The synergy between particles and biofilms that drives drinking water discolouration processes in PVC pipes

Microscopy images of PVC pipe wall samples were collected from the pipe loops of the Drinking Water Distribution Laboratory (DWDL) at Queen's University during experiments designed to investigate the accumulation and mobilization of iron oxide particles and biofilms in drinking water systems. Images were captured at magnifications of 100× and 400× using an automated epifluorescence microscope (Nikon Ni-E) with water immersion objectives. Brightfield images were used to visualize iron oxide particles on the blue PVC pipe surface, while fluorescence images, obtained using the DNA-labeling dye SYTO9, were used to visualize biofilm components. Merged images (SYTO9 + BF) were created using image processing tools implemented with Python algorithms.