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Circular economy offers opportunities to boost jobs and tackle climate change. The article reflects aspects of the impact on the environment through sectoral policies to support the circular economy because current business as usual model, based on the linear economy principle leads to a staggering inefficiency in nature resources are managed, with increased pollution, loss of ecosystems and substantial losses of value with each product disposed. This requires a change not only in consumer behaviour but even more on the resource extraction and material production side. The purpose of the research paper is to develop a decision-making matrix providing a step-by-step approach for the policymakers.

Promocijas darba pētījuma objekts ir atkritumi kā efektīvs resurss ceļā uz aprites ekonomikas modeli. Saskaņā ar Aprites ekonomikas pakotni ES dalībvalstīm noteikti kvalitatīvi un kvantitatīvi mērķi atkritumu apsaimniekošanā, tajā skaitā atkritumu apjoma samazināšana un pārdomāta apsaimniekošana. Izvirzītā hipotēze ietver pieņēmumu, ka, lai panāktu, ka Latvija ilgtermiņā kļūst par resursu efektīvu valsti, kas īsteno aprites ekonomikas modeli un nulles atkritumu stratēģiju, ilgtspējīgāku rezultātu var sasniegt, lēmumu pieņemšanā izmantojot zinātniskās pētniecības metodes. Promocijas darbs balstīts desmit tematiski saistītās zinātniskās publikācijās, kas ir publicētas zinātniskajos žurnālos un pieejamas zinātnisko publikāciju datubāzēs.

The research subject of the Doctoral Thesis is waste as an efficient resource on the way to a circular economy model. According to the Circular Economy Package, EU member states have set qualitative and quantitative goals in the waste management, including waste volume reduction and thoughtful management. The hypothesis put forward for the study includes the assumption that for Latvia to become a resource-efficient country in the long term and to implement a circular economy model and a zero waste strategy, a more sustainable result needs to be achieved and scientific research methods need to be applied throughout the decision-making process. The Thesis is based on ten, thematically related scientific publications, which have been published in scientific journals and are available in databases of scientific publications.

The paper examines the role and place of green enterprises, green jobs and the environmentally sound activities of society in waste management, taking into account the waste management hierarchy with an emphasis on waste reduction and prevention. In the course of the work, a questionnaire was prepared on the role green enterprises, green jobs and the environmentally friendly activities of society play in the development of a waste management system. The TOPSIS method of multi-criteria analysis was used to assess these roles in the development of a circular economy, including in relation to a waste management system. Through the assessment of the roles of these green measures in the field of waste management, the results clearly show that the most effective of the selected alternatives in the circular economy model in the field of separate collection and recycling of waste can be achieved via measure exercised by green enterprises, followed by green jobs and finally – the role of environmentally sound activities taken by the public, which play an important role as well.

Paper waste is a raw material for a lot of products with different added value. The engineering, economic and environmental aspects of paper waste recycling are analysed for production of composite material, cellulose nanofibers and nanocrystals, bricks with paper components, porous carbon, film of biopolymer, enzymatic sugar and bioenergy: bioethanol, hydrogen and biofuel. Through multicriteria analysis, it was possible to determine the most feasible paper waste recycling product in case of four product groups: egg packaging boxes, cardboard, reused paper, cellulose nanomaterials (nanofibers and nanocrystals). The production of cellulose nanofibres and cellulose nanocrystals has an advantage over egg packaging and cardboard production as well as reusable paper.

Waste management system is a complex system involving numerous waste streams, collection schemes, treatment processes and various actors. Bus as well as many other systems, waste management is recently experiencing new and more sustainable development trends including the promotion of circular economy and increased material recycling. Hence there is a need for the implementation of an improved waste management system that requires a significant and thorough planning stage, the results of which will significantly depend on the availability of detailed information of the possible waste flows and waste composition. The aim of this paper is to experimentally determine and analyse the composition of unsorted municipal waste to provide assessment for incorporating waste composition analysis into further planning and modelling of a next generation waste management system in Latvia. The experimental results indicate that the unsorted municipal waste stream comprises of up to 32.9 % of recyclable materials and 29.2 % of biodegradable wastes. Thus almost 60 % of the waste currently being subjected to unsorted waste management system in Latvia could potentially be source separated ensuring higher quality of the recovered materials and promoting circular value chains. The results indicate a slight difference between waste composition in different waste management regions, thus noting that, in addition to the number of inhabitants and their habits, the local system in each waste management region may influence the composition of the collected wastes.

The aim of the circular economy is to maximize the value of a product during its use, using secondary raw materials to create new products. This research focus on the possibilities of using waste as an energy resource - both the aspects of waste recovery, from the point of view of reducing the amount of landfilled waste, and the extraction and further efficient use of landfill gas. In this case the TOPSIS analysis method was used, five alternatives were selected - waste as an energy resource, which was evaluated based on four criteria: technological, economic, social, as well as environmental and climate aspects. The results of ranking energy recovery methods from waste using the TOPSIS method clearly show that the most optimal of the selected alternatives is the use of biodegradable (organic) waste for biogas production. This opens up opportunities for biofuels to be applied in road transport.

According to the Latvian policy planning documents, the main macro indicators for monitoring progress of national development are: GDP per capita, income inequity index S80/S20 and national population growth. Policy planning documents propose different sectoral targets that are not linked with each other, sometimes providing conflicting goals. There are international and European Union (EU) targets (especially in the environmental and climate sector) that sometimes contradict with national goals and occasionally are not set as national priorities in Latvia and for which the necessary resources are not appropriated. The authors propose an improved methodological approach interlinking national policy indicators and sectoral models to generate more efficient decision making mechanisms.