Waste Containment Applications Research Articles

Hydraulic conductivity of two geosynthetic clay liners with different bentonite granule sizes

Experiments were conducted to evaluate the hydraulic conductivity of two commercially available geosynthetic clay liners (GCLs) with similar properties but different bentonite granule sizes (D50=1.0 mm or 0.3 mm). A synthetic municipal solid waste (MSW) leachate prepared in the laboratory and four actual coal combustion product (CCP) leachates collected from the field were used as permeant solutions to represent different permeant chemical conditions for waste containment applications. The two GCLs had comparable hydraulic conductivity to dilute or moderate ionic strength (I) leachates (< 0.1 M). With more concentrated leachates (I > 0.1 M), hydraulic conductivity of the GCL containing finer bentonite granules (FG) was 10 to 500 times lower than the hydraulic conductivity of the GCL containing coarser bentonite granules (CG) under the same equilibrium conditions. These results suggest that GCLs containing finer bentonite granules may be less vulnerable to permeant chemistry.

Coupled Effect of Cementation Solution, Curing Period, Molding Water Content, and Compactive Effort on Strength Performance of Biotreated Lateritic Soil for Municipal Solid Waste Containment Application

Microbial-induced calcite precipitation (MICP) is a soil improvement technique that has shown great potential in several geotechnical applications in the previous decade. Some factors that led to the improved strength included cementation concentration. The combined influence of these factors with the cementation reagent was paramount to the calcite precipitation level within soil grain contact of a biotreated compacted fine-grained soil. In this study, the influence of the concentration of the cementation solution [(CCS) 0.25, 0.5, 0.75 and 1.00 M], curing time [(CT) 24 h, 3, 7, 14, and 28 days], and molding water content [MWC (9.8%–19.6%)] of biomediated lateritic soil or lateritic soil that was bioinfused with ureolytic microbes at different suspension densities (cells/mL) and compacted with Reduced British Standard Light (RBSL), British Standard Light (BSL), West African Standard (WAS), and British Standard Heavy (BSH) energy, respectively, were evaluated. In addition, this study focused on unconfined compressive strength (UCS). The results showed an increased UCS with the corresponding average calcite content up to peak values at 0.5 M cementation concentration for the five considered bacterial cells/mL. In addition, the results showed a linear relationship between UCS and average calcite content for the CCS that were considered. The effect of the curing period on UCS was marginal within individual cementation concentrations regardless of bacterial cells/mL. The UCS of the specimen that contained the optimal 0.5 M cementation concentration increased with higher bacterial cells/mL but decreased with the MWC. The qualitative microanalysis that used scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses that evaluated the untreated and biotreated specimens showed the formation of calcite, which increased the soil strength by blocking the soil pores through grain–grain contacts.

Evaluation of Geotechnical Properties of Black Cotton Soil Reinforced with Sisal Fibre for Waste Containment Application

Compacted Black Cotton Soils (BCS) used in geotechnical constructions such as dams and clayey liners in waste containment facilities can suffer from cracking due to swelling and shrinking during wet and dry seasons respectively. In order to reduce the shrinkage of the clayey soil, discrete fibre reinforcement such as the Sisal Fibre (SF) technique was used. An experimental study was carried out on the natural and the modified properties of the soil which include Atterberg limits, compaction, Unconfined compressive strength UCS (i.e., for varying Moulding Water Content (MWC) relative to Optimum Moisture Content (OMC); OMC-2, OMC, OMC+2, OMC+4) and Volumetric Shrinkage Strain (VSS) at MWC relative to OMC; (OMC-2, OMC, OMC+2, OMC+4) were determined, for different percentages inclusion of sisal fibre (0, 0.5, 1, 1.5 and 2% SF). Results obtained show that the liquid limit and plasticity index of the natural soil are 44.47% and 18.65% which increased with an increase in the sisal fibre content. OMC increased from a value of 19% for the natural soil to a peak value of 24.5% at 1.5% of sisal fibre and thereafter decreased. The natural soil has a Maximum Dry Density (MDD) of 1.55 Mg/m3 which decreased to 1.5 Mg/m3 at 1.5% additive. The VSS of the modified soil significantly decrease compared to the natural soil and it continually decreased as the percentage of sisal fibre increased. The lowest VSS values were observed at 2% SF, having values of 2.85, 3.5, 4.75, and 5.5% for OMC-2, OMC, OMC+2, and OMC+4, respectively. The UCS initially increased and thereafter decreased. Based on the results, soil optimally treated with a maximum of 0.5% sisal fibre and compacted with OMC-2 significantly improved the soil and is recommended for use in waste containment applications.

Unsaturated hydraulic conductivity of compacted bio-cemented lateritic soil in municipal solid waste containment application

Most engineering infrastructures, including municipal solid waste containment facilities, are situated in unsaturated zone. The use of chemical additives for soil improvement has been linked to the adverse environmental issues being experienced globally. Research into more sustainable methods of soil improvement has led to the discovery of a novel and innovative method known as microbial induced calcite precipitation (MICP). Lateritic soil was treated with stepped Sporosarcina pasteurii (S. pasteurii) suspension density up to 2.40 x 109 cells/ml at moulding water content (MWC) -2, 0 and +2 % relative to optimum moisture content (OMC) before compaction using Reduced British Standard light (RBSL), British Standard light (BSL), West African Standard (WAS) or Intermediate and British Standard heavy (BSH) energies. Compacted specimens were saturated with cementation reagent in three cycles with 1/3rd pore volume at 6 hours’ interval to induce calcite precipitation at an ambient laboratory temperature of 24±2°C. The soil-water characteristics curves (SWCC) of the specimens were determined using pressure plate extractor over a pressure range of 10-1500 kPa. Unsaturated hydraulic conductivity values were predicted for the S. pasteurii suspension densities considered using Brooks-Corey, van Genuchten as well as Fredlund and Xing curve fitting prediction models. Results show that the unsaturated hydraulic conductivity values of specimens prepared at lower, MWC relative to OMC were generally higher than at higher MWC regardless of compactive efforts and S. pasteurii suspension densities considered. The Brooks-Corey model gave the best predicted unsaturated hydraulic conductivity values which fit the requirements for waste containment facilities over the matric suction range and S. pasteurii suspension densities considered, than the van Genuchten and Fredlund – Xing, when compared with measured values.

Development of expansive soil geopolymer binders for use in waste containment facility

Waste containment facilities require liners and covers for safe waste disposal, which can be efficiently achieved using robust green technologies. In the present study, a systematic approach was adopted towards the development of reliable expansive soil geopolymers suitable for waste containment application. Various factors that influence geopolymerisation were considered including the precursor type (PT), precursor content, liquid alkali hydroxide type (LT), activator-to-precursor ratio (A/P) and method of preparation. Multiresponse optimisation for permeability, volumetric shrinkage and unconfined compressive strength was executed to achieve soil geopolymers that satisfy the regulatory requirement as hydraulic barrier materials. This was done using a robust experimental design and the utility concept to prescribe a framework for achieving reliable soil geopolymers. The results obtained show that significant interactions between the factors (PT × LT) and (PT × A/P) affected the response characteristics and consequently the soil geopolymer performance. The aptness of the multiresponse optimisation was confirmed at 95% confidence interval, which revealed that the developed soil geopolymers can be used in waste containment facility under certain conditions. Evidence of the geopolymerisation process was clarified using microstructural analyses. Scanning electron microscopy and energy-dispersive spectroscopy supported the formation of N–A–S–H and K–A–S–H gels. Moreover, diffraction patterns for new minerals such as muscovite and crystobalite were formed, with the disappearance of clay minerals. The presence of aluminosilicate gel binding systems was revealed by Fourier transform infrared spectroscopy. The participation of clay minerals in the geopolymerisation distinguishes the developed expansive soil geopolymer from the conventional geopolymers developed for concrete applications.

Adsorption characteristics of Barmer bentonite for hazardous waste containment application

Low hydraulic conductivity and high chemical immobilization are the two characteristics that make bentonite a mandatory construction material for hazardous waste containment applications. We performed a comprehensive batch sorption study on Barmer bentonite (BB), an exclusive construction clay mined in India, using lead (Pb2+) as a model contaminant. The maximum adsorption capacity of BB was obtained as 55 mg g−1 at pH 5 and 27 ± 2℃. Adsorption was extremely rapid, with equilibrium attained <5 min for the BB. Increased adsorbent dosage resulted in higher Pb2+ percentage removal, while adsorption capacity decreased. Ionic strength, salt concentration, valency and ionic radius played a critical role in suppressing the adsorption of Pb2+. Clay fabric change was observed to be dispersed at low ionic strength and gradually attained aggregated face-to-face structures at high ionic strength. The simultaneous presence of other metals/salts strongly influenced Pb2+ removal by BB, while divalent salt exhibited high suppression of adsorptive reaction at low concentrations. Sorption isotherm and kinetic modeling results indicated the possibility of chemisorption of Pb2+ on BB. Based on the thermodynamic analysis, it was noted that Pb2+ adsorption on BB is exothermic, spontaneous and adsorption reaction is less favorable at a higher temperature.

Enhancement of Clay–Sand Liners Using Crushed Limestone Powder for Better Fluid Control

Tunnel boring machine (TBM)-crushed limestone material is a fine powder obtained during tunnel excavations. This material is proposed for use as smart filler in clay–sand liners, which include highly plastic clay and are typically used in waste containment applications and other fields. Replacing a part of bentonite in these liners with an inert, low plasticity material is an efficient way of controlling the compressibility and reducing the swelling index. The objective of this study was to test the water retention capacity under various mixture conditions. The soil–water characteristic curves for mixtures consisting of sand and 15% clay were investigated with regard to three main proportions: clay mixture consisting of one-third of TBM powder and two-thirds of bentonite, clay mixture consisting of two-thirds of TBM powder and one-third of bentonite, and a mixture consisting of only sand and bentonite. The geotechnical properties exhibited a clear improvement in the compressibility and swellability of the clay–sand liner owing to the addition of TBM-crushed limestone filler. The clay–sand mixtures were enhanced by adding crushed filler and could seal off the pores and voids, retain a satisfactory hydraulic conductivity, and prevent or minimize the flow through the layer. Scanning electron microscopy and X-ray investigations were performed for the TBM limestone powder material mixed with commercial bentonite.

Numerical modeling of leachate migration in compacted tropical laterite soil

To protect groundwater from leachate contamination in sanitary landfill involve the use of hydraulic barriers i.e. liners and covers. Nonetheless, can these barriers continue to impede the migration of leachate over a long period? A full-scale experiment would be prohibitively costly and time consuming. The only feasible recourse therefore is to construct a model, which reasonably portray the behaviour of the full-scale system and simulate the relevant physical parameters and describes the overall significant characteristics of the transport phenomena. This research investigates the long-term performance of compacted tropical laterite soil liners at various gradations against leachate migration in sanitary landfills using numerical modeling. Series of laboratory experimentation were carried out using three different laterite soil gradations (30%, 40% and 50% with respect to fines content) compacted at optimum moisture content using British Standard light energy. Leachate was poured on the compacted soil in an acrylic column and its migration was monitored using Digital Image Technique (DIT). Subsequently, PetraSim computer software a graphical interface used to solve problems related to contaminant transport was applied to predict the velocity of leachate migration. The predicted velocity values for 30%, 40% and 50% fines are 4.5 x 10−7 m/s, 7 x 10−9 m/s, and 8 x 10−10 m/s, respectively. This shows that the laterite soil with 50% fines content is more compatible with the leachate and can be used as soil liner. The outcome of this research would enable designers to use non-destructive method to monitor and predict leachate migration in compacted soil liners to simulate leachate migration in waste containment applications.

Lateritic Soil Treated with Waste Wood Ash As Liner in Landfill Construction

ABSTRACTInherent variability in engineering properties of lateritic soil in relation to its plasticity, permeability, strength, workability, and natural moisture content, has made it an unpredictable material for use in civil engineering works, resulting in the need for its treatment by stabilization. A lateritic soil classified as A-6(6) and CL, according to American Association of State Highway and Transportation Officials and Unified Soil Classification System of ASTM (2011), was treated with up to 10 percent waste wood ash (WWA). Compaction was carried out using four energies, namely, reduced British Standard light, British Standard light (BSL), West African Standard, and British Standard heavy, on samples, which were then examined for hydraulic conductivity, volumetric shrinkage, and unconfined compressive strength as major criteria for use as liner and for the development of acceptable zones. Specimens with 4 percent WWA content compacted with a minimum BSL energy satisfied the maximum hydraulic conductivity (k) value of 1 × 10−9 m/s, maximum volumetric shrinkage strain of 4 percent, and minimum unconfined compressive strength value of 200 kN/m2 required for use as liner in engineered landfills. The overall acceptable zone was enlarged for up to 4 percent WWA content, thereby accommodating higher moulding water content, but the minimum compactive effort required to achieve it became reduced. The beneficial treatment of lateritic soil with up to 4 percent WWA will perform satisfactorily as liner and covers in waste containment application and will minimize the pollution and environmental impact of wood waste disposal.

Monitoring Leachate Migration in Compacted Soil Using Digital Image Technique

As leachate has been a source of groundwater contamination worldwide, this paper examines the phenomenon of leachate migration on different gradations of compacted laterite soil used as sanitary landfill liners. Three different soil gradations (30%, 40% and 50% with respect to fines content) used in this study were compacted in circular acrylic columns to provide a clear visualization of leachate migration into the soils. Digital image technique was used in capturing photos at successive time intervals to monitor the leachate migration. The captured digital images were fed into Matlab and converted into hue-saturation-intensity (HSI) format. Surfer software then read the HSI and generated 2D contour plots. The results of the experiments showed that the leachate moves downward faster in the soil gradation with the least fines content. Hydraulic conductivity values decrease with increase in time duration and equally with increase in fines content. The hydraulic conductivities of the leachate for 30%, 40% and 50% fines were 3.64×10-9m/s, 2.40×10-9m/s, and 1.24×10-9m/s respectively. This reveals that for tropical laterite soils, gradation containing 50% fines content provides better hydraulic conductivity. The use of noninvasive digital image technique can enable designers/engineers to monitor and visualize the leachate migration in compacted soils in waste containment application systems.

EFFECT OF COMPACTIVE EFFORTS ON DESICCATION – INDUCED VOLUMETRIC SHRINKAGE STRAIN OF SOME COMPACTED TROPICAL SOILS

This paper presents an experimental study of the desiccation-induced volumetric shrinkage strain for two compacted soils classified as A (A-6) and B (A-7-6)according to the Association of American States Highway and Transportation Officials (AASHTO) Classification System and CL according to the Unified Soil Classification System (USCS). The samples were prepared using three compactive efforts of Reduced Proctor (RP), Standard Proctor (SP) and Modified Proctor (MP) at moulding water contents relative to optimum (i.e. -2, 0, +2 and +4%). Samples were extruded from the compaction moulds and allowed to air dry in the laboratory in order to assess the variation of desiccation-induced shrinkage on the material with days and its potentials as a hydraulic barrier in waste containment applications. Results showed that soils compacted using the higher compactive effort showed lower values of volumetric shrinkage strain (VSS) due to the closer packing of soil fabric as a result of higher energy. Similarly, VSS increased with higher moulding water content for specimens compacted on the wet side of the optimum and contain much water as against the specimens compacted on the dry side of the optimum which had less water. At 7 and 14 days cured specimens using the RP compactive effort showed similar features, and up to 2% on the dry side of the optimum for 0 and 21 days cured specimens. The SP compactive effort for 7 and 14 days cured specimens yielded the peak dry densities at 2% on the wet side of optimum and at optimum. The MP compactive effort, the samples compacted at 2% on the wet side of optimum and 2% on the dry side of optimum showed similar behaviours for the hydration periods of 0 to 14 days curing period considering soil sample A. For soil sample B, at 14 and 21 as well as 7 and 21 days cured specimens showed highest dry densities with similar features for, 2% on the wet side of optimum up to the optimum; but changes at 2% on the dry side of optimum for both RP and SP compactive efforts respectively. The predicted models measured adequately the estimation of VSS value using the analysis of variance (ANOVA) and gave good indication of validity.

Stress-controlled direct shear testing of geosynthetic clay liners I: Apparatus development

The use of geosynthetic clay liners (GCLs) in waste containment applications can induce long-term normal and shear stresses as well as expose GCLs to elevated temperatures and non-standard hydration solutions. Considering the importance of GCL internal shear strength to the design and integrity of waste containment barrier systems, innovative laboratory testing methods are needed to assess shear behavior of GCLs. There were two main objectives of this study: (i) develop a stress-controlled direct shear apparatus capable of testing GCLs exposed to elevated temperatures and hydrated in non-standard solutions; and (ii) assess internal shear behavior of GCLs under varying experimental conditions (e.g., stress, temperature, solution). These two objectives were partitioned into a two-paper set, whereby Part I (this paper) focuses on the shear box design and Part II focuses on an assessment of shear behavior. The direct shear apparatus includes a reaction frame to mitigate specimen rotation that develops from an internal moment within needle-punched reinforced GCLs. Rapid-loading shear tests were conducted to assess functionality of the apparatus and document baseline shear behavior for a heat-treated and a non-heat treated needle-punched GCL with comparable peel strength. These two GCLs failed at comparable applied shear stress; however, the heat-treated GCL yielded lower shear deformation and failure occurred via rupture of reinforcement fiber anchors, whereas the non-heat treated GCL yielded larger shear deformation and failure via pullout of reinforcement fibers.

Computer Modeling Approach of Leachate Flow in Compacted Laterite Soil Liner

The use of hydraulic barriers in sanitary landfills has become an impeccable means of protecting the groundwater system from leachate. A question to be asked is, can these barriers continue to impede the migration of leachate over a long period? This paper investigates the phenomenon of leachate migration in compacted laterite soil used as liner in sanitary landfills. An experiment was carried out using laterite soil compacted at optimum moisture content using Standard Proctor energy. Leachate was poured on the compacted soil in an acrylic column and its migration was monitored using Digital Image Technique (DIT). The DIT capture photographic images at successive intervals of time which were fed through an image processing code to convert them to hue-saturation-intensity (HSI) format with the help of Surfer and Matlab computer softwares. Subsequently, PetraSim computer software was applied to predict the velocity behavior. The predicted velocity value shows that the laterite soil is compatible with the leachate and can be used as soil liner. The outcome of this study would enable designers to use non-destructive method to monitor and predict leachate migration in compacted soil liners to simulates leachate migration in waste containment applications.

Standardized Hydraulic Conductivity Testing of Compacted Sand-Bentonite Mixtures

AbstractCompacted sand-bentonite mixtures can be used as engineered barriers (liners) for waste containment applications. A primary consideration for such applications is the ability of the mixtures to achieve a suitably low hydraulic conductivity, k, typically ≤1.0 × 10−9 m/s, based on permeation with water in the laboratory. The purpose of this study was to evaluate in a systematic manner the applicability of ASTM D5084-10 for the measurement of k of compacted sand-bentonite mixtures. Final degrees of saturation, Sf, for 4 of the 19 test specimens were outside of the required range 95 % ≤ Sf ≤ 105 %, even though the measured k values for these 4 specimens were consistent with those tested under the same conditions with values of Sf that met the standard. Thus, Sf apparently was an unreliable measure of true saturation for the materials tested in this study. Otherwise, the results indicated that conservatively high values of k were measured for the largest specimen size, the highest applied hydraulic gradient, and the highest ionic strength of the permeant water. A difference in the method of hydraulic gradient application had essentially no effect on the magnitude of k. Finally, as expected, specimens containing the highest amount of bentonite (i.e., 15 % by dry weight) resulted in the lowest values of k, although calculation of some values of k for one specimen were negative (k &amp;lt; 0), which was attributed to swelling of the specimen during permeation and the manner in which k was calculated based on ASTM D5084-10.

Desiccation-Induced Volumetric Shrinkage of Compacted Metakaolin-Treated Black Cotton Soil for a Hydraulic Barriers System

Abstract Black cotton soil treated with up to 24% metakaolin (MCL) content was prepared by molding water contents of −2, 0, 2, 4 and 6% of optimum moisture content (OMC) and compacted with British Standard Light (BSL) and West African Standard (WAS) or ‘Intermediate’ energies. The specimens were extruded from the compaction molds and allowed to air dry in a laboratory in order to assess the effect of desiccation-induced shrinkage on the compacted mix for use as a hydraulic barrier in a waste containment application. The results recorded show that the volumetric shrinkage strain (VSS) values were large within the first 10 days of drying; the VSS values increased with a higher molding of the water content, relative to the OMC. The VSS generally increased with a higher initial degree of saturation for the two compactive efforts, irrespective of the level of MCL treatment. Generally, the VSS decreased with an increasing MCL content. Only specimens treated with a minimum 20% MCL content and compacted with the WAS energy satisfied the regulatory maximum VSS of 4% for use as a hydraulic barrier.

The ISSMGE Kerry Rowe Lecture: The role of diffusion in environmental geotechnics

Diffusion of contaminants can play a significant if not dominant role in many applications encountered within the field of environmental geotechnics. The objective of this paper is to provide an overview of the important role diffusion plays in such applications. The presentation proceeds from a historical perspective, beginning with the recognition in the late 1970s to early 1980s that diffusion may be an important process in assessing contaminant migration through low-permeability barriers in waste containment applications. Data from the literature and simplified model simulations are used to illustrate under what conditions diffusion is important, and the significance of diffusion is illustrated with respect to different barrier components and types of barriers used in waste containment applications. The barriers considered include natural clays, compacted clay liners, geomembranes, geosynthetic clay liners, composite liners, vertical cutoff walls, subaqueous caps for contaminated sediments, and highly compacted bentonite buffers for high-level radioactive waste containment. The significance of semi-permeable membrane behavior on liquid-phase diffusion through bentonite-based barriers also is highlighted. The potential importance of matrix diffusion as an attenuation mechanism for contaminant transport is illustrated, and the roles of both liquid-phase and gas-phase diffusion under unsaturated conditions are discussed. Finally, the role of diffusion in terms of remediation applications is illustrated via an example analysis illustrating the impact of reverse matrix or back diffusion on the effectiveness of pump-and-treat remediation, as well as via a summary of several diffusion-based models commonly used to describe the leaching of contaminants from a variety of stabilized–solidified waste forms.

Electric–hydraulic–chemical coupled modeling of solute transport through landfill clay liners

Pollutant migration in dense clay barriers appears to be strongly influenced by the electric double layer of colloidal surfaces. Osmosis that resulted from chemical potential or electric potential difference across the clay membrane has been successively described in a number of theoretical works. Streaming potential (SP) which is present in charged porous medium under hydraulic gradient has been recognized as a significant factor governing the mass migration in compacted clays. However, few studies have been carried out in geo-environmental area with regard to this physical phenomenon. A coupled model was proposed to account for the effects of electrical, chemical and fluidic fields on solute transport in porous medium in this study. The electrical field deals with both the streaming potential and the externally applied electrical potential. The coupled nonlinear partial differential equations are numerically simulated by finite element method. Both the steady state solution and the time-dependent solution were investigated with the consideration of a series of influential factors. The streaming potential coefficient and the electro-osmotic coefficient were found to control the solute transport process. The potential application of the materials with tendency of producing SP was discussed. With appropriate selection of materials and parameters, optimum barring effect could be obtained for soil barriers in waste containment applications.

Evaluation of Lime Treated Oil Contaminated Soils for Use in Waste Containment Applications

This paper presents the results of an evaluation of lime treated oil contaminated soil for use in waste containment systems. Soil samples were treated with up 6 % lime contents. Specimens were prepared at optimum moisture content and compacted using British Standard Light (BSL) or Standard Proctor (relative compaction = 100%) to evaluate its effectiveness when used in waste containment applications. The hydraulic conductivity values increased with higher lime contents but were less than 1 x 10-9 m/s required for a liner material.

Hydraulic conductivity of three compacted reddish brown tropical soils

In developing countries groundwater is used for drinking and other beneficial purposes. However, its purity and quality is compromised because of the way waste is disposed. Laboratory tests were carried out to evaluate the hydraulic conductivity of three reddish brown tropical soils (labeled MP1-MP3) compacted at −2, 0, 2 and 4% of optimum moisture content using four compactive energy levels namely Reduced Proctor (RP), Standard Proctor (SP), West African Standard (WAS) and Modified Proctor (MP) and then permeated in compaction mould permeameter under falling head condition. Hydraulic conductivity values approached 1 × 10−7 cm/s at optimum molding water contents and up to 4% wet of optimum. This was achieved when the dry unit weight was greater or equal to 6.10 kN/m2 at initial degree of saturation of 84% and compactive effort which should not be lower than SP. The results obtained compare favorably well with existing literature database for hydraulic structures, thus showing the suitability of the material for waste containment application.

Evaluation of bagasse ash treated lateritic soil as a potential barrier material in waste containment application

Laboratory tests were conducted on a reddish-brown lateritic soil treated with up to 12 % bagasse ash to assess its suitability in waste containment barriers applications. Soil samples were prepared using four compaction energies (i.e. reduced Proctor, standard Proctor, West African Standard or ‘intermediate’ and modified Proctor) at −2, 0, 2 and 4 % moulding water content of the optimum moisture content (OMC). Index properties, hydraulic conductivity (k), volumetric shrinkage and unconfined compressive strength (UCS) tests were performed. Overall acceptable zones under which the material is suitable as a barrier material were obtained. Results recorded showed improved index properties; hydraulic conductivity and UCS with bagasse ash treatment up to 8 % at the OMC. Volumetric shrinkage strain increased with higher bagasse ash treatment. Based on the overall acceptable zone obtained, an 8 % optimal bagasse ash treatment of the natural lateritic soil makes it suitable for use in waste containment barrier application.