Biofilm processes are now known to play hugely important roles in water treatment and the water environment: there is a rapidly expanding body of research leading to better understanding of biofilm processes in biofilm reactors and natural systems, biofouling and biocorrosion. This issue of Water Science and Technology is developed from work originally presented at the Biofilm Systems VI conference, at which over 225 delegates examined the state of the art in biofilm systems research. The contributions ranged from applied to basic research, and covered wastewater and drinking water applications. Following a full peer review 62 papers were selected for this issue. Several trends were observed: the use of genomic tools as enabling more in-depth studies of the microbial ecology of biofilms; developing computational methods for modelling biofilm processes leasding to better understanding of biofilm systems; aerobic granular sludge as a rapidly emerging new reactor technology (featured in a state-of-the-art paper); and biofouling in membrane systems for water treatment.
More traditional biofilm systems such as biological aerated filters remain important with evaluations of how these technologies are fulfilling the promises originally offered.