Characterization of sludges. Filtration properties

This paper presents the results of an experimental study aimed at evaluating the elementary filtration properties of a fine cement grout injected in a sand. In a first step, the experimental setup or filtration cell, specially developed for injecting thin samples of sand put under stress, is presented. Next, the results of an experimental programme carried out with this cell are presented, allowing for the study of the influence of basic parameters (density index, consolidation stress, cement concentration in the grout, and injection flow rate) on the filtration properties of a typical grout composed of fine cement. A filtration coefficient is then defined, allowing for characterization of the elementary filtration properties of the tested grout by the sand matrix. Finally, the respective influence of tested parameters on the value of this coefficient is presented and discussed.Key words: cement grout, suspension, filtration, flow, sand, injection.

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Influence of Calcite in the Filtration Properties of Clay Dispersions

Materials Science Forum ◽

10.4028/www.scientific.net/msf.881.212 ◽

2016 ◽

Vol 881 ◽

pp. 212-217

Author(s):

Karine Castro Nóbrega ◽

Luciana Viana Amorim

Keyword(s):

Bentonite Clay ◽

Average Diameter ◽

Clay Sample ◽

X Ray Diffraction ◽

X Ray ◽

Low Viscosity ◽

Fixed Concentration ◽

Two Samples ◽

Filtration Properties

This project had as objective to evaluate the influence of the content and particle size of the calcite in the filtration properties of clay dispersions. For that, it was realized the characterization of a bentonite clay sample using X-Ray Fluorescence and X-Ray Diffraction. In addition, two samples of calcite (CaCO3) were granulometrically analyzed by Laser Diffraction. The dispersions were prepared with fixed concentration of clay (10g) and different concentrations of carboxymethylcellulose of low viscosity (0 to 2g), and calcite (0 to 20g). After 24 hours of repose, it were determined the filtration properties (filtrate volume (FV), mudcake thickness (h), and mudcake permeability (k)). It was observed that the lowest filtrate volume was acquired using CaCO3 sample with the lowest average diameter, and, also, a bigger concentration of calcite was not able to promote a considerable reduction of the filtrate.

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Hydraulic characterization of laterals as applied to selected radial collector wells at Belgrade groundwater source

Geoloski anali Balkanskog poluostrva ◽

10.2298/gabp1677033p ◽

2016 ◽

pp. 33-42 ◽

Cited By ~ 1

Author(s):

Dusan Polomcic ◽

Djordjije Bozovic ◽

Dragoljub Bajic

Keyword(s):

Threshold Value ◽

Functional Condition ◽

Present Condition ◽

Hydrodynamic Analysis ◽

Groundwater Availability ◽

Level Regime ◽

Skin Zone ◽

Groundwater Source ◽

Filtration Properties

The paper examines the possibility of hydraulic characterization of radial well laterals in a manner that does not require prior hydrodynamic analysis by simulating groundwater extraction conditions on a numerical model. The first step of the proposed approach is to assess the groundwater level regime formed in the capture zone when the well is operating, which is indicative of the functional condition of the laterals and the aquifer potential in terms of groundwater availability. Then the efficiency of the laterals is examined through the hydraulic function of the skin zone, depending on its filtration properties. An expression for groundwater flow from the aquifer to the laterals (commonly used to simulate laterals on a hydrodynamic model) is employed to define representative values of the conductance coefficient of the skin zone (as an indicator of colmation), and then applied to several wells at Belgrade Groundwater Source. The present research shows that a conductance coefficient of [Ks/ds]=1.0?10-4 s-1 can be considered as the threshold value in relation to which the effects of colmation of well laterals are exhibited, which is consistent with the results reported by researchers who studied the effect of skin zone conductance on the occurrence and nature of the so-called early drawdown at radial collector wells. In addition to gaining insight into the present condition of the laterals, the proposed approach can be used to study the progress of colmation at different points in time and to quantify the effectiveness of regeneration of laterals.

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