Over one-third of the produced food is wasted globally. Most food is wasted at the consumer stage. The use of waste sorting analysis is considered to deliver more precise and less biased results than self-reporting methodologies. Currently, no detailed studies on the amounts and composition of household food waste are available for Poland. In the current paper the results of a food waste generation study in the city of Opole in Poland are presented. Both the residual and biowaste from 1425 citizens living in three different city areas was analysed during five seasonal waste sorting campaigns. The food waste was sorted in 16 avoidable and four non-avoidable fractions. The results of this study showed that in the city of Opole the absolute amount of both the avoidable and non-avoidable food waste is higher in the mixed waste stream than in the biowaste (42.8 kg inh.⁻¹ in the residual waste and 19 kg inh.⁻¹ in the biowaste, yearly). Thus, the total segregation level of food waste constitutes at the moment only 31%. The four main categories of avoidable food waste in the mixed waste are: bread (23.9%), vegetables (23.3%), meat (15.1%) and potatoes (7.8%). For the biowaste, the main four categories include: fruits (35.5%), other vegetables (27.9%), meal leftovers (13.6%) and bread (8.6%). Thus the overall food waste generation is 61.7 kg inh.⁻¹ year⁻¹. When also considering alternative discarding routes (sewerage, fed to animals or home-composted), the total food wastage in Opole amounts to 79.9 kg inh.⁻¹ year⁻¹, out of which 37.1 kg inh.⁻¹ year⁻¹ is avoidable waste and 42.8 kg inh.⁻¹ year⁻¹ non-avoidable waste.

Current and future trends in the world population lead to the continuous growth of municipal waste volumes. Only in the EU-28 approx. 86 million tons of biowaste is produced yearly. On the other hand, the recent energy crisis calls for a fast transition towards more local and renewable energy sources. Most of this stream could be recycled through anaerobic digestion (AD) to produce energy and high-quality fertilizers. This paper presents a balance of dry anaerobic digestion of municipal biowaste based on three years of system monitoring in an industrial-scale AD plant. The results indicate that the average biogas production rate of 120 Nm³/ton of fresh waste can be achieved. Biogas utilization in combined heat and power (CHP) units leads to an overall positive energy balance at significantly reduced CO₂ emissions. The overall CO₂ emission reduction of 25.3–26.6% was achieved, considering that biogas utilization is environmentally neutral. Moreover, biowaste conversion allows digestate production to substitute mineral fertilizers in agriculture and other applications. It is beneficial for soil protection and a broader environmental perspective.