Volumetric shrinkage of compacted soil liner for sustainable waste landfill

One of the main principal sources that contributes to the release of leachates in the environment is the municipal solid waste in landfill facilities. To mitigate the negative effects of leachate, landfill liner is constructed to provide a protective barrier that will not allow the leachate to pass through the compacted soil, which may cause groundwater contamination. Due to seasonal variation in tropical regions, compacted or natural soil liners tend to lose moisture when dry. This result to volumetric shrinkage, which causes cracks that affect the engineering properties and performance of the soils. Groundwater can easily be affected by leachate permeating through these cracks in soils because of desiccation induced by volume change. This paper aims to evaluate the effect of fines content at various gradation and moulding water content on volumetric shrinkage property of compacted laterite soil; and to compare the results with the regulatory standard for compliance to mitigate the negative effects of leachate on the environment. The technique used in this study was to vary the gradation of laterite soil at different moisture contents to achieve a sustainable result. It is observed that the volumetric shrinkage increase as the percentage of fines content increase with corresponding water content. The changes in volumetric shrinkage with time shows a sharp increase within the first five to ten d of drying and then become constant. The soil needs to be compacted on the dry side of optimum moisture content or at the optimum moisture content in order to meet the regulatory criteria of ≤ 4 %

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

Investigation of aqueous and non-aqueous phase liquid migration in double-porosity soil using digital image analysis

The development activity of the country has played a part in climate change and natural disasters, which lead to a negative influence on the geo-environment and health. The issues of leakage and spillage of Non- Aqueous Phase Liquids (NAPLs) and Aqueous Phase Liquids (APLs) contribute to groundwater contamination, resulting in groundwater pollution and rendering the quality of groundwater unsafe for drinking and agriculture. Ensuring availability and sustainable management of water and sanitation for all were the goal and target of the 2030 United Nations agenda for sustainable development, consisting of a plan of action for people, planet and prosperity. This paper investigates the aqueous and non-aqueous phase liquid migrations in the deformable double-porosity soil, which has become important for sustainability of groundwater utilisation and a comprehensive understanding of the behaviour of liquid migration into the groundwater. An experiment model was conducted to study the pattern and behaviour of aqueous and non- aqueous phase liquid migration in deformable double-porosity soil using digital image processing technique. The results of the experiments show that the flow of the APL and NAPL migration was not uniformly downward. Faster migration occurs at the cracked soil surface condition compared to other locations on the soil surface that were not cracked, even when not using liquid such as toluene. The factors that significantly influence the APL and NAPL migration are the structure of the soil sample, fracture pattern of the soil sample, physical interaction bonding between the liquid and soil sample, and the capillary pressure of the fluid. This study indicates that digital image analysis provides detailed information to facilitate researchers to better understand an d simulate the pattern of liquids migration characteristics as well as to ensure sustainable consumption of groundwater

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

Effects of fines content on hydraulic conductivity and morphology of laterite soil as hydraulic barrier

Laterite soil was investigated to find out the effects of fines content and to identify the micro-structural and molecular characteristics to evaluate its potentiality as a compacted soil landfill liner material. Tests were carried out on natural soil and reconstituted soil by dry weight of soil samples to determine the physical and engineering properties of the soil. All tests were carried out on the samples by adopting the British Standard 1377:1990. The possible mechanisms that contributed to the clay mineralogy were analyzed using spectroscopic and microscopic techniques such as field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) and X-ray diffractometry (XRD). The laterite soil was found to contain kaolinite as the major clay minerals. A minimum of 50% fines content of laterite soil met the required result for hydraulic barriers in waste containment facilities

Effects of fines content on hydraulic conductivity and morphology of laterite soil as hydraulic barrier

Laterite soil was investigated to find out the effects of fines content and to identify the micro-structural and molecular characteristics to evaluate its potentiality as a compacted soil landfill liner material. Tests were carried out on natural soil and reconstituted soil by dry weight of soil samples to determine the physical and engineering properties of the soil. All tests were carried out on the samples by adopting the British Standard 1377:1990. The possible mechanisms that contributed to the clay mineralogy were analyzed using spectroscopic and microscopic techniques such as field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) and X-ray diffractometry (XRD). The laterite soil was found to contain kaolinite as the major clay minerals. A minimum of 50% fines content of laterite soil met the required result for hydraulic barriers in waste containment facilities

Experimental study on aqueous phase liquids migration in double-porosity soil under non-isothermal effect using digital image analysis

Aqueous phase liquid (APLs) leakage and spillage into the subsurface system, leading to groundwater contamination is an issue that needs to be addressed. This paper aims to investigate the APLs migration characteristics in fractured non-isothermal double-porosity soil. A laboratory experiment was conducted to observe and monitor the characteristics of the soil structure and APLs migration in heated deformable double-porosity soil using digital image processing technique. The results show rapid liquid migration for the fractured soil samples. The time taken for the liquid to migrate under the application of heat is less for sample with low moisture content due to faster dry off and rapid evaporation. It can be concluded that APLs migration under vibration and non-isothermal effect is highly influenced by the soil sample structure, the soil fractured pattern, the soil water content, and the applied heat in the soil

Experimental study on aqueous phase liquids migration in double-porosity soil under non-isothermal effect using digital image analysis

Aqueous phase liquid (APLs) leakage and spillage into the subsurface system, leading to groundwater contamination is an issue that needs to be addressed. This paper aims to investigate the APLs migration characteristics in fractured non-isothermal double-porosity soil. A laboratory experiment was conducted to observe and monitor the characteristics of the soil structure and APLs migration in heated deformable double-porosity soil using digital image processing technique. The results show rapid liquid migration for the fractured soil samples. The time taken for the liquid to migrate under the application of heat is less for sample with low moisture content due to faster dry off and rapid evaporation. It can be concluded that APLs migration under vibration and non-isothermal effect is highly influenced by the soil sample structure, the soil fractured pattern, the soil water content, and the applied heat in the soil

Observation of light non-aqueous phase liquid migration in aggregated soil using image analysis

Physical model experiments were conducted to observe the migration of light non-aqueous phase liquids (LNAPL) in a double-porosity soil medium. The double-porosity characteristics of the soil were simulated through aggregation of kaolin which resulted in well-defined intra-aggregate and inter-aggregate pores. Digital images were collected to monitor LNAPL (modeled by toluene) migration. A special experimental setup was developed to enable the instantaneous capture of the LNAPL migration around the whole soil column using a single digital camera. An image processing module was applied to the captured images and the results plotted using a surface mapping programme. Events observed during the duration of the experiments were discussed. It was found that the LNAPL flowed much faster in the aggregated soil as compared to a single-porosity soil. The wettability of the fluid and the capillary pressure characteristics were demonstrated to be influential factors in immiscible fluids migration when the soil fabric showed highly contrasting porosity values

Use of digital image technique to study leachate penetration in biocemented residual soil

Recently, biocementation has become a trend of soil improvement. Nevertheless, few studies were conducted in its application to improve engineering properties of fine-grained soil. In this study, digital image technique (DIT) was employed to determine the effect of biocementation via enzymatic induced calcium carbonate precipitation (EICP) technique on the leachate penetration pattern and medium-term hydraulic conductivity of the compacted residual soil made from fine-grained soil. The findings have shown that the of leachate penetration pattern and hydraulic conductivities of the EICP treated soils were considerably affected by the formation of biocementation or CaCO3precipitation. It was found that the rate of leachate penetration was faster within the first 14 days of the test. It was also determined that at the end of 28 days, the amount of leachate penetrated the untreated soil, 0.50 M, and 1.0 M EICP treated soils were 14.16 mm, 10.08 mm, and 6.03 mm, respectively. The results have shown that EICP treatment resulted in the reduction of hydraulic conductivity by 28. 28.83% and 41.33% in 0.50 M and 1.00 M treated soils, respectively