In recent centuries, water consumption rates have more than doubled and the population growth rate is rising constantly. As a result, water scarcity is now one of the main problems to be faced, mainly in semiarid regions. In light of such a dilemma, this study aims to develop a system dynamics model in order to evaluate the water system in the semiarid region of the state of Paraíba—located in the Brazilian Northeast—and it focus on the following two issues: (1) measures that could have been taken with respect to the recent water crisis (2012–2017); (2) simulating water availability up to 2025. It was observed that, despite the options of in-demand management tools being efficient solutions for water scarcity in the short term (e.g., the influence of scarcity-based tariffs in reducing water use), such tools would not suffice in a context of severe drought within a water-providing system that depends heavily on rainfall. However, certain policies involving water-supply management (e.g., wastewater reuse and inter-basin water transfer) are very effective in maintaining water supply and avoiding a water collapse in the region. Furthermore, employing the Monte Carlo approach in simulating the system dynamic proved that the water supply is sensitive to scarcity-based tariffs, wastewater reuse, and inter-basin water transfer. An important advancement in this study was the simulation of a methodology for pricing that encourages rational use of water-based on its scarcity, which in turn increases revenue and investment in other water-management strategies.

Water extracted from natural sources often requires treatment to meet the quality standards necessary for industrial use, involving physico-chemical processes such as coagulation, flocculation, and sedimentation. Inorganic coagulants, such as aluminum sulfate, are commonly used, although they generate a sludge with residual aluminum, classified as hazardous waste. Given this, biocoagulants, such as natural tannin-based polymers, have emerged as a promising alternative. Thus, the objective of this study was to evaluate the environmental performance of water treatment and sludge disposal at an industrial water treatment plant (WTP) of an oil refinery located in Brazil using aluminum sulfate and biocoagulant. The WTP of this study is located in the state of Bahia, Brazil, and is supplied by a surface water body, the Paraguaçu River—Lago de Pedra do Cavalo—which comes from a semi-arid region, and a lake called Catu Korea. The environmental analysis was carried out using the life cycle assessment (LCA) method, using the methodological framework recommended in ISO 14044, followed by economic analysis and circular economy analysis. The inventory used in the analyses contains field data, company records, related literature, and ecoinvent database version 3.3. The impact assessment considered the ILCD 2011 Midpoint+ method package, the AWARE method, and the cumulative energy demand (CED) method in SimaPro 8.4 software. The comparative results showed the greatest impacts in the Energy Demand, Water Footprint, Eutrophication, and Land Use categories for the biocoagulant scenario, in contrast to the Human Toxicity, Acidification, Ecotoxicity, Particulate Matter, Carbon Footprint, and Abiotic Depletion categories for aluminum sulfate. The economic analysis showed that 65% of the operational costs for material and energy inputs in water treatment are due to the use of electricity, and the water pumping stage is the biggest contributor to this consumption. Even though the price of the biocoagulant was identified as eight times that of aluminum sulfate, the water treatment cost with the biocoagulant was 21% higher compared to that with aluminum sulphate. In this regard, circular economy propositions for sludge valorization are discussed for use, recycling, or proper disposal. Thus, the environmental and economic analysis in this study offers insights into eco-efficiency promotion in water treatment and sludge management.

This study evaluates whether pumped hydro storage (PHS) systems are economically competitive compared to natural gas thermal power plants in meeting peak load demand in Brazil and identifies the barriers and challenges that hinder their widespread adoption. It also examines the strategies, market mechanisms, and policy implications necessary to improve the economic and operational viability of PHS, enabling greater integration of variable renewable energy sources into the Brazilian power system. Using the levelized cost of electricity (LCOE) method, PHS is compared with natural gas thermoelectric plants for peak demand scenarios in Brazil. The results of simulations indicate that PHS is economically viable for operations exceeding seven hours per day, offering lower costs. In contrast, natural gas technologies are more cost-effective for shorter operations. The results provide two key contributions: they characterise the basic conditions under which PHS systems are more competitive than thermal power plants in meeting electricity demand, and they propose a methodology for calculating the LCOE of the analysed technological options, tailored to the Brazilian energy market. The conclusions highlight the potential of PHS to contribute to Brazil’s sustainable energy transition, provided that appropriate policies are implemented. These policies are especially crucial in scenarios where PHS is not economically competitive, to ensure compensation mechanisms for the flexibility services provided and the implementation of carbon pricing. Additionally, retrofitting existing hydropower plants to incorporate PHS components may reduce costs and mitigate environmental impacts compared to constructing new PHS facilities.

The benefits provided by a model of system dynamics are directly related to its correct construction. One of the main challenges in the process of building such models is that they must be able to effectively represent a specific problematic situation. Thus, the main objective of this study is to develop a multi-methodological approach, adapting the problem structuring method of strategic options development and analysis (SODA) in the initial stage of the system dynamics (SD) model. The role of each of them clearly represents the contribution of this study: the SODA in the structuring (representation) phase of the problem and proposition of alternatives and the SD in the evaluation phase of these alternatives. To illustrate its application, the multimethodological approach developed was used to simulate scenarios considering management strategies, and the various variables affecting a water supply system, including population growth, in order to evaluate more “assertive” water management strategy(s) that could have been adopted to address the water crisis (2012–2017) and analysis future scenarios. The results show that, based on the vision of specialists with enough experience for the case studied, it was possible to structure the problem, and therefore propose a set of strategies (alternatives), which were: water loss control, wastewater reuse, application of more efficient tariffs to reduce water waste, inter-basin water transfer, and awareness regarding the use of water resources. After the survey of alternatives, scenarios were simulated considering these water management strategies. Simulation results showed that actions taken on the demand side would only be effective for a short period of water scarcity, (for example, the impact of the scarcity-based tariff on water consumption reduction). For severe drought scenarios and with a water producing system heavily dependent on rainfall, such action would no longer be efficient. However, water supply management-oriented strategies, e.g., inter-basin water transfers (PISF) and wastewater reuse, are highly effective in securing water supply and preventing water supply collapse in the region. The development of this multi-methodological approach is expected to be useful to support managers in the decision-making and implementation of water management strategies.

Given the relevance of sustainability, this study analyzed the impacts on water consumption in the production chain of ornamental stone pieces (marble and granite) and quartz-based composites. The goal was to compare the water demand throughout the process, from extraction to manufacturing, using 1 m³ blocks as the unit of analysis. This study was conducted in Bahia, a state with significant ornamental stone production, located in a semi-arid region with limited water availability. The methodology included data collection from participating companies, combined with sectorial information and the Ecoinvent version 3.3 database, modeled using the SimaPro 8.0 software. The impact assessment was carried out using the AWaRE (Water Scarcity Footprint) and ReCiPe Endpoint methods, following the guidelines of Life Cycle Assessment (LCA), as per ABNT NBR ISO 14040 standards. The results showed that marble and granite have lower water demand and environmental impact in the categories of particulate matter, human toxicity, ecotoxicity, eutrophication, and acidification when compared to quartz composites. The highest environmental impact occurred during the processing stage, which requires a large amount of water and generates effluents, losses, and particulate matter. The results indicate that marble and granite demand less water and exhibit lower environmental impacts—across categories like particulate matter, human toxicity, ecotoxicity, eutrophication, and acidification—than quartz composites. Notably, the processing stage incurred the highest environmental burden due to its intensive water use and consequent generation of effluents, losses, and particulate matter. These findings highlight the necessity of efficient water management and the adoption of circular economy principles—including water reuse and waste valorization—to promote long-term sustainability in the ornamental stone industry.

Estudo socioeconômico do Polo de Confecções no Agreste de Pernambuco: uma análise descritiva e exploratória/ Socioeconomic study of the clothing pole from the Agreste Pernambucano: a descriptive and exploratory analysis