On the performance of capillary barriers as landfill cover

Kämpf, Markus; Montenegro, Héctor

doi:10.5194/hess-1-925-1997

Cited by 24 publications

(14 citation statements)

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“…They can be used as evapotranspirative covers for flat or nearly flat landfill covers (Nyhan et al, 1997;Khire et al, 2000), as lateral drains (Ross, 1990;Kampf and Montenegro, 1997) that limit percolation into the landfill, and as oxygen barriers to limit the production of acid mine drainage (Nicholson et al, 1989;Cabral et al, 1999b;Bussiere et al, 2003). The efficiency of such covers has been evaluated in the laboratory (Baker and Hillel, 1990;Stormont and Anderson, 1999;Tidwell et al, 2003;Tami et al, 2004), in the field (Aubertin, 1997;Barth and Wohnlich, 1999;von Der Hude et al, 1999) and by means of numerical simulations (Akindunni et al, 1991;Oldenburg and Pruess, 1993;Webb, 1997;Morris and Stormont, 1999 In porous materials, water percolates downward due to gravitational forces and is retained by capillary forces.…”

Section: Short Review Of Previous Studiesmentioning

confidence: 99%

Design of Inclined Covers with Capillary Barrier Effect

Parent

Cabral

2006

Geotech Geol Eng

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A design procedure is proposed to minimize water infiltration into landfills by optimizing the water diversion length of inclined covers with capillary barrier effect (CCBE). This design procedure is based on a conceptual, mathematical and numerical approach and aims at selecting materials and optimizing layer thickness. Selection among candidate materials is made based on their hydraulic conductivity functions and on a threshold infiltration rate imposed on the designer. The capillary break layer (CBL; bottom layer) is characterized by a weak capillarity, while the moisture retention layer (MRL; upper layer) is characterized by a compromise between strong capillarity and high hydraulic conductivity. The thickness of the CBL corresponds to the height where suction reaches its maximum value for a given infiltration rate. This height can be calculated using the Kisch [Ge´otechnique 9 (1959)] model. The optimal thickness of the MRL is determined by applying an adaptation of the Ross [Water Resources Research 26 (1990)] model. The results obtained using the proposed design procedure were compared to those obtained from numerical simulations performed using a finite element unsaturated seepage software. The procedure was applied for two cover systems; one where deinking by-products (DBP) were used as MRL and sand as CBL and another where sand was used as MRL and gravel as CBL. Using this procedure, it has been shown that an infiltration control system composed of thin layers of sand over gravel is highly efficient in terms of diversion length and that its efficiency can be enhanced by placing a hydraulic barrier -such as a layer of DBP -above the MRL.

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Section: Short Review Of Previous Studiesmentioning

confidence: 99%

Design of Inclined Covers with Capillary Barrier Effect

Parent

Cabral

2006

Geotech Geol Eng

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“…CCBEs have been used as an alternative to classical final cover designs for landfills and mine reclamation projects (Morel-Seytoux 1995;Stormont 1996;Kämpf and Montenegro 1997;von Der Hude and Huppert 1998;Barth and Wohnlich 1999;Kämpf et al 1999;Morris and Stormont 1999;von Der Hude et al 1999;Khire et al 2000;Aubertin and Bussiere 2001;Bussière et al 2003;Kämpf et al 2003;Wawra and Holfelder 2003;Berger et al 2005;Aubertin et al 2006). In the case of mine site reclamation projects, CCBEs are often used as oxygen barriers in order to limit acid mine production Bussière et al 2001Bussière et al , 2003Molson et al 2008).…”

Section: Basic Principles Of Capillary Barriers (Cb)mentioning

confidence: 99%

“…The effectiveness of CCBEs has been assessed in the laboratory (Bussière et al , 1998Kämpf and Montenegro 1997;Stormont and Anderson 1999;Kämpf et al 2003;Tidwell et al 2003;Yang et al 2004), in the field (Stormont 1995a;Stormont et al 1996;Aubertin et al 1997;Barth and Wohnlich 1999;von Der Hude et al 1999;Cabral et al 2007), as well as by numerical simulations (Akindunni et al 1991;Oldenburg and Pruess 1993;Bussière et al 1995Bussière et al , 2003Kämpf and Montenegro 1997;Webb 1997;Morris and Stormont 1999;Khire et al 2000;Zhan et al 2001Zhan et al , 2006Aubertin et al 2006Aubertin et al , 2009Cifuentes et al 2006).…”

Section: Basic Principles Of Capillary Barriers (Cb)mentioning

confidence: 99%

Assessment of the Design of an Experimental Cover with Capillary Barrier Effect Using 4 Years of Field Data

2011

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One important step in the design of inclined covers with capillary barrier effect (CCBE) is the determination of the water diversion length (DL). Numerical simulations can predict the DL more precisely than steady-state analytical solutions. Nevertheless, as simplified methods have always been part of engineering design, the application of analytical solutions with conservative boundary conditions, may allow engineers to make reasonable predictions, particularly during the pre-feasibility stage of a project. In this study, a CCBE was designed, constructed and instrumented at the Saint-Tite-desCaps landfill, Quebec, Canada. This CCBE included a seepage control layer superimposing a sand-gravel capillary barrier. The seepage control layer was made up of deinking by-products (DBP), an industrial byproduct that was previously disposed of as waste. The capillary barrier was designed using an adaptation of the Ross analytical solution and the scenario considered was that of steady-state flow during constant seepage flow applied uniformly at the top of the sandgravel capillary barrier. Although these conditions appear simplistic, they were deemed reasonable because placement of the seepage control layer on the top of the capillary barrier led to very low suctions at the interface, thereby allowing uniform downward seepage rates, limited by the saturated hydraulic conductivity of the DBP. In this paper, a discussion about the behaviour of the cover system based on 4 years of field data from several instruments is presented. The challenge of using DBP, more precisely the settlement of the DBP layer and its impact on k sat , is also assessed. The DL was reassessed considering the new k sat . A discussion on the validity of employing analytical solutions to determine DL is also presented. This paper illustrates how certain variables affect the design of inclined CCBEs that include a highly compressible material as seepage control layer.Keywords Cover with capillary barrier effect (CCBE) Á Diversion length Á Seepage control layer 1 Introduction

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“…Because of the advantages associated with limiting percolation and low cost, CBCs are suggested as types of alternative earthen final cover. Since the 1990s, many D r a f t researchers have performed theoretical and experimental studies on the hydrological performance of CBCs (Kämpf et al 1997;Khire et al 1999;Scanlon et al 2005;Aubertin et al 2006Aubertin et al , 2009Abdolahzadeh et al 2011). Numerical simulations were also carried out to investigate the water balance of CBCs (Morris et al 1997;Khire et al1997;Ogorzalek et al 2008;Zhang et al 2009;Zhan et al 2012).…”

Section: R a F T Introductionmentioning

confidence: 99%

Field measurements of water storage capacity in a loess–gravel capillary barrier cover using rainfall simulation tests

Zhan

Jiao

et al. 2017

Can. Geotech. J.

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A 30 m long × 20 m wide capillary barrier cover (CBC) test site was constructed at the Jiangcungou landfill in Xi’an, China. The cover consisted of a compacted loess layer with a thickness of 0.9 m underlain by a gravel layer. After the cover surface was kept bare and exposed to natural climate conditions for nearly 5 months, one artificial rainfall event was implemented at the site. Vegetation was established at the test site after the first rainfall event. Four months later, a second artificial rainfall event was applied to the surface of the vegetated site. The pore-water pressures (PWPs) and volumetric water contents (VWCs) of the cover were monitored using jet-filled tensiometers and time-domain reflectometry moisture probes, respectively. Surface runoff and percolation were measured using field collection devices. The field measurements demonstrated a more rapid response of PWPs to the rainfall compared to the response of the VWCs. Percolation was observed when the PWPs near the interface reached the water-entry value of the gravel at local points. At that moment, the measured VWC near the interface was less than the VWC according to the water-entry value. The observation indicated that preferential flows took place in the compacted loess during the rainfall. As a result, the maximum water storage capacity was not reached at the onset of percolation. When percolation ceased, the average PWP near the interface decreased below the water-entry value, while the VWC near the interface was higher than that at the onset of percolation. Water storage at the completion of percolation was approximately 5% greater than that at the onset of percolation. Compared with the monolithic loess cover, the loess–gravel CBC increased the available water storage capacity by 41% at the completion of percolation. Vegetation had an insignificant influence on water storage capacity.

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On the performance of capillary barriers as landfill cover

Cited by 24 publications

References 0 publications

Design of Inclined Covers with Capillary Barrier Effect

Design of Inclined Covers with Capillary Barrier Effect

Assessment of the Design of an Experimental Cover with Capillary Barrier Effect Using 4 Years of Field Data

Field measurements of water storage capacity in a loess–gravel capillary barrier cover using rainfall simulation tests

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