臭氧联合粉末活性炭与超滤对二级出水中抗性基因的去除效能

抗生素抗性基因(Antibiotic Resistance Genes,ARGs)作为新兴环境污染物,已对人类健康造成威胁。最近的研究表明,污水处理厂的废水是环境中ARGs的重要来源。采用臭氧结合粉末活性炭(Powdered Activated Carbon,PAC)与超滤(Ultrafiltration,UF)组合对污水处理厂二级出水进行深度处理,研究了组合工艺对二级出水中ARGs及溶解性有机物(Dissolved Organic Carbon,DOC)的去除效能,并分析了ARGs与DOC、16S rD NA及1类整合子(intⅠ1)的相关性。结果表明:臭氧质量浓度为2 mg/L时,组合工艺对抗性基因tet A、tet G、tet X、suⅠl、suⅡl及intⅠ1和16S rD NA的去除效果最好,对DOC去除率为63. 5%;经拟合分析得知,ARGs的削减与DOC、inⅠt1及16S rD NA的去除均呈显著正相关性。综上所述,臭氧联合粉末活性炭与超滤组合可以有效去除二级出水中的抗生素抗性基因。

Removal efficiency of the antibiotic resistance genes in the secondary effluent via the ozone combined powdered activated carbon and ultrafiltration

The present paper is engaged in a study of antibiotic resistance genes(short for ARGs),for the emerging environmental contaminants have become a serious threat to the human health.As is well known,recent studies indicate that the effluent from the sewage treatment plants has become a significant point source of ARGs released into the environment.Here,in this paper,we would like to present our investigation results of ozone combined with the powdered activated carbon(PAC)and ultrafiltration(UF)for the advanced treatment of the secondary effluent from the sewage treatment plant,so as to investigate and determine the optimal dosage of ozone for the removal of ARGs and the dissolved organic carbon(DOC)in the secondary effluent and the correlation between the ARGs and the DOC,as well as between the 16 S rD NA and the class I integron intⅠ1.When the dosage of ozone is 2 mg/L,the detection concentrations of the5 ARGs and intⅠ1 genes can be made lowest in the water samples,whereas the concentrations of tet A,tet C,tet G,sulI,sulI I and inⅠt1 can be made equal to 102.71 copies/mL and 104.56 copies/mL,103.40 copies/mL,104.21 copies/mL,104.02 copies/mL,106.14 copies/mL,respectively.With the increase of the concentration of ozone,the abundance of ARGs can be made fluctuated.The above gained results indicate that,the optimal dosage of ozone is 2 mg/L.The O3-PAC-UF combined process can help to produce the best removal effect on the tet A,tet G,tet X,sulI,sulI I and inⅠt1,as well as 16 S rD NA at the optimal ozone dosage.And,in the process,the specific removal amounts can be made to achieve 3.17-lg,2.47-lg,2.98-lg,2.83-lg,3.04-lg,2.56-lg,3.29-lg,correspondingly.Therefore,the effect of reduction proves remarkable.In addition,the O3-PAC-UF is potential in raising the DOC removal rate up to 63.5%,hence,raising the removal effect higher than that of PAC-UF.Besides,ozone can also help to change the structure and properties of the organic substances and promote the adsorptive rate of PAC,so as to reduce the DOC content in secondary effluent marvelously.In addition,significant removal correlations can be observed and determined between ARGs and inⅠt1,DOC,16 S rD NA.Therefore,the removal of DOC,class I integrant inⅠt1 and bacteria in secondary effluent can all contribute themselves to the ARGs reduction.The above results indicate that O3-PAC-UF combined process can play a promising role in ARGs reduction in the secondary effluents from the sewage treating plants.