Contaminant transport through peats: Soil behavior and risk assessment

Sriraam, A.S., and Raghunandan, M.E. (2014)., Proceedings of the 7th International Congress on Environmental Geotechnics (7ICEG), Melbourne, Australia, 589-596. ISBN: 9781922107237., 2014

Peats are well recognized as problematic soils, thus mandating significant improvements to the current state-of-the-art in construction industries and practices with due focus on the infrastructure and agricultural developments. Hence a thorough understanding on their behaviour and risks associated with various engineering activities forms a prime step towards sustainable environment. Contaminant transport through peats is one such risk that influences the environmental health of the soil itself. This further enhances the expectation towards higher values of permeability coefficient (k) due to high void ratio. Higher k values will certainly contribute towards the rate of contaminant flow through peats above ground water table. However, contaminants also experience advection and dispersion in high ground water conditions as commonly observed in wetlands from the South-east Asian region. This paper aims to address some of these issues by providing a detailed understanding of the factors affecting contaminant transport through peats using numerical models based on the concepts of advection and dispersion. The numerical approach presented by Zhao et al. (1994) was used to estimate the factors influencing the contaminant transport phenomenon, with the properties of peats as an input to represent the porous medium. The results and discussions of the parametric study highlight the influence of various properties of peats and the contaminant on permeability and concentration (contaminant) variation with time and depth. The findings show the role of dispersion coefficient (Dx) to be a prime driving force in determining the time for contaminant flow with depth.

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