For safe water reuse, pathogenic viruses need to be efficiently controlled. Membrane filtration is considered to be an effective technology for virus removal. The present work explores mechanisms of human adenovirus 2 (HAdV-2) removal by a hollow fiber microfiltration membrane (d(pore) =0.2 mu m) as a function of influent virus concentration ranging from 1.3 x 10(7) to 3.4 x 10(8) copies/mL. A gradual decrease of HAdV-2 removal over time was observed at the beginning of filtration and was attributed to the accumulation of rejected HAdV-2 at the membrane surface or within membrane pores. Flux decline analysis revealed that complete pore blocking and standard pore blocking dominated the early stages of filtration and then transited to cake filtration at longer filtration time as the primary reason for flux decline. Deposition of HAdV-2 onto the membrane during the later stages of filtration led to the formation of a partly irreversible fouling layer and an increase of HAdV-2 removal. The understanding of HAdV-2 behavior at the membrane surface revealed in this study can help with the development of antifouling membranes with high virus removal efficiency. (C) 2015 Published by Elsevier B.V.