It is generally believed that bio-waste is a suitable substrate for valorizations through fermentation with biogas production. An increasing number of municipalities in Poland implement selective collection of bio-waste. Limited qualitative and quantitative data are available on the composition of household bio-waste, including the contaminant content. This paper presents the adopted research method and the analysis results of the composition of household bio-waste segregated at source from 4 rural and 4 urban communes, from districts with single-family and multi-family housing. Household bio-waste is mostly food waste (43.9 to 56.0%), with a smaller percentage of garden waste (27.4 to 46.3%). According to data from other countries, in Poland, ‘fruit and vegetable’ waste constitutes the main part of household bio-waste (from 40.0 to 53.8%). The share of “contaminants” is relatively high. The most contaminated waste is that collected in containers in city districts with multi-family housing (16.6%). The share of contaminants in bio-waste collected in bags (rural areas and cities with single-family housing exceeded 10.0%).

There is a general consensus that bio-waste is a suitable material for valorization by means of the fermentation process with the production of biogas. The success of a bio-waste closed-loop economy will ultimately be determined by the demand for the products made from it. Poor-quality composts and fermentation products will not be allowed on the market in the long term. This means that not only final products but also bio-waste from separate collections must also meet the quality requirements. The aim of this 12-month study was a monthly analysis determining the level of contaminants in bio-waste collected from rural communities, single-family neighborhoods in urban areas, and multi-family neighborhoods in urban areas. The share of contaminants in bio-waste from rural areas and single-family urban housing averaged 8.2% and 7.2%, respectively, while multi-family urban housing had a significantly higher average of 16.6%. The primary contaminants identified were treated wood, plastics, mineral wastes, paper, and glass in rural areas and plastics, paper, treated wood, glass, and textiles in urban areas. The close positive correlation found between the total content of pollutants and, in particular, with plastics and kitchen waste in bio-waste collected in rural communities and from multi-family housing in cities indicates that they are likely the main source of the origin of these pollutants.

The growing volume of household waste, especially bio-waste, poses a significant challenge to waste management systems. In Poland, bio-waste accounts for almost one third of total waste generation. To address this challenge, in the context of optimising the waste biomass value chain, we are investigating the potential of methane fermentation to convert bio-waste into valuable end products in the form of digestate (organic recycling) and biogas (a renewable energy source with a wide range of downstream applications). This paper presents the moisture content, loss on ignition and biogas and methane production efficiency for bio-waste and for the seven types of waste that are the main constituents of selectively collected bio-waste (meat, other edible waste (dairy), fruits and vegetables, grass, leaves, branches and the < 10 mm fraction). Data on the technological properties of bio-waste and its constituents may be of interest to a range of stakeholders. The average moisture content ranged from 41.9% (<10 mm fraction and others) to 84.4% (fruits and vegetables), and the average organic matter content of the dry weight of the waste ranged from 37.8% (<10 mm fraction and others) to 88.7% (edible constituents other than meat and fruits and vegetables). The bio-waste had an average moisture content of 71.3 ± 1.7% and loss on ignition of 68.6 ± 1.7%. Biogas production from selectively collected bio-waste ranged from 285 to 404 Ndm³∙kg⁻¹ DM (mean: 347 ± 53 Ndm³∙kg⁻¹ DM), and methane production ranged from 191 to 271 Ndm³∙kg⁻¹ DM (mean: 215 ± 33 Ndm³∙kg⁻¹ DM).

Waste delivered to the Marszów Plant was tested in order to research the effect of seasonal fluctuations on the quantity and composition of generated municipal waste and on the quantity and composition of selectively collected waste. Waste samples were collected once a month from November 2019 to October 2020. The results of the analysis showed that the quantity and composition of municipal waste generated during a week are different in terms of the subsequent months of the year. The quantity of generated municipal waste per capita per week ranges from 5.75 to 7.41 kg (cap·wk)⁻¹, on average 6.68 kg (cap·wk)⁻¹. The maximum values of the weekly indicators for generating the main material components of waste per capita were higher than the minimum by several up to more than 10 times (textiles). The total quantity of selectively collected paper, glass and plastics increased significantly during the conducted research at a rate of approx. 5% per month. The level of recovery concerning this waste over the period between November 2019 and February 2020 averaged at 29.1%, and between April and October 2020 it was nearly 10% higher (39.0%). The material composition of selectively collected waste in subsequent measurement series often differed. It is difficult to link the observed changes concerning the quantity and composition of the analysed waste streams with the seasons of the year, although weather conditions undoubtedly impact the consumption and functioning models of people, thus impacting the size of waste streams.

Separate collection and treatment systems for municipal solid waste (MSW) are designed to support efforts in sustainability. Biowaste accounts for the majority of MSW; thus, its proper management is essential. This study analyzes the impact of the presence of composting or anaerobic digestion (AD) facilities on MSW management. The management systems in Poland with composting and AD facilities were compared. Five fractions, including mixed/residual waste and biowaste, were collected in the analyzed regions; however, the rules for sorting biowaste varied. A drop in the collected residual/mixed MSW was noticed (by 3.8% to 6.6% year-on-year), while the biowaste stream increased, resulting in a 4–10% increase in the share of biowaste. The proportion of the organic fraction in biowaste was found to be 85–88%, but the proportion of food waste was slightly higher in the region with an AD facility (by about 3%). Plastics were the primary contaminants, accounting for approximately 5.5%. The presence of AD facilities has a positive impact on MSW management, including higher biowaste collection levels (67.5 kg per person versus 48.1 kg per person). Furthermore, under comparable regional conditions, economic gains were observed, such as relatively lower gate fees for biowaste (about 57 EUR per ton versus about 62 EUR per ton) and greater differences in fees between biowaste and residual/mixed MSW (about 80 EUR per ton versus about 14 EUR per ton).