| The excessive use and incomplete metabolism of antibiotics make it widespread in the environment.In addition to its own chemical pollution to the environment,there are potential hazards,the development of microorganisms resistance in the environment.This will lead to the massive propagation of Antibiotic Resistant Bacteria?ARB?in the environment.And the Antibiotic resistance genes?ARGs?in the environment will move vertically and horizontally or even selectively in the organism and the environment.The ecological environment is undoubtedly a huge repository of antibiotic resistant bacteria and resistant genes.The water environment is more easily polluted due to its strong mobility and poor controllability.The drinking water environment directly related to human health should be taken seriously.Domestic understanding of resistance bacteria and resistance genes in drinking water sources in different regions is not comprehensive enough,and the removal effect of antagonistic bacteria and resistant genes in drinking water treatment process is almost unknown.Therefore,this subject examines the abundance of ARB and ARG in the urban drinking water system,and probes into the effective technology for controlling the pollution of ARB and ARG.It is expected to provide reliable data support for the evaluation of rivers and lakes,and technical support for the actual operation of watertreatment.This study will detect the bacterias?total bacteria,AMX ARB,and SMZ ARB?and genes?Sul?,Sul?,blaCTM-X,int I1,and 16S rDNA?in Yellow River of Jinan section,water reservoirs,and drinking water treatment plant,analye the ARB and ARG removal of different treatment process,and discuss the effective process of controlling resistance pollution.The main coclusions are as follows.The results show that the total bacterias,AMX ARB,and SMZ ARB in the Yellow river basin and water reservoirs in three seasons were between 102—104CFU/mL.The major genus in above were Bacillus and Pseudomonas.And the Bacillus decreased with the decreasing of temperature.The absolute concentration of Sul?,Sul?,blaCTM-X,and int I1 were between103—105copies/mL,and for 16S rDNA between 105—108copies/mL.Beta-lactam resistance gene(blaCTM-X)was higher than the sulfonamides?Sul?and Sul??in total genes.According to the correlation analysis,the sulfonamides?Sul I and Sul II?and beta lactam resistance genes?blaCTX-M?were significantly correlated with int I1?p<0.01?.The most significant process for removing ARB and ARG in the urban water treatment system is sand basin and drinking water treatment plant.The removal rate of bacteria?total bacteria,AMX ARB,and SMZ ARB?was up to 86.62%.And the removal rate of genes(Sul?,Sul?,blaCTM-X,int I1,and 16S rDNA)was as high as 0.66 log.The above three kinds of bacteria were not detected in outflow of drinking water treatment plants.And the removal rates of genes were up to 2.49 log.Compared with the sand basin and drinking water treatment plant,in reservoir the removal rate of bacteria was not more than 20%.And for the genes,the removal rate was less than 0.15 log.For the drinking water treatment,the total bacteria,AMX ARB,and SMZ ARB in coagulation and sedimentation process are basically lower than 45%.And for Sul?,Sul?,blaCTM-X,int I1,and 16S rDNA,the removal rates were between 0.03-0.25log.There are positive removal rate and negative removal rate in the filtration process.In other words,the filtered water has possibility of increasing bacteria and genes.And its biosafety needs to be emphasized.Compared with other processes,the disinfection process has a significant effect on the removal of this kind of pollutants.After treated with chlorine disinfection process,the total bacteria,ARB of AMX and SMZ in water were basically not detected by pure culture method.The removal rate of three kinds of bacteria by ozone process was between 36.87%-56.35%,16.99%-71.7%and 6%-46.58%.The highest gene removal rate of chlorination disinfection process can reach 1.97log.And the removal rate of these five genes by ozone disinfection treatment process is 0.25log-0.71og.Based on the above experimental research,we discussed the effects of ceramic membrane technology,UV,O3,UV/H2O2,and UV/O3 process.The results are UV/H2O2>ceramic membrane technology?100nm?>UV/O3>UV>O3.UV/O3 process has no remarkable higher than the UV process.And that process should add UV and O3,which causes the high cost.Therefore,we only analyze the economic cost of UV process,UV/H2O2process,and ceramic membrane technology?100nm?.When the design capacity is 200thousand m3/d,the equipment cost of those three technology is 750 thousand,840 thousand,and 732 thousand yuan,respectively,which is no more than 100 thousand yuan.And the daily operation cost of the UV/H2O2 process is much higher than the other two.Although the removal efficiency and economic cost make the UV process to be the first choice among the three processes mentioned above,but the actual UV process cannot achieve the high dosage in the laboratory.The operation cost of the ceramic membrane?100nm?is slightly higher.But the most important is that it can replace the traditional filtration process,and has effective treatment effect on ARB and ARG. |
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