Effect Of Fluoroquinolones To The Performance And Microbial Community Of Constructed Wetland

Antibiotics,an emerging contaminants able to inducing antibiotic resistance genes,has been widely detected and it has caught great attention due to its higher environmental risks.Fluoroquinolones,a widely used type of antibiotics,has been detected in various environment with high detection rate and concentration and it showed excellent inhibition to gram-positive and gram-negative bacteria.Hence,its potential influence to biological wastewater treatment system has attached much attention.In this study,multiple FQs were added to the influent of constructed wetland to investigate the effluent quality changes and potential shift of microbial community and interactions among various microorganisms.Results indicated that low concentration FQs has no effect on ammonia removal while purification capacity for COD and TP were negatively affected and recovery for effluent COD and TP concentration could be observed as time went by.High concentration FQs for short period did not show great influence to the effluent COD,ammonia and TP while effluent nitrate concentration increased evidently.Meanwhile,the respiration and nitrification were inhibited by the FQs.In addition,after adding low concentration FQs for two months,higher diversity was observed for microbial community within constructed wetland accompanied by composition and structure shift.On phylum level,the relative abundance of Proteobacteria,Actinobacteria,Saccharibacteria significantly decreased while Firmicutes,Bacteroidetes,Planctomycetes and Spirochaetae increased significantly.Among them,Proteobacteria and Firmicutes owning the maximal changes,which decreased from 44.26%to 35.92%and increased from 4.29%to 10.51%respectively.On genus level,88.24%of the genra,relative abundance higher than 1%,showed significant changes while nitrogen,phosphorus and sulfur circle related genra were all affected to varying degrees.Additionally,increased network complexicity,modularity and microbial interactions were obtained for the molecular ecological network of constructed wetland.However,networks related to various species showed distinct trend.In summary,FQs have an evident influence on the performance and microbial community of constructed wetland.This study provided an reference to the stable operation of constructed wetland technology with the presence of FQs.