21,886 research outputs found

    Chemical sulfatization of chrome-containing sludges from DUBERSAY tailing dump

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    Waste chromium production sludge from the Dubersay tailings dump is present in huge quantities with a magnesium oxide content of up to 40 %. The chrome-containing waste was sintered at 1 100 ¬įC, the resulting sinter was mixed with sulphuric acid when heated to 300 ¬įC. The resulting mixture after heating was leached with water at 90 ¬įC, the solid precipitate was washed and dried to yield a chrome concentrate containing 55,4 % Cr2O3, 8,2 % SiO2. Evaporation of the purified solution produces magnesium sulphate which is a magnesium fertilizer

    Composting of distillery spent wash

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    Distillery spent wash, a by-product of the alcoholic beverage industry, is an organic waste whose management poses significant challenges due to its acidity, high organic load, notable content of polyphenols, macronutrients, micronutrients and heavy metals. In Europe, billions of liters of distillery waste are generated annually and its eco-unfriendly disposal can cause severe environmental and health impacts. Composting is a viable management strategy to treat and manage distillery slop promoting the recycling and stabilization of organic matter and nutrients in the material. The review examines different composting methods, such as single composting, co-composting and vermicomposting, along with their benefits and drawbacks. To optimize composting effectiveness, various materials, such as sewage sludge, vinasse, green and animal manure, inorganic amendments, bagasse, filter cake and municipal solid waste, among other agro-food and animal bio-wastes, can be used as a source of nitrogen and microorganisms. Also, the usage of different materials and mixtures aims to enhance the composting process increasing the degradation rate and the quality of the compost. The challenges of distillery spent wash composting are also covered in the paper which are mainly due to its characteristics, including high salt content, low carbon-to-nitrogen ratio, low pH and potential phytotoxicity. The paper concludes that composting distillery spent wash is an effective and sustainable waste management solution for recovering valuable nutrient resources and producing a stable nutrient-rich organic soil amendment. The produced compost can improve crop yields, nutrient absorption by plants and plant biomass and contribute to soil properties and restoration. The review provides insights into the current state of distillery spent wash composting and recommends future research directions to improve efficiency and expand potential applications

    Suitability of 210Pbex, 137Cs and 239+240Pu as soil erosion tracers in western Kenya

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    Land degradation resulting from soil erosion is a global concern, with the greatest risk in developing countries where food and land resources can be limited. The use of fallout radionuclides (FRNs) is a proven method for determining short and medium-term rates of soil erosion, to help improve our understanding of soil erosion processes. There has been limited use of these methods in tropical Africa due to the analytical challenges associated with 137Cs, where inventories are an order of magnitude lower than in the Europe. This research aimed to demonstrate the usability of 239+240Pu as a soil erosion tracer in western Kenya compared to conventional isotopes 210Pbex and 137Cs through the determination of FRN depth profiles at reference sites. Across six reference sites 239+240Pu showed the greatest potential, with the lowest coefficient of variation and the greatest peak-to-detection limit ratio of 640 compared to 5 and 1 for 210Pbex and 137Cs respectively. Additionally, 239+240Pu was the only radionuclide to meet the ‚Äėallowable error‚Äô threshold, demonstrating applicability to large scale studies in Western Kenya where the selection of suitable reference sites presents a significant challenge. The depth profile of 239+240Pu followed a polynomial function, with the maximum areal activities found between depths 3 and 12 cm, where thereafter areal activities decreased exponentially. As a result, 239+240Pu is presented as a robust tracer to evaluate soil erosion patterns and amounts in western Kenya, providing a powerful tool to inform and validate mitigation strategies with improved understanding of land degradation

    Chemical sulfatization of chrome-containing sludges from DUBERSAY tailing dump

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    Waste chromium production sludge from the Dubersay tailings dump is present in huge quantities with a magnesium oxide content of up to 40 %. The chrome-containing waste was sintered at 1 100 ¬įC, the resulting sinter was mixed with sulphuric acid when heated to 300 ¬įC. The resulting mixture after heating was leached with water at 90 ¬įC, the solid precipitate was washed and dried to yield a chrome concentrate containing 55,4 % Cr2O3, 8,2 % SiO2. Evaporation of the purified solution produces magnesium sulphate which is a magnesium fertilizer

    Insights into mode of action mediated responses following pharmaceutical uptake and accumulation in plants

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    The reuse of wastewater to meet irrigation requirements and slurries, sludges and manures as fertilisers to meet crop nutrient demands inadvertently introduces human and veterinary-use pharmaceuticals into the agro-ecosystem. This review synthesises recent research, which has observed sub-lethal effects, following pharmaceutical uptake by plants. Potential links between pharmaceutical mode of action and observed sub-lethal effects in the plant were then examined. Common receptors and biological pathways across species suggests a clear need to integrate plant cellular biology into our understanding of the impacts of pharmaceuticals on important plant functions and processes. To help prioritise future research efforts an analysis of shared mammalian and plant biochemical pathways was undertaken to identify classes of pharmaceuticals which may present a greater risk to key plant functions. These included sulfonylurea antihyperglycemics, steroids, opiods, antipsychotic phenothiazines and pharmaceuticals targeting several neurotransmitters shared between mammals and plants (including beta-blockers, antihistamines and benzodiazepines). Whilst a number of pharmaceutical induced sub-lethal effects have been observed, this review highlights the clear need to study a wider range of pharmaceuticals on a broader range of plant species, including cover crops and wild plants, under realistic exposure scenarios, to fully understand the wider implications of pharmaceutical exposure in agro-ecosystems. State-of-the art omics-techniques offer great potential to understand the mode of action of pharmaceuticals in plants and elucidate links between the pharmaceutical intended mode of action and observed plant effects. In addition, studies under co-stress from pharmaceutical exposure and other stressors such as increased temperatures, drought or pests are lacking and present an urgent research need in the face of feeding a growing population under the threats of climate change

    Utilization of wastewater treatment sludge in the production of fired clay bricks: An approach towards sustainable development

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    Wastewater treatment sludge has increase due to the increasing of population and economic potential. Sludge generally contains heavy metals that could lead to environmental effect as well as to human health. This study is focus on utilization of sludges into incorporated fired clay brick. The samples of sludge were gathered from IWK in Perwira and Senggarang. The heavy metal concentration in the wastewater treatment sludge was identified using X-Ray Fluorescence. Sludges were incorporated into bricks at various percentages: 0 %, 1 %, 5 %, 10 %, 20 %, and 30 %. The physical and mechanical characteristics of brick after being integrated with both types of sludges were identified. Furthermore, heavy metals leachability of sludge bricks was tested. The findings reveal that Barium (Ba) has the highest heavy metal concentration in the raw materials, and the chemical composition is Silicon Dioxide (SiO2). Bricks with 5 % sludge content exhibited optimal physical and mechanical attributes for both sludge types. However, sludge from Senggarang exhibited the better results compared to Perwira sludge. In terms of leachability, heavy metals were analysed in bricks from both sludge types. Bricks containing up to 20 % sludge from Senggarang exhibited the lowest heavy metal leachability. Nevertheless, value of heavy metals from both sludges is complied with USEPA standard. In conclusion, 5 % of both sludges is the best percentage to be utilized into fired clay brick by considering it properties and leachability. This study also demonstrated that adopting cleaner production techniques for building bricks can make a substantial contribution towards attaining Sustainable Development Goals (SDGs)

    Stabilization of metal and metalloids from contaminated soils using magnesia-based tundish deskulling waste from continuous steel casting

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    This study presents a groundbreaking exploration into the potential use of refractory tundish deskulling waste (TUN), a magnesium oxide-based by-product from continuous steel casting, as a stabilizing agent for remediating metal and metalloids contaminated soils. Up-flow column horizontal percolation tests were conducted to measure the concentrations of metals and metalloids, pH, and electrical conductivity (EC) in the leachates of two different combinations of contaminated soil and stabilizer (95-5 wt% and 90-10 wt%). The effectiveness of TUN as a soil-stabilizing agent for contaminated soils with metals and metalloids was evaluated by comparing its leachates with those obtained from a sample of a well-established low-grade magnesium oxide (LG-MgO) by-product, which underwent the same testing procedure. The findings revealed a significant correlation between the mobility of the examined metals and metalloids, and the water-soluble or acid phase of the contaminated soil, primarily governed by precipitation-solution reactions. While the stabilizing impact on non-pH-dependent metals, particularly redox-sensitive oxyanions, was less pronounced, both MgO-based stabilizers exhibited a favourable influence on soil pH-dependent metals and metalloids. They achieved this by establishing an optimal pH range of approximately 9.0-10.5, wherein the solubility of metal (hydr)oxides is minimized. Notably, metals like Zn and Cu, which have high leaching potential, experienced a remarkable reduction in leaching - Zn by over 99% and Cu by around 97% - regardless of the stabilizer content. In a broader context, this research champions the principles of the circular economy by offering a technical remedy for treating soils contaminated with pH-dependent metals and metalloids. The proposed solution harnesses industrial waste - currently relegated to landfills - as a resource, aligning with sustainable practices and environmental responsibility

    Hanford Low-Activity Waste Vitrification: A Review

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    This Paper Summarizes the Vast Body of Literature (Over 200 Documents) Related to Vitrification of the Low-Activity Waste (LAW) Fraction of the Hanford Tank Wastes. Details Are Provided on the Origins of the Hanford Tank Wastes that Resulted from Nuclear Operations Conducted between 1944 and 1989 to Support Nuclear Weapons Production. Waste Treatment Processes Are Described, Including the Baseline Process to Separate the Tank Waste into LAW and High-Level Waste Fractions, and the LAW Vitrification Facility Being Started at Hanford. Significant Focus is Placed on the Glass Composition Development and the Property-Composition Relationships for Hanford LAW Glasses. Glass Disposal Plans and Criteria for Minimizing Long-Term Environmental Impacts Are Discussed Along with Research Perspectives

    Enzyme activities in vineyard soils long-term treated with copper-based fungicides

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    Copper-based fungicides have been applied in vineyard soils for a long time, which has resulted in increasing soil Cu concentration. However, information relating to non-target effects of these fungicides on microorganisms of these soils is scarce. The aim of this study was to determine the potential enzyme activities of vineyard soils in relation to Cu content and evaluate the potential risks of long-term application of Cu-based fungicides. For this purpose, a wide range of soil samples, having different total, exchangeable and bioavailable Cu contents, were collected from six regions of quality wines located in the NW Iberian Peninsula, and the activity of dehydrogenase, b-glucosidase, urease and phosphatase were measured. Overall, the results obtained indicate adverse effects of Cu on dehydrogenase, b-glucosidase and phosphatase activities and an inconsistent effect on urease activity. Threshold Cu concentrations at which changes in the enzyme activities became evident were 150e200 mg total Cu kg 1 and 60e80 mg bioavailable Cu kg-1.Xunta de Galici

    Potencial biotecnol√≥gico de Pedobacter lusitanus NL19 uma nova esp√©cie isolada de lamas de uma mina de ur√Ęnio em Portugal

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    Bioactive natural products (BNPs) play an important role in our daily lives, especially as therapeutic agents. One example is antibiotics, which have been widely used in human health. The inappropriate use of these antibiotics has led to an increase in bacterial resistance, which is a problem of worldwide concern, warning for the urgent need for new effective alternatives. Extreme environments have already proven to be a rich source of microorganisms producing new chemical entities with important biological properties, namely antimicrobials. In the present study one such environment was explored. We have isolated several bacteria from sludges contaminated with radionuclides and metals, collected from a uranium mine run-off in Quinta do Bispo, Viseu, Portugal. One strain was selected based on its broad activity against Grampositive and Gram-negative bacteria, and also yeasts, with relevance in the clinical, food, veterinary and aquaculture settings. The phylogenetic analysis of the 16S rRNA, gyrB and Internal Transcribed Spacer (ITS) gene sequences identified this strain as belonging to the genus Pedobacter, and having P. himalayensis, P. cryoconitis, P. westerhofensis and P. hartonius as closely related species. Further polyphasic analysis showed that the strain is a new bacterial species, and which was named Pedobacter lusitanus NL19. In silico analysis of NL19 genome sequence revealed the presence of 17 biosynthetic gene clusters (BGCs) for different classes of BNPs, including nonribosomal peptide (NRPs), polyketides (PKs), ribosomally synthesized and posttranslationally modified peptides (RiPPs), siderophores, terpenes and several hybrid NRPs-PKs. NL19 bioactivity was detected in solid medium but not in its equivalent broth. Further investigations showed that a high concentration of peptone from casein (PC) was the main factor associated with the lack of bioactivity by NL19 in broth. On the contrary, in broth with a low concentration of PC, the compounds produced by NL19 showed a broad spectrum of activity against bacteria and yeasts. Furthermore, the bioactivity detected was mainly due to the presence of pedopeptins, which are NRPs and whose genes are present in the NL19 genome. These results were supported by RNA-seq and validated by qPCR, which showed that the transcription of pedo_nrps genes was significantly downregulated in cells grown in a high concentration of PC. Also, NL19¬ī RNA-seq transcriptome data in high and low PC concentrations, allowed us to identify 261 differentially expressed genes (DEGs). In general, at high concentrations of PC, in addition to the genes involved in pedopeptins biosynthesis, genes involved in the de novo biosynthesis of biotin were also found to be significantly downregulated. In this condition genes that encode putative efflux pumps as well as ferrous iron capture system, were significantly upregulated, which suggests redirection of cellular metabolism. Genome mining approaches also revealed that NL19 and its closely related species have an important collection of new NRPS-BGCs. Finally, the pan-genome analyses highlight the genus Pedobacter as a prolific source of relevant new BNPs including NRPs, PKs, RiPPs, hidroxamate, carotenoids and squalene, mainly the NL19 and P. cryoconitis species. The work developed reinforces the relevance of bioprospecting extreme environments. The characterization of the strain P. lusitanus NL19 reveals the enormous, yet still untapped, biotechnological potential of this strain, and also of other members of the genus Pedobacter, for the discovery of new compounds with diverse biotechnological applications, including therapeutic ones.Os produtos naturais bioativos (BNPs) t√™m um grande impacto no nosso quotidiano, principalmente como agentes terap√™uticos. Um exemplo s√£o os antibi√≥ticos, que t√™m sido amplamente usados na melhoria da sa√ļde humana. O uso inadequado destes antibi√≥ticos tem levado ao crescente aumento de resist√™ncia bacteriana, sendo esta uma preocupa√ß√£o mundial que obriga a explorar novas alternativas eficazes. Os ambientes extremos t√™m mostrado ser uma rica fonte de microrganismos produtores de novas entidades qu√≠micas, com importantes propriedades biol√≥gicas, nomeadamente, antimicrobianas. No presente estudo explor√°mos um desses ambientes. Isol√°mos v√°rias bact√©rias a partir de lamas contaminadas com radionucl√≠deos e metais, que foram recolhidas na mina de ur√Ęnio desativada na Quinta do Bispo, Viseu-Portugal. Um isolado bacteriano foi selecionado por apresentar amplo espetro de atividade contra bact√©rias de Gram-positivo, de Gram-negativo, e tamb√©m leveduras, com relev√Ęncia nas √°reas cl√≠nica, alimentar, veterin√°ria e aquacultura. Esse isolado foi identificado e caracterizado por an√°lises filogen√©ticas das sequ√™ncias dos genes 16S rRNA, gyrB e de espa√ßadores do transcrito interno (ITSs), como pertencendo ao g√©nero Pedobacter e tendo como esp√©cies pr√≥ximas P. himalayensis, P. cryoconitis, P. westerhofensis e P. hartonius. A an√°lise polif√°sica revelou ser uma nova esp√©cie bacteriana a que se deu o nome Pedobacter lusitanus NL19. A an√°lise in silico do seu genoma revelou a presen√ßa de 17 agrupamentos de genes biossint√©ticos (BGCs) para diferentes classes de BNPs, incluindo p√©ptidos n√£o ribossomais (NRPs), polic√©tidos (PKs), p√©ptidos ribossomais p√≥s-traducionalmente modificados (RiPPs), sider√≥foros, terpenos e v√°rios NRPs-PKs h√≠bridos. A bioatividade da NL19 foi detectada quando a bact√©ria foi cultivada em meio s√≥lido, mas n√£o no meio l√≠quido equivalente. Verific√°mos ainda que elevadas concentra√ß√Ķes de peptona de case√≠na (PC) afectam a bioatividade da NL19 quando cultivada em meio l√≠quido e que os compostos produzidos a baixas concentra√ß√Ķes de PC t√™m atividade contra bact√©rias e leveduras. A bioatividade detectada foi associada √† presen√ßa das pedopeptinas, que s√£o NRPs e cujos genes est√£o presentes no genoma da NL19. Estes dados foram suportados pelos resultados da an√°lise por RNA-seq e validados por qPCR, que mostram que os genes pedo_nrps se encontram significativamente subexpressos em c√©lulas cultivadas em elevadas concentra√ß√Ķes de PC. Para al√©m disso, os dados obtidos da an√°lise do transcriptoma da NL19 cultivada em elevadas e baixas concentra√ß√Ķes de PC, permitiram identificar 261 genes diferencialmente expressos (DEGs). De uma forma geral, em concentra√ß√Ķes elevadas de PC, para al√©m dos genes envolvidos na bioss√≠ntese das pedopeptinas, tamb√©m os genes envolvidos na bioss√≠ntese de novo da biotina se encontravam significativamente subexpressos. Nesta condi√ß√£o, os genes codificantes para bombas de efluxo, bem como para um sistema de captura de ferro ferroso, estavam significativamente sobreexpressos, sugerindo um redirecionamento do metabolismo celular. A minera√ß√£o do genoma revelou ainda que a NL19 e as esp√©cies pr√≥ximas atr√°s referidas, possuem uma importante cole√ß√£o de novos NRPS-BGCs. Finalmente, a an√°lise dos pangenomas revelaram que o g√™nero Pedobacter, nomeadamente, as esp√©cies NL19 e P. cryoconitis, √© fonte prol√≠fica de novas classes de BNPs, incluindo NRPs, PKs, RiPPs, hidroxamato, caroten√≥ides e esqualeno. Os resultados obtidos ao longo deste trabalho refor√ßam a relev√Ęncia da bioprospec√ß√£o dos ambientes extremos. Para al√©m disso, a caracteriza√ß√£o da estirpe P. lusitanus NL19, e de outras esp√©cies pr√≥ximas, revela o enorme, mas ainda inexplorado, potencial biotecnol√≥gico desta estirpe, bem como de membros do g√©nero Pedobacter, para a descoberta de novos compostos com diversas aplica√ß√Ķes biotecnol√≥gicas, inclusive terap√™uticas.Programa Doutoral em Biologi
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