Sewage sludge (SS) is a by-product of processes conducted during the treatment of wastewater. It can be used in many different ways. One of them is the use of SS in agriculture as an organic fertiliser, but the main criterion for such use is the heavy metals (HMs) content. Knowledge of the total content of HMs in SS does not translate into the danger it may pose. The toxicity of metals is largely dependent on their mobility. The mobility of SS from three different wastewater treatment plants (WWTP) of the Świętokrzyskie Voivodeship, which were characterised by an increased zinc content, was examined in this study. The aim of the study was to prove whether the high level of zinc in SS actually disqualifies the possibility of its natural use. Calculations were made for five environmental hazard indicators: the geoaccumulation index of heavy metals in soil (I_geo), potential environmental risk indicator (PERI), risk assessment code (RAC), environmental risk factor (ERF), and the authors’ own environmental risk determinant (ERD) indicator. The obtained results show how important mobility analysis is when assessing the possibility of natural use of SS.

Climate and energy policies are the key areas of the European Union’s development aspirations in the international arena. The European Green Deal sets ambitious new goals in this respect, emphasizing clean energy. The development of the energy sector, relying chiefly on renewable sources, is one of the conditions for the EU to transition to energies that do not produce waste that pollutes or is otherwise harmful to the Earth and human health. This paper assesses the development of renewable sources of energy in the EU and identifies challenges to the realization of the EU’s energy priorities. An analysis of renewable sources of energy in the EU in 2012 and 2020 is the prime method. The generation of primary energy from renewable sources, the share of energy from renewable sources in the final energy consumption, the structure of energy generation from renewable sources, and the share of energy from renewable sources in the energy used by the transport sector are discussed. Secondary data are employed, made available by Eurostat and Statistics Poland. To reach the objective of the study, Z. Hellwig’s taxonomic method is applied to assess the development of renewable energy sources (RES). Cluster analysis (Ward’s agglomerative clustering method) is additionally used for separation of objects and member states that are similar with regard to the phenomenon reviewed. Particular attention is paid to the challenges that societies and economies face in view of the assumptions of the EU’s new Green Deal, which envisages a balancing of CO₂ emissions and absorption. This analysis discovers varied progress on the development of RES in the member states, posing a threat to the European community’s aspirations.

Sewage sludge (SS) from wastewater treatment plants (WWTPs) has important soil-forming and fertilizing properties. However, it may not always be used for this purpose. One of the main reasons why SS cannot be used for natural purposes is its heavy metal (HM) content. SS from the wastewater treatment plant in Poland was subjected to an analysis of the potential anthropogenic hazard of HMs, especially in terms of their mobility and accumulation in soil. Calculations were made for the concentrations of HMs in SS from the analyzed wastewater treatment plants and in arable soil from measurement points in places of its potential use. The geoaccumulation index (GAI), potential environmental risk index (PERI), risk assessment code (RAC) and environmental risk determinant (ERD) were calculated. Then the values of the indicators were compared with the mobility of HMs, which was the highest risk of soil contamination. It was shown that a high level of potential risk and geoaccumulation indicators did not necessarily disqualify the use of SS, provided that HMs were in immovable fractions.

Popular incineration of sewage sludge results in the increase in heavy metals content in ash. The knowledge of the total content of heavy metals in sewage sludge ash does not demonstrate a potential hazard. The toxicity of heavy metals in great measure depends on the form of their occurrence. The prevailing norms do not require the ecological risk assessment of the environmental burden with heavy metals for the choice of the method of the utilization of sewage sludge ash. The paper presents the research results on the mobility of heavy metals in sewage sludge ash after its incineration. The geo-accumulation index (I_GAI), the potential ecological risk index (PERI) and the risk assessment code (RAC) were used for the evaluation of the potential soil contamination with heavy metals. The authors also suggested a new formula, which took into consideration more factors influencing the risk of the contamination of a water-soil environment with heavy metals—the water and soil environment risk index (WSERI). The calculated indices for sewage sludge ash indicate the risk of soil contamination with heavy metals.

Spent coffee grounds (SCGs) are a waste product generated after brewing coffee. For every ton of brewed coffee, approximately 650 kg of grounds are produced. Their disposal can have harmful environmental effects, making it necessary to find alternative uses for SCGs. The valorization of coffee’s bioactive compounds significantly contributes to environmental protection and management. According to the literature, SCGs can be utilized as fertilizers, sorbents, additives for biodiesel production, in bioelectricity, or as an enhancer for the calorific value of biomass. SCGs can also be used as substrates for producing various items, such as cups or plant pots, in the food, cosmetics, and construction industries. The applications of SCGs described in this review article were conducted under laboratory conditions. The aim of this article is to analyze the alternative uses of SCGs in various fields, highlighting the diversity of applications as well as key drawbacks and limitations associated with their use. Additionally, potential future research directions are outlined, which could contribute to a more efficient and sustainable utilization of SCGs.

Steroid hormones are micropollutants that contaminate water worldwide and have significant impacts on human health and the environment, even at very low concentrations. The aim of this article is to provide an overview of technologies for the removal of endocrine-disrupting compounds with a focus on oestrogens (estrone E1, 17β-oestradiol E2, estriol E3), the synthetic oestrogen (17α-ethinylestradiol EE2 and bisphenol A BPA), and pharmaceuticals found in wastewater. Hormonal and pharmaceutical contaminants are mostly persistent organic compounds that cannot be easily removed using conventional wastewater treatment processes. For this reason, researchers have tried to develop more efficient tertiary wastewater treatment technologies to reduce micropollutant concentrations in wastewater. This review covers the following processes: Advanced oxidation, nanofiltration, ultrasound, electro-Fenton processes, electrolysis, adsorption, ozonation, photolysis, photocatalysis, ultrafiltration, and electrocoagulation. Attention was paid to the effectiveness of the processes in terms of eliminating hormones and pharmaceuticals from wastewater, as well as on economic and environmental aspects. The combination of different processes can be a promising treatment scheme for retaining and degrading hormonal and pharmaceutical compounds from wastewater. With hybrid technologies, the advantages of the methods are combined to maximise the removal of pollutants. However, optimal methods of wastewater treatment depend on the quality and quantity of the wastewater, as well as the residual hormonal and pharmaceutical compounds and their hazardous effects.