This work is focused on assessing the suitability of selected methods of processing the biological component of municipal waste and selected industrial waste. We evaluated organic waste using biodegradability tests. The intrinsic biodegradability test (Zahn-Wellens method) according to OECD 302 B, the biodegradability test in closed bottles according to OECD 301 D and the anaerobic biodegradability test of organic compounds in fermented sludge by measuring gas production according to OECD 311 were used. Basic physico-chemical analysis. We determined: pH value, dry matter content, loss on ignition, chemical oxygen demand and biological oxygen demand. In addition to input analyses and tests for the assessment of biodegradability, experiments were performed to optimize the conditions of anaerobic decomposition using the addition of ash from the municipal waste incinerator and ash from biomass combustion. The work also evaluated the biodegradability of rubber from waste tires. We evaluated the biodegradability by calculating the biodegradable fraction and the specific rate of degradation. These calculations were supplemented by an evaluation of biogas production. The significance of the differences in the obtained results of biogas production with respect to the type of pre-treatment was evaluated by statistical analysis ANOVA. The highest average degradation under aerobic conditions was observed with the decomposition of corn silage – 30.59 %. The highest average degradation in anaerobic conditions was found in the decomposition of waste whey and wastewater from cheese production - 85.93 %, respectively. 84.24 %. Due to the pre-treatment with ash from the incineration of municipal waste, the highest value of BR was found in the decomposition of combined wastewater from the dairy plant with the addition of 2.7 g/gdry matter at the level of 97 %. The highest value of q with respect to pre-treatment with ash from the incineration of municipal waste was observed in the decomposition of wastewater from the production of steamed cheese with the addition of ash 2.7 g/gdry matter at the level of 29 mg/(g · h). Due to pre-treatment with ash from municipal waste incineration, the highest average biogas production was observed during the decomposition of wastewater from cheese production with the addition of ash 2.7 g/gdry matter at the level of 390 m3/tloss on ignition. With regard to the effect of ash pretreatment from municipal waste incineration, optimal pH conditions were observed during the decomposition of wastewater from cheese production with the addition of 1.8 g/gdry matter ash.