For decades, significant work has been conducted regarding plastic waste by dealing with rejected materials in waste masses through their accumulation, sorting and recycling. Important political and technical challenges are involved, especially with respect to landfilled waste. Plastic is popular and, notwithstanding decrease policies, it will remain a material widely used in most economic sectors. However, questions of plastic waste recycling in the contemporary world cannot be solved without knowing the material, which can be achieved by careful sampling, analysis and quantification. Plastic is heterogeneous, but usually all plastic waste is jointly handled for recycling and incineration. Separation before processing waste through the analytical approach must be applied. Modern landfill mining and site clean-up projects in contemporary waste management systems require comprehensive material studies ranging from the macro-characterization of waste masses to a more detailed analysis of hazardous constituents and properties from an energy calorific standpoint—where, among other methods, thermogravimetric research coupled with life cycle assessment (LCA) and economic assessment is highly welcomed.

Biomass is defined as organic matter from living organisms represented in all kingdoms. It is recognized to be an excellent source of proteins, polysaccharides and lipids and, as such, embodies a tailored feedstock for new products and processes to apply in green industries. The industrial processes focused on the valorization of terrestrial biomass are well established, but marine sources still represent an untapped resource. Oceans and seas occupy over 70% of the Earth’s surface and are used intensively in worldwide economies through the fishery industry, as logistical routes, for mining ores and exploitation of fossil fuels, among others. All these activities produce waste. The other source of unused biomass derives from the beach wrack or washed-ashore organic material, especially in highly eutrophicated marine ecosystems. The development of high-added-value products from these side streams has been given priority in recent years due to the detection of a broad range of biopolymers, multiple nutrients and functional compounds that could find applications for human consumption or use in livestock/pet food, pharmaceutical and other industries. This review comprises a broad thematic approach in marine waste valorization, addressing the main achievements in marine biotechnology for advancing the circular economy, ranging from bioremediation applications for pollution treatment to energy and valorization for biomedical applications. It also includes a broad overview of the valorization of side streams in three selected case study areas: Norway, Scotland, and the Baltic Sea.

Industrial and strategic significance of platinum group elements (PGEs)—Os, Ir, Ru, Rh, Pd, Pt—makes them irreplaceable; furthermore, some PGEs are used by investors as “safe heaven” assets traded in the commodity markets. This review analyzes PGEs from various aspects: their place in the geosphere, destiny in the anthroposphere, and opportunity in the economy considering interactions among the exploration, recycling of urban ores, trade markets, speculative rhetoric, and changes required for successful technological progress towards the implementation of sustainability. The global market of PGEs is driven by several concerns: costs for extraction/recycling; logistics; the demand of industries; policies of waste management. Diversity of application and specific chemical properties, as well as improper waste management, make the recycling of PGEs complicated. The processing approach depends on composition and the amount of available waste material, and so therefore urban ores are a significant source of PGEs, especially when the supply of elements is limited by geopolitical or market tensions. Recycling potential of urban ores is particularly important in a long-term view disregarding short-term economic fluctuations, and it should influence investment flows in the advancement of innovation.

Implementation of construction works on weak (e.g., compressible, collapsible, expansive) soils such as peatlands often is limited by logistics of equipment and shortage of available and applicable materials. If preloading or floating roads on geogrid reinforcement or piled embankments cannot be implemented, then soil stabilization is needed. Sustainable soil stabilization in an environmentally friendly way is recommended instead of applying known conventional methods such as pure cementing or excavation and a single replacement of soils. Substitution of conventional material (cement) and primary raw material (lime) with secondary raw material (waste and byproducts from industries) corresponds to the Sustainable Development Goals set by the United Nations, preserves resources, saves energy, and reduces greenhouse gas emissions. Besides traditional material usage, soil stabilization is achievable through various secondary raw materials (listed according to their groups and subgroups): 1. thermally treated waste products: 1.1. ashes from agriculture production; 1.2. ashes from energy production; 1.3. ashes from various manufacturing; 1.4. ashes from waste processing; 1.5. high carbon content pyrolysis products; 2. untreated waste and new products made from secondary raw materials: 2.1. waste from municipal waste biological treatment and landfills; 2.2. waste from industries; 3. new products made from secondary raw materials: 3.1. composite materials. Efficient solutions in environmental engineering may eliminate excessive amounts of waste and support innovation in the circular economy for sustainable future.

Leaching of macronutrients such as nitrogen, phosphorus and potassium from soils is of particular interest in the Baltic Sea region because of its adverse effects on water quality. The objective of this study was to evaluate macronutrient leaching in a juvenile hybrid aspen (Populus tremula L. × P. tremuloides Michx.) plantation cultivated in an agroforestry system and fertilized with biogas production residues, wastewater sludge and wood ash in hemi-boreal climate conditions. Analysis of macronutrient concentrations in the soil solution showed that annual macronutrient leaching decreased over time after the establishment of the plantation and application of fertilizers. Moreover, macronutrient leaching was affected not only by meteorological conditions, but also by the type of fertilizer used. During the five years after establishment of the plantation, nitrate-nitrogen leaching decreased up to 99.6%, phosphate-phosphorus leaching decreased up to 97.1%, but potassium ions leaching decreased up to 76.5%. Nevertheless, juvenile hybrid aspen plantations cultivated in an agroforestry system remain an important part in mitigation of leaching of macronutrients from agricultural lands in the Baltic Sea region.

The urbanization and increasing growth of planet's population accumulates significant volume of disposed waste as well as increases risks on human health and environmental safety. Landfill systems are the dynamic, living in space and time, potentially harmful entities that must be managed in as careful and smart way as possible. There are many studies related to landfill emissions such as leachates and methane. However, there is a need for advanced understanding of landfill hydrological regime and risks related to climate change and associated changes of hydrological cycle. The comprehensive studies about the urban hydrology are available; however, application to landfill management is fragmentary and inconsistent in several aspects. Landfill in long term has an impact on hydrological cycle. The heterogeneous land surface is one of aspects; however, there are still unanswered questions about the urban environment impact on water balance components. The aim of this study is to describe fundamentals of landfill hydrology in urban hydrological response unit context as well as evaluate the potential risks to environment and human health related to landfill geomorphology and hydrological balance in temporal climate conditions. The landfill hydrological cycle has similarities with urban hydrological cycle; however, there are additional components related to landfill specification, e.g., irrigation or leachate recirculation as well as total produced leachate.

Management of remediation projects in contaminated sites has become an increasingly global challenge and nowadays takes intensive international environmentally sound cooperation intended to relieve negative consequences of landscape pollution. This paper aims to deal with the phytoremediation approach for protection of environment and preventing the streaming of contaminant flows to hydrological systems. Phytoremediation is a cost-effective environmentally friendly clean-up technology, which uses plants and microorganisms in rhizosphere for soil and groundwater treatment. Phytoremediation is enhancing degradation of organic pollutants and improving stabilization of inorganic contaminants where plants can be used to treat soil and water polluted with hydrocarbons, chlorinated substances, pesticides, metals, explosives, radionuclides as well as to reduce the excess of nutrients. Selection of species for this type of treatment processes is based on evapotranspiration potential and ability to bioaccumulate contaminants. The project entitled "Phytoremediation Park for treatment and recreation at glassworks contaminated sites" (PHYTECO) aimed at cross-sector international partnership. The challenge of project was to develop remediation strategy where negative consequences from centuries long anthropogenic influence are turned to be something positive -development of the recreation park from the glass dump. Here designers, scientists, local volunteers, international students would join ideas and common work for the boost of innovation and sustainable thinking. New "Knowledge in Inter Baltic Partnership Exchange for Future Regional Circular Economy Cooperation" (PECEC) project is sequential continuation.

Methane is considered to be the main greenhouse gas (GHG) emitted by livestock. One method for reducing methane emissions from ruminants is to improve production efficiency, which reduces methane emissions per unit of product (FAO, 2010; Gworgwor, Mbahi, & Yakubu, 2006). There are many researches about prebiotics which can reduce methane production in livestock, for example, galacto-oligosaccharides reduced methane emission up to 11% (liters/ day) (Zhou et al., 2004). There is almost no information about prebiotic inulin, so the aim of this research was to determine the impact of different dosages of inulin concentrate (50%) on the increase of calves' body weight and its impact on methane emission, as well as to find out how the results change if it is added to barley flour not to milk as in our previous research. Approximately fifty days old, clinically healthy, different Holstein Friesian crossbreed calves kept in groups of 8, in a partly closed space with a natural ventilation through windows were included in this research. Eight calves were in the control group (CoG) and sixteen received inulin (Pre12 (n = 8), Pre24 (n = 8)). At the beginning of the experiment-the 28 th and 56 th day-we determined each calf's weight and measured the methane level in the rumen by using the PICARROG-2508 gas analyser (Fleck, 2013). We concluded that inulin supplement significantly (p ≤ 0.05) increased the live weight gain comparing Pre24 and CoG. The highest methane production on 1 kg of body weight at the end of the research was detected in Pre24-1.24 mg m-3 and the lowest in CoG-0.99 mg m-3 .