| Fleroxacin(FLRX)is a fluoroquinolone antibiotic widely used in clinical practice,Often detected in sewage plants,And FLRX will impact the function and ecological stability of microorganisms in sewage treatment,make the sewage treatment effect worse,and promote the resistance of bacteria in water to enter the human body through the food chain,threatening human health.At present,there are few studies on the effects of FLRX on microbial cell material and activity during biological phosphorus removal.Therefore,in this paper,by adding different concentrations of FLRX(0 ng/L?10 ng/L?100 ng/L?50 ?g/L?500 ?g/L?5 mg/L)in a stable SBR reactor,Using Back scattered Electron Imaging,characteristic X-ray,Raman spectroscopy,synergy interval partial least squares(siPLS)to analyze the mechanism of action of FLRX on the main substances in the microbial intracellular polymer,Zeta potential and Excitation—Emission—Matrix Spectra were used to analyze the mechanism of action of FLRX on the main substances in microbial EPS,the changes of microbial activity were characterized by the measurement of enzyme activity and specific respiratory rate.The main conclusions are as follows:(1)When the influent COD concentration is 180 mg/L,the orthophosphate concentration is 9 mg/L,the pH is 7.5,and the temperature is 25 ?,FLRX of 0 ng/L?10 ng/L?100 ng/L?50 ?g/L?500 ?g/L?5 mg/L were added to 6 SBR reactors.Studies have shown that after the reactor runs stably,as the FLRX concentration increases,the biological phosphorus removal effect gradually decreases.(2)The content of the main substance of the microbial intracellular polymer is determined by a chemical method.The results show that the higher the concentration of FLRX,the lower the content of PHB,polysaccharide and poly-P in the intracellular polymer.The content of main substances in microbial EPS is determined by chemical methods,The results showed that the higher the FLRX concentration,the lower the total EPS concentration and the lower the protein and polysaccharide content.(3)Using Back scattered Electron Imaging,characteristic X-ray,Raman spectroscopy,siPLS algorithm to analyze the mechanism of action of FLRX on microbial intracellular polymers,Studies have shown that: the higher the FLRX concentration,the greater the damage to the phosphorus particles,the lower the content of stored phosphorus,the weaker the biological phosphorus removal function.Raman spectroscopy and its quantitative analysis model further illustrate that as the FLRX concentration increases,the content of the main substance in the intracellular polymer gradually decreases.(4)Using Zeta potential and Excitation—Emission—Matrix Spectra to analyze the mechanism of FLRX on microbial EPS,Studies have shown that the higher the FLRX concentration,the higher the negative charge on the surface of the EPS,the worse the sedimentation and flocculation of activated sludge,thereby weakening the biological phosphorus removal capacity in the reactor.With the increase of FLRX concentration,the peak of tyrosine and tryptophan in EPS under the effect of high concentration of FLRX gradually decreased,the peak of humic acid and fulvic acid gradually increased,and the change under the effect of low concentration of FLRX was not obvious.(5)The measurement of CAT,SOD activity and specific respiration rate in microorganisms found that: The higher the FLRX concentration,the lower the CAT and SOD activities in the microorganism,and the lower the SOUR value,so that the microorganism activity gradually decreases.In this paper,through the biological phosphorus removal process,the main substances and activities of microorganisms under different concentrations of FLRX are studied,and the effects of FLRX on microorganisms are analyzed.It has certain theoretical and reference value to study the influence of fluoroquinolone antibiotics on microorganisms in sewage treatment.Figure [39] Table [22] Reference [107]... |
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