The environmental aspects of conventional and clean energy policy in sub-Saharan Africa: is N-shaped hypothesis valid?

Environmental Science and Pollution Research - In the energy-environment literature, a handful of the advanced economies, mostly the European Union countries, have met some of the national...     

Modeling of water quality downgradient of a mulch biowall

Groundwater treatment biowalls may be located close to a surface water body to prevent contaminant discharge from a groundwater plume into the surface water. Groundwater contaminants passing through the biowall are treated within the biowall or immediately downgradient of the biowall. Biowalls designed and constructed for the treatment of chlorinated solvents typically contain either a solid and/or liquid source of organic carbon to promote contaminant degradation by enhanced anaerobic reductive dechlorination. Common solid organic materials in biowalls include wood mulch or similar waste plant material, and common liquid organic materials are vegetable oil (possibly emulsified) or other long‐chain fatty acids. Such biowalls then develop anaerobic conditions in the constructed biowall volume, and potentially downgradient, as dissolved oxygen originally present in the aquifer is consumed. This groundwater condition can lead to the appearance of sulfide if groundwater influent to the biowall contains moderate to high sulfate concentrations. Other researchers have presented evidence for groundwater conditions downgradient of a biowall or a permeable reactive barrier (PRB) that are altered in relation to groundwater quality, besides the desired effect of contaminant degradation or removal by precipitation. The objective of this work was to investigate with modeling the changes in downgradient groundwater species chemistry as a result of a constructed biowall. This was accomplished with a chemical species model to predict levels of sulfate and sulfide present in groundwater in close downgradient proximity to the biowall. The results indicate that downgradient chemical changes could impact a surface water body to which groundwater discharges. The model described could be enhanced by incorporating additional design variables that should be considered in biowall feasibility assessments.     

Recent improvements in oily wastewater treatment: Progress, challenges, and future opportunities

Oily wastewater poses significant threats to the soil, water, air and human beings because of the hazardous nature of its oil contents. The objective of this review paper is to highlight the current and recently developed methods for oily wastewater treatment through which contaminants such as oil, fats, grease, and inorganics can be removed for safe applications. These include electrochemical treatment, membrane filtration, biological treatment, hybrid technologies, use of biosurfactants, treatment via vacuum ultraviolet radiation, and destabilization of emulsions through the use of zeolites and other natural minerals. This review encompasses innovative and novel approaches to oily wastewater treatment and provides scientific background for future work that will be aimed at reducing the adverse impact of the discharge of oily wastewater into the environment. The current challenges affecting the optimal performance of oily wastewater treatment methods and opportunities for future research development in this field are also discussed.     

Pollutant emission effect of tourism,real income,energy utilization,and urbanization in OECD countries: a panel quantile approach

Environmental Science and Pollution Research - Although the Organization for Economic Co-operation and Development (OECD) member countries are largely regarded as a high human development index and...     

Environmental aspect of energy transition and urbanization in the OPEC member states

Environmental Science and Pollution Research - More than any other nations, the crude oil–exporting countries and especially the Organization of the Petroleum Exporting Countries (OPEC) are...     

Do natural resources and economic components exhibit differential quantile environmental effects?

In view of the resource curse assumption, the environmental aspects of resource utilization are arguably posing more dangers to human existence. In the Middle East and North Africa (MENA) region, the region that holds more than 60% and 50% of the world's oil and gas reserves respectively, the need to examine the contribution of natural resources to environmental quality among other factors cannot be overemphasized. By leveraging on the novelty of observing the differential impact of natural resources and other economic components such as income and primary energy utilizations across the quantiles of carbon emission, this study implements the quantile regression approach alongside other relevant techniques to analyze data between 1990 and 2018 for selected countries in the MENA region including Saudi Arabia, Iran, Kuwait, Qatar, Algeria, Morocco, Oman, Egypt, and the United Arab Emirates (UAE). The result posits that natural resource utilization generally hampers the environment across the quantiles. However, this negative effect decreases until the 50th quantile before starting to rise again toward the upper quantiles. Additionally, primary energy utilization and globalization respectively worsen and improve environmental quantile, especially toward the upper quantiles while income affirms the inverted U-shaped hypothesis across the entire quantiles. Moreover, there is a statistically significant one-way directional causality from natural resources, economic expansion, primary energy use, and globalization to carbon emission levels. Hence, the study offers environmentally friendly resource utilization policies to the MENA economies and other resource-rich states by extension.     

Mechanical performance and Taguchi optimization of kenaf fiber/cement-paperboard composite for interior application

Demand for particleboards keeps increasing and as such more trees are fell for its production, engendering deforestation. For the purpose of reducing falling of trees, this study, focused on recycling of waste paper in the development of paperboard as alternative to particleboards used for furniture and interior household applications. Kenaf fiber (KF) was blended at varying proportions of 0, 1, 2, 3, 4, and 5 wt.% with 20 wt.% constant cement and 20 wt.% constant coconut shell powder while the remaining was paper pulp. Board specimen developed were cured for 14, 28, and 90 days and mechanical properties were examined. Results obtained showed that fiber dosage improved bond strength and screw holding strengths as compared with the control mix. Similarly, modulus of rupture was enhanced with KF loading as compared with control mix while 1 to 3 wt.% KF spawned enhancement of modulus of elasticity. However, 4 and 5 wt.% KF led to a reduction in the modulus. Infusion of the fiber enhanced tensile strength from 1 to 3 wt.% content. 14-day and 28-day curing periods were observed to improve properties while the 90-day curing period is detrimental to all properties. Optimization via signal-to-noise ratio revealed an optimum mix of 2 wt.% obtained for fiber and an optimum curing duration of 28 days.

     

Roadmap for climate alliance economies to vision 2030: retrospect and lessons

The United Nations Climate Conference 25, held in December 2019, reached a significant agreement against implementing the Paris agreement come 2020. Bound by the contract, 189 countries who are party to the deal agreed to constrain worldwide temperature to ascend to 1.5° Celsius. To this end, the present study attempts to investigate the readiness of selected countries in the European Union to implement the agreement, which will better the quality of the global environment. In line with this, this study appraises the connection between economic growth, renewable and non-renewable energy consumption, on emissions in 11 countries in the European Union from 1990 to 2016. The study utilises the Pooled Mean Group-Auto Regressive Distributed Lag (PMG-ARDL) model estimator and Dumitrescu and Hurlin Panel Causality analysis to analyse the long-run and short-run impact and direction of causality among these factors, respectively. The long-run study's empirical results show a U-shaped Environmental Kuznets Curve (EKC) and a negative connection between renewable energy use and emissions in the EU-11 countries. In the short-run, non-renewable energy use worsens CO₂ emissions while renewable energy use leads to a fall in emissions. Similarly, causality tests show a feedback mechanism between emissions and renewable energy use and between non-renewable energy and renewable use. Also, there is unidirectional causality from income to CO₂ emissions, non-renewable energy use to CO₂ emissions. The investigation recommends an expanded proportion of renewable energy sources in the EU countries’ energy mix to cut down on emissions.