The application of nanomaterials for water treatment and pollutant detection has been a topic of research for many years, with interesting applicative results at lab scale. In order to propose a scale-up and exploitation for these emerging technologies, the reactor configuration should be selected according to different criteria. One option is to scale up the slurry-type reactors employed on bench scale. Some forming of the nanomaterials is needed to allow suspension and recovery of the material. However, this configuration hardly fits the needs of large-scale treatment and of continuous operation. Structured materials can be better options in this regard, achievable by deposing the nanoparticles over preformed solid supports of various shape depending on the application. The main features of fixed-bed, slurry, and structured reactors are reviewed, with the main sizing and modeling issues. Finally, different techniques for the immobilization of nanomaterials over preformed solid targets are described, with some application to materials for water treatment and sensing. © 2020 Elsevier Inc. All rights reserved.