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Study of the Environmental Kuznets Curve in the EU27 Countries Taking into Account Socio-Economic Factors and GHG and PM Emissions.
The study of the relationship between human economic activity and the state of the environment in recent decades is reflected, among others, in the study of the environmental Kuznets curve (EKC) hypothesis. Numerous attempts have been made to examine the existence of the EKC by correlating various measures of environmental devastation with GDP per capita indicators. In this study, the aim and research gap were to compare and confirm/exclude the obtained results with the studies previously conducted by the authors, which referred to the analysis of the EKC in relation to general GHG emissions. In this analysis, GHG emissions per capita were assumed. In recent years, in the EU countries, more and more attention has been paid to research on the EKC focused on GHG emissions, and a certain research gap has been noticed in the direction of EKC analyses for PM2.5 and PM10. In the context of PM emissions, the very negative impact on human health should be emphasized. The authors decided to analyze the EKC hypothesis based on the current available data also in relation to PM emissions. In this study, a group of socio-economic variables in the form of GDP, gross electricity production, passenger cars, and population were used in relation to GHG, PM2.5, and PM10 emissions in the EU-27 countries. The study used multiple regression analysis to test the direction of the relationship between pollutant emissions and GDP. In the case of Germany, a negative correlation was obtained for GHG, PM2.5, PM10 emissions, and GDP. The EKC approach can be successfully used both in system awareness (qualitative) and quantitative studies to prepare scenarios of changes in greenhouse gas and PM emissions and to create strategic planning, manage resources, promote innovation, and in climate policy.
Additives Improving the Efficiency of Biogas Production as an Alternative Energy Source - A Review
Additives for anaerobic digestion (AD) can play a significant role in optimizing the process by increasing biogas production, stabilizing the system, and improving digestate quality. The role of additives largely boils down to, among others, enhancing direct interspecies electron transfer (DIET) between microbial communities, resulting in improved syntrophic interactions, adsorption of toxic substances that may inhibit microbial activity, improving microbial activity, and increasing process stability and accelerating the decomposition of complex organic materials, thereby increasing the rate of hydrolysis. Through the aforementioned action, additives can significantly affect AD performance. The function of these materials varies, from enhancing microbial activity to maintaining optimal conditions and protecting the system from inhibitors. The choice of additives should be carefully tailored to the specific needs and conditions of the digester to maximize benefits and ensure sustainability. In light of these considerations, this paper characterizes the most commonly used additives and their combinations based on a comprehensive review of recent scientific publications, including a report on the results of conducted studies. The publication features chapters that describe carbon-based conductive materials, metal oxide nanomaterials, trace metal, and biological additives, including enzymes and microorganisms. It concludes with the chapters summarising reports on various additives and discussing their functional properties, as well as advantages and disadvantages. The presented review is a substantive and concise analysis of the latest knowledge on additives for the AD process. The application of additives in AD is characterized by great potential; hence, the subject matter is very current and future-oriented.
The use of sewage sludge in anaerobic digestion process: formation, properties, and implementation.
The effect of municipal wastewater treatment, in addition to improving its quality, is sludge formation. Disposal of sewage sludge (SS) is a critical environmental problem that requires careful management. Under current legislation, SS represents waste requiring stabilisation to eliminate pathogenic microorganisms and substances potentially harmful to the environment. Anaerobic digestion (AD) is an efficient method of treating SS, and it produces biogas as a renewable energy source (RES). The efficiency of the process can be increased by combining SS with other organic wastes as cosubstrates. Therefore, AD allows for a twofold benefit crucial for sustainable waste and energy management, i.e. sludge stabilisation and biogas production. Another equally important consideration in the construction of biogas plants at wastewater treatment plants is reducing the plant's operating costs by using the electricity and heat generated in the cogeneration units for the plant's needs. This paper discusses the formation technology and properties of sewage sludge, the legal aspects of using and disposing of SS, the conditions for employing their anaerobic biodegradation, and the co-digestion systems used.
Fundamentals, Operation and Global Prospects for the Development of Biogas Plants-A Review
As the global demand for renewable energy continues to rise, biogas production has emerged as a promising solution for sustainable energy generation. This review article presents the advantages of biogas technologies (mainly agricultural, based on waste of animal and plant origin) and extensively discusses the main principles of biogas production in the anaerobic digestion (AD). In this respect, the main parameters of the process, which require monitoring and decisive for its efficiency are described, therefore: temperature, pH value, retention time and organic loading rate (OLR). The principles of substrate selection are also discussed and the necessity and advantages of the use of organic waste according to the model of a circular economy and the concept of sustainable development, are indicated. It is emphasized that according to the new European regulations, the crops classified as food cannot be considered energy crops. The part on biogas production is summarised with an explanation of the necessity to treat and purify biogas. Biogas purification is important from the point of view of the efficiency of its conversion into electricity. A special place in this paper is devoted to the design, construction, functioning and operation of biogas plants, based on both scientific and practical aspects. In conclusion of this chapter, the economic aspects and profitability of operating biogas plants are discussed. Cost and benefit analyses are the major tool used for the systematic evaluation of the financial costs and potential benefits associated with the operation of biogas plants. The important fact is that the return on investment can be achieved within a few years, provided the activities are well-planned and executed. In addition to the fundamental issues of the operation of biogas plants, this article presents the global situation regarding the development of biogas plants, discussing in detail the specific needs and limitations on different continents. It is a interesting and extensive part of this article. The global agricultural biogas market is at very different levels of development. Most such installations are located in Asia and Europe. China has the highest number of biogas plants, with more than 100,000 biogas plants, followed by Germany with over 10,000 plants. In addition to the 100,000 biogas plants, China also has a large number of household biogas units, which gives a total of approx. 40 million operating units. The article concludes with a discussion of opportunities and barriers to the development of biogas plants, pointing to: financial issues, access to feedstock, political regulations, public awareness and the geopolitical situation. The most frequently cited reasons for investment failure include economic problems, lack of professional knowledge.
Operation and challenges of biogas technology: a fundamental overview
The modern world is facing a huge energy crisis related to the depletion of conventional energy sources. Therefore, obtaining energy from alternative sources is sparking increasing interest, expressed by both scientists and entrepreneurs. One such source is biogas, which has great potential to become, along with wind and solar energy, an important renewable energy source (RES). This paper presents the technical and practical aspects of biogas production (mainly agricultural) and extensively discusses the anaerobic digestion (AD) process. The global development of biogas plants and the operation of the most important types of biogas plants are also discussed. In the conclusion section, the benefits of biogas technology development are provided and explained, as well as the challenges and barriers hindering the intensification of biogas plant construction despite the potential and access to adequate resources and waste materials.