574 research outputs found

    Techno Economic Analysis of Interconnected Digital Home Networks

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    A home network is a popular method of allowing computers to communicate with each other within a given residential area or a local area network. Homes are the new frontiers of technology in the current global scenario, a digital interconnected home network is a reality and an efficient means to exchange information seamlessly across different homes and across different geographies is the need of the hour. The interconnection of different homes is possible with the existing ADSL subscriptions but would need changes in the existing gateway structures, which could be challenging for the less techno-savvy. In an effort to make life easier for the end user and help making the interconnection between various home networks seamless, a small device called I-Box is introduced through this project, which is essentially a small UPnP device with rich features and functionalities. This thesis gives an overview of the I-Box technology and with the help of various popular theoretical frameworks and concepts, investigates available Marketing channels and suggests a suitable deployment strategy for the I-Box by making a comparative study of the various possible scenarios and thereby identifying the most suitable model for its deployment

    Treatment of phenanthrene and benzene using microbial fuel cells operated continuously for possible in situ and ex situ applications

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    Bioelectrochemical systems could have potential for bioremediation of contaminants either in situ or ex situ. The treatment of a mixture of phenanthrene and benzene using two different tubular microbial fuel cells (MFCs) designed for either in situ and ex situ applications in aqueous systems was investigated over long operational periods (up to 155 days). For in situ deployments, simultaneous removal of the petroleum hydrocarbons (>90% in term of degradation efficiency) and bromate, used as catholyte, (up to 79%) with concomitant biogenic electricity generation (peak power density up to 6.75 mWm−2) were obtained at a hydraulic retention time (HRT) of 10 days. The tubular MFC could be operated successfully at copiotrophic (100 ppm phenanthrene, 2000 ppm benzene at HRT 30 days) and oligotrophic (phenanthrene and benzene, 50 ppb each, HRT 10 days) substrate conditions suggesting its effectiveness and robustness at extreme substrate concentrations in anoxic environments. In the MFC designed for ex situ deployments, optimum MFC performance was obtained at HRT of 30 h giving COD removal and maximum power output of approximately 77% and 6.75 mWm−2 respectively. The MFC exhibited the ability to resist organic shock loadings and could maintain stable MFC performance. Results of this study suggest the potential use of MFC technology for possible in situ/ex situ hydrocarbon-contaminated groundwater treatment or refinery effluents clean-up, even at extreme contaminant level conditions

    Selection of diazotrophic bacterial communities in biological sand filter mesocosms used for the treatment of phenolic-laden wastewater

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    Agri effluents such as winery or olive mill waste-waters are characterized by high phenolic concentrations. These compounds are highly toxic and generally refractory to biodegradation. Biological sand filters (BSFs) represent inexpensive, environmentally friendly, and sustainable wastewater treatment systems which rely vastly on microbial catabolic processes. Using denaturing gradient gel electrophoresis and terminal-restriction fragment length polymorphism, this study aimed to assess the impact of increasing concentrations of synthetic phenolic-rich wastewater, ranging from 96 mg L−1 gallic acid and138 mg L−1 vanillin (i.e., a total chemical oxygen demand (COD) of 234 mg L−1) to 2,400mg L−1 gallic acid and 3,442 mg L−1 vanillin (5,842 mg COD L−1), on bacterialcommunities and the specific functional diazotrophic community from BSF mesocosms. This amendment procedure instigated efficient BSF phenolic removal, significant modifications of the bacterial communities, and notably led to the selection of a phenolic-resistant and less diverse diazotrophic community. This suggests that bioavailable N is crucial in the functioning of biological treatment processes involving microbial communities, and thus that functional alterations in the bacterial communities in BSFs ensure provision of sufficient bioavailable nitrogen for the degradation of wastewater with a high C/N ratio.Web of Scienc

    Enhanced biodegradation of PAHs in historically contaminated soil by M. gilvum inoculated biochar

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    The inoculation of rice straw biochar with PAH-degrading Mycobacterium gilvum (1.27 × 1011 ± 1.24 × 1010 cell g−1), and the subsequent amendment of this composite material to PAHs contaminated (677 mg kg−1) coke plant soil, was conducted in order to investigate if would enhance PAHs biodegradation in soils. The microbe-biochar composite showed superior degradation capacity for phenanthrene, fluoranthene and pyrene. Phenanthrene loss in the microbe-biochar composite, free cell alone and biochar alone treatments was, respectively, 62.6 ± 3.2%, 47.3 ± 4.1% and non-significant (P > 0.05); whereas for fluoranthene loss it was 52.1 ± 2.3%; non-significant (P > 0.05) and non-significant (P > 0.05); and for pyrene loss it was 62.1 ± 0.9%; 19.7 ± 6.5% and 13.5 ± 2.8%. It was hypothesized that the improved remediation was underpinned by i) biochar enhanced mass transfer of PAHs from the soil to the carbonaceous biochar “sink”, and ii) the subsequent degradation of the PAHs by the immobilized M. gilvum. To test this mechanism, a surfactant (Brij 30; 20 mg g−1 soil), was added to impede PAHs mass transfer to biochar and sorption. The surfactant increased solution phase PAH concentrations and significantly (P < 0.05) reduced PAH degradation in the biochar immobilized M. gilvum treatments; indicating the enhanced degradation occurred between the immobilized M. gilvum and biochar sorbed PAHs

    Assessment of Arthrobacter viscosus as reactive medium for forming permeable reactive biobarrier applied to PAHs remediation

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    Polycyclic aromatic hydrocarbons (PAHs) are significant environmental contaminants as they are present naturally as well as anthropogenically in soil, air and water. In spite of their low solubility, PAHs are spread to the environment, and they are present in surface water, industrial effluent or groundwater. Amongst all remediation technologies for treating groundwater contaminated with PAHs, the use of a permeable reactive biobarrier (PRBB) appears to be the most cost-effective, energy efficient, and environmentally sound approach. In this technology, the microorganisms are used as reactive medium to degrade or stabilize the contaminants. The main limits of this approach are that the microorganisms or consortium used for forming the PRBB should show adequate characteristics. They must be retained in the barrier-forming biofilm, and they should also have degradative ability for the target pollutants. The aim of the present work is to evaluate the viability of Arthrobacter viscosus as bioreactive medium for forming PRBB. Initially, the ability of A. viscosus to remove PAHs, benzo[a]anthracene 100 μM and phenanthrene 100 μM was evaluated operating in a batch bench-scale bioreactor. In both cases, total benzo[a]anthracene and phenanthrene removals were obtained after 7 and 3 days, respectively. Furthermore, the viability of the microorganisms was evaluated in the presence of chromium in a continuous mode. As a final point, the adhesion of A. viscosus to sepiolite forming a bioreactive material to build PRBB was demonstrated. In view of the attained results, it can be concluded that A. viscosus could be a suitable microorganism to form a bioreactive medium for PAHs remediation.This work has been supported by the Spanish Ministry of Economy and Competitiveness and FEDER Funds (Project CTM 2011-25389). Marta Pazos received financial support under the Ramon y Cajal programme and Marta Cobas under the final project master grant "Campus do Mar Knowledge in depth"

    Electrokinetic Remediation of Metal-Contaminated Soils: Influence of Operating Variables

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    The Geo-Institute (G-I) of the American Society of Civil Engineers (ASCE)Geo-EnvironMeet 2025: Geoenvironmental Contamination and Waste Containment -- 2 March 2025 through 5 March 2025 -- Louisville -- 207186Soil pollution is a global concern due to its direct influence on agriculture and food security which needs immediate attention. Electrokinetic Remediation (EKR) is one of the emerging technologies for contaminant removal from soil with the application of direct current electricity. This study investigated the effect of operating variables of EKR, including voltage, electrolyte solution, and electrode material on artificially contaminated soils with Hexavalent Chromium [Cr (VI)] and Lead [Pb (II)]. Results of the study indicated that applied voltage had a profound effect on the removal efficiency of EKR with a maximum removal of 55% and 64% for Cr (VI) and Pb, respectively, at 2.5 V/cm. However, with ethylenediaminetetraacetic acid (EDTA), the removal rate for Cr (VI) (77%) was higher as compared to Pb (65%). Similarly, the behavior of electrode material exhibited contrasting results, with graphite more suited for Cr (VI), while stainless steel for Pb removal. The findings suggested that the operating conditions vary with the type of metal contaminant present. © ASCE

    Genome-wide analysis of Sphingomonas wittichii RW1 behaviour during inoculation and growth in contaminated sand.

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    The efficacy of inoculation of single pure bacterial cultures into complex microbiomes, for example, in order to achieve increased pollutant degradation rates in contaminated material (that is, bioaugmentation), has been frustrated by insufficient knowledge on the behaviour of the inoculated bacteria under the specific abiotic and biotic boundary conditions. Here we present a comprehensive analysis of genome-wide gene expression of the bacterium Sphingomonas wittichii RW1 in contaminated non-sterile sand, compared with regular suspended batch growth in liquid culture. RW1 is a well-known bacterium capable of mineralizing dibenzodioxins and dibenzofurans. We tested the reactions of the cells both during the immediate transition phase from liquid culture to sand with or without dibenzofuran, as well as during growth and stationary phase in sand. Cells during transition show stationary phase characteristics, evidence for stress and for nutrient scavenging, and adjust their primary metabolism if they were not precultured on the same contaminant as found in the soil. Cells growing and surviving in sand degrade dibenzofuran but display a very different transcriptome signature as in liquid or in liquid culture exposed to chemicals inducing drought stress, and we obtain evidence for numerous 'soil-specific' expressed genes. Studies focusing on inoculation efficacy should test behaviour under conditions as closely as possible mimicking the intended microbiome conditions

    Soil–Water Interactions and Arsenic Enrichment in Groundwater

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    Over the past decades, population boom, urbanization, and industrialization have overburdened the surface water sources rendering them non-potable for consumption. A switch to relatively safer groundwater resource, to meet the demand for drinking and other activities, has led to a significant effect on its quality and quantity. Overextraction of groundwater has led to decline in the water table, thus, exposing it to contaminants that seep in from the soil surface, particularly during seepage of surface water. Considering the toxicity of pollutants in groundwater, particularly the inorganic pollutants like heavy metals, arsenic (As) in groundwater possess a serious threat to the exposed population. The source of arsenic in groundwater has been reported to be geogenic in nature; however, organic matter inflow by anthropogenic sources facilitated by microbial degradation of minerals (Fe and Mn) releases the soil-absorbed arsenic into the groundwater. In India, As has been reported in the belt of Ganga-Brahmaputra plains including West Bengal, Bihar, Chhattisgarh, and the North-Eastern states. Scientific investigations in these regions have identified As concentration greater than the acceptable limit of 10 ?g/L, leaving 360 million people vulnerable to groundwater As contamination. Arsenic can cause a wide range of chronic and acute illness when consumed in concentration above 10 ?g/L in inorganic form, which usually occurs as trivalent arsenite (arsenous acid, As(III), H 3 AsO 3) or pentavalent arsenate (arsenic acid, As(V), H 3 AsO 4). The inorganic As is absorbed by the kidney, liver, and lungs and gets deposited in tissues of nails, hair, and skin. Long-term exposure of As can cause pigmentation changes, skin lesions, or hyperkeratosis. Alternatively, As-free groundwater sources and removal of As from the existing water source are the only viable options to prevent arsenic toxicity. Using alternative sources, like, harvested rainwater or reclaimed wastewater for irrigation can help to prevent As exposure to soil and crops. The crisis of arsenic poisoning can be curbed with techniques like cost-effective watershed treatment along with creating proper awareness. © 2023 John Wiley & Sons Ltd. Published 2023 by John Wiley & Sons Ltd. All rights reserved

    Effect of surface-tailored biocompatible organoclay on the bioavailability and mineralization of polycyclic aromatic hydrocarbons in long-term contaminated soil

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    A surface-tailored organoclay (palmitic acid-tailored Arquad®-modified bentonite, ABP) was prepared for the selective adsorption of cadmium in the presence of polycyclic aromatic hydrocarbon (PAH) contaminants in a long-term contaminated soil. The efficiency of the organoclay (ABP) and the effect of its parent clays were assessed concerning the microbial viability, metal immobilization and PAHs bioavailability and biodegradation in a long-term (70 days) soil incubation study. The surface-tailored organoclay (ABP) increased the bacterial growth by 5–7 fold than the control and parent clay-amended soil. With an increased effect of aging, the ABP immobilized more Cd from the soil solution (2-folds higher than the control soil), and simultaneously increased the bioavailability (1.6–1.8 fold) of low molecular weight PAHs related to the control soil and the parent clay-amended soils. The surface-tailored organoclay (ABP) could also increase the mineralization of 14C-labeled phenanthrene by ca. 1.3-fold relative to the control experiment under a 25-days of incubation

    Soil biota in boreal urban greenspace : Responses to plant type and age

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    Plant functional type influences the abundance and distribution of soil biota. With time, as root systems develop, such effects become more apparent. The relationship of plant type and time with the structure and abundance of soil microbial and invertebrate communities has been widely investigated in a variety of systems. However, much less is known about long-term soil community dynamics within the context of urban environments. In this study, we investigated how soil microbes, nematodes and earthworms respond to different plant functional types (lawns only and lawns with deciduous or evergreen trees) and park age in 41 urban parks in southern Finland. As non-urban controls we included deciduous and evergreen trees in 5 forest sites. We expected that microbial biomass and the relative abundance of fungi over bacteria would increase with time. We also expected major differences in soil microbial and nematode communities depending on vegetation: we hypothesized that i) the presence of trees, and evergreens in particular, would support a greater abundance of fungi and fungal-feeding nematodes over bacteria and bacterial-feeding nematodes and ii) the fungi to bacteria ratio would be lowest in lawns, with deciduous trees showing intermediate values. In contrast to our predictions, we showed that old deciduous trees, rather than evergreens, supported the highest fungal abundances and fungal-feeding nematodes in the soil. Consistent with our predictions, microbial biomass in urban park soils tended to increase with time, whereas - in contrast to our hypotheses - fungal-feeding nematode abundance declined. Even in the oldest parks included in the current study, microbial biomass estimates never approximated those in the minimally managed natural forests, where biomass estimates were three times higher. Anecic earthworm abundance also increased with time in urban parks, whereas abundances of fungal-feeding, plant-feeding and omnivorous nematodes, as well as those of epigeic and endogeic earthworms remained constant with time and without any distinct differences between urban parks and the control forests. Our findings highlight that although urban park soils harbor diverse soil communities and considerable microbial biomass, they are distinct from adjacent natural sites in community composition and biomass.Peer reviewe
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