Analysis of the monitoring results of microbial indicators in drinking water in rural areas of Santai County from 2018 to 2022
Objective To analyze the monitoring results of microbial indicators in drinking water in rural areas of Santai County from 2018 to 2022,to analyze the impact of treatment methods and disinfectant types on microbial indicators,and to provide reference and suggestions for drinking water safety in rural areas of the county.Methods In accordance with the Water Quality and Sanitation Monitoring Programme from 2018 to 2022,drinking water monitoring stations in rural areas were established throughout the county.The numbers of samples in each year were 252,248,252,252 and 404,respectively,with a total of 1 408 samples.The total colony count was determined by plate counting method,and total coliform and Escherichia coli were quantified by 51-well quantitative plate method based on enzyme substrate technique.Water quality assessment was conducted following GB/T 9-2006 standards.SPSS 16.0 software was employed to conduct statistical analysis.Median test,Kolmogorov-Smirnov Z test and x2 test method were used,and the test level was α=0.05.Results From 2018 to 2022,the qualified rates of microbial indicators of rural drinking water in Santai County were 64.7％,63.7％,57.9％,62.7％and 87.6％,respectively.The medians of the total number of colonies and the total coliform generally increased first and then decreased,and the median of Escherichia coli decreased year by year.There were significant differences in the median of the number of colonies among different years(x2=11.531,P=0.021).There were no significant differences in the medians of the total coliform and the Escherichia coli(x2=5.932 and 8.207,P=0.204 and 0.084).The qualified rates of microbial indicators of only sterilized and conventionally treated water samples(79.34％and 75.97％)were significantly higher than that of untreated water samples(31.42％),and the differences were statistically significant(x2=221.065,P＜0.001).The qualified rate of microbial indicators of disinfection water samples was higher than that of conventional water samples,but the difference was not statistically significant(x2=1.712,P=0.191).The total number of bacterial colonies,total coliform bacteria and Escherichia coli in the water samples with disinfection and conventional treatment were lower than those in the untreated water samples,and the differences in the total number of bacterial colonies and the Escherichia coli were statistically significant(x2=24.117 and 6.689;P＜0.001 and P=0.035).The qualified rate of microbial indicators of high purity chlorine dioxide treated water samples(76.7％)was significantly lower than that of bleach powder treated water samples(88.5％),and the difference was statistically significant(x2=9.452,P=0.002).There was no significant difference in the medians of the total number of colonies,the total coliform and the Escherichia coli in water samples treated with high purity chlorine dioxide compared with water samples treated with bleach powder(Z=-1.397,-1.086,-0.63,all P＞0.05).Conclusions The qualified rate of microbial indicators of drinking water in rural areas of Santai County was at a low level.Disinfection could improve the qualified rate of microbial indicators in rural drinking water and reduce the detection level of microbial indicators in drinking water,but the effect of conventional disinfection was not good.The disinfection effect of high purity chlorine dioxide was lower than that of bleaching powder.
NETL
NSTL
万方数据
