Removal and recovery of phosphate from water using sorption

Sorption is an effective, reliable, and environmentally friendly treatment process for the removal of phosphorus from wastewater sources which otherwise can cause eutrophication of receiving waters. Phosphorus in wastewater, if economically recovered, can partly overcome the future scarcity of phosphorus resulting from exhaustion of natural phosphate rock reserves. The authors present a comprehensive and critical review of the literature on the effectiveness of a number of sorbents, especially some novel ones that have recently emerged, in removing and recovering phosphate. Mechanisms and thermodynamics of sorption, as well as regeneration of sorbents for reuse using acids, bases, and salts, are critically examined. © 2014 Copyright Taylor & Francis Group, LLC

Analysis of the Samus Collimeter Cart

The SAMUS collimator cart is a support for shielding blocks and the vacuum assembly of the Tevatron beam tube as it passes through the D0 End Iron. It slides on linear bearings mounted in the SAMUS toroid as the End Iron moves in and out. There are two collimators designed for the D0 experiment, designated North and South, each identical except for the shimming of the tungsten center blocks, and thereby the relative position of the Tevatron tube. This report contains calculations of the stresses during installation as well as the installed configurations. To support the analysis of the installation case, loads were simulated on the cart held in a mock-up of the lifting fixture

Impact of carbonates on the mineralisation of surface soil organic carbon in response to shift in tillage practice

The inorganic soil C pool is a major source of CO2 emission into the atmosphere along with the soil respiratory CO2 fluxes but is comparatively less studied than the organic C mineralisation processes. This study aims to understand how soil available carbonates influence the soil C dynamics under different tillage, mulching and temperature regimes. A 90-day incubation experiment was conducted by adding calcite nodules to soils (10% w/w) collected from an agricultural field maintained with or without 5 t ha−1 mulching under no-till (NT) or conventional tillage (CT) systems. Environmental Scanning Electron Microscope (ESEM) examination indicated greater morphological changes in the calcite nodules incubated with CT than NT soils. Soil samples incubated with calcite and mulching recorded 6.3% greater CO2 evolution than the un-mulched condition. Under the CT system, the overall CO2 emission rate was higher in the control treatment (43%), followed by a combined treatment of 5 t ha−1 mulch + CaCO3 (10% w/w) (29.2%), 5 t ha−1 mulch only treatment (27.9%), and 10% CaCO3 (w/w) (16.5%) treatment, with a rise in incubation temperature from 22 °C to 37 °C. Kinetic model calculations for CO2 emission indicated a greater half-life of easily mineralisable C pools in the NT system at 22 °C. Microbial biomass carbon (MBC) results further verified that the high temperature and disturbed soil conditions limit the availability of soil MBC under the CT systems, indicating a higher decomposition rate. Eventually, these results indicated that agricultural management practices, including tillage shift, explicitly influence the different functional components of soil organic matter (SOM)

Global emergency remote education in secondary schools during the COVID-19 pandemic: A systematic review

The worldwide shift to emergency remote education in 2020 as a result of the COVID-19 pandemic impacted billions of students and teachers. A range of teaching and learning strategies were employed by schools as a result, despite confusing and sometimes contradictory government guidance, with systemic issues such as equity and access impacting heavily on disadvantaged students. In light of the findings of a recent IPPO evidence snapshot and roundtable event, and in order to gain further insight into how emergency remote education was experienced by secondary school students, parents and educators, a systematic review was conducted that collates and synthesises primary empirical studies across five key research questions focusing on student engagement, online assessment, peer collaboration, parent engagement, and future directions for online learning. Studies were searched for in May 2021 using Web of Science, Scopus, ERIC, Microsoft Academic Graph, ResearchGate and the COVID-19 living map, and were included if they focused on teaching and learning using blended or online approaches in secondary schools during the pandemic, that were published in English. Following quality assessment on scope and methodological rigour, 81 studies were included for narrative synthesis. The research studies were conducted in 38 countries, with 37% of studies from low or lower-middle income countries, and 63% from upper-middle income or high-income countries. Most of the evidence came from students (64%), followed by teachers (53%), with very few studies exploring the perceptions and experiences of parents (6%) or school leaders (5%). Findings reveal that self-regulation and understanding were the most frequently reported indicators of student engagement, with online assessment tools, learning management systems with collaborative tools, live synchronous lessons with peer and teacher interaction, and teacher-made videos considered particularly engaging. Social isolation was the most frequently reported indicator of disengagement, characterised by poor attendance in live lessons, a lack of opportunities to seek help with challenges and difficulties facilitating peer collaboration. Although many articles reported that assessment online was particularly challenging, 21 different types of online assessments strategies were identified, with online quizzes and formative online feedback the most frequently used. Live marking or recorded feedback and assessment were found to be particularly beneficial, as providing feedback during live lessons was sometimes challenging. Peer collaboration was facilitated through peer assessment, inquiry-based group work and experiments, aided by the use of collaborative software and combining multiple applications. Parental involvement and support contributed to student learning, although issues of equity impacted the extent to which they could engage with their children's learning, alongside gaps in family content knowledge and technological skills. Numerous implications for future policy relating to online and blended learning are provided

At Our Own Peril: DoD Risk Assessment in a Post-Primacy World

The U.S. Department of Defense (DoD) faces persistent fundamental change in its strategic and operating environments. This report suggests this reality is the product of the United States entering or being in the midst of a new, more competitive, post-U.S. primacy environment. Post-primacy conditions promise far-reaching impacts on U.S. national security and defense strategy. Consequently, there is an urgent requirement for DoD to examine and adapt how it develops strategy and describes, identifies, assesses, and communicates corporate-level risk. This report takes on the latter risk challenge. It argues for a new post-primacy risk concept and its four governing principles of diversity, dynamism, persistent dialogue, and adaptation. The authors suggest that this approach is critical to maintaining U.S. military advantage into the future. Absent change in current risk convention, the report suggests DoD exposes current and future military performance to potential failure or gross under-performance.https://press.armywarcollege.edu/monographs/1410/thumbnail.jp

Biosolids application and soil organic carbon dynamics: a meta-analysis.

Soil carbon sequestration has been recognized as a potential “direct action” tool in mitigating climate change. Organic matter rich biosolids from wastewater industry has been applied to soils as one of the strategies to the carbon sequestration. However, most of the short- and long-term studies as influenced by land application of biosolids have been showed quite inconsistent results in carbon increments in soils. Therefore, soil carbon sequestration resulted by biosolids application is yet to be needed further studies to elucidate. This study presents a comprehensive MetaAnalysis (MA) on soil carbon sequestration as influenced by biosolids application. Datasets comprised with 175 independent paired-treatments across 25 countries were fed in to Comprehensive Meta-Analysis (version 3) programme and modelled. The MA compared Soil Organic Carbon (SOC as g/kg) changes as the functions of time after biosolids application and its rate over twelve groups under two categories: application age (time after application) as 11 year, and cumulative application rate as 251 tonnes/ha.The fixed model is applied to explicate overall effects of analysed data derived from the MA. The MA showed overall positive influences on soil carbon sequestration towards increasing SOC. For example, the highest effect on SOC was observed at 1-3 age group suggesting the need of short term biosolids application to develop carbon storage in soils. Overall, this study shows that land application of biosolids can be used to increase soil carbon storage and therefore has the potential to be a strategy for mitigating climate change towards carbon sequestration in soils

Assessment of the fertilizer potential of biochars produced from slow pyrolysis of biosolid and animal manures

Excessive amounts of animal manures and production of a large volume of biosolids pose serious environmental issues in terms of their safe disposal and management. Thermochemical treatment of bio-waste materials via pyrolysis can convert them into value-added products such as biochar-based fertilizers. In this study, fourteen biochars were produced from one biosolid and thirteen animal manures by slow pyrolysis at 300 °C. All feedstock and biochar samples were characterized by determining the yield, and physicochemical and surface properties, including the C-containing functional groups. Principal component and cluster analyses were used to classify the feedstock/biochar materials based on their mineral constituents. The biochar yield of various feedstocks ranged from 39 to 81%, with the highest yield for grain-fed cow manure. The highest N and K content was found in chicken manure biochar (57.8 and 29.2 g kg–1, respectively), while the highest P was found in biosolid biochar (40.5 g kg–1). The specific surface area of biochars ranged from 96.06–110.83 m2 g−1. Hierarchical analyses of the chemical compositions of feedstocks and biochars enabled grouping of the materials respectively into four and five distinguished clusters. Three principal components (PC) explained 86.8% and 83.3% of the variances in the feedstocks and biochars, respectively. The PC1 represented the content of the major nutrients (N, P and K), whereas PC2 and PC3 represented other nutrients (secondary and micronutrients) contents and physicochemical properties (pH and EC). The results of this study suggested that biochars produced from different manures and biosolids may potentially be a source of soil nutrients and trace elements. In addition, different biochars may be applied to different nutrient-deficient soils to avoid plausible nutrient and potentially toxic element contamination. © 2021 Elsevier B.V

Tetraspanin (TSP-17) Protects Dopaminergic Neurons against 6-OHDA-Induced Neurodegeneration in <i>C. elegans</i>

Parkinson's disease (PD), the second most prevalent neurodegenerative disease after Alzheimer's disease, is linked to the gradual loss of dopaminergic neurons in the substantia nigra. Disease loci causing hereditary forms of PD are known, but most cases are attributable to a combination of genetic and environmental risk factors. Increased incidence of PD is associated with rural living and pesticide exposure, and dopaminergic neurodegeneration can be triggered by neurotoxins such as 6-hydroxydopamine (6-OHDA). In C. elegans, this drug is taken up by the presynaptic dopamine reuptake transporter (DAT-1) and causes selective death of the eight dopaminergic neurons of the adult hermaphrodite. Using a forward genetic approach to find genes that protect against 6-OHDA-mediated neurodegeneration, we identified tsp-17, which encodes a member of the tetraspanin family of membrane proteins. We show that TSP-17 is expressed in dopaminergic neurons and provide genetic, pharmacological and biochemical evidence that it inhibits DAT-1, thus leading to increased 6-OHDA uptake in tsp-17 loss-of-function mutants. TSP-17 also protects against toxicity conferred by excessive intracellular dopamine. We provide genetic and biochemical evidence that TSP-17 acts partly via the DOP-2 dopamine receptor to negatively regulate DAT-1. tsp-17 mutants also have subtle behavioral phenotypes, some of which are conferred by aberrant dopamine signaling. Incubating mutant worms in liquid medium leads to swimming-induced paralysis. In the L1 larval stage, this phenotype is linked to lethality and cannot be rescued by a dop-3 null mutant. In contrast, mild paralysis occurring in the L4 larval stage is suppressed by dop-3, suggesting defects in dopaminergic signaling. In summary, we show that TSP-17 protects against neurodegeneration and has a role in modulating behaviors linked to dopamine signaling

Boron contamination and its risk management in terrestrial and aquatic environmental settings

Boron (B) is released to terrestrial and aquatic environments through both natural and anthropogenic sources. This review describes the current knowledge on B contamination in soil and aquatic environments in relation to its geogenic and anthropogenic sources, biogeochemistry, environmental and human health impacts, remediation approaches, and regulatory practices. The common naturally occurring sources of B include borosilicate minerals, volcanic eruptions, geothermal and groundwater streams, and marine water. Boron is extensively used to manufacture fiberglass, thermal-resistant borosilicate glass and porcelain, cleaning detergents, vitreous enamels, weedicides, fertilizers, and B-based steel for nuclear shields. Anthropogenic sources of B released into the environment include wastewater for irrigation, B fertilizer application, and waste from mining and processing industries. Boron is an essential element for plant nutrition and is taken up mainly as boric acid molecules. Although B deficiency in agricultural soils has been observed, B toxicity can inhibit plant growth in soils under arid and semiarid regions

Retrieving back plastic wastes for conversion to value added petrochemicals: opportunities, challenges and outlooks

Plastic production and its unplanned management and disposal, has been shown to pollute terrestrial, aquatic, and atmospheric environments. Petroleum-derived plastics do not decompose and tend to persist in the surrounding environment for longer time. Plastics can be ingested and accumulate into the tissues of both terrestrial and aquatic animals, which can impede their growth and development. Petrochemicals are the primary feedstocks for the manufacture of plastics. The plastic wastes can be retrieved back for conversion to value added petrochemicals including aromatic char, hydrogen, synthesis gas, and bio-crude oil using various technologies including thermochemical, catalytic conversion and chemolysis. This review focusses on technologies, opportunities, challenges and outlooks of retrieving back plastic wastes for conversion to value added petrochemicals. The review also explores both the technical and management approaches for conversion of plastic wastes to petrochemicals in regard to commercial feasibility, and economic and environmental sustainability. Further, this review work provides a detailed discussion on opportunities and challenges associated with recent thermochemical and catalytic conversion technologies adopted for retrieving plastic waste to fuels and chemicals. The review also recommends prospects for future research to improve the processes and cost-efficiency of promising technologies for conversion of plastic wastes to petrochemicals. It is envisioned that this review would overcomes the knowledge gaps on conversion technologies and further contribute in emerging sustainable approaches for exploiting plastic wastes for value-added products