This paper deals with an approach for hybrid and coupled modeling of the design of fixed and suspended biomass reactors for organic matter removal from sanitary landfill leachates. Five bioreactors, comprising Rotating Biological Contactors, Trickling Filter, Upflow Anaerobic Sludge Blanket, Upflow Anaerobic Filter in Two Separated Stages (UAF-2SS) and Upflow Anaerobic Filter in Three Separated Stages (UAF-3SS) were evaluated by treating the organic matter contained in the leachates produced in two sanitary landfills. With respect to the hybrid and coupled models, the best performance in the approximation of the measured values in the Se/Si ratio to the predicted results of models were the equations for UAF-2SS and UAF-3SS reactors. Hybrid models were made up of a combination of mass conservation law and equations for estimating transformation process. Coupled models consisted of a combination of transport process models and transformation models based on the substrate utilization rate by the microorganisms.