a b s t r a c tThis paper proposes an overarching review of national municipal waste management systems and wasteto-energy as an important part of it in the context of circular economy in the selected countries in Europe. The growth of population and rising standards of living means that the consumption of goods and energy is increasing. On the one hand, consumption leads to an increase in the generation of waste. On the other hand, the correlation between increased wealth and increased energy consumption is very strong as well. Given that the average heating value of municipal solid waste (MSW) is approximately 10 MJ/kg, it seems logical to use waste as a source of energy. Traditionally, waste-to-energy (WtE) has been associated with incineration. Yet, the term is much broader, embracing various waste treatment processes generating energy (for instance, in the form of electricity and/or heat or producing a wastederived fuel). Turning waste into energy can be one key to a circular economy enabling the value of products, materials, and resources to be maintained on the market for as long as possible, minimising waste and resource use. As the circular economy is at the top of the EU agenda, all Member States of the EU (including the EEA countries) should move away from the old-fashioned disposal of waste to a more intelligent waste treatment encompassing the circular economy approach in their waste policies. Therefore, the article examines how these EU policies are implemented in practice. Given that WtE traditionally is attached to the MSW management and organisation, the focus of this article is twofold. Firstly, it aims to identify the different practices of municipal waste management employed in selected countries and their approaches in embracing the circular economy and, secondly, the extent to which WtE technologies play any role in this context. The following countries, Estonia, Greece, Italy, Latvia, Lithuania, Norway, Poland, Slovenia, Spain, and the UK were chosen to depict a broad European context.

Since society at large became aware of the use of nanomaterials in ever growing quantities in consumer products and their presence in the environment, critical interest in the impact of this emerging technology has grown. The main concern is whether the unknown risks of engineered nanoparticles (NPs), in particular their impact on health and environment, outweighs their established benefits for society. Therefore, a key issue in this field is to evaluate their potential toxicity. In this context we evaluated the effects on plants and microorganisms of model nanoparticles, in particular of a stable metal (Au, 10nm mean diameter), a well-known bactericide (Ag, 2 nm mean diameter) and the broadly used Fe(3)O(4) (7 nm mean diameter). The toxicity of these nanoparticles was assayed using standard toxicity tests. Specifically, germination (cucumber and lettuce), bioluminescent (Photobacterium phosphoreum) and anaerobic toxicity tests were performed. Germination tests were conducted at a NP dose of 62, 100 and 116 microg mL(-1) for Au, Ag, and Fe(3)O(4), respectively. The bioluminscent testing (P. phosphoreum) was conducted at a dose of 28, 45 and 52 microg mL(-1) for Au, Ag, and Fe(3)O(4), respectively. Finally, anaerobic tests were conducted at a NP dose of 10, 16 and 18 microg mL(-1) for Au, Ag, and Fe(3)O(4), respectively. In all cases low or zero toxicity was observed. However, some perturbation of the normal functions with respect to controls in germinating tests was observed, suggesting the necessity for further research in this field. At the same time, the effect of NP-solvents was sometimes more significant than that of the NPs themselves, a point that is of special interest for future nanotoxicological studies.

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Environmental impacts and gaseous emissions associated to home and industrial composting of the source-separated organic fraction of municipal solid waste have been evaluated using the environmental tool of life cycle assessment (LCA). Experimental data of both scenarios were experimentally collected. The functional unit used was one ton of organic waste. Ammonia, methane and nitrous oxide released from home composting (HC) were more than five times higher than those of industrial composting (IC) but the latter involved within 2 and 53 times more consumption or generation of transport, energy, water, infrastructures, waste and Volatile Organic Compounds (VOCs) emissions than HC. Therefore, results indicated that IC was more impacting than HC for four of the impact categories considered (abiotic depletion, ozone layer depletion, photochemical oxidation and cumulative energy demand) and less impacting for the other three (acidification, eutrophication and global warming). Production of composting bin and gaseous emissions are the main responsible for the HC impacts, whereas for IC the main contributions come from collection and transportation of organic waste, electricity consumption, dumped waste and VOCs emission. These results suggest that HC may be an interesting alternative or complement to IC in low density areas of population.

21 22In this study, suspended cerium oxide nanoparticles stabilized with 23 hexamethylenetetramine were used for the removal of dissolved chromium VI in pure 24water. Several concentrations of adsorbent and adsorbate were tested, trying to cover a 25 large range of possible real conditions. Results showed that the Freundlich isotherm 26 represented well the adsorption equilibrium reached between nanoparticles and 27 chromium, whereas adsorption kinetics could be modeled by a pseudo-second order 28 expression. The separation of chromium-cerium nanoparticles from the medium and the 29 desorption of chromium using sodium hydroxide without cerium losses was obtained. P r e -p r i n t 3