This work proposes the generation of a preliminary project based on the biological treatment process called the Tubular Biological Reactor (RBT), to treat the wastewater discharges that contaminate the Xochimilco canals. The main focus of the work is: through the use of the FEL methodology to generate a design for the installation of a small wastewater treatment plant and thus be able to establish a treatment train based on RBT technology and thus translate it into a diagram of process blocks, subsequently constructing the Process Flow Diagram (DFP) which includes the pre-treatment equipment and main treatments that make up the treatment train, a material balance was prepared that considers urban wastewater as effluent in the tributary of the plant, the systems analyzed in the mass balance are; pretreatment, the sludge produced by the biological reactor as well as its treatment, the aeration systems and the disinfection of the effluent. To comply with NOM- 003- SEMARNAT-1997. With the complete mass balance, the pipeline and instrumentation diagram (DTI) was built and a Layout diagram was made to locate the equipment, this methodology allowed to generate a design that can be applied at various points of the Xochimilco channels, mainly where sewage discharges occur. wastewater treatment; tubular biological reactor.