The use of volcanic soil as mineral landfill liner - I. Physicochemical characterization and comparison with zeolites

Abstract

The main physicochemical characteristics of the volcanic soil of Southern Chile, with allophane as the main pedogenic mineral phase were analysed and compared with common zeolites (clinoptilolite) of the European market. The ultimate goal of this study was to test volcanic soil for the use as mineral landfill liner. The main results indicated that the clay and silt fractions together of the volcanic soil were between 38 and 54%. The buffering capacity of the volcanic soil was higher compared with the studied zeolites, whereas the cationic exchange capacity of the volcanic soil (between 5.2 and 6.5 cmol + kg(-1)) is of the same order of magnitude of the studied zeolites (between 9.7 and 11.4 cmol + kg(-1)). Moreover, the anionic exchange capacity of the volcanic soil was higher compared to the zeolites analysed. The hydraulic conductivity of the volcanic soil, measured in the laboratory at maximum proctor density, ranges between 5.16 x 10(-9) and 6.48 x 10(-9) m s(-1), a range that is comparable to the value of 4.51 x 10(-9) m s(-1) of the studied zeolite. The Proctor densities of the volcanic soil are in a lower range (between 1.11 and 1.15 g ml(-1)) compared with zeolites (between 1.19 and 1.34 g ml(-1)). The volcanic soil physicochemical characteristics are comparable to all the requirements established in the Austrian landfill directive (DVO, 2000). Therefore, the use as mineral landfill basal sealing of the analysed volcanic soil appears reasonable, having a pollutant adsorption capacity comparable to zeolites. It is of special interest for Southern Chile, because there are no alternative mineral raw materials for basal liners of landfills.

Hydraulic conductivity of compacted zeolites

“…Thus, only hydraulic conductivities of zeolites compacted at optimum water contents are considered in Figure 6. The data from Navia et al (2005) corresponds well with the findings of this study. Then, hydraulic conductivity slightly increased beyond 39% fine content.…”

Clay barriers for protecting historic buildings from ground moisture intrusion

“…The till is quite different to some other naturally occurring clay barrier materials with similarly low measured hydraulic conductivities [12,13]. The volcanic Chilean soil and the clastic Turkish clay examined in these studies display marked differences themselves, although the presence swelling clays and calcareous minerals was noted in both.…”

“…Use of clay barriers has also become widespread in sealing landfill and waste repositories. Whilst specialised bentonite-sand mixtures or geotextiles are commonly selected, naturally occurring soils have been tested for suitability and used as alternatives [12,13].…”

A Batch Study on Removal of Heavy Metals Using Laterite Soil-Pressmud in Landfill Leachate

“…Soil cover serves as hydraulic barriers [4]. Soil cover with low permeability can reduce the filtration of leachate through waste thus minimizing the migration of toxic pollutants, including heavy metals [5]. It also has been studied that municipal solid waste biostabilization was related to intermediate soil cover characteristics that controlled the decomposition rate of waste [6].…”