间歇性饮用水供应影响全球超过3亿人的健康。在莫桑比克,它主要在城市和小城镇实行。这导致供应的饮用水的频繁微生物污染,对消费者构成健康风险。在莫安巴,莫桑比克南部的一个小镇,有2500个水连接,运营战略变化的影响,即增加氯气用量,增加供应持续时间和首次冲洗,对微生物水质进行了研究,以确定最佳做法。为了这个目标,水质监测得到加强,以提供有关不同策略下452个样品的微生物污染的足够数据。在所有策略期间,水处理厂出口处的水不含符合国家标准的大肠杆菌。然而,大肠杆菌可以在家庭水平检测到。通过增加氯的用量,在分配网络的两个采样位置,显示大肠杆菌缺失的样本数量增加:在Cimento从72%增加到83%,在Matadouro从52%增加到86%.修改供水周期的数量和持续时间对分配网络中两个位置的水质都有不同的影响。在Cimento中显示出积极的效果,其中大肠杆菌和总大肠杆菌的平均浓度分别从0.54降至0.23CFU/100mL和16.7降至7.3CFU/100mL。细菌阳性样本的百分比是,然而,类似。相比之下,在Matadouro中显示出负面影响,其中阳性样品的百分比增加,平均细菌浓度略有增加:大肠杆菌从0.9至1.5CFU/100mL,总大肠杆菌17.6至23.0CFU/100mL.加强水质监测改善了维护微生物水质的操作策略。家庭饮用水的大肠杆菌污染可能表明分配中的再污染或家庭一级不安全的卫生习惯。家庭水平的粪便污染的存在表明病原体的潜在存在对消费者构成健康风险。增加氯用量可确保良好的微生物饮用水质量,但改变供应周期数没有这种影响。
Intermittent drinking water supply affects the health of over 300 million people globally. In Mozambique, it is largely practiced in cities and small towns. This results in frequent microbial contamination of the supplied drinking water posing a health risk to consumers. In Moamba, a small town in Southern Mozambique with 2,500 water connections, the impact of changes in operational strategies, namely increased chlorine dosage, increased supply duration and first-flush, on the microbial water quality was studied to determine best practices. To that aim, water quality monitoring was enhanced to provide sufficient data on the microbial contamination from 452 samples under the different strategies. The water at the outlet of the water treatment plant during all strategies was free of E. coli complying to the national standards. However, E. coli could be detected at household level. By increasing the chlorine dosage, the number of samples that showed E. coli absence increased at the two sampling locations in the distribution network: in Cimento from 72% to 83% and in Matadouro from 52% to 86%. Modifying the number and duration of supply cycles showed a different impact on the water quality at both locations in the distribution network. A positive effect was shown in Cimento, where the mean concentrations decreased slightly from 0.54 to 0.23 CFU/100 mL and 16.7 to 7.3 CFU/100 mL for E. coli and total coliforms respectively. The percentage of samples positive for bacteria was, however, similar. In contrast, a negative effect was shown in Matadouro where the percentage of positive samples increased and the mean bacterial concentrations increased slightly: E. coli from 0.9 to 1.5 CFU/100 mL and total coliforms 17.6 to 23.0 CFU/100 mL. Enhanced water quality monitoring improved operational strategies safeguarding the microbial water quality. The E. coli contamination of the drinking water at household level could point at recontamination in the distribution or unsafe hygienic practices at household level. Presence of faecal contamination at household level indicates potential presence of pathogens posing a health risk to consumers. Increasing chlorine dosage ensured good microbiological drinking water quality but changing the number of supply cycles had no such effect.