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Trace metals in polyethylene debris from the North Atlantic subtropical gyre 全文
2019
Prunier, Jonathan | Maurice, Laurence | Perez, Emile | Gigault, Julien | Pierson Wickmann, Anne-Catherine | Davranche, Mélanie | Halle, Alexandra ter
Plastic pollution in the marine environment poses threats to wildlife and habitats through varied mechanisms, among which are the transport and transfer to the food web of hazardous substances. Still, very little is known about the metal content of plastic debris and about sorption/desorption processes, especially with respect to weathering. In this study, plastic debris collected from the North Atlantic subtropical gyre was analyzed for trace metals; as a comparison, new packaging materials were also analyzed. Both the new items and plastic debris showed very scattered concentrations. The new items contained significant amounts of trace metals introduced as additives, but globally, metal concentrations were higher in the plastic debris. The results provide evidence that enhanced metal concentrations increase with the plastic state of oxidation for some elements, such as As, Ti, Ni, and Cd. Transmission electron microscopy showed the presence of mineral particles on the surface of the plastic debris. This work demonstrates that marine plastic debris carries complex mixtures of heavy metals. Such materials not only behave as a source of metals resulting from intrinsic plastic additives but also are able to concentrate metals from ocean water as mineral nanoparticles or adsorbed species.
显示更多 [+] 显示较少 [-]Biofiltration of methane using hybrid mixtures of biochar, lava rock and compost 全文
2018
La, Helen | Hettiaratchi, J. Patrick A. | Achari, Gopal | Verbeke, Tobin J. | Dunfield, Peter F.
Using hybrid packing materials in biofiltration systems takes advantage of both the inorganic and organic properties offered by the medium including structural stability and a source of available nutrients, respectively. In this study, hybrid mixtures of compost with either lava rock or biochar in four different mixture ratios were compared against 100% compost in a methane biofilter with active aeration at two ports along the height of the biofilter. Biochar outperformed lava rock as a packing material by providing the added benefit of participating in sorption reactions with CH4. This study provides evidence that a 7:1 volumetric mixture of biochar and compost can successfully remove up to 877 g CH4/m3·d with empty-bed residence times of 82.8 min. Low-affinity methanotrophs were responsible for the CH4 removal in these systems (KM(app) ranging from 5.7 to 42.7 µM CH4). Sequencing of 16S rRNA gene amplicons indicated that Gammaproteobacteria methanotrophs, especially members of the genus Methylobacter, were responsible for most of the CH4 removal. However, as the compost medium was replaced with more inert medium, there was a decline in CH4 removal efficiency coinciding with an increased dominance of Alphaproteobacteria methanotrophs like Methylocystis and Methylocella. As a biologically-active material, compost served as the sole source of nutrients and inoculum for the biofilters which greatly simplified the operation of the system. Higher elimination capacities may be possible with higher compost content such as a 1:1 ratio of either biochar or lava rock, while maintaining the empty-bed residence time at 82.8 min.
显示更多 [+] 显示较少 [-]First data on plastic ingestion by blue sharks (Prionace glauca) from the Ligurian Sea (North-Western Mediterranean Sea) 全文
2018
Bernardini, Ilaria | Garibaldi, Fulvio | Canesi, Laura | Fossi, Maria Cristina | Baini, Matteo
Few studies have focused so far on plastic ingestion by sharks in the Mediterranean Sea. The aim of this paper was to determine, for the first time, the plastic litter ingested by blue sharks (Prionace glauca), categorized as “Critically Endangered” in the Mediterranean Sea by IUCN, caught in the Pelagos Sanctuary SPAMI (North-Western Mediterranean Sea). The analysis of the stomach contents was performed following the MSFD Descriptor 10 standard protocol implemented with FT-IR spectroscopy technique. The results showed that 25.26% of sharks ingested plastic debris of wide scale of sizes from microplastics (<5 mm) to macroplastics (>25 mm). The polyethylene sheetlike user plastics, widely used as packaging material, are the most ingested debris. This research raises a warning alarm on the impact of plastic debris on a threatened species, with a key role in the food web, and adds important information for futures mitigation actions.
显示更多 [+] 显示较少 [-]Large amounts of marine debris found in sperm whales stranded along the North Sea coast in early 2016 全文
2016
Unger, Bianca | Rebolledo, Elisa L Bravo | Deaville, Rob | Gröne, Andrea | IJsseldijk, Lonneke L. | Leopold, Mardik F. | Siebert, Ursula | Spitz, Jérôme | Wohlsein, Peter | Herr, Helena
30 sperm whales (Physeter macrocephalus) stranded along the coasts of the North Sea between January and February 2016. The gastro-intestinal tracts of 22 of the carcasses were investigated. Marine debris including netting, ropes, foils, packaging material and a part of a car were found in nine of the 22 individuals. Here we provide details about the findings and consequences for the animals. While none of the items was responsible for the death of the animal, the findings demonstrate the high level of exposure to marine debris and associated risks for large predators, such as the sperm whale.
显示更多 [+] 显示较少 [-]Swine Wastewater Treatment for Small Farms by a New Anaerobic-Aerobic Biofiltration Technology 全文
2019
Escalante-Estrada, V. E. | Garzón-Zúñiga, M. A. | Valle-Cervantes, S. | Páez-Lerma, J. B.
Effluents form the swine livestock industry contain a high concentration of pollutants and require complex treatment systems. The most recurrent form to treat Swine wastewater is by a conventional anaerobic–aerobic treatment. For example, an up-flow anaerobic blanket sludge reactor followed by an activated sludge reactor. However, in many countries, a high percentage of producers are small or medium-sized farms that can afford neither complex treatment systems nor specialized operations. The present study assessed the performance of a novel and different combinations of treatment processes, based on changing the anaerobic systems that require a specialized operation for one very simple to operate for farm owners. The assessed system is composed by a septic tank in combination with an up-flow anaerobic filter packed with volcanic rocks and an aerobic biofilter packed with waste wood chips. The effect of the hydraulic residence time and the volumetric organic loading in the septic tank and up-flow anaerobic filter and the effect of surface hydraulic loading in the aerobic biofilter were also evaluated. The system efficiently removed chemical oxygen demand (86–93%), total suspended solids (91–97%), volatile suspended solids (86–97%), and ammoniacal nitrogen (86–87%), showing a constant removal efficiency under a VOL of between 5 and 14.6 kg COD m⁻³ d⁻¹in the up-flow anaerobic filter. The advantages of this system are that the packing materials can be available in rural zones and are sustainable; the whole system is cost-effective and easy to handle; thus, farmers can operate and maintain it with their own means.
显示更多 [+] 显示较少 [-]Integral Approach for Improving the Degradation of Recalcitrant Petrohydrocarbons in a Fixed-Film Reactor 全文
2011
Jiménez, Verónica | Bravo, Violeta | Gutierrez, Linda Gonzalez
The degradation of diesel and phenanthrene in waste water was studied in a column combining a submerged trickling-flow with a fixed-film at a determined biofilm thickness with recirculation. Degradation efficiencies were found to be high with the production of a biofilm thickness of 789 μm structured in a package material with proper adsorption and physicochemical properties necessary to reach a stable state condition for the degradation of recalcitrant components in 78% at a retention time of 3 h. Improved degradation rates were reached with a biofilm built from an adapted inoculum that showed the presence of Pseudomonas sp., Klebsiella sp. Enterobacter in a concentration of 6.45â×â109 CFU mL−1. Moreover, the biodegradation rate of the inoculumn was quantified. The diesel kinetic experimental data were well described by Gompertz model which provides a specific grow rate (Kb) of 0.76â±â0.36 h−1 and a correlation of R 2â=â0.93. The integral approach study of the variables of a complex degradation process lead to improve the complete operation of the reactor in comparison with other more specific component-based approaches.
显示更多 [+] 显示较少 [-]Firefighting of subsurface coal fires with comprehensive techniques for detection and control: a case study of the Fukang coal fire in the Xinjiang region of China 全文
2019
Tan, Bo | Zhang, Feichao | Zhang, Qingsong | Wei, Hongyi | Shao, Zhuangzhuang
Coal fires are global disasters, and China suffers the most serious coal fire disasters in the world. This paper introduces detailed detection and extinguishing methods for the wide range and complex coal fires at the No. 1 well in the Fukang mining area. First, the characteristics of the large and complex coal fire areas in the No. 1 well in the Fukang mining area are introduced, and 5 large fire areas are detected using the comprehensive detection range method, which detects fire areas before fire engineering practices are implemented. From the characteristics of this large-scale, complex coal fire, the zonal fire extinguishing scheme is formulated, designed, and applied, and the “shallow open fire stripping—construction of the boundary isolation zone—drilling and grouting in the deep fire area” series of events is utilized in the zonal fire extinguishing scheme. A new type of sodium silicate gel in compressive moisturizing plastic packing materials is used, an automatic grouting system is developed, and effective grouting processes are proposed, which can be adjusted according to the grouting effect analysis of the grouting parameters to determine the natural sedimentation and diffusion radius. After the construction was completed, the fire extinguishing effect was tested, revealing that the temperature in the fire zone cooled in a short time, and no subsequent heating phenomenon occurs. The method proposed in this paper provides guidance and a reference for other coal fires in the world.
显示更多 [+] 显示较少 [-]Endocrine disruption as an adverse effect of non-endocrine targeting pharmaceuticals 全文
2019
Sabir, Shakila | Akhtar, Muhammad Furqan | Saleem, Ammara
Endocrine disruptors have gained widespread attention owing to their severe adverse health impacts. These produce enormous burden of disease and are associated with high economic cost especially in developed countries. Environmental pollutants causing endocrine disruption include pesticides, industrial wastes, packaging materials, food constituents, plastics, and cosmetic products. Likewise, pharmaceutical drugs have the endocrine disrupting potential through a wide array of mechanisms. Antipsychotic, antiepileptic, antihypertensive, antiviral, antidiabetic, and anticancer drugs are among the foremost non-hormonal endocrine disruptors. Several drugs affect thyroid hormone synthesis via interaction with iodine uptake to the release of T3 and T4 by thyrocytes. Prolonged use of some drugs increase susceptibility to diabetes mellitus either by direct destruction of β cells or enhanced insulin resistance. Other drugs may cause serious developmental defects in male or female reproductive system. Appropriate understanding of the mechanisms of endocrine disruption associated with non-hormonal drugs will guide future drug development and help us prevent and cure endocrine-related toxicity of pharmaceuticals. Therefore, this review focuses on endocrine disruption by pharmaceutical drugs as their side effect.
显示更多 [+] 显示较少 [-]Biofilter with mixture of pine bark and expanded clay as packing material for methane treatment in lab-scale experiment and field-scale implementation 全文
2018
Liu, Fang | Wienke, Cindy | Fiencke, Claudia | Guo, Jianbin | Dong, Renjie | Pfeiffer, Eva-Maria
Low methane (CH₄) emission reduction efficiency (< 25%) has been prevalent due to inefficient biological exhaust gas treatment facilities in mechanic biological waste treatment plants (MBTs) in Germany. This study aimed to quantify the improved capacity of biofilters composed of a mixture of organic (pine bark) and inorganic (expanded clay) packing materials in reducing CH₄ emissions in both a lab-scale experiment and field-scale implementation. CH₄ removal performance was evaluated using lab-scale biofilter columns under varied inflow CH₄ concentrations (70, 130, and 200 g m⁻³) and corresponding loading rates of 8.2, 4.76, and 3.81 g m⁻³ h⁻¹, respectively. The laboratory CH₄ removal rates (1.2–2.2 g m⁻³ h⁻¹) showed positive correlation with the inflow CH₄ loading rates (4–8.2 g m⁻³ h⁻¹), indicating high potential for field-scale implementation. Three field-scale biofilter systems with the proposed mixture packing materials were constructed in an MBT in Neumünster, northern Germany. A relatively stable CH₄ removal efficiency of 38–50% was observed under varied inflow CH₄ concentrations of 28–39 g m⁻³ (loading rates of 1120–2340 g m⁻³ h⁻¹) over a 24-h period. The CH₄ removal rate was approximately 500–700 g m⁻³ h⁻¹, which was significantly higher than relevant previously reported field-scale biofilter systems (16–50 g m⁻³ h⁻¹). The present study provides a promising configuration of biofilter systems composed of a mixture of organic (pine bark) and inorganic (expanded clay) packing materials to achieve high CH₄ emission reduction. Graphic abstract ᅟ
显示更多 [+] 显示较少 [-]Oxidation of methane in biotrickling filters inoculated with methanotrophic bacteria 全文
2017
Cáceres Sánchez, Manuel | Dorado, Antonio D. | Gentina, Juan C. | Aroca, Germán
The oxidation of methane (CH₄) using biofilters has been proposed as an alternative to mitigate anthropogenic greenhouse gas emissions with a low concentration of CH₄ that cannot be used as a source of energy. However, conventional biofilters utilize organic packing materials that have a short lifespan, clogging problems, and are commonly inoculated with non-specific microorganisms leading to unpredictable CH₄ elimination capacities (EC) and removal efficiencies (RE). The main objective of this work was to characterize the oxidation of CH₄ in two biotrickling filters (BTFs) packed with polyethylene rings and inoculated with two methanotrophic bacteria, Methylomicrobium album and Methylocystis sp., in order to determine EC and CO₂ production (pCO₂) when using a specific inoculum. The repeatability of the results in both BTFs was determined when they operated at the same inlet load of CH₄. A dynamic mathematical model that describes the CH₄ abatement in the BTFs was developed and validated using mass transfer and kinetic parameters estimated independently. The results showed that EC and pCO₂ of the BTFs are not identical but very similar for all the conditions tested. The use of specific inoculum has shown a faster startup and higher EC per unit area (0.019 gCH₄ m⁻² h⁻¹) in comparison to most of the previous studies at the same CH₄ load rate (23.2 gCH₄ m⁻³ h⁻¹). Global mass balance showed that the maximum reduction of CO₂ equivalents was 98.5 gCO₂ₑq m⁻³ h⁻¹. The developed model satisfactorily described CH₄ abatement in BTFs for a wide range of conditions.
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