This paper discusses the economic model of construction and operation of biogas plant treating biodegradable municipal waste that has been developed for the real needs of the project in the Czech Republic. The model is designed as an universal for different sizes of catchment areas and biogas plants and it allows due to own setting of input values make an evaluation of the various solutions of the system. The prerequisite is integrated waste management system approach in the region with up to 100 000 inhabitants and BMW flow connected to the biogas plant amended by other facility (composting plant). The main component of the paper is a pair of economic models of functions of the integrated system and especially the construction and operation of biogas plants based on the technology of wet anaerobic digestion. Although the wet anaerobic digestion technology, which is in comparison with dry one technologically more sophisticated and safer, is usually also the more expensive method of handling BMW, the model shows that in the real economic conditions of the Czech Republic in the event of a successful application for grant support of the project can be achieved the payback period in the length of several years, depending mainly on the waste market prices, purchase of the energy from renewable sources and use the output digestate as a fertilizer.