Wastewater Management: Bibliometric Analysis of Scientific Literature

Water Markets: Mapping Scientific Knowledge

Water is a vital resource for citizens’ economic and social development. However, the uses to which it can be put often conflict. Possible solutions to mitigate disputes involve political options, scarce economic resources, and the search for mechanisms to ensure its adequate allocation. For over half a century, countries such as Australia, Spain, Chile, and the western states of the United States have been considering the possibility of using markets for rights of use. They are defined as formal or informal trading exchanges of rights, whose aim is to improve efficiency, ensure security of supply, and make allocations more flexible. In this context, the aim of this article is to show a current picture of the scientific production related to Water Markets using the comparative bibliometric study of the documents indexed in the Web of Science (WoS) and Scopus databases as a tool. The advanced search of relevant terms resulted in the retrieval of 261 papers from WoS and 305 from Scopus, with a time limit of 2020, which make up the ad hoc basis of the analysis. From this basis, it can be deduced that the subject of the Water Market has been present in the scientific literature on a more or less regular basis since the beginning of the 1990s. However, it has emerged as a topical issue in recent years, being in a phase of exponential growth, which means that interest in the area is likely to continue in the coming years.

Transition towards Sustainable Carwash Wastewater Management: Trends and Enabling Technologies at Global Scale

Carwash wastewater (CWW) contains grease, oil, hydrocarbon residues, heavy metals, and surfactants, posing severe impacts to the environment and human health. Accordingly, various physical, chemical, and biological processes for CWW treatment have been demonstrated in recent research. In this study, a bibliometric approach was performed to comprehensively illustrate the recent progress, current direction, and future perspectives of CWW-related research. A keyword co-occurrence network was used to represent the results of the bibliometric analysis and to show the major pollutants in CWW effluents and the common systems for treating CWW via coagulation/flocculation, electrochemical, oxidation, membrane, adsorption, biological, and hybrid methods. An integrated anaerobic digestion/oxidation process has been reported to degrade CWW-associated pollutants and help develop an energy-efficient approach for waste management. The results demonstrated that the treatment of CWW has several benefits relevant to sustainable development, viz., good health and well-being, protection of life below water, bioenergy generation, and community awareness and acceptance towards wastewater reuse. Hence, these benefits could assist in meeting the environmental, economic, and social sustainable development goals (SDGs). These study outputs can encourage policymakers and stakeholders in implementing sensible regulations that control water usage and treatment in car sharing and personal vehicle services to either directly or indirectly adopt the agenda 2030 with its seventeen SDGs.

The Imperative Need of Metal Salt for the Treatment of Industrial Wastewater via the Synergic Coagulation-Flocculation Method

Tile industry wastewater is known to contain a high concentration of TSS and turbidity resulting from various raw materials. In the present study, the effectiveness of the coagulation process on turbidity and TSS removal from Kuwait ceramic tile industry wastewater was investigated using ferric chloride as a coagulant. The experiments were conducted using jar tests to determine the optimum operating conditions of coagulant dosages, pH, and settling time. It was found that the coagulant dosage and medium pH greatly affect the efficiency of the coagulation process. A gradual increase in coagulant dosage from 10 to 50 mg/L increased the efficiency of turbidity removal from 95.6% to 99.5%. The efficiency of the coagulation process was also found to be dependent on pH values, where higher pH improved the efficiency of turbidity removal. It was found that a medium pH of 10, 1 h settling time, and 50 mg/L of coagulant dosage are the optimum process conditions to achieve almost complete removal of turbidity (99.5%) and TSS (99.8%). This study concluded that coagulation might be useful as a primary wastewater treatment process for tile industry wastewater.

Bibliometric Analysis of Groundwater’s Life Cycle Assessment Research

Groundwater is an important water resource that accounts for 30% of the world’s freshwater. 97% of this extracted groundwater is for drinking and human use. Due to anthropogenic activities, this resource is affected and, consequently, its life cycle is modified, changing its natural state. This paper aims to analyse the scientific production that deals with the study of groundwater’s Life Cycle Assessment (LCA), using bibliometric methods. Thus, it contributes to the evolution of knowledge of this resource in terms of its use (environmental, economic and social). The methodological process includes: (i) selection and analysis of search topics in the Scopus and Web of Science (WoS) databases; (ii) application of Bibliometrix and Visualisation of Similarity Viewer (VOSviewer) software to the data collected; (iii) scientific structure of the relation of the topics groundwater and life cycle, considering programme lines and relations in their sub-themes; (iv) literature review of Author keywords. A total of 780 papers were selected, 306 being from Scopus, 158 from WoS and 316 published in both databases. The time evolution of the analysed data (publications) indicates that groundwater LCA studies have seen exponential growth (between 1983 and 2021). In addition, it has three development periods: introduction (years between 1983 and 2001), growth (between 2002 and 2011) and maturation (between 2012 and 2021). At the country level (origin of contributions authors), the USA dominates the total scientific production with 24.7%, followed by Denmark with 12.8% and 10.3% for China. Among the main topics of study associated with LCA are those focused on: the proposal of remediation methods, the application and development of technologies and the use of water resources by the urban community. This study allows establishing new trends in agricultural development issues about irrigation efficiency, wastewater reuse, mining and treatment, climate change in a circular economy scheme related to sustainability and life cycle assessment.

Worldwide Research Trends in Landslide Science

Landslides are generated by natural causes and by human action, causing various geomorphological changes as well as physical and socioeconomic loss of the environment and human life. The study, characterization and implementation of techniques are essential to reduce land vulnerability, different socioeconomic sector susceptibility and actions to guarantee better slope stability with a significant positive impact on society. The aim of this work is the bibliometric analysis of the different types of landslides that the United States Geological Survey (USGS) emphasizes, through the SCOPUS database and the VOSviewer software version 1.6.17, for the analysis of their structure, scientific production, and the close relationship with several scientific fields and its trends. The methodology focuses on: (i) search criteria; (ii) data extraction and cleaning; (iii) generation of graphs and bibliometric mapping; and (iv) analysis of results and possible trends. The study and analysis of landslides are in a period of exponential growth, focusing mainly on techniques and solutions for the stabilization, prevention, and categorization of the most susceptible hillslope sectors. Therefore, this research field has the full collaboration of various authors and places a significant focus on the conceptual evolution of the landslide science.

Bibliometric Mapping of Research on Magic Towns of Mexico

The tourism program “Pueblos Mágicos” was created in 2001 by the Mexican Secretary of Tourism (Sectur), together with its brand, with the aim of promoting tourism by preserving secular and ancestral traditions, as well as revitalizing cities and towns that make great efforts to protect and safeguard their cultural wealth. In this context, the aim of this research work is to show the current state of scientific research carried out within the context of the Magic Towns of Mexico. The work methodology is based on the bibliometric analysis of the scientific production indexed in two main international databases: Web of Science and Scopus. The application of this technique will make it possible to obtain a scientific mapping of the production (growth, researchers in the subject, production impact through the number of citations, network analysis, etc.), with the aim of observing the evolution in the generation of knowledge regarding this tourism development tool that acts as a distinctive brand for tourism in Mexico. This mapping is useful for researchers as it provides information on the research carried out so far, allowing them to identify gaps to work on in their future research work. The systematic search process identified 52 articles. The results indicate that the research carried out in this context is incipient, with few researchers addressing the subject on a continuous basis and most of them being transient researchers with a single article. Most of the research was approached from the perspective of cultural heritage, cultural resources, inherited resources, cultural tourism, public policy, local development and sustainable tourism, and sustainable development. In light of the number of articles published, all of these can be considered to be incipient lines of research.

Water Utilities Challenges: A Bibliometric Analysis

The water utilities are under big pressure to guarantee water access to their customers with the right level of service and quality due to challenges such as climate change, aging infrastructure, water scarcity, and growing populations, which put pressure on their operations. The scientific community has worked intensively over the last years to propose solutions and alternatives for the utilities to improve their operation and management in order to overcome these challenges. This paper aims to review scientific contributions to this field. The result shows increasing awareness from the scientific community in this topic which translates into a growing number of publications since the beginning of the current century. This paper analyzes the evolution of the publications, identifies the main countries and institutions working in this field and their scientific relationships over time. It also identifies the main keywords in the literature, which are grouped into three main topics: water quality, water management, and water optimization. The development of smart technologies is accelerating the scientific production towards the topic of water optimization, which is acquiring more importance over the last years. Future trends of research are related to identifying specific challenges per country and the specific solutions proposed by the scientific community to address them and its feasibility to be applied in other places.

Wastewater Refinery: Producing Multiple Valuable Outputs from Wastewater

A wastewater refinery is a multifunctional solution that combines different technologies and processing schemes to recover a spectrum of valuable materials from municipal or industrial wastewater. The concept of wastewater refinery introduces a new perspective on wastewater treatment and management. It aims at making the most of wastewater constituents by co-producing different worthful outputs, such as water, energy, nitrogen, sulfide, and phosphorous. This can turn the treatment of wastewater from a major cost into a source of profit. The wastewater refinery approach is well aligned with the concept of the circular economy. A case study on Qatar’s wastewater revealed the potential recovery of significant quantities of valuable resources embodied in the country’s wastewater. Valorization of organic constituents and the recovery of nitrogen, phosphorus, and sulfide should be given priority. To facilitate the adoption of the wastewater refinery concept, research is required to explore technical and economic bottlenecks.

Worldwide Research on Geoparks through Bibliometric Analysis

Since the Digne Convention in 1991, the literature related to Geoparks has gained a growing interest on the academy’s part, especially in achieving the preservation of geological interest sites through sustainable tourism. This article aims to provide an analysis of the academic research on Geoparks, based on publications in the Scopus database in the period 2002–2020. Bibliometric analysis methods and bibliographic display maps were examined using VOSviewer software. The bibliometric analysis process comprises three phases: (i) Search Criteria and Source Identification, (ii) software and data extraction, and (iii) data analysis and interpretation. The results show geoparks in full growth as a scientific discipline, thanks to the contribution of various authors, institutions, journals, and related topics that confirm the importance of this field of study. Additionally, bibliometric maps lead to an understanding of the intellectual structure of the subject, in which keyword co-occurrence analysis shows six main themes, ranging from ‘UNESCO Global Geoparks’ to ‘Geo-tourism-Sustainable Tourism’. this, combined with maps of co-citation, broadly exhibits this structure and development, showing areas of current interest and potential development, thus offering the latest knowledge on Geopark research worldwide. There is a growing concentration of research on geomorphological heritage and geo-tourism, focusing on methodologies to evaluate the specialities of this type of heritage and define the concept of geo-tourism; there is a great interest especially in the evaluation and identification of geo-site/geo-morphosites which try to eliminate subjectivity in methods and focus on sustainable development of the localities.