垂直潜流人工湿地对水产养殖尾水中抗生素和氮磷的去除及其影响因素

Analysis of influence factors on antibiotics and nutrients removal from aquaculture wastewater by vertical flow constructed wetlands

针对养殖尾水中氮磷和抗生素污染问题,构建了3种不同条件的上行垂直潜流人工湿地小试系统,分析了养殖尾水中4种典型抗生素(氧氟沙星、磺胺甲恶唑、氟苯尼考和土霉素)的去除效率及其影响因素,探讨了抗生素对营养盐去除的潜在影响。结果表明:在春季和夏季,3种不同条件的上行垂直潜流人工湿地系统对氟苯尼考、土霉素、氧氟沙星和磺胺甲恶唑的去除率分别为25.61%~53.66%和15.10%~37.93%、94.82%~97.16%和93.96%~94.87%、93.53%~94.27%和85.17%~86.57%、10.48%~57.54%和29.84%~62.36%。添加生物炭可以显著提高湿地系统对磺胺甲恶唑和氟苯尼考的去除率,与CW1和CW2相比,CW3对磺胺甲恶唑的去除率平均分别提高了39.79%和33.92%;对氟苯尼考的去除率平均分别提高了25.45%和22.61%。在抗生素暴露条件下,春季,系统对总氮、总磷、氨氮和硝态氮平均去除率分别下降了11.69%、17.53%、10.04%和4.07%;夏季,总磷和氨氮的平均去除率分别下降了19.41%和5.53%,而总氮和硝态氮的平均去除率分别提高了11.67%和10.42%。以上研究结果可为进一步改进人工湿地系统设计参数,提高污染物去除效率提供参考依据。

Constructed wetlands(CWs)are widely used for removal of pollutants in aquaculture wastewater due to its advantages of efficient,economical and environment-friendly features.Aiming at the problems of antibiotics and nutrients pollution in aquaculture wastewater,three test-batch vertical flow constructed wetlands(VFCW)with different substrates or plant conditions were constructed to investigate the factors affecting the removal of four typical antibiotics and nutrients from aquaculture wastewater,then the potential effect of antibiotics on the nutrient removal was further studied.The results showed that the removal rates of florfenicol,oxytetracycline,ofloxacin and sulfamethoxazole were 25.61%~53.66%,94.82%~97.16%,93.53%~94.27%and 10.48%~57.54%in spring,then 15.10%~37.93%,93.96%~94.87%,85.17%~86.57%and 29.84%~62.36%in summer,respectively.Addition of biochar as substrate could significantly increase the removal rates of sulfamethoxazole and florfenicol by VFCW.Compared with CW1(VFCW with no biochar and plant)and CW2(VFCW with no biochar),the average increase ratios of sulfamethoxazole removal rate by CW3(VFCW with biochar and plant)were 39.79%and 33.92%,respectively;the average increase ratios of florfenicol were 25.45%and 22.61%,respectively.In spring,after 3 days-exposure to 4 antibiotics,the average removal rates of TN,TP,NH_(4)^(+)-N,and NO_(3)^(-)-N in the system decreased by 11.69%,17.53%,10.04%,and 4.07%,respectively.In summer,the average removal rates of TP and NH_(4)^(+)-N in the system decreased by 19.41% and 5.53%,respectively,while the average removal rates of TN and NO_(3)^(-)-N increased by 11.67% and 10.42%,respectively.This is expected to provide a reference for further improving the design parameters of constructed wetland system and increasing the removal efficiency of pollutants.