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Topic Review
Microbial Fuel Cells in Treatment  from Wastewater
The treatment of wastewater is an expensive and energy-extensive practice that not only ensures the power generation requirements to sustain the current energy demands of an increasing human population but also aids in the subsequent removal of enormous quantities of wastewater that need to be treated within the environment. Thus, renewable energy source-based wastewater treatment is one of the recently developing techniques to overcome power generation and environmental contamination issues. In wastewater treatment, microbial fuel cell (MFC) technology has demonstrated a promising potential to evolve as a sustainable approach, with the simultaneous recovery of energy and nutrients to produce bioelectricity that harnesses the ability of electrogenic microbes to oxidize organic contaminants present in wastewater. 
  • 2.1K
  • 18 Jan 2023
Topic Review
Astrooceanography
Astrooceanography is the study of oceans outside planet Earth. Unlike other planetary sciences like astrobiology, astrochemistry and planetary geology, it only began after the discovery of underground oceans in Saturn's Titan and Jupiter's Ganymede. This field remains speculative until further missions reach the oceans beneath the rock or ice layer of the moons. There are many theories about oceans or even ocean worlds of celestial bodies in the Solar System, from oceans made of diamond in Neptune to a gigantic ocean of liquid hydrogen that may exist underneath Jupiter's surface. Early in their geologic histories, Mars and Venus are theorized to have had large water oceans. The Mars ocean hypothesis suggests that nearly a third of the surface of Mars was once covered by water, and a runaway greenhouse effect may have boiled away the global ocean of Venus. Compounds such as salts and ammonia dissolved in water lower its freezing point so that water might exist in large quantities in extraterrestrial environments as brine or convecting ice. Unconfirmed oceans are speculated beneath the surface of many dwarf planets and natural satellites; notably, the ocean of the moon Europa is estimated to have over twice the water volume of Earth. The Solar System's giant planets are also thought to have liquid atmospheric layers of yet to be confirmed compositions. Oceans may also exist on exoplanets and exomoons, including surface oceans of liquid water within a circumstellar habitable zone. Ocean planets are a hypothetical type of planet with a surface completely covered with liquid. Astrooceanography is closely related to Astrobiology, as oceans are expected to have higher chances to house simple forms of life.
  • 2.0K
  • 01 Nov 2022
Topic Review
Submarine Canyon
A submarine canyon is a steep-sided valley cut into the seabed of the continental slope, sometimes extending well onto the continental shelf, having nearly vertical walls, and occasionally having canyon wall heights of up to 5 km, from canyon floor to canyon rim, as with the Great Bahama Canyon. Just as above-sea-level canyons serve as channels for the flow of water across land, submarine canyons serve as channels for the flow of turbidity currents across the seafloor. Turbidity currents are flows of dense, sediment laden waters that are supplied by rivers, or generated on the seabed by storms, submarine landslides, earthquakes, and other soil disturbances. Turbidity currents travel down slope at great speed (as much as 70 km/h), eroding the continental slope and finally depositing sediment onto the abyssal plain, where the particles settle out. About 3% of submarine canyons include shelf valleys that have cut transversely across continental shelves, and which begin with their upstream ends in alignment with and sometimes within the mouths of large rivers, such as the Congo River and the Hudson Canyon. About 28.5% of submarine canyons cut back into the edge of the continental shelf, whereas the majority (about 68.5%) of submarine canyons have not managed at all to cut significantly across their continental shelves, having their upstream beginnings or "heads" on the continental slope, below the edge of continental shelves. The formation of submarine canyons is believed to occur as the result of at least two main process: 1) erosion by turbidity current erosion; and 2) slumping and mass wasting of the continental slope. While at first glance, the erosion patterns of submarine canyons may appear to mimic those of river-canyons on land, due to the markedly different erosion processes that have been found to take place underwater at the soil/ water interface, several notably different erosion patterns have been observed in the formation of typical submarine canyons. Many canyons have been found at depths greater than 2 km below sea level. Some may extend seawards across continental shelves for hundreds of kilometres before reaching the abyssal plain. Ancient examples have been found in rocks dating back to the Neoproterozoic. Turbidites are deposited at the downstream mouths or ends of canyons, building an abyssal fan.
  • 2.0K
  • 09 Nov 2022
Topic Review
Aquatic Ecology of Southern African Watersheds
Southern Africa (SA) is rich in large river basin networks, from the over 1.4 million km2 Zambezi River Basin in the upper parts and extending further to the 0.4 million km2 Limpopo and 0.9 million km2 Orange River Basin systems southwards. Given that most SA river basins hold vast mineral deposits, the mining waste generated by artisanal and mechanised mining industries has significantly affected the health of its aquatic ecosystems.
  • 2.0K
  • 17 Feb 2022
Topic Review
Groundwater Remediation Technologies
Groundwater contamination is one of the most concerning issues from uranium mining activities. Radionuclides cannot be destroyed or degraded, unlike some organic contaminants (and similar to metals). Besides, sites, where radionuclides may be found, are mainly radioactive and mixed waste disposal areas, and therefore many other contaminants may also be present in groundwater.
  • 2.0K
  • 05 Jul 2021
Topic Review
Probiotics for Freshwater Fish Farming
Probiotics for freshwater fish farming can be administered as single or multiple mixtures. The expected benefits of probiotics include disease prophylaxis, improved growth, and feed conversion parameters, such as the feed conversion rate (FCR) and specific growth rate (SGR).
  • 2.0K
  • 20 Dec 2021
Topic Review
Driving Forces behind Climate Change
Climate change occurs through a complex set of interactive driving forces. According to the Intergovernmental Panel on Climate Change sixth assessment report (AR6; https://wg1.ipcc.ch/index.php/ar6/sixth-assessment-report-ar6; Accessed on 5 November 2022), human activity is the main driving force of climate change, whereas others contend that natural factors are also main causes.
  • 1.9K
  • 06 Dec 2022
Topic Review
Crop Plants with Silicon Application
Silicon (Si) is present in soil mainly in three different phases such as solid, liquid, and adsorbed. Solid phases can be either amorphous or crystalline. Plants take up Si from the soil which impacts their growth and nutrient accumulation. It increases plant resistance to abiotic and biotic stresses such as drought, salinity, and heavy metal, diseases, and pest infestation.
  • 1.9K
  • 29 Apr 2022
Topic Review
Membrane Biofouling
Water scarcity is an increasing problem on every continent, which instigated the search for novel ways to provide clean water suitable for human use; one such way is desalination. Desalination refers to the process of purifying salts and contaminants to produce water suitable for domestic and industrial applications. Due to the high costs and energy consumption associated with some desalination techniques, membrane-based technologies have emerged as a promising alternative water treatment, due to their high energy efficiency, operational simplicity, and lower cost. However, membrane fouling is a major challenge to membrane-based separation as it has detrimental effects on the membrane’s performance and integrity. Based on the type of accumulated foulants, fouling can be classified into particulate, organic, inorganic, and biofouling. Biofouling is considered the most problematic among the four fouling categories.
  • 1.9K
  • 27 Dec 2022
Topic Review
Recent Advances in Membrane Distillation Module Configurations
Membrane Distillation (MD) is a membrane-based, temperature-driven water reclamation process. While research emphasis has been largely on membrane design, upscaling of MD has prompted advancements in energy-efficient module design and configurations. Apart from the four conventional configurations, researchers have come up with novel MD membrane module designs and configurations to improve thermal efficiency. While membrane design has been the focus of many studies, development of appropriate system configurations for optimal energy efficiency for each application has received considerable attention, and is a critical aspect in advancing MD configurations. This review assesses advancements in modified and novel MD configurations design with emphasis on the effects of upscaling and pilot scale studies. Improved MD configurations discussed in this review are the material gap MD, conductive gap MD, permeate gap MD, vacuum-enhanced AGMD/DCMD, submerged MD, flashed-feed MD, dead-end MD, and vacuum-enhanced multi-effect MD. All of these modified MD configurations are designed either to reduce the heat loss by mitigating the temperature polarization or to improve the mass transfer and permeate flux. Vacuum-enhanced MD processes and MD process with non-contact feed solution show promise at the lab-scale and must be further investigated. Hollow fiber membrane-based pilot scale modules have not yet been sufficiently explored. In addition, comparison of various configurations is prevented by a lack of standardized testing conditions. We also reflect on recent pilot scale studies, ongoing hurdles in commercialization, niche applications and energy efficiency of the MD process.
  • 1.8K
  • 28 Jan 2022
Topic Review
Treatment Methods for Dye-Contaminated Effluents
Advancements in textile dyeing technologies have introduced novel categories of dyes that have deleterious effects on ecosystems. Primarily, azo dyes represent the majority of synthetic dyes employed in textiles and in the realms of culinary and miscellaneous applications. Traditionally, these dyes infiltrate the environment via discharged contaminated effluents such as wastewater from industrial facilities. The contaminated discharged effluent exerts a pervasive impact on ecosystems, engendering pernicious afflictions in both human and faunal populations. Several treatment methodologies are employed for the eradication of contaminants from natural water resources and wastewater, encompassing all phases within water and wastewater treatment infrastructures. The evolution of each treatment stage is intricately linked to the escalating demand for potable water of impeccable quality. Water treatment methods such as Coagulation and Flocculation, Photocatalytic Degradation, Ion Exchange, Electrochemical Technique, Membrane Filtration, Electrodialysis Process, Biodegradation Techniques, and Adsorption are covered in detail, alongside the impacts of bio-based activated carbon as an adsorbent for azo dye. 
  • 1.8K
  • 26 Sep 2023
Topic Review
Plastic Food Packaging: Consumer Perspective
The use of plastics for packaging has some advantages, since they are flexible and inexpensive. However, most plastics are of single use, which, combined with low recycling or reuse ratios, contributes substantially to environmental pollution. This work is part of a project studying the habits of Portuguese citizens concerning plastic food packaging and focuses on aspects related to sustainability. The survey was carried out via an online questionnaire about sustainability, recycling, and knowledge of the effects of plastic materials or their residues on the environment. The results were obtained based on a statistical analysis of the data. The participants tend to think about the negative impact of plastic packages on the environment; 39% sometimes do not buy plastic; and 30% try to look for alternatives. A substantial fraction, 81%, support the avoidance of plastic utensils and reduction in the use of plastic bags. Most participants have a good knowledge of recycling and strongly agree with the use of recycled materials, and 87% of respondents practice separation of different types of waste for recycling. Changing plastic consumption habits has not been an easy task. Nevertheless, it is expected that society will increasingly move toward sustainable habits, questioning its actions and considering their impact on the environment.
  • 1.8K
  • 13 Sep 2021
Topic Review
Wastewater Fecal Pollution Management
Global water scarcity has led to significant dependence on reclaimed or recycled water for potable uses. Effluents arising from human and animal gut microbiomes highly influence water quality. Wastewater pollution is, therefore, frequently monitored using bacterial indicators (BI).
  • 1.8K
  • 16 Dec 2022
Topic Review
Ecosystem Services of Constructed Wetlands for Wastewater Treatment
Constructed wetlands (CWs) are nature-based solutions that utilize natural vegetation, soils, and microbes to treat domestic wastewater and industrial effluents. They are engineered treatment systems that mimic the functions of natural wetlands to capture stormwater, reduce nutrient loads, and create diverse wildlife habitats. As an ecosystem, CWs contribute to human well-being by providing certain ecosystem services that can be classified into four distinct categories, namely: provisioning services, regulating services, supporting services, and cultural services.
  • 1.8K
  • 01 May 2023
Topic Review
Groundwater Level Modeling with Machine Learning
Groundwater is the largest global reservoir of liquid freshwater, which is under increasing stress due to overdraft. Groundwater is a vital source of freshwater, supporting the livelihood of over two billion people worldwide. The quantitative assessment of groundwater resources is critical for sustainable management of this strained resource, particularly as climate warming, population growth, and socioeconomic development further press the water resources. Rapid growth in the availability of a plethora of in-situ and remotely sensed data alongside advancements in data-driven methods and machine learning offer immense opportunities for an improved assessment of groundwater resources at the local to global levels.
  • 1.8K
  • 06 Apr 2022
Topic Review
AOPs for Water Treatment
Advanced oxidation processes (AOPs) are water treatment processes that are promising for the degradation of persistent or toxic organic pollutants, as well as compounds refractory to other environmental remediation/decontamination treatments. AOPs have gained great importance as alternative treatment processes that affect the degradation of organic species through the action of the hydroxyl radical (OH), oxidizing pollutants present in wastewater and industrial effluents. AOPs are carried out at room temperature and at a pressure close to normal, which involve the formation of very reactive radical species with a high oxidizing capacity, mainly hydroxyl (OH) radicals. These OH radicals are extremely reactive oxidizers (oxidation potential of the OH radical is approximately, Eθ = 2.8 V) and non-selective towards organic pollutants in wastewater. AOPs can be considered versatile technologies, as they provide different possible alternatives to produce OH radicals. AOPs, compared to conventional water treatment techniques, have a greater efficiency and capacity to degrade recalcitrant organic pollutants, and can generate less toxic intermediate products during their degradation.
  • 1.8K
  • 03 Sep 2021
Topic Review
Hydrochar for Potential Wastewater Treatment Applications
In today’s world, due to population increase, there are many alarming and potential catastrophic problems like climate change, environmental pollution and an enormous mass of wastes constantly produced by humankind to find innovative solutions for the management, recycling, and valorization of biowaste from agricultural production, food processing, and organic household residues. The search for sustainable and efficient wastewater treatment technologies has gained scientific interest; particular focus is on using biowaste to produce hydrochars (HCs) via the hydrothermal carbonization (HTC) process used as adsorbent materials for dye, heavy metal, and emerging pollutant removal. HTC materials derived from renewable resources are an environmentally friendly and adequate way to adsorb pollutants such as organic and inorganic molecules from wastewaters. 
  • 1.7K
  • 10 Aug 2022
Topic Review
Agricultural Drainage
Practicing agricultural drainage strategies is necessary to manage excess water in poorly drained irrigated farmlands to protect them from induced waterlogging and salinity problems. 
  • 1.7K
  • 16 Jan 2023
Topic Review
Wastewater Treatment in Developing Nations
Water is the founding fundamental of life and hence is a basic need of life. Due to poor water quality and sanitation problems, most health issues are caused by water-borne infections. In developing countries, untreated wastewater is released into water bodies or the ground, thereby polluting natural resources. This is due to the lack of sufficient infrastructure, planning, funding, and technologies to overcome these problems. Additionally, the urbanization of megacities in developing countries is highly accelerated, but it is disproportionate to the required resources for treating wastewater. 
  • 1.7K
  • 31 Aug 2022
Topic Review
Desalination Pretreatment Technologies
Pretreatment of raw feed water is an essential step for proper functioning of a reverse osmosis (RO) desalination plant as it minimizes the risk of membrane fouling. Conventional pretreatment methods have drawbacks, such as the potential of biofouling, chemical consumption, and carryover. Non-conventional membrane-based pretreatment technologies have emerged as promising alternatives.
  • 1.7K
  • 11 May 2023
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