ABSTRACT Four household slow sand filters were made out of PVC and operated in continuous and intermittent flows, with and without using a float to control the maximum level of water inside the units. The efficiency was evaluated as a function of Escherichia coli reduction and turbidity in water from the study prepared with kaolinite and E. coli suspension. The correlation of the efficiencies with the following operational parameters was evaluated: operating time, time after maintenance, filtration rate and head loss divided by bed thickness. The filters were classified as intermittent with float (IFF), intermittent without float (IF), continuous with float (CFF) and continuous without float (CF). IFF, CFF and CF had a non-woven blanket installed on top of the media. The results indicated that no significant statistical differences were found in E. coli reduction and turbidity between IFF and IF, however the former had filter runs over 80 days and the latter almost a quarter of this value. CFF matured faster and had less turbidity remaining in relation to CF. When comparing IFF with CFF, the former presented lower turbidity remaining (0.89 ± 0.44 NTU versus 1.24 ± 0.91NTU), but a lower reduction of E. coli (1.40 ± 0.61 log versus 2.29 ± 0.74 log). The time after maintenance was the most important operational parameter when evaluating the efficiencies. The float helped to mature the filter more quickly in a continuous flow and, together with a non-woven blanket, extended the filter runs in the intermittent flow. GRAPHICAL ABSTRACT

中文翻译：

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带和不带水位控制的家用慢砂过滤器：连续和间歇流动效率

摘要 四个家用慢砂过滤器由 PVC 制成，在连续和间歇流中运行，使用或不使用浮子来控制单元内的最大水位。根据用高岭石和大肠杆菌悬浮液制备的研究，将效率评估为大肠杆菌减少和水中浊度的函数。评估了效率与以下操作参数的相关性：操作时间、维护后时间、过滤速率和水头损失除以床层厚度。过滤器分为间歇带浮子（IFF）、间歇不带浮子（IF）、连续带浮子（CFF）和连续不带浮子（CF）。IFF、CFF 和 CF 在介质顶部安装了无纺布毯。结果表明，在 E 中没有发现显着的统计差异。IFF 和 IF 之间的大肠杆菌减少和浊度，但是前者的过滤器运行时间超过 80 天，而后者几乎是该值的四分之一。CFF 成熟得更快，与 CF 相比，剩余的浊度更少。将 IFF 与 CFF 进行比较时，前者的剩余浊度较低（0.89 ± 0.44 NTU 与 1.24 ± 0.91NTU），但大肠杆菌的减少较低（1.40 ± 0.61 log 与 2.29 ± 0.74 log）。在评估效率时，维护后的时间是最重要的操作参数。浮子有助于在连续流中更快地成熟过滤器，并与无纺布毯一起延长过滤器在间歇流中的运行时间。图形概要 CFF 成熟得更快，与 CF 相比，剩余的浊度更少。将 IFF 与 CFF 进行比较时，前者的剩余浊度较低（0.89 ± 0.44 NTU 与 1.24 ± 0.91NTU），但大肠杆菌的减少较低（1.40 ± 0.61 log 与 2.29 ± 0.74 log）。在评估效率时，维护后的时间是最重要的操作参数。浮子有助于在连续流中更快地成熟过滤器，并与无纺布毯一起延长过滤器在间歇流中的运行时间。图形概要 CFF 成熟得更快，与 CF 相比，剩余的浊度更少。将 IFF 与 CFF 进行比较时，前者的剩余浊度较低（0.89 ± 0.44 NTU 与 1.24 ± 0.91NTU），但大肠杆菌的减少较低（1.40 ± 0.61 log 与 2.29 ± 0.74 log）。在评估效率时，维护后的时间是最重要的操作参数。浮子有助于在连续流中更快地成熟过滤器，并与无纺布毯一起延长过滤器在间歇流中的运行时间。图形概要 在评估效率时，维护后的时间是最重要的操作参数。浮子有助于在连续流中更快地成熟过滤器，并与无纺布毯一起延长过滤器在间歇流中的运行时间。图形概要 在评估效率时，维护后的时间是最重要的操作参数。浮子有助于在连续流中更快地成熟过滤器，并与无纺布毯一起延长过滤器在间歇流中的运行时间。图形概要