The effectiveness of “clay” liners as basal isolation of landfills: a case study (original) (raw)
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Clay geosynthetic barriers performance in landfill covers
Clay geosynthetic barriers (GBR-Cs) used in landfill covers must ensure lining on the long term. The primary mode of ageing of bentonite GBR-Cs in covers is the coupling of cation exchange and hydrationdesiccation cycles. The objective of this paper is to synthesize the optimal conditions to prevent a loss of performance of GBR-Cs in covers with time, based on a literature review. Various parameters will be discussed. The literature review will put in light the lack of consistent information from study to study. This enforces the need for a list of information to collect in future excavations. Such a list is proposed in the third section of this paper followed by the presentation of results from recent excavations performed by the first author. Formatted Formatted Formatted
Use of Geosynthetic Clay Liner as a Waterproofing Barrier in Sanitary Landfills
Journal of Urban and Environmental Engineering
One of the main sources of soil and water (superficial and subterranean) contamination is the inadequate solid waste disposal. In this sense, sanitary landfills have great importance for environmental protection, and in these systems, the geosynthetics materials, such as the Geosynthetic Clay Liner (GCL), are widely employed. However, for landfills with leachate recirculation, the application of GCL is vetoed by many government agencies. In view of this, this study sought to provide an analysis of recent advances in application of GCL in landfill sites. For this reason, the main configurations of landfills and characteristics of its leachate were presented, as well as of the GCL by means of case studies applied to the context. The results indicated that the most important parameter to be evaluated in GCL performance is its hydraulic conductivity, which can be influenced directly by leachate composition (conventional and recirculated) as to the presence of cations and anions. Thus, i...
The paper presents methods of laboratory and in situ tests as well as the results obtained, of the hydraulic parameters of the bentonite material used for the cutoff wall construction on the sanitary landfill site. It is assessed if there are any changes of permeability in time and how effective is the proposed material (self hardening cement-bentonit mixture). The procedures for the monitoring and contaminants migration modelling, and also the reliability of results are assessed and presented. It is proved that correctly installed vertical barrier made of bentonite material is a perfect solution for the old landfill reclamation and restoration works.
International Agrophysics, 2015
A b s t r a c t. This paper presents studies concerning the applicability of two clay materials for the construction of a sustainable landfill liner. The studies consisted in determination of basic characteristics of the materials, eg particle size distribution, bulk density, particle density, total porosity, pore size, mineralogy, specific surface area, nanoparticle size, and Atterberg limits, as well as measurements of their geotechnical and hydraulic parameters, such as in situ saturated hydraulic conductivity, modules of primary and secondary compression, cohesion, and angle of internal friction. Furthermore, the effects of compaction performed by the Proctor method at various water contents on swelling and shrinkage characteristics and saturated hydraulic conductivity were investigated in order to determine the compliance with the national requirements for selection of material for landfill liner construction. The determined characteristics and geotechnical parameters of the tested clay materials allowed qualifying them as suitable for municipal landfill construction. The shrinkage potential of the tested clays observed was rated as moderate to very high. The cyclic drying and rewetting of the clay materials performed resulted in a significant increase in saturated hydraulic conductivity. Thus, the clay sealing layers, as part of a multilayer liner, should be very carefully operated, preventing the drying out of the clay sealing and assuring the possibility of its constant saturation.
The Potential of Marine Clay Used for Landfill Liner: A Geotechnical Study
International Journal of GEOMATE
The increase in excessive solid waste due to the rapid growth of the world's population is considered a severe environmental problem. The landfill leachate will contaminate groundwater, putting all living things at risk. Natural clay is a common liner material used to keep landfill leachate from polluting the environment. This study investigates the geotechnical properties of natural marine clay and its potential to be used as a landfill liner. To investigate the soil properties, the Sungai Besar marine clay (SBMC) was subjected to physico-chemical, morphology and mineralogy properties including particle size distribution, specific gravity, atterberg limits, compaction, permeability, pH, organic content, cation exchange capacity (CEC), specific surface area (SSA), X-Ray Diffraction (XRD) and scanning electron microscope (SEM). Batch Equilibrium Test was conducted to determine the effectiveness of SBMC in adsorbing heavy metals (Pb 2+ , Cu 2+ , Co 2+ , Cd 2+ , Ni 2+ , Zn 2+). Results showed SBMC has a high percentage of fine grain size (silt 73-87% +clay 12-19 %), lower value of specific gravity (2.14-2.29), high liquid limit (79.50-84.00%), plasticity limit (49.18-59.35 %), plasticity index (20.15-34.22 %) and was categorized at very high plasticity in plasticity indexed chart. The SBMC also has maximum dry density value (1.36-1.37 g/cm 3), optimum moisture content, wopt (34.55-37.97 %) and average hydraulic conductivity (6.35 x 10-7-6.88 x 10-7 m/s). The chemical properties of the SBMC1 showed it has a high pH value (6.95-7.42), organic matter (5.31-6.06 %), CEC (91.25-92.32 meq/100g), and SSA value (60.28-62.38 m 2 /g). The XRD results showed that kaolinite, and illite were the most prevalent clay minerals, with quartz as the non-clay mineral. SEM analysis also revealed that kaolinite and microfossils were within the SBMC. The Batch Equilibrium test also showed that SBMC in single solution exhibited higher sorption for Cu (Kd= 0.4499 L/g, R 2 =0.98), followed by Pb (Kd= 0.3701 L/g, R 2 =0.85), Co (Kd= 0.3232 L/g, R 2 = 0. 0.88), Ni (Kd= 0.1483 L/g, R 2 =0.98), Zn (Kd= 0.0711 L/g, R 2 = 0.93) and Cd (Kd= 0.0627 L/g, R 2 = 0.98). Based on physico-chemical, mineralogy and morphology results, SBMC is an excellent choice acting as natural clay-based energy material to be used as an engineered clay liner in a landfill area.
Environmental and Sustainability Indicators, 2023
Liners are provided under engineering landfill sites to block the downflow of leachates and their noxious components to minimize pollution in the underlying aquifers or neighboring water bodies. Compacted clays are widely employed as suitable materials for constructing landfill liners because of their low hydraulic conductivity, balanced swelling potentials, and appropriate compressive strength. However, the quality has to be improved if the locally available soil does not meet the minimum standards for constructing liner materials. Including bentonite dosage with local soil can show better stability and strengthened cohesion bonds between molecules. This paper aims at a recent study on specific geotechnical properties of bentonite amended local Khulna clay soil intended to be used as a liner material. Bentonite in varying proportions (e.g., 5%, 10%, 15%, and 20%) was mixed with local soil, and specific tests (e.g., compaction tests, consistency tests, hydraulic conductivity tests, free swell tests, unconfined compressive strength tests, and pH tests) were conducted on the mixtures. Results indicated that the optimum moisture content (14.03%-19.30%), liquid (35.39%-53.98%), plastic (22.20%-35.23%), plasticity index (13.19%-18.75%), pH (7.23-7.43), swell index (3.13%-24.2%) and unconfined compressive strength (156.21 kPa-244.46 kPa) increased while bentonite was in conjuncture with the soil. In contrast, maximum dry density (17.80 kN/m 3 to 16.80 kN/m 3) and hydraulic conductivity (2.39 × 10 − 7 cm/s to 0.09 × 10 − 7 cm/s) decreased. Also, at 10% bentonite content, the mixture matched the acceptable standards for liner construction (hydraulic conductivity 0.29 × 10 − 7 cm/s <10 − 7 cm/s, and unconfined compressive strength = 210 kPa > 200 kPa).The study identified that adding bentonite to local soil can improve its geotechnical properties, making it a suitable material for landfill liners with increased strength and decreased hydraulic conductivity.
Geotechnical and Geological Engineering, 2017
Sanitary landfills are waste disposal method that functions without creating nuisance to the environment. It confines waste to the available area, reduce waste to the minimum practical volume. The waste in a landfill reacts to release a cocktail of contaminants called leachate, which posses treat to the surrounding environment (soil and groundwater). Therefore, barrier soils are required for the lining of a landfill to prevent seepage of leachate into the surrounding groundwater and subsequent contamination of the groundwater system. Some clay in Minna was assessed using geotechnical techniques to determine its suitability as barrier soils. Five samples of clay were subjected to grain size analysis, atterberg limits, compaction tests and mineralogy test. From the grain size analysis and the atterberg limit, the soil is classified as a clayey material. The liquid limit ranged from 45.5%-61% with a mean value of 51.8% which is an indication of high plasticity and low hydraulic conductivity, the plastic limit ranged from 29.2%-35.8% with a mean value of 32.44% and its plasticity index ranged from 13.7%-25.2% with a mean value of 19.37% which implies that the clay can withstand volumetric shrinkage on drying and exhibit a low to medium swelling potential when wet. The compaction test reveal an optimum moisture content(OMC) ranging from 17.7% to 24% with a mean value of 19.94% and a maximum dry density (MDD) that varied from 1.59g/cm 3 to 1.76g/cm 3 with a mean value of 1.7g/cm 3. This results of these geotechnical analysis suggests that the clay in the area meets the requirement for a barrier soil. The X-ray diffraction analysis reveals the presence of kaolinite dominated clay and mixed clay (kaolinite-illite). These minerals have the capability to attenuate and contain leachates from wastes. Hence, the studied clays are good barrier soils.
Geotechnical Characterisation of Marine Clay As Potential Liner Material
Sains Malaysiana
Natural clay is commonly used as a liner material to contain landfill leachate from contaminating the environment. A key characteristic of liner material is its hydraulic conductivity. It is recommended that the hydraulic conductivity of the potential liner material should be of 1×10 -9 m/s or less. This paper presents the geotechnical characteristics of marine clay that may be used as landfill liner material. The tests were consistency index, compaction behaviour, compressibility and hydraulic conductivity. The marine clay was dominated by finer fraction of silt and clay (78%-88%) followed by sand (12%-22%). The clay minerals commonly present were montmorillonite, kaolinite and illite as well as quartz as the non-clay mineral. The consistency index for the liquid limit, w L and plastic limit, w P were 56.6%-80.5% and 36%-45%, respectively. The plastic index, I p of the marine clay samples ranged from 19% to 37%. The permeability test indicated that the hydraulic conductivity of the...
Effect of Chemicals on Geotechnical Properties of Clay Liners: A Review
Research Journal of Applied Sciences, 2010
This study presents a review of recent research on the geotechnical properties (consistency limits, hydraulic conductivity, shear strength, swelling, and compressibility) of clay liners conducted with organic and inorganic chemicals. Due to its low permeability, a clay liner is the main material used in solid waste disposal landfills. It is exposed there to various chemical, biological and physical events, and the clay liner is affected by the resulting leachate. The geotechnical properties of clay liners are closely related to the chemistry of the leachate. Therefore, when attempting to define the geotechnical characteristics of clay liners, the use of distilled water or tap water is far from being representative of the in-situ conditions.
Geotechnical Evaluation of Bentonite Clay for Municipal Solid Waste Landfill Lining Membrane
2018
Evaluation method for 1 kg each of the three clay samples collected from Okada, Okpila and Oduna in Edo state, Nigeria, included elemental composition, and geotechnical methods such as attergerg limit test, grain size analysis and consolidated test method according to British Standard (BS) Code 1377. Considering ASTM standard requirement for landfill compacted clay liner, the sample collected from Oduna met the requirement with hydraulic conductivity of 1.077x10-7, liquid limit of 50.2%, plasticity index of 31% and 54.8% grain particles passing through #200 sieve size. The accuracy of the geotechnical evaluation was confirmed by using 50.2% liquid limit of 1 kg Oduna clay as 1 m thickness in the prototype landfill base and side walls, of which no shrinkage and desiccation cracking occurred upon drying. This is possibly due to the substantial percentage of Al2O3 (73.35%), SiO2 (18.80) and MgO (4.51%) in the clay crystal structure which primarily constitutes smectite.