Reducing the environmental impact of human activities
Current Research Programmes
Emission Reduction of Landfills: STW funded project (2011-2015) with 2 PhD students and 1 post-doc and 1 PhD student funded by an Erasmus Mundus Exchange programme with India (EurIndia). Within this program we develop an in-depth understanding of the hydrological and biogeochemical processes in full-scale landfills, in order to quantify the (remaining) emission potential of a waste body. This programme has led to a stochastic framework for quantifying the emission potential using simply obtainable data such as rainfall, potential evaporation, cumulative leachate discharge and leachate quality. The framework is an integration of models quantifying (multi-phase) preferential flow through the (unsaturated) waste body, bio-geochemical kinetics within the waste body and subsequent development of leachate quality. Probability density functions obtained with this framework can be verified using a high resolution quantitative geophysical assessment of landfill heterogeneity. The results are also very valuable for optimizing landfill treatment methods such as irrigation/recirculation, to stimulate anaerobic degradation processes and landfill aeration in order to stimulate aerobic aeration processes. We have shown the potential for using shallow depth seismics to map the heterogeneity of waste bodies. The major innovation in this study is the use of seismic interferometry (SI) to enhance the signals. Using SI opens up the opportunity to do a physical interpretation of the seismic images obtained.
Impact of large infrastructural projects on archaeological sites: The aim of this program is to develop insights which lead to improved ways of preserving and exploiting archaeological resources in the subsurface, a topic that is a new challenge for Dutch geo-engineers. The aim is to investigate the impact of changing environments on buried archaeology in wetlands. Wetland environments provide perfect acidic anaerobic conditions to conserve archaeological remains below the ground water table as long as their multi-physics equilibrium is not disturbed by human activities. Wetland archaeological sites are used as large-scale laboratories for research on ageing of structures and materials and mitigation of degradation. The research involves computer and laboratory simulations of archaeological artefacts embedded in soils.
Past Research Programmes
Projects aimed at reducing the natural arsenic contamination of groundwater were carried out with partners from the University of Dhaka (Bangladesh), the Department of Technology Development and Sustainable Development (TU Delft), and the University of Patna (India). The EU Erasmus Mundus programme (EurIndia) supported 2 PhD students. The main research result is that the deep water (Pleistocene aquifers) was initially essentially arsenic free, but that large-scale water extraction withdraws contaminated water from shallower depth.
Research into CO2 -sequestration in coal layers, aquifers and shale led to 6 PhD theses. The work was largely experimental. A spin-off of this research was a comprehensive experimental error evaluation that went beyond the traditional random/systematic error approach. In addition, a fundamental study was carried out on enhanced mass transfer from carbon dioxide to the underlying brine layer. In addition were able to visualise, for the first time, natural convection flows in brine-CO2 systems.
Development of generic Exergy analysis of energy conversion processes in order to identify bottlenecks and how to improve the efficiency of a particular process.
Work on enhanced oil recovery methods that can be used for environmental applications was carried out on combustion, upscaling using homogenization, and solvent enhanced gravity drainage.
We have developed a high-resolution high-speed laboratory Electricity Resistivity Method in order to monitor in-situ mixing of injected reactants in groundwater.