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This paper analyzes the impact of methane emissions taxation on the recovery of the investments required for implementing technologies that use biogas energy in small wastewater treatment plants (WWTPs) in Brazil. It is based on the hypothesis that the adoption of a national methane emission tax policy would encourage small WWTPs to become sustainable power plants. The procedure involved 173 anaerobic plants to analyze: (a) methane production; (b) available useful energy; (c) investments and avoided costs for implementing STHIL system (thermal drying sludge) and motor generator (electricity generation); (d) financial impact for two scenarios (C1: no emissions tax; C2: with tax). Positive environmental and financial results were observed for WWTPs, varying according to the period of time analyzed for both technologies. Investments must be made in cogeneration in anaerobic WWTPs for achieving satisfactory results. Taxation must not be viewed simply as a punitive instrument; on the contrary, it should be seen as a tool to encourage continuous process improvement. The circular economy may support the enlargement of the wastewater collection and treatment system, guaranteeing widespread sanitation conditions in urban areas. However, the actual implementation of a methane emission tax in Brazil still requires many rounds of discussion among sanitation companies, government, and civil society, to establish emission limits, and unit taxes, as well as to consolidate a carbon trade to follow through with this decision in the sanitation sector. [ABSTRACT FROM AUTHOR]

Sustainability is one of the most significant aims strived to achieve. Energy and the environment are interrelated factors that contribute to sustainability. Measuring energy and environmental sustainability is of utmost importance. The paper's aim is to analyze the energy and environmental performance of the G20 members. An integrated approach with MCDM methods is proposed. First, we attribute criteria weight via the CRITIC method. Secondly, we evaluate the performance of the G20 countries via the VIKOR and CoCoSo methods. Our results show that Brazil is ranked as the G20 country with the best performance. We may conclude that performance evaluation via MCDM methods may give significant insight into the sustainable development of countries. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to analyse recent actions of energy efficiency implemented by University of Passo Fundo, a higher education institution located in the south of Brazil, and their contributions to Goal 7. Design/methodology/approach: The analysis is based on collected energy data and information of energy efficiency actions applied at the university. Findings: The paper shows the progress related to the energy practices and discusses opportunities, threats, strengths and weaknesses of applying energy efficiency at universities and its contributions towards sustainable development goal (SDG) 7. Practical implications: The findings of this study can inform readers about University of Passo Fundo's initiatives towards energy efficiency focussed in lightening, photovoltaic solar power generation and free energy market. Readers are able to improve their knowledge with the discussion of internal and external factors related to the initiatives. Originality/value: The originality of this paper is connected to the idea of sharing the experiences from University of Passo Fundo, connecting energy efficiency practices at universities to SDG 7 and also exploring opportunities, threats, strengths and weaknesses of applying these practices in the context of a higher education institution. [ABSTRACT FROM AUTHOR]

Brazil is a leader in the production of biodiesel, and some challenges still exist in improving the energy usage and feedstocks alternatives for the transesterification process. In this paper, an industrial scale simulation was conducted to show a comparison of the traditional alkali-catalyzed process using catalysis sodium hydroxide with an enzyme-catalyzed process novel developed by the research team of one of the authors. LCA methodology was used to evaluate the potential multiple effects on the environment in Brazilian scenarios. In this regard, three basic cases were carried out: Case 1, where 1 t of soybean biodiesel was produced from the alkali-catalyzed process; Case 2 and 3, where 1 t of biodiesel, using the enzyme-catalyzed process, was produced from soybean oil and waste cooking oil respectively. The results reveal that considerable contribution can be made to the environment in Case 3 when waste cooking oil (WCO) is considered as a nearly environment-burden-free resource. Additionally, as illustrated in Case 2, not only the feedstock but also the technologic process can generate great influence on the environment when producing biodiesel in a large-scale plant. The efficiency of electric and thermal energy usage should be appropriately considered to diminish these impacts as much as possible. Likewise, chemicals and waste disposal also need to be well managed. [ABSTRACT FROM AUTHOR]