Crack formation behavior of composite fly ash – bentonite (FAB) in landfill liner system

This study aims to investigate the influence of different mixtures on the phenomenon of desiccation cracking in bentonite-fly ash mixtures as a landfill liner system. Fly ash is quite potential to be used as a landfill liner mixture because it has a low hydraulic permeability or conductivity value. This study uses class F fly ash from the Paiton power plant production process, Indonesia, which has been distributed commercially. Desiccation test was conducted in this study. The composition of fly ash and bentonite which is used are pure fly ash (FAB0), fly ash and bentonite 15% (FAB15), fly ash and bentonite 20% (FAB20) and fly ash and bentonite 25% (FAB25). The smallest CIF value is found in the pure fly ash layer. However, the pure fly ash cannot be used as landfill liner because the high permeability value. Therefore, the addition of bentonite will increase the possibility of crack formation. This study reveals that the addition bentonite in the fly ash composite will increase the crack. However, determining appropriate mixture composition is critical when working on the landfill liner system.

Stability performance of demolition waste composite as landfill liner

Landfill liner is one of the essential components that prevent leachate infiltration of the soil from causing pollution. A liner has specific design criteria to function optimally. This study analyses the permeability and stability value of the mixture of composite materials consisting of demolition waste, bentonite, and lime materials. This study using some methods include falling head method for permeability test and direct shear strength for stability test. Based on the results of this research, it can be seen that the mixture of demolition waste and bentonite to composite can reduce the internal shear angle and increase the cohesion. While lime provides a fluctuating value for cohesiveness, it can increase the internal shear angle. The best mixture to be used as an alternative composite liner is the V6 composite which has a demolition waste composition of 79%, 20% bentonite, and 1% lime with a permeability coefficient value of 8.526 × 10−7 cm/s.

The effect of demolition waste composition on the landfill liner physical characteristic

This study analyses the physical characteristics of demolition waste on the composite landfill liner. In this study, three characteristic composite landfill liner tests consist of swelling/specific gravity, OMC standard proctor determination, and atterberg limit test. Composite landfill liner consists of demolition material, bentonite, and lime with eight variable samples. Based on this research, specific gravity ranges from 1.8-2.1 g/cm3, OMC’s highest is V7, and MDD’s lowest is 1.81 g/cm3. Demolition waste content is below 80% can be carried out atterberg limit test. It is related to the particle size distribution test, which states that the size of demolition waste is a type of sand.

Suitability of Shale Treated with Palm Kernel Shell Ash and Pulverized Palm Kernel Shell As Landfill Liners at Nguzu Edda, Southeastern Nigeria

Wastes are mostly disposed of in landfills, which pose threat to soil and groundwater as a result of percolation of leachate. Therefore, barrier soils are required for the lining of a landfill to prevent seepage of leachate into the surrounding groundwater system. In this regard, the suitability of ten shale samples treated with 0-12 % (increments of 2 %) proportion of palm kernel shell ash (PKSA) and pulverized palm kernel shell (PPKS) by dry weight of the shale samples were evaluated for uses as landfill liner. The samples were subjected to series of geotechnical tests to determine the index properties, and strength characteristics of the natural and treated shale using West African standard (WAS) and Modified AASHTO (MAS) compactive energy levels for comparison purposes. The shale was classified as A-7-5. The atterberg limits test results show that liquid and plastic limits generally decreased, while the plasticity index (PI) increased with increase in PKSA and PPKS contents. The results also demonstrated that maximum dry density (MDD), volumetric shrinkage strain (VSS) and hydraulic conductivity decreases significantly while optimum moisture content (OMC) increases with increase in PKSA and PPKS contents for the both energy levels. The maximum strength of 380.30 and 448.70 KPa were recorded at 4 % of the stabilizers. The findings affirmed that the samples met the requirements for landfills liner, although PPKS was more effective than PKSA for both energy levels. Moreover, the addition of PKSA and PPKS to liners can also be an alternative means of its disposal.

A Study to Understand Reduction Behavior of Toxic Metal in Leachate Using Bentonite

Landfills are the most popular municipal solid waste disposal system. The landfill liner is designed to isolate the waste from the soil beneath to minimize the passage of leachate into the groundwater. Usually, compacted liner materials consist of soil rich in clay minerals for their low hydraulic conductivity. This study is an attempt to assess the use of bentonite as a potential liner material. With the addition of bentonite in landfill liner, the toxicity of leachate is expected to decrease. It was found that bentonite bed works as a shield against percolation of heavy toxic metals from leachate of landfills into soil and groundwater.