed,both groups appear to their strengths andendemic species.Experimental group’s specific microorganism is GN02, controlgroup’s specific microorganisms are Euryarchaeota and Crenarchaeota; experimentalgroup’s Advantageous microorganisms are Proteobacteria and Bacteroidetes, theadvantageous microorganisms of the control group are Bacteroidetes, Proteobacteriaand Chloroflexi.