The Alum Shales are black shale of Middle Cambrian to Tremadocian (Lower Ordovician) found predominantly in southern Scandinavia. The name originates from the presence of the alum-(K) mineral, which is a hydrated potassium sulphate.
Alum shales in the Oslo region, extending from Brevik to Hamar, are exposed over large areas of south-eastern Norway. When exposed to atmospheric precipitation and snowmelt, pyrite and other sulphide minerals in alum shales dissolve, leading to acid rock drainage.
Project objective
Incineration bottom ash (IBA) is the main residue from municipal solid waste incineration and refers to the incombustible materials that remain in the furnace after combustion. It is a very heterogeneous material, comprising irregularly shaped particles and diverse chemical compositions over a broad particle size distribution. This secondary waste may contain more than 30 wt.% amorphous silica, and major crystalline phases (> wt.1%) such as silicates, oxides and carbonates, which in turn, contain varying amounts of metals (Bayuseno and Schmahl, 2010).
In this MSc thesis, the effect of interlaying and mixing alum shales with IBA materials will be investigated to evaluate how its high pH contributes to neutralizing the acid rock drainage from alum shales.
In addition to IBA microstructural analysis (SEM and EDS) and quantification for grain size and (chemical/mineralogical) composition, the research primarily utilizes laboratory column experiments. Investigating fluid flow properties in the porous geometries between the mineral/glassy aggregates will contribute to assessing the level of fluid-surface interactions.
In addition to laboratory work, PHREEQC geochemical and contaminant transport modelling is foreseen as part of this master project.
Research questions
There are three overarching questions:
- How does the leaching behaviour of IBA position them as a neutralizing agent?
- How does mixing and interlayering of IBA with Alum Shale control the environmental impact of acid rock drainage?
- Are there any downside and adverse consequences of using IBA?
Additional information:
You will get training in experimental and numerical reactive transport (geochemistry) relevant to many environmental geoscience and hydrogeological studies, in addition to advanced material characterization with scanning electron microscopy and particle size/composition analysis. A good geochemistry and fluid flow background in porous media is recommended to undertake the project.
Reference:
Bayuseno, A.P. and Schmahl, W.W. (2010) Understanding the chemical and mineralogical properties of the inorganic portion of MSWI bottom ash. Waste Management 30: 1509–1520, https://doi.org/10.1016/j.wasman.2010.03.010