Summary of Mathematical Models Capturing the Effect of Clogging in Permeable Reactive Barriers for Treating Acidic Groundwater

Acid sulphate soils are commonly found around the coastal regions of Australia. When exposed to air during excavation, floodwater drainage or construction processes, pyrite in these soils becomes oxidised forming sulphuric acid leading to contamination of groundwater and causing acid drainage in underground coal mines. To treat acidic groundwater, permeable reactive barriers (PRBs) or subsurface treatment zone filled with alkaline materials are introduced as a filter to remove contaminants and neutralise acidity caused by pyrite oxidation. However, accumulation of chemical precipitates and bacterial growth can reduce the porosity of PRBs which in turn reduces their longevity and functionality. In this paper, we discuss modelling clogging in PRBs which is due to the accumulation of bacteria and reactive aggregates becoming coated with chemical precipitates, and the effect of the clogging on the porosity of PRBs over time.