scholarly journals Influence of hydraulic conductivity on communities of microorganisms and invertebrates in porous media: a case study in drinking water slow sand filters

2006 ◽  
Vol 68 (1) ◽  
pp. 100-108
Author(s):  
Laurie Mauclaire ◽  
Andreas Schürmann ◽  
Florian Mermillod-Blondin
Keyword(s):  
Porous Media ◽  
Drinking Water ◽  
Hydraulic Conductivity ◽  
Sand Filters

scholarly journals Grain displacement during backwash of drinking water filters

2020 ◽  
Author(s):  
Loren Ramsay ◽  
Feng Du ◽  
Majbritt Lund ◽  
Haiyan He ◽  
Ditte A. Søborg
Keyword(s):  
Grain Size ◽  
Drinking Water ◽  
Pilot Scale ◽  
Sand Filters ◽  
Active Biomass ◽  
Four Dimensions ◽  
Study Country ◽  
Water Filters ◽  
Practical Implications

Abstract Backwashing rapid sand filters causes inadvertent displacement of filter media grains from their previous depths. This displacement can affect the hydraulic function of filters by mixing or segregating media grains, and the function of biofilters through displacement of active biomass and coatings from proper depths. This study quantifies grain displacement in a pilot-scale filter using tracer grains of colored sand, glass beads, anthracite and garnet to determine the effect of grain size, density and shape on grain displacement. Statistical moments are used to describe the depth distributions resulting from displacement during backwashing. Results show that significant grain displacement occurs during backwash consisting of air scour, air-and-water wash and sub-fluidization water-only wash. Here, displacement is largely independent of grain size, density and shape. When fluidization backwash is used, greater displacement and more dependence on grain characteristics is seen. A variety of grain movement phenomena can be observed during the backwashing steps, indicating that grain movement and therefore the resulting displacement is highly inhomogeneous in four dimensions. These results have direct practical implications for the design of rapid sand filters and the optimization of backwashing procedures, while suggesting that the current widespread backwashing practice used in the case study country (Denmark) should be abandoned.

Ensuring access to water in an emergency context: Towards an overexploitation and contamination of water resources?

2021 ◽  
pp. 096466392110316
Author(s):  
Chloé Nicolas-Artero
Keyword(s):  
Drinking Water ◽  
Water Resources ◽  
Qualitative Methods ◽  
Water Scarcity ◽  
Water Rights ◽  
Environmental Crisis ◽  
Supply Network ◽  
Mining Pollution ◽  
Access To Water

This article shows how geo-legal devices created to deal with environmental crisis situations make access to drinking water precarious and contribute to the overexploitation and contamination of water resources. It relies on qualitative methods (interviews, observations, archive work) to identify and analyse two geo-legal devices applied in the case study of the Elqui Valley in Chile. The first device, generated by the Declaration of Water Scarcity, allows private sanitation companies to concentrate water rights and extend their supply network, thus producing an overexploitation of water resources. In the context of mining pollution, the second device is structured around the implementation of the Rural Drinking Water Programme and the distribution of water by tankers, which has made access to drinking water more precarious for the population and does nothing to prevent pollution.

Identification of MIB producers and odor risk assessment using routine data: A case study of an estuary drinking water reservoir

2021 ◽  
Vol 192 ◽  
pp. 116848
Author(s):  
Ming Su ◽  
Yiping Zhu ◽  
Zeyu Jia ◽  
Tingting Liu ◽  
Jianwei Yu ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Water Reservoir ◽  
Routine Data ◽  
Drinking Water Reservoir

Understanding Immiscible Natural Gas Huff-N-Puff Seepage Mechanism in Porous Media: A Case Study of CH4 Huff-N-Puff by Laboratory Numerical Simulations in Chang-7 Tight Core

2021 ◽  
Vol 30 (3) ◽  
pp. 2397-2411
Author(s):  
Taiyi Zheng ◽  
Zhengming Yang ◽  
Xiangui Liu ◽  
Yutian Luo ◽  
Qianhua Xiao ◽  
...  
Keyword(s):  
Porous Media ◽  
Natural Gas ◽  
Numerical Simulations
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