Hydraulic Conductivity Characteristics of a Fine-Grained Soil Potential for Landfill Liner Application

Abstract

Sanitary landfills (SLFs) are usually employed as final waste disposal facility to protect public health and the environment. As a result of rapid population growth and urbanization, there is currently a great demand to construct SLFs in the Philippines. The hydraulic conductivity characteristics of remolded samples of a locally abundant fine-grained soil compacted at different compaction energy level is investigated to determine the suitability of the soil as landfill liner material. The hydraulic conductivity of lining system is one very salient feature of the SLF to prevent contamination of nearby soil and water sources. The physical properties of the soil are determined through a series of laboratory tests which includes the grain-size distribution, specific gravity, Atterberg limits, soil classification, Cation Exchange Capacity (CEC), X-ray powder diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). The falling head laboratory test was conducted to determine the saturated coefficient of hydraulic conductivity. A numerical model was formulated that can predict hydraulic conductivity as a function of the void ratio. The resulting coefficient of hydraulic conductivity ranges from 1.98 x 10 -6 to 1.0 x 10 -7 cm/sec meet the Philippine standard requirement. The soil being classified as clay loam can readily be used as top lining material. However, additional study on unconfined compressive strength and volumetric shrinkage among other parameters is recommended prior to use of the fine-grained soil as bottom lining material as soil amendment maybe necessary.

Effectiveness of Compacted Polyurethane-Clay as a Sanitary Landfill Liner

“…Thus, five trials were conducted to approximate the compaction moisture content that would yield an acceptable hydraulic conductivity of the compacted local clay. In which, the trial specimen for this study was targeted to have a similar hydraulic conductivity with the specimen from the study of Tiongson and Adajar [7,8] that used the same type of expansive soil from the same site in Kauswagan, Lanao del Norte. The compaction moisture content established from the trial tests was 46.5%, which was used in the mix proportion of the specimens used in the experimentation to obtain the hydraulic conductivity of the compacted polyurethane-clay.…”

“…The summary of the initial void ratio and the description of the manual compactive effort applied for the three kinds of compacted specimen are tabulated in Table 5. The compactive effort that produced the CCL, with an initial void ratio of 1.06, compaction moisture content of 46.5%, and an acceptable hydraulic conductivity based on the study of Tiongson and Adajar [7,8] that used the same type of soil, was applied to polyurethane-clay that produced the CPCL. CPCL had the same compactive effort as CCL, but a higher initial void ratio of 1.44.…”

“…By utilizing the model proposed by Tiongson and Adajar [7,8] to predict the hydraulic conductivity for the same local clay, the compactive effort of the manually compacted specimen in the study may be determined. The actual hydraulic conductivity of CCL is similar to the predicted value for specimen in which the Standard Proctor effort of 600 kN-m/m 3 was applied as the compactive effort.…”

Shear Strength and Durability of Expansive Soil Treated with Recycled Gypsum and Rice Husk Ash

“…Mendoza et al [8] revealed that smectite in Manila indicates moderate to high plasticity indices and low hydraulic conductivity values ideal for landfill lining. Research by Tiongson and Adajar [9] on compacted clay linings was conducted in response to the imminent operation of a sanitary landfill in Kauswagan, Lanao del Norte, and nearby municipalities. Local soil samples intended as landfill lining material were identified as expansive soils.…”