The study aims to investigate the possibility of producing hydrogen from sewage sludge obtained during wastewater treatment, using emission factors. It provides an overview of current trends in treating sewage sludge, analyses the potential for generating biogas and hydrogen from sewage sludge, and examines the role of hydrogen in transitioning towards greener energy. The research methodology uses statistical approaches to derive potential values from baseline data through emission factors and categorizes study areas based on this information. The background indicates that biogas-based hydrogen production offers benefits such as utilizing renewable energy sources and reclaiming sewage sludge. There has been a substantial increase in municipal wastewater treatment sludge generation while simultaneously reducing non-hazardous sludge disposal by landfilling. The focus is on utilizing these resources effectively instead of squandering them, while also identifying previously wasted potential over recent years. The primary objective of the paper is to assess the untapped potential that has not been fully utilized in recent years. The research direction was shaped by access to statistical data, albeit constrained by its focus on a typical technological process. The study delves into an increasingly relevant area, with outcomes applicable for policymakers as well as professionals in energy and environmental fields.

The composting of organic and bio-waste is widely practised, and in some regions, it is even a mandatory waste management practice. A valuable by-product of this process is the nutrient-rich liquid known as compost leachate, which holds great potential for use in agriculture and horticulture. This investigation delves into the content, production methods, and impact of compost leachate on different crops while also emphasising its susceptibility to external factors. Compost leachate forms during composting and serves as an effective soil amendment material containing essential nutrients, microorganisms, and humic acids beneficial for plant growth. The quality of this by-product can be compromised by contamination from organic waste materials. Today, there has been widespread adoption of biodegradable or compostable plastic products in household composting systems due to misconceptions or public attitudes towards their usage. In-home composting, the process of decomposition might be slower, and there could be issues with the conventional waste management systems that are still commonly used. Additionally, not all degradable products are exclusively made from natural materials. Sometimes, synthetic polymer chains are utilised to accelerate degradation. This study aims to explore, through a simulated experiment, the possibility of microplastic contamination in composting environments, primarily due to the presence of biodegradable and compostable plastic items in these settings. The research findings indicate that the potential risks of microplastics to compost and compost leachate have been insufficiently explored, only recently becoming a focal point. The key conclusions suggest that the development of strategies to address these ecotoxicological factors is becoming increasingly pressing.

Energy poverty remains one of the key obstacles to sustainable development, directly affecting households and increasingly influencing business operations as well. The research investigates the relationship between energy poverty and greenhouse gas (GHG) emissions in the EU, addressing the often-overlooked connection between social vulnerability, environmental impact, and local climate policy. The study utilizes EU-level indicators to assess energy poverty across member states and develops the Energy Poverty Integral Index (EPII) to quantify it through multidimensional socioeconomic indicators. Building on this, the authors introduce the Energy Poverty and Emissions Index (EPEI), a novel, three-dimensional composite index that integrates (1) energy poverty (via the EPII), (2) residential GHG emissions, and (3) participation in the Covenant of Mayors (CoM), a proxy for local climate policy engagement. By bringing these components together, the EPEI offers a new perspective for examining the intersection of energy deprivation, carbon intensity, and policy responsiveness across the EU. This makes it possible to identify country profiles and policy gaps where high energy poverty coincides with either high emissions or weak climate action. The findings reveal significant correlations between energy poverty and emissions in several EU-27 countries, with strong positive relationships in the Netherlands, Lithuania, and Romania. In contrast, some member states exhibit inverse patterns. Cyprus, Italy, and Germany stand out with the highest energy poverty rates. The study contributes by proposing a standardized framework that links energy poverty to environmental and governance dimensions, supporting more targeted and just climate-energy policy responses in the EU.