A comprehensive study on numerical analysis of contaminant migration process in compacted clay liner and underlying aquifer for MSW landfill

Abstract

For the study of MSW landfills in which the lining system is composed of a compacted clay liner (CCL), a two-layer strata model is presented to reproduce the system which consists of a CCL and an underlying aquifer. Considering all types of mechanisms including advection, hydrodynamic dispersion and sorption of soil skeleton, one-dimensional differential equation is formulated for describing the migration behaviour of contaminant in the CCL and aquifer. Together with the actual initial and boundary conditions, the resulting initial boundary value issue is numerically solved by various effective procedures. Based on abundant numerical computations by varying various relevant parameters, the effects of the production modes of contaminant source, hydraulic conductivity and dispersion as well as various sorption behaviours of the CCL, the equilibrium and linear sorption of the aquifer as well as biochemical degradation on the migration behaviour of contaminants in both the CCL and aquifer are systematically examined. It is shown that an independent mechanism in addition to hydrodynamic dispersion and advection, the sorption of soil skeleton plays a much important role in controlling the migration behaviour of contaminants. The sorption model and its parameters should be carefully chosen in the numerical analysis of contaminants migration and design of MSW landfill. Moreover, both coefficients of hydraulic conductivity and dispersion of the CCL should be duly determined according to the actual condition. Compared with the sorption effect of the CCL, the influence of sorption of aquifer on the migration behaviour of contaminants can be overlooked.

Speciation of Heavy Metals in the Homogeneous Sandy Aquifer Affected by Landfill Leachate

“…This is due to the immobile metal complexes found in leachate-polluted groundwater. This is one of the most important aspects that is also reiterated in other studies [4,16,24].…”

“…The impact of landfills on the environment depends on their geological and hydrogeological conditions, composition of deposits, environmental morphology and technology of the particular landfill site design [8,16,24]. The pollution caused by leachate from a landfill depends on the composition of waste, the operation time of the landfill, its design and climatic conditions.…”

An analytical model for chemical diffusion in layered contaminated sediment systems with bioreactive caps

“…The value of A 1,i is arbitrary and is set to A 1,i = 1. Equations (24d) and (25) are used to find a symbolic general transcendental equation.…”

The influence of landfills located in different hydrogeological systems on Lithuanian groundwater quality

“…According inventory data of various countries in Europe there are about 150000 to 500000 non-operational and still operating municipal waste landfills with an average size of about 8000 m 2 and with a capacity of 30-50 billion m 3 of waste (Wagner, Raymond 2015; Jones et al 2013;Krook et al 2012). Although modern landfill technology has been used in the European Union and the United States since 1980, the number of old non-operational landfills without a leachate collection system comprises a large percentage of the above-mentioned landfills (Zhang et al 2015).…”

“…The landfill age and the physicochemical processes taking place inside the waste create a complex composition of leachate consisting of four pollutant groups: 1) dissolved organic matter; 2) inorganic macrocomponents; 3) heavy metals; 4) petroleum hydrocarbons (Bjerg et al 2011;Christensen et al 2001;Zhang et al 2015, Kjeldsen et al 2002Longe, Enekwechi 2007;Barella et al 2013). These four groups of pollutants are associated with research into groundwater circulation and its selfcleaning processes.…”