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Title:
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Prediction of the leaching behaviour of waste mixtures by chemical speciation modelling based on a limited set of key parameters
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Author(s):
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Published by:
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Publication date:
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ECN
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1-10-2005
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ECN report number:
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Document type:
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ECN-RX--05-164
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Conference Paper
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Number of pages:
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Full text:
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14
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Download PDF
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Presented at: Sardinia 2005, Tenth International waste management and landfill symposium, Sardinia, Italy, 3-7 oktober 2005.
Abstract:
In previous work on a predominantly inorganic
waste landfill, carried out in the framework of developing sustainable
landfill concepts, detailed information on the leaching behaviour of
the wastes submitted for landfilling was obtained. Chemical speciation
modelling of the eluate composition obtained from testing the waste
mix in a laboratory column leaching test (0.0005 m3) and of the leachates
obtained from the lysimeter (1.5 m3) and field scale studies (12,000
m3 pilot cell) on the same waste mix with ORCHESTRA embedded in the
database/expert system LeachXS, is showing a rather good agreement between
modelling results on major, minor and trace elements and actual measurement.
A limited set of input parameters consisting of element availabilities,
relevant parameters for sub-models on adsorption to iron oxides, clay,
particulate and dissolved organic matter and a selective set of minerals
provides a revealing partitioning between dissolved and particulate
phases. Apart from describing the release behaviour in the pH dependence-leaching
test adequately, this information is most relevant for assessing changes
in each of release controlling properties (element availabilities, amount
of sorptive surfaces and redox). This type of modelling allows prediction
of changes in leachate quality as a result of waste input as this may
cause a change in element availability and quantity of sorptive surfaces. A few of such possible changes
have been modelled. This type of modelling provides the potential
for development of more sophisticated acceptance criteria as well as
possibilities to assess the level of aftercare
measures needed at the time of landfill closure.
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