This paper elaborates a biogas plant for the treatment of biodegradable waste for the area of Istria County at a conceptual level. The first part of the paper describes the waste disposal issue, both in the European Union and in Croatia. The emphasis is put on the disproportion between waste production versus its recovery; excessive amounts of waste are disposed of in landfills instead of being separated at the place of origin or subsequently, to obtain a pure fraction, which is ready for further processing and obtaining higher value products such as compost or biomethane. The central part of the paper describes the technology of biomethane production from biodegradable waste in the process of anaerobic digestion. Components of the plant are listed with an approximate sizing of the main elements in regard to the amount of waste produced in the observed area and the results of laboratory tests of raw materials. The paper concludes with an economic cost-effectiveness analysis and an analysis of the biogas plant's advantages for the municipal waste management sector as a whole. The main, but at first invisible, benefit of waste recovery by a biogas plant is the circulation of carbon in a way that does not disturb the natural balance of greenhouse gases in the atmosphere. In other words, the circular economy of biodegradable waste contributes to climate neutrality and halting negative climate change.