Climate impacts of source-separated biowaste from small neighbourhoods in Finland based on pilot experiments for novel biowaste collection systems.

The climate impacts of biowaste collection and utilisation were assessed based on data from two regional pilots. The EU's waste legislation will require biowaste source separation and collection from detached houses in communities with over 10,000 inhabitants starting from 2024 onwards. Two novel biowaste collection approaches were piloted in two Finnish case regions. One with biowaste collection to larger biolinks with a van and another with composting biowaste bins. The biolink approach reduces the need for waste truck driving, while composting biowaste bins enable an extended collection period. A life cycle assessment method was applied to assess the climate impacts of biowaste collection options and utilisation compared with current practices. The results show that source separation of biowaste and direction to biogas production leads to lower overall greenhouse gas (GHG) emissions at the system level compared with the current waste incineration option. Waste logistics has only a minor role in total GHG emissions, but a system based on biolinks and biowaste collection using a van led to the lowest GHG emission levels. Therefore, from a GHG emissions perspective, encouraging people to source separate their biowaste should be made as easy and encouraging as possible, no matter how the actual logistics is provided. However, novel and improved approaches for source-separated biowaste collection provide the potential for additional GHG emissions reductions.

Long-term evolution of the climate change impacts of solid household waste management in Lappeenranta, Finland.

Waste management processes have developed significantly in recent decades and will continue to change alongside the associated environmental impacts. This paper examines the climate change impacts of historical development in waste management, which has not received significant attention in the existing literature, while also exploring possible future developments. The city of Lappeenranta in Finland was selected as a case study, and the climate impacts of household waste (HW) management were calculated for the actual situations in 2009 and 2019 and the foreseen situation in 2029. Separately collected waste fractions of mixed residual waste (MRW), biowaste, cardboard, plastic, metal, and glass were included in the analysis. The results show that the net climate change impact decreased considerably from 945 kgCO2-eq./tHW in 2009 to -141 kgCO2-eq./tHW in 2019 mainly by directing the MRW to energy recovery instead of landfill. The emissions responsible for climate change could be further reduced in 2029 by directing biowaste to digestion instead of composting and by directing more fractions to recycling; e.g., plastic, the impact of which is affected by the demand for recycled plastic. For the year 2029, the net climate change impact was -181 kgCO2-eq./tHW when heat produced from MRW displaced natural gas and was as high as 142 kgCO2-eq./tHW if the heat substituted biomass heat. The findings reveal that as energy production mixes and materials become less fossil carbon intensive, they have a significant impact on the net climate impacts of waste management.

Method for residual household waste composition studies.

The rising awareness of decreasing natural resources has brought forward the idea of a circular economy and resource efficiency in Europe. As a part of this movement, European countries have identified the need to monitor residual waste flows in order to make recycling more efficient. In Finland, studies on the composition of residual household waste have mostly been conducted using different methods, which makes the comparison of the results difficult. The aim of this study was to develop a reliable method for residual household waste composition studies. First, a literature review on European study methods was performed. Also, 19 Finnish waste composition studies were compared in order to identify the shortcomings of the current Finnish residual household waste composition data. Moreover, the information needs of different waste management authorities concerning residual household waste were studied through a survey and personal interviews. Stratification, sampling, the classification of fractions and statistical analysis were identified as the key factors in a residual household waste composition study. The area studied should be divided into non-overlapping strata in order to decrease the heterogeneity of waste and enable comparisons between different waste producers. A minimum of six subsamples, each 100 kg, from each stratum should be sorted. Confidence intervals for each waste category should be determined in order to evaluate the applicability of the results. A new three-level classification system was created based on Finnish stakeholders' information needs and compared to four other European waste composition study classifications.