Sequencing batch reactor technology for landfill leachate treatment : a state-of-the-art review

Landfill has become an underlying source of surface and groundwater pollution if not efficiently managed, due to the risk of leachate infiltration into to land and aquifers. The generated leachate is considered a serious environmental threat for the public health, because of the toxic and recalcitrant nature of its constituents. Thus, it must be collected and appropriately treated before being discharged into the environment. At present, there is no single unit process available for proper leachate treatment as conventional wastewater treatment processes cannot achieve a satisfactory level for degrading toxic substances present. Therefore, there is a growing interest in examination of different leachate treatment processes for maximum operational flexibility. Based on leachate characteristics, discharge requirements, technical possibilities, regulatory requirements and financial considerations, several techniques have been applied for its degradation, presenting varying degrees of efficiency. Therefore, this article presents a comprehensive review of existing research articles on the pros and cons of various leachate degradation methods. In line with environmental sustainability, the article stressed on the application and efficiency of sequencing batch reactor (SBR) system treating landfill leachate due to its operational flexibility, resistance to shock loads and high biomass retention. Contributions of integrated leachate treatment technologies with SBR were also discussed. The article further analyzed the effect of different adopted materials, processes, strategies and configurations on leachate treatment. Environmental and operational parameters that affect SBR system were critically discussed. It is believed that information contained in this review will increase readers fundamental knowledge, guide future researchers and be incorporated into future works on experimentally-based SBR studies for leachate treatment

Ridge Penalization-based weighting approach for Eco-Efficiency assessment: The case in the food industry in the United States

Eco-efficiency assessment is of great importance for monitoring and managing environmental and economic aspects of sustainable development. The eco-efficiency indicators are required to assess and measure the impact of multiple environmental aspects per unit of economic value-added. The aggregation of multiple environmental impacts in the presence of high correlation is a critical challenge to sustainability practitioners. This study presents a weighting approach using ridge penalization-based regression to overcoming the consequence of the high correlation among the environmental aspects and hence providing accurate weighting values. The performance of the proposed approach is assessed using economic and environmental footprints of 20 food industries in the United States. The new weighting approach is expected to provide decision-makers with a quantitative management tool for monitoring and controlling core operational functions associated with the sustainable development and management.Scopu

An integrated sustainable quality management framework for quality-related research

The existence of synergies between several quality management systems and sustainability has spurred great interest in better understanding the sustainable quality management (SQM) concept over the past decade. This paper aims to design and develop a sustainable quality management framework (iSQMF) that integrates the quality management practices with the Whole System Design (WSD) practices, including the environmental, social, and economic sustainability aspects. The relevance of the designed iSQMF in supporting quality management research and sustainable initiatives is detailed and reported. In addition, the research presents a twelve-stage planning system as a tool for monitoring and controlling the implementation of SQM programs. The proposed framework holds great potential in not only bringing sustainability concepts actionable but also addressing the institutional and developmental processes in a management system.Scopu

Sustainability Performance of European Smart Cities: A Novel DEA Approach with Double Frontiers

Sustainability is the crux of urban renaissance. Imbibed with utopian technological planning, understanding the convergence between smart development and sustainable practices for city development is necessary. Smart cities have succeeded in bringing high standards of living to its residents. This article evaluates the long-term sustainability performance of 35 leading European smart cities over time from 2015 till 2020 to understand on how these cities address sustainability to make the concept of smart sustainable cities more actionable. A novel Double-Frontier Slack Based Measure Data Envelopment Analysis (DFSBM-DEA) model considering undesirable factors in the technology set is proposed for the assessment. An integrated relative sustainability performance assessment model considering both the optimistic and pessimistic viewpoint simultaneously, in terms of interval efficiency is used to determine the most efficient smart city under 6 various dimensions of sustainable development. These key dimensions include; Energy and Environmental Resource, Governance and Institution, Economic dynamism, Social cohesion and solidarity, Climate Change and, Safety and Security. A productivity progress assessment from a double frontier perspective using a modified Malmquist-DEA model is then used to capture the response of each smart city in terms of their productivity growth towards achieving sustainable development. Results show Dublin (ranked 1st) as the most smart and sustainable European city under all the proposed dimensions of sustainable development from the double-frontier perspective. Along with Dublin lies Oslo, Zurich and Amsterdam as the cities with high aggregate sustainability performance. The results also revealed significant difference in the productivity progress values from the optimistic and pessimistic viewpoint, thus exemplifying the significance for the proposed aggregate productivity progress measurement model. The findings of the present study contribute to knowledge and practice for smart city modellers, decision makers and urban planners, by aiding methodological clarity in assessing sustainable capacity of cities from a double frontier perspective and, in particular, by drawing attention to underlying assumptions about the role of sustainability in smart city development. This research stands as a breakthrough in the field of relative sustainability assessment using non-parametric approaches and a benchmark for global smart cities to shape their development in light of sustainability.Scopu

Arsenic acute toxicity assessment on select freshwater organism species in Malaysia

Recently, arsenic has contaminated the aquatic ecosystem, raising government and public environmental concern. In this study, four freshwater organisms were used to evaluate arsenic toxicity levels. Two types of fish, namely Poecilia reticulata (guppy) (Poeciliidae) and Rasbora Sumatrana (Cyprinidae), an aquatic worm species Tubifex tubifex (Oligochaeta) and diptera midge larvae Chironomus javanus (Chironomidae) were exposed for a 4-day (96 h) period in laboratory conditions to a range of arsenic (As) concentrations. Mortality was assessed and median lethal times (LT50) and concentrations (LC50) were calculated. The objective of this study is to determine the acute toxicity of arsenic concentration on Poecilia reticula, Rasbora sumatrana, Tubifex tubifex and Chironomus javanus. Results showed that LT50 and LC50 increase with the decrease in mean exposure concentrations and times. Results indicated that Tubifex tubifex was most sensitive to arsenic toxicity compared to other organisms used in this study in this order; Tubifex tubifex > Chironomus javanus > Rasbora sumatrana > Poecilia reticulata

A system thinking approach for harmonizing smart and sustainable city initiatives with United Nations sustainable development goals

Technology has indispensably been a part of the city evolution throughout history. In recent years, there has been a shift in the pattern of development in smart cities, where smart cities attempt to embrace practices of sustainability using Information and Communication Technologies and other smart solutions. Past studies reveal that these smart cities have failed in successfully incorporating sustainable development goals into their smart strategies, where they tend to focus more on achieving smartness goals rather than sustainability goals and targets. This paper presents a multi-faceted interrogative study on several ongoing smart city initiatives around the globe that supports United Nations Urban Sustainability Agenda. This paper aims to focus on harmonizing smart and sustainable city initiatives with the United Nations Sustainable Development Goals using a systems thinking approach. The study develops conceptual models that support the city transition into being a sustainable smart city. These conceptual models were designed based on the fundamentals of system thinking for a system of several elements under the key catalyzers ?Policy and Governance,? ?Research & Development,? and ?Partnership.? The causalities and interrelationships among elements in developed conceptual models justify the dynamicity and the impact of these elements within a system. The outcome of this research paper would support industry experts, policymakers, and city planners to adopt robust policy interventions and best practices for developing strategies that support the transition of smart cities to the futuristic label of sustainable cities.Scopu

Carbon footprints across the food supply chain: A microscopic review on food waste-related sustainability assessment

Reducing the carbon footprint along the food supply chain neutralizes the cost of climate change-related impacts on the environment. A third of the food produced globally is wasted along the food value chain. This paper presents a microscopic review covering studies related to carbon footprint analysis across the food industry. The review focuses on the critical aspects of lifecycle-based techniques across the food supply chain, namely, a) calculating the amount of food waste/loss b) evaluating and quantifying the environmental impacts associated with food waste accumulation along the value chain and, c) identifying the stages along the value chain that contribute potentially to the food waste-related emissions and environmental impacts. The results show food waste in terms of mass does not necessarily indicate the food waste-related impact. Although animal-containing products have relatively low waste in terms of mass, they contribute significantly to the food waste-related impact, explicitly affecting global warming potential. This paper's outcomes support food waste-related sustainability assessment and transition to a circular food supply chain.Scopu

5G Networks Towards Smart and Sustainable Cities: A Review of Recent Developments, Applications and Future Perspectives

5G wireless communication systems provide massive system capacity with high data rates, very short low-latency, and ultra-high reliability, in addition to high connection density with a positive experience on smart cities and the Internet of Things (IoT). Future networks are anticipated to revolutionize typical applications such as the enhanced mobile broadband services (EMBB), ultra-reliable low latency communication (uRLLC), and massive machine-type communications (mMTC) anywhere and everywhere. This rationalizes the need to investigate the sustainable elements of 5G networks in smart cities to understand how 5G networks can be more environmentally- friendly and energy-efficient. This paper aims to investigate how 5G networks can act as key enablers in achieving sustainability in smart cities, using a macroscopic review. An overview of 5G communication networks and several 5G technologies used in smart city applications to enhance sustainability is presented. This is followed by investigating the indicators that measure sustainability in 5G networks across the environmental, social, and economic dimensions; and sub-dimensions such as energy efficiency, power consumption, carbon footprint, pollution, cost, health, safety, and security. The results show that the majority of research papers focus on the environmental dimensions of sustainability (42%) when attempting to address sustainability in 5G systems and smart cities. The findings also showed a huge interest in the economic (37%) and social (21%) dimensions as well. Further, when examining the sub-dimensions, it was found that most of the studies focused on energy efficiency (20%), power consumption (17%), and cost (15%).Scopu

An empirical assessment on the transportation sustainability indicators and their impact on economic productivity

Sustainable transportation has been traditionally acknowledged as an accelerating factor in achieving economic productivity. This paper attempts to frame a methodology to study the sustainability of the transportation sector and economy, based on selected key transportation sustainability performance indicators. Previous findings in the literature support the contribution of transportation performance indicators towards achieving economic productivity. This paper examines the dependency of key transportation sustainability indicators on United States economic productivity. The econometric model consisted of performance indicators: a portion of the budget devoted to transportation, per capita traffic congestion delay and, efficient pricing for transportation as the independent variable with per capita GDP as the dependent variable. Three hypotheses were validated using multiple linear regression analysis, with statistical software Minitab 17 and visualized using Tableau http://dx.doi.org/10.0.9. A predictive and what-if analysis was also conducted. The results show a strong correlation between the indicators chosen, highlighting their role in contributing towards overall sustainability.Scopu

Eco-efficiency performance of airlines in eastern Asia: A principal component analysis based sustainability assessment

Bringing sustainability practices to the aviation industry has helped in offsetting carbon emissions to a great extend. However, the question of whether these practices neutralize carbon emissions is yet unanswered. The research presents an eco-efficiency performance analysis on selected seven airlines in Eastern Asia based on data availability using Principal Component Analysis (PCA) as the evaluation technique. The study was carried out with five environmental indicators as inputs (Electricity Consumption, Jet fuel Consumption, GHG emissions, water consumption, and waste generated) and four value-added indicators as the outputs (revenue, passengers, employees, and cargo carried) to compare the sustainability performance levels for the selected airlines. The data related to the airlines required for the assessment was obtained from several database resources, including the GRI, annual airline sustainability reports, ICAO, and IATA. All Nippon Airlines (ANA) is the most eco-efficient and sustainably performing airline in Eastern Asia based on the selected indicators and the obtained datasets. It was observed that there is a discrepancy in the measuring units for the indicators in the metric system used in the published sustainability reports between airlines; thus, collecting complete and consistent data is best recommended to evaluate each airline's sustainability performance from a broader perspective.Scopu