Effectiveness of Compacted Polyurethane-Clay as a Sanitary Landfill Liner

Abstract

Sanitary landfill is a waste disposal facility that has control over the potential impact of solid waste by using impermeable liners to prevent contamination of the environment. Several studies improved the impermeability of compacted clay liners by adding bentonite. However, bentonite is an expansive soil susceptible to volume change that would cause the deterioration of the sanitary landfill liner. Hence, the study aimed to investigate the effectiveness of compacted clay mixed with polyurethane as a sanitary landfill liner since polyurethane is a polymer known for its stability and impermeability. Through experimentation using a rigid wall permeameter, it was inferred that the hydraulic conductivity of the compacted polyurethane-clay is acceptable as a sanitary landfill liner. On the other hand, the compacted clay with the same initial void ratio as the compacted polyurethane-clay is not an acceptable landfill liner. Thus, the changes in the soil structure induced by adding polyurethane to the clay has a significant effect on the permeability characteristics.

Lateral Shrinkage of Compacted Polyurethane-Clay Subjected to a Single Wet-Dry Cycle

“…The clay utilized in the study was excavated at a depth of 2 meters in a proposed SLF site at Kauswagan, Lanao del Norte, which was also the same material used in the study conducted by Frianeza and Adajar [8]. Table 1 shows the index properties of the clay used in the study.…”

“…Table 1 shows the index properties of the clay used in the study. The same rigid polyurethane foam used in the study of Frianeza and Adajar [8] was used as a polymer soil-stabilizing agent. The rigid polyurethane foam was also purchased from Polymer Product (Phil.…”

“…A study conducted by Frianeza and Adajar [8] inferred that polyurethane clay is a suitable SLF liner material due to its low permeability. However, few studies have determined the lateral shrinkage of compacted specimens with polymer measured from a saturated state to a dry state.…”

“…The compaction moisture content of the specimen in the study is 46.5%, which is a wet of the optimum moisture content established in the study of Frianeza and Adajar [8]. The compaction moisture content was established through a series of trial and error, starting at the optimum moisture content to determine the corresponding moisture content that would yield a high relative compaction for the compacted clay.…”

“…The obtained compaction moisture content, 46.5%, was targeted to be within the varied moisture content in the study of Tiongson and Adajar [9], which ranges from 47.25% to 39.65%. Furthermore, the same compaction moisture content was also used in the study of Frianeza and Adajar [8], which yielded the same mix proportion tabulated in Table 3 to determine the lateral shrinkage. In addition, the ratio of the polyurethane used in the study is 1 part polyol and 1 part isocyanate by weight [8].…”