| With the wide application of nanomaterials,a large number of production and daily articles containing nanomaterials will be released into the environment through a variety of ways.For example,with the discharge of domestic sewage and industrial wastewater into the sewage treatment plant,it will have a certain impact on the sewage treatment system.In addition,in recent years,a large number of Antibiotic use,make the environment to induce a large number of Antibiotic Resistance Genes（ARGs）,this phenomenon on human health and ecological environment has a serious potential threat.However,although a large number of studies have been carried out on environmental pollution caused by nanomaterials and antibiotics,and great achievements have been made,there are few relevant reports on the influence and mechanism of combined pollution caused by nanomaterials and antibiotics on the operation of sewage treatment system and ARGs transfer.Therefore,this article selected nanometer copper oxide（Cu O NPs）and sulfamethoxazole for the typical representative of nanometer metal oxide and antibiotics,using activated sludge process（SBR）,sequence batch explores such nanomaterials and antibiotic compound pollution of SBR sewage treatment system of operation and the ARGs transfer effects and mechanisms of action,for the environmental effects of new pollutants and spread of resistance genes control provides theory basis.In this paper,the effects of single contamination with different concentrations of Cu O NPS on the operation of SBR system and the succession law of microbial community structure in the system were studied.The experimental results show that the removal efficiency of COD,ammonia nitrogen and total nitrogen in the SBR system is more than 97%in the period（8 h）after short-term exposure（8 h）and long-term exposure（8 h）.After long-term exposure（50 d）,the removal efficiency of COD in the system is more than 90%,and the removal efficiency of ammonia nitrogen and total nitrogen reaches 98%.Therefore,short-term exposure and long-term exposure did not have significant effects on the degradation of organic matter in the system,the removal of ammonia nitrogen and total nitrogen.At the same time,the single contamination of Cu O NPS promoted the growth of Nitrospira and the Sensu＿Stricto＿1,Bdellovibrio,Caenimonas and Dechloromonas in the system.By adding 0.5 mg/L sulfamethoxazole and Cu O NPS（0.1,1,10 mg/L）to the system,the effects of sulfamethoxazole and Cu O NPS combined pollution on the operating efficiency of the SBR system and the changes of microbial community structure in the system were investigated.The results showed that the compound pollution under long exposure（50 d）and cycle,after long-term exposure of SBR system out of the water of the degradation of organic matter,ammonia nitrogen and total nitrogen removal with the control group had no significant difference,after long-term exposure of COD,ammonia nitrogen and total nitrogen removal efficiency was 60%,99%and 50%,respectively,after long-term exposure period the COD removal efficiency is 70%.Although the removal of phosphorus in the long-term exposure process was affected in a certain period of time,resulting in the reduction of the removal efficiency,with the continuous operation of the system,the efficient removal efficiency of phosphorus was restored,and the removal efficiency reached75%.However,in the period after long-term exposure,the accumulation of nitrate nitrogen in MSb R1 and MSb R3 in the experimental group was promoted,and the removal of total nitrogen in the period was inhibited.The removal efficiency of sulfamethoxazole in both the experimental group and the control group was as high as 99%,and the removal route was not affected by the compound pollution.Compound pollution will inhibit the growth of phosphorous accumulating bacteria Candidatus＿Accumulibacter,Microlunatus and Dechloromonas,and promote the growth of glycan bacteria Candidatus＿Rhabdochlamydia.In this study,the abundance changes of resistance genes in SBR system were investigated by high-throughput Q-PCR and other molecular biological techniques,and the mechanism of transmission and diffusion of resistance genes in the system under compound contamination was analyzed.The theoretical analysis and experimental results showed that the single Cu O NPs pollution could promote the accumulation of gene intⅠ1 and the total amount of target ARGs in the effluent,and 0.1 mg/L Cu O NPs had the most significant promoting effect on the accumulation of target ARGs in the effluent,which was 2.80 times that of the control group.Meanwhile,bla TEM gene,erm B gene,sulⅠgene,tet Q gene and bla OXA-10 gene were easily accumulated in efflorescence.0.1 and 1 mg/L Cu O NPS promoted the transmission of target ARGs and intⅠ1 in the sludge,but 10 mg/L Cu O NPS inhibited its transmission in the sludge.Sulfamethoxazole and Cu O NPS combined pollution can promote the accumulation and transmission of target ARGs and gene intⅠ1 in effluents and sludge,and 0.5 mg/L sulfamethoxazole+10 mg/L Cu O NPS has the most significant promoting effect on the accumulation of target ARGs in effluents,which is 3.87times of that in the control group.In particular,combined pollution can promote the horizontal transfer of sulfonamides resistance gene sulⅠgene and sulⅡgene in discharge water.In addition,tet O gene and bla OXA-10 gene are easy to accumulate in effluent under combined pollution.The results showed that the transmission mode of ARGs was mainly dependent on vertical transfer,whether Cu O NPs were single contamination or combined contamination with antibiotics. |
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