Vanesa Gladys Lo Iacono Ferreira

Smart and sustainable cities are often assessed using indicator-based models. However, most existing systems evaluate cities as a whole, offering limited support for project-level decision-making, particularly in small and medium-sized cities with scarce resources. This study aims to fill this gap by developing a comprehensive indicator framework tailored to the evaluation of smart city projects, designed to guide investment choices and support evidence-based planning. To build this framework, a systematic review of international indicator systems was conducted, compiling and refining over 1200 indicators into a unified taxonomy. The analysis revealed structural imbalances, with environmental and social dimensions prevailing over economic and governance aspects, and confirmed substantial redundancies, with nearly one-third of indicators overlapping. Using project actions as an analytical lens, gaps were detected and 73 evaluation areas defined. From these, anticipated impact indicators were developed and linked to corresponding performance metrics. Beyond consolidating fragmented systems, the framework provides a practical and balanced tool for multidimensional project assessment. An initial empirical pre-validation demonstrated its coverage and usability, reinforcing its potential to support planners and policymakers in comparing investment alternatives. Unlike traditional ranking or maturity models, it directly bridges the gap between abstract smart city strategies and tangible, project-level outcomes.

Nowadays, stricter control and rigorous landfill standards are being promoted in industries that produce liquid discharges into the environment. The development of innovative and sustainable technologies to remove lead from water is of great importance in all aspects, with safe recycling practices, especially with high lead concentrations, such as in mining activities. The experiment was conducted at a reverse osmosis (RO) pilot plant, operated at low impact pressures and designed to optimize energy savings without compromising separation efficiency. By reducing energy consumption, the process not only lowers operational costs but also minimizes the environmental impact associated with high energy consumption. The results show that RO operated at low pressures successfully removed 99.75% of lead at a pressure of 10 bar and a flux of 67.44 L/m²·h, demonstrating a practical and sustainable solution for lead removal at pressures of 5, 7.5, and 10 bar, which are considered low pressures since they are below 1.0 MPa. In addition to its high removal efficiency, the process offers significant advantages in terms of energy efficiency and a reduced carbon footprint. Enhancing the efficiency of this technology is crucial, not only to decrease operational costs but also to reduce environmental impact.

The global challenges that cities must face regarding sustainability, efficiency, integration, and resilience have found in the smart city concept a guideline of action as a model for urban development and transformation. The multidimensional nature of the smart city, along with the importance of identifying key urban stakeholders and ensuring their engagement, are two widely recognized characteristics within the scientific community. However, proposals for the identification, classification, and management of urban stakeholders are very scarce and almost non-existent when considered in conjunction with the holistic nature of smart cities. Thus, the significant importance attributed to stakeholder engagement contrasts with the lack of clear guidelines to develop it properly. Based on an iterative analysis of the scientific literature combined with the cross-referencing of smart city dimensions, statistical analysis tools, and multi-criteria analysis methods, this paper proposes a new methodology for the identification and management of urban stakeholders. The proposal includes a comprehensive classification and a new framework for developing urban stakeholder identification processes at their early stages or the monitoring and assessment of ongoing or completed processes, including tools for analyzing the extent and homogeneity achieved. The practical application of the methodology to a specific case study is also discussed.

Achieving sustainability in life involves increasing efforts to recover resources. This research proposes the recovery of Zn from the Milluni lagoons, an important water supply for Bolivia, where high concentrations of Zn have been identified that exceed permitted limits, exposing a risk to health and ecosystems. The application of reverse osmosis (RO), operated with low pressures, is proposed as a first stage for the concentration of Zn and subsequent recovery of this metal through chemical precipitation. The aim was to maintain the separation efficiency of the RO operated at low pressures without presenting operational problems. As a result, 98.83% metal concentration was achieved with a laboratory-scale pilot system. The above means an important potential for large-scale Zn concentration, apart from orienting the RO toward sustainability by working with low pressures that reduce energy costs during its operation. This study can be used as a valuable reference for the advancement of sustainable technologies in the field of water treatment that simultaneously allow the recovery of resources to promote a circular economy. Finally, this study exposes an alternative for regions with heavy metal water contamination in Bolivia and worldwide.

The accelerated deterioration of water quality in the city of Tarija, Bolivia, has caused several water sources in the Municipality of Tarija to be discontinued due to the presence of toxic contaminants. The current water purification systems that are used in Tarija do not guarantee the elimination of heavy metals; in addition, political and social interest conflicts are a serious problem in the execution of projects and new public investment alternatives, with these being the main problems found in the sector. Reverse osmosis (RO) water purification technologies are one of the most effective contemporary alternatives for the elimination of contaminants in water, such as heavy metals; however, their application and implementation in countries with little or no experience in this type of technology require acceptance and knowledge on behalf of the interested parties. Political and social conflicts between interested parties generate scenarios that affect hydrological planning. Analysis of the actors in the urban and municipal sphere of the city of Tarija, Bolivia, provides a case study for adequate water governance and enabled us to come to a consensus for the implementation of RO. The results show 23 fundamental actors in water management in the Municipality of Tarija, with local actors being those with the greatest influence and power in decision-making. Our analysis of social networks showed an important polarization in the power of decision makers, with municipalities and legislative entities being those that decide on public investments. The interested parties showed considerable interest in the application of RO as a technology that can provide definitive, short-term solutions to the problems of water stress and the water crisis in the Municipality of Tarija and its application in small towns with a high level of social and environmental vulnerability.

Manganese is the Earth’s crust’s third most abundant transition metal. Decades of increased mining activities worldwide have inevitably led to the release of large amounts of this metal into the environment, specifically in water resources. Up to a certain level, manganese acts as an essential micronutrient to maintain health and support the growth and development of microorganisms, plants, and animals, while above a specific limit, manganese can cause toxicity in aquatic and terrestrial ecosystems. There are conventional ways to remove manganese from water, such as chemical precipitation, sorption, and biological methods. However, other treatments have yet to be studied much, such as reverse osmosis (RO), which has demonstrated its effectiveness in the removal of heavy metals and could be a suitable alternative for manganese removal if its energy consumption is reduced. This research presents mathematical and statistical modeling of the behavior of a system in laboratory-scale RO. The principal finding was that it is possible to remove Mn using the RO operated with low pressures without decreasing the sustainable removal efficiency. Reducing the operating costs of RO opens the possibility of implementing RO in different contexts where there are problems with water contamination and economic limitations.