Modelling transport of waste material leachate in soils in support of environmental standards 771402004

Modelling transport of waste material leachate in soils in support of environmental standards

[ Modellering van het transport van het percolaat uit een afvalstof in de bodem ter ondersteuning van milieuhygienische normen ]

van Eijkeren JCH, Aalbers TG, de Wilde PGM

34 p in English 1992

RIVM Rapport 771402004

Toon Nederlands

English Abstract
In the Netherlands a process of defining environmental standards is going on. These standards serve to protect the environment at the one hand, and to stimulate the reuse of rest-materials, e.g. ash from blast-furnaces, as building materials at the other hand. In order to come to an environmental legislation, quality-goals have been established for soil and (ground)water. Trustworthy and widely accepted testing methods are necessary to control the standards and to verify the quality-goals. Experimental verification has to be supported by theoretical modelling of physical and (bio-) chemical processes. Moreover, mathematical models are powerful tools for the prediction of the effect of the standards at the long range, when the duration or costs of experimental verification can be prohibitive. Therefore, a computer model that simulates the burden on an underlying soil of a reused waste-material has been developed. The model simulates coupled transport and behaviour of a set of chemical components. These components are assumed to be in mutual chemical equilibrium. Transport is assumed to occur by advection and dispersion. Equilibrium speciation of the components in aqueous solution is modelled by minimization of the chemical potential. The model code name is TRAMIN, from TRAnsport and MINeql. The MINEQL code, been attached to the transport module, MINimizes the chemical potential of a set of components in EQuiLibrium. The model has been used to simulate a laboratory experiment. From this application it appears that the existing data base should be extended with respect to complexation and precipitation and with respect to soil dependent sorption. Lack of a description for surface layer sorption prevented the modelling of iron-oxide, which was also a constituent of the percolate and the soil matrix. Further developments are continued, in close cooperation with the Agricultural University of Wageningen.

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