The production of nanomaterials (NMs) such as SiO2, TiO2, ZnO, CeO2, and Al2O3 has increased in the last years because they are frequently incorporated in daily life products including sunscreen, cosmetics, and deodorants, among others. The NMs life cycle includes the analysis of how they may enter the environment and cause adverse effects. From this point of view, NMs can be viewed as nanopollutans. This review presents a summary of the most relevant information on NMs production, their transport on the environment, incidence in residual effluents and their effect on aerobic bioreactors for wastewater treatment. As shown in the present analysis, the presence of nanopollutans in aerobic bioreactors has negative effects in the removal of organic matter, nitrogen and phosphorous. This occurs mainly because of the internalization of nanopollutans in microorganisms, the gravitational settling, agglomeration and partial dissolution of nanopollutans. These processes indicated that the main output of nanopollutants from aerobic bioreactors is the sludge disposal.