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首页> 外文学位 >Removal of MS2 bacteriophage, Cryptosporidium, Giardia and turbidity by pilot-scale multistage slow sand filtration.
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Removal of MS2 bacteriophage, Cryptosporidium, Giardia and turbidity by pilot-scale multistage slow sand filtration.

机译：通过中试规模的多级慢速砂滤去除MS2噬菌体，隐孢子虫，贾第鞭毛虫和浊度。

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摘要

This research aimed to address the knowledge gaps in the literature regarding the removal of waterborne pathogens (viruses and protozoa) by modified multistage slow sand filtration. In the current study, two pilot-scale multistage slow sand filtration systems were operated continuously for over two years. The pilot systems treated agricultural- and urban-impacted raw river water of variable quality with turbidity peaks over 300 NTU and seasonal cold temperatures 2°C.; The first system (Pilot 1) consisted of two independent trains that included pre-ozonation, shallow-bed upflow gravel roughing filtration, and shallow-bed slow sand filtration. Pilot 1 was a pilot-scale version of an innovative, commercially available full-scale system. The second system (Pilot 2) included a full-depth upflow gravel roughing filter, a full-depth slow sand filter, and a second shallow-depth slow sand filter in series. The SSFs of both pilots were operated at high hydraulic loading rates (typically 0.4 m/h) at the upper limit of the literature recommended range (0.05 to 0.4 m/h).; Both pilot systems provided excellent turbidity removal despite the high filtration rates. Effluent turbidity of all multistage SSF pilot systems were within the regulated effluent limits in Ontario for full-scale SSFs (below 1 NTU at least 95% of the time and never exceeded 3 NTU), despite raw water turbidity peaks over 100 NTU. The roughing filters contributed to approximately 60-80% of the full-train turbidity removal, compared to and 20-40% for the slow sand filters. On average, the second slow sand filter in pilot 2 provided almost no additional turbidity removal. The slow sand filter run lengths were short because of frequent high raw water turbidity, with about 50-80% of the runs in the range of 1-3 weeks. To prevent excessive SSF clogging and maintenance, filtration rates should be decreased during periods of high turbidity.; Seven Cryptosporidium and Giardia challenge tests were conducted on the slow sand filters of both pilot systems at varying filtration rates (0.4 or 0.8 m/h), temperatures (2 to 25°C), and biological maturities (4 to 20 months). Removal of oocysts and cysts were good regardless of sand depth, hydraulic loading rate, and water temperature in the ranges tested. Average removals in the SSFs ranged from 2.6 to >4.4 logs for Cryptosporidium oocysts and ranged from >3.8 to >4.5 logs for Giardia cysts. This was consistent with findings in the literature, where oocyst and cyst removals of >4 logs have been reported. Cryptosporidium oocyst removals improved with increased biological maturity of the slow sand filters. At a water temperature of 2°C, average removal of oocysts and cysts were 3.9 and >4.5 logs, respectively, in a biologically mature SSF. Doubling the filtration rate from 0.4 to 0.8 m/h led to a marginal decrease in oocyst removals. Sand depths in the range tested (37-100 cm) had no major impact on oocyst and cyst removals, likely because they are removed primarily in the upper section of slow sand filter beds by straining. In general, good oocyst and cyst removals can be achieved using shallower slow sand filter bed depths and higher filtration rates than recommended in the literature.; There are very few studies in the literature that quantify virus removal by slow sand filtration, especially at high filtration rates and shallow bed depths. There are no studies that report virus removal by slow sand filtration below 10°C. As such, 16 MS2 bacteriophage challenge tests were conducted at varying water temperatures (2 to >20°C) and filtration rates (0.1 vs. 0.4 m/h) between February and June 2006 on biologically mature slow sand filters with varying bed depths (40 vs. 90 cm). Biologically mature roughing filters were also seeded with MS2.; Average MS2 removals ranged from 0.2 to 2.2 logs in the SSFs and 0.1 to 0.2 logs in the RFs under all conditions tested. Virus removal by slow sand filtration was strongly dep
机译：这项研究旨在解决文献中有关通过改进的多级慢速砂滤去除水生病原体（病毒和原生动物）的知识差距。在当前的研究中，两个中试规模的多级慢砂过滤系统连续运行了两年以上。试点系统处理了农业和城市受影响的河水质量不一，浊度峰值超过300 NTU，季节性寒冷温度<2°C；第一个系统（试点1）由两个独立的流程组成，包括预臭氧化，浅层上流砾石粗滤和浅层慢沙过滤。试点1是创新的，商用全尺寸系统的试验规模版本。第二个系统（试点2）包括一个全深度上流砾石粗滤器，一个全深度慢沙滤器和一个串联的第二个浅深度慢沙滤器。两名飞行员的SSF在较高的液压负载率下（通常为0.4 m / h）以文献推荐范围的上限（0.05至0.4 m / h）运行。尽管具有高过滤率，这两种中试系统仍可提供出色的浊度去除效果。尽管原水浊度峰值超过100 NTU，但所有多级SSF中试系统的污水浊度均在安大略省的全尺寸SSF的规定污水限值内（至少95％的时间低于1 NTU，并且从未超过3 NTU）。与慢速砂滤器相比，粗滤器约占全系列浊度去除率的60-80％，而慢砂滤器约占20-40％。平均而言，飞行员2中的第二个慢砂滤池几乎没有提供额外的浊度去除功能。由于频繁的高生水浊度，砂滤器的运行时间很短，约有50-80％的运行时间为1-3周。为防止SSF过多堵塞和维护，在高浊度期间应降低过滤速率。在两个中试系统的慢砂滤池上，以不同的过滤速率（0.4或0.8 m / h），温度（2至25°C）和生物成熟度（4至20个月）进行了7次隐孢子虫和贾第鞭毛虫挑战试验。在测试范围内，无论沙子深度，水力加载速率和水温如何，卵囊和囊肿的去除效果都很好。对于隐孢子虫卵囊，SSF中的平均去除量为2.6至> 4.4 log，对于贾第虫囊肿，平均去除量为> 3.8至> 4.5 log。这与文献中发现的卵囊和囊肿去除率> 4 log的发现是一致的。随着慢砂滤池生物成熟度的提高，隐孢子虫卵囊的去除率也提高了。在2°C的水温下，在生物学上成熟的SSF中，卵囊和囊肿的平均去除率分别为3.9和> 4.5 log。过滤速度从0.4倍增至0.8 m / h导致卵囊去除率略有下降。在测试范围内（37-100厘米）的砂深度对卵囊和囊肿的去除没有重大影响，可能是因为它们主要是通过过滤在慢速砂滤床的上部去除的。通常，使用比文献中推荐的浅的慢砂滤床深度和更高的过滤速率，可以很好地清除卵囊和囊肿。文献中很少有研究通过缓慢的砂滤来定量去除病毒，特别是在高过滤速率和浅层深度时。没有研究报告在10°C以下通过缓慢的砂滤去除病毒。因此，在2006年2月至2006年6月之间，在生物学成熟的，具有不同床深的慢砂滤池上，在变化的水温（<2至> 20°C）和过滤速率（0.1 vs. 0.4 m / h）下进行了16次MS2噬菌体挑战试验（40对90厘米）。生物成熟的粗滤器也接种了MS2。在所有测试条件下，SSF中的平均MS2清除范围为0.2至2.2个对数，而RF中的平均MS2清除范围为0.1至0.2个对数。通过缓慢的砂滤去除病毒的能力很强

著录项

  • 作者

    DeLoyde, Jeffrey L.;

  • 作者单位

    University of Waterloo (Canada).;

  • 授予单位 University of Waterloo (Canada).;
  • 学科 Engineering Civil.
  • 学位 M.A.Sc.
  • 年度 2007
  • 页码 269 p.
  • 总页数 269
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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