Removal Of Fluoroquinolones Antibiotics In Sewage Sludge During Composting Process: Characteristics And Mechanism

Fluoroquinolones(FQs)are very important broad-spectrum antimicrobial.Since FQs have characteristics of bioactivity and bioaccumulative,it may enter the environment in various ways.FQs are detected in sewage sludge in different degrees around the world.Their presence can not only change the community structure of microorganisms,but also enhance the resistance of pathogenic bacteria.Ultimately,it may cause risks of ecosystem security and threatening human health.So that,how to deal with sewage sludge of FQs has become a hot topic for scholars and public attention.In this research,two kinds of typical FQs(norfloxacin,NOR&ofloxacin,OFL)in sewage sludge were studied.The removal characteristics of FQs in sludge and soil can provide theoretical support for the development and optimization the technology of FQs in sludge and soil.Through processes of optimization of the solvent composition and ratio of HPLC mobile phase,based on SPE-HPLC-FLD establish examine method of two fluoroquinolnoes in sewage sludge samples.Show a linear relationship of NOR and OFL within the concentration range of 0.1~10 mg/L and R~2 are both more than 0.999.The ideal recovery rate are70.67~82.98%and 76.40~94.44%,and the detection limit are 10?g/L and 100?g/L respectively.Through examining the samples from 4 sewage treatment plants in Guilin,investigated the concentration condition of 5 typical FQs in Guilin wastewater treatment system.Compare the concentrations of the antibiotics in the sludge during rainy season and dry season,as well as analysis the FQs using condition by Guilin residents.The results show that concentrations of OFL?NOR?CIP?LOM and FLE antibiotics in Guilin sewage sludge are 317.28~1460.66?g/kg?595.57~1180.51?g/kg?61.73~496.83?g/kg?1.29~13.99?g/kg and 8.01~159.48?g/kg respectively.In view of the fact that composting can rapidly reduce the concentration of FQs in sewage sludge,the sludge is treated by three kinds of aerobic composting methods(natural stacking,ventilated static stacking and ventilation-temperature anti-temperature control)to select the best composting process to remove the effect,and to find the FQs removal rate fastest stage.In this study,60-L experiments were run for 30d to investigate the concentration of FQs.In this study,calculate the removal of FQs from sludge by different composting processes and the removal efficiency of FQs.The results showed that ventilation-temperature anti-temperature control is the most appropriate composting method during 30 d.Its removal rate of NOR and OFL are 95%and 91%.The temperature raising period and high temperature period are the main removal stages of the two FQs,removal rate of NOR and OFL are 43%?38%and 46%?24%respectively.Get composting samples from three composting stages respectively.Add FQs to make sure the FQs concentration in the material at 5.0 mg/kg(dry material),the FQs removal experiment was carried out under the corresponding composting temperature.And the experiment lasted 56 days.The result show that,during temperature raising period,the main removal stage of NOR and OFL are biodegradation and adsorption,removal rate are 40.08%and 21.96%respectively.During high temperature period,the main removal stage of NOR and OFL is biodegradation,removal rate are 31.37%and 26.36%respectively.During temperature raising period,the main removal stage of NOR and OFL are adsorption and volatile,removal rate are 16.06%and 9.97%respectively.