WorldWideScience

Sample records for aeration carbon source

  1. Minimization of nitrous oxide emission from CASS process treating low carbon source domestic wastewater: Effect of feeding strategy and aeration rate.

    Science.gov (United States)

    Liang, Weihao; Yu, Chao; Ren, Hongqiang; Geng, Jinju; Ding, Lili; Xu, Ke

    2015-12-01

    Nitrous oxide (N2O) emission during wastewater treatment can be mitigated by improving operational conditions, e.g., organic carbon supply and dissolved oxygen. To evaluate the control parameters for N2O emission in the low carbon source domestic wastewater treatment process, N2O emissions from Cyclic Activated Sludge System (CASS) under different feeding strategies and aeration rates were investigated. Results showed that continuous feeding enhanced nitrogen removal and reduced N2O emission compared to batch feeding, while a higher aeration rate led to less N2O emission. N2O was mainly produced during non-aeration phases in batch feeding CASS and the amount of N2O generated from denitrification decreased under continuous feeding, indicating that carbon source in the continuous influent relieved the electron competition between denitrification reductases during non-aeration phase. Moreover, taxonomic analysis based on high-throughput 16S rRNA gene sequencing revealed higher abundance of denitrifying bacteria, especially N2O-reducing bacteria in continuous feeding CASS. PMID:26386420

  2. Influence of COD/N ratio and carbon source on nitrogen removal in a structured-bed reactor subjected to recirculation and intermittent aeration (SBRRIA).

    Science.gov (United States)

    Santos, Carla E D; Moura, Rafael B; Damianovic, Márcia H R Z; Foresti, Eugenio

    2016-01-15

    This study aimed to evaluate the influence of COD/N ratio and carbon source on simultaneous nitrogen and carbon removal processes. A continuous up-flow structured-bed reactor subjected to recirculation and intermittent aeration (SBRRIA) was operated with hydraulic retention time (HRT) of 11.2 ± 0.6 h. The carbon sources were meat peptone and sucrose. The COD/N ratio varied by maintaining the organic loading rate fixed at 1.07 kg COD m(-3) d(-1) and changing the total-N concentration. The COD/N ratios tested were 9.7 ± 1 (sucrose); 7.6 ± 1 (meat peptone); 2.9 ± 1 (meat peptone) and 2.9 ± 0.4 (sucrose). COD removal efficiencies remained above 90% in all experimental phases. At lower COD/N ratios, NH4(+)-N oxidation efficiencies were higher than 90%. An autotrophic metabolism by anammox process was observed in Phases III and IV, which was responsible for 35% and 27% of total-N loading removal rates, respectively. Therefore, the system achieved total nitrogen removal efficiencies of 84.6 ± 10.1 and 81.5 ± 5.3%, under low availability of organic electron donors. PMID:26595179

  3. Redox driven metabolic tuning: Carbon source and aeration affect synthesis of poly(3-hydroxybutyrate) in Escherichia coli

    OpenAIRE

    Nikel, Pablo I.; de Almeida, Alejandra; Giordano, Andrea M.; Pettinari, M. Julia

    2010-01-01

    Growth and polymer synthesis were studied in a recombinant E. coli strain carrying phaBAC and phaP of Azotobacter sp. strain FA8 using different carbon sources and oxygen availability conditions. The results obtained with glucose or glycerol were completely different, demonstrating that the metabolic routes leading to the synthesis of the polymer when using glycerol do not respond to environmental conditions such as oxygen availability in the same way as they do when other substrates, such as...

  4. Physiology of Aspergillus niger in Oxygen-Limited Continuous Cultures: Influence of Aeration, Carbon Source Concentration and Dilution Rate

    DEFF Research Database (Denmark)

    Diano, Audrey; Peeters, J.; Dynesen, Jens Østergaard;

    2009-01-01

    of low oxygen availability, at different carbon source concentrations and at different specific growth rates, on the metabolism of A. niger, using continuous cultures. The results show that there is an increase in the production of tricarboxylic acid (TCA) cycle intermediates at low oxygen concentrations....... Indeed, at these conditions, a decrease in the mitochondrial respiratory chain activity leads to an accumulation of NADH and to a decreased ATP production which uncouples catabolism and anabolism, influences the intracellular pH and leads to production and excretion of organic acids. Moreover, mannitol...... is being produced in order to ensure reoxidation of NADH, and this is the main cellular response to balance the ratio NADH/NAD at low oxygen availability. Mannitol production is also coupled to low specific growth rate, which suggests a control of carbon catabolite repression on the mannitol pathway...

  5. Nitrogen removal in a Sequencing Batch Biofilm Reactor : effect of carbon availability and intermittent aeration

    OpenAIRE

    Vieira, Maria Madalena Costa; Brito, A. G.; R. Nogueira

    2009-01-01

    This study aimed to investigate the effects of carbon availability and intermittent aeration on nitrogen removal in a Sequencing Batch Biofilm Reactor (SBBR). The percentage of nitrogen removal in the SBBRs operating with dump fill and slow fill with optimum intermittent aeration was quite similar, 75.7% and 69.2%, respectively, indicating that intermittent aeration allowed a considerable energy saving without compromising significantly nitrogen removal. Accumulation of stor...

  6. Gas transfer rates from airlifts used for concurrent aeration, carbon dioxide stripping, and recirculation

    Science.gov (United States)

    Airlifts simplify recirculating aquaculture systems and can potentially reduce capital costs and minimize maintenance issues. Airlifts have the ability to move and aerate water as well as degass the water of any carbon dioxide. This study evaluated the oxygen transfer and carbon dioxide removal abil...

  7. Flow, aeration, and carbon dioxide transfer rates for airlifts used in recirculating aquaculture systems

    Science.gov (United States)

    Airlift pumping systems reduce the electrical costs of moving water in a recirculating aquaculture system and can be concurrently designed to aerate water and remove carbon dioxide. This study determined the water flow, oxygen transfer, and CO2 removal rates for water using airlift technology in a 1...

  8. Simultaneous removal of COD and nitrogen using a novel carbon-membrane aerated biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A membrane aerated biofilm reactor is a promising technology for wastewater treatment. In this study, a carbon-membrane aerated biofilm reactor (CMABR) has been developed, to remove carbon organics and nitrogen simultaneously from one reactor. The results showed that CMABR has a high chemical oxygen demand (COD) and nitrogen removal efficiency, as it is operated with a hydraulic retention time (HRT) of 20 h, and it also showed a perfect performance, even if the HRT was shortened to 12 h. In this period, the removal efficiencies of COD, ammonia nitrogen (NH4+-N), and total nitrogen (TN) reached 86%, 94%, and 84%, respectively. However,the removal efficiencies of NH4+-N and TN declined rapidly as the HRT was shortened to 8 h. This is because of the excessive growth of biomass on the nonwoven fiber and very high organic loading rate. The fluorescence in situ hybridization (FISH) analysis indicated that the ammonia oxidizing bacteria (AOB) were mainly distributed in the inner layer of the biofilm. The coexistence of AOB and eubacteria in one biofilm can enhance the simultaneous removal of COD and nitrogen.

  9. BIOLOGICAL AERATED FILTERS (BAFs FOR CARBON AND NITROGEN REMOVAL: A REVIEW

    Directory of Open Access Journals (Sweden)

    ELSHAFIE AHMED

    2012-08-01

    Full Text Available Biological aerated filters (BAFs are an emerging wastewater treatment technology designed for a wide range of municipal and industrial applications. This review paper presents and discusses of the influence C/N ratio, nitrification and denitrification principle, effect of pH, DO and alkalinity on the nitrification and denitrification systems, organic and hydraulic loading of BAF reactor, etc. Results from upflow and downflow biofilter pilot at different condition, with nitrification and denitrification are reviewed. Under the optimal conditions, significant amount of COD, ammonia-nitrogen and total nitrogen were removed. Removal rates based on reactor volume for different carbon-aceous COD and ammonia loading rate are reported. The BAF system for the nitrification and denitrification processes for carbon and nitrogen removal from the wastewater need to be evaluated and applied properly to protect of our environment and resources.

  10. Feasibility study of an aeration treatment system in a raw water storage reservoir used as a potable water source

    OpenAIRE

    Fronk, Robert Charles

    1996-01-01

    The systems engineering process has been utilized to determine the feasibility of an aeration treatment system for a raw water storage reservoir used as a potable water source. This system will be used to ensure a consistently high quality of raw water by the addition of dissolved oxygen into the reservoir. A needs analysis establishes the importance and requirements for a consistently high quality of raw water used as a source for a potable water treatment facility. This s...

  11. Modeling Aerobic Carbon Source Degradation Processes using Titrimetric Data and Combined Respirometric-Titrimetric Data: Experimental Data and Model Structure

    DEFF Research Database (Denmark)

    Gernaey, Krist; Petersen, B.; Nopens, I.;

    2002-01-01

    Experimental data are presented that resulted from aerobic batch degradation experiments in activated sludge with simple carbon sources (acetate and dextrose) as substrates. Data collection was done using combined respirometric-titrimetric measurements. The respirometer consists of an open aerate...

  12. Identification of the mechanism limiting the alteration of clad spent fuel segments in aerated carbonated groundwater

    Science.gov (United States)

    Jégou, C.; Peuget, S.; Broudic, V.; Roudil, D.; Deschanels, X.; Bart, J. M.

    2004-03-01

    Leaching experiments were performed with five spent fuel samples (20 mm segments of clad fuel rods) from French power reactors (four UO 2 fuel samples with burnup ratings of 22, 37, 47 and 60 GW d t HM-1 and a MOX fuel sample irradiated to 47 GW d t HM-1) to determine the release kinetics of the matrix containing most of the radionuclides. The experiments were carried out with carbonated groundwater on previously leached sections of clad fuel rods in static mode, in an aerated medium at room temperature (25 °C) in a hot cell. Until 313 days of leaching and below uranium saturation, the Sr/U congruence ratios for all the UO 2 fuel samples ranged from 1 to 2; allowing for the experimental uncertainty, strontium can thus be considered as a satisfactory matrix alteration tracer. No significant burnup effect was observed on the alteration of the UO 2 fuel matrix. The daily strontium release factor was approximately 2.7 × 10 -8 d -1 for UO 2 fuel after 706 days of leaching, and seven to eight times higher for MOX fuel. Several alteration mechanisms (radiolysis, solubility, precipitation/clogging) are examined to account for the experimental findings. All the available experimental data (characterization of secondary phases and leaching data) indicate that the mechanism limiting the spent fuel alteration kinetics, for the conditions studied, is likely based on the transport and accessibility of oxidizing species and/or water within the segment.

  13. Identification of the mechanism limiting the alteration of clad spent fuel segments in aerated carbonated groundwater

    International Nuclear Information System (INIS)

    Leaching experiments were performed with five spent fuel samples (20 mm segments of clad fuel rods) from French power reactors (four UO2 fuel samples with burnup ratings of 22, 37, 47 and 60 GW d tHM-1 and a MOX fuel sample irradiated to 47 GW d tHM-1) to determine the release kinetics of the matrix containing most of the radionuclides. The experiments were carried out with carbonated groundwater on previously leached sections of clad fuel rods in static mode, in an aerated medium at room temperature (25 deg. C) in a hot cell. Until 313 days of leaching and below uranium saturation, the Sr/U congruence ratios for all the UO2 fuel samples ranged from 1 to 2; allowing for the experimental uncertainty, strontium can thus be considered as a satisfactory matrix alteration tracer. No significant burnup effect was observed on the alteration of the UO2 fuel matrix. The daily strontium release factor was approximately 2.7 x 10-8 d-1 for UO2 fuel after 706 days of leaching, and seven to eight times higher for MOX fuel. Several alteration mechanisms (radiolysis, solubility, precipitation/clogging) are examined to account for the experimental findings. All the available experimental data (characterization of secondary phases and leaching data) indicate that the mechanism limiting the spent fuel alteration kinetics, for the conditions studied, is likely based on the transport and accessibility of oxidizing species and/or water within the segment

  14. Solar powered dugout aeration

    International Nuclear Information System (INIS)

    Pasture dugouts are a significant source of water for livestock on the Canadian Prairies and as such, must maintain the best water quality possible. Aeration improves the water quality and is part of a good management plan to reduce overall water treatment costs. Although dugouts can be aerated naturally through wind and wave action and photosynthesis, this generally aerates only the top portion of the dugout. Artificial aeration by air injection into the lowest point of the dugout ensures that the water is oxygenated throughout the entire dugout. Solar aeration can be used in remote areas where grid power is not practical. With solar powered aeration systems, solar panels are used to generate the electrical power needed to run the compressor while storing excess energy in batteries. A solar aeration system includes solar panels, deep cycle batteries to store excess power, a control board with a regulator, a compressor, a weighed feeder hose, and an air diffuser. This publication presented the design of a solar aeration system and its cost. 1 tab., 3 figs

  15. Nitrous oxide emissions from denitrification and the partitioning of gaseous losses as affected by nitrate and carbon addition and soil aeration

    International Nuclear Information System (INIS)

    The factors controlling nitrous oxide (N2O) emissions vary with different soil and environmental conditions and management practices. This study was conducted to determine the importance of soil aeration, nitrate (NO3) addition, carbon (C) additions, and C sources on gaseous nitrogen (N) losses from the denitrification of arable soils at a potato farm in Atlantic Canada. Denitrification and N2O emissions were measured using acetylene inhibition. An N2O and nitrogen gas (N2) ratio of 0.7 showed that most emissions occurred as N2O. Emissions at water-filled pore spaces (WFPs) of 0.45 m3 per m3 were negligible. N2O emissions increased with NO3 and C additions. Results suggested that soil aeration plays a dominant role in controlling the magnitude of denitrification and N2O emissions. However, soil NO3 supplies in this study did not limit the denitrification process. The study showed that N2O emissions are controlled by C availability when there is a high degree of soil disturbance and high fertilizer N inputs. The relationship between the demand and supply of terminal electron acceptors (TEAs) was used to explain the spatial distribution of the N2O emissions. Higher WFPs and lower soil NO3 concentrations resulted in higher rates of total denitrification. It was concluded that further research is needed to examine the role of overall soil and crop management in relation to C availability when developing mitigation strategies. 52 refs., 4 tabs

  16. Carbon dioxide stimulates the production of amylovorin L by Lactobacillus amylovorus DCE 471, while enhanced aeration causes biphasic kinetics of growth and bacteriocin production.

    Science.gov (United States)

    Neysens, Patricia; De Vuyst, Luc

    2005-11-25

    The effects of both oxygen and carbon dioxide on growth of and product formation by Lactobacillus amylovorus DCE 471, a promising new sourdough starter culture, were assessed through controlled, in vitro fermentation experiments, using a temperature of 37 degrees C and a constant pH of 5.4. It was seen that aeration affected both cell growth and amylovorin L production. At aeration rates of 1 l min(-1) and more, the bacterial population was subjected to oxidative stress as reflected by biphasic growth patterns. During the first growth phase, the maximum specific growth rate increased with increasing aeration rates stabilizing at the highest oxygen concentrations. The maximum obtainable cell yields decreased. During the second growth phase, the amylovorin L production was stimulated at the highest aeration. However, amylovorin titers were never higher in the presence of oxygen compared with the anaerobic fermentations. Carbon dioxide did not influence cell growth of L. amylovorus DCE 471. The maximum specific growth rate and the biomass concentrations were merely affected. On the other hand, the maximum soluble bacteriocin titers coincided with the highest carbon dioxide flow rates. These results indicate that mild aeration of type II sourdoughs might enhance both cell yield and amylovorin L production by L. amylovorus DCE 471, thereby contributing to the competitiveness of the strain. Growth in an ecosystem together with yeasts producing carbon dioxide might exert a positive effect on the production of amylovorin L as well. PMID:16087265

  17. AERATION OF THE ICE-COVERED WATER POOLS USING THE WAVE FLOW AERATOR

    OpenAIRE

    Solomin E.E; Sirotkin E.A.; SolominE.V.

    2013-01-01

    This article describes the technical advantages and economic benefits of the ice-covered pool aeration plants consuming power from renewable energy sources. We made a comparative evaluation of the wave flow-aeration method and other methods of pool aeration. We showed the indexes and the characteristics of the wave flow-maker for aeration of ice-covered pools on the territory of Russia. We also made calculations of the economic benefits of aeration plants using the devices converting renewabl...

  18. Gamma radiolytic decomposition of endosulfan in aerated solution: the role of carbonate radical.

    Science.gov (United States)

    Shah, Noor S; Khan, Javed Ali; Al-Muhtaseb, Ala'a H; Sayed, Murtaza; Khan, Hasan M

    2016-06-01

    The present study elaborates the removal of endosulfan, an emerging water pollutant and potential carcinogenic, in aerated solution. The influence of Cl(-), NO3 (-), NO2 (-), CO3 (2-), HCO3 (-), SO3 (2-), and humic acid was assessed on the radiolytic degradation of endosulfan. A strong inhibition on the radiolytic degradation of endosulfan was observed in the presence of NO3 (-), NO2 (-), and SO3 (2-). Instead, a slight increase in the removal efficiency of endosulfan was observed at high concentrations of CO3 (2-) and HCO3 (-). The formation of CO3 (•-) in radiolytic degradation of endosulfan in the presence of CO3 (2-) and HCO3 (-) was demonstrated by adding SO3 (2-) that rapidly react with CO3 (•-). The results indicate that CO3 (•-) formed from the reactions of CO3 (2-) and HCO3 (-) and commonly found in natural water can play an important role in the degradation of endosulfan and other sulfur containing electron-rich compounds. The study showed faster degradation of endosulfan at lower concentration compared to high concentration and removal was found to follow pseudo-first-order kinetic. Endosulfan ether was found as the main degradation product and degradation pathway was found to be initiated at the S=O bond of endosulfan. The efficiency of gamma irradiation in the removal of endosulfan was examined in terms of formation of short chain organic acids and chloride ion accumulation. PMID:26979317

  19. Aeration equipment for small depths

    Science.gov (United States)

    Sluše, Jan; Pochylý, František

    2015-05-01

    Deficit of air in water causes complications with cyanobacteria mainly in the summer months. Cyanobacteria is a bacteria that produces poison called cyanotoxin. When the concentration of cyanobacteria increases, the phenomena "algal bloom" appears, which is very toxic and may kill all the organisms. This article describes new equipment for aeration of water in dams, ponds and reservoirs with small depth. This equipment is mobile and it is able to work without any human factor because its control is provided by a GPS module. The main part of this equipment consists of a floating pump which pumps water from the surface. Another important part of this equipment is an aerator where water and air are blended. Final aeration process runs in the nozzles which provide movement of all this equipment and aeration of the water. Simulations of the flow are solved by multiphase flow with diffusion in open source program called OpenFOAM. Results will be verified by an experiment.

  20. Emissions of ammonia, carbon dioxide, and hydrogen sulfide from swine wastewater during and after acidification treatment: effect of pH, mixing and aeration

    DEFF Research Database (Denmark)

    Dai, Xiao-Rong; Blanes-Vidal, Victoria

    2013-01-01

    This study aimed at evaluating the effect of swine slurry acidification and acidification-aeration treatments on ammonia (NH(3)), carbon dioxide (CO(2)) and hydrogen sulfide (H(2)S) emissions during slurry treatment and subsequent undisturbed storage. The study was conducted in an experimental...... setup consisting of nine dynamic flux chambers. Three pH levels (pH = 6.0, pH = 5.8 and pH = 5.5), combined with short-term aeration and venting (with an inert gas) treatments were studied. Acidification reduced average NH(3) emissions from swine slurry stored after acidification treatment compared to...... emissions during storage of non-acidified slurry. The reduction were 50%, 62% and 77% when pH was reduce to 6.0, 5.8 and 5.5, respectively. However, it had no significant effect on average CO(2) and H(2)S emissions during storage of slurry after acidification. Aeration of the slurry for 30 min had no effect...

  1. Performance of organics and nitrogen removal in subsurface wastewater infiltration systems by intermittent aeration and shunt distributing wastewater.

    Science.gov (United States)

    Pan, Jing; Yuan, Fang; Yu, Long; Huang, Linli; Fei, Hexin; Cheng, Fan; Zhang, Qi

    2016-07-01

    Organics and nitrogen removal in four subsurface wastewater infiltration systems (SWISs), named SWIS A (without intermittent aeration and shunt distributing wastewater), SWIS B (with intermittent aeration), SWIS C (with shunt distributing wastewater) and SWIS D (with intermittent aeration and shunt distributing wastewater) was investigated. High average removal rates of 92.3% for COD, 90.2% for NH4-N and 88.1% for TN were achieved simultaneously in SWIS D compared with SWIS A, B and C. The excellent TN removal of SWIS D was due to intermittent aeration provided sufficient oxygen for nitrification in upper matrix and the favorable anoxic or anaerobic environment for denitrification in subsequent matrix, and moreover, shunt distributing wastewater provided sufficient carbon source for denitrification process. The results indicated that intermittent artificial aeration combined with shunt distributing wastewater could achieve high organics and nitrogen removal in SWISs. PMID:27039353

  2. Effects of carbon sources, oxygenation and ethanol on the production of inulinase by Kluyveromyces marxianus YX01

    Directory of Open Access Journals (Sweden)

    JIAOQI GAO

    2012-01-01

    Full Text Available Inulinase is one of the most important factors in consolidated bioprocessing, which combines enzyme production, inulin saccharification, and ethanol fermentation into a single process. In our study, inulinase production and cell growth of Kluyveromyces marxianus YX01 under different conditions were studied. Carbon source was shown to be significant on the production of inulinase, because the activity of inulinase was higher using inulin as a carbon source compared with glucose or fructose. The concentration of the carbon source had a repressive effect on the activity of inulinase. When the concentration was increased to 60 g/L, inulinase activity was only 50% compared with carbon source concentration of 20 g/L. Enzyme activity was also strongly influenced by aeration rate. It has been shown that the activity of inulinase and cell growth under anaerobic conditions were maintained at low levels, but aeration at 1.0 vvm (air volume/broth volume minute led to higher activity. Inulinase activity per unit biomass was not significantly different under different aeration rates. Ethanol had a repressive effect on the cell growth. Cells ceased growing when the level of ethanol was greater than 9% (v/v, but ethanol did not affect the activity of secreted inulinase and the enzyme was stable at ethanol concentration up to 15%.

  3. DETERMINATION METHODOLOGY OF BIOMASS AND PAC AT AERATION UNIT IN PACT PROCESS

    OpenAIRE

    N.Jaffarzadeh; A. Mesdaghinja; S. Nasserj; M.Shariat; A. Messbah

    2000-01-01

    In this research using two pilot scale systems of activated sludge (AS) and powdered activated carbon technology (PACT), the soluble organic load removal efficiency was evaluated, for a synthetic wastewater with mono-ethylene glycol as carbon source. Also, the variations of biomass and PAC in each reactor were studied and the relative accuracy of differential ignition method for determining the amount of biomass and powdered activated carbon (combined in aeration unit of the PACT pilot) was i...

  4. ASPECTS REGARDING THE METHODS OF SOIL AERATION

    OpenAIRE

    A. UNGURAŞU; A. UNGUREANU

    2011-01-01

    Aspects regarding the methods of soil aeration. Soil aeration is a process to be carried out continuously the gas exchange between soil and atmosphere. The process is done mainly by the movement of water inside and outside him. There are three major gases in the soil (nitrogen,oxygen and carbon dioxide). Soil air composition differs from that of air by higher CO2 content (0,3 to 0,5%). The air in the soil is very important for the dynamics of soil. Soil aeration is accomplished through mass f...

  5. Aeration equipment for small depths

    Directory of Open Access Journals (Sweden)

    Sluše Jan

    2015-01-01

    Full Text Available Deficit of air in water causes complications with cyanobacteria mainly in the summer months. Cyanobacteria is a bacteria that produces poison called cyanotoxin. When the concentration of cyanobacteria increases, the phenomena „algal bloom“ appears, which is very toxic and may kill all the organisms. This article describes new equipment for aeration of water in dams, ponds and reservoirs with small depth. This equipment is mobile and it is able to work without any human factor because its control is provided by a GPS module. The main part of this equipment consists of a floating pump which pumps water from the surface. Another important part of this equipment is an aerator where water and air are blended. Final aeration process runs in the nozzles which provide movement of all this equipment and aeration of the water. Simulations of the flow are solved by multiphase flow with diffusion in open source program called OpenFOAM. Results will be verified by an experiment.

  6. Aerator Placement Strategies

    Science.gov (United States)

    The purpose of this study was to determine the effects on fish production, water quality and economics of concentrating paddlewheel aeration in large commercial ponds, compared to the current method of aerator placement. Ten 17-acre ponds (approximately 600 X 1300 ft) were brought into the study in ...

  7. AERATION OF THE ICE-COVERED WATER POOLS USING THE WAVE FLOW AERATOR

    Directory of Open Access Journals (Sweden)

    Solomin E.E

    2013-12-01

    Full Text Available This article describes the technical advantages and economic benefits of the ice-covered pool aeration plants consuming power from renewable energy sources. We made a comparative evaluation of the wave flow-aeration method and other methods of pool aeration. We showed the indexes and the characteristics of the wave flow-maker for aeration of ice-covered pools on the territory of Russia. We also made calculations of the economic benefits of aeration plants using the devices converting renewable energy. The project can be scaled and extended to the territory of the CIS, Europe, USA and Canada in the changing climate conditions and the variety of feed reservoirs around the world.

  8. Comparison of Biomass and Lipid Production under Ambient Carbon Dioxide Vigorous Aeration and 3% Carbon Dioxide Condition Among the Lead Candidate Chlorella Strains Screened by Various Photobioreactor Scales

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Naoko [Univ. of Nebraska, Lincoln, NE (United States); Barnes, Austin [Univ. of Nebraska, Lincoln, NE (United States); Jensen, Travis [Univ. of Nebraska, Lincoln, NE (United States); Noel, Eric [Univ. of Nebraska, Lincoln, NE (United States); Andlay, Gunjan [Synaptic Research, Baltimore, MD (United States); Rosenberg, Julian N. [Johns Hopkins Univ., Baltimore, MD (United States); Betenbaugh, Michael J. [Johns Hopkins Univ., Baltimore, MD (United States); Guarnieri, Michael T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Oyler, George A. [Univ. of Nebraska, Lincoln, NE (United States); Johns Hopkins Univ., Baltimore, MD (United States); Synaptic Research, Baltimore, MD (United States)

    2015-09-01

    Chlorella species from the UTEX collection, classified by rDNA-based phylogenetic analysis, were screened based on biomass and lipid production in different scales and modes of culture. Lead candidate strains of C. sorokiniana UTEX 1230 and C. vulgaris UTEX 395 and 259 were compared between conditions of vigorous aeration with filtered atmospheric air and 3% CO2 shake-flask cultivation. We found that the biomass of UTEX 1230 produced 2 times higher at 652 mg L-1 dry weight under both ambient CO2 vigorous aeration and 3% CO2 conditions, while UTEX 395 and 259 under 3% CO2 increased to 3 times higher at 863 mg L-1 dry weight than ambient CO2 vigorous aeration. The triacylglycerol contents of UTEX 395 and 259 increased more than 30 times to 30% dry weight with 3% CO2, indicating that additional CO2 is essential for both biomass and lipid accumulation in UTEX 395 and 259.

  9. Characterization of dissolved organic matter during landfill leachate treatment by sequencing batch reactor, aeration corrosive cell-Fenton, and granular activated carbon in series

    International Nuclear Information System (INIS)

    Landfill leachate is generally characterized as a complex recalcitrant wastewater containing high concentration of dissolved organic matter (DOM). A combination of sequencing batch reactor (SBR) + aeration corrosive cell-Fenton (ACF) + granular activated carbon (GAC) adsorption in series was proposed for the purpose of removing pollutants in the leachate. Fractionation was also performed to investigate the composition changes and characteristics of the leachate DOM in each treatment process. Experimental results showed that organic matter, in terms of chemical oxygen demand (COD), 5-day biological oxygen demand (BOD5), and dissolved organic carbon (DOC), was reduced by 97.2%, 99.1%, and 98.7%, respectively. To differentiate the DOM portions, leachates were separated into five fractions by XAD-8 and XAD-4 resins: hydrophobic acid (HPO-A), hydrophobic neutral (HPO-N), transphilic acid (TPI-A), transphilic neutral (TPI-N), and hydrophilic fraction (HPI). The predominant fraction in the raw leachate was HPO-A (36% of DOC), while the dominant fraction in the final effluent was HPI (53% of DOC). Accordingly, macromolecules were degraded to simpler ones in a relatively narrow range below 1000 Da. Spectral and chromatographic analyses also showed that most humic-like substances in all fractions were effectively removed during the treatments and led to a simultaneous decrease in aromaticity.

  10. Assimilation of Cellulose-Derived Carbon by Microeukaryotes in Oxic and Anoxic Slurries of an Aerated Soil

    OpenAIRE

    Chatzinotas, Antonis; Schellenberger, Stefanie; Glaser, Karin; Kolb, Steffen

    2013-01-01

    Soil microeukaryotes may trophically benefit from plant biopolymers. However, carbon transfer from cellulose into soil microeukaryotes has not been demonstrated so far. Microeukaryotes assimilating cellulose-derived carbon in oxic and anoxic soil slurries were therefore examined by rRNA-based stable-isotope probing. Bacteriovorous flagellates and ciliates and, likely, mixotrophic algae and saprotrophic fungi incorporated carbon from supplemental [U-13C]cellulose under oxic conditions. A previ...

  11. Process of nitrogen transformation and microbial community structure in the Fe(0)-carbon-based bio-carrier filled in biological aerated filter.

    Science.gov (United States)

    Deng, Shihai; Li, Desheng; Yang, Xue; Zhu, Shanbin; Li, Jinlong

    2016-04-01

    Nitrogen pollutants in low-organic carbon wastewater are difficult to biodegrade. Therefore, the Fe(0)-carbon-based bio-carrier (FCBC) was firstly used as hydrogen producer in a biological-aerated filter (BAF) to make up for the lack of organic carbon in biological nitrogen removal. Physical and chemical properties of FCBC were detected and compared in this study. The nitrogen removal rate for low COD/TN ratio wastewater, nitrogen transformation process, and microbial communities in the FCBC filled in BAF were investigated. Results showed that the nitrogen removal rates was 0.38-0.41 kg N m(-3) day(-1) in the FCBC filled BAF and reached 0.62 kg N m(-3) day(-1) within the filter depth of 60-80 cm, under the conditions of the dissolved oxygen 3.5 ± 0.2 mg L(-1) and the inlet pH 7.2 ± 0.1. Hydrogenophaga (using hydrogen as electron donor), Sphaerotilus (absorbing [Fe(3+)]), Nitrospira (nitrificaion), and Nitrosomonas (ammonia oxidation) were found to be the predominant genera in the reactor. The reaction schemes in the FCBC filled in BAF was calculated: hydrogen and [Fe(3+)] were produced by Fe(0)-C galvanic cells in the FCBC, ammonia was oxidized into nitrate by Nitrosomonas and Nitrospira genera, hydrogen was used as electron donors by Hydrogenophaga genus to reduce nitrate into N2, and [Fe(3+)] was partly absorbed by Sphaerotilus and diverted via sludge discharging. PMID:26638971

  12. Assimilation of cellulose-derived carbon by microeukaryotes in oxic and anoxic slurries of an aerated soil.

    Science.gov (United States)

    Chatzinotas, Antonis; Schellenberger, Stefanie; Glaser, Karin; Kolb, Steffen

    2013-09-01

    Soil microeukaryotes may trophically benefit from plant biopolymers. However, carbon transfer from cellulose into soil microeukaryotes has not been demonstrated so far. Microeukaryotes assimilating cellulose-derived carbon in oxic and anoxic soil slurries were therefore examined by rRNA-based stable-isotope probing. Bacteriovorous flagellates and ciliates and, likely, mixotrophic algae and saprotrophic fungi incorporated carbon from supplemental [U-(13)C]cellulose under oxic conditions. A previous study using the same soil suggested that cellulolytic Bacteria assimilated (13)C of supplemental cellulose. Thus, it can be assumed that ciliates, cercozoa, and chrysophytes assimilated carbon by grazing upon and utilizing metabolic products of Bacteria that hydrolyzed cellulose in the soil slurries. PMID:23851095

  13. Effect of Inoculum Age, Carbon and Nitrogen Sources on the Production of Lipase by Candida Cylindracea 2031 in Batch Fermentation

    Directory of Open Access Journals (Sweden)

    I. M. Noor

    2006-06-01

    Full Text Available Production of extracellular lipase by Candida cylindracea DSMZ 2031  was studied in a seven liters batch bioreactor, using palm oil (PO, palmitic acid (PA, lauric acid (LA, olive oil (OO and cooking oil (CO as carbon source.   The effect of  carbon and nitrogen sources  were studied by measuring the lipase activity.  The maximum lipase activity was found to be 12.7 kLU on palm oil as carbon source, urea as nitrogen sources and at 36 h inoculum age. This was achieved at a temperature of 30o C, pH of 6.0, agitation speed of 500 rpm and aeration of 1vvm.

  14. A new method of inhibiting pollutant release from source water reservoir sediment by adding chemical stabilization agents combined with water-lifting aerator

    Institute of Scientific and Technical Information of China (English)

    Beibei Chai; Tinglin Huang; Weihuang Zhu; Fengying Yang

    2011-01-01

    Source water reservoirs easily become thermally and dynamically stratified.Internal pollution released from reservoir sediments is the main cause of water quality problems.To mitigate the internal pollution more effectively,a new method,which combined chemical stabilization with water lifting aerator (WLA) technology,was proposed and its efficiency in inhibiting pollutant release was studied by controlled sediment-water interface experiments.The results showed that this new method can inhibit pollutant release from sediment effectively.The values of mean efficiency (E) in different reactors 2#-5# (1# with no agent,2# 10 mg/L polymeric aluminum chloride (PAC) was added,3# 20 mg/L PAC was added,4# 30 mg/L PAC was added,5# 20 mg/L PAC and 0.2 mg/L palyacrylamide (PAM)were added) for PO43- were 35.0%,43.9%,50.4% and 63.6%,respectively.This showed that the higher the PAC concentration was,the better the inhibiting efficiency was,and PAM addition strengthened the inhibiting efficiency significantly.For Fe2+,the corresponding values of E for the reactors 2#-5# were 22.9%,47.2%,34.3% and 46.2%,respectively.The inhibiting effect of PAC and PAM on Mn release remained positive for a relatively short time,about 10 days,and was not so effective as for PO43- and Fe2+.The average efliciencies in inhibiting the release of UV254 were 35.3%,25.9%,35.5%,38.9% and 39.5% for reactors 2#-5#,respectively.The inhibiting mechanisms of the agents for different pollutants varied among the conditions and should be studied further.

  15. Aeration for the removal of Rn from small water supplies

    International Nuclear Information System (INIS)

    Aeration is an emerging technology for the removal of radon from small public and private water supplies. It offers advantages over granular activated carbon (GAC) by avoiding the retention of radon progeny which causes an elevated gamma exposure rate and a potential for low level radioactive waste generation. A new diffused bubble aeration technology also offers advantages over packed tower aeration in terms of economics, performance, and aesthetics. This paper reports on recent field data from twenty prototype diffused bubble aeration systems located in six northeastern states. Theoretical and actual performance will be discussed for flows ranging from point-of-entry (POE) up to 400 gpm. The technology is capable of removing greater than 99.9 percent of the raw water radon from these supplies. Removal is greater than that achieved with GAC or packed tower aeration

  16. Catfish production using intensive aeration

    Science.gov (United States)

    For the last 3 years, researchers at UAPB and NWAC have been monitoring and verifying production yields in intensively aerated catfish ponds with aeration rates greater than 6 hp/acre. We now have three years of data on commercial catfish production in intensively aerated ponds. With stocking densi...

  17. Bioethanol from different Finnish agricultural carbon sources

    Energy Technology Data Exchange (ETDEWEB)

    Kautola, H.; Kymaelaeinen, M.; Tokeensuu, L.; Alatalo, T. (HAMK University of Applied Sciences, Degree Programme in Biotechnology and Food Engineering, Haemeenlinna (Finland)); Caerdenas, R. (Universidad Central del Ecuador, Facultad Ciencias Quimicas, Escuela de Quimica, Av. America. Ciudadela Universitaria, Quito (Ecuador)); Siukola, K.; Naesi, J. (Suomen Biojalostus Oy, Renko (Finland))

    2007-07-01

    Bioethanol in fuel and its domestic production has become a great issue in Finland during the last few years. There has been discussion about what kind of raw materials should be used and are there any local priorities. In the years 2004-2007 local farmers in Haem e , in southern part of Finland, started to find alternative use for sugar beet due to drastic reduction of domestic sugar production in the near future. This was also the start of the experimental studies on bi oethanol production. The aim of the study was to find out how the change of carbon source will effect on bi oethanol yield. The bioethanol production was studied in laboratory scale using carbon sources of saccharose, glucose, sugar beet juice, sugar beet mash and barley hydrolysates pretreated with amylases, (beta-glucanase and xylanase). The yeast used was Saccharomyces sp. The pre experiments were performed in 250 mL flasks to optimize carbon, nitrogen and salts contents in production medium, also comparing different carbon sources and mixtures. The production was then studied in a 30 liter fermenter running for 36 hours. The preliminary studies showed that barley hydrolysate gave the best result 2,4% in bioethanol concentration during the performed fermentations, and saccharose was the best substrate in shake flask fermentations with a 9,6% bioethanol concentration. (orig.)

  18. The activated sludge metabolic characteristics changing sole carbon source from readily biodegradable acetate to toxic phenol.

    Science.gov (United States)

    Wu, Changyong; Zhou, Yuexi; Song, Jiamei

    2016-01-01

    A sequencing batch reactor was used to investigate the effect of carbon sources on the metabolism of activated sludge. Acetate and phenol, with the chemical oxygen demand (COD) of 330-350 mg L(-1), was used as the carbon source in Periods I and II, respectively. Acetate decreased in the initial 120 min with the intracellular storage materials (XSTO), extracellular polymeric substances (EPS), and the soluble microbial products (SMP) accumulating to 131.0 mg L(-1), 347.5 mg L(-1), and 35.5 mg L(-1), respectively. Then, XSTO and EPS decreased to 124.5 mg L(-1) and 340.0 mg L(-1), respectively, in the following 120 min. When acetate was replaced by phenol, it could not be used at the beginning due to its toxicity. The XSTO decreased from 142 mg L(-1) to 54.6 mg L(-1) during the aeration period. The EPS had a significant increase, with the highest value of 618.1 mg L(-1), which then decreased to 245.6 mg L(-1) at 240 min. The phenol was gradually degraded with the acclimation and it can be fully degraded 18 d later. Meanwhile, the usage ratio of the internal carbon source decreased. The effluent SMP in Period II was 1.7 times that in Period I. PMID:27191552

  19. Positive effect of reduced aeration rate on growth and stereospecificity of DL-malic acid consumption by Azospirillum brasilense: improving the shelf life of a liquid inoculant formulation.

    Science.gov (United States)

    Carrasco-Espinosa, Karen; García-Cabrera, Ramsés I; Bedoya-López, Andrea; Trujillo-Roldán, Mauricio A; Valdez-Cruz, Norma A

    2015-02-10

    Azospirillum brasilense has significance as a growth promoter in plants of commercial interest. Two industrial native strains (Start and Calf), used as a part of an inoculant formulation in Mexico during the last 15 years, were incubated in laboratory-scale pneumatic bioreactors at different aeration rates. In both strains, the positive effect of decreased aeration was observed. At the lowest (0.1 vvm, air volume/liquid volume×minute), the highest biomass were obtained for Calf (7.8 × 10(10)CFU/ml), and Start (2.9 × 10(9)CFU/ml). These were higher in one magnitude order compared to cultures carried out at 0.5 vvm, and two compared to those at 1.0 vvm. At lower aeration, both stereoisomeric forms of malic acid were consumed, but at higher aeration, just L-malate was consumed. A reduction in aeration allows an increase of the shelf life and the microorganism saved higher concentrations of polyhydroxybutyrate. The selected fermentation conditions are closely related to those prevalent in large-scale bioreactors and offer the possibility of achieving high biomass titles with high shelf life at a reduced costs, due to the complete use of a carbon source at low aeration of a low cost raw material as DL-malic acid mixture in comparison with the L-malic acid stereoisomer. PMID:25556026

  20. Estimate of denitrifying microbiota in tertiary sewage treatment and kinetics of the denitrification process using different sources of carbon

    Directory of Open Access Journals (Sweden)

    Marchetto Margarida

    2003-01-01

    Full Text Available A study of the kinetics of denitrification was carried out in the laboratory based on the quantification of N2O, the final product of the activity of denitrifying microorganisms, when the enzymatic reduction of N2O to N2 was blocked by acetylene. Concentrated mixed liquor (sludge from a reactor with intermittent aeration used for sewage treatment was used as the inoculum, while methanol, acetic acid, glucose, effluent sewage from an anaerobic fluidized bed reactor and synthetic substrate simulating domestic sewage were used as carbon sources. The mean concentration of nitrate was 20 mg/L. Maxima of N2O production and NO3- consumption occurred between 0.5h and 2.0h of incubation using all the carbon sources, which characterized the denitrification process. Acetic acid and methanol were responsible for the highest rates of N2O production. The estimated number of denitrifying microorganisms in the reactor with intermittent aeration, using the MPN technique, varied from 10(9 to 10(10 MPN/g VSS, indicating a high potential for the occurrence of denitrification.

  1. Landfill aeration worldwide: Concepts, indications and findings

    International Nuclear Information System (INIS)

    Highlights: ► Different landfill aeration concepts and accordant application areas are described. ► Examples of full scale projects are provided for Europe, North-America and Asia. ► Major project findings are summarised, including prospects and limitations. ► Inconsistencies between laboratory and full scale results have been elaborated. ► An explanatory approach in connection with the inconsistencies is provided. - Abstract: The creation of sustainable landfills is a fundamental goal in waste management worldwide. In this connection landfill aeration contributes towards an accelerated, controlled and sustainable conversion of conventional anaerobic landfills into a biological stabilized state associated with a minimised emission potential. The technology has been successfully applied to landfills in Europe, North America and Asia, following different strategies depending on the geographical region, the specific legislation and the available financial resources. Furthermore, methodologies for the incorporation of landfill aeration into the carbon trade mechanisms have been developed in recent years. This manuscript gives an overview on existing concepts for landfill aeration; their application ranges and specifications. For all of the described concepts examples from different countries worldwide are provided, including details regarding their potentials and limitations. Some of the most important findings from these aeration projects are summarised and future research needs have been identified. It becomes apparent that there is a great demand for a systematisation of the available results and implications in order to further develop and optimise this very promising technology. The IWWG (International Waste Working Group) Task Group “Landfill Aeration” contributes towards the achievement of this goal.

  2. CFD study to determine the optimal configuration of aerators in a full-scale waste stabilization pond.

    Science.gov (United States)

    Alvarado, Andres; Vesvikar, Mehul; Cisneros, Juan F; Maere, Thomas; Goethals, Peter; Nopens, Ingmar

    2013-09-01

    Aerated lagoons (ALs) are important variants of the pond wastewater treatment technology that have not received much attention in the literature. The hydraulic behaviour of ALs and especially the Facultative aerated lagoons (FALs) is very complex since the aeration in these systems is designed for oxygen transfer but not necessarily to create complete mixing. In this work, the energy expenditure of the aerators was studied by means of a scenario analysis. 3D CFD models (one phase and multiphase) of a 3 ha FAL in a waste stabilization pond system in Cuenca (Ecuador) were built for different configurations of aerators. The thrust produced by the aerators was modelled by an external momentum source applied as velocity vectors into the pond fluid. The predictions of a single phase model were in satisfactory agreement with experimental results. Subsequently, a scenario analysis assessing several aeration schemes with different numbers of aerators in operation were tested with respect to velocity profiles and residence time distribution (RTD) curves. This analysis showed that the aeration scheme with all 10 aerators switched on produces a similar hydraulic behaviour compared to using only 6 or 8 aerators. The current operational schemes comprise of switching off some aerators during the peak hours of the day and operating all 10 aerators during night. This current practice could be economically replaced by continuously operating 4 or 6 aerators without significantly affecting the overall mixing. Furthermore, a continuous mixing regime minimises the sediment oxygen demand enhancing the oxygen levels in the pond. PMID:23764602

  3. [Optimization Study on the Nitrogen and Phosphorus Removal of Modified Two- sludge System Under the Condition of Low Carbon Source].

    Science.gov (United States)

    Yang, Wei-qiang; Wang, Dong-bo; Li, Xiao-ming; Yang, Qi; Xu, Qiu-xiang; Zhang, Zhi-bei; Li, Zhi-jun; Xiang, Hai-hong; Wang, Ya-li; Sun, Jian

    2016-04-15

    This paper explored the method of resolving insufficient carbon source in urban sewage by comparing and analyzing denitrification and phosphorus removal (NPR) effect between modified two-sludge system and traditional anaerobic-aerobic-anoxic process under the condition of low carbon source wastewater. The modified two-sludge system was the experimental reactor, which was optimized by adding two stages of micro-aeration (aeration rate 0.5 L · mm⁻¹) in the anoxic period of the original two-sludge system, and multi-stage anaerobic-aerobic-anoxic SBR was the control reactor. When the influent COD, ammonia nitrogen, SOP concentration were respectively 200, 35, 10 mg · L⁻¹, the NPR effect of the experimental reactor was hetter than that of thecontrol reactor with the removal efficiency of TN being 94.8% vs 60.9%, and TP removal being 96.5% vs 75%, respectively. The effluent SOP, ammonia, TN concentration of the experimental reactor were 0.35, 0.50, 1.82 mg · L⁻¹, respectively, which could fully meet the first class of A standard of the Pollutants Emission Standard of Urban Wastewater Treatment Firm (GB 18918-2002). Using the optimized treatment process, the largest amounts of nitrogen and phosphorus removal per unit carbon source (as COD) were 0.17 g · g⁻¹ and 0.048 g · g⁻¹ respectively, which could furthest solve the lower carbon concentration in current municipal wastewater. PMID:27548974

  4. Double-walled carbon nanotubes synthesized using carbon black as the dot carbon source

    Science.gov (United States)

    Chen, Zhi-Gang; Li, Feng; Ren, Wen-Cai; Cong, Hongtao; Liu, Chang; Qing Lu, Gao; Cheng, Hui-Ming

    2006-07-01

    Double-walled carbon nanotubes (DWNTs) were synthesized used carbon black as the dot carbon source by a semi-continuous hydrogen arc discharge process. High-resolution transmission electron microscopy (HRTEM) observations revealed that most of the tubes were DWNTs with outer and inner diameters in the range of 2.67-4 nm and 1.96-3.21 nm, respectively. Most of the DWNTs were in a bundle form of about 10-30 nm in diameter with high purity (about 70%) from thermal gravimetric analysis (TGA), resonant laser Raman spectroscopy, scanning electron microscopy (SEM) and TEM characterizations. It was found that carbon black as the dot carbon source could be easy controlled to synthesize one type of nanotube. A simple process combining oxidation and acid treatment to purify the DWNT bundles was used without damaging the bundles. The structure of carbon black, as the key element for influencing purity, bundle formation and purification of DWNTs, is discussed.

  5. Bioreactor tests preliminary to landfill in situ aeration: A case study

    International Nuclear Information System (INIS)

    Highlights: ► Carbon and nitrogen mass balances in aerated landfill simulation reactors. ► Waste stabilization in aerated landfill simulation reactors. ► Effect of temperature on biodegradation processes in aerated landfills. - Abstract: Lab scale tests in bioreactor were carried out in the framework of the characterization studies of a landfill where in situ aeration (possibly followed by landfill mining) had been proposed as part of the novel waste management strategy in a region in northern Italy. The tests were run to monitor the effects produced by aerobic conditions at different temperatures on waste sampled at different depths in the landfill, with focus on the carbon and nitrogen conversion during aeration. Temperatures ranging from 35 to 45 °C were chosen, in order to evaluate possible inhibition of biodegradation processes (namely nitrification) at 45 °C in the landfill. The results obtained showed positive effects of the aeration on leachate quality and a significant reduction of waste biodegradability. Although a delay of biodegradation processes was observed in the reactor run at 45 °C, biodegradation rates increased after 2 months of aeration, providing very low values of the relevant parameters (as in the other aerated reactors) by the end of the study. Mass balances were carried out for TOC and N-NH4+; the findings obtained were encouraging and provided evidence of the effectiveness of carbon and nitrogen conversion processes in the aerated landfill simulation reactors

  6. Bioreactor tests preliminary to landfill in situ aeration: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Raga, Roberto, E-mail: roberto.raga@unipd.it [ICEA Department, University of Padova. Via Marzolo, 9, 35131 Padova (Italy); Cossu, Raffaello [ICEA Department, University of Padova. Via Marzolo, 9, 35131 Padova (Italy)

    2013-04-15

    Highlights: ► Carbon and nitrogen mass balances in aerated landfill simulation reactors. ► Waste stabilization in aerated landfill simulation reactors. ► Effect of temperature on biodegradation processes in aerated landfills. - Abstract: Lab scale tests in bioreactor were carried out in the framework of the characterization studies of a landfill where in situ aeration (possibly followed by landfill mining) had been proposed as part of the novel waste management strategy in a region in northern Italy. The tests were run to monitor the effects produced by aerobic conditions at different temperatures on waste sampled at different depths in the landfill, with focus on the carbon and nitrogen conversion during aeration. Temperatures ranging from 35 to 45 °C were chosen, in order to evaluate possible inhibition of biodegradation processes (namely nitrification) at 45 °C in the landfill. The results obtained showed positive effects of the aeration on leachate quality and a significant reduction of waste biodegradability. Although a delay of biodegradation processes was observed in the reactor run at 45 °C, biodegradation rates increased after 2 months of aeration, providing very low values of the relevant parameters (as in the other aerated reactors) by the end of the study. Mass balances were carried out for TOC and N-NH{sub 4}{sup +}; the findings obtained were encouraging and provided evidence of the effectiveness of carbon and nitrogen conversion processes in the aerated landfill simulation reactors.

  7. Enhanced biological phosphorus removal with different carbon sources.

    Science.gov (United States)

    Shen, Nan; Zhou, Yan

    2016-06-01

    Enhanced biological phosphorus removal (EBPR) process is one of the most economical and sustainable methods for phosphorus removal from wastewater. However, the performance of EBPR can be affected by available carbon sources types in the wastewater that may induce different functional microbial communities in the process. Glycogen accumulating organisms (GAOs) and polyphosphate accumulating organisms (PAOs) are commonly found by coexisting in the EBPR process. Predominance of GAO population may lead to EBPR failure due to the competition on carbon source with PAO without contributing phosphorus removal. Carbon sources indeed play an important role in alteration of PAOs and GAOs in EBPR processes. Various types of carbon sources have been investigated for EBPR performance. Certain carbon sources tend to enrich specific groups of GAOs and/or PAOs. This review summarizes the types of carbon sources applied in EBPR systems and highlights the roles of these carbon sources in PAO and GAO competition. Both single (e.g., acetate, propionate, glucose, ethanol, and amino acid) and complex carbon sources (e.g., yeast extract, peptone, and mixed carbon sources) are discussed in this review. Meanwhile, the environmental friendly and economical carbon sources that are derived from waste materials, such as crude glycerol and wasted sludge, are also discussed and compared. PMID:27087523

  8. Mesoscale inversion of carbon sources and sinks

    International Nuclear Information System (INIS)

    Inverse methods at large scales are used to infer the spatial variability of carbon sources and sinks over the continents but their uncertainties remain large. Atmospheric concentrations integrate the surface flux variability but atmospheric transport models at low resolution are not able to simulate properly the local atmospheric dynamics at the measurement sites. However, the inverse estimates are more representative of the large spatial heterogeneity of the ecosystems compared to direct flux measurements. Top-down and bottom-up methods that aim at quantifying the carbon exchanges between the surface and the atmosphere correspond to different scales and are not easily comparable. During this phD, a mesoscale inverse system was developed to correct carbon fluxes at 8 km resolution. The high resolution transport model MesoNH was used to simulate accurately the variability of the atmospheric concentrations, which allowed us to reduce the uncertainty of the retrieved fluxes. All the measurements used here were observed during the intensive regional campaign CERES of May and June 2005, during which several instrumented towers measured CO2 concentrations and fluxes in the South West of France. Airborne measurements allowed us to observe concentrations at high altitude but also CO2 surface fluxes over large parts of the domain. First, the capacity of the inverse system to correct the CO2 fluxes was estimated using pseudo-data experiments. The largest fraction of the concentration variability was attributed to regional surface fluxes over an area of about 300 km around the site locations depending on the meteorological conditions. Second, an ensemble of simulations allowed us to define the spatial and temporal structures of the transport errors. Finally, the inverse fluxes at 8 km resolution were compared to direct flux measurements. The inverse system has been validated in space and time and showed an improvement of the first guess fluxes from a vegetation model

  9. Generating CO2-credits through landfill in situ aeration

    International Nuclear Information System (INIS)

    Landfills are some of the major anthropogenic sources of methane emissions worldwide. The installation and operation of gas extraction systems for many landfills in Europe and the US, often including technical installations for energy recovery, significantly reduced these emissions during the last decades. Residual landfill gas, however, is still continuously produced after the energy recovery became economically unattractive, thus resulting in ongoing methane emissions for many years. By landfill in situ aeration these methane emissions can be widely avoided both, during the aeration process as well as in the subsequent aftercare period. Based on model calculations and online monitoring data the amount of avoided CO2-eq. can be determined. For an in situ aerated landfill in northern Germany, acting as a case study, 83-95% (depending on the kind and quality of top cover) of the greenhouse gas emission potential could be reduced under strictly controlled conditions. Recently the United Nations Framework Convention on Climate Change (UNFCCC) has approved a new methodology on the 'Avoidance of landfill gas emissions by in situ aeration of landfills' (). Based on this methodology landfill aeration projects might be considered for generation of Certified Emission Reductions (CERs) in the course of CDM projects. This paper contributes towards an evaluation of the potential of landfill aeration for methane emissions reduction.

  10. Deflector plants turbine aeration

    International Nuclear Information System (INIS)

    Water quality requirements have become a focal point in recent re-licensing of hydroelectric projects. The Federal Energy Regulatory Commission has significantly increased the relevance of license conditions to insure that turbine discharges meet state or other specific criteria for dissolved oxygen (D.O.). Due to naturally occurring depletion of D.O. at increased depths in large reservoirs, water withdrawn from this strata may result in unacceptably low levels of D.O. Different researchers have evaluated various methods of improving D.O. content in hydro turbine discharges, including; diffusers, weirs, oxygen injection, and variations of turbine venting. The authors describe an approach called deflector plate turbine aeration. This computer based, engineered approach allows systems to be evaluated, designed, and installed with predictable performance and costs. Many experts in this field now agree that, to the extent practical, turbine venting offers the most dependable, maintenance free, and cost effective solution to the low D.O. problem. The approach presented in this paper has resulted in proven results

  11. Source Molecular Effect on Amorphous Carbon Film Deposition

    OpenAIRE

    Kawazoe, Hiroki; Inayoshi, Takanori; Shinohara, Masanori; Matsuda, Yoshinobu; Fujiyama, Hiroshi; Nitta, Yuki; Nakatani, Tatsuyuki

    2009-01-01

    We investigated deposition process of amorphous carbon films using acetylene and methane as a source molecule, by using infrared spectroscopy in multiple internal reflection geometry (MIR-IRAS). We found that deposited film structures were different due to source molecules.

  12. Monitoring transitory profiles of leachate humic substances in landfill aeration reactors in mesophilic and thermophilic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Huanhuan [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 (Singapore); School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Yin, Ke; Ge, Liya; Giannis, Apostolos [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 (Singapore); Chuan, Valerie W.L. [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Wang, Jing-Yuan, E-mail: JYWANG@ntu.edu.sg [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 (Singapore); School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore)

    2015-04-28

    Highlights: • Polymerization and condensation of humic substances (HS) were enhanced by aeration. • Carboxylic group was enriched in HS by aeration presenting improved hydrophilicity. • Mobility of humic acid, as a result was enhanced by aeration especially in young landfill. • Waste age plays an important role in leachate management during aeration. - Abstract: The presence of humic substances (HS) in landfill leachate is of great interest because of their structural stability and potential toxicity. This study examined the effects of temperature and waste age on the transformation of HS during in situ aeration of bioreactor landfills. By establishing aerobic conditions, dissolved organic carbon (DOC) rapidly accumulated in the bioreactor leachate. Fractional analysis showed that the elevated concentration of humic acids (HAs) was primarily responsible for the increment of leachate strength. Further structural characterization indicated that the molecular weight (MW) and aromacity of HS were enhanced by aeration in conjunction with thermophilic temperature. Interestingly, elevation of HAs concentration was not observed in the aeration reactor with a prolonged waste age, as the mobility of HAs was lowered by the high MW derived from extended waste age. Based on these results, aeration may be more favorable in aged landfills, since dissolution of HAs could be minimized by the evolution to larger MW compared to young landfills. Moreover, increased operation temperature during aeration likely offers benefits for the rapid maturation of HS.

  13. Monitoring transitory profiles of leachate humic substances in landfill aeration reactors in mesophilic and thermophilic conditions

    International Nuclear Information System (INIS)

    Highlights: • Polymerization and condensation of humic substances (HS) were enhanced by aeration. • Carboxylic group was enriched in HS by aeration presenting improved hydrophilicity. • Mobility of humic acid, as a result was enhanced by aeration especially in young landfill. • Waste age plays an important role in leachate management during aeration. - Abstract: The presence of humic substances (HS) in landfill leachate is of great interest because of their structural stability and potential toxicity. This study examined the effects of temperature and waste age on the transformation of HS during in situ aeration of bioreactor landfills. By establishing aerobic conditions, dissolved organic carbon (DOC) rapidly accumulated in the bioreactor leachate. Fractional analysis showed that the elevated concentration of humic acids (HAs) was primarily responsible for the increment of leachate strength. Further structural characterization indicated that the molecular weight (MW) and aromacity of HS were enhanced by aeration in conjunction with thermophilic temperature. Interestingly, elevation of HAs concentration was not observed in the aeration reactor with a prolonged waste age, as the mobility of HAs was lowered by the high MW derived from extended waste age. Based on these results, aeration may be more favorable in aged landfills, since dissolution of HAs could be minimized by the evolution to larger MW compared to young landfills. Moreover, increased operation temperature during aeration likely offers benefits for the rapid maturation of HS

  14. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    WU JianHua; RUAN ShiPing

    2008-01-01

    It is proved that air entrainment is one of the efficient measures dealing with cavitation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator, which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emergence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects, of both model and prototype, on the basis of error theory. A method to calculate the cavity length below aerators was suggested, which considers overall effects of the above mentioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.

  15. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    It is proved that air entrainment is one of the efficient measures dealing with cavi-tation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator,which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emer-gence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects,of both model and prototype,on the basis of error theory. A method to calculate the cavity length be-low aerators was suggested,which considers overall effects of the above men-tioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.

  16. Source attribution of black carbon in Arctic snow.

    Science.gov (United States)

    Hegg, Dean A; Warren, Stephen G; Grenfell, Thomas C; Doherty, Sarah J; Larson, Timothy V; Clarke, Antony D

    2009-06-01

    Snow samples obtained at 36 sites in Alaska, Canada, Greenland, Russia, and the Arctic Ocean in early 2007 were analyzed for light-absorbing aerosol concentration together with a suite of associated chemical species. The light absorption data, interpreted as black carbon concentrations, and other chemical data were input into the EPA PMF 1.1 receptor model to explore the sources for black carbon in the snow. The analysis found four factors or sources: two distinct biomass burning sources, a pollution source, and a marine source. The first three of these were responsible for essentially all of the black carbon, with the two biomass sources (encompassing both open and closed combustion) together accounting for >90% of the black carbon. PMID:19569324

  17. Modulation of Candida albicans Biofilm by Different Carbon Sources.

    Science.gov (United States)

    Pemmaraju, Suma C; Pruthi, Parul A; Prasad, R; Pruthi, Vikas

    2016-06-01

    In the present investigation, the role of carbon sources (glucose, lactate, sucrose, and arabinose) on Candida albicans biofilm development and virulence factors was studied on polystyrene microtiter plates. Besides this, structural changes in cell wall component β-glucan in presence of different carbon sources have also been highlighted. Biofilm formation was analyzed by XTT (2,3-bis[2-Methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay. Glucose-grown cells exhibited the highest metabolic activity during adhesion among all carbon sources tested (p albicans biofilm development and modulate virulence factors and structural organization of cell wall component β-glucan. PMID:26899861

  18. Growth of graphene films from non-gaseous carbon sources

    Science.gov (United States)

    Tour, James; Sun, Zhengzong; Yan, Zheng; Ruan, Gedeng; Peng, Zhiwei

    2015-08-04

    In various embodiments, the present disclosure provides methods of forming graphene films by: (1) depositing a non-gaseous carbon source onto a catalyst surface; (2) exposing the non-gaseous carbon source to at least one gas with a flow rate; and (3) initiating the conversion of the non-gaseous carbon source to the graphene film, where the thickness of the graphene film is controllable by the gas flow rate. Additional embodiments of the present disclosure pertain to graphene films made in accordance with the methods of the present disclosure.

  19. Shunting arc plasma source for pure carbon ion beama)

    Science.gov (United States)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm2 at the peak of the pulse.

  20. Shunting arc plasma source for pure carbon ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y. [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2012-02-15

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm{sup 2} at the peak of the pulse.

  1. Shunting arc plasma source for pure carbon ion beam.

    Science.gov (United States)

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse. PMID:22380206

  2. Aspects concerning the quality of aeration for environmental friendly turbines

    Science.gov (United States)

    Bunea, F.; Houde, S.; Ciocan, G. D.; Oprina, G.; Baran, G.; Pincovschi, I.

    2010-08-01

    The hydro renewable energy provides a reliable power source; it does not pollute the air or land but affects the aquatic habitat due to low dissolved oxygen (DO) level in the water discharged from turbines. Hydro-turbines intake generally withdraws water from the bottom layer of the reservoirs with low DO level. In the different methods used for improving DO downstream the hydropower plants the volume of air is considered to be the main parameter of the injection. The energetic consumption is affected, in terms of loss of turbine efficiency due to air injection. The authors propose a study to show the importance of the quality of air injection, meaning bubble size, pressure loss on the aeration device etc. Different types of fine bubble aeration systems have been tested and compared. The capacity to predict the aeration by numerical simulation is analysed.

  3. Aspects concerning the quality of aeration for environmental friendly turbines

    International Nuclear Information System (INIS)

    The hydro renewable energy provides a reliable power source; it does not pollute the air or land but affects the aquatic habitat due to low dissolved oxygen (DO) level in the water discharged from turbines. Hydro-turbines intake generally withdraws water from the bottom layer of the reservoirs with low DO level. In the different methods used for improving DO downstream the hydropower plants the volume of air is considered to be the main parameter of the injection. The energetic consumption is affected, in terms of loss of turbine efficiency due to air injection. The authors propose a study to show the importance of the quality of air injection, meaning bubble size, pressure loss on the aeration device etc. Different types of fine bubble aeration systems have been tested and compared. The capacity to predict the aeration by numerical simulation is analysed.

  4. The Variation Characteristic of Sulfides and VOSc in a Source Water Reservoir and Its Control Using a Water-Lifting Aerator

    OpenAIRE

    Shi, Jian-Chao; Huang, Ting-Lin; Wen, Gang; Liu, Fei; Qiu, Xiao-Peng; Wang, Bao-Shan

    2016-01-01

    Sulfides and volatile organic sulfur compounds (VOSc) in water are not only malodorous but also toxic to humans and aquatic organisms. They cause serious deterioration in the ecological environment and pollute drinking water sources. In the present study, a source water reservoir—Zhoucun Reservoir in East China—was selected as the study site. Through a combination of field monitoring and in situ release experiments of sulfides, the characteristics of seasonal variation and distribution of sul...

  5. Who's working on fishpond aeration

    OpenAIRE

    Kibria, S.

    1991-01-01

    The findings are provided of a literature search conducted on the topic of fishpond aeration, using ASFA for the period 1971-1990 and the ICLARM library and professional staff collection. A total of 97 articles were found. The type of publication is indicated and details given of some of the recent publications and some research institutions working in this field.

  6. Non-autoclaved aerated concrete with mineral additives

    Science.gov (United States)

    Il'ina, L. V.; Rakov, M. A.

    2016-01-01

    We investigated the effect of joint grinding of Portland cement clinker, silica and carbonate components and mineral additives to specific surface of 280 - 300 m2/kg on the properties (strength, average density and thermal conductivity) of non-autoclaved aerated concrete, and the porosity of the hardened cement paste produced from Portland cement clinker with mineral additives. The joint grinding of the Portland cement clinker with silica and carbonate components and mineral additives reduces the energy consumption of non-autoclaved aerated concrete production. The efficiency of mineral additives (diopside, wollastonite) is due to the closeness the composition, the type of chemical bonds, physical and chemical characteristics (specific enthalpy of formation, specific entropy) to anhydrous clinker minerals and their hydration products. Considering the influence of these additions on hydration of clinker minerals and formation of hardened cement paste structure, dispersed wollastonite and diopside should be used as mineral additives. The hardness and, consequently, the elastic modulus of diopside are higher than that of hardened cement paste. As a result, there is a redistribution of stresses in the hardened cement paste interporous partitions and hardening, both the partitions and aerated concrete on the whole. The mineral additives introduction allowed to obtain the non-autoclaved aerated concrete with average density 580 kg/m3, compressive strength of 3.3 MPa and thermal conductivity of 0.131 W/(m.°C).

  7. Facilitating Conceptual Understanding of Gas-Liquid Mass Transfer Coefficient through a Simple Experiment Involving Dissolution of Carbon Dioxide in Water in a Surface Aeration Reactor

    Science.gov (United States)

    Utgikar, Vivek P.; MacPherson, David

    2016-01-01

    Students in the undergraduate "transport phenomena" courses typically have a greater difficulty in understanding the theoretical concepts underlying the mass transport phenomena as compared to the concepts of momentum and energy transport. An experiment based on dissolution of carbon dioxide in water was added to the course syllabus to…

  8. Glucose Metabolism in Lactococcus lactis MG1363 under Different Aeration Conditions: Requirement of Acetate To Sustain Growth under Microaerobic Conditions

    OpenAIRE

    Nordkvist, Mikkel; Jensen, Niels Bang Siemsen; Villadsen, John

    2003-01-01

    Lactococcus lactis subsp. lactis MG1363 was grown in batch cultures on a defined medium with glucose as the energy source under different aeration conditions, namely, anaerobic conditions, aerobic conditions, and microaerobic conditions with a dissolved oxygen tension of 5% (when saturation with air was used as the reference). The maximum specific growth rate was high (0.78 to 0.91 h−1) under all aeration conditions but decreased with increasing aeration, and more than 90% of the glucose was ...

  9. A Novel Aeration Method for the Preparation of Algae (Dunaliella Salina) Biomass for Biofuel Production.

    OpenAIRE

    U.O. Enwereuzoh; G.N. Onyeagoro

    2014-01-01

    Preparation of algae (Dunaliela Salina) biomass in ammonia (NH4 + ) and nitrate (NO3 - ) growth media for biofuel production was investigated, with special attention on the elimination of inhibitory oxygen that adversely affects algae growth. A novel aeration method based on high and efficient transfer of carbon dioxide (CO2) required to stabilize the CO2 of the algae growth medium in a short time was adopted for the elimination of the inhibitory oxygen. The novel aeration method was found...

  10. Aeration of the teuftal landfill: Field scale concept and lab scale simulation.

    Science.gov (United States)

    Ritzkowski, Marco; Walker, Beat; Kuchta, Kerstin; Raga, Roberto; Stegmann, Rainer

    2016-09-01

    Long lasting post-closure care (PCC) is often the major financial burden for operators of municipal solid waste (MSW) landfills. Beside costs for the installation and maintenance of technical equipment and barriers, in particular long term treatment of leachate and landfill gas has to be paid from capital surplus. Estimations based on laboratory experiments project time periods of many decades until leachate quality allows for direct discharge (i.e. no need for further purification). Projections based on leachate samples derived from the last 37years for 35 German landfills confirm these assumption. Moreover, the data illustrate that in particular ammonium nitrogen concentrations are likely to fall below limit values only after a period of 300years. In order to avoid long lasting PCC the operator of Teuftal landfill, located in the Swiss canton Bern, decided to biologically stabilize the landfill by means of a combined in situ aeration and moisturization approach. In December 2014 the aeration started at a landfill section containing approximately 30% of the total landfill volume. From summer 2016 onwards the remaining part of the landfill will be aerated. Landfill aeration through horizontal gas and leachate drains is carried out for the first time in field scale in Europe. The technical concept is described in the paper. Parallel to field scale aeration, investigations for the carbon and nitrogen turnover are carried out by means of both simulated aerated landfills and simulated anaerobic landfills. The results presented in this paper demonstrate that aeration is capable to enhance, both carbon mobilization and discharge via the gas phase. This effect comes along with a significant increase in bio-stabilization of the waste organic fraction, which positively affects the landfill emission behavior in the long run. In terms of leachate pollution reduction it could be demonstrated that the organic load decrease fast and widely independent of the adjusted aeration

  11. Determination methodology of biomass and Pac at aeration unit in Pact process

    International Nuclear Information System (INIS)

    In this research by using two pilot scale systems of activated sludge and powdered activated carbon technology, the soluble organic load removal efficiency was evaluated, for a synthetic wastewater with mono-ethylen glyco le as carbon source. Also, the variations of biomass and powdered activated carbon in each reactor were studied and the relative accuracy of differential ignition method for determining the amount of biomass and powdered activated carbon (combined in aeration unite of the powdered activated carbon pilot) was investigated. Results showed that the method may be used for the determination of powdered activated carbon and biomass volatility at 400deg C and 550deg C respectively, with acceptable accuracy. Comparison between the results of this study and some other recent studies, show that there is no significant differences between them at 95% confidence. Furthermore, the results of this study indicated that there was little difference in carbon to biomass ration which supports the concept that solid residence time and the amount of wastage sludge can be determined with total suspended solids analysis and there is no necessity for biomass determination

  12. Glucose metabolism in Lactococcus lactis MG1363 under different aeration conditions: Requirement of acetate to sustain growth under microaerobic conditions

    DEFF Research Database (Denmark)

    Nordkvist, Mikkel; Jensen, N.B.S.; Villadsen, John

    2003-01-01

    Lactococcus lactis subsp. lactis MG1363 was grown in batch cultures on a defined medium with glucose as the energy source under different aeration conditions, namely, anaerobic conditions, aerobic conditions, and microaerobic conditions with a dissolved oxygen tension of 5% (when saturation with...... air was used as the reference). The maximum specific growth rate was high (0.78 to 0.91 h(-1)) under all aeration conditions but decreased with increasing aeration, and more than 90% of the glucose was converted to lactate. However, a shift in by-product formation was observed. Increasing aeration...

  13. Research on the Effectiveness of Aerators

    Directory of Open Access Journals (Sweden)

    Vytenis Leonavičius

    2013-02-01

    Full Text Available In biological wastewater treatment plants, the right selection of an aerator is one of the most important elements. The choice of the aerator must take in account its performance – dissolved oxygen content per unit of energy consumed, oxidative capacity and supply of the required amount of air so that the required concentration of oxygen is saturated properly. The experiments have been conducted carefully examining the efficiency of the selected deep–cavitation aerator operating without the aerator tip or with attached two and three–blade tips. The performed investigation included air dispersion methods of opposite ejecting for determining air flow, flow pressure and dependence of vibration on different placement of the aerator under varying positions of corners. It has been established that compared to air ejecting flow, changes in pressure and vibration are most significantly influenced by a deep–cavitation aerator having a three–blade tip.Article in Lithuanian

  14. Research on the Effectiveness of Aerators

    Directory of Open Access Journals (Sweden)

    Vytenis Leonavičius

    2012-12-01

    Full Text Available In biological wastewater treatment plants, the right selection of an aerator is one of the most important elements. The choice of the aerator must take in account its performance – dissolved oxygen content per unit of energy consumed, oxidative capacity and supply of the required amount of air so that the required concentration of oxygen is saturated properly. The experiments have been conducted carefully examining the efficiency of the selected deep–cavitation aerator operating without the aerator tip or with attached two and three–blade tips. The performed investigation included air dispersion methods of opposite ejecting for determining air flow, flow pressure and dependence of vibration on different placement of the aerator under varying positions of corners. It has been established that compared to air ejecting flow, changes in pressure and vibration are most significantly influenced by a deep–cavitation aerator having a three–blade tip.Article in Lithuanian

  15. Intermittent Aeration in Biological Treatment of Wastewater

    Directory of Open Access Journals (Sweden)

    H. Doan

    2009-01-01

    Full Text Available Problem statement: E-coating process is widely used to provide a protective coating layer on metal parts in the automotive and metal finishing industry. The wastewater from the coating process contains organic compounds that are used in the cleaning, pretreatment and coating steps. Organic pollutants can be removed biologically. In the aerobic biological treatment, water aeration accounts for a significant portion of the total operating cost of the treatment process. Intermittent aeration is thus of benefit since it would reduce the energy consumption in the wastewater treatment. In the present study, wastewater from an electro-coating process was treated biologically using a packed column as an aerator where the wastewater was aerated by a countercurrent air flow. The objective was to obtain an optimum aeration cycle. Approach: Intermittent aeration time was varied at different preset cycles. An operational optimum of the aeration time (or air-water contacting time in the column was determined from the BOD5 removal after a certain treatment period. For continuous aeration of the wastewater, the air-liquid contacting time in the column was 52 min for 24 h of treatment. A unit energy consumption for pumping liquid and air, which was defined as the energy consumption per percent BOD5 removed, was used as a criterion to determine the optimum contacting time. Results: Optimum air-liquid contacting times were found to be about 38, 26 and 22 min for the treatment times of 24, 48 and 72 h, consecutively. This indicates that 27-58% saving on the unit energy consumption can be achieved using intermittent aeration of the wastewater. On the basis of the overall BOD5 removal, 17% and 23% savings in energy were observed with the intermittent aeration as compared to the continuous aeration of the wastewater for 48 and 72 h. Conclusion: The results obtained indicate that an appropriate intermittent aeration cycle can bring about a substantial energy saving

  16. Simultaneous ammonia and nitrate removal in an airlift reactor using poly(butylene succinate) as carbon source and biofilm carrier.

    Science.gov (United States)

    Ruan, Yun-Jie; Deng, Ya-Le; Guo, Xi-Shan; Timmons, Michael B; Lu, Hui-Feng; Han, Zhi-Ying; Ye, Zhang-Ying; Shi, Ming-Ming; Zhu, Song-Ming

    2016-09-01

    In this study, an airlift inner-loop sequencing batch reactor using poly(butylene succinate) as the biofilm carrier and carbon source was operated under an alternant aerobic/anoxic strategy for nitrogen removal in recirculating aquaculture system. The average TAN and nitrate removal rates of 47.35±15.62gNH4-Nm(-3)d(-1) and 0.64±0.14kgNO3-Nm(-3)d(-1) were achieved with no obvious nitrite accumulation (0.70±0.76mg/L) and the dissolved organic carbon in effluents was maintained at 148.38±39.06mg/L. Besides, the activities of dissimilatory nitrate reduction to ammonium and sulfate reduction activities were successfully inhibited. The proteome KEGG analysis illustrated that ammonia might be removed through heterotrophic nitrification, while the activities of nitrate and nitrite reductases were enhanced through aeration treatment. The microbial community analysis revealed that denitrifiers of Azoarcus and Simplicispira occupied the dominate abundance which accounted for the high nitrate removal performance. Overall, this study broadened our understanding of simultaneous nitrification and denitrification using biodegradable material as biofilm carrier. PMID:27343453

  17. ETHANOL PRODUCTION FROM XYLOSE AND WOOD HYDROLYZATE BY MUCOR INDICUS AT DIFFERENT AERATION RATES

    Directory of Open Access Journals (Sweden)

    Ria Millati

    2008-11-01

    Full Text Available The fungus Mucor indicus is able to produce ethanol from xylose as well as dilute-acid lignocellulosic hydrolyzates. The fungus completely assimilated 10 g/L xylose as the sole carbon and energy source within 32 to 65 h at an aeration rate of 0.1 to 1.0 vvm. The highest ethanol yield was 0.16 g/g at 0.1 vvm. Xylitol was formed intermediately with a maximum yield of 0.22 g/g at 0.5 vvm, but disappeared towards the end of experiments. During cultivation in a mixture of xylose and glucose, the fungus did not assimilate xylose as long as glucose was present in the medium. The anaerobic cultivation of the fungus in the hydrolyzate containing 20% xylose and 80% hexoses resulted in no assimilation of xylose but complete consumption of the hexoses in less than 15 h. The ethanol yield was 0.44 g/g. However, the xylose in the hydrolyzate was consumed when the media was aerated at 0.067 to 0.333 vvm. The best ethanol yield was 0.44 g/g at 0.067 vvm. The results of this study suggest that M. indicus hydrolyzate can be first fermented anaerobically for hexose assimilation and subsequently continued under oxygen-limited conditions for xylose fermentation.

  18. Chemoselective Synthesis of Carbamates using CO2 as Carbon Source.

    Science.gov (United States)

    Riemer, Daniel; Hirapara, Pradipbhai; Das, Shoubhik

    2016-08-01

    Synthesis of carbamates directly from amines using CO2 as the carbon source is a straightforward and sustainable approach. Herein, we describe a highly effective and chemoselective methodology for the synthesis of carbamates at room temperature and atmospheric pressure. This methodology can also be applied to protect the amino group in amino acids and peptides, and also to synthesize important pharmaceuticals. PMID:27376902

  19. Growth of carbon nanotube field emitters on single strand carbon fiber: a linear electron source

    International Nuclear Information System (INIS)

    The multi-stage effect has been revisited through growing carbon nanotube field emitters on single strand carbon fiber with a thickness of 11 μm. A prepared linear electron source exhibits a turn-on field as low as 0.4 V μm-1 and an extremely high field enhancement factor of 19 300, when compared with those results from reference nanotube emitters grown on flat silicone wafer; 3.0 V μm-1 and 2500, respectively. In addition, we introduce a novel method to grow nanotubes uniformly around the circumference of carbon fibers by using direct resistive heating on the continuously feeding carbon threads. These results open up not only a new path for synthesizing nanocomposites, but also offer an excellent linear electron source for special applications such as backlight units for liquid crystal displays and multi-array x-ray sources.

  20. Bioreactor tests preliminary to landfill in situ aeration: a case study.

    Science.gov (United States)

    Raga, Roberto; Cossu, Raffaello

    2013-04-01

    Lab scale tests in bioreactor were carried out in the framework of the characterization studies of a landfill where in situ aeration (possibly followed by landfill mining) had been proposed as part of the novel waste management strategy in a region in northern Italy. The tests were run to monitor the effects produced by aerobic conditions at different temperatures on waste sampled at different depths in the landfill, with focus on the carbon and nitrogen conversion during aeration. Temperatures ranging from 35 to 45°C were chosen, in order to evaluate possible inhibition of biodegradation processes (namely nitrification) at 45°C in the landfill. The results obtained showed positive effects of the aeration on leachate quality and a significant reduction of waste biodegradability. Although a delay of biodegradation processes was observed in the reactor run at 45°C, biodegradation rates increased after 2 months of aeration, providing very low values of the relevant parameters (as in the other aerated reactors) by the end of the study. Mass balances were carried out for TOC and NNH4(+); the findings obtained were encouraging and provided evidence of the effectiveness of carbon and nitrogen conversion processes in the aerated landfill simulation reactors. PMID:23274082

  1. COMPUTER AIDED DESIGN OF DIFFUSED AERATION SYSTEMS

    Science.gov (United States)

    CADDAS (Computer Aided Design of Diffused Aeration Systems) is a microcomputer-based program that analyzes the cost and performance of diffused aeration used in activated sludge wastewater treatment systems. The program can analyze both coarse bubble and fine pore diffusers as we...

  2. Penetration height correlations for non-aerated and aerated transverse liquid jets in supersonic cross flow

    Energy Technology Data Exchange (ETDEWEB)

    Ghenai, Chaouki [Florida Atlantic University, Department of Mechanical Engineering, College of Engineering and Computer Science, Boca Raton, FL (United States); Sapmaz, Hayri [Boston Scientific, Miami, FL (United States); Lin, Cheng-Xian [University of Tennessee, Department of Mechanical, Aerospace, and Biomedical Engineering, Knoxville, TN (United States)

    2009-01-15

    Experimental results on the mixing of non-aerated and aerated transverse liquid jet in supersonic cross flow (M=1.5) are presented in this paper. The goal of this study is to investigate the effect of the gas/liquid mass ratio on the penetration and atomization of an aerated liquid jet in high speed cross flow and to develop correlations for the penetration heights. High speed imaging system was used in this study for the visualization of the injection of aerated liquid jet. The results show the effect of jet/cross flow momentum flux ratio, the gas/liquid mass ratio and the Ohnesorge number on the penetration of aerated liquid jet in supersonic cross-flow. New correlations of the spray penetration height for the non-aerated liquid jet (GLR=0) and the net gain in spray penetration height for the aerated liquid jet (GLR>0) are presented. (orig.)

  3. Inductive effect produced by a mixture of carbon source in the production of gibberellic acid by Gibberella fujikuroi.

    Science.gov (United States)

    Rios-Iribe, Erika Y; Flores-Cotera, Luis B; Chávira, Mario M González; González-Alatorre, Guillermo; Escamilla-Silva, Eleazar M

    2011-06-01

    Gibberellic acid has been known since 1954 but its effect on rice still remains very important in the agricultural world. Gibberellic acid (GA3) is the main secondary metabolite produced by the Gibberella fujikuroi fungus. This hormone is of great importance in agriculture and the brewing industry, due to its fast and strong effects at low concentrations (μg) on the processes of growth stimulation, flowering, stem elongation, and germination of seeds, among others. Plant promoters of growth production such as the gibberellins, especially the GA3 are a priority in obtaining better harvests in the agricultural area and by extension, improving the food industry. Three routes to obtaining GA3 have been reported: extraction from plants, chemical synthesis and microbial fermentation. The latter being the most common method used to produce GA3. In this investigation, glucose-corn oil mixture was used as a carbon source on the basis of 40 g of carbon in a 7 L stirred tank bioreactor. A pH of 3.5, 29°C, 600 min(-1) agitation and 1 vvm aeration were maintained and controlled with a biocontroller connected to the bioreactor, throughout the entire culture time. The carbon source mixture affected the fermentation time as well as the production of the GAs. The production of 380 mg GA3L(-1) after 288 h of fermentation was obtained when the glucose-corn oil mixture was employed contrasting the 136 mg GA3L(-1) at 264 h of culture when only glucose was used. PMID:25187149

  4. Photoautotrophic microorganisms as a carbon source for temperate soil invertebrates.

    Science.gov (United States)

    Schmidt, Olaf; Dyckmans, Jens; Schrader, Stefan

    2016-01-01

    We tested experimentally if photoautotrophic microorganisms are a carbon source for invertebrates in temperate soils. We exposed forest or arable soils to a (13)CO2-enriched atmosphere and quantified (13)C assimilation by three common animal groups: earthworms (Oligochaeta), springtails (Hexapoda) and slugs (Gastropoda). Endogeic earthworms (Allolobophora chlorotica) and hemiedaphic springtails (Ceratophysella denticulata) were highly (13)C enriched when incubated under light, deriving up to 3.0 and 17.0%, respectively, of their body carbon from the microbial source in 7 days. Earthworms assimilated more (13)C in undisturbed soil than when the microbial material was mixed into the soil, presumably reflecting selective surface grazing. By contrast, neither adult nor newly hatched terrestrial slugs (Deroceras reticulatum) grazed on algal mats. Non-photosynthetic (13)CO2 fixation in the dark was negligible. We conclude from these preliminary laboratory experiments that, in addition to litter and root-derived carbon from vascular plants, photoautotrophic soil surface microorganisms (cyanobacteria, algae) may be an ecologically important carbon input route for temperate soil animals that are traditionally assigned to the decomposer channel in soil food web models and carbon cycling studies. PMID:26740559

  5. Methane and carbon at equilibrium in source rocks

    OpenAIRE

    Mango, Frank D

    2013-01-01

    Methane in source rocks may not exist exclusively as free gas. It could exist in equilibrium with carbon and higher hydrocarbons: CH4 + C  Hydrocarbon. Three lines of evidence support this possibility. 1) Shales ingest gas in amounts and selectivities consistent with gas-carbon equilibrium. There is a 50% increase in solid hydrocarbon mass when Fayetteville Shale is exposed to methane (450 psi) under moderate conditions (100°C): Rock-Eval S2 (mg g-1) 8.5 = > 12.5. All light hydrocarbons are i...

  6. Carbon Sources for Polyhydroxyalkanoates and an Integrated Biorefinery

    Science.gov (United States)

    Jiang, Guozhan; Hill, David J.; Kowalczuk, Marek; Johnston, Brian; Adamus, Grazyna; Irorere, Victor; Radecka, Iza

    2016-01-01

    Polyhydroxyalkanoates (PHAs) are a group of bioplastics that have a wide range of applications. Extensive progress has been made in our understanding of PHAs’ biosynthesis, and currently, it is possible to engineer bacterial strains to produce PHAs with desired properties. The substrates for the fermentative production of PHAs are primarily derived from food-based carbon sources, raising concerns over the sustainability of their production in terms of their impact on food prices. This paper gives an overview of the current carbon sources used for PHA production and the methods used to transform these sources into fermentable forms. This allows us to identify the opportunities and restraints linked to future sustainable PHA production. Hemicellulose hydrolysates and crude glycerol are identified as two promising carbon sources for a sustainable production of PHAs. Hemicellulose hydrolysates and crude glycerol can be produced on a large scale during various second generation biofuels’ production. An integration of PHA production within a modern biorefinery is therefore proposed to produce biofuels and bioplastics simultaneously. This will create the potential to offset the production cost of biofuels and reduce the overall production cost of PHAs. PMID:27447619

  7. Carbon Sources for Polyhydroxyalkanoates and an Integrated Biorefinery.

    Science.gov (United States)

    Jiang, Guozhan; Hill, David J; Kowalczuk, Marek; Johnston, Brian; Adamus, Grazyna; Irorere, Victor; Radecka, Iza

    2016-01-01

    Polyhydroxyalkanoates (PHAs) are a group of bioplastics that have a wide range of applications. Extensive progress has been made in our understanding of PHAs' biosynthesis, and currently, it is possible to engineer bacterial strains to produce PHAs with desired properties. The substrates for the fermentative production of PHAs are primarily derived from food-based carbon sources, raising concerns over the sustainability of their production in terms of their impact on food prices. This paper gives an overview of the current carbon sources used for PHA production and the methods used to transform these sources into fermentable forms. This allows us to identify the opportunities and restraints linked to future sustainable PHA production. Hemicellulose hydrolysates and crude glycerol are identified as two promising carbon sources for a sustainable production of PHAs. Hemicellulose hydrolysates and crude glycerol can be produced on a large scale during various second generation biofuels' production. An integration of PHA production within a modern biorefinery is therefore proposed to produce biofuels and bioplastics simultaneously. This will create the potential to offset the production cost of biofuels and reduce the overall production cost of PHAs. PMID:27447619

  8. Spatial distribution of carbon sources and sinks in Canada's forests

    International Nuclear Information System (INIS)

    Annual spatial distributions of carbon sources and sinks in Canada's forests at 1 km resolution are computed for the period from 1901 to 1998 using ecosystem models that integrate remote sensing images, gridded climate, soils and forest inventory data. GIS-based fire scar maps for most regions of Canada are used to develop a remote sensing algorithm for mapping and dating forest burned areas in the 25 yr prior to 1998. These mapped and dated burned areas are used in combination with inventory data to produce a complete image of forest stand age in 1998. Empirical NPP age relationships were used to simulate the annual variations of forest growth and carbon balance in 1 km pixels, each treated as a homogeneous forest stand. Annual CO2 flux data from four sites were used for model validation. Averaged over the period 1990-1998, the carbon source and sink map for Canada's forests show the following features: (i) large spatial variations corresponding to the patchiness of recent fire scars and productive forests and (ii) a general south-to-north gradient of decreasing carbon sink strength and increasing source strength. This gradient results mostly from differential effects of temperature increase on growing season length, nutrient mineralization and heterotrophic respiration at different latitudes as well as from uneven nitrogen deposition. The results from the present study are compared with those of two previous studies. The comparison suggests that the overall positive effects of non-disturbance factors (climate, CO2 and nitrogen) outweighed the effects of increased disturbances in the last two decades, making Canada's forests a carbon sink in the 1980s and 1990s. Comparisons of the modeled results with tower-based eddy covariance measurements of net ecosystem exchange at four forest stands indicate that the sink values from the present study may be underestimated

  9. Carbon sources effect on pectinase production from Aspergillus japonicus 586

    Directory of Open Access Journals (Sweden)

    Teixeira Maria F. S.

    2000-01-01

    Full Text Available The effect of different carbon sources on the pectinesterases, endo- and exo-polygalacturonase activities from Aspergillus japonicus 586 was evaluated in liquid media (Manachini solutions supplemented with different substrate concentrations. The culture medium was inoculated with 5.10(6 spores/ml and mantained under agitation (140 rpm, at 30°C, during 122 h. The enzyme evaluation was carried out 24 h after filtration. The crude extract from A. japonicus 586 indicated that the best enzymatic activities were afforded in the presence of 0.5% pectin (pectinesterease, 0.2% pectin and 0.2% glycerol (endopolygalacturonase, and 0.5% pectin associated to 0.5% glucose (exopolygalacturonase. Carbon sources concentration, isolated or associated, significantly affects the pectinesterase, and endo- and exopolygalacturonase activities. Pectin, glucose and saccharose, when added to the culture medium in high concentrations, exhibited a repression effect on all the analyzed enzymes.

  10. Enhancement of Bacillus subtilis Lipopeptide Biosurfactants Production through Optimization of Medium Composition and Adequate Control of Aeration

    Directory of Open Access Journals (Sweden)

    Dhouha Ghribi

    2011-01-01

    Full Text Available Interest in biosurfactants has increased considerably in recent years, as they are potentially used in many commercial applications in petroleum, pharmaceuticals, biomedical, and food processing industries. Since improvement of their production was of great importance to reduce the final coast, cultural conditions were analyzed to optimize biosurfactants production from Bacillus subtilis SPB1 strain. A high yield of biosurfactants was obtained from a culture of B. subtilis using carbohydrate substrate as a carbon source; among carbohydrates, glucose enhanced the best surfactin production. The optimum glucose concentration was 40 g/L. Higher amount of biosurfactants was obtained using 5 g/L of urea as organic nitrogen source and applying C/N ratio of 7 with ammonium chloride as inorganic nitrogen source. The highest amount of biosurfactants was recorded with the addition of 2% kerosene. Moreover, it was shown, using an automated full-controlled 2.6 L fermenter, that aeration of the medium, which affected strongly the growth regulated biosurfactants synthesis by the producing cell. So that, low or high aerations lead to a decrease of biosurfactants synthesis yields. It was found that when using dissolved oxygen saturation of the medium at 30%, biosurfactants production reached 4.92 g/L.

  11. Fluorescently tuned nitrogen-doped carbon dots from carbon source with different content of carboxyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hao; Wang, Yun; Dai, Xiao; Zou, Guifu, E-mail: kqzhang@suda.edu.cn, E-mail: zouguifu@suda.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Gao, Peng; Zhang, Ke-Qin, E-mail: kqzhang@suda.edu.cn, E-mail: zouguifu@suda.edu.cn; Du, Dezhuang [National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123 (China); Guo, Jun [Testing and Analysis Center, Soochow University, Suzhou 215123 (China)

    2015-08-01

    In this study, fluorescent nitrogen-doped carbon dots (NCDs) were tuned via varying the sources with different number of carboxyl groups. Owing to the interaction between amino and carboxyl, more amino groups conjugate the surface of the NCDs by the source with more carboxyl groups. Fluorescent NCDs were tuned via varying the sources with different content of carboxyl groups. Correspondingly, the nitrogen content, fluorescence quantum yields and lifetime of NCDs increases with the content of carboxyl groups from the source. Furthermore, cytotoxicity assay and cell imaging test indicate that the resultant NCDs possess low cytotoxicity and excellent biocompatibility.

  12. Fluorescently tuned nitrogen-doped carbon dots from carbon source with different content of carboxyl groups

    International Nuclear Information System (INIS)

    In this study, fluorescent nitrogen-doped carbon dots (NCDs) were tuned via varying the sources with different number of carboxyl groups. Owing to the interaction between amino and carboxyl, more amino groups conjugate the surface of the NCDs by the source with more carboxyl groups. Fluorescent NCDs were tuned via varying the sources with different content of carboxyl groups. Correspondingly, the nitrogen content, fluorescence quantum yields and lifetime of NCDs increases with the content of carboxyl groups from the source. Furthermore, cytotoxicity assay and cell imaging test indicate that the resultant NCDs possess low cytotoxicity and excellent biocompatibility

  13. Effect of carbon source on the denitrification in constructed wetlands

    Institute of Scientific and Technical Information of China (English)

    LU Songliu; HU Hongying; SUN Yingxue; YANG Jia

    2009-01-01

    The constructed wetlands with different plants in removal of nitrate were investigated.The factors promoting the rates of denitrification including organic carbon, nitrate load, plants in wetlands, pH and water temperature in field were systematically investigated.The results showed that the additional carbon source (glucose) can remarkably improve the nitrate removal ability of the constructed wetland.It demonstrated that the nitrate removal rate can increase from 20% to more than 50% in the summer and from 10% to 30% in the winter, when the nitrate concentration was 30-40 mg/L, the retention time was 24 h and 25 mg/L dissolved organic carbon (DOC) was ploughed into the constructed wetland.However, the nitrite in the constructed wetland accumulated a litter with the supply of the additional carbon source in summer and winter, and it increased from 0.15 to 2 mg/L in the effluent.It was also found that the abilities of plant in adjusting pH and temperature can result in an increase of denitrification in wetlands, and the seasonal change may impact the denitrification.

  14. Effect of Aeration on Seafood Processing Wastewater

    OpenAIRE

    Neena Sunny; Jinu John

    2014-01-01

    The main environmental problems of fish industries are high water consumption and high organic matter, oil and grease, ammonia, nitrogen and salt contents in the waste water. Aeration helps in the oxidation of these minerals. This paper consequently focuses on how the various constituents of waste water vary with aeration. Diffused fine bubble aeration was done in a circular tank at various flow rates (3 l/minute,6.2 l/minute.6.4l/minute) at a constant time period of 20 hours ...

  15. HYDRAULIC RESEARCH OF AERATORS ON TUNNEL SPILLWAYS

    Institute of Scientific and Technical Information of China (English)

    RUAN Shi-ping; WU Jian-hua; WU Wei-wei; XI Ru-ze

    2007-01-01

    The selection of the configuration and size of an aerator was of importance for a tunnel spillway under the conditions of high speed flows. Experimental investigations were conducted on the effects of entrained air on the tunnel spillway in the Goupitan Project, based on the criterion of gravity similarity and the condition of aerated flow velocity of over 6 m/s, with physical models. The configurations of the aerators were presented of a larger bottom air concentration, to protect the tunnel spillway from cavitation as well as to see no water fills in the grooves.

  16. Winery Wastewater Treatment Applying Aerated Submerged

    Directory of Open Access Journals (Sweden)

    Alessandra Pellizzaro Bento

    2010-06-01

    Full Text Available The winery wastewater usually shows conditions of low pH, high organic loads and concentrations of carbon, nitrogen and phosphorus that are inappropriate for biologic treatment. The purpose of this research was to apply the technology of aerated submerged biofilter (ASB for the winery effluent treatment during the harvest (ASB 1 and non harvest (ASB 2 at lab scale. Therefore, two up flow biofilter built on glass (5 liters volume were installed. The nutrient balance of the winery wastewater was adjusted and the correction of the pH was done by oyster shell used as filter material. The efficiency removal (COD for the harvest reactor was 90% while for the non harvest was 82%. The oyster shells contributed to an increase on average of 180 mg/L of alkalinity to the BAS 1 and 318 mg/L for the BAS 2. As regards the metals, the average values in the treated effluent to meet iron and zinc is permitted by the environmental standards of Santa Catarina. Under the experimental conditions applied in this research, this kind of reactor has presented potential for the treatment of winery wastewater. However, operational improvements would be required in the reactors to adequate them to the specific management into the wineries.

  17. Carbon trading and carbon taxation: how to consider biotic sources and sinks

    International Nuclear Information System (INIS)

    The Kyoto Protocol (KP) to the UNFCCC includes land-use change and forestry in the carbon accounting process, limited to afforestation, reforestation and deforestation since 1990, and explicitly provides for the option of using a variety of flexibility mechanisms to meet the greenhouse gas (GHG) reduction targets stipulated in a more cost-efficient manner. Domestically, different countries might adopt different approaches to achieve their emission reduction objectives, such as carbon trading or carbon taxation, and it is not clear to date what the implications for bioenergy use, forestry, and land-use change can be expected to be. With respect to national GHG emissions trading, the main issues studied in this paper are: Should trading of fossil fuel emissions allowances be coupled with trading of biotic credits and debits? Should credits for carbon sequestration in forests be auctioned or grandfathered? Should there be a distinction between a carbon permit issued for an additional biotic sink and those issued for fossil fuel carbon emissions? Is there a difference for biotic carbon sinks and sources between one-time permits and permits that allow a continued release of GHG over some pre-specified time? Should permits be issued only for the carbon-stock changes that count under the KP? With respect to national carbon taxation schemes, two questions are investigated: Should a tax credit be given for afforestation/reforestation (and a tax debit for deforestation)? Should tax credits also be given for projects that sequester carbon but do not count under the KP (such as forest protection rather than forest management)? For both schemes a crucial point is that by the formulation chosen in the KP two different classes of forest are created (i.e. those counted and those not counted under the KP), so that the implications for land prices might be significant. From a conceptual point of view this paper addresses the above-mentioned questions and contrasts some of the major

  18. The use of organic wastes at different degrees of maturity as carbon sources for denitrification of landfill leachate.

    Science.gov (United States)

    Plüg, B D; Cibati, A; Trois, C

    2015-12-01

    In this study different garden refuses were investigated to ascertain their efficiency to act as carbon sources in a denitrification system. Six different garden refuse materials were studied: commercial and domestic garden refuse raw (CGR RAW, DGR RAW), immaturely composted domestic and commercial garden refuse (DGR 10 and CGR 10 respectively), commercial garden refuse composted by Dome Aeration Technology and by "turned windrow" technology (DAT and TW). Different concentrations of synthetic nitrate solution were used to assess the efficiency of each substrate. The results demonstrate that all substrates were able to sustain the denitrification process. However, due to its higher C/N ratio the CGR RAW was the better performing of the materials, reaching 100% removal after 8 and 12h for the 100 and 500 mg L(-1) respectively and after 11 days for 2000 mg L(-1). Kinetic studies revealed that the zero-order reaction better describes the process indicating a denitrification rate independent from the nitrate concentrations investigated when 100 and 500 mg L(-1) of nitrate were used. The study demonstrated the suitability of organic municipal solid wastes to sustain denitrification, opening a new scenario towards a low cost and in situ solution for treatment of landfill leachate by using wastes, otherwise disposed of in landfill. PMID:26431678

  19. DETERMINATION METHODOLOGY OF BIOMASS AND PAC AT AERATION UNIT IN PACT PROCESS

    Directory of Open Access Journals (Sweden)

    N.Jaffarzadeh

    2000-12-01

    Full Text Available In this research using two pilot scale systems of activated sludge (AS and powdered activated carbon technology (PACT, the soluble organic load removal efficiency was evaluated, for a synthetic wastewater with mono-ethylene glycol as carbon source. Also, the variations of biomass and PAC in each reactor were studied and the relative accuracy of differential ignition method for determining the amount of biomass and powdered activated carbon (combined in aeration unit of the PACT pilot was investigated. Results showed that the method might be used for the determination of PAC and biomass volatility at 400°C and 50°C, respectively, with acceptable accuracy. Comparison the results of this study and some other recent studies, show that there are no significant differences between them at 95% confidence. Furthermore, the results of this study indicated that there was little difference in carbon to biomass ratio which supports the concept that solid residence time (SRT and the amount of wastage sludge can be determined with total suspended solids analysis and there is no necessity for biomass determination

  20. Trace Metal Source Terms in Carbon Sequestration Environments

    Energy Technology Data Exchange (ETDEWEB)

    Karamalidis, Athanasios K; Torres, Sharon G; Hakala, J Alexandra; Shao, Hongbo; Cantrell, Kirk J; Carroll, Susan

    2012-02-05

    Carbon dioxide sequestration in deep saline and depleted oil geologic formations is feasible and promising, however, possible CO₂ or CO₂-saturated brine leakage to overlying aquifers may pose environmental and health impacts. The purpose of this study was to experimentally define trace metal source terms from the reaction of supercritical CO₂, storage reservoir brines, reservoir and cap rocks. Storage reservoir source terms for trace metals are needed to evaluate the impact of brines leaking into overlying drinking water aquifers. The trace metal release was measured from sandstones, shales, carbonates, evaporites, basalts and cements from the Frio, In Salah, Illinois Basin – Decatur, Lower Tuscaloosa, Weyburn-Midale, Bass Islands and Grand Ronde carbon sequestration geologic formations. Trace metal dissolution is tracked by measuring solution concentrations over time under conditions (e.g. pressures, temperatures, and initial brine compositions) specific to the sequestration projects. Existing metrics for Maximum Contaminant Levels (MCLs) for drinking water as defined by the U.S. Environmental Protection Agency (U.S. EPA) were used to categorize the relative significance of metal concentration changes in storage environments due to the presence of CO₂. Results indicate that Cr and Pb released from sandstone reservoir and shale cap rock exceed the MCLs by an order of magnitude while Cd and Cu were at or below drinking water thresholds. In carbonate reservoirs As exceeds the MCLs by an order of magnitude, while Cd, Cu, and Pb were at or below drinking water standards. Results from this study can be used as a reasonable estimate of the reservoir and caprock source term to further evaluate the impact of leakage on groundwater quality.

  1. The Influence of Aerator Mounting and Wastewater Treatment Plant Design on the Performance of Aeration Systems

    OpenAIRE

    Ala Sokolova; Mindaugas Rimeika

    2011-01-01

    The paper analyzes the impact of the way of mounting a tube diffuser, the design of an aeration tank and the presence of a fixed carrier on the operational parameters of aeration systems used in small wastewater treatment plants. It was found out that the vertically mounted tube diffuser decreased standard oxygen transfer rate (SOTR) of the aeration system by approximately 20% and standard oxygen transfer efficiency (SOTE) by 25% comparing to the horizontally mounted tube diffuser. It was als...

  2. Achieving high performance in intermediate temperature direct carbon fuel cells with renewable carbon as a fuel source

    International Nuclear Information System (INIS)

    Highlights: • Bamboo fiber and waste paper were pyrolyzed to generate bamboo carbon and waste paper carbon as anode fuels of IT-DCFC. • Superior cell performance was achieved with the waste paper carbon. • The results suggested the high performance was due to the highest thermal reactivity and the catalytic inherent impurities. • Calcite and kaolinite as inherent impurities favored the thermal decomposition and the electrooxidation of carbon. - Abstract: Three kinds of carbon sources obtained from carbon black, bamboo fiber and waste paper were investigated as anode fuels in an intermediate temperature direct carbon fuel cell. The carbon sources were characterized with X-ray photoelectron spectroscopy, thermal gravimetric analysis, etc. The results indicated that the waste paper carbon was more abundant in calcite and kaolinite, and showed higher thermal reactivity in the intermediate temperature range compared with the other two carbon sources. The cell performance was tested at 650 °C in a hybrid single cell, using Sm0.20Ce0.80O2−x as the electrolyte. As a result, the cell fed with waste paper carbon showed the highest performance among the three carbon sources, with a peak power density of 225 mW cm−2. The results indicated that its inherent impurities, such as calcite and kaolinite, might favor the thermal gasification of renewable carbon sources, which resulted in the enhanced performance of the intermediate temperature direct carbon fuel cell

  3. Utilization of carbon sources in a northern Brazilian mangrove ecosystem

    Science.gov (United States)

    Giarrizzo, Tommaso; Schwamborn, Ralf; Saint-Paul, Ulrich

    2011-12-01

    Carbon and nitrogen stable isotope ratios ( 13C and 15N) and trophic level (TL) estimates based on stomach content analysis and published data were used to assess the contribution of autotrophic sources to 55 consumers in an intertidal mangrove creek of the Curuçá estuary, northern Brazil. Primary producers showed δ 13C signatures ranging between -29.2 and -19.5‰ and δ 15N from 3.0 to 6.3‰. The wide range of the isotopic composition of carbon of consumers (-28.6 to -17.1‰) indicated that different autotrophic sources are important in the intertidal mangrove food webs. Food web segregation structures the ecosystem into three relatively distinct food webs: (i) mangrove food web, where vascular plants contribute directly or indirectly via POM to the most 13C-depleted consumers (e.g. Ucides cordatus and zooplanktivorous food chains); (ii) algal food web, where benthic algae are eaten directly by consumers (e.g. Uca maracoani, mullets, polychaetes, several fishes); (iii) mixed food web where the consumers use the carbon from different primary sources (mainly benthivorous fishes). An IsoError mixing model was used to determine the contributions of primary sources to consumers, based on δ 13C values. Model outputs were very sensitive to the magnitude of trophic isotope fractionation and to the variability in 13C data. Nevertheless, the simplification of the system by a priori aggregation of primary producers allowed interpretable results for several taxa, revealing the segregation into different food webs.

  4. DESIGN MANUAL: FINE PORE AERATION SYSTEMS

    Science.gov (United States)

    This manual presents the best current practices for selecting, designing, operating, maintaining, and controlling fine pore aeration systems used in the treatment of municipal wastewater. It was prepared by the American Society of Civil Engineers Committee on Oxygen Transfer unde...

  5. EMERGENCE ANGLE OF FLOW OVER AN AERATOR

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Aerator is an important device for release works of hydraulic structures with high-speed flow in order to protect them from cavitation damage. This kind of protecting effect is related closely to cavity length below the aerator, while the cavity length is dominated by the emergence angle over the aerator. Therefore it is crucial to determine this angle accurately. In the present paper the affecting intensities of flow depth and the fluctuating velocity on this angle were analyzed through two introduced parameters. Furthermore, the improved expressions of emergence angle estimation, for both ramp-type and step-type aerators, were presented by means of 68 sets of experimental data from 6 projects based on error theory. The results showed that the present method has higher accuracy than the previously reported methods.

  6. T.A. BROWN MECHANICAL AERATOR

    Science.gov (United States)

    Students in the Environmental Engineering and Waster Resources capstone design class in the Department of Civil and Environmental Engineering will undertake a project in conjunction with Serasih Indonesia to develop a prototype mechanical aerator to be used in aquaculture live...

  7. Ligninolytic Activity of Ganoderma strains on Different Carbon Sources

    Directory of Open Access Journals (Sweden)

    TYPUK ARTININGSIH

    2006-10-01

    Full Text Available Lignin is a phenylpropanoid polymers with only few carbon bonds might be hydrolized. Due to its complexity, lignin is particularly difficult to decompose. Ganoderma is one of white rot fungi capable of lignin degradation. The ligninolytic of several species Ganoderma growing under different carbon sources was studied under controlled conditions which P. chrysosporium was used as standard comparison.Three types of ligninolytic, namely LiP, MnP, and laccase were assessed quantitatively and qualitatively. Ratio between clear zone and diameter of fungal colony was used for measuring specific activity qualitatively.Four sspecies of Ganoderma showed positive ligninolytic qualitatively that G. lucidum KT2-32 gave the highest ligninolytic. Activity of LiP and MnP in different carbon sources was consistently resulted by G. lucidum KT2-32, while the highest activity of laccase was shown by G. ochrolaccatum SA2-14. Medium of Indulin AT affected production of protein extracellular and induced ligninolytic. Glucose, BMC, and pine sawdust did not affect the activity of ligninolytic. The specific activity of Ganoderma species was found to be higher than the one of P. chrysosporium.

  8. Carbon sources and fates in the Gulf of Papua

    Science.gov (United States)

    Goni, M. A.; Monacci, N. M.; Gisewhite, R. A.; Ogston, A.; Crockett, J.; Nittrouer, C.

    2006-12-01

    Seabed sediments were collected along the particle-dispersal system associated with the Fly River-Gulf of Papua continental margin as part of the source to sink program in Papua New Guinea. Box and kasten cores were collected from the subaqueous delta located adjacent to the mouth of the Fly River as well as from the topset, foreset and bottomset regions of the active clinoform in the northern region of the Gulf of Papua. Analyses of elemental (organic carbon, inorganic carbon, nitrogen), stable isotopic (d13C and d15N), radiocarbon (14C), and biomarker (CuO oxidation products) signatures reveal significant differences in the content and composition of sedimentary organic matter (OM) along the dispersal system. The major sources of OM to the system appear to be remains of vascular plants, soil OM from the drainage basin, and materials derived from autochthonous productivity. The geographical contrasts in the concentrations and accumulation fluxes of these distinct types of allochthonous and autochthonous OM are presented in the context of patterns of sediment transport and deposition within the region. An overall OM budget for the whole dispersal system will be presented and its implication for carbon sequestration in fluvial-dominated continental margins discussed.

  9. Intermittent Aeration in Biological Treatment of Wastewater

    OpenAIRE

    Doan, H.; Lohi, A.

    2009-01-01

    Problem statement: E-coating process is widely used to provide a protective coating layer on metal parts in the automotive and metal finishing industry. The wastewater from the coating process contains organic compounds that are used in the cleaning, pretreatment and coating steps. Organic pollutants can be removed biologically. In the aerobic biological treatment, water aeration accounts for a significant portion of the total operating cost of the treatment process. Intermittent aeration is ...

  10. Carbon Isotopic Constraints on Arctic Methane Sources, 2008-2010

    Science.gov (United States)

    Fisher, R. E.; Lowry, D.; Lanoiselle, M.; Sriskantharajah, S.; Nisbet, E. G.

    2010-12-01

    Arctic methane source strengths are particularly vulnerable to large changes with year-to year meteorological variations and with climatic change. A global increase in methane seen in 2007 (Dlugokencky et al., 2009) may have been in part be due to elevated wetland emissions caused by a warm, wet summer over large parts of Siberia. In 2010 wildfires over large areas of Russia will have added methane to the Arctic atmosphere. Carbon isotopic composition of methane in air from the Arctic arriving at a measurement station can be used to identify sources of the gas. Measurement of methane δ13C in air close to sources, including wetlands, permafrost, pine forest and submarine methane clathrate has extended the available data of source signatures of methane from northern sources. Keeling plot analysis of diurnal records from field campaigns in Arctic wetlands show that bulk wetland methane emissions are typically close to δ13CCH4 -69±1 ‰. Air samples from Zeppelin (Spitsbergen, Norway), Pallas (Finland) and Barra (Outer Hebrides, Scotland) have been regularly analysed for methane δ13C. Summer campaigns at Zeppelin point to a 13C depleted bulk Arctic source of dominantly biogenic origin, at -67‰. In spring, while the wetlands are still frozen, the source signature is more enriched, -53‰, with trajectory analysis implying a large contribution from onshore gas fields. Arctic methane emissions respond rapidly to warming with strong positive feedbacks. With rapid warming there is the potential to release large stores of carbon from permafrost and methane hydrates. Isotopic data are powerful discriminants of sources. High frequency, ideally continuous, monitoring of methane δ13C from a number of Arctic sites, onshore and offshore, coupled with back-trajectory analysis and regional modelling, will be important if future changes in Arctic source strengths are to be quantified. Reference: Dlugokencky, E. J., et al. (2009), Observational constraints on recent increases

  11. MEDIA OPTIMIZATION FOR BIOPROTEINS PRODUCTION FROM CHEAPER CARBON SOURCE

    Directory of Open Access Journals (Sweden)

    P. JAMAL

    2008-08-01

    Full Text Available There are high demands for animal and human food supply especially protein, which is an important dietary component. Agricultural wastes, cheap carbon sources- which are rich and have high energy, can be used for producing the value added bioprotein. A lab scale study was carried out to optimize the media composition for bioprotein production from a cheaper carbon source - wheat flour using potential strain, which was selected earlier by screening different microorganisms. The performance of the selected strain was enhanced by media optimization with varied substrate concentration, nitrogen sources and nutrient supplementation according to the central composite design from STATISTICA software. Statistical optimization was carried out to evaluate the polynomial regression model through effect of linear, quadratic and interaction of the factors. The maximum biomass produced was 21.89 g/L with optimum fermentation conditions of wheat flour (4 g/L, nitrogen concentration (0.5 g/L, nutrient concentration (0.1 g/L, and four days of fermentation.

  12. Kupier prize lecture: Sources of solar-system carbon

    Science.gov (United States)

    Anders, Edward; Zinner, Ernst

    1994-01-01

    We have tried to deconvolve Solar-System carbon into its sources, on the basis of C-12/C-13 ratios (equivalent to R). Interstellar SiC in meteorites, representing greater than 4.6-Ga-old stardust from carbon stars, is isotopically heavier (bar R = 38 +/- 2) than Solar-System carbon (89), implying that the latter contains an additional, light component. A likely source are massive stars, mainly Type II supernovae and Wolf-Rayet stars, which, being O-rich, eject their C largely as CO rather than carbonaceous dust. The fraction of such light C in the Solar System depends on R(sub light) in the source. For R(sub light) = 180-1025 (as in 'Group 4' meteoritic graphite spherules, which apparently came from massive stars greater than 4.6 Ga ago), the fraction of light C is 0.79-0.61. Similar results are obtained for present-day data on red giants and interstellar gas. Although both have become enriched in C-13 due to galactic evolution (to bar-R = 20 and 57), the fraction of the light component in interstellar gas again is near 0.7. (Here bar R represents the mean of a mixture calculated via atom fractions; it is not identical to the arithmetic mean R). Interstellar graphite, unlike SiC, shows a large peak at R approximately equal 90, near the solar value. Although some of the grains may be of local origin, others show anomalies in other elements and hence are exotic. Microdiamonds, with R = 93, also are exotic on the basis of their Xe and N. Apparently R approximately 90 was a fairly common composition 4.6 Ga ago, of stars as well as the ISM.

  13. A Low Carbon EU Energy System and Unconventional Sources

    International Nuclear Information System (INIS)

    The paper investigates the potential role of unconventional fossil fuels in a global low carbon energy system. Making use of a systemic approach, the paper presents an original application of a global partial equilibrium energy system model (TIAM-JET). In order to give a worldwide perspective with higher detail on European energy systems, the model links a set of extra-European macro-regions to the 30 European countries. First, a review of the most recent estimates of the available stocks of unconventional hydrocarbon resources is used to build the set of assumption for the scenario analysis. Secondly, a set of scenarios assuming different availability and cost of unconventional fuels are added to both a Current Trend scenario and a Carbon Constrained (CC) scenario, to explore the perspectives of unconventional gas and oil in a scenario halving CO2 emissions by 2050, which is consistent with a 2 degree temperature increase. The results show if/how unconventional sources can contribute to the robustness of the European energy system with respect to the stress of a strong carbon constraint. We define this robustness as the capacity of the energy system to adapt its evolution to long-term constraints and keep delivering energy services to end users. In our approach robustness represents the long-term dimension of energy security. Assessing this ''system property'' requires analysing the wide range of factors that can exercise a stabilizing influence on the energy services delivery system, together with their relations, actual interactions and synergies. The energy system approach used for the analysis seeks to take into account as much of this complexity as possible. We assess the robustness of the EU system to the carbon constraint by looking at how the CC scenario affects energy system costs and energy prices under scenarios with different deployment of unconventional sources. This provides insights on the synergies and/or trade-offs between energy security and

  14. Quantification of carbon sources for isoprene emission in poplar leaves

    Science.gov (United States)

    Kreutzwieseer, J.; Graus, M.; Schnitzler, J. P.; Heizmann, U.; Rennenberg, H.; Hansel, A.

    2003-12-01

    Isoprene is the most abundant volatile organic compound emitted by plants and in particular by trees. Current interest in understanding its biosynthesis in chloroplasts is forced by the important role isoprene plays in atmospheric chemistry. Leaf isoprene formation is closely linked to photosynthesis by a dynamic use of recently fixed photosynthetic precursors in the chloroplast. Under steady state conditions in [13C]CO2 atmosphere approximately 75 % of isoprene became labeled within minutes. The source of unlabeled C is suggested to be of extra-chloroplastidic and/or from starch degradation. In order to test whether these alternative carbon sources - leaf internal C-pools and xylem-transported carbohydrates, contribute to leaf isoprene formation in poplar (Populus tremula x P. alba) on-line proton-transfer-reaction-mass spectrometry (PTR-MS) was used to follow 13C-labeling kinetics.

  15. Air-source heat pump carbon footprints: HFC impacts and comparison to other heat sources

    International Nuclear Information System (INIS)

    European governments see that heat pumps could reduce carbon emissions in space- and hot-water heating. EU's Renewable Energy Directive designates heat pumps as renewable - eligible for various subsidies - if their carbon footprints are below an implied, average threshold. This threshold omits carbon generated by manufacture and emission of a heat-pump's fluorocarbon refrigerant. It also omits the footprint of the heat pump's hardware. To see if these omissions are significant, this study calculated carbon footprints of representative, residential heat pumps in the UK. Three findings emerged. First, in relation to power generation, which accounts for most of a heat-pump's greenhouse-gas emissions, fluorocarbons add another 20% to the footprint. Second, at UK efficiencies a heat-pump footprint (in kg CO2e emitted per kWh delivered) is comparable or higher than footprints of gaseous fuels used in heating. It is lower than the footprint of heating oil and far lower than the footprints of solid fuels. Third, production and disposal of a heat pump's hardware is relatively insignificant, accounting for only 2-3% of the overall heat-pump footprint. Sensitivities to the results were assessed: key factors are footprint of electricity generation, F-gas composition and leak rates and type of wall construction. - Research highlights: → Refrigerant emissions add 20% to a UK air-source heat pump's carbon footprint. → This contribution is so far ignored by regulations. → UK heat pump footprints are comparable to those of gaseous fuels.

  16. Barrow Black Carbon Source and Impact Study Final Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Tate [Baylor Univ., Waco, TX (United States)

    2014-07-01

    The goal of the Barrow Black Carbon Source and Impact (BBCSI) Study was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement site in Barrow, AK. The carbonaceous component was characterized via measurement of the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the particulate matter, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine (PM2.5) and 49 coarse (PM10) particulate matter fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the BBCSI used standard Tisch hi-vol motors which have a known lifetime of ~1 month under constant use; this necessitated monthly maintenance and it is suggested that the motors be upgraded to industrial blowers for future deployment in the Arctic. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric particulate matter samples from Barrow, AK from July 2012 to June 2013. Preliminary analysis of the organic and black carbon concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer.

  17. Effect of C/N ratio, aeration rate and moisture content on ammonia and greenhouse gas emission during the composting

    Institute of Scientific and Technical Information of China (English)

    Tao Jiang; Frank Schuchardt; Guoxue Li; Rui Guo; Yuanqiu Zhao

    2011-01-01

    Gaseous emission (N2O,CH4 and NH3) from composting can be an important source of anthropogenic greenhouse gas and air pollution.A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio,aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system.The resnits showed that about 23.9%to 45.6% of total organic carbon (TOC) was lost in the form of CO2 and 0.8% to 7.5% of TOC emitted as CH4.Most of the nitrogen was lost in the form of NH3,which account for 9.6% to 32.4% of initial nitrogen.N2O was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it.Statistic analysis showed that the aeration rate is the most important factor which could affect the NH3 (p =0.0189),CH4 (p =0.0113) and N2O (p =0.0493) emissions significantly.Higher aeration rates reduce the CH4 emission but increase the NH3 and N2O losses.C/N ratio could affect the NH3 (p =0.0442) and CH4 (p =0.0246) emissions significantly,but not the N2O.Lower C/N ratio caused higher NH3 and CH4 emissions.The initial moisture content can not influence the gaseous emission significantly.Most treatments were matured after 37 days,except a trial with high moisture content and a low C/N ratio.

  18. Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste

    International Nuclear Information System (INIS)

    Highlights: • Effect of micro-aeration on acidogenesis and hydrolysis of food waste was investigated. • Micro-aeration at 258 L-air/kg TS/d increased the VFAs production 3-fold. • High aeration leads to loss of substrate through microbial biomass and respiration. • Optimum aeration increased methane recovery while high aeration intensity reduced methane yield. - Abstract: Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35 °C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21–27% and 38–64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH4/g VSadded in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO2 respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste

  19. Barrow Black Carbon Source and Impact Study Final Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Tate

    2014-07-01

    The goal of the Barrow Black Carbon Source and Impact campaign was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement (ARM) Climate Research Facility site in Barrow, Alaska. The carbonaceous component was characterized by measuring the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the PM, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine PM fractions (PM2.5) and 49 coarse (PM10) PM fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the Barrow Black Carbon Source and Impact (BBCSI) study used standard Tisch “hi-vol” motors that have a known lifetime of approximately 1 month under constant use; this necessitated monthly maintenance, and it is suggested that, for future deployment in the Arctic, the motors be upgraded to industrial blowers. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric PM samples from Barrow, Alaska, from July 2012 to June 2013. Preliminary analysis of the OC and BC concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer. However, the annual OC concentrations had a very different seasonal pattern with the highest concentrations during the summer, lowest concentrations during the fall, and increased concentrations during the winter and spring (Figure 1).

  20. Carbon dioxide as a carbon source in organic transformation: carbon-carbon bond forming reactions by transition-metal catalysts.

    OpenAIRE

    Tsuji, Yasushi; Fujihara, Tetsuaki

    2012-01-01

    Recent carbon-carbon bond forming reactions of carbon dioxide with alkenes, alkynes, dienes, aryl zinc compounds, aryl boronic esters, aryl halides, and arenes having acidic C-H bonds are reviewed in which transition-metal catalysts play an important role.

  1. Effect and mechanism of carbon sources on phosphorus uptake by microorganisms in sequencing batch reactors with the single-stage oxic process

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    To investigate the chief reason for phosphorus uptake by microorganisms affected by substrates in sequencing batch reactors with the single-stage oxic process,two typical substrates,glucose (R1) and acetate (R2) were used as the sole carbon source,and the performances of phosphorus removal and the changes of intracellular storage were compared. The experimental results showed that the phenomenon of excess phosphorus uptake was observed in two reactors,but bacteria’s capability to take in phosphorus and its intracellular storage were obviously different under the same operational condition. After steady-state operation,total phosphorus (TP) removed per MLVSS in R1 and R2 was 6.7―7.4 and 2.7―3.2 mg/g,respectively. The energy storage of poly-β-hydroxyalkanoates (PHA) was nearly constant in R1 during the whole period,and another aerobic storage of glycogen was accumulated (the max accumulation of glycogen was 3.21 mmol-C/g) when external substrate was consumed,and then was decreased to the initial level. However in R2,PHA and glycogen were both accumulated (2.1 and 0.55 mmol-C/g,respectively) when external substrate was consumed,but they showed different changes after the period of external consumption. Compared to rapid decrease of PHA to the initial level,glycogen continued accumulating to the peak (0.88 mmol-C/g) in 2 h of aeration before decreasing. During the aeration,the accumulations/transformations of internal carbon sources in R1 were higher than those in R2. In addition,obvious TP releases were both observed in R1 and R2 other than PHA and glycogen during the long-term idle period; moreover,the release content of phosphorus in R1 was also higher than that in R2. The researches indicated that different aerobic metabolism of substrate occurred in R1 and R2 due to the different carbon sources in influent,resulting in different types and contents of aerobic storage accumulated/translated in bacteria of R1 and R2. As a result,ATP content provided for

  2. Effects of aeration on gamma irradiation of sewage sludge

    International Nuclear Information System (INIS)

    In this paper the effect of aeration on gamma irradiation of sewage sludge was investigated to examine the potential solubilization of solids in sewage sludge to ultimately reduce the solids volume for disposal. Results showed that aeration increased the effectiveness of gamma radiation. The efficiency of sludge solubilization with aeration was increased by around 25% compared to that without aeration at an irradiation dose of 2.5-9 kGy. The soluble protein, polysaccharide and humic (like) substance concentrations were higher under aerated conditions. With aeration the overall reaction appears to be oxidative as evidenced by the higher nitrate and nitrite ion concentrations in solution.

  3. Effects of aeration on gamma irradiation of sewage sludge

    Science.gov (United States)

    Chu, Libing; Wang, Jianlong; Wang, Bo

    2010-08-01

    In this paper the effect of aeration on gamma irradiation of sewage sludge was investigated to examine the potential solubilization of solids in sewage sludge to ultimately reduce the solids volume for disposal. Results showed that aeration increased the effectiveness of gamma radiation. The efficiency of sludge solubilization with aeration was increased by around 25% compared to that without aeration at an irradiation dose of 2.5-9 kGy. The soluble protein, polysaccharide and humic (like) substance concentrations were higher under aerated conditions. With aeration the overall reaction appears to be oxidative as evidenced by the higher nitrate and nitrite ion concentrations in solution.

  4. Growth of oleaginous Rhodotorula glutinis in an internal-loop airlift bioreactor by using lignocellulosic biomass hydrolysate as the carbon source.

    Science.gov (United States)

    Yen, Hong-Wei; Chang, Jung-Tzu

    2015-05-01

    The conversion of abundant lignocellulosic biomass (LCB) to valuable compounds has become a very attractive idea recently. This study successfully used LCB (rice straw) hydrolysate as a carbon source for the cultivation of oleaginous yeast-Rhodotorula glutinis in an airlift bioreactor. The lipid content of 34.3 ± 0.6% was obtained in an airlift batch with 60 g reducing sugars/L of LCB hydrolysate at a 2 vvm aeration rate. While using LCB hydrolysate as the carbon source, oleic acid (C18:1) and linoleic acid (C18:2) were the predominant fatty acids of the microbial lipids. Using LCB hydrolysate in the airlift bioreactor at 2 vvm achieved the highest cell mass growth as compared to the agitation tank. Despite the low lipid content of the batch using LCB hydrolysate, this low cost feedstock has the potential of being adopted for the production of β-carotene instead of lipid accumulation in the airlift bioreactor for the cultivation of R. glutinis. PMID:25454603

  5. Evaluation and optimization of growth and citric acid production by Yarrowia lipolytica NRRL Y-1095 using glycerol as carbon source as an alternative to use biodiesel byproduct

    Directory of Open Access Journals (Sweden)

    Avila-Neto P M

    2014-02-01

    Full Text Available The aim of the present study was to optimize growth and citric acid production by Yarrowia lipolytica NRRL Y-1095 using glycerol as the sole carbon source, like an alternative to use biodiesel glycerol, a promising and cheap carbon source. Fermentations were performed in Erlenmeyer flasks to optimize growth and citrate production from glycerol. The fermented broth was analyzed by HPLC equipped with a UV and RI detector to evaluate isocitrate, citrate and glycerol consumption. The growth medium was optimized in flasks and in batch fermentation. The present study have optimized media conditions for the growth phase of Yarrowia lipolityca NRRL Y-1095 using experimental design and surface response methodology, obtaining 6.18 g.l-1 of dry cell weight (DCW and up to 22 g.l-1 DCW in bioreactor after 96 h. Six fermentations were performed in a feed batch reactor with varying aeration and agitation. Dissolved oxygen was an important factor and a 0.5 yield of citric acid was obtained from feed batch fermentation, where up to 59 g.l-1 of citric acid was obtained. Glycerol is a cheap alternative to citric acid production since biodiesel glycerol production is growing rapidly and becoming an environmental problem.

  6. Effect of Aeration on Seafood Processing Wastewater

    Directory of Open Access Journals (Sweden)

    Neena Sunny

    2014-04-01

    Full Text Available The main environmental problems of fish industries are high water consumption and high organic matter, oil and grease, ammonia, nitrogen and salt contents in the waste water. Aeration helps in the oxidation of these minerals. This paper consequently focuses on how the various constituents of waste water vary with aeration. Diffused fine bubble aeration was done in a circular tank at various flow rates (3 l/minute,6.2 l/minute.6.4l/minute at a constant time period of 20 hours using air stones and the percentage reduction in ammonia, total Kjeldahl nitrogen , BOD,COD and salts were found out . It was found that as flow rate of aeration increase the percentage removal of above constituents also increased. Optimum removal was possible at a flow rate of 6.4l/min. BOD, COD, Ammoniacal nitrogen, Kjeldahl nitrogen, were found to be removed by 91.2%, 82.79%,57.76%, 90.6% respectively . Aeration had no effect on salts and lipids .

  7. A Novel Aeration Method for the Preparation of Algae (Dunaliella Salina Biomass for Biofuel Production.

    Directory of Open Access Journals (Sweden)

    U.O. Enwereuzoh

    2014-09-01

    Full Text Available Preparation of algae (Dunaliela Salina biomass in ammonia (NH4 + and nitrate (NO3 - growth media for biofuel production was investigated, with special attention on the elimination of inhibitory oxygen that adversely affects algae growth. A novel aeration method based on high and efficient transfer of carbon dioxide (CO2 required to stabilize the CO2 of the algae growth medium in a short time was adopted for the elimination of the inhibitory oxygen. The novel aeration method was found to increase the algae growth rate in the growth media investigated as suggested by increases in pH and decreases in dissolved oxygen concentration. However, algae grown in ammonia medium showed 17% higher growth rate than algae grown in nitrate medium. The high mass transfer of CO2 and high energy efficiency make the novel aeration method of algae growth in ammonia medium better suited for high yield of algae biomass for biofuel production.

  8. Sawdust discharge rate from aerated hoppers

    Institute of Scientific and Technical Information of China (English)

    Pan Chen; Zhulin Yuan; Chien-Song Chyang; Fu-Xiong Zhuan

    2011-01-01

    This paper presents a numerical and experimental study of the discharge rate of sawdust from an aerated hopper as an important parameter in many industrial processes involving the handling of other granular materials. Numerical experiments are conducted by means of an Eulerian-Eulerian approach coupled with the kinetic theory of granular flow (KTGF). Emphasis is given to the effects of particle size, hopper outlet width, hopper half angle, aeration height and air flow rate. The results show that the discharge rate is significantly affected by hopper outlet width, particle size and air flow rate, but is not sensitive to the hopper half angle and aeration height: increasing hopper outlet width or air flow rate increases discharge rate, while increasing particle size decreases discharge rate. Close agreement between numerical predictions and experimental results is obtained.

  9. FLOW REGIMES BELOW AERATORS FOR DISCHARGE TUNNELS

    Institute of Scientific and Technical Information of China (English)

    MA Fei; WU Jian-hua

    2012-01-01

    The flow regimes below an aerator influence directly the air entrainment and the cavitation damage control.Based on the theoretical considerations,the experiments of the aerator for a discharge tunnel were conducted,and the relationships between the flow regime and hydraulic and geometric parameters were investigated.The results showed that,there are two kinds of threshold values for the flow regime conversions.One is Fr1-2 standing for the conversion from the fully filled cavity to the partially filled cavity,and the other is Fr2-3 which shows the change from the partially filled cavity to the net air cavity.Two empirical expressions were obtained for the conversions of the flow regimes,which can be used in the designs of the aerators.

  10. A Novel Airborne Carbon Isotope Analyzer for Methane and Carbon Dioxide Source Fingerprinting

    Science.gov (United States)

    Berman, E. S.; Huang, Y. W.; Owano, T. G.; Leifer, I.

    2014-12-01

    Recent field studies on major sources of the important greenhouse gas methane (CH4) indicate significant underestimation of methane release from fossil fuel industrial (FFI) and animal husbandry sources, among others. In addition, uncertainties still exist with respect to carbon dioxide (CO2) measurements, especially source fingerprinting. CO2 isotopic analysis provides a valuable in situ measurement approach to fingerprint CH4 and CO2as associated with combustion sources, leakage from geologic reservoirs, or biogenic sources. As a result, these measurements can characterize strong combustion source plumes, such as power plant emissions, and discriminate these emissions from other sources. As part of the COMEX (CO2 and MEthane eXperiment) campaign, a novel CO2 isotopic analyzer was installed and collected data aboard the CIRPAS Twin Otter aircraft. Developing methods to derive CH4 and CO2 budgets from remote sensing data is the goal of the summer 2014 COMEX campaign, which combines hyperspectral imaging (HSI) and non-imaging spectroscopy (NIS) with in situ airborne and surface data. COMEX leverages the synergy between high spatial resolution HSI and moderate spatial resolution NIS. The carbon dioxide isotope analyzer developed by Los Gatos Research (LGR) uses LGR's patented Off-Axis ICOS (Integrated Cavity Output Spectroscopy) technology and incorporates proprietary internal thermal control for high sensitivity and optimal instrument stability. This analyzer measures CO2 concentration as well as δ13C, δ18O, and δ17O from CO2 at natural abundance (100-3000 ppm). The laboratory accuracy is ±1.2 ppm (1σ) in CO2 from 370-1000 ppm, with a long-term (1000 s) precision of ±0.012 ppm. The long-term precision for both δ13C and δ18O is 0.04 ‰, and for δ17O is 0.06 ‰. The analyzer was field-tested as part of the COWGAS campaign, a pre-cursor campaign to COMEX in March 2014, where it successfully discriminated plumes related to combustion processes associated with

  11. The Influence of Aerator Mounting and Wastewater Treatment Plant Design on the Performance of Aeration Systems

    Directory of Open Access Journals (Sweden)

    Ala Sokolova

    2011-02-01

    Full Text Available The paper analyzes the impact of the way of mounting a tube diffuser, the design of an aeration tank and the presence of a fixed carrier on the operational parameters of aeration systems used in small wastewater treatment plants. It was found out that the vertically mounted tube diffuser decreased standard oxygen transfer rate (SOTR of the aeration system by approximately 20% and standard oxygen transfer efficiency (SOTE by 25% comparing to the horizontally mounted tube diffuser. It was also defined that the design of the aeration tank might have an impact on the operation parameters of the aeration system: when the centre shell used to protect a diffuser was dismantled from a test tank, SOTR and SOTE increased by approximately 20%. It was also established that the presence of the fixed carrier in the aeration tank did not have an impact on the performance of aeration systems. Finally, research was carried out to compare the operational parameters of two diffusers of different types offered on the market and used in small wastewater treatment plants. It was found out that the performance different type diffusers  might vary considerably.Article in Lithuanian

  12. Organic carbon in Antarctic snow: spatial trends and possible sources

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, R.; Mahalinganathan, K.; Thamban, M.; Nair, S.

    Organic carbon records in Antarctic snow are sparse despite the fact that it is of great significance to global carbon dynamics, snow photochemistry, and air–snow exchange processes. Here, surface snow total organic carbon (TOC) along with sea...

  13. Addressing sources of uncertainty in a global terrestrial carbon model

    Science.gov (United States)

    Exbrayat, J.; Pitman, A. J.; Zhang, Q.; Abramowitz, G.; Wang, Y.

    2013-12-01

    Several sources of uncertainty exist in the parameterization of the land carbon cycle in current Earth System Models (ESMs). For example, recently implemented interactions between the carbon (C), nitrogen (N) and phosphorus (P) cycles lead to diverse changes in land-atmosphere C fluxes simulated by different models. Further, although soil organic matter decomposition is commonly parameterized as a first-order decay process, the formulation of the microbial response to changes in soil moisture and soil temperature varies tremendously between models. Here, we examine the sensitivity of historical land-atmosphere C fluxes simulated by an ESM to these two major sources of uncertainty. We implement three soil moisture (SMRF) and three soil temperature (STRF) respiration functions in the CABLE-CASA-CNP land biogeochemical component of the coarse resolution CSIRO Mk3L climate model. Simulations are undertaken using three degrees of biogeochemical nutrient limitation: C-only, C and N, and C and N and P. We first bring all 27 possible combinations of a SMRF with a STRF and a biogeochemical mode to a steady-state in their biogeochemical pools. Then, transient historical (1850-2005) simulations are driven by prescribed atmospheric CO2 concentrations used in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Similarly to some previously published results, representing N and P limitation on primary production reduces the global land carbon sink while some regions become net C sources over the historical period (1850-2005). However, the uncertainty due to the SMRFs and STRFs does not decrease relative to the inter-annual variability in net uptake when N and P limitations are added. Differences in the SMRFs and STRFs and their effect on the soil C balance can also change the sign of some regional sinks. We show that this response is mostly driven by the pool size achieved at the end of the spin-up procedure. Further, there exists a six-fold range in the level

  14. Size distributions, sources and source areas of water-soluble organic carbon in urban background air

    Directory of Open Access Journals (Sweden)

    H. Timonen

    2008-09-01

    Full Text Available This paper represents the results of one year long measurement period of the size distributions of water-soluble organic carbon (WSOC, inorganic ions and gravimetric mass of particulate matter. Measurements were done at an urban background station (SMEAR III by using a micro-orifice uniform deposit impactor (MOUDI. The site is located in northern European boreal region in Helsinki, Finland. The WSOC size distribution measurements were completed with the chemical analysis of inorganic ions, organic carbon (OC and monosaccharide anhydrides from the filter samples (particle aerodynamic diameter smaller than 1 μm, PM1. Gravimetric mass concentration varied during the MOUDI samplings between 3.4 and 55.0 μg m−3 and the WSOC concentrations were between 0.3 and 7.4 μg m−3. On average, water-soluble particulate organic matter (WSPOM, WSOC multiplied by 1.6 to convert the analyzed carbon mass to organic matter mass comprised 25±7.7% and 7.5±3.4% of aerosol PM1 mass and the PM1–10 mass, respectively. Inorganic ions contributed 33±12% and 28±19% of the analyzed PM1 and PM1–10 aerosol mass.

    Five different aerosol categories corresponding to different sources or source areas were identified (long-range transport aerosols, biomass burning aerosols from wild land fires and from small-scale wood combustion, aerosols originating from marine areas and from the clean arctic areas. Categories were identified mainly using levoglucosan concentration level for wood combustion and air mass backward trajectories for other groups. Clear differences in WSOC concentrations and size distributions originating from different sources or source areas were observed, although there are also many other factors which might affect the results. E.g. the local conditions and sources of volatile organic compounds (VOCs and aerosols as well as various transformation processes are likely

  15. Carbon Nanotube/Magnesium Composite as a Hydrogen Source.

    Science.gov (United States)

    Yu, Min Kyu; Se, Kwon Oh; Kim, Min Joong; Hwang, Jae Won; Yoon, Byoung Young; Kwon, Hyuk Sang

    2015-11-01

    Hydrogen produced using the steam reforming process contains sulfur and carbon monoxide that are harmful to the Pt catalyst in proton-exchange-membrane fuel cells (PEMFCs). However, CO-free hydrogen can be generated from the hydrolysis of either Al in strongly alkaline water or Mg in neutral water with chlorides such as sea water. The hydrogen generation rate from the hydrolysis of Mg is extremely slow and linearly proportional to the corrosion rate of Mg in chloride water. In this work, we fabricated a carbon nanotube (CNT)--reinforced Mg--matrix composite by Spark Plasma Sintering as a fast hydrogen generation source for a PEMFC. The CNTs distributed in the Mg matrix act as numerous local cathodes, and hence cause severe galvanic corrosion between the Mg-matrix anode and CNT-cathode in NaCl solution. It was found that the hydrogen generation rate from the hydrolysis of the 5 vol.% CNT/Mg composite is 3300 times faster than that of the Mg without CNTs due primarily to the galvanic corrosion effect. PMID:26726603

  16. Do Vermont's Floodplains Constitute an Important Source of Labile Carbon?

    Science.gov (United States)

    Perdrial, J. N.; Dolan, A.; Kemsley, M.

    2014-12-01

    Floodplains are extremely heterogeneous landscapes with respect to soil and sediment composition and can present an important source of carbon (C) during floods. For example, stream bank soils and sediments are zones of active erosion and deposition of sediment associated C. Due to the presence of plants, riparian soils contain high amounts of C that is exchanged between stream waters and banks. Abandoned channels and meander wetlands that remain hydrologically connected to the main channel contain high amounts of organic matter that can be flushed into the stream during high discharge. This heterogeneity, result of floodplain geomorphology, land cover and use, can profoundly impact the amount and type of dissolved organic matter (DOM) introduced into streams. In order to assess DOM characteristics leached from heterogeneous floodplain soils, aqueous soil extracts were performed on soil samples representative of different land covers (n=20) at four depths. Extracts were analyzed for dissolved organic C and total dissolved nitrogen with a Shimadzu C analyzer. Colored dissolved organic matter characteristics was measured with the Aqualog Fluorescence Spectrometer and quantified with parallel factor analysis (PARAFAC). Preliminary data from three floodplains in Vermont (Connecticut, Missisquoi and Mad River) show a 3D variability of longitudinal, lateral, and vertical extents on water-extractable, mobile C. Dissolved organic carbon concentrations in meander swamp samples were found up to 9 times higher than in those of soils from agricultural field indicative of an important C source. Although C concentrations in adjacent fields were low, high abundance of labile C (indicated by tryptophan-like fluorescence) in water extracts from fields indicates recent biological production of C. This labile C is easily processed by microbes and transformed to the greenhouse gas CO2. These results provide important information on the contribution and lability of different floodplain

  17. Land use effects on terrestrial carbon sources and sinks

    Institute of Scientific and Technical Information of China (English)

    Josep; G.; Canadell

    2002-01-01

    Current and past land use practices are critical in determining the distribution and size of global terrestrial carbon (C) sources and sinks. Althoughfossil fuel emissions dominate the anthropogenic perturbation of the global C cycle, land use still drives the largest portion of anthropogenic emissions in a number of tropical regions of Asia. The size of the emission flux owing to land use change is still the biggest uncertainty in the global C budget. The Intergovernmental Panel on Climate Change (IPCC) reported a flux term of 1.7 PgC@a-1 for 1990-1995 but more recent estimates suggest the magnitude of this source may be only of 0.96 PgC@a-1 for the 1990s. In addition, current and past land use practices are now thought to contribute to a large degree to the northern hemisphere terrestrial sink, and are the dominant driver for some regional sinks. However, mechanisms other than land use change need to be invoked in order to explain the inferred C sink in the tropics. Potential candidates are the carbon dioxide (CO2) fertilization and climate change; fertilization due to nitrogen (N) deposition is believed to be small or nil. Although the potential for managing C sinks is limited, improved land use management and new land uses such as reforestation and biomass fuel cropping, can further enhance current terrestrial C sinks. Best management practices in agriculture alone could sequester 0.4-0.8 PgC per year in soils if implemented globally. New methodologies to ensure verification and permanency of C sequestration need to be developed.

  18. PRESSURE CHARACTERISTICS OF CAVITATION CONTROL BY AERATION

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-yong; LU Yang-quan; JU Wen-jie; CAI Xin-ming; DING Chun-sheng

    2005-01-01

    This experimental investigation was systematically conducted with the aid of a non-circulating water tunnel in the Hydraulics Laboratory at Zhejiang University of Technology in China.The test velocity is between 20m/s and 40m/s.The least air concentration to prevent cavitation erosion lies between 1.7% and 4.5%.Pressure waveforms with and without aeration in cavitation and cavitation erosion regions were measured.Time-averaged pressure profiles with and without aeration were compared.Pressure characteristics corresponding to least air concentration to prevent cavitation erosion in cavitation and cavitation erosion regions were analyzed.

  19. Acid mine water aeration and treatment system

    Science.gov (United States)

    Ackman, Terry E.; Place, John M.

    1987-01-01

    An in-line system is provided for treating acid mine drainage which basically comprises the combination of a jet pump (or pumps) and a static mixer. The jet pump entrains air into the acid waste water using a Venturi effect so as to provide aeration of the waste water while further aeration is provided by the helical vanes of the static mixer. A neutralizing agent is injected into the suction chamber of the jet pump and the static mixer is formed by plural sections offset by 90 degrees.

  20. Synthesis of Carbon Nanotubes of Few Walls Using Aliphatic Alcohols as a Carbon Source

    Directory of Open Access Journals (Sweden)

    Francisco Espinosa-Magaña

    2013-06-01

    Full Text Available Carbon nanotubes with single and few walls are highly appreciated for their technological applications, regardless of the limited availability due to their high production cost. In this paper we present an alternative process that can lead to lowering the manufacturing cost of CNTs of only few walls by means of the use of the spray pyrolysis technique. For this purpose, ferrocene is utilized as a catalyst and aliphatic alcohols (methanol, ethanol, propanol or butanol as the carbon source. The characterization of CNTs was performed by scanning electron microscopy (SEM and transmission electron microscopy (TEM. The study of the synthesized carbon nanotubes (CNTs show important differences in the number of layers that constitute the nanotubes, the diameter length, the quantity and the quality as a function of the number of carbons employed in the alcohol. The main interest of this study is to give the basis of an efficient synthesis process to produce CNTs of few walls for applications where small diameter is required.

  1. Comparative study on bacterial carbon sources in lake sediments : the role of methanotrophy

    OpenAIRE

    Steger, Kristin; K. Premke; Gudasz, Cristian; Boschker, H.T.S.; Tranvik, Lars J.

    2015-01-01

    Methane-derived carbon can be important in both benthic and pelagic food webs. Either generated in the anaerobic layers of the sediment or in the anaerobic hypolimnion of stratified eutrophic lakes, methane is an excellent carbon source for aerobic methanotrophic bacteria. The very negative methane delta C-13-signal in the methanotrophic biomass provides an excellent opportunity to trace the use of methane-derived carbon in food webs. We studied carbon sources of benthic bacteria in a range o...

  2. Influence of carbon source on the stable carbon isotopic composition of the seagrass Thalassia testudinum

    International Nuclear Information System (INIS)

    The effects of isotopically distinct organic carbon sources in sediments and CO2 enrichment on the stable carbon isotope composition of Thalassia testudinum (turtle grass) seedlings were investigated. Seedling leaves became increasingly 13C depleted in all treatments with time. In the CO2 enriched treatment, δ13C values for seedlings declined from -9.1 to -57.1 per mille over the nine month culture period; the latter value is the lightest stable carbon isotope composition ever reported for a higher plant. In all non-CO2-enriched treatments, δ13C values declined from -9.1 per mille at T=0 to between -18.3 and -22.2 per mille after nine months. The lack of treatment effect in the non-CO2-enriched cultures was probably due to the release and exchange of isotopically light CO2 from the CO2 enriched treatment within the relatively closed environment of the culture room. This exchange was reflected in media dissolved inorganic carbon (DIC) δ13C values that indicated increasing 13C depletion relative to the initial compositions of the synthetic seawater salts. Depletion of 13C in leaf tissue of seedlings in the non-CO2-enriched treatments occurred faster than did media DIC 13C depletion, suggesting an increase in isotopic fractionation as seedlings grew. The reasons for this increasing fractionation are unclear, but they may reflect a decreasing contribution of isotopically heavy seed research and/or increasing availability of exogenous carbon. 18 refs, 1 fig., 2 tabs

  3. Shear reinforced beams in autoclaved aerated concrete

    DEFF Research Database (Denmark)

    Cornelius, Thomas

    2010-01-01

    Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different combinat...

  4. Soil Aeration Variability as Affected by Reoxidation

    Institute of Scientific and Technical Information of China (English)

    A.WOLI(N)SKA; Z.ST(E)PNIEWSKA

    2013-01-01

    The interplay between soil physical parameters during the recovery from anoxic stresses (reoxidation) is largely unrecognized.This study was conducted to characterise the soil aeration status and derive correlations between variable aeration factors during reoxidation.Surface layers (0-30 cm) of three soil types,Haplic Phaeozem,Mollic Gleysol,and Eutric Cambisol (FAO soil group),were selected for analysis.The moisture content was determined for a range of pF values (0,1.5,2.2,2.7,and 3.2),corresponding to the available water for microorganisms and plant roots.The variability of a number of soil aeration parameters,such as water potential (pF),air-filled porosity (Eg),oxygen diffusion rate (ODR),and redox potential (Eh),were investigated.These parameters were found to be interrelated in most cases.There were significant (P < 0.001) negative correlations of pF,Eg,and ODR with Eh.A decrease in water content as a consequence of soil reoxidation was manifested by an increase in the values of aeration factors in the soil environment.These results contributed to understanding of soil redox processes during recovery from flooding and might be useful for development of agricultural techniques aiming at soil reoxidation and soil fertility optimisation.

  5. Size distributions, sources and source areas of water-soluble organic carbon in urban background air

    Directory of Open Access Journals (Sweden)

    H. Timonen

    2008-04-01

    Full Text Available This paper represents the results of one year long measurement period of the size distributions of water-soluble organic carbon (WSOC, inorganic ions and gravimetric mass of particulate matter. Measurements were done at an urban background station (SMEAR III by using a micro-orifice uniform deposit impactor (MOUDI. The site is located in northern European boreal region in Helsinki, Finland. The WSOC size distribution measurements were completed with the chemical analysis of inorganic ions, organic carbon (OC and monosaccharide anhydrides from the filter samples. During the measurements gravimetric mass in the MOUDI collections varied between 3.4 and 55.0 μg m−3 and the WSOC concentration was between 0.3 and 7.4 μg m−3. On average, water-soluble particulate organic matter (WSPOM, WSOC multiplied by 1.6 comprised 25±7.7% and 7.5±3.4% of aerosol PM1 mass and the PM1−10 mass, respectively. Inorganic ions contributed 33±12% and 28±19% of the analyzed PM1 and PM1−10 aerosol mass.

    Five different aerosol categories corresponding to different sources or source areas were identified (long-range transport aerosols, biomass burning aerosols from wild land fires and from small-scale wood combustion, aerosols originating from marine areas and from the clean arctic areas. Clear differences in WSOC concentrations and size distributions originating from different sources or source areas were observed, although there are also many other factors which might affect the results. E.g. the local conditions and sources of volatile organic compounds (VOCs and aerosols as well as various transformation processes are likely to have an impact on the measured aerosol composition. Using the source categories, it was identified that especially the oxidation products of biogenic VOCs in summer had a clear effect on WSOC concentrations.

  6. Tracing the sources of organic carbon in freshwater systems

    Science.gov (United States)

    Glendell, Miriam; Meersmans, Jeroen; Barclay, Rachel; Yvon-Durocher, Gabriel; Barker, Sam; Jones, Richard; Hartley, Iain; Dungait, Jennifer; Quine, Timothy

    2016-04-01

    both terrestrial and aquatic sources as recorded in lake sediments to the measured rates of soil erosion and terrestrial & aquatic CO2 respiration rates, this study has paved a way towards a novel and cross-disciplinary approach to investigate and further improve current status of knowledge as regards C-cycling across the entire terrestrial-aquatic continuum. 137Cs was found to be useful to understand the dynamics and spatial pattern of lateral fluxes of sediment & C at the catchment scale, while tracing chemical composition of C using n-alkanes and stable isotopes (δ13C, δ15N) allowed distinguishing between the terrestrial vs. aquatic origin of C and determining main sources of particulate organic carbon in the aquatic environment within the two study catchments.

  7. Evaluation of oxygen transfer parameters of fine-bubble aeration system in plug flow aeration tank of wastewater treatment plant

    Institute of Scientific and Technical Information of China (English)

    Xiaohong Zhou; Yuanyuan Wu; Hanchang Shi; Yanqing Song

    2013-01-01

    Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant (WWTP) is meaningful for the optimization of WWTP,however,scarce to best of our knowledge.Through analyzing a plug flow aeration tank in the Lucun WWTP,in Wuxi,China,the oxygenation capacity of fine-bubble aerators under process conditions have been measured insitu using the off-gas method and the non-steady-state method.The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP had significantly different oxygen transfer performance; furthermore,the aerators in the same corridor shared almost equal oxygen transfer performance over the course of a day.Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water.The loss of oxygen transfer coefficient was over 50% under low-aeration conditions (aeration amount < 0.67 Nm3/hr).However,as the aeration amount reached 0.96 Nm3/hr,the discrepancy of oxygen transfer between the process condition and clean water was negligible.The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.

  8. Development of a water purification system via enhanced aeration 1. Phenomenological characteristics of the aeration system

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, M.; Nonaka, M. [Tokyo Univ. (Japan)

    1998-07-25

    An enormous number of industrial and municipal waste materials should directly and indirectly enhance the environmental pollution in rivers, lakes and reservoirs. The change of the human life style is also another important factor affecting on the pollution of water environments. One of the most effective and economical ways to conserve, improve and purity the water environment should be the enhancement of the dissolved oxygen concentration by aeration. In this study, an enhanced aeration system is developed to cope with low efficiency, scale-up difficulty and restricted versatility accompanied with conventional aeration systems. The developed aeration system utilizes the centrifugal shear stress to generate an enormous number of fine air bubbles and to establish the high propagation performance of mixing energy. The pressure loss of the cyclone-like aerator is deduced from the dimensional analysis and experimental works, which serves to scale up the aeration system and to evaluate the energy consumption of the whole system. 14 refs., 10 figs., 1 tab.

  9. Compilation of carbon-14 data

    International Nuclear Information System (INIS)

    A review and critical analysis was made of the original sources of carbon-14 in the graphite moderator and reflector zones of the eight Hanford production reactors, the present physical and chemical state of the carbon-14, pathways (other than direct combustion) by which the carbon-14 could be released to the biosphere, and the maximum rate at which it might be released under circumstances which idealistically favor the release. Areas of uncertainty are noted and recommendations are made for obtaining additional data in three areas: (1) release rate of carbon-14 from irradiated graphite saturated with aerated water; (2) characterization of carbon-14 deposited outside the moderator and reflector zones; and (3) corrosion/release rate of carbon-14 from irradiated steel and aluminum alloys

  10. Carbon nanotube based field emission X-ray sources

    Science.gov (United States)

    Cheng, Yuan

    This dissertation describes the development of field emission (FE) x-ray sources with a carbon-nanotube (CNT) cathode. Field emission x-rays have advantages over conventional x-rays by replacing the thermionic cathode with a cold cathode so that electrons are emitted at room temperature and emission is voltage controllable. CNTs are found to be excellent electron emitters with low threshold fields and high current density which makes them ideal for generate field emission x-rays. Macroscopic CNT cold cathodes are prepared and the parameters to tune their field emission properties are studied: structure and morphology of CNT cathodes, temperature as well as electronic work function of CNT. Macroscopic CNT cathodes with optimized performance are chosen to build a high-resolution x-ray imaging system. The system can readily generate x-ray radiation with continuous variation of temporal resolution up to nanoseconds and spatial resolution down to 10 micron. Its potential applications for dynamic x-ray imaging and micro-computed tomography are also demonstrated. The performance characteristics of this compact and versatile system are promising for non-destructive testing and for non-invasive small-animal imaging for biomedical research.

  11. Source apportionment of PM10 mass and particulate carbon in the Kathmandu Valley, Nepal

    Science.gov (United States)

    Kim, Bong Mann; Park, Jin-Soo; Kim, Sang-Woo; Kim, Hyunjae; Jeon, Haeun; Cho, Chaeyoon; Kim, Ji-Hyoung; Hong, Seungkyu; Rupakheti, Maheswar; Panday, Arnico K.; Park, Rokjin J.; Hong, Jihyung; Yoon, Soon-Chang

    2015-12-01

    The Kathmandu Valley in Nepal is a bowl-shaped urban basin in the Himalayan foothills with a serious problem of fine particulate air pollution that impacts local health and impairs visibility. Particulate carbon concentrations have reached severe levels that threaten the health of 3.5 million local residents. Moreover, snow and ice on the Himalayan mountains are melting as a result of additional warming due to particulate carbon, especially high black carbon concentrations. To date, the sources of the Valley's particulate carbon and the impacts of different sources on particulate carbon concentrations are not well understood. Thus, before an effective control strategy can be developed, these particulate carbon sources must be identified and quantified. Our study has found that the four primary sources of particulate carbon in the Kathmandu Valley during winter are brick kilns, motor vehicles, fugitive soil dust, and biomass/garbage burning. Their source contributions are quantified using a recently developed new multivariate receptor model SMP. In contrast to other highly polluted areas such as China, secondary contribution is almost negligible in Kathmandu Valley. Brick kilns (40%), motor vehicles (37%) and biomass/garbage burning (22%) have been identified as the major sources of elemental carbon (black carbon) in the Kathmandu Valley during winter, while motor vehicles (47%), biomass/garbage burning (32%), and soil dust (13%) have been identified as the most important sources of organic carbon. Our research indicates that controlling emissions from motor vehicles, brick kilns, biomass/garbage burning, and soil dust is essential for the mitigation of the particulate carbon that threatens public health, impairs visibility, and influences climate warming within and downwind from the Kathmandu Valley. In addition, this paper suggests several useful particulate carbon mitigation methods that can be applied to Kathmandu Valley and other areas in South Asia with

  12. Examining the Role of Multiple Carbon Sources in Isoprene Synthesis in Plants Using Stable Isotope Techniques

    Science.gov (United States)

    Funk, J. L.; Mak, J. E.; Lerdau, M. T.

    2001-12-01

    The carbon source for phytogenc isoprene is an issue with important ramifications for both atmospheric and biological science because of its impact on the isotopic signature of isoprene and its oxidation products and because it lends insight into the function that isoprene serves within leaves. Although recently assimilated carbon is believed to be the primary carbon source for isoprene production in plants, variation in diurnal and seasonal isoprene fluxes that cannot be explained by temperature, light, and leaf development have led to the suggestion that alternative carbon sources may contribute. Stable isotopes of carbon can be used to identify changes in carbon partitioning into isoprene synthesis, and mixing models can assess the relative importance of each source. In preliminary studies, we document an additional 8-10 \\permil discrimination in isoprene emitted in the absence of photosynthesis. This change in signature suggests that the carbon source is switched from recently obtained photosynthate to a source more depleted in 13C. We propose that intermediates from carbohydrate degradation and/or re-fixation of CO2 from mitichondrial respiration and photorespiration can contribute to isoprene production. In addition, we expect alternative carbon sources to be most important when photosynthate is limiting (e.g. during water stress events). Photosynthesis, respiration, and isoprene emission measurements are used to calculate the isotopic signatures of the three potential carbon pools: photosynthate derived from ambient CO2, photosynthate derived from respired CO2, and carbohydrate-derived intermediates.

  13. Young organic matter as a source of carbon dioxide outgassing from Amazonian rivers

    Energy Technology Data Exchange (ETDEWEB)

    Mayorga, E; Aufdenkampe, A K; Masiello, C A; Krusche, A V; Hedges, J I; Quay, P D; Richey, J E; Brown, T A

    2005-06-23

    Rivers are generally supersaturated with respect to carbon dioxide, resulting in large gas evasion fluxes that can be a significant component of regional net carbon budgets. Amazonian rivers were recently shown to outgas more than ten times the amount of carbon exported to the ocean in the form of total organic carbon or dissolved inorganic carbon. High carbon dioxide concentrations in rivers originate largely from in situ respiration of organic carbon, but little agreement exists about the sources or turnover times of this carbon. Here we present results of an extensive survey of the carbon isotope composition ({sup 13}C and {sup 14}C) of dissolved inorganic carbon and three size-fractions of organic carbon across the Amazonian river system. We find that respiration of contemporary organic matter (less than 5 years old) originating on land and near rivers is the dominant source of excess carbon dioxide that drives outgassing in mid-size to large rivers, although we find that bulk organic carbon fractions transported by these rivers range from tens to thousands of years in age. We therefore suggest that a small, rapidly cycling pool of organic carbon is responsible for the large carbon fluxes from land to water to atmosphere in the humid tropics.

  14. Influence of carbon source on alpha-amylase production by Aspergillus oryzae

    DEFF Research Database (Denmark)

    Carlsen, Morten; Nielsen, Jens

    2001-01-01

    The influence of the carbon source on a-amylase production by Aspergillus oryzae was quantified in carbon-limited chemostat cultures. The following carbon sources were investigated: maltose, maltodextrin (different chain lengths), glucose, fructose, galactose, sucrose, glycerol, mannitol and...... acetate. A. oryzae did not grow on galactose as the sole carbon source, but galactose was co-metabolized together with glucose. Relative to that on low glucose concentration (below 10 mg/l), productivity was found to be higher during growth on maltose and maltodextrins, whereas it was lower during growth...

  15. Effect of carbon dioxide and bicarbonate as inorganic carbon sources on growth and adaptation of autohydrogenotrophic denitrifying bacteria

    International Nuclear Information System (INIS)

    Acclimation of autohydrogenotrophic denitrifying bacteria using inorganic carbon source (CO2 and bicarbonate) and hydrogen gas as electron donor was performed in this study. In this regard, activated sludge was used as the seed source and sequencing batch reactor (SBR) technique was applied for accomplishing the acclimatization. Three distinct strategies in feeding of carbon sources were applied: (I) continuous sparging of CO2, (II) bicarbonate plus continuous sparging of CO2, and (III) only bicarbonate. The pH-reducing nature of CO2 showed an unfavorable impact on denitrification rate; however bicarbonate resulted in a buffered environment in the mixed liquor and provided a suitable mean to maintain the pH in the desirable range of 7-8.2. As a result, bicarbonate as the only carbon source showed a faster adaptation, while carbon dioxide as the only carbon source as well as a complementary carbon source added to bicarbonate resulted in longer acclimation period. Adapted hydrogenotrophic denitrifying bacteria, using bicarbonate and hydrogen gas in the aforementioned pH range, caused denitrification at a rate of 13.33 mg NO3--N/g MLVSS/h for degrading 20 and 30 mg NO3--N/L and 9.09 mg NO3--N/g MLVSS/h for degrading 50 mg NO3--N/L

  16. The Effect of Carbon Source and Fluoride Concentrations in the "Streptococcus Mutans" Biofilm Formation

    Science.gov (United States)

    Paulino, Tony P.; Andrade, Ricardo O.; Bruschi-Thedei, Giuliana C. M.; Thedei, Geraldo, Jr.; Ciancaglini, Pietro

    2004-01-01

    The main objective of this class experiment is to show the influence of carbon source and of different fluoride concentrations on the biofilm formation by the bacterium "Streptococcus mutans." The observation of different biofilm morphology as a function of carbon source and fluoride concentration allows an interesting discussion regarding the…

  17. Evaluation of an Industrial Byproduct Glycol Mixture as a Carbon Source for Denitrification

    OpenAIRE

    Liang, Wei

    2013-01-01

    In order to meet increasingly stringent total nitrogen limits, supplemental carbon must be added to improve the performance of the biological nutrient removal process. An industrial by-product that contained ethylene glycol and propylene glycol was used as a substitute carbon source for methanol in this study. The objectives of this study were to investigate the efficiency of using the glycol mixture as carbon source, including the calculation of denitrification rate and yield at two differen...

  18. Investigating effectiveness of activated carbons of natural sources on various supercapacitors

    Science.gov (United States)

    Faisal, Md. Shahnewaz Sabit; Rahman, Muhammad M.; Asmatulu, Ramazan

    2016-04-01

    Activated carbon can be produced from natural sources, such as pistachio and acorn shells, which can be an inexpensive and sustainable sources of natural wastes for the energy storage devices, such as supercapacitors. The carbonaceous materials used in this study were carbonized at the temperatures of 700°C and 900°C after the stabilization process at 240°C for two hours. These shells showed approximately 60% carbon yield. Carbonized nutshells were chemically activated using1wt% potassium hydroxide (KOH). Activated carbon powders with polyvinylidene fluoride (PVdF) were used to construct carbon electrodes. A 1M of tetraethylammonium tetrafluoroborate (TEABF4) and propylene carbonate (PC) were used as electrolytes. Electrochemical techniques, such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for the characterization of the supercapacitors. Scanning electron microscopy (SEM) was used to inspect the surface texture of the activated carbons. Activated pistachio shells carbonized at 700°C showed more porous surface texture than those carbonized at 900°C. Effects of the carbonization temperatures were studied for their electrochemical characteristics. The shells carbonized at 700°C showed better electrochemical characteristics compared to those carbonized at 900°C. The test results provided about 27,083 μF/g specific capacitance at a scan rate of 10mV/s. This study showed promising results for using these activated carbons produced from the natural wastes for supercapacitor applications.

  19. Comparative study on bacterial carbon sources in lake sediments: the role of methanotrophy

    OpenAIRE

    Steger, K.; K. Premke; Gudasz, C.; Boschker, H.T.S.; Tranvik, L.J.

    2015-01-01

    Methane-derived carbon can be important in both benthic and pelagic food webs.Either generated in the anaerobic layers of the sediment or in the anaerobic hypolimnion of stratifiedeutrophic lakes, methane is an excellent carbon source for aerobic methanotrophic bacteria.The very negative methane d13C-signal in the methanotrophic biomass provides an excellentopportunity to trace the use of methane-derived carbon in food webs. We studied carbon sourcesof benthic bacteria in a range of Swedish l...

  20. Boreal Lake Sediments as Sources and Sinks of Carbon

    OpenAIRE

    Gudasz, Cristian

    2011-01-01

    Inland waters process large amounts of organic carbon, contributing to CO2 and CH4 emissions, as well as storing organic carbon (OC) over geological timescales. Recently, it has been shown that the magnitude of these processes is of global significance. It is therefore important to understand what regulates OC cycling in inland waters and how is that affected by climate change. This thesis investigates the constraints on microbial processing of sediment OC, as a key factor of the carbon cycli...

  1. Radon in water aeration system operational performance

    International Nuclear Information System (INIS)

    North East Environmental Products, Inc. is a manufacturer of residential scale aeration systems for removal of radon and volatile organic chemicals from private water supplies. This paper is a review of the operational history of residential scale point of entry (POE) radon aeration systems. Emphasis is placed on the difficulties and solutions encountered in actual installations caused by both mechanical difficulties and water quality parameters. A summary of radon reduction efficiency is presented for wells with radon concentrations from 21,000 to 2,600,000 pCi/L. A discussion of customer concerns and attitudes is presented along with other areas for further technical improvement. Training techniques for dealers and installers are also discussed. An update of the current status of the radon in water industry includes current sales volumes as compared to the potential market and an update on the radon in water MCL standard setting process from an industry perspective

  2. Application of plant carbon source for denitrification by constructed wetland and bioreactor: review of recent development.

    Science.gov (United States)

    Hang, Qianyu; Wang, Haiyan; Chu, Zhaosheng; Ye, Bibi; Li, Chunmei; Hou, Zeying

    2016-05-01

    Water quality standard for nitrate becomes more and more strict, and the plant carbon source is widely used for denitrification by constructed wetland (CW) and bioreactor. However, the nitrate removal efficiency by different types of plant carbon source are not evaluated comprehensively. Denitrification performance of different plant carbon sources, and the influence of dosing method and pretreatment are thoroughly reviewed in this paper, which aims to investigate the accurate utilization of plant carbon source for nitrogen (as nitrate) removal. It is concluded that plant carbon source addition for all types of CWs and bioreactors can improve the nitrate removal efficiency to some extent, and the dosing method of plant carbon source for denitrification should be further studied and optimized in the future. The popular carbon sources for CW and bioreactor denitrification enhancement are woodchip, chopped macrophytes, crop plants, macrophytes litters, etc. The recommended optimum C:N ratios for CW and bioreactor are 4.0:5.0 and 1.8:3.0, respectively. The physical and biological pretreatments are selected to supply organic carbon for long-term denitrification. PMID:26971521

  3. CFD model of an aerating hydrofoil

    International Nuclear Information System (INIS)

    Improving water quality in the tailrace below hydroelectric dams has become a priority in many river systems. In warm climates, water drawn by the turbine from deep in a reservoir can be deficient in dissolved oxygen (DO), a critical element in maintaining a healthy aquatic ecosystem. Many different solutions have been proposed in order to increase the DO levels in turbine discharge, including: turbine aeration systems (adding air to the water through either the turbine hub, the periphery or through distributed aeration in the runner blades); bubble diffusers in the reservoir or in the tailrace; aerating weirs downstream of the dams; and surface water pumps in the reservoir near the dam. There is a significant potential to increase the effectiveness of these solutions by improving the way that oxygen is introduced into the water; better distributions of bubbles will result in better oxygen transfer. In the present study, a two-phase Computational Fluid Dynamics model has been formulated using a commercial code to study the distribution of air downstream of a simple aerating hydrofoil. The two-phase model uses the Eulerian-Eulerian approach. Appropriate relations are used to model the interphase forces, including the Grace drag force model, the Favre averaged drag force and the Sato enhanced eddy viscosity. The model is validated using experimental results obtained in the water tunnel at the University of Minnesota's Saint Anthony Falls Laboratory. Results are obtained for water velocities between 5 and 10 m/s, air flow rates between 0.5 and 1.5 sL/min and for angles of attack between 0° and -8°. The results of this study show that the CFD model provides a good qualitative comparison to the experimental results by well predicting the wake location at the different flow rates and angles of attack used

  4. Aeration and hydrodynamics in submerged membrane bioreactors

    OpenAIRE

    Braak, Etienne; Alliet-Gaubert, Marion; Schetrite, Sylvie; Albasi, Claire

    2011-01-01

    Membrane bioreactor (MBR) is already a well-developed wastewater treatment process for both municipal and industrial applications. Nonetheless, membrane fouling remains a significant problem for its wider development. In the case of submerged membrane bioreactors (SMBRs), one of the most efficient strategies to limit fouling is the use of a gas/liquid two-phase flow to enhance the mass transfer. However, the effect of aeration still remains incompletely understood. The complexity ...

  5. Cavity filling water control below aerator devices

    Institute of Scientific and Technical Information of China (English)

    钱尚拓; 吴建华; 马飞; 徐建荣; 彭育; 汪振

    2014-01-01

    With the rapid development of high dam projects within China, the dragon-drop-tail spillway tunnel is introduced and widely used. In view of the high water head and the large flow velocity on the dragon-drop-tail section, aerator devices are usually placed for the cavitation damage control. For the device placed in its initial position, it is a serious concern to design a suitable flow regime of the cavity and to control the cavity filling water due to the large flow depth and the low Froude number through this aera-tor. In this study, the relationships between the geometries of the aerator device and the jet impact angle of the lower trajectory of the flow are theoretically analyzed with/without a local slope. Nine test cases with different geometries are designed, the effectiveness of the filling water control is experimentally investigated under different operation conditions, and two criteria of the local slope design are proposed. It is concluded that the cavity flow regime and the filling water can be improved if a small impact angle and some sui-table geometries of the local slope are designed.

  6. Food sources for the mangrove tree crab aratus pisonii: a carbon isotopic study

    International Nuclear Information System (INIS)

    Muscle tissues from the mangrove tree crab Aratus pisonii was analysed for carbon isotopic composition, in order to trace its major food sources. Potential food sources: mangrove leaves epi phytic green algae, mangrove sediments and open water and mangrove suspended matter; were also analysed. The results show that A. pisonii is basically omnivorous, with major food sources from marine origin. However, mangrove carbon can contribute with 16% to 42% in the crab's diet. (author)

  7. Power source life cycle assessment by the Bilan Carbone method

    International Nuclear Information System (INIS)

    Bilan Carbone is a method to assess the amount of spent energy in the form of CO2 formation and its impacts on climate change (carbon footprint). The method assesses each steps in power production, finds hidden energy flows for modelling future energy scenarios. The principles of the method are outlined and an example of its application is presented. (orig.)

  8. Electrochemical Oxidation Using BDD Anodes Combined with Biological Aerated Filter for Biotreated Coking Wastewater Treatment

    OpenAIRE

    Wang, C.R.; Hou, Z. F.; M. R. Zhang; J. Qi; Wang, J.

    2015-01-01

    Coking wastewater is characterized by poor biodegradability and high microorganism toxicity. Thus, it is difficult to meet Grade I of Integrated Wastewater Discharge Standard of China by biological treatment technology; specifically, COD cannot meet above standard due to containing refractory organics. A novel coupling reactor, electrochemical oxidation using BDD anodes and biological aerated filter (BAF), has been developed for carbon and nitrogen removal from biotreated coking wastewater, f...

  9. Dissolved black carbon in Antarctic lakes: Chemical signatures of past and present sources

    Science.gov (United States)

    Khan, Alia L.; Jaffé, Rudolf; Ding, Yan; McKnight, Diane M.

    2016-06-01

    The perennially ice-covered, closed-basin lakes in the McMurdo Dry Valleys, Antarctica, serve as sentinels for understanding the fate of dissolved black carbon from glacial sources in aquatic ecosystems. Here we show that dissolved black carbon can persist in freshwater and saline surface waters for thousands of years, while preserving the chemical signature of the original source materials. The ancient brines of the lake bottom waters have retained dissolved black carbon with a woody chemical signature, representing long-range transport of black carbon from wildfires. In contrast, the surface waters are enriched in contemporary black carbon from fossil fuel combustion. Comparison of samples collected 25 years apart from the same lake suggests that the enrichment in anthropogenic black carbon is recent. Differences in the chemical composition of dissolved black carbon among the lakes are likely due to biogeochemical processing such as photochemical degradation and sorption on metal oxides.

  10. Wetlands as a large carbon source for inland waters

    Science.gov (United States)

    Abril, Gwenaël; Martinez, Jean-Michel; Artigas, L. Felipe; Moreira-Turcq, Patricia; Benedetti, Marc F.; Vidal, Luciana; Meziane, Tarik; Kim, Jung-Hyun; Bernardes, Marcelo C.; Deborde, Jonathan; Lima Souza, Edivaldo; Albéric, Patrick; Landim de Souza, Marcelo F.; Roland, Fabio

    2014-05-01

    Recent estimates suggests that up to 3 PgC y-1 could be emitted as CO2 from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon previously fixed upstream by land plant photosynthesis and subsequently transported downstream with runoff. But the observed carbon fluxes from first-order streams do not account for all of the CO2 outgassing at the scale of entire watersheds. Three-quarters of the world's flooded land are temporary wetlands. However, the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Based on observations in rivers and floodplains of the central Amazon, we suggest that wetlands pump large amounts of atmospheric CO2 into river waters. Indeed, the magnitude of CO2 outgassing in Amazonian waters is spatially and temporally related to their connection with the semi-aquatic vegetation that performs aerial photosynthesis (Flooded forests and floating macrophytes). These wetlands export half of their gross primary production to waters as dissolved CO2 and organic carbon, compared to only a few percent of gross primary production in upland ecosystems. Global carbon budgets should explicitly address temporary or vegetated flooded areas, as these ecosystems combine high aerial primary production with a large and fast carbon export capacity, potentially supporting a significant fraction of CO2 evasion from inland waters.

  11. Inverse problem of bottom slope design for aerator devices

    Institute of Scientific and Technical Information of China (English)

    吴建华; 樊博; 许唯临

    2013-01-01

    Air entrainment is an effective approach to protect release works from cavitation damage. The traditional method of aera-tor device designs is that, for given flow conditions, the geometries of the aerator device are designed and then the effects are experi-mentally tested for cavitation damage control. The present paper proposes an inverse problem method of determining the bottom slopes in front of and behind an aerator if the requirements of air entrainment, flow conditions and some of aerator geometric para-meters are given. An RBF neural network model is developed and the relevant bottom slopes are calculated in different conditions of flow and geometry on the basis of the data of 19 aerator devices from different discharge tunnels with safe operation. The case study shows that the methodology provides an effective way to design aerator devices under given target conditions.

  12. Production of Feruloyl Esterase from Aspergillus niger by Solid-State Fermentation on Different Carbon Sources

    Directory of Open Access Journals (Sweden)

    Shiyi Ou

    2011-01-01

    Full Text Available A mixture of wheat bran with maize bran as a carbon source and addition of (NH4SO4 as nitrogen source was found to significantly increase production of feruloyl esterase (FAE enzyme compared with wheat bran as a sole carbon and nitrogen source. The optimal conditions in conical flasks were carbon source (30 g to water 1 : 1, maize bran to wheat bran 1 : 2, (NH4SO4 1.2 g and MgSO4 70 mg. Under these conditions, FAE activity was 7.68 mU/g. The FAE activity on the mixed carbon sources showed, high activity against the plant cell walls contained in the cultures.

  13. Modeling enzyme production with Aspergillus oryzae in pilot scale vessels with different agitation, aeration, and agitator types

    DEFF Research Database (Denmark)

    Albæk, Mads Orla; Gernaey, Krist; Hansen, Morten S.;

    2011-01-01

    tank reactors. Different conditions of agitation and aeration were employed as well as two different impeller geometries. The limiting factor for the productivity was oxygen supply to the fermentation broth, and the carbon substrate feed flow rate was controlled by the dissolved oxygen tension. In...

  14. Terrestrial sources and sinks of carbon inferred from terrestrial data

    OpenAIRE

    Houghton, R. A.

    2011-01-01

    Two approaches have been used to calculate changes in terrestrial carbon storage with data obtained from terrestrial ecosystems, rather than with atmospheric or oceanographic data. One approach is based on the changes in carbon that result from changes in land use (conversion of forest to agricultural land, abandonment of agricultural land, harvest and regrowth). The other approach uses measurements of forest biomass obtained through forests inventories to determine change directly. These lat...

  15. Carbon source from the toroidal pumped limiter during long discharge operation in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Dufour, E.; Brosset, C.; Lowry, C.; Bucalossi, J.; Chappuis, P.; Corre, Y.; Desgranges, C.; Guirlet, R.; Gunn, J.; Loarer, T.; Mitteau, R.; Monier-Garbet, P.; Pegourie, B.; Reichle, R.; Thomas, P.; Tsitrone, E. [Association EURATOM-CEA, CEA/DSM/DRFC, CEA-Cadarache, 13 - St Paul-lez-Durance (France); Hogan, J. [Oak Ridge National Laboratory, 2 Fusion Energy Division, Oak Ridge, TN (United States); Roubin, P.; Martin, C.; Arnas, C. [CNRS-Universite de Provence, LPIIM, UMR 6633, 13 - Marseille (France)

    2005-07-01

    A better understanding of deuterium retention mechanisms requires the knowledge of carbon sources in Tore-Supra. The main source of carbon in the vacuum vessel during long discharges is the toroidal pumped limiter (TPL). This work is devoted to the experimental characterisation of the carbon source from the TPL surface during long discharges using a visible spectroscopy diagnostic. Moreover, we present an attempt to perform a carbon balance over a typical campaign and we discuss it with regards to the deuterium in-vessel inventory deduced from particle balance and the deuterium content of the deposited layers. The study shows that only a third of the estimated deuterium trapped in the vessel is trapped in the carbon deposits. Thus, in the present state of our knowledge and characterisation of the permanent retention, one has to search for mechanisms other than co-deposition to explain the deuterium retention in Tore Supra. (A.C.)

  16. Treatment of hydroponic wastewater by denitrification filters using plant prunings as the organic carbon source.

    Science.gov (United States)

    Park, J B K; Craggs, R J; Sukias, J P S

    2008-05-01

    This study investigated the feasibility of using pre-treated plant liquors as organic carbon sources for the treatment of hydroponic wastewater containing high nitrate-N (>300 mg N/L). The waste plant material was pre-treated to extract organic carbon-rich liquors. When this plant liquor was used as an organic carbon source in denitrification filters at the organic carbon:nitrogen dose rate of 3C:N, nitrate removal efficiencies were >95% and final effluent nitrate concentrations were consistently 140 mg/L) of organic carbon (fBOD5) remained in the final effluents. Therefore, a 'compromise' organic carbon:nitrogen dose rate (2C:N) was trialled, at which nitrate removal efficiencies were maintained at >85%, final effluent nitrate concentrations were consistently below 45 mg N/L, and effluent fBOD5 concentrations were hydroponic wastewater in a denitrification filter. PMID:17714940

  17. Food sources and carbon dudget of chinese prawn Penaeus chinensis

    Science.gov (United States)

    Dong, Shuang-Lin; Zhang, Shuo; Wang, Fang

    2002-03-01

    This study deals with contribution of artificial food pellet and natural food to Chinese prawn ( Penaeus orientalis) growth in a semi-intensive culture pond. The prawn carbon consumption, budget, and the effects of some factors on the budget were investigated. The results showed that 26.2% of P. orientalis growth carbon came from formulated feed at the initial culture stage (when the prawns were 0.06±0.01 g in wet weight), and was 62.5% when the prawns were 9.56±1.04 g. The remaining part of the growth carbon was derived from organic fertilizer and natural food. The highest growth rate occurred at 20×10-3 salinity. Suitable salinity for culturing Chinese prawn was (20 28)×10-3.

  18. FOOD SOURCES AND CARBON BUDGET OF CHINESE PRAWN PENAEUS CHINENSIS

    Institute of Scientific and Technical Information of China (English)

    董双林; 张硕; 王芳

    2002-01-01

    This study deals with contribution of artificial food pellet and natural food to Chinese prawn (Penaeus orientalis) growth in a semiintensive culture pond. The prawn carbon consumption, budget, and the effects of some factors on the budget were investigated. The results showed that 26.2% of P. orientalis growth carbon came from formulated feed at the initial culture stage (when the prawns were 0.06±0.01 g in wet weight), and was 62.5% when the prawns were 9.56±1.04 g. The remaining part of the growth carbon was derived from organic fertilizer and natural food. The highest growth rate occurred at 20×10-3 salinity. Suitable salinity for culturing Chinese prawn was (20-28)×10-3.

  19. Nitrate Removal from Drinking Water with Sodium Citrate as Sole Carbon Source

    Institute of Scientific and Technical Information of China (English)

    YAN Bo; ZHAO Lin; TAN Xin

    2005-01-01

    This paper investigates the effect of using sodium citrate(NaC6H5O6*2H2O)as sole carbon source for nitrate removal from drinking water.With sodium citrate as sole carbon source, batch experiments have been conducted to study the law of denitrification influenced by pH, C/N and temperature. Results show that a denitrification rate reaching 1.32 g NO-3-N /(g Biomass*d) was obtained when pH was at 7.5,C/N at 1.7(atom ratio), and temperature from 20 ℃ to 30 ℃. The results also show that denitrification rate with sodium citrate as carbon source approaches to that with methanol as carbon source.

  20. Microarray analysis of Neosartorya fischeri using different carbon sources, petroleum asphaltenes and glucose-peptone

    Directory of Open Access Journals (Sweden)

    Edna L. Hernández-López

    2015-09-01

    Here we describe experimental procedures and methods about our dataset (NCBI GEO accession number GSE68146 and describe the data analysis to identify different expression levels in N. fischeri using this recalcitrant carbon source.

  1. Review: role of carbon sources for in vitro plant growth and development.

    Science.gov (United States)

    Yaseen, Mehwish; Ahmad, Touqeer; Sablok, Gaurav; Standardi, Alvaro; Hafiz, Ishfaq Ahmad

    2013-04-01

    In vitro plant cells, tissues and organ cultures are not fully autotrophic establishing a need for carbohydrates in culture media to maintain the osmotic potential, as well as to serve as energy and carbon sources for developmental processes including shoot proliferation, root induction as well as emission, embryogenesis and organogenesis, which are highly energy demanding developmental processes in plant biology. A variety of carbon sources (both reducing and non-reducing) are used in culture media depending upon genotypes and specific stages of growth. However, sucrose is most widely used as a major transport-sugar in the phloem sap of many plants. In micropropagation systems, morphogenetic potential of plant tissues can greatly be manipulated by varying type and concentration of carbon sources. The present article reviews the past and current findings on carbon sources and their sustainable utilization for in vitro plant tissue culture to achieve better growth rate and development. PMID:23212616

  2. Quasi-steady carbon plasma source for neutral beam injector

    International Nuclear Information System (INIS)

    Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ∼3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration

  3. Quasi-steady carbon plasma source for neutral beam injector.

    Science.gov (United States)

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2014-02-01

    Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ∼3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration. PMID:24593646

  4. Theoretical study on the carbon nanotube used ashard x—radiation source

    Institute of Scientific and Technical Information of China (English)

    LuJing-Han; QinXi-Jun

    1998-01-01

    Calculations and analyses are made on the interaction between the carbon nanotube and the incident positron of high energy.The results obtained show that it is possible to use carbon nanotube as hard X-radiation source with high intensity and good monochromaticity.

  5. Comparative study on bacterial carbon sources in lake sediments: the role of methanotrophy

    NARCIS (Netherlands)

    Steger, K.; Premke, K.; Gudasz, C.; Boschker, H.T.S.; Tranvik, L.J.

    2015-01-01

    Methane-derived carbon can be important in both benthic and pelagic food webs.Either generated in the anaerobic layers of the sediment or in the anaerobic hypolimnion of stratifiedeutrophic lakes, methane is an excellent carbon source for aerobic methanotrophic bacteria.The very negative methane d13

  6. Sources of uncertainties in modelling black carbon at the global scale

    NARCIS (Netherlands)

    Vignati, E.; Karl, M.; Krol, M.C.; Wilson, J.; Stier, P.; Cavalli, F.

    2010-01-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in th

  7. Tracing organic matter sources of estuarine tidal flat nematodes with stable carbon isotopes

    NARCIS (Netherlands)

    Moens, T.; Luyten, C.; Middelburg, J.J.; Herman, P.M.J.; Vincx, M.

    2002-01-01

    The present study explores the use of stable carbon isotopes to trace organic matter sources of intertidal nematodes in the Schelde estuary (SW Netherlands). Stable carbon isotope signatures of nematodes from a saltmarsh and 4 tidal flat stations were determined in spring and winter situations, and

  8. Comparison of aerobic denitrifying activity among three cultural species with various carbon sources.

    Science.gov (United States)

    Otani, Y; Hasegawa, K; Hanaki, K

    2004-01-01

    Abilities of three aerobic denitrifiers such as Alcaligenes faecalis, Microvirgula aerodenitrificans and Paracoccus pantotrophus were compared from the viewpoints of nitrate removal efficiency and organic matter utilization. First, the effect of carbon source was investigated. Although nitrate reduction was observed in all strains under aerobic conditions, a change of carbon source considerably affected the denitrification ability. In the case of P. pantotrophus, nitrate and nitrite were completely removed in three days under sodium acetate or leucine as a carbon source. In the case of A. faecalis, sufficient nitrate removal was observed only when sodium acetate or ethanol was added. P. pantotrophus and A. faecalis showed a higher ability of nitrate removal than that of M. aerodenitrificans. Therefore, P. pantotrophus was selected in order to investigate the effects of concentration and repetitive addition of carbon. Sodium acetate was used as a sole carbon source. Nitrate was not reduced when the carbon concentration was below 500 mgC/L. However, when carbon source was added repeatedly, nitrate was reduced under 100 mgC/L after the optical density of the bacterium reached above 1.0. This result indicated that a high enough level of bacterial density was necessary to express aerobic denitrification activity. PMID:15566182

  9. Using liquid waste streams as the moisture source during the hydrothermal carbonization of municipal solid wastes.

    Science.gov (United States)

    Li, Liang; Hale, McKenzie; Olsen, Petra; Berge, Nicole D

    2014-11-01

    Hydrothermal carbonization (HTC) is a thermal conversion process that can be an environmentally beneficial approach for the conversion of municipal solid wastes to value-added products. The influence of using activated sludge and landfill leachate as initial moisture sources during the carbonization of paper, food waste and yard waste over time at 250°C was evaluated. Results from batch experiments indicate that the use of activated sludge and landfill leachate are acceptable alternative supplemental liquid sources, ultimately imparting minimal impact on carbonization product characteristics and yields. Regression results indicate that the initial carbon content of the feedstock is more influential than any of the characteristics of the initial liquid source and is statistically significant when describing the relationship associated with all evaluated carbonization products. Initial liquid-phase characteristics are only statistically significant when describing the solids energy content and the mass of carbon in the gas-phase. The use of these alternative liquid sources has the potential to greatly increase the sustainability of the carbonization process. A life cycle assessment is required to quantify the benefits associated with using these alternative liquid sources. PMID:25074717

  10. Black carbon emissions from Russian diesel sources: case study of Murmansk

    OpenAIRE

    Evans, M.; N. Kholod; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2015-01-01

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road ...

  11. Black carbon emissions from Russian diesel sources: case study of Murmansk

    OpenAIRE

    Evans, M.; N. Kholod; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2015-01-01

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in the Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on...

  12. The investments in renewable energy sources: do low carbon economies better invest in green technologies?

    OpenAIRE

    Antonio Angelo Romano; Giuseppe Scandurra (eds.)

    2011-01-01

    The aim of this study is to analyse the driving of investment in renewable energy sources in low carbon and high carbon economies. To address these issues, a dynamic panel analysis of the renewable investment in a sample of 29 countries was proposed. Results demonstrate that the dynamic of investments in renewable sources is similar in the two panels, and depends by nuclear power generation, GDP and technological efficiency. Results show that countries try to reduce their environmental footpr...

  13. Effect of Different Carbon Source on Expression of Carotenogenic Genes and Astaxanthin Production in Xanthophyllomyces dendrorhous

    OpenAIRE

    Wei Wu; Xin Yu

    2013-01-01

    The present research gives an insight into astaxanthin production, as well as transcription differences of four key carotenogenic genes, in Xanthophyllomyces dendrorhous when cultured with various carbon sources and soybean oil as co-substrates. Glucose was found to be the carbon source with best culture growth and astaxanthin production and the addition of 2% (v/v) soybean oil resulted in even higher astaxanthin producing. In addition, four carotenogenic genes encoding geranylgeranyl diphosp...

  14. Effect of carbon source type on intracellular stored polymers during endogenous denitritation (ED) treating landfill leachate.

    Science.gov (United States)

    Miao, Lei; Wang, Shuying; Li, Baikun; Cao, Tianhao; Zhang, Fangzhai; Wang, Zhong; Peng, Yongzhen

    2016-09-01

    Glycogen accumulating organisms (GAOs) capable of storing organic compounds as polyhydroxyalkanoate (PHA) have been used for endogenous denitritation (ED), but the effect of carbon sources type on nitrogen removal performance of GAOs treating landfill leachate is unclear. In this study, a successful ED system treating landfill leachate (COD/NH4(+)-N (C/N): 4) without external carbon source addition was applied. The mature leachate with C/N of 1 was used as the feeding base solution, with acetate, propionate, and glucose examined as the carbon sources, and their effects on yields and compositions of PHA produced by GAOs were determined and associated with nitrogen removal performance. In the case of sole carbon source, acetate was much easier to be stored than propionate and glucose, which led to a higher nitrogen removal efficiency. Glucose had the lowest amount of PHA storage and led to the lowest performance. In the case of composite carbon sources (two scenarios: acetate + propionate; acetate + propionate + glucose), GAOs stored sufficient PHA and exhibited similar nitrogen removal efficiencies. Moreover, type of carbon source influenced the compositions of PHA. The polyhydroxybutyrate (PHB) fraction in PHA was far more than polyhydroxyvalerate (PHV) in all tests. PHV was synthesized only when acetate existed in carbon source. The microbial diversity analysis revealed that Proteobacteria was the most abundant phylum. Among the 108 genera detected in this ED system, the genera responsible for denitritation were Thauera, Paracoccus, Ottowia and Comamonadaceae_unclassified, accounting for 46.21% of total bacteria. Especially, Paracoccus and Comamonadaceae_unclassified transformed the carbon source into PHA for denitritation, and carried out endogenous denitritation. PMID:27232984

  15. Distribution of organic carbon and petroleum source rock potential of Cretaceous and lower Tertiary carbonates, South Florida Basin: preliminary results

    Science.gov (United States)

    Palacas, James George

    1978-01-01

    Analyses of 134 core samples from the South Florida Basin show that the carbonates of Comanchean age are relatively richer in average organic carbon (0.41 percent) than those of Coahuilan age (0.28 percent), Gulfian age (0.18 percent) and Paleocene age (0.20 percent). They are also nearly twice as rich as the average world, wide carbonate (average 0.24 percent). The majority of carbonates have organic carbons less than 0.30 percent but the presence of many relatively organic rich beds composed of highly bituminous, argillaceous, highly stylolitic, and algal-bearing limestones and dolomites accounts for the higher percentage of organic carbon in some of the stratigraphic units. Carbonate rocks that contain greater than 0.4 percent organic carbon and that might be considered as possible petroleum sources were noted in almost each subdivision of the Coahuilan and Comanchean Series but particularly the units of Fredericksburg 'B', Trinity 'A', Trinity 'F', and Upper Sunniland. Possible source rocks have been ascribed by others to the Lower Sunniland, but lack of sufficient samples precluded any firm assessment in this initial report. In the shallower section of the basin, organic-rich carbonates containing as much as 3.2 percent organic carbon were observed in the lowermost part of the Gulfian Series and carbonate rocks with oil staining or 'dead' and 'live oil' were noted by others in the uppermost Gulfian and upper Cedar Keys Formation. It is questionable whether these shallower rocks are of sufficient thermal maturity to have generated commercial oil. The South Florida basin is still sparsely drilled and produces only from the Sunniland Limestone at an average depth of 11,500 feet (3500 m). Because the Sunniland contains good reservoir rocks and apparently adequate source rocks, and because the success rate of new oil field discoveries has increased in recent years, the chances of finding additional oil reserves in the Sunniland are promising. Furthermore, the

  16. Simulation and Optimization of a Carbon Nanotube Electron Source

    Czech Academy of Sciences Publication Activity Database

    Knápek, Alexandr; Radlička, Tomáš; Krátký, Stanislav

    2015-01-01

    Roč. 21, S4 (2015), s. 60-65. ISSN 1431-9276 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : carbon nanotube * electron beam lithography Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.877, year: 2014

  17. Design and simulation of a carbon nanotube electron source

    Czech Academy of Sciences Publication Activity Database

    Knápek, Alexandr; Radlička, Tomáš; Krátký, Stanislav

    Brno: Institute of Scientific Instruments AS CR, v. v. i, 2014. s. 62. ISBN 978-80-87441-11-4. [International Conference on Charged Parrticle Optics /9./. 31.08.2014-05.09.2014, Brno] Institutional support: RVO:68081731 Keywords : field emission * carbon nanotube s * Monte-Carlo simulation s * finite element method Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  18. Conductivity of carbon materials for alternative energy sources

    Czech Academy of Sciences Publication Activity Database

    Tichý, J.; Novák, V.; Barath, Peter

    Brno : University of technology Brno, 2009, s. 192-194. ISBN 978-80-214-3943-6. [International Conference Advanced Batteries, Accumulators and Fuel Cells /10./. Brno (CZ), 30.08.2009-02.10.2009] Institutional research plan: CEZ:AV0Z40320502 Keywords : electrodes with carbon materials Subject RIV: CG - Electrochemistry

  19. Intertidal zones as carbon dioxide sources to coastal oceans

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.; George, M.D.; Rajagopal, M.D.

    To understand the factors controlling carbon dioxide (CO sub(2)) exchanges near land-sea boundary diurnal observations have been made twice on CO sub(2) in the air and water in a coastal region. The results suggest that CO sub(2) enrichment...

  20. Optimization of an Atmospheric Carbon Source for Extremophile Cyanobacteria

    Science.gov (United States)

    Beaubien, Courtney

    This thesis examines the use of the moisture swing resin materials employed at the Center for Negative Carbon Emissions (CNCE) in order to provide carbon dioxide from ambient air to photobioreactors containing extremophile cyanobacteria cultured at the Arizona Center for Algae Technology and Innovation (AzCATI). For this purpose, a carbon dioxide feeding device was designed, built, and tested. The results indicate how much resin should be used with a given volume of algae medium: approximately 500 grams of resin can feed 1% CO2 at about three liters per minute to a ten liter medium of the Galdieria sulphuraria 5587.1 strain for one hour (equivalent to about 0.1 grams of carbon dioxide per hour per seven grams of algae). Using the resin device, the algae grew within their normal growth range: 0.096 grams of ash-free dry weight per liter over a six hour period. Future applications in which the resin-to-algae process can be utilized are discussed.

  1. Beam test of compact ECR ion source for carbon therapy

    International Nuclear Information System (INIS)

    Ion source for medical facilities should have characteristics of easy maintenance, low electric power, good stability and long operation time without maintenance (one year or more). Based on the proto type compact source, a 10 GHz compact ECR ion source with all permanent magnets has been developed. Peaks of the mirror magnetic field along the beam axis are 0.59 T at the extraction side and 0.87 T at the gas injection side, respectively, while the minimum B strength is 0.25 T. The source has a diameter of 320 mm and a length of 295 mm. The result of beam tests shows that a C4+ intensity of 530 μA was obtained under an extraction voltage of 45 kV. This paper describes the design detail and the experimental results for the new source. (author)

  2. Ammonia-based intermittent aeration control optimized for efficient nitrogen removal.

    Science.gov (United States)

    Regmi, Pusker; Bunce, Ryder; Miller, Mark W; Park, Hongkeun; Chandran, Kartik; Wett, Bernhard; Murthy, Sudhir; Bott, Charles B

    2015-10-01

    This work describes the development of an intermittently aerated pilot-scale process (V = 0.45 m(3) ) operated for optimized efficient nitrogen removal in terms of volume, supplemental carbon and alkalinity requirements. The intermittent aeration pattern was controlled using a strategy based on effluent ammonia concentration set-points. The unique feature of the ammonia-based aeration control was that a fixed dissolved oxygen (DO) set-point was used and the length of the aerobic and anoxic time (anoxic time ≥25% of total cycle time) were changed based on the effluent ammonia concentration. Unlike continuously aerated ammonia-based aeration control strategies, this approach offered control over the aerobic solids retention time (SRT) to deal with fluctuating ammonia loading without solely relying on changes to the total SRT. This approach allowed the system to be operated at a total SRT with a small safety factor. The benefits of operating at an aggressive SRT were reduced hydraulic retention time (HRT) for nitrogen removal. As a result of such an operation, nitrite oxidizing bacteria (NOB) out-selection was also obtained (ammonia oxidizing bacteria [AOB] maximum activity: 400 ± 79 mgN/L/d, NOB maximum activity: 257 ± 133 mgN/L/d, P < 0.001) expanding opportunities for short-cut nitrogen removal. The pilot demonstrated a total inorganic nitrogen (TIN) removal rate of 95 ± 30 mgN/L/d at an influent chemical oxygen demand: ammonia (COD/NH4 (+) -N) ratio of 10.2 ± 2.2 at 25°C within the hydraulic retention time (HRT) of 4 h and within a total SRT of 5-10 days. The TIN removal efficiency up to 91% was observed during the study, while effluent TIN was 9.6 ± 4.4 mgN/L. Therefore, this pilot-scale study demonstrates that application of the proposed on-line aeration control is capable of relatively high nitrogen removal without supplemental carbon and alkalinity addition at a low HRT. PMID:26058705

  3. Development of a stationary carbon emission inventory for Shanghai using pollution source census data

    Science.gov (United States)

    Li, Xianzhe; Jiang, Ping; Zhang, Yan; Ma, Weichun

    2016-03-01

    This study utilizes 521,631 activity data points from the 2007 Shanghai Pollution Source Census to compile a stationary carbon emission inventory for Shanghai. The inventory generated from our dataset shows that a large portion of Shanghai's total energy use consists of coal-oriented energy consumption. The electricity and heat production industries, iron and steel mills, and the petroleum refining industry are the main carbon emitters. In addition, most of these industries are located in Baoshan District, which is Shanghai's largest contributor of carbon emissions. Policy makers can use the enterpriselevel carbon emission inventory and the method designed in this study to construct sound carbon emission reduction policies. The carbon trading scheme to be established in Shanghai based on the developed carbon inventory is also introduced in this paper with the aim of promoting the monitoring, reporting and verification of carbon trading. Moreover, we believe that it might be useful to consider the participation of industries, such as those for food processing, beverage, and tobacco, in Shanghai's carbon trading scheme. Based on the results contained herein, we recommend establishing a comprehensive carbon emission inventory by inputting data from the pollution source census used in this study.

  4. Using hydrocarbon as a carbon source for synthesis of carbon nanotube by electric field induced needle-pulsed plasma

    International Nuclear Information System (INIS)

    In this work different hydrocarbons are used as the carbon source, in the production of carbon nanotubes (CNTs) and nano onions. An electric field induced needle pulse arc-discharge reactor is used. The influence of starting carbon on the synthesis of CNTs is investigated. The production efficiency is compared for Acetone, Isopropanol and Naphthalene as simple hydrocarbons. The hydrocarbons are preheated and then pretreated by electric field before being exposed to plasma. The hydrocarbon vapor is injected into plasma through a graphite spout in the cathode assembly. The pulsed plasma takes place between two graphite rods while a strong electric field has been already established alongside the electrodes. The pulse width is 0.3 μs. Mechanism of precursor decomposition is discussed by describing three forms of energy that are utilized to disintegrate the precursor molecules: thermal energy, electric field and kinetic energy of plasma. Molecular polarity of a hydrocarbon is one of the reasons for choosing carbon raw material as a precursor in an electric field induced low power pulsed-plasma. The results show that in order to obtain high quality carbon nanotubes, Acetone is preferred to Isopropanol and Naphthalene. Scanning probe microscopy techniques are used to investigate the products. - Highlights: • We synthesized CNTs (carbon nano tubes) by needle pulsed plasma. • We use different hydrocarbons as carbon source in the production of CNTs. • We investigated the influence of starting carbon on the synthesis of CNTs. • Thermal energy, electric field and kinetic energy are used to break carbon bonds. • Polar hydrocarbon molecules are more efficient than nonpolar ones in production

  5. Changing sources and sinks of carbon in boreal ecosystems of Interior Alaska: Current and future perspectives

    Science.gov (United States)

    Douglas, T. A.; Jones, M.; Hiemstra, C. A.

    2012-12-01

    Future climate scenarios predict a roughly 5°C increase in mean annual air temperatures for the Alaskan Interior over the next 80 years. Increasing temperatures and greater frequency and severity of climate-induced disturbances such as wildfires will be enough to initiate permafrost degradation in many areas of Alaska, leading to major changes in surface hydrology and ecosystem structure and function. This, in turn, is expected to alter the current inventories of carbon sources and sinks in the region and provide a management challenge for carbon itemization efforts. To assist land managers in adapting and planning for potential changes in Interior Alaska carbon cycling we synthesize information on climate, ecosystem processes, vegetation, and soil, permafrost, and hydrologic regimes in Interior Alaska. Our goal is to provide an assessment of the current and likely future regime of Interior Alaska carbon sources and sinks. For our carbon assessment we: 1) synthesize the most recent results from numerous studies on the carbon cycle with a focus on research from the Alaskan boreal biome, 2) assemble a summary of estimates of carbon sources in soil and vegetation in Interior Alaska, 3) categorize carbon sources and sinks for predominant Interior Alaska ecosystems, and 4) identify expected changes in sources and sinks with climate change and human activities. This information is used to provide recommendations on potential actions land managers can take to minimize carbon export from the boreal forest. Though the results from our project are geared primarily toward policy makers and land managers we also provide recommendations for filling research gaps that currently present uncertainty in our understanding of the carbon cycle in boreal forest ecosystems of Interior Alaska.

  6. Dynamic balancing of isoprene carbon sources reflects photosynthetic and photorespiratory responses to temperature stress.

    Science.gov (United States)

    Jardine, Kolby; Chambers, Jeffrey; Alves, Eliane G; Teixeira, Andrea; Garcia, Sabrina; Holm, Jennifer; Higuchi, Niro; Manzi, Antonio; Abrell, Leif; Fuentes, Jose D; Nielsen, Lars K; Torn, Margaret S; Vickers, Claudia E

    2014-12-01

    The volatile gas isoprene is emitted in teragrams per annum quantities from the terrestrial biosphere and exerts a large effect on atmospheric chemistry. Isoprene is made primarily from recently fixed photosynthate; however, alternate carbon sources play an important role, particularly when photosynthate is limiting. We examined the relative contribution of these alternate carbon sources under changes in light and temperature, the two environmental conditions that have the strongest influence over isoprene emission. Using a novel real-time analytical approach that allowed us to examine dynamic changes in carbon sources, we observed that relative contributions do not change as a function of light intensity. We found that the classical uncoupling of isoprene emission from net photosynthesis at elevated leaf temperatures is associated with an increased contribution of alternate carbon. We also observed a rapid compensatory response where alternate carbon sources compensated for transient decreases in recently fixed carbon during thermal ramping, thereby maintaining overall increases in isoprene production rates at high temperatures. Photorespiration is known to contribute to the decline in net photosynthesis at high leaf temperatures. A reduction in the temperature at which the contribution of alternate carbon sources increased was observed under photorespiratory conditions, while photosynthetic conditions increased this temperature. Feeding [2-(13)C]glycine (a photorespiratory intermediate) stimulated emissions of [(13)C1-5]isoprene and (13)CO2, supporting the possibility that photorespiration can provide an alternate source of carbon for isoprene synthesis. Our observations have important implications for establishing improved mechanistic predictions of isoprene emissions and primary carbon metabolism, particularly under the predicted increases in future global temperatures. PMID:25318937

  7. Development of compact ECR ion source for carbon therapy facility

    International Nuclear Information System (INIS)

    A 10 GHz compact Electron Cyclotron Resonance (ECR) ion source with all permanent magnets has been developed. Peaks of the mirror magnetic field along the beam axis are 0.59 T at the extraction side and 0.87 T at the gas injection side, respectively, while the minimum B strength is 0.25 T. The source has a diameter of 320 mm and a length of 295 mm. The result of beam tests shows that a C4+ intensity of 500 μA was obtained under an extraction voltage of 30 kV. This paper describes the design detail and the experimental results for the new source. (author)

  8. Study on the threshold value of organic enrichment of carbonate as gas source rocks

    Institute of Scientific and Technical Information of China (English)

    XUE Haitao; LU Shuangfang; ZHONG Ningning; WANG Bo

    2004-01-01

    In this paper, calculations have been performed about gas quantity of generation, adsorption, dissolving in oil, dissolving in water, diffusion of unit area carbonate rocks at different geologic conditions in the Tarim basin. According to the material balance principle, the corresponding organic carbon content when gas started expelling from source rocks with separate phases has been worked out. We regard it as the theoretical threshold value (TOCmin) of gas source rocks under the same geologic condition. Based on the simulating calculation, a fact has been discovered that TOCmin decreases with the increasing source rocks thickness, decreases at the beginning and then increases with the increasing maturity and decreases with the better type of organic matter. TOCmin evaluation table of carbonate gas source rocks in the Tarim basin has been established. Investigations indicate that the TOCmin of carbonate gas source rocks varies greatly with the differences of geologic conditions, and gas source rocks cannot be evaluated with a unified TOC threshold value. And we also establish a preliminary evaluation table of TOC industrial threshold value, TOCgy, of carbonate gas source rocks in the Tarim basin.

  9. Oxidation of magnetite in aerated aqueous media

    International Nuclear Information System (INIS)

    Metastable equilibria involving phases less stable than hematite can be significantly more oxidizing than the calculated equilibrium between well-crystallized hematite and magnetite. In this report, generalized solubility and stability relationships between magnetite and Fe2O3.xH2O phases are derived to describe the metastable equilibria. Experiments with synthetic magnetite powders in aerated aqueous solutions show that crystalline hematite is formed within days at temperatures above 100 C in pure water or solutions containing anions (e.g., Cl-, SO42-, HCO3-) that do not form very strong surface complexes with iron oxides. In the presence of dissolved phosphate or silica, however, the dissolution-precipitation route to hematite is strongly inhibited, and maghemite is a persistent metastable product. Thus, phosphate or silica are expected to delay the approach to magnetite-hematite equilibrium in aerated groundwaters conditioned by magnetite. These findings are presented in the context of nuclear fuel waste disposal. (author). 63 refs., 1 tab., 11 figs

  10. Estimating the seasonal carbon source-sink geography of a natural, steady-state terrestrial biosphere

    Science.gov (United States)

    Box, Elgene O.

    1988-01-01

    The estimation of the seasonal dynamics of biospheric-carbon sources and sinks to be used as an input to global atmospheric CO2 studies and models is discussed. An ecological biosphere model is given and the advantages of the model are examined. Monthly maps of estimated biospheric carbon source and sink regions and estimates of total carbon fluxes are presented for an equilibrium terrestrial biosphere. The results are compared with those from other models. It is suggested that, despite maximum variations of atmospheric CO2 in boreal latitudes, the enormous contributions of tropical wet-dry regions to global atmospheric CO2 seasonality can not be ignored.

  11. HYDRODYNAMICS INfluence on oxidative capacity of AERATION BASIN

    OpenAIRE

    Kulkov Viktor Nikolaevich; Solopanov Evgenij Jurjevich

    2012-01-01

    The velocity fields of water flow to the impact on the hydrodynamic conditions in the aeration basin by the guide plate. It is shown that one can optimize the hydrodynamics of the aeration basin in order to increase its oxidative capacity.

  12. Composting paper mill deinking sludge with forced aeration

    Energy Technology Data Exchange (ETDEWEB)

    Brouillette, M.; Trepanier, L.; Gallichand, J.; Beauchamp, C. [Laval Univ., Quebec City, PQ (Canada)

    1996-04-01

    A composting strategy to dispose of deinking sludge was discussed. Deinking sludge is a waste by-product containing mainly paper fibres, clay particles and ink. Composting with forced aeration can reduce the volume and stabilize the sludge so it may be economically used in agricultural, landscaping and horticultural applications. In this study, static pile forced aeration was used as an alternative to mechanical pile turning. Two piles of 2 to 3 metres in height were used with three aeration pipes of different aeration levels. Results showed that 3 metre piles required longer aeration times to maintain temperatures in the required range of 50-65 degrees C. Water content remained within 60-71% for optimum composting. Fibre levels decreased gradually during the experiment, with cellulose being the most degraded. Aeration improved micro organic activity; organic nitrogen was also higher in aerated treatments. It was concluded that composting of deinking sludge with forced aeration is feasible in northeastern Canada even with outside temperatures as low as -20 degrees C. 20 refs., 4 tabs., 8 figs.

  13. OXIDATION OF AS(III) BY AERATION AND STORAGE

    Science.gov (United States)

    A study of the effects of aeration and storage on the oxidation of arsenic(III) was undertaken at three utilities in the US to establish the engineering significance of aeration as a potential pre-treatment method for arsenic removal. The results of this study clearly establish t...

  14. Carbon sources of natural cyanamide in Vicia villosa subsp. varia.

    Science.gov (United States)

    Kamo, Tsunashi; Kasahara, Ryohei; Abe, Shun; Hirota, Mitsuru; Sugano, Mami; Yamaya, Hiroko; Hiradate, Syuntaro; Fujii, Yoshiharu

    2010-10-01

    The ¹³C labels of [¹³C]carbon dioxide and D-[¹³C₆]glucose were incorporated into cyanamide (NH₂CN) when they were administered to Vicia villosa subsp. varia shoots. In contrast, the administration of sodium [2,3-¹³C₂]pyruvate did not affect the relative area of the [M + 1]+ ion of cyanamide in the gas chromatography-mass spectrometry analysis. [2,3-¹³C₂]pyruvate was incorporated into organic acids that are part of the citric acid cycle, such as succinate and fumarate, confirming that the shoots absorbed and metabolised it. These observations demonstrated that the carbon atom of cyanamide is derived from any of the carbohydrates that are present upstream of pyruvate in the metabolic pathway. PMID:20954091

  15. Metabolism of various carbon sources by Azospirillum brasilense.

    OpenAIRE

    Westby, C A; Cutshall, D S; Vigil, G V

    1983-01-01

    Azospirillum brasilense Sp7 and two mutants were examined for 19 carbon metabolism enzymes. The results indicate that this nitrogen fixer uses the Entner-Doudoroff pathway for gluconate dissimilation, lacks a catabolic but has an anabolic Embden-Meyerhof-Parnas hexosephosphate pathway, has amphibolic triosephosphate enzymes, lacks a hexose monophosphate shunt, and has lactate dehydrogenase, malate dehydrogenase, and glycerokinase. The mutants are severely deficient in phosphoglycerate and pyr...

  16. Stable carbon isotope analysis of nucleic acids to trace sources of dissolved substrates used by estuarine bacteria.

    OpenAIRE

    Coffin, R B; Velinsky, D J; R. Devereux; Price, W A; Cifuentes, L A

    1990-01-01

    The natural abundance of stable carbon isotopes measured in bacterial nucleic acids extracted from estuarine bacterial concentrates was used to trace sources of organic matter for bacteria in aquatic environments. The stable carbon isotope ratios of Pseudomonas aeruginosa and nucleic acids extracted from cultures resembled those of the carbon source on which bacteria were grown. The carbon isotope discrimination between the substrate and total cell carbon from bacterial cultures averaged 2.3%...

  17. EFFECT OF AERATOR ON HYDRAULIC DRAG ACTING ON A CHUTE

    Institute of Scientific and Technical Information of China (English)

    NI Han-gen; LI Xin; ZHOU Jing; JIN Qiao

    2005-01-01

    The formulae used to calculate the friction in the non-uniform flow chute were examined with the experimental data, and the results show that the accuracy of the formula is enough for engineering applications. A comparison between the results of friction respectively from the uniform flow assumption and the non-uniform flow approximation indicates that the former is an order of magnitude larger than the latter in the case of steep chute. The hydraulic drag on a steep chute with aerators was measured on the hydraulic model directly and the coefficient of the aerator effect on the drag was obtained. The variation patterns of the wall shear just downstream of the aerators were investigated and the mechanism of the increase in the drag by aerator were analyzed qualitatively with the measured water-depths just downstream the aerators.

  18. Two-phase flow simulation of aeration on stepped spillway

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiangju; LUO Lin; ZHAO Wenqian; LI Ran

    2004-01-01

    Stepped spillways have existed as escape works for a very long time. It is found that water can trap a lot of air when passing through steps and then increasing oxygen content in water body, so stepped spillways can be used as a measure of re-aeration and to improve water quality of water body. However, there is no reliable theoretical method on quantitative calculation of re-aeration ability for the stepped spillways. By introducing an air-water two-phase flow model, this paper used k-ε turbulence model to calculate the characteristic variables of free-surface aeration on stepped spillway. The calculated results fit with the experimental results well. It supports that the numerical modeling method is reasonable and offers firm foundation on calculating re-aeration ability of stepped spillways. The simulation approach can provide a possible optimization tool for designing stepped spillways of more efficient aeration capability.

  19. A novel approach to control atmospheric methane emissions from low-volume point sources and diffused area sources

    Energy Technology Data Exchange (ETDEWEB)

    Hettiaratchi, J.P.A.; Pokhrel, D.; Chandrakanthi, M. [Calgary Univ., AB (Canada)

    2003-07-01

    Over the past one hundred years, the atmospheric concentration of methane has significantly increased. The search for inexpensive techniques for reducing anthropogenic methane gas emissions into the atmosphere have led the authors to propose a technique called methanobiofiltration (MBF), which utilizes a naturally occurring bacterium to convert methane into carbon dioxide. It was shown that this method can be applied where conventional methods to extract methane for energy recovery may not be viable, such as controlling methane emissions from low volume, but numerous, or spatially diffused sources. A long-term research program, which involved laboratory based experimental studies, pilot-scale field studies and mathematical modeling was carried out. Several filter media were tested using passively aerated biofilter columns. The highest oxidation rate was obtained with compost. A decrease in the rate of oxidation was noted after reaching a maximum value within 100 days of continuous operation. Passively aerated biofilter columns did not perform as well as actively aerated columns. The authors presented the preliminary results obtained from two passively aerated pilot-scale field MBFs. The MBF design curves were developed using a series of 480 model simulations performed under a one-dimensional reactive transport model. 5 refs., 10 figs.

  20. A shift of thermokarst lakes from carbon sources to sinks during the Holocene epoch

    Science.gov (United States)

    Walter Anthony, K. M.; Zimov, S. A.; Grosse, G.; Jones, Miriam C.; Anthony, P.; Chapin, F. S., III; Finlay, J. C.; Mack, M. C.; Davydov, S.; Frenzel, P.F.; Frolking, S.

    2014-01-01

    Thermokarst lakes formed across vast regions of Siberia and Alaska during the last deglaciation and are thought to be a net source of atmospheric methane and carbon dioxide during the Holocene epoch1,2,3,4. However, the same thermokarst lakes can also sequester carbon5, and it remains uncertain whether carbon uptake by thermokarst lakes can offset their greenhouse gas emissions. Here we use field observations of Siberian permafrost exposures, radiocarbon dating and spatial analyses to quantify Holocene carbon stocks and fluxes in lake sediments overlying thawed Pleistocene-aged permafrost. We find that carbon accumulation in deep thermokarst-lake sediments since the last deglaciation is about 1.6 times larger than the mass of Pleistocene-aged permafrost carbon released as greenhouse gases when the lakes first formed. Although methane and carbon dioxide emissions following thaw lead to immediate radiative warming, carbon uptake in peat-rich sediments occurs over millennial timescales. We assess thermokarst-lake carbon feedbacks to climate with an atmospheric perturbation model and find that thermokarst basins switched from a net radiative warming to a net cooling climate effect about 5,000 years ago. High rates of Holocene carbon accumulation in 20 lake sediments (47±10 grams of carbon per square metre per year; mean±standard error) were driven by thermokarst erosion and deposition of terrestrial organic matter, by nutrient release from thawing permafrost that stimulated lake productivity and by slow decomposition in cold, anoxic lake bottoms. When lakes eventually drained, permafrost formation rapidly sequestered sediment carbon. Our estimate of about 160petagrams of Holocene organic carbon in deep lake basins of Siberia and Alaska increases the circumpolar peat carbon pool estimate for permafrost regions by over 50 per cent (ref. 6). The carbon in perennially frozen drained lake sediments may become vulnerable to mineralization as permafrost disappears7

  1. Compact ECR ion source with permanent magnets for carbon therapy

    International Nuclear Information System (INIS)

    Ion sources for the medical facilities should have the following characteristics of easy maintenance, low electric power, good stability, and long operation time without trouble (1 year or longer). For this, a 10 GHz compact electron cyclotron resonance ion source (ECRIS) with all permanent magnets was developed. The beam intensity and stability for C4+ were 280 e μA and better than 6% during 20 h with no adjustment of any source parameters. These results were acceptable for the medical requirements. Recently, many plans were proposed to construct the next generation cancer treatment facility. For such a facility we have designed an all permanent magnet ECRIS, in which a high magnetic field is chosen for increasing the beam intensity. The maximum mirror magnetic fields on the beam axis are 0.59 T at the extraction side and 0.87 T at the gas injection side, while the minimum B strength is 0.25 T. The source has a diameter of 32 cm and a length of 29.5 cm. Details of the design of this source and its background are described in this article

  2. Electron string ion sources for carbon ion cancer therapy accelerators

    CERN Document Server

    Boytsov, A Yu; Donets, E D; Donets, E E; Katagiri, K; Noda, K; Ponkin, D O; Ramzdorf, A Yu; Salnikov, V V; Shutov, V B

    2015-01-01

    The Electron String type of Ion Sources (ESIS) was developed, constructed and tested first in the Joint Institute for Nuclear Research. These ion sources can be the appropriate sources for production of pulsed C4+ and C6+ ion beams which can be used for cancer therapy accelerators. In fact the test ESIS Krion-6T already now at the solenoid magnetic field only 4.6 T provides more than 10^10 C4+ ions per pulse and about 5*10^9 C6+ ions per pulse. Such ion sources could be suitable for application at synchrotrons. It was also found, that Krion-6T can provide more than 10^11 C6+ ions per second at 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. As for production of 11C radioactive ion beams ESIS can be the most economic kind of ion source. To proof that the special cryogenic cell for pulse injection of gaseous species into electron string was successfully tested using the ESIS Krion-2M.

  3. Carbon source/sink function of a subtropical, eutrophic lake determined from an overall mass balance and a gas exchange and carbon burial balance

    International Nuclear Information System (INIS)

    Although studies on carbon burial in lake sediments have shown that lakes are disproportionately important carbon sinks, many studies on gaseous carbon exchange across the water-air interface have demonstrated that lakes are supersaturated with CO2 and CH4 causing a net release of CO2 and CH4 to the atmosphere. In order to more accurately estimate the net carbon source/sink function of lake ecosystems, a more comprehensive carbon budget is needed, especially for gaseous carbon exchange across the water-air interface. Using two methods, overall mass balance and gas exchange and carbon burial balance, we assessed the carbon source/sink function of Lake Donghu, a subtropical, eutrophic lake, from April 2003 to March 2004. With the overall mass balance calculations, total carbon input was 14 905 t, total carbon output was 4950 t, and net carbon budget was +9955 t, suggesting that Lake Donghu was a great carbon sink. For the gas exchange and carbon burial balance, gaseous carbon (CO2 and CH4) emission across the water-air interface totaled 752 t while carbon burial in the lake sediment was 9477 t. The ratio of carbon emission into the atmosphere to carbon burial into the sediment was only 0.08. This low ratio indicates that Lake Donghu is a great carbon sink. Results showed good agreement between the two methods with both showing Lake Donghu to be a great carbon sink. This results from the high primary production of Lake Donghu, substantive allochthonous carbon inputs and intensive anthropogenic activity. Gaseous carbon emission accounted for about 15% of the total carbon output, indicating that the total output would be underestimated without including gaseous carbon exchange. - Due to high primary production, substantive allochthonous carbon inputs and intensive anthropogenic acitivity, subtropical, eutrophic Lake Donghu is a great carbon sink

  4. Immunotoxic potential of aeration lagoon effluents for the treatment of domestic and hospital wastewaters in the freshwater mussel Elliptio complanata.

    Science.gov (United States)

    Gagné, Francois; André, Chantale; Fortier, Marlène; Fournier, Michel

    2012-01-01

    Municipal wastewaters are major sources of pollution for the aquatic biota. The purpose of this study was to determine the levels of some pharmaceutical products and the immunotoxic potential of a municipal wastewater aeration lagoon for the treatment of the domestic wastewaters of a small town with wastewater inputs from a 400-bed hospital complex. Endemic mussels were collected, caged and placed in the final aeration lagoon and at sites 1 km upstream and 1 km downstream of the effluent outfall in the receiving river for a period of 14 days. The results showed that the final aeration lagoon contained high levels of total coliforms, conductivity and low dissolved oxygen (2.9 mg/L) as well as detectable amounts of trimethoprim, carbamazepine, gemfibrozil, and norfloxacin at concentrations exceeding 50 ng/L. The lagoon effluent was indeed toxic to the mussel specimens, as evidenced by the appearance of mortality after 14 days (10% mortality), decreased mussel weight-to-shell-length ratio and loss of hemocyte viability. The number of adhering hemocytes, phagocytic activity, total nitrite levels and arachidonic cyclooxygenase activity were significantly higher in mussels placed in the final aeration lagoon. A multivariate analysis also revealed that water pH, conductivity, total coliforms and dissolved oxygen were the endpoints most closely linked with phagocytic activity, the amount of adhering hemocytes and loss of hemocyte viability. In conclusion, exposure of mussels to treated aerated lagoon wastewater is deleterious to freshwater mussels where the immune system is compromised. PMID:22893952

  5. A one-step single source route to carbon nanotubes

    Indian Academy of Sciences (India)

    Tao Cheng; Zhiyong Fang; Guifu Zou; Qixiu Hu; Biao Hu; Xiaozhi Yang; Youjin Zhang

    2006-12-01

    Carbon nanotubes (CNTs) have been synthesized via directly pyrolyzing ferrocene in the autoclave. The nanotubes with several micrometers in length have outer and inner diameters in the range of 40–100 nm and 20–40 nm, respectively. An yield of ∼70% of CNTs can be obtained without any accessorial solvents and catalysts. Experimental results showed that a temperature higher than 600°C in conjunction with proper pressure was favourable for achievement of the nanotubes. The growth mechanism of CNTs was also discussed.

  6. A series of tufted carbon fiber cathodes designed for different high power microwave sources

    Science.gov (United States)

    Liu, Lie; Li, Limin; Zhang, Jun; Zhang, Xiaoping; Wen, Jianchun; Liu, Yonggui

    2008-06-01

    We report the fabrication technique of tufted carbon fiber cathodes for different microwave sources. Three carbon fiber cathodes were constructed, including a planar cathode, an annular cathode, and a cylindrical cathode for radial emission. Experimental investigations on these cathodes were performed in a reflex triode virtual cathode oscillator (vircator), a backward wave oscillator (BWO), and a magnetically insulated transmission line oscillator (MILO), respectively. The pulse duration of microwave emission from the reflex triode vircator was lengthened by using the planar carbon fiber cathode. In the BWO with the annular carbon fiber cathode, the uniform electron beam with a kA /cm2 current density was observed. In addition, carbon fiber has great promise as field emitter for MILOs. These results show that the carbon fiber cathodes can be utilized for electron emission in high power diodes with different structures.

  7. Estimation of protective ability of soil-ground of aeration zone within the boundaries of the Chernobyl' NPP radiogeochemical effect

    International Nuclear Information System (INIS)

    The technique for numerical estimation of the soil-ground protective ability in the aeration zone for the Chernobyl' NPP region, which is determined by sorption because of wide ground water use as the main source of auxiliary and drinking water supply is described. Histograms for Cs-137 and Sr-90 distribution in soil-grounds, coefficients of Cs-137 and Sr-90 distribution in sandy-loamy grounds, are the effects of ground type in aeration zone on Cs-137 and Sr-90 absorption are estimated. The calculation scheme for soil-ground, and ground water protective abilities against long-living radionuclide effects is given. 10 refs.; 3 figs.; 1 tab

  8. A carbon nanotube field emission multipixel x-ray array source for microradiotherapy application

    OpenAIRE

    Wang, Sigen; Calderon, Xiomara; Peng, Rui; Schreiber, Eric C.; Zhou, Otto; Chang, Sha

    2011-01-01

    The authors report a carbon nanotube (CNT) field emission multipixel x-ray array source for microradiotherapy for cancer research. The developed multipixel x-ray array source has 50 individually controllable pixels and it has several distinct advantages over other irradiation source including high-temporal resolution (millisecond level), the ability to electronically shape the form, and intensity distribution of the radiation fields. The x-ray array was generated by a CNT cathode array (5×10)...

  9. Source and age of carbon in peatland surface waters: new insights from 14C analysis

    Science.gov (United States)

    Billett, Michael; Garnett, Mark; Dinsmore, Kerry; Leith, Fraser

    2013-04-01

    Peatlands are a significant source of carbon to the aquatic environment which is increasingly being recognised as an important flux pathway (both lateral and vertical) in total landscape carbon budgets. Determining the source and age of the carbon (in its various forms) is a key step to understanding the stability of peatland systems as well as the connectivity between the soil carbon pool and the freshwater environment. Novel analytical and sampling methods using molecular sieves have been developed for (1) within-stream, in situ sampling of CO2 in the field and (2) for the removal/separation of CO2 in the laboratory prior to 14C analysis of CH4. Here we present dual isotope (δ13C and 14C) data from freshwater systems in UK and Finnish peatlands to show that significant differences exist in the source and age of CO2, DOC (dissolved organic carbon) and POC (particulate organic carbon). Individual peatlands clearly differ in terms of their isotopic freshwater signature, suggesting that carbon cycling may be "tighter" in some systems compared to others. We have also measured the isotopic signature of different C species in peatland pipes, which appear to be able to tap carbon from different peat depths. This suggests that carbon cycling and transport within "piped-peatlands" may be more complex than previously thought. Some of our most recent work has focussed on the development of a method to measure the 14C component of CH4 in freshwaters. Initial results suggest that CH4 in peatland streams is significantly older than CO2 and derived from a much deeper source. We have also shown that the age (but not the source) of dissolved CO2 changes over the hydrological year in response to seasonal changes in discharge and temperature. Radiocarbon measurements in the peat-riparian-stream system suggest that a significant degree of connectivity exists in terms of C transport and cycling, although the degree of connectivity differs for individual C species. In summary, 14C

  10. The potential of non-carbon energy sources in developing countries - The case of the PRC

    International Nuclear Information System (INIS)

    While developing countries presently account for a small share of the world's carbon emissions, in coming years, the quantity of energy-related CO2 generated by developing nations will surpass the amount produced by industrialized countries. In response to this trend, an increasing amount o attention has been paid to the prospect of reducing emissions in developing countries by exploiting non-carbon energy resources. To date, however, financial constraints have limited the development of non-carbon alternatives; the costs of these sources typically loom far above the costs of conventional forms of energy. Due to its heavy reliance on coal energy, China makes a disproportionately high contribution to global CO2. In 1990, China's energy-related activities consumed 8% of the world's commercial energy, but accounted for 11% of global carbon emissions. While financial constraints will continue to hinder the exploration of non-carbon alternatives, increasing the roles of hydropower, nuclear energy, solar radiation and wind energy could play a major role in curtailing the growth of carbon emissions in the PRC. This paper evaluates the potential for integrating various non-carbon energy sources in China and provides possible strategies for deploying these sources

  11. Evaluation criteria for gas source rocks of marine carbonate in China

    Institute of Scientific and Technical Information of China (English)

    WANG Zhaoyun; ZHAO Wenzhi; WANG Yunpeng

    2005-01-01

    Hydrocarbon generating and expulsion simulation experiments are carried out using samples artifically matched between the acid-dissolved residue of relatively low-maturity limestone and the original sample. This work makes up for the insufficiency of source rock samples with high abundance of organic matters and low maturity in China. The organic carbon content of the 10 prepared samples varies between 0.15 % and 0.74 %. Pyrolysis data and simulation experiment results of hydrocarbon generating and expulsion, which were obtained by a high-temperature and high-pressure open system, indicate that the lower limit of organic carbon content for marine carbonate rock to generate and expel hydrocarbons is 0.23 %-0.31%. In combination with the numerical analysis of organic carbon in marine carbonate rocks from Tarim Basin, Sichuan Basin, Ordos Basin and North China, as well as the contribution of these gas source rocks to the discovered gas pools, we think that the organic carbon criterion for carbonate gas source rocks should be 0.3%.

  12. Organic carbon source and burial during the past one hundred years in Jiaozhou Bay, North China

    Institute of Scientific and Technical Information of China (English)

    LI Xuegang; YUAN Huamao; LI Ning; SONG Jinming

    2008-01-01

    Organic carbon (OC), total nitrogen (TN), and 210Pb in core sediment were measured to quantify the burial of organic carbon and the relative importance of allochthonous and autochthonous contributions during the past one hundred years in Jiaozhou Bay, North China. The core sediment was dated using 210Pb chronology, which is the most promising method for estimation of sedimentation rate on a time scale of 100-150 years. The variation of the burial flux of organic carbon in the past one hundred years can be divided into the following three stages: (1) relatively steady before 1980s; (2) increasing rapidly from the 1980s to a peak in the 1990s, and (3) decreasing from the 1990s to the present. The change is consistent with the amount of solid waste and sewage emptied into the bay. The OC:TN ratio was used to evaluate the source of organic carbon in the Jiaozhou Bay sediment. In the inner bay and bay mouth, the organic carbon was the main contributor from terrestrial sources, whereas only about half of organic carbon was contributed from terrestrial source in the outer bay. In the inner bay, the terrestrial source of organic carbon showed a steady change with an increase in the range of 69%-77% before 1990 to 93% in 2000, and then decreased from 2000 because of the decrease in the terrestrial input. In the bay mouth, the percentage of organic carbon from land reached the highest value with 94% in 1994. In the outer bay, the sediment source maintained steady for the past one hundred years.

  13. Carbon Dioxide Direct Cycle Modular Reactors for Decentralized Energy Sources

    International Nuclear Information System (INIS)

    Carbon dioxide is achievable higher cycle efficiency than helium in a direct gas turbine cycle system due to the real gas effect or inter molecular attraction force in the compression process especially in the vicinity of the critical points. Analyzing the cycle thermal performance of full, partial and non condensation cycles, the cycle efficiency is highest in the partial condensation cycle. A fast reactor employing the partial condensation cycle is expected to be a potential alternative option to LMFRs, allowing higher cycle efficiency than LMFRs at the same core outlet temperature, and excluding the problems related to safety, cost and maintenance. A thermal reactor employing the partial condensation cycle provides higher cycle efficiency (48%) at the moderate core outlet temperature of 650? than that of PBMR (46%) operated at 900? (author)

  14. Electron string ion sources for carbon ion cancer therapy accelerators

    Science.gov (United States)

    Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Katagiri, K.; Noda, K.; Ponkin, D. O.; Ramzdorf, A. Yu.; Salnikov, V. V.; Shutov, V. B.

    2015-08-01

    The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C4+ and C6+ ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 1010 C4+ ions per pulse and about 5 × 109 C6+ ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 1011 C6+ ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the 11C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C4+ ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of 11C, transporting to the tumor with the primary accelerated 11C4+ beam, this efficiency is preliminarily considered to be large enough to produce the 11C4+ beam from radioactive methane and to inject this beam into synchrotrons.

  15. Mineral Carbonation Potential of CO2 from Natural and Industrial-based Alkalinity Sources

    Science.gov (United States)

    Wilcox, J.; Kirchofer, A.

    2014-12-01

    Mineral carbonation is a Carbon Capture and Storage (CSS) technology where gaseous CO2 is reacted with alkaline materials (such as silicate minerals and alkaline industrial wastes) and converted into stable and environmentally benign carbonate minerals (Metz et al., 2005). Here, we present a holistic, transparent life cycle assessment model of aqueous mineral carbonation built using a hybrid process model and economic input-output life cycle assessment approach. We compared the energy efficiency and the net CO2 storage potential of various mineral carbonation processes based on different feedstock material and process schemes on a consistent basis by determining the energy and material balance of each implementation (Kirchofer et al., 2011). In particular, we evaluated the net CO2 storage potential of aqueous mineral carbonation for serpentine, olivine, cement kiln dust, fly ash, and steel slag across a range of reaction conditions and process parameters. A preliminary systematic investigation of the tradeoffs inherent in mineral carbonation processes was conducted and guidelines for the optimization of the life-cycle energy efficiency are provided. The life-cycle assessment of aqueous mineral carbonation suggests that a variety of alkalinity sources and process configurations are capable of net CO2 reductions. The maximum carbonation efficiency, defined as mass percent of CO2 mitigated per CO2 input, was 83% for CKD at ambient temperature and pressure conditions. In order of decreasing efficiency, the maximum carbonation efficiencies for the other alkalinity sources investigated were: olivine, 66%; SS, 64%; FA, 36%; and serpentine, 13%. For natural alkalinity sources, availability is estimated based on U.S. production rates of a) lime (18 Mt/yr) or b) sand and gravel (760 Mt/yr) (USGS, 2011). The low estimate assumes the maximum sequestration efficiency of the alkalinity source obtained in the current work and the high estimate assumes a sequestration efficiency

  16. Greenhouse gas production and efficiency of planted and artificially aerated constructed wetlands

    International Nuclear Information System (INIS)

    Greenhouse gas (GHG) emissions by constructed wetlands (CWs) could mitigate the environmental benefits of nutrient removal in these man-made ecosystems. We studied the effect of 3 different macrophyte species and artificial aeration on the rates of nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) production in CW mesocosms over three seasons. CW emitted 2-10 times more GHG than natural wetlands. Overall, CH4 was the most important GHG emitted in unplanted treatments. Oxygen availability through artificial aeration reduced CH4 fluxes. Plant presence also decreased CH4 fluxes but favoured CO2 production. Nitrous oxide had a minor contribution to global warming potential (GWP < 15%). The introduction of oxygen through artificial aeration combined with plant presence, particularly Typha angustifolia, had the overall best performance among the treatments tested in this study, including lowest GWP, greatest nutrient removal, and best hydraulic properties. - Methane is the main greenhouse gas produced in constructed wetlands and oxygen availability is the main factor controlling fluxes

  17. Removal of nitrogen from MBT residues by leachate recirculation in combination with intermittent aeration.

    Science.gov (United States)

    Tran, Hoai Nam; Münnich, Kai; Fricke, Klaus; Harborth, Peter

    2014-01-01

    Mechanical-biological treatment (MBT) techniques have been used to reduce the emission potential of waste before placement in landfills for a couple of years, especially in Europe. The main focus of MBT is on the reduction of native organic substances and not on nitrogen compounds. As a result, the concentrations of organic substances in leachate from MBT landfills are considerably reduced in comparison to leachates from municipal solid waste landfills, while the ammonia nitrogen concentrations remain at a high level. From the stabilization of old landfills it is well known that recirculation of leachate and supplementary aeration can reduce emissions to an acceptable level in a comparatively short time. In a series of laboratory-scale tests the efficiency of this technique for MBT residues was investigated under different boundary conditions. While the effect of leachate recirculation is also well known for MBT residues, the additional aeration has so far not been investigated. The results show that this technique has only a limited influence on the reduction of organic carbon compounds. In view of nitrogen compounds, only the additional aeration during recirculation shows a strong effect on the quality of leachate, in which the concentrations of ammonium and total nitrogen are reduced by more than 90%. The results indicate that by using simple techniques the long-term emission behavior of MBT residues can be quickly reduced to an acceptable level. PMID:24293068

  18. Carbon Sequestration through Sustainably Sourced Algal Fertilizer: Deep Ocean Water.

    Science.gov (United States)

    Sherman, M. T.

    2014-12-01

    Drawing down carbon from the atmosphere happens in the oceans when marine plants are growing due to the use of carbon dioxide for biological processes and by raising the pH of the water. Macro- and microscopic marine photosynthesizers are limited in their growth by the availability of light and nutrients (nitrogen, phosphorous, iron, etc.) Deep ocean water (DOW), oceanic water from bellow about 1000m, is a natural medium for marine algae, which contains all (except in rare circumstances) necessary components for algal growth and represents over 90% of the volume of the ocean. The introduction of DOW to a tropical or summer sea can increase chlorophyll from near zero to 60 mg per M3 or more. The form of the utilization infrastructure for DOW can roughly be divided into two effective types; the unconstrained release and the open pond system. Unconstrained release has the advantage of having relatively low infrastructure investment and is available to any area of the ocean. The open pond system has high infrastructure costs but enables intensive use of DOW for harvesting macro- and microalgae and sustainable mariculture. It also enables greater concomitant production of DOW's other potential products such as electricity or potable water. However, unlike an unconstrained release the open pond system can capture much of the biomaterial from the water and limits the impact to the surrounding ecosystem. The Tidal Irrigation and Electrical System (TIESystem), is an open pond that is to be constructed on a continental shelf. It harnesses the tidal flux to pump DOW into the pond on the rising tide and then uses the falling tide to pump biologically rich material out of the pond. This biomaterial represents fixed CO2 and can be used for biofuel or fertilizers. The TIESystem benefits from an economy of scale that increases at a rate that is roughly equal to the relationship of the circumference of a circle (the barrier that creates the open pond) to the area of the pond

  19. Sources and sinks of carbon in boreal ecosystems of interior Alaska: a review

    Science.gov (United States)

    Douglas, Thomas A.; Jones, Miriam C.; Hiemstra, Christopher A.

    2014-01-01

    Boreal regions store large quantities of carbon but are increasingly vulnerable to carbon loss due to disturbance and climate warming. The boreal region, underlain by discontinuous permafrost, presents a challenging landscape for itemizing current and potential carbon sources and sinks in the boreal soil and vegetation. The roles of fire, forest succession, and the presence (or absence) of permafrost on carbon cycle, vegetation, and hydrologic processes have been the focus of multidisciplinary research in this area for the past 20 years. However, projections of a warming future climate, an increase in fire severity and extent, and the potential degradation of permafrost could lead to major landscape process changes over the next 20 to 50 years. This provides a major challenge for predicting how the interplay between land management activities and impacts of climate warming will affect carbon sources and sinks in Interior Alaska. To assist land managers in adapting and managing for potential changes in the Interior Alaska carbon cycle we developed this review paper incorporating an overview of the climate, ecosystem processes, vegetation types, and soil regimes in Interior Alaska with a focus on ramifications for the carbon cycle. Our objective is to provide a synthesis of the most current carbon storage estimates and measurements to support policy and land management decisions on how to best manage carbon sources and sinks in Interior Alaska. To support this we have surveyed relevant peer reviewed estimates of carbon stocks in aboveground and belowground biomass for Interior Alaska boreal ecosystems. We have also summarized methane and carbon dioxide fluxes from the same ecosystems. These data have been converted into the same units to facilitate comparison across ecosystem compartments. We identify potential changes in the carbon cycle with climate change and human disturbance including how compounding disturbances can affect the boreal system. Finally, we provide

  20. Sources of uncertainties in modelling black carbon at the global scale

    OpenAIRE

    Vignati, E.; Karl, M; M. Krol; Wilson, J.(School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom); Stier, P; F. Cavalli

    2010-01-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the...

  1. Comparative Analysis of Carbon Monoxide Modeling from Vehicular Sources in Puebla City, México

    OpenAIRE

    Sthephany Sedeño-Cisneros; María Auxilio Osorio-Lama; Miguel Ángel Valera-Pérez; René Bernardo Elías Cabrera-Cruz

    2015-01-01

    The results of dispersion modeling of carbon monoxide are reported in this paper. The results of applying the technique of Rapid Assessment of Sources of Environmental Pollution (RASEP) database and the Air Monitoring State System in the City of Puebla, México, were employed. Concentrations of carbon monoxide emitted by cars inferred by RASAP technique with those reported by the environmental monitoring station “Nymphs”, were compared. The date of 21 June 2005-2010 was se...

  2. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype

    OpenAIRE

    Ruslana Vasylkovska; Natalia Petriv; Halyna Semchyshyn

    2015-01-01

    Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i) hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii) the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii) meta...

  3. Morphology and Electrochemical Properties of Thermal Modified Nanoporous Carbon as Electrode of Lithium Power Sources

    Directory of Open Access Journals (Sweden)

    V.I. Mandzyuk

    2014-04-01

    Full Text Available The paper explored the effect of thermal modification on morphology of porous carbon material and specific energy parameters of lithium power sources formed on it bases. The structural and sorption properties of these materials – specific surface area, micropore surface, total pore volume, micropore volume, average pore diameter, are defined by low-temperature porometry method. The electro-stimulated diffusion coefficient of lithium ions into porous carbon material is calculated on the bases of galvanostatic intermittent titration.

  4. Carbon sources supporting a diverse fish community in a tropical coastal ecosystem (Gazi Bay, Kenya)

    OpenAIRE

    Nyunja, J.; Ntiba, M.; Onyari, J.; Mavuti, K.; K. Soetaert; BOUILLON, S

    2009-01-01

    Interlinked mangrove-seagrass ecosystems are characteristic features of many tropical coastal areas, where they act as feeding and nursery grounds for a variety of fishes and invertebrates. The autotrophic carbon sources supporting fisheries in Gazi bay (Kenya) were studied in three sites, two located in the tidal creeks flowing through extensive mangrove forests, another site located in the subtidal seagrass meadows, approximately 2.5 km away from the forest. Carbon and nitrogen stable isoto...

  5. Comparison of various sources of high surface area carbon prepared by different types of activation

    International Nuclear Information System (INIS)

    Activated carbon has been known as an excellent adsorbent and is widely used due to its large adsorption capacity. Activation condition and types of activation influence the surface area and porosity of the activated carbon produced. In this study, palm kernel shells and commercially activated carbon were used. To convert palm kernel shells into coal, two methods were employed, namely chemical activation and physical activation. For chemical activation, two activating agents, zinc chloride and potassium carbonate, were used. The activated carbons were analyzed using Fourier Transform Infrared (FTIR) spectroscopy, single point BET and free emission scanning electron microscopy (FESEM). The commercial activated carbon was also characterized. FTIR results indicate that all the palm kernel shells were successfully converted to carbon. Single point BET surface area of all the carbons prepared were obtained. From FESEM micrograph, the chemically activated palm kernel shells shows well highly defined cavities and pores. This study also shows that palm kernel shells can be used to be a better source of high surface area carbon. (author)

  6. Comparison of different polysaccharides as carbon source for super capacitor electrodes

    International Nuclear Information System (INIS)

    The Philippine is one of the world's largest producers of carrageenan, a sulfated polysaccharide extracted from indigenous seaweed varieties. Aside from its traditional food and dairy uses, carrageenan may be a source of carbon for high performance super capacitor. A super capacitor is an energy storage device similar to batteries. It is also known as electrochemical double layer capacitor (EDLC). The charge is stored in the electrochemical double layer at the electrode-electrolyte interface. High capacitance is achieved because of the high surface area of the carbon material that is typically used. In this study, carbonized materials from kappa-and iota-carrageenan were compared with other polysaccharide such as sodium alginate and chitosan. Carbonization was done by pyrolysis of the polysaccharide under flowing nitrogen at 600 degree centigrade for 3 hours. The carbonized materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, BET surface area analysis and cyclic voltammetry. The carbonization yields for the different polysaccharide range from 36 to 72% with no particular trend with respect to type of polysaccharide. The FTR spectra show the expected polar functionalities typical of activated carbon which show vibration frequencies of C=O at 1650 cm-1 and C-O stretching around 1000-1200 cm-1. The CV measurements using the carbonized material as working electrode ar different cycling rates between -200 mV to 500 mV relative to Ag/AgC1 reference electrode show capacitive behavior for the carbon derived from the carrageenans. (author)

  7. Characteristics and source of black carbon aerosol over Taklimakan Desert

    Institute of Scientific and Technical Information of China (English)

    FU; S.Joshua

    2010-01-01

    Black carbon(BC) and PM10 in the center of the Taklimakan Desert were online monitored in the whole year of 2007.In addi-tion,TSP samples were also synchronously daily collected by medium-volume samplers with Whatman41 filters in the spring of 2007.BC in the dust aerosol was up to 1.14%of the total mass of PM10.A remarkable seasonal variation of BC in the aerosol was observed in the order of winter>spring>autumn>summer.The peak value of BC appeared at midnight while the lowest one in the evening each day,which was just the reverse of that in the urban area.The contribution of BC to the total mass of PM10 on non-dust storm days was~11 times of that in dust storm.Through back trajectory and principal component analysis,it was found that BC in the dust aerosol over Taklimakan Desert might be attributed to the emission from the anthropogenic activities,including domestic heating,cooking,combustion of oil and natural gas,and the medium-range transport from those oases located in the margins of the desert.The total BC aerosol from the Taklimakan Desert to be transported to the eastward downstream was estimated to be 6.3×104 ton yr-1.

  8. Interaction between afternoon aeration and tilapia stocking density

    OpenAIRE

    Francisco Roberto dos Santos Lima; Davi de Holanda Cavalcante; Vanessa Tomaz Rebouças; Marcelo Vinícius do Carmo e Sá

    2016-01-01

    The present study aimed at determining the effects of the interaction between afternoon aeration and stocking density of Nile tilapia on variables of water and soil quality, growth performance and effluent quality. The experiment was a 3 x 2 factorial randomized block design, with three stocking densities (8, 12 and 16 fish per tank or 43.5, 65.3, and 87.0 g m-3) under two mechanical aeration regimes, absence (control; three replicates) and afternoon aeration (four replicates). The afternoon ...

  9. Research on Aeration Systems Efficiency in Small Wastewater Treatment Plants

    OpenAIRE

    Ala Sokolova

    2011-01-01

    Large amount of small wastewater treatment plants does not work properly. One of the reasons could be wrong design of the aeration system. Therefore, the aim of this research is to analyse the performance of two aeration systems used in Lithuanian small wastewater treatment plants. Both aeration systems are designed for the following parameters: 4 PE and 0,8 m3/d wastewater flow. These data correspond to the oxygen requirement of 40,9 g O2/h. Summarizing the results of the research, it was fo...

  10. Biotechnological Production of Docosahexaenoic Acid Using Aurantiochytrium limacinum: Carbon Sources Comparison And Growth Characterization.

    Science.gov (United States)

    Abad, Sergi; Turon, Xavier

    2015-12-01

    Aurantiochytrium limacinum, a marine heterotrophic protist/microalga has shown interesting yields of docosahexaenoic acid (DHA) when cultured with different carbon sources: glucose, pure and crude glycerol. A complete study in a lab-scale fermenter allowed for the characterization and comparison of the growth kinetic parameters corresponding to each carbon source. Artificial Marine Medium (AMM) with glucose, pure and crude glycerol offered similar biomass yields. The net growth rates (0.10-0.12 h(-1)), biomass (0.7-0.8 g cells/g Substrate) and product (0.14-0.15 g DHA/g cells) yields, as well as DHA productivity were similar using the three carbon sources. Viable potential applications to valorize crude glycerol are envisioned to avoid an environmental problem due to the excess of byproduct. PMID:26690180

  11. Biotechnological Production of Docosahexaenoic Acid Using Aurantiochytrium limacinum: Carbon Sources Comparison And Growth Characterization

    Directory of Open Access Journals (Sweden)

    Sergi Abad

    2015-12-01

    Full Text Available Aurantiochytrium limacinum, a marine heterotrophic protist/microalga has shown interesting yields of docosahexaenoic acid (DHA when cultured with different carbon sources: glucose, pure and crude glycerol. A complete study in a lab-scale fermenter allowed for the characterization and comparison of the growth kinetic parameters corresponding to each carbon source. Artificial Marine Medium (AMM with glucose, pure and crude glycerol offered similar biomass yields. The net growth rates (0.10–0.12 h−1, biomass (0.7–0.8 g cells/g Substrate and product (0.14–0.15 g DHA/g cells yields, as well as DHA productivity were similar using the three carbon sources. Viable potential applications to valorize crude glycerol are envisioned to avoid an environmental problem due to the excess of byproduct.

  12. Sources and delivery of carbon dioxide for enhanced oil recovery. Final report, October 1977--December 1978

    Energy Technology Data Exchange (ETDEWEB)

    Hare, M.; Perlich, H.; Robinson, R.; Shah, M.; Zimmerman, F.

    1978-12-01

    Results are presented from a comprehensive study by Pullman Kellogg, with assistance from Gulf Universities Research Consortium (GURC) and National Cryo-Chemics Incorporated (NCI), of the carbon dioxide supply situation for miscible flooding operations to enhance oil recovery. A survey of carbon dioxide sources within the geographic areas of potential EOR are shown on four regional maps with the tabular data for each region to describe the sources in terms of quantity and quality. Evaluation of all the costs, such as purchase, production, processing, and transportation, associated with delivering the carbon dioxide from its source to its destination are presented. Specific cases to illustrate the use of the maps and cost charts generated in this study have been examined.

  13. [Effect of PLA/starch slow-release carbon source on biological denitrification].

    Science.gov (United States)

    Tang, Dan-Qi; Wang, Juan; Zheng, Tian-Long; Liu, Jian-Guo; Wang, Qun-Hui

    2014-06-01

    We used polylactic acid (PLA) and starch to develop a slow-release carbon source and biofilm carrier by blending and fusing techniques for removing nitrate contamination from groundwater, investigated the changes of nitrate, nitrite concentrations and COD in denitrification process supplied by the slow-release carbon source in different mass ratios [PLA/starch (P: S) were 8:2, 7:3, 6:4, 5:5, respectively]. The experimental results demonstrated that the best mass ratio of PLA/starch was 5:5, resulting in a nitrate removal rate of more than 99%. A high denitrification performance was achieved in continuous fixed-bed reactor, the effluent nitrate concentration was below 2 mg x L(-1). These experiments provide scientific basis for the development of environmentally-friendly and controllable slow-release carbon source. PMID:25158501

  14. Biogas purification using membrane micro-aeration: A mass transfer analysis

    Directory of Open Access Journals (Sweden)

    Wathsala Perera, Deshai Botheju, Rune Bakke

    2014-01-01

    Full Text Available When sulfur containing organic feedstocks undergo anaerobic digestion, sulfides are formed due to the biological activities of sulfur reducing bacteria. Presence of hydrogen sulfide (H2S negatively affects the usage of biogas and needs to be reduced to levels that depend on the intended biogas application. Conversion of sulfide to its oxidized forms can be carried out by aerobic chemolithotrophic bacteria consuming oxygen as the electron acceptor. Membrane micro-aeration is a recently developed reliable method of safely supplying oxygen into anaerobic digesters. In this study, mass transfer models are developed to represent diffusion and back diffusion of gases through tubular polydimethylsiloxane (PDMS membranes. The models are utilized to determine the required membrane area and length in order to supply the stoichiometric amount of oxygen for biologically oxidizing a given amount of sulfide feed into elemental sulfur. Penetration of oxygen and nitrogen into the digester and transfer of methane, carbon dioxide and hydrogen sulfide back into the membrane tube are analyzed using these mass transfer models. Circulating air or aerated water inside the membrane tube is considered as two alternatives for supplying micro-aeration to the digester. Literature digester performance and sulfide data are used for example calculations. The required membrane length depends on circulating water flow rates and dissolved oxygen concentrations when water is used inside the membrane. A considerable fraction of CO2 can also be removed from the biogas in this case. Circulating air inside the membrane is, however, more promising solution as it requires much less membrane area and thereby also causes insignificant methane loss. The proposed membrane micro-aeration technique cuts N2 biogas dilution in half compared to direct air purging for in-situ sulfide oxidation.

  15. Hydroxyl radical induced degradation of salicylates in aerated aqueous solution

    International Nuclear Information System (INIS)

    Ionizing radiation induced degradation of acetylsalicylic acid, its hydrolysis product salicylic acid and a salicylic acid derivative 5-sulpho-salicylic acid, was investigated in dilute aqueous solutions by UV–vis spectrophotometry, HPLC separation and diode-array or MS/MS detection, chemical oxygen demand, total organic carbon content and by Vibrio fischeri toxicity measurements. Hydroxyl radicals were shown to degrade these molecules readily, and first degradation products were hydroxylated derivatives in all cases. Due to the by-products, among them hydrogen peroxide, the toxicity first increased and then decreased with the absorbed dose. With prolonged irradiation complete mineralization was achieved. - Highlights: • In OH induced reactions of salicylates first products are hydroxylated derivatives. • With prolonged irradiation dihydroxy derivatives also form. • In aerated solutions the one-electron oxidant OH induces 3–4 oxidations. • Toxicity first increases and then decreases with dose mainly due to H2O2 formation. • The toxicity in tap water is smaller than in pure water

  16. Secondary organic carbon quantification and source apportionment of PM10 in Kaifeng, China

    Institute of Scientific and Technical Information of China (English)

    WU Lin; FENG Yinchang; WU Jianhui; ZHU Tan; BI Xiaohui; HAN Bo; YANG Weihong; YANG Zhiqiang

    2009-01-01

    During 2005, the filter samples of ambient PM10 from five sites and the source samples of particulate matter were collected in Kaifeng, Henan province of China. Nineteen elements, water-soluble ions, total carbon (TC) and organic carbon (OC) contained in samples were analyzed. Seven contributive source types were identified and their contributions to ambient PM10 were estimated by chemical mass balance (CMB) receptor model. Weak associations between the concentrations of organic carbon and element carbon (EC) were observed during the sampling periods, indicating that there was secondary organic aerosol pollution in the urban atmosphere. An indirect method of "OC/EC minimum ratio" was applied to estimate the concentration of secondary organic carbon (SOC). The results showed that SOC contributed 26.2%, 32.4% and 18.0% of TC in spring, summer-fall and winter respectively, and the annual average SOC concentration was 7.07 μg/m3, accounting for 5.73% of the total mass in ambient PM10. The carbon species concentrations in ambient PM10 were recalculated by subtracting the SOC concentrations from measured concentrations of TC and OC to increase the compatibility of source and receptor measurements for CMB model.

  17. Feasibility of automatic aeration for insect pest management for rice stored in East Texas

    Science.gov (United States)

    Aeration using automatic controllers was compared with manually-activated aeration (manual aeration) in bins of farm-stored rice in Nome, TX, from 17 September 2002 through the end of the year. Manual aeration was defined as the farm owner activating the fans manually in mid-October, while automati...

  18. The effects of different carbon sources on biosynthesis of pectinolytic enzymes by Aspergillus niger

    Directory of Open Access Journals (Sweden)

    Kiro Mojsov

    2010-11-01

    Full Text Available The aim of this work was to investigate the effects of different carbon sources on the nourishing base on the production of pectinolytic enzymes by Aspergillus niger with the aim of optimizing the medium for maximal enzyme production. Growth and enzymes production by Aspergillus niger were evaluated on glucose, fructose, galactose, xylose, lactose, apple pectin and the dry apple pulp. Results of different carbon sources on base showed maximal endo-pectinolytic activity, endo-PG/328 U L-1 with the pressed apple pulp, compared with endo-PG/140 U L-1 with apple pectin, endo-PG/62 U L-1 with galactose, endo-PG/28 U L-1 with lactose, endo-PG/0.0 U L-1 with glucose and fructose and endo-PG/5.0 U L-1 without carbon source (control. The growth of the microorganism (dry biomass on different carbon sources showed maximum dry biomass, 4.5 g L-1 with glucose, compared with dry biomass, 4.3 g L-1 with fructose, 4.0 g L-1 with the pressed apple pulp, 3.5 g L-1 with galactose, 3.0 g L-1 with lactose, 2.2 g L-1 with apple pectin and 0.8 g L-1 without carbon source (control. Maximal endo-PG production, 328 U L-1 and dry biomass, 4.0 g L-1 by fungus Aspergillus niger was observed in a medium at pH initial, 4.0. The results presented here will be of commercial importance for using apple pulp as a carbon source for production of pectinolytic enzymes in submerged fermentation.

  19. Amorphous carbon film deposition on inner surface of tubes using atmospheric pressure pulsed filamentary plasma source

    OpenAIRE

    Pothiraja, Ramasamy; Bibinov, Nikita; Awakowicz, Peter

    2011-01-01

    Uniform amorphous carbon film is deposited on the inner surface of quartz tube having the inner diameter of 6 mm and the outer diameter of 8 mm. A pulsed filamentary plasma source is used for the deposition. Long plasma filaments (~ 140 mm) as a positive discharge are generated inside the tube in argon with methane admixture. FTIR-ATR, XRD, SEM, LSM and XPS analyses give the conclusion that deposited film is amorphous composed of non-hydrogenated sp2 carbon and hydrogenated sp3 carbon. Plasma...

  20. Evaluation of Natural Materials as Exogenous Carbon Sources for Biological Treatment of Low Carbon-to-Nitrogen Wastewater

    Science.gov (United States)

    Ramírez-Godínez, Juan; Beltrán-Hernández, Icela; Álvarez-Hernández, Alejandro; Coronel-Olivares, Claudia; Contreras-López, Elizabeth; Quezada-Cruz, Maribel; Vázquez-Rodríguez, Gabriela

    2015-01-01

    In the bacterial processes involved in the mitigation of nitrogen pollution, an adequately high carbon-to-nitrogen (C : N) ratio is key to sustain denitrification. We evaluated three natural materials (woodchips, barley grains, and peanut shells) as carbon sources for low C : N wastewater. The amount of organic matter released from these materials to aqueous media was evaluated, as well as their pollution swapping potential by measuring the release of total Kjeldahl nitrogen, N-NH4+, NO2−, and NO3−, and total phosphorous. Barley grains yielded the highest amount of organic matter, which also showed to be the most easily biodegradable. Woodchips and peanut shells released carbon rather steadily and so they would not require frequent replenishment from biological reactors. These materials produced eluates with lower concentrations of nutrients than the leachates from barley grains. However, as woodchips yielded lower amounts of suspended solids, they constitute an adequate exogenous source for the biological treatment of carbon-deficient effluents. PMID:26495313

  1. Sources of uncertainties in modelling Black Carbon at the global scale

    Directory of Open Access Journals (Sweden)

    F. Cavalli

    2009-11-01

    Full Text Available Our understanding of the global black carbon cycle is essentially qualitative due to uncertainties in our knowledge of the properties of black carbon. This work investigates uncertainties related to modelling black carbon: due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and due to the uncertainties in the definition and quantification of observed black carbon, which propagate through to both the emission inventories, and the measurements used for the model evaluation.

    The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering black carbon as bulk aerosol and a simple treatment in the removal and (ii a more complete description of microphysical aging within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol. In the first approach a fixed 70% of black carbon is scavenged in clouds and removed when rain is present. The second leads to a global average of 40% black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, showing that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of magnitude.

  2. The effect of various carbon sources on the growth of single-celled cyanophyta

    Science.gov (United States)

    Avilov, I. A.; Sidorenkova, E. S.

    1983-01-01

    In 19 strains of unicellular blue-green algae, belonging to general Synechococcus, Synechocystis, Aphanocapsa and Aphanothece, the capacity of growth under mixotrophic conditions in mineral media with organic carbon sources (carbohydrates, polyols) was investigated. At moderate light intensity (1200 lx) and 0.5% of carbon source there was revealed: (1) Stimulation of growth; (2) Partial or complete inhibition of growth; (3) No influence of carbohydrate and polyols on the growth of some algae strains. Three physiological groups for the investigated strains have been outlined on the basis of data obtained. The possibility of using the differences revealed in classification of unicellular blue-green algae is discussed.

  3. Carbon nanotube based X-ray sources: Applications in pre-clinical and medical imaging

    International Nuclear Information System (INIS)

    Field emission offers an alternate method of electron production for Bremsstrahlung based X-ray tubes. Carbon nanotubes (CNTs) serve as very effective field emitters, allowing them to serve as electron sources for X-ray sources, with specific advantages over traditional thermionic tubes. CNT derived X-ray sources can create X-ray pulses of any duration and frequency, gate the X-ray pulse to any source and allow the placement of many sources in close proximity. We have constructed a number of micro-CT systems based on CNT X-ray sources for applications in small animal imaging, specifically focused on the imaging of the heart and lungs. This paper offers a review of the pre-clinical applications of the CNT based micro-CT that we have developed. We also discuss some of the current and potential clinical applications of the CNT X-ray sources.

  4. CO2 mitigation potential of mineral carbonation with industrial alkalinity sources in the United States.

    Science.gov (United States)

    Kirchofer, Abby; Becker, Austin; Brandt, Adam; Wilcox, Jennifer

    2013-07-01

    The availability of industrial alkalinity sources is investigated to determine their potential for the simultaneous capture and sequestration of CO2 from point-source emissions in the United States. Industrial alkalinity sources investigated include fly ash, cement kiln dust, and iron and steel slag. Their feasibility for mineral carbonation is determined by their relative abundance for CO2 reactivity and their proximity to point-source CO2 emissions. In addition, the available aggregate markets are investigated as possible sinks for mineral carbonation products. We show that in the U.S., industrial alkaline byproducts have the potential to mitigate approximately 7.6 Mt CO2/yr, of which 7.0 Mt CO2/yr are CO2 captured through mineral carbonation and 0.6 Mt CO2/yr are CO2 emissions avoided through reuse as synthetic aggregate (replacing sand and gravel). The emission reductions represent a small share (i.e., 0.1%) of total U.S. CO2 emissions; however, industrial byproducts may represent comparatively low-cost methods for the advancement of mineral carbonation technologies, which may be extended to more abundant yet expensive natural alkalinity sources. PMID:23738892

  5. Effect of different carbon sources on the biological phosphorus removal by a sequencing batch reactor using pressurized pure oxygen

    OpenAIRE

    Wei, Jie; Imai, Tsuyoshi; Higuchi, Takaya; Arfarita, Novi; YAMAMOTO, Koichi; Sekine, Masahiko; Kanno, Ariyo

    2014-01-01

    The effect of different carbon source on the efficiency of enhanced biological phosphorus removal (EBPR) from synthetic wastewater with acetate and two ratios of acetate/starch as a carbon source was investigated. Three pressurized pure oxygen sequencing batch reactor (POSBR) experiments were operated. The reactors (POSBR1, POSBR2 and POSBR3) were developed and studied at different carbon source ratios of 100% acetate, 75% acetate plus 25% starch and 50% acetate plus 50% starch, respectively....

  6. At neutral pH the chronological lifespan of Hansenula polymorpha increases upon enhancing the carbon source concentrations

    OpenAIRE

    Adam Kawałek; van der Klei, Ida J

    2014-01-01

    Dietary restriction is generally assumed to increase the lifespan in most eukaryotes, including the simple model organism Saccharomyces cerevisiae. However, recent data questioned whether this phenomenon is indeed true for yeast. We studied the effect of reduction of the carbon source concentration on the chronological lifespan of the yeast Hansenula polymorpha using four different carbon sources. Our data indicate that reduction of the carbon source concentration has a negative (glucose, eth...

  7. Comparison of Energy Dissipation with and without Aerators

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Experimental results showed that aerators increase the energy dissipation of the flow in the channel by reducing the velocity coefficient φ in the deflector bucket and the jet-trajectory length, by increasing energy dissipation of the jet flow in the air and the diffusion length of the jet falling into the pool and by reducing the energy intensity of the jet falling into the pool. The energy dissipation prevents wash out downstream.When air is not entrained in the water flow, the aerators act as artificial irregularities in the channel. The energy dissipation due to the aerators in the channel without entrained air is greater than when air is entrained in the water flow.Correlations of the experimental data can be used to estimate the energy dissipation effect of the aerators on the outlet structure for the three test cases.

  8. EVALUATION OF AERATION/CIRCULATION AS A LAKE RESTORATION TECHNIQUE

    Science.gov (United States)

    Artificial circulation and hypolimnetic aeration are management techniques for oxygenating eutrophic lakes subject to water quality problems, algal blooms, and fishkills. Artificial circulation is achieved by injecting diffused air into lower waters, by mechanial pumping of water...

  9. Immune response and disease resistance of shrimp fed biofloc grown on different carbon sources.

    Science.gov (United States)

    Ekasari, Julie; Hanif Azhar, Muhammad; Surawidjaja, Enang H; Nuryati, Sri; De Schryver, Peter; Bossier, Peter

    2014-12-01

    The objective of this study was to document the immunological effects of growing shrimp in biofloc systems. The experiment consisted of four types of biofloc systems in which bioflocs were produced by daily supplementation of four different carbon sources, i.e. molasses, tapioca, tapioca-by-product, and rice bran, at an estimated C/N ratio of 15 and a control system without any organic carbon addition. Each biofloc system was stocked with Pacific white shrimp (Litopenaeus vannamei) juveniles that were reared for 49 days. The use of tapioca-by-product resulted in a higher survival (93%) of the shrimp as compared to the other carbon sources and the control. The highest yield and protein assimilation was observed when tapioca was used as the carbon source. After 49 days, phenoloxidase (PO) activity of the shrimp grown in all biofloc systems was higher than that of the shrimp from the control system. Following a challenge test by injection with infectious myonecrosis virus (IMNV), the levels of PO and respiratory burst (RB) activity in the shrimp of all biofloc treatments were higher than that of the challenged shrimp from the control treatment. An increased immunity was also suggested by the survival of the challenged shrimp from the experimental biofloc groups that was significantly higher as compared to the challenged shrimp from the control treatment, regardless of the organic carbon source used to grow the bioflocs. Overall, this study demonstrated that the application of biofloc technology may contribute to the robustness of cultured shrimp by immunostimulation and that this effect is independent of the type of carbon source used to grow the flocs. PMID:25218685

  10. Sources of uncertainties in modelling black carbon at the global scale

    Directory of Open Access Journals (Sweden)

    E. Vignati

    2010-03-01

    Full Text Available Our understanding of the global black carbon (BC cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the measurements used for the model evaluation.

    The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering BC as bulk aerosol and a simple treatment of the removal with fixed 70% of in-cloud black carbon concentrations scavenged by clouds and removed when rain is present and (ii a more complete description of microphysical ageing within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol, which results in a global average of 40% in-cloud black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer atmospheric lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, indicating that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of

  11. Source apportionment of atmospheric particulate carbon in Las Vegas, Nevada,USA

    Institute of Scientific and Technical Information of China (English)

    Mark C.Green; Judith C.Chow; M.-C.Oliver Chang; L.-W.Antony Chen; Hampden D.Kuhns; Vicken R.Etyemezian; John G.Watson

    2013-01-01

    A study was conducted to quantify wintertime contributions of source types to carbonaceous PM2.5 at four urban sites in the Las Vegas Valley,one of the most rapidly growing urban areas in the southwestern United States.Twenty-four hour average ambient samples were collected for mass,ions,elements,organic carbon (OC),elemental carbon (EC),and trace organic markers analysis.Additional measurements were made to determine diurnal patterns in light-absorbing black carbon (BC) as a marker for combustion sources.Carbonaceous PM sources of on-road gasoline vehicles,on-road diesel vehicles,and off-road diesel engines were characterized with their chemical profiles,as well as fuel-based emission factors,using an In-Plume Sampling System.The Effective Variance Chemical Mass Balance (EV-CMB) source apportionment model was applied to the ambient samples collected,using source profiles developed in this study as well as profiles from other relevant studies.Four main sources contributed to PM2.5 carbon within the Las Vegas Valley:(1) paved road dust,(2) on-road gasoline vehicles,(3) residential wood combustion,and (4) on-road diesel vehicles.CMB estimated that on-road mixed fleet gasoline vehicles are the largest source for OC and EC at all the sites.The contribution of paved road dust to both OC and EC was 5-10% at the four sites.On-road diesel vehicles contribute 22% of the OC and 34% of the EC at a site near the city center,which is located immediately downwind of a major freeway.Residential wood combustion is a more important source than on-road diesel vehicles for two residential neighborhood sites.These results are consistent with our conceptual model,and the research methodology may be applied to studying other urban areas.

  12. Latitudinal distribution of the sources of carbon monoxide in the troposphere

    International Nuclear Information System (INIS)

    We have constructed a vertically and zonally averaged model of the troposphere which calculates photochemical interactions and diffusive North-South transport of trace species. The model can be used to calculate the latitudinal distribution of the source function of a species if its concentration distribution is known. We have applied this procedure to carbon monoxide and find large sources outside the industrialized belt in the Northern Hemisphere

  13. Primary Nutritional Content of Bio-Flocs Cultured with Different Organic Carbon Sources and Salinity

    OpenAIRE

    JULIE EKASARI; ROSELIEN CRAB; WILLY VERSTRAETE

    2010-01-01

    Application of bio-flocs technology (BFT) in aquaculture offers a solution to avoid environmental impact of high nutrient discharges and to reduce the use of artificial feed. In BFT, excess of nutrients in aquaculture systems are converted into microbial biomass, which can be consumed by the cultured animals as a food source. In this experiment, upconcentrated pond water obtained from the drum filter of a freshwater tilapia farm was used for bio-flocs reactors. Two carbon sources, sugar and g...

  14. Effect of dissolved oxygen on nitrate removal using polycaprolactone as an organic carbon source and biofilm carrier in fixed-film denitrifying reactors.

    Science.gov (United States)

    Luo, Guozhi; Xu, Guimei; Gao, Jinfang; Tan, Hongxin

    2016-05-01

    Nitrate-nitrogen (NO3(-)-N) always accumulates in commercial recirculating aquaculture systems (RASs) with aerobic nitrification units. The ability to reduce NO3(-)-N consistently and confidently could help RASs to become more sustainable. The rich dissolved oxygen (DO) content and sensitive organisms stocked in RASs increase the difficulty of denitrifying technology. A denitrifying process using biologically degradable polymers as an organic carbon source and biofilm carrier was proposed because of its space-efficient nature and strong ability to remove NO3(-)-N from RASs. The effect of dissolved oxygen (DO) levels on heterotrophic denitrification in fixed-film reactors filled with polycaprolactone (PCL) was explored in the current experiment. DO conditions in the influent of the denitrifying reactors were set up as follows: the anoxic treatment group (Group A, average DO concentration of 0.28±0.05mg/L), the low-oxygen treatment DO group (Group B, average DO concentration of 2.50±0.24mg/L) and the aerated treatment group (Group C, average DO concentration of 5.63±0.57mg/L). Feeding with 200mg/L of NO3(-)-N, the NO3(-)-N removal rates were 1.53, 1.60 and 1.42kg/m(3) PCL/day in Groups A, B and C, respectively. No significant difference in NO3(-)-N removal rates was observed among the three treatments. It was concluded that the inhibitory effects of DO concentrations lower than 6mg/L on heterotrophic denitrification in the fixed-film reactors filled with PCL can be mitigated. PMID:27155419

  15. Treatment of sewage sludge in a thermophilic membrane reactor (TMR) with alternate aeration cycles.

    Science.gov (United States)

    Collivignarelli, Maria Cristina; Castagnola, Federico; Sordi, Marco; Bertanza, Giorgio

    2015-10-01

    The management of sewage sludge is becoming a more and more important issue, both at national and international level, in particular due to the uncertain recovery/disposal future options. Therefore, it is clear that the development of new technologies that can mitigate the problem at the source by reducing sludge production is necessary, such as the European Directive 2008/98/EC prescribes. This work shows the results obtained with a thermophilic membrane reactor, for processing a biological sludge derived from a wastewater treatment plant (WWTP) that treats urban and industrial wastewater. Sewage sludge was treated in a thermophilic membrane reactor (TMR), at pilot-scale (1 m(3) volume), with alternate aeration cycles. The experimentation was divided into two phases: a "startup phase" during which, starting with a psychrophilic/mesophilic biomass, thermophilic conditions were progressively reached, while feeding a highly biodegradable substrate; the obtained thermophilic biomass was then used, in the "regime phase", to digest biological sludge which was fed to the plant. Good removal yields were observed: 64% and 57% for volatile solids (VS) and total COD (CODtot), respectively, with an average hydraulic retention time (HRT) equal to 20 d, an organic loading rate (OLR) of about 1.4-1.8 kg COD m(-3) d(-1) and aeration/non aeration cycles alternated every 4 h. PMID:26233586

  16. CAVITATION CONTROL BY AERATION AND ITS COMPRESSIBLE CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-yong; SU Pei-lan

    2006-01-01

    This paper presents an experimental investigation and a theoretical analysis of cavitation control by aeration and its compressible characteristics at the flow velocity V=20m/s-50m/s. Pressure waveforms with and without aeration in cavitation region were measured. The variation of compression ratio with air concentration was described, and the relation between the least air concentration to prevent cavitation erosion and flow velocity proposed based on our experimental study. The experimental results show that aeration remarkably increases the pressure in cavitation region, and the corresponding pressure wave exhibits a compression wave/shock wave. The pressure increase in cavitation region of high-velocity flow with aeration is due to the fact that the compression waves/shock wave after the flow is aerated. The compression ratio increases with air concentration rising. The relation between flow velocity and least air concentration to prevent cavitation erosion follows a semi-cubical parabola. Also, the speed of sound and Mach number of high-velocity aerated flow were analyzed.

  17. Effect of aeration on fast gas pressure tests

    Institute of Scientific and Technical Information of China (English)

    CHEN Yu-jia; JIANG Cheng-lin; LI Xiao-wei; TANG Jun; WANG Chen; YANG Fei-long; WANG Fa-kai; ZHANG Chao-jie; DENG Shu-hua

    2009-01-01

    Given the problem of the long time required for testing gas pressure, we propose a fast-test method in which we used a technique of fast borehole sealing and air replenishing. Based on the characteristics of gas emission from boreholes to be tested, we built a theoretical model for calculating parameters during the process of increasing natural pressure and aeration. Using this model, we investigated the effect of different aeration conditions on velocity of pressure tests. The result shows that: 1) aerating air into boreholes can speed up gas pressure tests and 2) the more similar the pressure of the aerated air to the original gas pressure, the smaller the gas volume absorbed by coal and the shorter the time needed in pressure test. A case study in the Lu'an mining area shows that the time needed for gas pressure test is only 4 h using our method of aeration and 29 h under conditions of increasing natural pressure, saving time by 86.2%. This case study also indicates that, by using the aeration method, only one hour is needed for gas pressure to reach a stable state, which breaks the record of the shortest time needed for gas pressure tests in China.

  18. Relative Contributions of Fossil and Contemporary Carbon sources to PM 2.5 Aerosols at Nine IMPROVE Network Sites

    Energy Technology Data Exchange (ETDEWEB)

    Bench, G; Fallon, S; Schichtel, B; Malm, W; McDade, C

    2006-06-26

    Particulate matter aerosols contribute to haze diminishing vistas and scenery at National Parks and Wilderness Areas within the United States. To increase understanding of the sources of carbonaceous aerosols at these settings, the total carbon loading and {sup 14}C/C ratio of PM 2.5 aerosols at nine IMPROVE (Interagency Monitoring for Protection Of Visual Environments) network sites were measured. Aerosols were collected weekly in the summer and winter at one rural site, two urban sites, five sites located in National Parks and one site located in a Wildlife Preserve. The carbon measurements together with the absence of {sup 14}C in fossil carbon materials and the known {sup 14}C/C levels in contemporary carbon materials were used to derive contemporary and fossil carbon contents of the particulate matter. Contemporary and fossil carbon aerosol loadings varied across the sites and suggest different percentages of carbon source inputs. The urban sites had the highest fossil carbon loadings that comprised around 50% of the total carbon aerosol loading. The Wildlife Preserve and National Park sites together with the rural site had much lower fossil carbon loading components. At these sites, variations in the total carbon aerosol loading were dominated by non-fossil carbon sources. This suggests that reduction of anthroprogenic sources of fossil carbon aerosols may result in little decrease in carbonaceous aerosol loading at many National Parks and rural areas.

  19. Effect of carbon source on growth and lipid accumulation in Chlorella sorokiniana GXNN01

    Institute of Scientific and Technical Information of China (English)

    QIAO Hongjin; WANG Guangce

    2009-01-01

    Heterotrophic culture of microalgae to develop methods of increasing biomass productivity and storage lipids has brought new insight to commercial biodiesel production. To understand the relationship between heterotrophy and lipid production, the effects of carbon sources on the growth and lipid accumulation of Chlorella sorokiniana GXNN01 was studied. The alga exhibited an increased growth rate in response to the addition of carbon sources, which reached the stationary phase after 48 h at 30°C. In addition, glucose and NaAc had a significant effect on the lipid accumulation during the early-stationary phase. Specifically, the lipid content was 0.237±0.026 g g~(-1) cell dry weight and 0.272±0.041 g L~(-1) when glucose was used as the carbon source, whereas the lipid content reached 0.287±0.018 g g~(-1) cell dry weight and 0.288±0.008 g L~(-1) when NaAc was used as the carbon source. The neutral lipid content was found to first decrease and then increase over time during the growth phase. A glucose concentration of 20 mmol L~(-1) gave the maximal lipid yield and the optimum harvest time was the early-stationary phase.

  20. Expression of xylanases of anaerobic rumen fungi depending on carbon source in medium

    Czech Academy of Sciences Publication Activity Database

    Novotná, Zuzana; Fliegerová, Kateřina; Šimůnek, Jiří

    Clermont - Ferrand: INRA, 2008. s. 1-1. [6th INRA - RRI SYMPOSIUM: Gut microbiome . 18.06.2010 - 20.06.2008, Clermont - Ferrand] Institutional research plan: CEZ:AV0Z50450515 Keywords : xylanases * fungi * carbon source Subject RIV: EH - Ecology, Behaviour

  1. Influence of carbon source on alpha-amylase production by Aspergillus oryzae

    DEFF Research Database (Denmark)

    Carlsen, Morten; Nielsen, Jens

    2001-01-01

    The influence of the carbon source on a-amylase production by Aspergillus oryzae was quantified in carbon-limited chemostat cultures. The following carbon sources were investigated: maltose, maltodextrin (different chain lengths), glucose, fructose, galactose, sucrose, glycerol, mannitol and...... on sucrose, fructose, glycerol, mannitol and acetate. During growth on acetate there was no production of alpha -amylase, whereas addition of small amounts of glucose resulted in alpha -amylase production. A possible induction by alpha -methyl-D-glucoside during growth on glucose was also...... investigated, but this compound was not found to be a better inducer of alpha -amylase production than glucose. The results strongly indicate that besides acting as a repressor via the CreA protein, glucose acts as an inducer....

  2. Application of carbon isotope for discriminating sources of soil CO2 in karst area, Guizhou

    Institute of Scientific and Technical Information of China (English)

    黎廷宇; 王世杰

    2001-01-01

    Using carbon isotope of soil CO2 this paper discussed the sources of soil CO2 in karst area, Guizhou Province, China. Oxidation-decomposition of organic matter, respiration of plant root and activity of microbe are thought to be the major sources of soil CO2. However, in karst area, the contribution of dissolution of underlying carbonate rock to soil CO2 should be considered as in acidic environment. Atmospheric CO2 is the major composition of soil CO2 in surface layer of soil profiles and its proportion in soil CO2 decreases with increase of soil depth. CO2 produced by dissolution of carbonate rock contributes 34%-46% to soil CO2 below the depth of 10cm in the studied soil profiles covered by grass.

  3. Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 2. Modeling carbon sources, sinks, and δ13C evolution

    Science.gov (United States)

    McMahon, Peter B.; Chapelle, Francis H.

    1991-01-01

    Stable isotope data for dissolved inorganic carbon (DIC), carbonate shell material and cements, and microbial CO2 were combined with organic and inorganic chemical data from aquifer and confining-bed pore waters to construct geochemical reaction models along a flowpath in the Black Creek aquifer of South Carolina. Carbon-isotope fractionation between DIC and precipitating cements was treated as a Rayleigh distillation process. Organic matter oxidation was coupled to microbial fermentation and sulfate reduction. All reaction models reproduced the observed chemical and isotopic compositions of final waters. However, model 1, in which all sources of carbon and electron-acceptors were assumed to be internal to the aquifer, was invalidated owing to the large ratio of fermentation CO2 to respiration CO2 predicted by the model (5–49) compared with measured ratios (two or less). In model 2, this ratio was reduced by assuming that confining beds adjacent to the aquifer act as sources of dissolved organic carbon and sulfate. This assumption was based on measured high concentrations of dissolved organic acids and sulfate in confining-bed pore waters (60–100 μM and 100–380 μM, respectively) relative to aquifer pore waters (from less than 30 μM and 2–80 μM, respectively). Sodium was chosen as the companion ion to organic-acid and sulfate transport from confining beds because it is the predominant cation in confining-bed pore waters. As a result, excessive amounts of Na-for-Ca ion exchange and calcite precipitation (three to four times more cement than observed in the aquifer) were required by model 2 to achieve mass and isotope balance of final water. For this reason, model 2 was invalidated. Agreement between model-predicted and measured amounts of carbonate cement and ratios of fermentation CO2 to respiration CO2 were obtained in a reaction model that assumed confining beds act as sources of DIC, as well as organic acids and sulfate. This assumption was

  4. Methane-derived authigenic carbonates of mid-Cretaceous age in southern Tibet: Types of carbonate concretions, carbon sources, and formation processes

    Science.gov (United States)

    Liang, Huimin; Chen, Xi; Wang, Chengshan; Zhao, Dekun; Weissert, Helmut

    2016-01-01

    Methane-derived authigenic carbonates with distinctive structures and morphologies have been documented worldwide, but they are rarely found from ancient strata in the Eastern Tethys Ocean. The methane-derived authigenic carbonates found in southern Tibet are developed in calcareous or silty shales of mid-Cretaceous age in the Xigaze forearc basin and in the Tethyan Himalaya tectonic zone. The morphology, mineralogy, elemental geochemistry and composition of carbon and oxygen isotopes of these carbonates are studied in detail. The carbonates have nodular, tubular, and tabular morphologies. They are primarily composed of carbonate cement that binds and partly replaces host sediment grains; host siliciclastic sediments are composed mainly of quartz and plagioclase feldspar; a few foraminifers; and framboidal or subhedral to euhedral pyrite. Carbonate cements dominantly are micritic calcite, with minor contribution of dolomite. Nodular concretions are characterized by depleted δ13C values, commonly ranging from -30‰ to -5‰. The δ13C values show a gradual decrease from the periphery to the center, and the CaO, SiO2, Fe2O3, Al2O3, K2O, and TiO2 contents generally show a gradual change. These features indicate that the nodular concretions grew from an early-formed center toward the periphery, and that the carbon source of the nodular concretions was derived from a mixture of methane, methanogenic CO2, and seawater-dissolved inorganic carbon. The tubular concretions are characterized by δ13C values of -8.85‰ to -3.47‰ in the Shangba Section, and -27.37‰ to -23.85‰ in the upper Gamba Section. Unlike the nodular concretions, the tubular concretions show central conduits, which are possible pathways of methane-rich fluids, suggesting that the cementation of tubular concretions begins at the periphery and proceeds inward. Moreover, the tubular concretions show morphological similarity with the methane-derived carbonate chimneys, pipes and slabs reported in

  5. Fate of Pathogen Indicators During Extended Aeration Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Norshuhaila Mohamed Sunar

    2015-05-01

    Full Text Available Pathogen indicators normally used in water quality indicator because large numbers of the bacteria are always present in the faeces of humans, but are not naturally found in water. Since these bacteria don’t live long in water once outside the intestine, their presence in water means there has been recent contamination through effluent discharges or other sources. Like other enteric pathogens, a common mode of transmission for E.coli is via contaminated water, food and by direct person to person contact. Infection often causes severe bloody diarrhea, abdominal cramps, and possibly fever.  In some cases, infection can lead to kidney failure and possibly death. In order to evaluate the effieciency of extended aeration wastewater treatment plant (EAWWTP, the microbial analyses such as enumeration of E.coli and total coliform were measured. Besides, this study also involved the measurements of pH, turbidity, DO (Dissolve Oxygen, BOD (Biochemical Oxygen Demand, COD (Chemical Oxygen Demand and TSS (Total Suspended Solid. This study summarized that each treatment process provides important roles to overall effieciency of EAWWTP. The secondary treatment was proved sufficient not only on reducing pathogen indicators but for all examined parameters. Significantly, this study conclude that numbers of pathogen indicators discharges in effluent meet the regulated standard guideline after treated through the EAWWTP.

  6. Comparative study on CO2 sources in soil developed on carbonate rock and non-carbonate rock in Central Guizhou

    Institute of Scientific and Technical Information of China (English)

    黎廷宇; 王世杰; 郑乐平

    2002-01-01

    In this paper, by using concentration and carbon stable isotope the.CO2 sources of soil profiles developed on limestone, dolostone and claystone basements in Central Guizhou, China are comparatively studied. The results show that CO2 concentration of soil profiles developed on different basements is different, having the following sequence: limestone>dolostone>claystone. Below the soil depth of 20 cm from the surface the δ13C value of CO2 in soil profile developed on limestone ranges from -12.811‰ - -13.492‰(PDB), that in soil profile developed on dolostone varys from -13.212‰--14.271‰(PDB) and that in soil profile developed on claystone is about -20.234‰- -21.485‰(PDB). Taking the carbon isotope of soil organic matter and carbonate rock as two isotopic endmembers, the proportion of soil C02 generated by dissolution of carbonate rock is calculated, about 21%-25% for soil profile developed on limestone basement, 19%-21% for soil profile developed on dolostone basement. There is almost no influx of

  7. Advanced Electron Beam Ion Sources (EBIS) for 2-nd generation carbon radiotherapy facilities

    International Nuclear Information System (INIS)

    In this work we analyze how advanced Electron Beam Ion Sources (EBIS) can facilitate the progress of carbon therapy facilities. We will demonstrate that advanced ion sources enable operation of 2-nd generation ion beam therapy (IBT) accelerators. These new accelerator concepts with designs dedicated to IBT provide beams better suited for therapy and, are more cost efficient than contemporary IBT facilities. We will give a sort overview of the existing new IBT concepts and focus on those where ion source technology is the limiting factor. We will analyse whether this limitation can be overcome in the near future thanks to ongoing EBIS development

  8. Advanced Electron Beam Ion Sources (EBIS) for 2-nd generation carbon radiotherapy facilities

    Science.gov (United States)

    Shornikov, A.; Wenander, F.

    2016-04-01

    In this work we analyze how advanced Electron Beam Ion Sources (EBIS) can facilitate the progress of carbon therapy facilities. We will demonstrate that advanced ion sources enable operation of 2-nd generation ion beam therapy (IBT) accelerators. These new accelerator concepts with designs dedicated to IBT provide beams better suited for therapy and, are more cost efficient than contemporary IBT facilities. We will give a sort overview of the existing new IBT concepts and focus on those where ion source technology is the limiting factor. We will analyse whether this limitation can be overcome in the near future thanks to ongoing EBIS development.

  9. Methods of analysis for complex organic aerosol mixtures from urban emission sources of particulate carbon

    International Nuclear Information System (INIS)

    Organic aerosols comprise approximately 30% by mass of the total fine particulate matter present in urban atmospheres. The chemical composition of such aerosols is complex and reflects input from multiple sources of primary emissions to the atmosphere, as well as from secondary production of carbonaceous aerosol species via photochemical reactions. To identify discrete sources of fine carbonaceous particles in urban atmospheres, analytical methods must reconcile both bulk chemical and molecular properties of the total carbonaceous aerosol fraction. This paper presents an overview of the analytical protocol developed and used in a study of the major sources of fine carbon particles emitted to an urban atmosphere. 23 refs., 1 fig., 2 tabs

  10. Mass spectrometry of refractory black carbon particles from six sources: carbon-cluster and oxygenated ions

    Directory of Open Access Journals (Sweden)

    J. C. Corbin

    2013-10-01

    Full Text Available We discuss the major mass spectral features of different types of refractory carbonaceous particles, ionized after laser vapourization with an Aerodyne High-Resolution Soot-Particle Aerosol Mass Spectrometer (SP-AMS. The SP-AMS was operated with a switchable 1064 nm laser and a 600 °C thermal vapourizer, yielding respective measurements of the refractory and non-refractory particle components. Six samples were investigated, all of which were composed primarily of refractory material: fuel-rich and fuel-lean propane/air diffusion-flame combustion particles; graphite-spark-generated particles; a commercial Fullerene-enriched Soot; Regal Black, a commercial carbon black; and nascent aircraft-turbine combustion particles. All samples exhibited a spectrum of carbon-cluster ions Cxn+ in their refractory mass spectrum. Smaller clusters (xxn+ distribution. For Fullerene Soot, fuel-rich-flame particles and spark-generated particles, significant Cxn+ clusters at x≫6 were present, with significant contributions from multiply-charged ions (n>1. In all six cases, the ions C1+ and C3+ contributed over 60% to the total C1x+ intensity. Furthermore, the ratio of these major ions C1+/C3+ could be used to predict whether significant Cxn+ signals with x>5 were present. When such signals were present, C1+/C3+ was close to 1. When absent, C1+/C3+ was Significant refractory oxygenated ions such as CO+ and CO2+ were also observed for all samples. We discuss these signals in detail for Regal Black, and describe their formation via decomposition of oxygenated moieties incorporated into the refractory carbon structure. These species may be of importance in atmospheric processes such as water uptake, aging and heterogeneous chemistry.

  11. A new step aeration approach towards the improvement of nitrogen removal in a full scale Carrousel oxidation ditch.

    Science.gov (United States)

    Jin, Pengkang; Wang, Xianbao; Wang, Xiaochang; Ngo, Huu Hao; Jin, Xin

    2015-12-01

    Two aeration modes, step aeration and point aeration, were used in a full-scale Carrousel oxidation ditch with microporous aeration. The nitrogen removal performance and mechanism were analyzed. With the same total aeration input, both aeration modes demonstrated good nitrification outcomes with the average efficiency in removing NH4(+)-N of more than 98%. However, the average removal efficiencies for total nitrogen were 89.3% and 77.6% under step aeration and point aeration, respectively. The results indicated that an extended aerobic zone followed the aeration zones could affect the proportion of anoxic and oxic zones. The step aeration with larger anoxic zones indicated better TN removal efficiency. More importantly, step aeration provided the suitable environment for both nitrifiers and denitrifiers. The diversity and relative abundance of denitrifying bacteria under the step aeration (1.55%) was higher than that under the point aeration (1.12%), which resulted in an overall higher TN removal efficiency. PMID:26363498

  12. Morphogenesis and Production of Enzymes by Penicillium echinulatum in Response to Different Carbon Sources

    Directory of Open Access Journals (Sweden)

    Willian Daniel Hahn Schneider

    2014-01-01

    Full Text Available The effect of different carbon sources on morphology and cellulase and xylanase production of Penicillium echinulatum was evaluated in this work. Among the six carbon sources studied, cellulose and sugar cane bagasse were the most suitable for the production of filter paper activity, endoglucanases, xylanases, and β-glucosidases. However, sucrose and glucose showed β-glucosidase activities similar to those obtained with the insoluble sources. The polyacrylamide gels proved the enzymatic activity, since different standards bands were detected in the media mentioned above. Regarding morphology, it was observed that the mycelium in a dispersed form provided the greatest enzymatic activity, possibly due to greater interaction between the substrate and hyphae. These data are important in understanding the physiology of fungi and could contribute to obtaining enzyme with potential application in the technology of second generation ethanol.

  13. Isotopic evidence of magmatism and a sedimentary carbon source at the Endeavour hydrothermal system

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T A; Proskurowski, G; Lilley, M D

    2004-01-07

    Stable and radiocarbon isotope measurements made on CO{sub 2} from high temperature hydrothermal vents on the Endeavour Segment of the Juan de Fuca Ridge indicate both magmatic and sedimentary sources of carbon to the hydrothermal system. The Endeavour segment is devoid of overlying sediments and has shown no observable signs of surficial magmatic activity during the {approx}20 years of ongoing studies. The appearance of isotopically heavy, radiocarbon dead CO{sub 2} after a 1999 earthquake swarm requires that this earthquake event was magmatic in origin. Evidence for a sedimentary organic carbon source suggests the presence of buried sediments at the ridge axis. These findings, which represent the first temporally coherent set of radiocarbon measurements from hydrothermal vent fluids, demonstrate the utility of radiocarbon analysis in hydrothermal studies. The existence of a sediment source at Endeavour and the occurrence of magmatic episodes illustrate the extremely complex and evolving nature of the Endeavour hydrothermal system.

  14. Denitrification on internal carbon sources in RAS is limited by fibers in fecal waste of rainbow trout

    NARCIS (Netherlands)

    Meriac, A.; Eding, E.H.; Kamstra, A.; Busscher, J.P.; Schrama, J.W.; Verreth, J.A.J.

    2014-01-01

    Denitrification on internal carbon sources offers the advantage to control nitrate levels in recirculating aquaculture systems (RAS) by using the fecal carbon produced within the husbandry system. However, it is not clear to which extent fecal carbon can be utilized by the microbial community within

  15. Characterization of Odorant Compounds from Mechanical Aerated Pile Composting and Static Aerated Pile Composting.

    Science.gov (United States)

    Kumari, Priyanka; Lee, Joonhee; Choi, Hong-Lim

    2016-04-01

    We studied airborne contaminants (airborne particulates and odorous compounds) emitted from compost facilities in South Korea. There are primarily two different types of composting systems operating in Korean farms, namely mechanical aerated pile composting (MAPC) and aerated static pile composting (SAPC). In this study, we analyzed various particulate matters (PM10, PM7, PM2.5, PM1, and total suspended particles), volatile organic compounds and ammonia, and correlated these airborne contaminants with microclimatic parameters, i.e., temperature and relative humidity. Most of the analyzed airborne particulates (PM7, PM2.5, and PM1) were detected in high concentration at SAPC facilities compered to MAPC; however these differences were statistically non-significant. Similarly, most of the odorants did not vary significantly between MAPC and SAPC facilities, except for dimethyl sulfide (DMS) and skatole. DMS concentrations were significantly higher in MAPC facilities, whereas skatole concentrations were significantly higher in SAPC facilities. The microclimate variables also did not vary significantly between MAPC and SAPC facilities, and did not correlate significantly with most of the airborne particles and odorous compounds, suggesting that microclimate variables did not influence their emission from compost facilities. These findings provide insight into the airborne contaminants that are emitted from compost facilities and the two different types of composting agitation systems. PMID:26949962

  16. Application of biogenic carbon dioxide produced by yeast with different carbon sources for attraction of mosquitoes towards adult mosquito traps.

    Science.gov (United States)

    Sukumaran, D; Ponmariappan, S; Sharma, Atul K; Jha, Hemendra K; Wasu, Yogesh H; Sharma, Ajay K

    2016-04-01

    Surveillance is a prime requisite for controlling arthropod vectors like mosquitoes that transmit diseases such as malaria, dengue and chikungunya. Carbon dioxide (CO2) is one of the main cues from vertebrate breath that attracts mosquitoes towards the host. Hence, CO2 is used as an attractant during surveillance of mosquitoes either from commercial cylinders or dry ice for mosquito traps. In the present study, the biogenic carbon dioxide production was optimized with different carbon sources such as glucose, simple sugar and jaggery with and without yeast peptone dextrose (YPD) media using commercial baker's yeast. The results showed that yeast produced more biogenic CO2 with simple sugar as compared to other carbon sources. Further substrate concentration was optimized for the continuous production of biogenic CO2 for a minimum of 12 h by using 10 g of baker's yeast with 50 g of simple sugar added to 1.5 l distilled water (without YPD media) in a 2-l plastic bottle. This setup was applied in field condition along with two different mosquito traps namely Mosquito Killing System (MKS) and Biogents Sentinel (BGS) trap. Biogenic CO2 from this setup has increased the trapping efficiency of MKS by 6.48-fold for Culex quinquefasciatus, 2.62-fold for Aedes albopictus and 1.5-fold for Anopheles stephensi. In the case of BGS, the efficiency was found to be increased by 3.54-fold for Ae. albopictus, 4.33-fold for An. stephensi and 1.3-fold for Armigeres subalbatus mosquitoes. On the whole, plastic bottle setup releasing biogenic CO2 from sugar and yeast has increased the efficiency of MKS traps by 6.38-fold and 2.74-fold for BGS traps as compared to traps without biogenic CO2. The present study reveals that, among different carbon sources used, simple sugar as a substance (which is economical and readily available across the world) yielded maximum biogenic CO2 with yeast. This setup can be used as an alternative to CO2 cylinder and dry ice in any adult mosquito traps to

  17. Prairie restoration and carbon sequestration: difficulties quantifying C sources and sinks using a biometric approach.

    Science.gov (United States)

    Cahill, Kimberly Nicholas; Kucharik, Christopher J; Foley, Jonathan A

    2009-12-01

    We investigated carbon cycling and ecosystem characteristics among two prairie restoration treatments established in 1987 and adjacent cropland, all part of the Conservation Reserve Program in southwestern Wisconsin, USA. We hypothesized that different plant functional groups (cool-season C3 vs. warm-season C4 grasses) between the two prairie restoration treatments would lead to differences in soil and vegetation characteristics and amount of sequestered carbon, compared to the crop system. We found significant (P soil CO2 respiration and above- and belowground productivity, but no significant differences in long-term (approximately 16-year) carbon sequestration. We used a biometric approach aggregating short-term observations of above- and belowground productivity and CO2 respiration to estimate total net primary production (NPP) and net ecosystem production (NEP) using varied methods suggested in the literature. Net ecosystem production is important because it represents the ecosystem carbon sequestration, which is of interest to land managers and policymakers seeking or regulating credits for ecosystem carbon storage. Such a biometric approach would be attractive because it might offer the ability to rapidly assess the carbon source/sink status of an ecosystem. We concluded that large uncertainties in (1) estimating aboveground NPP, (2) determining belowground NPP, and (3) partitioning soil respiration into microbial and plant components strongly affect the magnitude, and even the sign, of NEP estimates made from aggregating its components. A comparison of these estimates across treatments could not distinguish differences in NEP, nor the absolute sign of the overall carbon balance. Longer-term quantification of carbon stocks in the soil, periodically linked to measurements of individual processes, may offer a more reliable measure of the carbon balance in grassland systems, suitable for assigning credits. PMID:20014587

  18. Carbon isotope (14C, 12C) measurements to quantify sources of atmospheric carbon monoxide in urban air

    International Nuclear Information System (INIS)

    Atmospheric air samples were collected during the Winter of 1989-90 in Albuquerque, NM USA, for carbon isotope (14C, 12C) analysis of carbon monoxide (CO). An experimental sample design was prepared to target periods when the concentration of CO exceeds the 9 μL/L (volume fraction), 8 hour National Ambient Air Quality Standard (NAAQS) and during periods of attainment. Sampling sites, time of day, sampling duration, and meteorology were carefully considered so that source impacts be optimal. A balanced sampling factorial design was used to yield maximum information from the constraints imposed; the number of samples was limited by the number of sample canisters available, time, and resources. Carbon isotope measurements of urban air, ''clean-air'' background from Niwot Ridge, Colorado, average (wood) logs and oxygenated-gasolines were used in a 3-source model to calculate the contribution of woodburning to the total atmospheric CO burden in Albuquerque. Results show that the estimated fractional contribution of residential wood combustion (Θ' RWC) ranged from 0 to 0.30 of CO concentrations corrected for ''clean-air'' background. For these same samples, the respective CO concentrations attributed to woodburning range from 0 to 0.90 μmol/mol (mole fraction), well below the NAAQS. In all cases, fossil CO is the predominant source of ambient CO concentrations ranging from 0.96 to 6.34 μmol/mol. A final comment is made on the potential of fossil CO measurements as an indirect tracer of atmospheric benzene, relevant to exposure risk estimates of motor vehicle emissions and occupational health and safety standards. (author). 26 refs, 3 figs, 4 tabs

  19. Controlled Carbon Source Addition to an Alternating Nitrification-Denitrification Wastewater Treatment Process Including Biological P Removal

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens

    1995-01-01

    The paper investigates the effect of adding an external carbon source on the rate of denitrification in an alternating activated sludge process including biological P removal. Two carbon sources were examined, acetate and hydrolysate derived from biologically hydrolyzed sludge. Preliminary batch ...

  20. Influence of carbon source on alpha-amylase production by Aspergillus oryzae.

    Science.gov (United States)

    Carlsen, M; Nielsen, J

    2001-10-01

    The influence of the carbon source on alpha-amylase production by Aspergillus oryzae was quantified in carbon-limited chemostat cultures. The following carbon sources were investigated: maltose, maltodextrin (different chain lengths), glucose, fructose, galactose, sucrose, glycerol, mannitol and acetate. A. oryzae did not grow on galactose as the sole carbon source, but galactose was co-metabolized together with glucose. Relative to that on low glucose concentration (below 10 mg/l), productivity was found to be higher during growth on maltose and maltodextrins, whereas it was lower during growth on sucrose, fructose, glycerol, mannitol and acetate. During growth on acetate there was no production of alpha-amylase, whereas addition of small amounts of glucose resulted in alpha-amylase production. A possible induction by alpha-methyl-D-glucoside during growth on glucose was also investigated, but this compound was not found to be a better inducer of a-amylase production than glucose. The results strongly indicate that besides acting as a repressor via the CreA protein, glucose acts as an inducer. PMID:11759683

  1. Spatial distribution and sources of organic carbon in the surface sediment of Bosten Lake, China

    Science.gov (United States)

    Yu, Z. T.; Wang, X. J.; Zhang, E. L.; Zhao, C. Y.; Liu, X. Q.

    2015-11-01

    Lake sediment is an important carbon reservoir. However, little is known on the dynamics and sources of sediment organic carbon in Bosten Lake. We collected 13 surface (0-2 cm) sediment samples in Bosten Lake and analyzed total organic carbon (TOC), total nitrogen (TN), stable carbon isotopic composition in TOC (δ13Corg), and grain size. We found a large spatial variability in TOC content (1.8-4.4 %) and δ 13Corg value (-26.77 to -23.98 ‰). Using a three-end-member mixing model with measured TOC : TN ratio and δ13Corg, we estimated that 54-90 % of TOC was from autochthonous sources. Higher TOC content (> 3.7 %) was found in the east and central-north sections and near the mouth of the Kaidu River, which was attributable to allochthonous, autochthonous plus allochthonous, and autochthonous sources, respectively. The lowest TOC content was found in the mid-west section, which might be a result of high kinetic energy levels. Our study indicated that the spatial distribution of sediment TOC in the Bosten Lake was influenced by multiple and complex processes.

  2. Denitrification potential enhancement by addition of external carbon sources in a pre-denitrification process

    Institute of Scientific and Technical Information of China (English)

    PENG Yong-zhen; MA Yong; WANG Shu-ying

    2007-01-01

    The aim of this study is to investigate the denitrification potential enhancement by addition of external carbon sources and to estimate the denitrification potential for the predenitrification system using nitrate utilization rate(NUR)batch tests.It is shown that the denitrification potential Can be substantially increased with the addition of three external carbon sources,i.e.methanol,ethanol,and acetate.and the denitrification rates of ethanol,acetate,and methanol reached up to 9.6,12,and 3.2 mgN/(gVSS·h),respectively,while mat of starch wastewater was only 0.74 mgN/(gVSS·h).By comparison,ethanol was found to be the best extemal carbon source.NUR batch tests with starch wastewater and waste ethanol were carried out.The denitrification potential increased from 5.6 to 16.5 mg NO.-N/L owing to waste ethanol addition.By means of NUR tests,the wastewater characteristics and kinetic parameters can be estimated.which are used to determine the denitrification potential of wastewater,to calculate the denitrification potential of the plant and to predict the nitrate effluent quality,as well as provide information for developing carbon dosage conlxol strategy.

  3. Synthesis of LiFePO_4/C Composite Cathode Materials Using High Surface Area Carbon as Carbon Sources

    Institute of Scientific and Technical Information of China (English)

    George; Ting-kuo; Fey; Kai-Lun; Chiang

    2007-01-01

    1 Results The pyrolyzed product of peanut shells was utilized as a carbon source to synthesize a LiFePO4/C composite.The advantages of using agricultural wastes such as peanut shells are low costs,easy processing,and environmentally benigness.Peanut shell was first treated with a porogenic agent to produce a precursor with high porosity and surface area (>2 000 m2·g-1).A small amount of precursor was mixed with LiFePO4 fine powders and heated.The optimum calcination process for synthesizing LiFePO4/C co...

  4. Sources of carbon and sulfur nutrition for consumers in three meromictic lakes of New York State

    Science.gov (United States)

    Fry, B.; Hayes, J. M. (Principal Investigator)

    1986-01-01

    The trophic importance of bacterioplankton as a source of carbon and sulfur nutrition for consumers in meromictic lakes was tested using stable carbon (delta 13C) and sulfur (delta 34S) isotopic measurements. Studies in three lakes near Syracuse, New York, showed that most consumers ultimately derive their C and S nutrition from a mixture of terrestrial detritus, phytoplankton, and littoral vegetation, rather than from bacterioplankton. Food webs in these meromictic lakes are thus similar to those in other lakes that lack dense populations of bacterioplankton.

  5. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype

    Directory of Open Access Journals (Sweden)

    Ruslana Vasylkovska

    2015-01-01

    Full Text Available Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii metabolic and growth rates as well as catalase activity play an important role in H2O2-induced hormetic response in yeast.

  6. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype.

    Science.gov (United States)

    Vasylkovska, Ruslana; Petriv, Natalia; Semchyshyn, Halyna

    2015-01-01

    Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i) hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii) the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii) metabolic and growth rates as well as catalase activity play an important role in H2O2-induced hormetic response in yeast. PMID:26843865

  7. Effect of source gas chemistry on tribological performance of diamond-like carbon films.

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, A.; Eryilmaz, O. L.; Fenske, G. R.; Nilufer, I. B.

    1999-08-23

    In this study, we investigated the effects of various source gases (i. e., methane, ethane, ethylene, acetylene and methane + hydrogen) on friction and wear performance of diamond-like carbon (DLC) films. Specifically, we described the anomalous nature and fundamental friction and wear mechanisms of DLC films derived from gas discharge plasmas with very low to very high hydrogen content. The films were deposited on steel substrates by a plasma enhanced chemical vapor deposition process at room temperature and the tribological tests were performed in dry nitrogen. The results of tribological tests revealed a close correlation between the friction and wear coefficients of the DLC films and the source gas chemistry. Specifically, films grown in source gases with higher hydrogen-to-carbon ratios had much lower friction coefficients and wear rates than the films derived from source gases with lower hydrogen-to-carbon ratios. The lowest friction coefficient (0.002) was achieved with a film derived from 25% methane--75% hydrogen while the films derived from acetylene had a coefficient of 0.15. Similar correlations were observed on wear rates. Specifically, the films derived from hydrogen rich plasmas had the least wear while the films derived from pure acetylene suffered the highest wear. We used a combination of scanning and transmission electron microscopy and Raman spectroscopy to characterize the structural chemistry of the resultant DLC films.

  8. Tracing carbon sources through aquatic and terrestrial food webs using amino acid stable isotope fingerprinting.

    Science.gov (United States)

    Larsen, Thomas; Ventura, Marc; Andersen, Nils; O'Brien, Diane M; Piatkowski, Uwe; McCarthy, Matthew D

    2013-01-01

    Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ(13)C patterns among amino acids (δ(13)CAA) could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ(13)CAA patterns in contrast to bulk δ(13)C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ(13)CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ(13)C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ(13)C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs. PMID:24069196

  9. Tracing carbon sources through aquatic and terrestrial food webs using amino acid stable isotope fingerprinting.

    Directory of Open Access Journals (Sweden)

    Thomas Larsen

    Full Text Available Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ(13C patterns among amino acids (δ(13CAA could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ(13CAA patterns in contrast to bulk δ(13C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ(13CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ(13C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ(13C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs.

  10. Primary Nutritional Content of Bio-Flocs Cultured with Different Organic Carbon Sources and Salinity

    Directory of Open Access Journals (Sweden)

    JULIE EKASARI

    2010-09-01

    Full Text Available Application of bio-flocs technology (BFT in aquaculture offers a solution to avoid environmental impact of high nutrient discharges and to reduce the use of artificial feed. In BFT, excess of nutrients in aquaculture systems are converted into microbial biomass, which can be consumed by the cultured animals as a food source. In this experiment, upconcentrated pond water obtained from the drum filter of a freshwater tilapia farm was used for bio-flocs reactors. Two carbon sources, sugar and glycerol, were used as the first variable, and two different levels of salinity, 0 and 30 ppt, were used as the second variable. Bio-flocs with glycerol as a carbon source had higher total n-6 PUFAs (19.1 + 2.1 and 22.3 + 8.6 mg/g DW at 0 and 30 ppt, respectively than that of glucose (4.0 + 0.1 and 12.6 + 2.5 mg/g DW at 0 and 30 ppt. However, there was no effect of carbon source or salinity on crude protein, lipid, and total n-3 PUFAs contents of the bio-flocs.

  11. Molecular Dynamics Simulation of Chemical Vapor Deposition of Amorphous Carbon: Dependence on H/C Ratio of Source Gas

    OpenAIRE

    Ito, Atsushi M.; Takayama, Arimichi; Saito, Seiki; Ohno, Noriyasu; Kajita, Shin; Nakamura, Hiroaki

    2010-01-01

    By molecular dynamics simulation, the chemical vapor deposition of amorphous carbon onto graphite and diamond surfaces was studied. In particular, we investigated the effect of source H/C ratio, which is the ratio of the number of hydrogen atoms to the number of carbon atoms in a source gas, on the deposition process. In the present simulation, the following two source gas conditions were tested: one was that the source gas was injected as isolated carbon and hydrogen atoms, and the other was...

  12. Pure and aerated water entry of a flat plate

    Science.gov (United States)

    Ma, Z. H.; Causon, D. M.; Qian, L.; Mingham, C. G.; Mai, T.; Greaves, D.; Raby, A.

    2016-01-01

    This paper presents an experimental and numerical investigation of the entry of a rigid square flat plate into pure and aerated water. Attention is focused on the measurement and calculation of the slamming loads on the plate. The experimental study was carried out in the ocean basin at Plymouth University's COAST laboratory. The present numerical approach extends a two-dimensional hydro-code to compute three-dimensional hydrodynamic impact problems. The impact loads on the structure computed by the numerical model compare well with laboratory measurements. It is revealed that the impact loading consists of distinctive features including (1) shock loading with a high pressure peak, (2) fluid expansion loading associated with very low sub-atmospheric pressure close to the saturated vapour pressure, and (3) less severe secondary reloading with super-atmospheric pressure. It is also disclosed that aeration introduced into water can effectively reduce local pressures and total forces on the flat plate. The peak impact loading on the plate can be reduced by half or even more with 1.6% aeration in water. At the same time, the lifespan of shock loading is prolonged by aeration, and the variation of impulse is less sensitive to the change of aeration than the peak loading.

  13. Methanogenesis acceleration of fresh landfilled waste by micro-aeration

    Institute of Scientific and Technical Information of China (English)

    SHAO Li-ming; HE Pin-jing; ZHANG Hua; YU Xiao-hua; LI Guo-jian

    2005-01-01

    When municipal solid waste(MSW) with high content of food waste is landfilled, the rapid hydrolysis of food waste results in the imbalance of anaerobic metabolism in the landfill layer, indicated by accumulation of volatile fatty acids(VFA) and decrease of pH value.This occurrence could lead to long lag time before the initiation of methanogenesis and to the production of strong leachate. Simulated landfill columns with forced aeration, with natural ventilation, and with no aeration, were monitored regarding their organics degradation rate with leachate recirculation. Hydrolysis reactions produced strong leachate in the column with no aeration. With forced aeration, the produced VFA could be effectively degraded, leading to the reduction in COD of the leachate effluent since the week 3. The CH4 in the frequency of twice/d, could amount to 40% (v/v) after only 20 weeks. This amount had increased up to 50% afterward even with no aeration. Most of COD in the recirculated leachate was removed. Using natural ventilation, CH4 could also be produced and the COD of the leachate effluent be reduced after 10 weeks of operation. However, the persistent existence of oxygen in the landfill layer yielded instability in methanogenesis process.

  14. Amorphous carbon film deposition on inner surface of tubes using atmospheric pressure pulsed filamentary plasma source

    CERN Document Server

    Pothiraja, Ramasamy; Awakowicz, Peter

    2011-01-01

    Uniform amorphous carbon film is deposited on the inner surface of quartz tube having the inner diameter of 6 mm and the outer diameter of 8 mm. A pulsed filamentary plasma source is used for the deposition. Long plasma filaments (~ 140 mm) as a positive discharge are generated inside the tube in argon with methane admixture. FTIR-ATR, XRD, SEM, LSM and XPS analyses give the conclusion that deposited film is amorphous composed of non-hydrogenated sp2 carbon and hydrogenated sp3 carbon. Plasma is characterized using optical emission spectroscopy, voltage-current measurement, microphotography and numerical simulation. On the basis of observed plasma parameters, the kinetics of the film deposition process is discussed.

  15. MgB2 superconductors with addition of ZrB2 and different carbon sources

    International Nuclear Information System (INIS)

    MgB2 has been catching the attention due to the possibility to apply the material in magnets and electronic devices, operating with cryocoolers. In this work, MgB2 bulks were developed and analyzed with addition of ZrB2, another diboride with the same C32 hexagonal structure as MgB2, and simultaneous addition of different carbon sources (SiC, graphite, and carbon nanotubes). The objective of these additions is to modify the Mg planes with the diborides and to dope the material with carbon, improving the upper critical fields. Besides the doping of the material, this method creates crystalline defects in the superconducting matrix, which can act as pinning centers. As a result we could improve the critical current density of the material and estimate the behavior of dopants on the superconducting properties.

  16. Preparation of carbon nitride materials by polycondensation of the single-source precursor aminodichlorotriazine (ADCT)

    International Nuclear Information System (INIS)

    Carbon nitride, usually described as C3N4 or CNx (x > 1), has been reported to form disordered network structures. In this work we describe a new synthesis route using 2-amino-4,6-dichloro-s-triazine (ADCT) as a single-source precursor, adopting single step and two step decompositions. During two step polycondensation ADCT is first heated in a closed system and than fully condensed under vacuum. Our reactions yielded carbon nitride materials having compositions near C3N4. The obtained carbon nitride occurs as a brown, amorphous solid according to X-ray and electron diffraction experiments. Moreover, infrared spectra and results from 13C-NMR measurements indicate evidence for the presence of bridged heptazine and triazine units in the structure

  17. Effects of toxicity, aeration, and reductant supply on trichloroethylene transformation by a mixed methanotrophic culture.

    OpenAIRE

    Alvarez-Cohen, L; McCarty, P L

    1991-01-01

    The trichloroethylene (TCE) transformation rate and capacity of a mixed methanotrophic culture at room temperature were measured to determine the effects of time without methane (resting), use of an alternative energy source (formate), aeration, and toxicity of TCE and its transformation products. The initial specific TCE transformation rate of resting cells was 0.6 mg of TCE per mg of cells per day, and they had a finite TCE transformation capacity of 0.036 mg of TCE per mg of cells. Formate...

  18. Prioritizing low-carbon energy sources to enhance China’s energy security

    International Nuclear Information System (INIS)

    Highlights: • Four dimensions and ten metrics are used for energy security assessment. • Both qualitative and quantitative metrics are considered for energy security. • AHP has been used to quantify qualitative metrics. • TOPSIS method has been used for prioritize the low-carbon energy sources. • Sensitivity analysis and integrated ranking have been carried out. - Abstract: This paper explores how low-carbon systems compare to each other in terms of their net effect on Chinese energy security, and how they ought to be ranked and strategized into an optimal and integrated resource plan. The paper utilizes Analytic Hierarchy Process (AHP) to first determine the relative performances of hydroelectricity, wind energy, solar energy, biomass energy, and nuclear power with respect to the energy security dimensions of availability, affordability, accessibility, and acceptability. Both qualitative and quantitative metrics are considered. It relies on AHP to calculate the relative weights of the qualitative metrics attached to these dimensions of energy security for each of our five low carbon energy sources. Then, energy security performance is determined by aggregating multiple, weighted metrics into a generic index based on the method of TOPSIS and then tweaked with a sensitivity analysis. Finally, an integrated method has been developed to rank the low-carbon energy systems from most to least important, with major implications for Chinese decision-makers and stakeholders. We conclude that hydroelectricity and wind power are the two low-carbon energy sources with the most potential to enhance China’s energy security. By contrast, nuclear and solar power have the least potential

  19. Direct growth and patterning of multilayer graphene onto a targeted substrate without an external carbon source.

    Science.gov (United States)

    Kang, Dongseok; Kim, Won-Jun; Lim, Jung Ah; Song, Yong-Won

    2012-07-25

    Using only a simple tube furnace, we demonstrate the synthesis of patterned graphene directly on a designed substrate without the need for an external carbon source. Carbon atoms are absorbed onto Ni evaporator sources as impurities, and incorporated into catalyst layers during the deposition. Heat treatment conditions were optimized so that the atoms diffused out along the grain boundaries to form nanocrystals at the catalyst-substrate interfaces. Graphene patterns were obtained under patterned catalysts, which restricted graphene formation to within patterned areas. The resultant multilayer graphene was characterized by Raman spectroscopy and transmission electron microscopy to verify the high crystallinity and two-dimensional nanomorphology. Finally, a metal-semiconductor diode with a catalyst-graphene contact structure were fabricated and characterized to assess the semiconducting properties of the graphene sheets with respect to the display of asymmetric current-voltage behavior. PMID:22709270

  20. Stationary scanning x-ray source based on carbon nanotube field emitters

    Science.gov (United States)

    Yang, Guang; Zhang, Jian; Cheng, Yuan; Gao, Bo; Qiu, Qi; Lee, Yueh; Lu, Jianping; Zhou, Otto

    2006-03-01

    Carbon nanotube is an ideal field emitter thanks to its large aspect ratio and small diameter. Based on its field emission property, we have developed a stationary scanning x-ray source, which can generate a scanning x-ray beam to image an object from multiple projection angles without mechanical motion. The key component of the device is a gated carbon nanotube field emission cathode with an array of electron emitting pixels that are individually addressable via a metal-oxide-semiconductor field effect transistor-based electronic circuit. The characteristics of this x-ray source are measured and its imaging capability is demonstrated. The device can potentially lead to a fast data acquisition rate for laminography and tomosynthesis.

  1. The Investments in Renewable Energy Sources: Do Low Carbon Economies Better Invest in Green Technologies?

    Directory of Open Access Journals (Sweden)

    Antonio Angelo Romano

    2011-01-01

    Full Text Available The aim of this study is to analyse the driving of investment in renewable energy sources in low carbon and high carbon economies. To address these issues, a dynamic panel analysis of the renewable investment in a sample of 29 countries was proposed. Results demonstrate that the dynamic of investments in renewable sources is similar in the two panels, and depends by nuclear power generation, GDP and technological efficiency. Results show that countries try to reduce their environmental footprint, decreasing the CO2 intensity. Based on the estimation results, we think that energy sustainability passes through the use of renewable resources that can complement the nuclear technology on condition that both exceed their limits.

  2. Isotopic anomaly for carbon ions in an electron cyclotron resonance ion source.

    Science.gov (United States)

    Drentje, A G; Kitagawa, A; Muramatsu, M

    2010-02-01

    In many experiments methods were applied to increase the highly charged ion output from an electron cyclotron resonance ion source; the gas-mixing method is still generally being applied. The dominant role of the masses of the ions in the gas-mixture was apparent. Two basically differing mechanisms could to first order explain most of the observations. A significant mass effect showed up in a mixture of oxygen isotopes, the so-called oxygen anomaly; so far that effect could be explained in zeroth order only. The anomaly was observed later for nitrogen isotopes as well. In the present experiment it is shown that the anomaly also exists for carbon isotopes, where the necessity of feeding the source with carbon-hydrogen compounds brings about an essential different experimental fact. PMID:20192439

  3. The environmental convergence hypothesis: Carbon dioxide emissions according to the source of energy

    International Nuclear Information System (INIS)

    The aim of this paper is to investigate the environmental convergence hypothesis in carbon dioxide emissions for a large group of developed and developing countries from 1980 to 2009. The novel aspect of this work is that we distinguish among carbon dioxide emissions according to the source of energy (coal, natural gas and petroleum) instead of considering the aggregate measure of per capita carbon dioxide emissions, where notable interest is given to the regional dimension due to the application of new club convergence tests. This allows us to determine the convergence behaviour of emissions in a more precise way and to detect it according to the source of energy used, thereby helping to address the environmental targets. More specifically, the convergence hypothesis is examined with a pair-wise test and another one is used to test for the existence of club convergence. Our results from using the pair-wise test indicate that carbon dioxide emissions for each type of energy diverge. However, club convergence is found for a large group of countries, although some still display divergence. These findings point to the need to apply specific environmental policies to each club detected, since specific countries converge to different clubs. - Highlights: • The environmental convergence hypothesis is investigated across countries. • We perform a pair-wise test and a club convergence test. • Results from the first of these two tests suggest that carbon dioxide emissions are diverging. • However, we find that carbon dioxide emissions are converging within groups of countries. • Active environmental policies are required

  4. External Carbon Source Addition as a Means to Control an Activated Sludge Nutrient Removal Process

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens; Søeberg, Henrik; Kymmel, Mogens

    1994-01-01

    In alternating type activated sludge nutrient removal processes, the denitrification rate can be limited by the availability of readily-degradable carbon substrate. A control strategy is proposed by which an easily metabolizable COD source is added directly to that point in the process at which...... denitrification momentarily occurs. This approach serves to increase the denitrification rate on demand, thereby allowing the accumulation of nitrate and nitrite during periods of peak nitrogen loading to be reduced or avoided. A pilot plant demonstration of the control strategy using acetate as COD source is...

  5. Deposition of diamond like carbon films by using a single ion gun with varying beam source

    Institute of Scientific and Technical Information of China (English)

    JIANG Jin-qiu; Chen Zhu-ping

    2001-01-01

    Diamond like carbon films have been successfully deposited on the steel substrate, by using a single ion gun with varying beam source. The films may appear blue, yellow and transparent in color, which was found related to contaminants from the sample holder and could be avoided. The thickness of the films ranges from tens up to 200 nanometers, and the hardness is in the range 20 to 30 GPa. Raman analytical results reveal the films are in amorphous structure. The effects of different beam source on the films structure are further discussed.

  6. Stationary scanning x-ray source based on carbon nanotube field emitters

    International Nuclear Information System (INIS)

    We report a field emission x-ray source that can generate a scanning x-ray beam to image an object from multiple projection angles without mechanical motion. The key component of the device is a gated carbon nanotube field emission cathode with an array of electron emitting pixels that are individually addressable via a metal-oxide-semiconductor field effect transistor-based electronic circuit. The characteristics of this x-ray source are measured and its imaging capability is demonstrated. The device can potentially lead to a fast data acquisition rate for laminography and tomosynthesis with a simplified experimental setup

  7. Design of an intense muon source with a carbon and mercury target

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, D.; Berg, J. S.; Neuffer, D.; Ding, X.

    2015-05-03

    In high-intensity sources, muons are produced by firing high energy protons onto a target to produce pions. The pions decay to muons which are captured and accelerated. In the present study, we examine the performance of the channel for two different target scenarios: one based on liquid mercury and another one based on a solid carbon target. We produce distributions with the two different target materials and discuss differences in particle spectrum near the sources. We then propagate the distributions through our capture system and compare the full system performance for the two target types.

  8. Source and migration of light hydrocarbons indicated by carbon isotopic ratios

    International Nuclear Information System (INIS)

    Carbon isotopic ratios can distinguish among different sources of methane and can be used to correlate maturity of sediments with the methane. This technique has been applied to several wells and the isotopic values have been used to suggest the sources of the methane and whether the methane migrated into the area. Comparison of the isotopic ratio changes in ethane, propane, and butanes indicated that isotopic fractionation of methane by migration is not a major factor. The significant changes in methane isotopic ratio and the small changes in the isotopic ratios of these heavier hydrocarbons suggest that, although diffusion is not the sole process in migration, the time for migration is moderate

  9. Design of an Intense Muon Source with a Carbon and Mercury Target

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, Diktys [Brookhaven; Berg, J. Scott [Brookhaven; Neuffer, David [Fermilab; Ding, Xiaoping [UCLA

    2015-06-01

    In high-intensity sources, muons are produced by firing high energy protons onto a target to produce pions. The pions decay to muons which are captured and accelerated. In the present study, we examine the performance of the channel for two different target scenarios: one based on liquid mercury and another one based on a solid carbon target. We produce distributions with the two different target materials and discuss differences in particle spectrum near the sources. We then propagate the distributions through our capture system and compare the full system performance for the two target types.

  10. Black carbon emissions from Russian diesel sources: case study of Murmansk

    Directory of Open Access Journals (Sweden)

    M. Evans

    2015-02-01

    Full Text Available Black carbon (BC is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture, fishing and diesel generators. For on-road transport, we conducted several surveys to understand the vehicle fleet and driving patterns, and, for all sources, we also relied on publicly available local data sets and analysis. We calculated that BC emission in Murmansk Region were 0.40 Gg in 2012. The mining industry is the largest source of BC emissions in the region, emitting 70% of all BC emissions because of its large diesel consumption and absence of emissions controls. On-road vehicles are the second largest source emitting about 12% of emissions. Old heavy duty trucks are the major source of emissions. Emission controls on new vehicles limit total emissions from on-road transportation. Vehicle traffic and fleet surveys show that many of the older cars on the registry are lightly or never used. We also estimated that total BC emissions from diesel sources in Russia were 56.7 Gg in 2010, and on-road transport contributed 55% of diesel BC emissions. Agricultural machinery is also a significant source Russia-wide, in part because of the lack of controls on off-road vehicles.

  11. Black carbon emissions from Russian diesel sources: case study of Murmansk

    Science.gov (United States)

    Evans, M.; Kholod, N.; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2015-07-01

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in the Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture), ships and diesel generators. For on-road transport, we conducted several surveys to understand the vehicle fleet and driving patterns, and, for all sources, we also relied on publicly available local data sets and analysis. We calculated that BC emissions in the Murmansk Region were 0.40 Gg in 2012. The mining industry is the largest source of BC emissions in the region, emitting 69 % of all BC emissions because of its large diesel consumption and absence of emissions controls. On-road vehicles are the second largest source, emitting about 13 % of emissions. Old heavy duty trucks are the major source of emissions. Emission controls on new vehicles limit total emissions from on-road transportation. Vehicle traffic and fleet surveys show that many of the older cars on the registry are lightly or never used. We also estimated that total BC emissions from diesel sources in Russia were 50.8 Gg in 2010, and on-road transport contributed 49 % of diesel BC emissions. Agricultural machinery is also a significant source Russia-wide, in part because of the lack of controls on off-road vehicles.

  12. Cassava stillage and its anaerobic fermentation liquid as external carbon sources in biological nutrient removal*

    OpenAIRE

    Bu, Fan; Hu, Xiang; Xie, Li; Zhou, Qi

    2015-01-01

    The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in anaerobic-anoxic-aerobic sequencing batch reactors (SBRs). Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound (sodium acetate) served as an external carbon source. Cyclic studies indicated that the cassava by-p...

  13. Can ultrasonically disintegrated activated sludge be exploited as an internal carbon source for denitrification?

    OpenAIRE

    Lambert, Nico; Smets, Ilse; Impe, Jan Van; Dewil, Raf

    2013-01-01

    The recovery of a solubilized sludge carbon source from waste activated sludge by using ultrasonic treatment or a combination of ultrasonic treatment and alkaline hydrolysis was investigated. First the release of sCOD and the associated immediate sludge reduction as a result of the ultrasonic disintegration was experimentally studied. Respirometric data were used to quantify the amount of rapidly biodegradable COD (SS) that was formed during the disintegration process. In the second phase of ...

  14. Carbon monoxide concentration in donated blood : relation to cigarette smoking and other sources

    OpenAIRE

    Åberg, Anna-Maja; Nilsson Sojka, Birgitta; Winsö, Ola; Abrahamsson, Pernilla; Johansson, Göran; Larsson, Jan Erik

    2009-01-01

    BACKGROUND: Carbon monoxide (CO) is normally present in the human body due to endogenous production of CO. CO can also be inhaled by exposure to external sources such as cigarette smoke, car exhaust, and fire. The purpose of this study was to investigate CO concentrations in blood from 410 blood donors at the blood center in Umea, Sweden. To further evaluate the effects of cigarette smoking on CO concentrations, the elimination time for CO was examined in six volunteer smokers after a smoked ...

  15. Optimization of low sulfur carob pulp liquor as carbon source for fossil fuels biodesulfurization

    OpenAIRE

    Silva, Tiago P.; Paixão, Susana M.; Teixeira, A. V.; Roseiro, J. Carlos; Alves, Luís Manuel

    2013-01-01

    Background:Biodesulfurization (BDS) is a complementary technology to hydrodesulfurization since it allows the removal of recalcitrant sulfur compounds present in fossil fuels. The cost of culture medium to produce the biocatalysts is still one limitation for BDS application. Carob pulp, as an alternative carbon source, can reduce this cost. However, the presence of sulfates is critical, since BDS is inhibited at very low concentrations. Thus, the goal of this work was to optimize the process ...

  16. Production of siderophore type chelates in Atlantic Ocean waters enriched with different carbon and nitrogen sources

    OpenAIRE

    Mawji, Edward; Gledhill, M.; Milton, J.A.; M. V. Zubkov; Thompson, Anu; Wolff, George A.; Achterberg, Eric P.

    2011-01-01

    Siderophore type chelates were detected in nutrient enriched, incubated seawater collected from different biogeographical regions of the Atlantic Ocean. Seawater was enriched with glucose and ammonium, glycine (as a source of carbon and nitrogen) or chitin and ammonium at different concentrations and incubated for up to 3 – 4 days in the dark. Siderophore type chelates were detected using high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-...

  17. Metabolic engineering of Corynebacterium glutamicum aimed at alternative carbon sources and new products

    OpenAIRE

    Volker Fritz Wendisch; Steffen Nikolaus Lindner; Ahmed Zahoor

    2012-01-01

    Corynebacterium glutamicum is well known as the amino acid-producing workhorse of fermentation industry, being used for multi-million-ton scale production of glutamate and lysine for more than 60 years. However, it is only recently that extensive research has focused on engineering it beyond the scope of amino acids. Meanwhile, a variety of corynebacterial strains allows access to alternative carbon sources and/or allows production of a wide range of industrially relevant compounds. Some of t...

  18. Organic carbon sources and transformations in mangrove sediments : a Rock-Eval pyrolysis approach

    OpenAIRE

    Marchand, Cyril; Lallier-Vergès, Elisabeth; Disnar, Jean-Robert; Kéravis, Didier

    2008-01-01

    International audience A Rock-Eval pyrolysis study was carried out on sedimentary cores and leaf and woody tissue of vascular plant species from the mangroves of French Guiana. These forests develop on moving mudbanks and have a lifetime limited to few decades before being eroded. Our main purpose was to complete the understanding of carbon cycling in this specific environment using a method that allows monitoring the depth evolution of sources and transformation of organic matter (OM) wit...

  19. Organic carbon in intertidal mangrove forests: sources and utilization by benthic invertebrates

    OpenAIRE

    BOUILLON, S; N. Koedam; Raman, A. V.; Rao, A.V.V.S.; F. Dehairs

    2001-01-01

    In contrast to the large number of studies on the trophic significance of mangrove primary production to the aquatic foodweb, there have been few attempts to provide an overview of the relative importance of different primary carbon sources to invertebrates in the intertidal mangrove habitats. Mangrove sediments from three different mangrove ecosystems (Coringa Wildlife Sanctuary in the Godavari Delta, Andhra Pradesh, India, and Galle and Pambala, Sri Lanka) were analysed for their organic ca...

  20. Optimization of probiotic lactobacillus casei ATCC 334 production using date powder as carbon source

    OpenAIRE

    Shahravy A.; Tabandeh F.; Bambai B.; Zamanizadeh H.R.; Mizani M.

    2012-01-01

    This study was conducted to optimize culture conditions for economic production of a probiotic bacterium, Lactobacillus casei ATCC 334, in which palm date powder was applied for the first time as a low-cost main carbon source. The effect of eleven factors on bacterial growth was investigated using the Taguchi experimental design, and three factors including palm date powder, tryptone and agitation rate were found to be the most significant parameters. The optimum conditions including da...

  1. Deep Sediment-Sourced Methane Contribution to Shallow Sediment Organic Carbon: Atwater Valley, Texas-Louisiana Shelf, Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Richard B. Coffin

    2015-02-01

    Full Text Available Coastal methane hydrate deposits are globally abundant. There is a need to understand the deep sediment sourced methane energy contribution to shallow sediment carbon relative to terrestrial sources and phytoplankton. Shallow sediment and porewater samples were collected from Atwater Valley, Texas-Louisiana Shelf, Gulf of Mexico near a seafloor mound feature identified in geophysical surveys as an elevated bottom seismic reflection. Geochemical data revealed off-mound methane diffusion and active fluid advection on-mound. Gas composition (average methane/ethane ratio ~11,000 and isotope ratios of methane on the mound (average δ13CCH4(g = −71.2‰; D14CCH4(g = −961‰ indicate a deep sediment, microbial source. Depleted sediment organic carbon values on mound (δ13CSOC = −25.8‰; D14CSOC = −930‰ relative to off-mound (δ13CSOC = −22.5‰; D14CSOC = −629‰ suggest deep sourced ancient carbon is incorporated into shallow sediment organic matter. Porewater and sediment data indicate inorganic carbon fixed during anaerobic oxidation of methane is a dominant contributor to on-mound shallow sediment organic carbon cycling. A simple stable carbon isotope mass balance suggests carbon fixation of dissolved inorganic carbon (DIC associated with anaerobic oxidation of hydrate-sourced CH4 contributes up to 85% of shallow sediment organic carbon.

  2. Experimental Analysis of Pressure Fluctuations behind a Bottom Aerator

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Experimental observations show that the random process of two-phase flow beh ind an aerator is an ergodic process and its amplitude distribution is similar t o a normal distribution. The maximum pressure fluctuation is at the re-attachme n t point where the jet-trajectory flow over the aerator re-attaches to bottom o f the channel, and its amplitude is 2-3 times larger than when there is no aerato r. There is a dominant frequency of 1.24 Hz in the model, but the coherence in th e frequency domain is not obvious for other frequencies beside the dominant frequ ency. There is a large vortex at the re-attachment point behind the aerator but correlation among the measurement points is not obvious in the time domain.

  3. RE-AERATION LAW OF WATER FLOW OVER SPILLWAYS

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiang-ju; LUO Lin; CHEN Yong-can; ZHAO Wen-qian

    2006-01-01

    In order to explore the re-aeration law of water flow over spillway, the transfer process of oxygen in water flow over spillway was studied. The interfacial mass transfer coefficients were obtained by experiments. The flow fields and the turbulence characteristics are simulated by numerical methods. The fractional volume of fluid model (VOF) of the air-water two phase flows was introduced to track the interface. Consequently, the quantitative expression of the interfacial mass transfer coefficients related with velocity and kinetic energy at the free surface was derived and the re-aeration model for the water flow over spillway was established. The examination with the experimental data of different conditions shows the validity of the re-aeration model for the water flow over spillways. This study will be important to evaluate the dissolved oxygen concentration and self-purification ability of rivers.

  4. Cassava stillage and its anaerobic fermentation liquid as external carbon sources in biological nutrient removal*

    Science.gov (United States)

    Bu, Fan; Hu, Xiang; Xie, Li; Zhou, Qi

    2015-01-01

    The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in anaerobic-anoxic-aerobic sequencing batch reactors (SBRs). Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound (sodium acetate) served as an external carbon source. Cyclic studies indicated that the cassava by-products not only affected the transformation of nitrogen, phosphorus, poly-β-hydroxyalkanoates (PHAs), and glycogen in the BNR process, but also resulted in higher removal efficiencies for phosphorus and nitrogen compared with sodium acetate. Furthermore, assays for phosphorus accumulating organisms (PAOs) and denitrifying phosphorus accumulating organisms (DPAOs) demonstrated that the proportion of DPAOs to PAOs reached 62.6% (Day 86) and 61.8% (Day 65) when using cassava stillage and its anaerobic fermentation liquid, respectively, as the external carbon source. In addition, the nitrate utilization rates (NURs) of the cassava by-products were in the range of 5.49–5.99 g N/(kg MLVSS∙h) (MLVSS is mixed liquor volatile suspended solids) and 6.63–6.81 g N/(kg MLVSS∙h), respectively. The improvement in BNR performance and the reduction in the amount of cassava stillage to be treated in-situ make cassava stillage and its anaerobic fermentation liquid attractive alternatives to sodium acetate as external carbon sources for BNR processes. PMID:25845364

  5. [Effects of carbon sources, temperature and electron acceptors on biological phosphorus removal].

    Science.gov (United States)

    Han, Yun; Xu, Song; Dong, Tao; Wang, Bin-Fan; Wang, Xian-Yao; Peng, Dang-Cong

    2015-02-01

    Effects of carbon sources, temperature and electron acceptors on phosphorus uptake and release were investigated in a pilot-scale oxidation ditch. Phosphorus uptake and release rates were measured with different carbon sources (domestic sewage, sodium acetate, glucose) at 25 degrees C. The results showed that the minimum phosphorus uptake and release rates of glucose were 5.12 mg x (g x h)(-1) and 6.43 mg x (g x h)(-1), respectively, and those of domestic sewage are similar to those of sodium acetate. Phosphorus uptake and release rates increased with the increase of temperature (12, 16, 20 and 25 degrees C) using sodium acetate as carbon sources. Anoxic phosphorus uptake rate decreased with added COD. Electron acceptors (oxygen, nitrate, nitrite) had significant effects on phosphorus uptake rate and their order was in accordance with oxygen > nitrate > nitrite. The mass ratio of anoxic P uptake and N consumption (P(uptake)/N (consumption)) of nitrate and nitrite were 0.96 and 0.65, respectively. PMID:26031087

  6. Thermal hydrolysis of sludge and the use of hydrolysate as carbon source for denitrification

    Energy Technology Data Exchange (ETDEWEB)

    Barlindhaug, J.

    1995-10-01

    As a consequence of the North Sea- and the Baltic Sea Treaties as well as the Wastewater Directive of the EU, several large wastewater treatment plants discharging to sensitive receiving waters have to include phosphorus as well as nitrogen removal. This thesis evaluates the so called NTH-process for nutrient removal. In this process pre-precipitation is used in front of a biological nitrogen removal step that is based on a combination of pre- and post-denitrification in moving bed biofilm reactors. The biological step is followed by a final separation step, possibly after coagulant addition. Carbon source for the post denitrification step is made available by hydrolysis of the sludge produced. The idea is that the particulate organic matter, which in a traditional pre-denitrification step would have to be enzymatically hydrolyzed, can be more efficiently hydrolyzed in a concentrated sidestream and used in a post-denitrification step. In the thesis hydrolyzed sludge is used as a carbon source for denitrification. The objective is to investigate the influence of varying hydrolysis conditions on the composition and amount of the thermal hydrolysate produced, as well as the quality of the hydrolysate as a carbon source for denitrification. 201 refs., 78 refs., 53 tabs.

  7. Production of Cyclodextrin Glycosyltransferase (CGTase by Bacillus lehensis S8 using Sago Starch as Carbon Source

    Directory of Open Access Journals (Sweden)

    Kwan-Kit Woo

    2010-01-01

    Full Text Available Production of cyclodextrin glycosyltransferase (CGTase is influenced by the reaction of the CGTase-producing strain towards various types of substrates. Variations in environmental factors such as concentrations of carbon and nitrogen sources possess significant effects on CGTase production. The present study was conducted with the prime purpose to optimise the cultivation medium in enhancing the CGTase production by a locally isolated alkalophilic Bacillus sp. The CGTase fermentation processes were performed in 250 mL Erlenmeyer flasks containing 200 mL of production medium with continuous shaking at 200 rpm and 37°C. Optimisation process was conducted by using change-a-factor-at-a-time method. From the study, an indigenous Malaysian carbon source, i.e., sago starch was found capable in improving the CGTase production with the CGTase yield of 18452 U g-1 at 0.1% w/v of starch. In addition to that, by using yeast extract as the sole nitrogen source in the medium, the CGTase excretion by the isolate is greatly enhanced as compared to the basal medium which employed two types of nitrogenous compounds. The optimised growth medium that has been successfully developed for high level of CGTase production by using the locally isolated Bacillus lehensis in 250 mL Erlenmeyer flask is comprised of (% w/v: 0.1% sago starch, 1% yeast extract, 1% sodium carbonate, 0.009% magnesium sulphate and 0.1% di-potassium hydrogen phosphate.

  8. [Constitutive expression of human angiostatin in Pichia pastoris using glycerol as only carbon source].

    Science.gov (United States)

    Tu, Fa-Zhi; Fu, Ce-Yi; Zhang, Tian-Yuan; Luo, Jin-Xian; Zhang, Ai-Lian

    2007-09-01

    Carbon source plays an important role in the constitutive expression of foreign proteins in Pichia pastoris. In present study, glucose , glycerol , methanol and oil acid, was used respectively as the only carbon source to constitutively express hAS in Pichia pastoris GS115 (pGAP9K-AS)in shaking flask. The result shows that oleic acid is the best (163 mg/L) compared with glycerol (83mg/L), glucose (76 mg/L)and methanol (57 mg/L). Since oleic acid is insoluble in water, glycerol was used as the carbon source in the high-density cell culture of GS115 (pGAP9K-AS) in a 30 liter bioreactor and 169 mg/L of angiostatin was obtained after 48h of culture. The expressed angiostatin is immunologically active as shown by Western blotting. The recombinant hAS inhibits bFGF induced CAM angiogenesis and suppresses the growth of B16 melanoma in C57BL/6J mice. The tumor inhibition rate is 90% after 12 days of treatment. Statistics analysis revealed that the tumor volume difference of mice between the hAS group and PBS group is prominent (P < 0.01). PMID:18051873

  9. Wine wastes as carbon source for biological treatment of acid mine drainage.

    Science.gov (United States)

    Costa, M C; Santos, E S; Barros, R J; Pires, C; Martins, M

    2009-05-01

    Possible use of wine wastes containing ethanol as carbon and energy source for sulphate-reducing bacteria (SRB) growth and activity in the treatment of acid mine drainage (AMD) is studied for the first time. The experiments were performed using anaerobic down-flow packed bed reactors in semi-continuous systems. The performance of two bioreactors fed with wine wastes or ethanol as carbon sources is compared in terms of sulphate reduction, metals removal and neutralization. The results show that efficient neutralization and high sulphate removal (>90%) were attained with the use of wine wastes as substrate allowing the production of effluents with concentrations below the required local legislation for irrigation waters. This is only possible provided that the AMD and wine wastes are contacted with calcite tailing, a waste material that neutralizes and provides buffer capacity to the medium. The removal of metals using wine wastes as carbon source was 61-91% for Fe and 97% for both Zn and Cu. The lower removal of iron, when wine waste is used instead of ethanol, may be due to the presence of iron-chelating compounds in the waste, which prevent the formation of iron sulphide, and partial unavailability of sulphide because of re-oxidation to elemental sulphur. However, that did not affect significantly the quality of the effluent for irrigation. This work demonstrates that wine wastes are a potential alternative to traditional SRB substrates. This finding has direct implication to sustainable operation of SRB bioreactors for AMD treatment. PMID:19201010

  10. [Nitrate removal from recirculating aquaculture system using polyhydroxybutyrate-co-hydroxyvalerate as carbon source ].

    Science.gov (United States)

    Zhang, Lanhe; Liu, Lili; Qiu, Tianlei; Gao, Min; Han, Meilin; Yuan, Ding; Wang, Xuming

    2014-09-01

    [ OBJECTIVE] Polyhydroxybutyrate-co-hydroxyvalerate (PHBV) was used as solid carbon source and biofilm carrier to remove nitrate from recirculating aquaculture system (RAS). Dynamics of microbial community structure in biofilm coating on carbon source packed into denitrification reactor were investigated. [METHODS] Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the microbial community in biofilm from denitrifiation reactor. Bacteria degrading PHBV were isolated from the reactor using pure culture method. [RESULTS] Nitrate decreased remarkably in the RAS connected with dentrification reactor. In contrast, Nitrate increased continuously in the conventional RAS without dentrification reactor. According to the phylogenetic analysis, the microbes in the biofilm samples from denitrification reactor were divided into Proteobacteria ( p-proteobacteria, γ-proteobacteria and δ- proteobacteria) , Firmicutes and Bacteroidetes. The major advantageous populations were Acidovorax and Bacillus in the 40-day reactor. The advantageous populations in the 150-day reactor were in order of Clostridium, Desulfitobacterium, Dechloromonas, Pseudoxanthomonas and Flavobacterium. Pure cultures of bacteria degrading PHBV isolated from denitrification reactor were classified into Acidovorax, Methylibium, Pseudoxanthomonas and Dechloromonas. [CONCLUSION] Nitrate could be removed effectively from RAS using PHBV as carbon source. Advantageous bacteria and their dynamic changes were ascertained in biofilm from denitrification reactor packed with PHBV. PMID:25522594

  11. Immunotoxic potential of aeration lagoon effluents for the treatment of domestic and hospital wastewaters in the freshwater mussel Elliptio complanata

    Institute of Scientific and Technical Information of China (English)

    Francois Gagné; Chantale André; Marlène Fortier; Michel Fournier

    2012-01-01

    Municipal wastewaters are major sources of pollution for the aquatic biota.The purpose of this study was to determine the levels of some pharmaceutical products and the immunotoxic potential of a municipal wastewater aeration lagoon for the treatment of the domestic wastewaters of a small town with wastewater inputs from a 400-bed hospital complex.Endemic mussels were collected,caged and placed in the final aeration lagoon and at sites 1 km upstream and 1 km downstream of the effluent outfall in the receiving river for a period of 14 days.The results showed that the final aeration lagoon contained high levels of total coliforms,conductivity and low dissolved oxygen (2.9 mg/L) as well as detectable amounts of trimethoprim,carbamazepine,gemfibrozil,and norfloxacin at concentrations exceeding 50 ng/L.The lagoon effluent was indeed toxic to the mussel specimens,as evidenced by the appearance of mortality after 14 days (10% mortality),decreased mussel weight-to-shell-length ratio and loss of hemocyte viability.The number of adhering hemocytes,phagocytic activity,total nitrite levels and arachidonic cyclooxygenase activity were significantly higher in mussels placed in the final aeration lagoon.A multivariate analysis also revealed that water pH,conductivity,total coliforms and dissolved oxygen were the endpoints most closely linked with phagocytic activity,the amount of adhering hemocytes and loss of hemocyte viability.In conclusion,exposure of mussels to treated aerated lagoon wastewater is deleterious to freshwater mussels where the immune system is compromised.

  12. Studies of radon mitigation in well water by aeration

    International Nuclear Information System (INIS)

    The 222Rn concentration in natural water in different countries usually is about few Bq/L and is the subject of the National legislation as well as International norms and recommendations. The United States Environmental Protection Agency (USEPA) established a limit of 11.1 Bq/L for the radon level in drinking water and this limit is considered as guideline in Canada and many countries of the European Union. This work presents the results of study of radon (222Rn) concentration reduction in well water using the aeration process developed at the Laboratory of Applied Nuclear Physics of the Federal University of Technology (UTFPR). The water samples were collected from a well at Pinheirinho region of Curitiba in 2011. Experimental setup was based on the Radon Monitor (AlphaGUARD). The 222Rn concentration was analyzed using the software DataEXPERT by Genitron Instruments, taking into account the volume of water sample, its temperature, atmospheric pressure and the total volume of the air in the vessels. Initial concentration of radon in water samples was 28,67 Bq/L which is bigger than maximum concentration recommended by USEPA. The mitigation was performed by means of diffusion aeration of water samples of 15L during the time interval of 24 hours following a period of 4 days. The efficiency of aeration mitigation was controlled by comparing the activity of radon in aerated water with reference water samples that were not aerated. Obtained results show very satisfactory decrease of 222Rn activity in water samples even after few hours of intense aeration. (author)

  13. Nitrogen removal from on-site treated anaerobic effluents using intermittently aerated moving bed biofilm reactors at low temperature.

    Science.gov (United States)

    Luostarinen, Sari; Luste, Sami; Valentín, Lara; Rintala, Jukka

    2006-05-01

    On-site post-treatment of anaerobically pre-treated dairy parlour wastewater (DPWWe; 10 degrees C) and mixture of kitchen waste and black water (BWKWe; 20 degrees C) was studied in moving bed biofilm reactors (MBBR). The focus was on removal of nitrogen and of residual chemical oxygen demand (COD). Moreover, the effect of intermittent aeration and continuous vs. sequencing batch operation was studied. All MBBRs removed 50-60% of nitrogen and 40-70% of total COD (CODt). Complete nitrification was achieved, but denitrification was restricted by lack of carbon. Nitrogen removal was achieved in a single reactor by applying intermittent aeration. Continuous and sequencing batch operation provided similar nitrogen and COD removal, wherefore simpler continuous feeding may be preferred for on-site applications. Combination of pre-treating upflow anaerobic sludge blanket (UASB) -septic tank and MBBR removed over 92% of CODt, 99% of biological oxygen demand (BOD7), and 65-70% of nitrogen. PMID:16647521

  14. Stable carbon isotope ratios of intact GDGTs indicate heterogeneous sources to marine sediments

    Science.gov (United States)

    Pearson, Ann; Hurley, Sarah J.; Walter, Sunita R. Shah; Kusch, Stephanie; Lichtin, Samantha; Zhang, Yi Ge

    2016-05-01

    Thaumarchaeota, the major sources of marine glycerol dibiphytanyl glycerol tetraether lipids (GDGTs), are believed to fix the majority of their carbon directly from dissolved inorganic carbon (DIC). The δ13C values of GDGTs (δ13CGDGT) may be powerful tools for reconstructing variations in the ocean carbon cycle, including paleoproductivity and water mass circulation, if they can be related to values of δ13CDIC. To date, isotope measurements primarily are made on the C40 biphytane skeletons of GDGTs, rather than on complete tetraether structures. This approach erases information revealed by the isotopic heterogeneity of GDGTs within a sample and may impart an isotopic fractionation associated with the ether cleavage. To circumvent these issues, we present δ13C values for GDGTs from twelve recent sediments representing ten continental margin locations. Samples are purified by orthogonal dimensions of HPLC, followed by measurement of δ13C values by Spooling Wire Microcombustion (SWiM)-isotope ratio mass spectrometry (IRMS) with 1σ precision and accuracy of ±0.25‰. Using this approach, we confirm that GDGTs, generally around -19‰, are isotopically "heavy" compared to other marine lipids. However, measured δ13CGDGT values are inconsistent with predicted values based on the 13C content of DIC in the overlying water column and the previously-published biosynthetic isotope fractionation for a pure culture of an autotrophic marine thaumarchaeon. In some sediments, the isotopic composition of individual GDGTs differs, indicating multiple source inputs. The data appear to confirm that crenarchaeol primarily is a biomarker for Thaumarchaeota, but its δ13C values still cannot be explained solely by autotrophic carbon fixation. Overall the complexity of the results suggests that both organic carbon assimilation (ca. 25% of total carbon) and multiple source(s) of exogenous GDGTs (contributing generally <30% of input to sediments) are necessary to explain the observed

  15. INVESTIGATION ON THE SPLASH LENGTH OF THE AERATED JET

    Institute of Scientific and Technical Information of China (English)

    Liu Shi-he; Qu Bo

    2003-01-01

    Atomized flow forms as an aerated jet from high dams impacts against the downstream water surface at high speed. Of all the regions of atomized flow the splash region is in the center of storm rainfall, which might cause certain damage to the hydropower stations and thence more attention should be paid. In this paper the impact of the water drop at the outer edge of the aerated jet against the downstream water surface was analyzed, and the motion of the splash water drop was investigated. Furthermore, a new formula for the calculation of the splash length was suggested, which is in good agreement with the data of model tests and prototype observation.

  16. Modelling and test of aeration tank settling (ATS)

    DEFF Research Database (Denmark)

    Nielsen, M. K.; Bechmann, H.; Henze, Mogens

    2000-01-01

    The use of aeration tank settling during high hydraulic loads on large wastewater treatment plants has previously been demonstrated as a reliable technique and proven valuable. The paper proposes a simplified deterministic model to predict the efficiency of the method. It is shown that a qualitat......The use of aeration tank settling during high hydraulic loads on large wastewater treatment plants has previously been demonstrated as a reliable technique and proven valuable. The paper proposes a simplified deterministic model to predict the efficiency of the method. It is shown that a...

  17. Hydrodynamic behaviour of the lateral flow biological aerated filter

    Institute of Scientific and Technical Information of China (English)

    HE Qiang; WANG Yin; FANG Jun-hua; ZHANG Hong-jing; XU Jing

    2006-01-01

    Pulsed signal experiment was carried out to determine the hydrodynamic behaviours of lateral flow biological aerated filter(LBAF). With the analysis of experimental results, LBAF is viewed as an approximate plug flow reactor, and hydraulic retention time distribution function was derived based on LBAF. The results show that flow rate and aeration strength are two critical factors which influence flow patterns in LBAF reactor. The hydrodynamic behaviour analysis of LBAF is the theoretical basis of future research on improving capacity factor and developing kinetic model for the reactor.

  18. AERATION EFFECT OF SUBMERGED JET ON HYDRAULIC CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A water-air two-phase turbulence mathematical model was proposed, The mass-weighted average was adoptedfor velocity, air mass fraction and turbulent parameters. Thealgebraic stress equation was used to calculate the Reynoldsstress. The pulsating flux of air mass fraction was simulatedby employing the concept of the eddy viscosity. The numericalsimulation of aerated flow in plunge pool shows that, for the same depth, aeration may decrease the time-averaged pressureon pool floor and increase slightly the turbulent intensity. Thecomputed concentration and pressure distributions coincidewith the experimental data.

  19. Characteristics of integrated biological aerated filter in municipal wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    HE Qiang; ZHANG Yu-ping; XU Jian-bin

    2005-01-01

    In this paper, the characteristics of integrated biological aerated filter (IBAF) applied to municipal wastewater treatment were studied in a pilot scale experiment. The experimental results showed that IBAF has high efficiencies in removing organic pollutants, such as CODCr and SS, in municipal wastewater. The removal rates of CODCr and SS can reach over 90% and 80%, respectively, when COD and SS in the influent are 234 mg L-1 and 112 mg L-1, hydraulic retention time (HRT) is 8 h, and the aerated intensity is in the range of (0.5 to 0.6) L m-2 s-1.

  20. Case study of aeration performance under changing process conditions

    DEFF Research Database (Denmark)

    Iranpour, R.; Shao, Y.J.; Ahring, Birgitte Kiær;

    2002-01-01

    Off gas analyses of oxygen transfer efficiency (OTE) at Terminal Island Treatment Plant of Los Angeles document changing performance of fine-pore diffusers in an activated sludge plant from 1991 to 1998. Although the plant treats a challenging waste stream, the aeration tanks are little different...... from other plants. Recent sessions provided improved time and space resolution, compared to previous work. Samples were more closely spaced, and some samples were taken in the intervals between the aeration grids, at the ends of the tanks, and near the edges of the grids. Very short term fluctuations...

  1. Effect of media heights on the performance of biological aerated filter

    Institute of Scientific and Technical Information of China (English)

    HU Yong-you; WANG Li-li

    2005-01-01

    The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes of organic carbon contents and ammonia concentration at different media height was got. The results showed that as a down flow BAF with granular media, the active layer of nitrifiers was deeper than heterotrophs in BAF. And the optimum media height for the removal of SS, CODCr and NH4+ -N was 40 cm,60 cm and 80 cm respectively. The removal efficiency of SS, CODCr and NH4+-N was 79.1%, 63.9% and 96.4% respectively under the influent CODCr and NH4+ -N of 122.1 mgCODCr/L and 14.84 mgNH4+ -N/L, the influent flux of 15.8 L/h, air to liquid ratio of 3: 1.

  2. Total organic carbon, an important tool in a holistic approach to hydrocarbon source fingerprinting

    International Nuclear Information System (INIS)

    Total organic carbon (TOC) was used to verify the consistency of source allocation results for the natural petrogenic hydrocarbon background of the northern Gulf of Alaska and Prince William Sound where the Exxon Valdez oil spill occurred in 1998. The samples used in the study were either pre-spill sediments or from the seafloor outside the spill path. It is assumed that the natural petrogenic hydrocarbon background in the area comes from either seep oil residues and shale erosion including erosion from petroleum source rock shales, or from coals including those of the Bering River coalfields. The objective of this study was to use the TOC calculations to discriminate between the two very different sources. TOC can constrain the contributions of specific sources and rule out incorrect source allocations, particularly when inputs are dominated by fossil organic carbon. The benthic sediments used in this study showed excellent agreement between measured TOC and calculated TOC from hydrocarbon fingerprint matches of polycyclic aromatic hydrocarbons (PAH) and chemical biomarkers. TOC and fingerprint matches confirmed that TOC sources were properly identified. The matches quantify the hydrocarbon contributions of different sources to the benthic sediments and the degree of hydrocarbon winnowing by waves and currents. It was concluded that the natural petrogenic hydrocarbon background in the sediments in the area comes from eroding Tertiary shales and oil seeps along the northern Gulf of Alaska coast. Thermally mature area coals are excluded from being important contributors to the background at Prince William Sound because of their high TOC content. 26 refs., 4 figs

  3. Relation between Shunt, Aeration, and Perfusion in Experimental Acute Lung Injury

    OpenAIRE

    Musch, Guido; Bellani, Giacomo; Vidal Melo, Marcos F; Harris, R. Scott; Winkler, Tilo; Schroeder, Tobias; Venegas, Jose G

    2007-01-01

    Rationale: In a pulmonary process characterized by spatially heterogeneous loss of aeration, the impairment of gas exchange is expected to depend on the regional distribution of perfusion relative to that of aeration.

  4. In-tank aeration, a necessary compliment of loaded systems in an airlift recirculating aquaculture system

    Science.gov (United States)

    Water treatment components in recirculating aquaculture systems in generally address solids removal, nitrification, circulation, aeration, and degasification. Airlift pumps in a recirculating aquaculture system can address water circulation, aeration, and degasification. Recent data indicates oxygen...

  5. Production of extracellular ferulic acid esterases by Lactobacillus strains using natural and synthetic carbon sources

    Directory of Open Access Journals (Sweden)

    Dominik Szwajgier

    2011-09-01

    Full Text Available Background. Ferulic acid esterases (FAE, EC 3.1.1.73, also known as feruloyl esterases, cinnamic acid esterases or cinnamoyl esterases, belong to a common group of hydrolases distributed in the plant kingdom. Especially the fungal enzymes were very well characterised in the past whereas the enzyme was rarely found in the lactic acid bacteria (LAB strains. It is well known that strong antioxidants free phenolic acids can be released from the dietary fiber by the action of intestinal microflora composed among others also of Lactobacillus strains. The aim of this study was to examine four Lactobacillus strains (L. acidophilus K1, L. rhamnosus E/N, PEN, OXYfor the ability to produce extracellular FAE on different synthetic and natural carbon sources. Material and methods. The LAB strains were grown in the minimal growth media using German wheat bran, rye bran, brewers’ spent grain, isolated larchwood arabinogalactan, apple pectin, corn pectin, methyl ferulate, methyl p-coumarate, methyl syringate or methyl vanillate as the sole carbon source. FAE activity was determined using the post-cultivation supernatants, methyl ferulate and HPLC with UV detection. Results. The highest FAE activity was obtained with L. acidophilus K1 and methyl ferulate (max. 23.34 ±0.05 activity units and methyl p-coumarate (max. 14.96 ±0.47 activity units as carbon sources. L. rhamnosus E/N, OXY and PEN exhibited the limited ability to produce FAE with cinnamic acids methyl esters. Methyl syringate and methyl vanillate (MS and MV were insufficient carbon sources for FAE production. Brewers’ spent grain was the most suitable substrate for FAE production by L. acidophilus K1 (max. 2.64 ±0.06 activity units and L. rhamnosus E/N, OXY and PEN. FAE was also successfully induced by natural substrates rye bran, corn pectin (L. acidophilus K1, German wheat bran and larchwood arabinogalactan (E/N, PEN or German wheat bran and corn pectin (OXY. Conclusions. This study proved the

  6. Sequential Aeration of Membrane-Aerated Biofilm Reactors for High-Rate Autotrophic Nitrogen Removal: Experimental Demonstration

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Sun, Sheng-Peng; Lackner, Susanne;

    2010-01-01

    One-stage autotrophic nitrogen (N) removal, requiring the simultaneous activity of aerobic and anaerobic ammonium oxidizing bacteria (AOB and AnAOB), can be obtained in spatially redox-stratified biofilms. However, previous experience with Membrane-Aerated Biofilm Reactors (MABRs) has revealed a...... difficulty in reducing the abundance and activity of nitrite oxidizing bacteria (NOB), which drastically lowers process efficiency. Here we show how sequential aeration is an effective strategy to attain autotrophic N removal in MABRs: Two separate MABRs, which displayed limited or no N removal under......S rRNA gene confirmed that sequential aeration, even at elevated average O2 loads, stimulated the abundance of AnAOB and AOB and prevented the increase in NOB. Nitrous oxide (N2O) emissions were 100-fold lower compared to other anaerobic ammonium oxidation (Anammox)-nitritation systems. Hence, by...

  7. Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya

    Directory of Open Access Journals (Sweden)

    S. Bouillon

    2004-01-01

    Full Text Available The origin of carbon substrates used by in situ sedimentary bacterial communities was investigated in an intertidal mangrove ecosystem and in adjacent seagrass beds in Gazi bay (Kenya by δ13C analysis of bacteria-specific PLFA (phospholipid fatty acids and bulk organic carbon. Export of mangrove-derived organic matter to the adjacent seagrass-covered bay was evident from sedimentary total organic carbon (TOC and δ13CTOC data. PLFA δ13C data indicate that the substrate used by bacterial communities varied strongly and that exported mangrove carbon was a significant source for bacteria in the adjacent seagrass beds. Within the intertidal mangrove forest, bacterial PLFA at the surface layer (0-1cm typically showed more enriched δ13C values than deeper (up to 10cm sediment layers, suggesting a contribution from microphytobenthos and/or inwelled seagrass material. Under the simplifying assumption that seagrasses and mangroves are the dominant potential end-members, the estimated contribution of mangrove-derived carbon to benthic mineralization in the seagrass beds (16-74% corresponds fairly well to the estimated contribution of mangrove C to the sedimentary organic matter pool (21-71% across different seagrass sites. Based on the results of this study and a compilation of literature data, we suggest that trapping of allochtonous C is a common feature in seagrass beds and often represents a significant source of C for sediment bacteria - both in cases where seagrass C dominates the sediment TOC pool and in cases where external inputs are significant. Hence, it is likely that data on community respiration rates systematically overestimate the role of in situ mineralization as a fate of seagrass production.

  8. Carbon Sources and Sinks in Freshwater and Estuarine Environments of the Arctic Coastal Plain.

    Science.gov (United States)

    Lougheed, V.; Tarin, G.; Tweedie, C. E.

    2015-12-01

    The source, fate and transport of terrestrially derived carbon as it moves through multiple landscape components (i.e. groundwater, rivers, ponds, wetlands, lakes, lagoons) on a path from land to sea in permafrost-dominated watersheds is poorly understood. Critical to our understanding of Arctic carbon budgets are small, but numerically abundant watersheds that dominate the landscape of the Alaskan Arctic Coastal Plain (ACP), which appears to be changing rapidly in response to climate warming and other environmental changes. This study was designed to understand the contribution of freshwater ecosystems in the Arctic to regional carbon budgets. pCO2 was logged continually in ponds, lakes and streams sites near Barrow, AK and recorded across transects in Elson Lagoon, a coastal lagoon on the Beaufort coast. Average pCO2 of the pond over 2 weeks in August (1196 μatm) was double that of lakes and streams, and four times higher than Elson Lagoon (216 μatm); thus, the Lagoon was acting as a small sink while the pond was a substantial source of CO2 to the atmosphere. The uptake of CO2 in Elson Lagoon, combined with an oversaturation of O2, may be due to enhanced primary productivity caused by freshwater nutrient inputs. Conversely, pCO2, chlorophyll-a and DOC increased substantially in the pond after a large rain event, suggesting that run-off introduced large amounts of terrestrially-derived carbon from groundwater. Further studies are required to elucidate the fate and transport of carbon in the numerically abundant smaller watersheds of the Arctic.

  9. Mass absorption efficiency of elemental carbon for source samples from residential biomass and coal combustions

    Science.gov (United States)

    Shen, Guofeng; Chen, Yuanchen; Wei, Siye; Fu, Xiaofang; Zhu, Ying; Tao, Shu

    2013-11-01

    Optical properties of particulate matter are of growing concern due to their complex effects on atmospheric visibility and local/regional climate change. In this study, mass absorption efficiency (MAE) of elemental carbon (EC) was measured for source emission samples obtained from the residential combustions of solid fuels using a thermal-optical carbon analyzer. For source samples from residential wood, crop straw, biomass pellet and coal combustions, MAE of EC measured at 650 nm, were 3.1 (2.4-3.7 as 95% Confidence Interval), 6.6 (5.5-7.6), 9.5 (6.7-12), and 7.9 (4.8-11) m2 g-1, respectively. MAE of EC for source sample from the wood combustion was significantly lower than those for the other fuels, and MAE of EC for coal briquette appeared to be different from that of raw chunk. MAE values of the investigated source emission samples were found to correlate with OC/EC ratio, and a significantly positive correlation was found between MAE and particle-bound polycyclic aromatic hydrocarbons (pPAHs), though pPAHs contributed a relatively small fraction of OC.

  10. Development of C{sup 6+} laser ion source and RFQ linac for carbon ion radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sako, T., E-mail: takayuki1.sako@toshiba.co.jp; Yamaguchi, A.; Sato, K. [Toshiba Corporation, Yokohama 235-8522 (Japan); Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T. [Cancer Research Center, Yamagata University Faculty of Medicine, Yamagata 990-9585 (Japan); Takeuchi, T. [Accelerator Engineering Corporation, Chiba 263-0043 (Japan)

    2016-02-15

    A prototype C{sup 6+} injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

  11. Development of C6+ laser ion source and RFQ linac for carbon ion radiotherapy

    Science.gov (United States)

    Sako, T.; Yamaguchi, A.; Sato, K.; Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T.; Takeuchi, T.

    2016-02-01

    A prototype C6+ injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

  12. Development of C⁶⁺ laser ion source and RFQ linac for carbon ion radiotherapy.

    Science.gov (United States)

    Sako, T; Yamaguchi, A; Sato, K; Goto, A; Iwai, T; Nayuki, T; Nemoto, K; Kayama, T; Takeuchi, T

    2016-02-01

    A prototype C(6+) injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4. PMID:26932119

  13. Synthesis of CNTs via chemical vapor deposition of carbon dioxide as a carbon source in the presence of NiMgO

    International Nuclear Information System (INIS)

    Carbon nanotubes were synthesized via the chemical vapor deposition (CVD) method, using Ni/MgO as a catalyst and CO2 as a nontoxic, abundant, and economical carbon source. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM), along with the results from Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy, confirmed the successful formation of CNTs. Energy-dispersive X-ray spectroscopy (EDX) was performed to investigate the weight percentage of the present elements in the synthesized powder, and a significant yield of 27.38% was confirmed. The reaction mechanism was discussed, and the role of the carbon source, catalyst support, and presence of H2 in the reaction environment was elaborated. - Highlights: • CO2 was used as a nontoxic and economical carbon source for CNT production. • A novel Ni supported MgO has been synthesized and employed in the CVD process. • CNTs were produced with a significant yield of 27.38%

  14. Quantifying Contemporary Terrestrial Carbon Sources and Sinks in the Conterminous United States

    Science.gov (United States)

    Liu, S.; Loveland, T.

    2003-12-01

    U.S. land likely accounts for a significant portion of the unidentified global carbon sink, although the magnitude is highly uncertain. The ultimate goal of this study is to quantify the contemporary temporal and spatial patterns of carbon sources and sinks in the conterminous United States from the early 1970s to 2000, and to explain the mechanisms that cause the variability and changes. Because of the difficulty and massive cost for developing land cover change databases for the conterminous United States, we adopt an ecoregion-based sampling approach. Carbon dynamics within thousands of 20 km by 20 km or 10 km by 10 km sampling blocks, stratified by Omernik Level III ecoregions, are simulated using the General Ensemble Biogeochemical Modeling System at the spatial resolution of 60 m by 60 m. The land use change data, providing unprecedented accuracy and consistency, are derived from Landsat imagery for five time points (nominally 1972, 1980, 1986, 1992, and 2000). Mechanisms have been implemented to assimilate data from key national benchmark databases (including the USDA Forest Service­_s Forest Inventory and Analysis data and the USDA­_s agricultural census data). The dynamics of carbon stocks in vegetation, soil, and harvested wood materials are quantified. Results from three ecoregions (i.e., Southeastern Plains, Piedmont, and Northern Piedmont) indicated that the carbon sink strength has been decreasing from the 1970s to 2000. The relative contribution of biomass accumulation to the sink decreased during this period, while those of soil organic carbon and harvested wood materials increased.

  15. Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya

    Directory of Open Access Journals (Sweden)

    F. Dehairs

    2004-08-01

    Full Text Available The origin of carbon substrates used by in situ sedimentary bacterial communities was investigated in an intertidal mangrove ecosystem and in adjacent seagrass beds in Gazi bay (Kenya by δ13C analysis of bacteria-specific PLFA (phospholipid fatty acids and bulk organic carbon. Export of mangrove-derived organic matter to the adjacent seagrass-covered bay was evident from sedimentary total organic carbon (TOC and δ13CTOC data. PLFA δ13C data indicate that the substrate used by bacterial communities varied strongly and that exported mangrove carbon was a significant source for bacteria in the adjacent seagrass beds. Within the intertidal mangrove forest, bacterial PLFA at the surface layer (0-1 cm typically showed more enriched δ13C values than deeper (up to 10 cm sediment layers, suggesting a contribution from microphytobenthos and/or inwelled seagrass material. Under the assumption that seagrasses and mangroves are the dominant potential end-members, the estimated contribution of mangrove-derived carbon to benthic mineralization in the seagrass beds (16-74% corresponds fairly well to the estimated contribution of mangrove C to the sedimentary organic matter pool (21-71% across different seagrass sites. Based on these results and a compilation of literature data, we suggest that allochtonous carbon trapped in seagrass beds may often represent a significant fraction of the substrate for benthic mineralization - both in cases where seagrass C dominates the sediment TOC pool and in cases where external inputs are significant. Hence, it is likely that community respiration data systematically overestimate the role of mineralization in the overall seagrass C budget.

  16. Fossil and Nonfossil Sources of Organic and Elemental Carbon Aerosols in the Outflow from Northeast China.

    Science.gov (United States)

    Zhang, Yan-Lin; Kawamura, Kimitaka; Agrios, Konstantinos; Lee, Meehye; Salazar, Gary; Szidat, Sönke

    2016-06-21

    Source quantification of carbonaceous aerosols in the Chinese outflow regions still remains uncertain despite their high mass concentrations. Here, we unambiguously quantified fossil and nonfossil contributions to elemental carbon (EC) and organic carbon (OC) of total suspended particles (TSP) from a regional receptor site in the outflow of Northeast China using radiocarbon measurement. OC and EC concentrations were lower in summer, representing mainly marine air, than in other seasons, when air masses mostly traveled over continental regions in Mongolia and northeast China. The annual-mean contribution from fossil-fuel combustion to EC was 76 ± 11% (0.1-1.3 μg m(-3)). The remaining 24 ± 11% (0.03-0.42 μg m(-3)) was attributed to biomass burning, with slightly higher contribution in the cold period (∼31%) compared to the warm period (∼21%) because of enhanced emissions from regional biomass combustion sources in China. OC was generally dominated by nonfossil sources, with an annual average of 66 ± 11% (0.5-2.8 μg m(-3)), approximately half of which was apportioned to primary biomass-burning sources (34 ± 6%). In winter, OC almost equally originated from primary OC (POC) emissions and secondary OC (SOC) formation from fossil fuel and biomass-burning sources. In contrast, summertime OC was dominated by primary biogenic emissions as well as secondary production from biogenic and biomass-burning sources, but fossil-derived SOC was the smallest contributor. Distinction of POC and SOC was performed using primary POC-to-EC emission ratios separated for fossil and nonfossil emissions. PMID:27203471

  17. Molasses as an efficient low-cost carbon source for biological Cr(VI) removal

    Energy Technology Data Exchange (ETDEWEB)

    Michailides, Michail K. [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Tekerlekopoulou, Athanasia G., E-mail: atekerle@upatras.gr [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Akratos, Christos S.; Coles, Sandra [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Pavlou, Stavros [Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou Str., Platani, P.O. Box 1414, GR-26504 Patras (Greece); Department of Chemical Engineering, University of Patras, GR-26504 Patras (Greece); Vayenas, Dimitrios V. [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou Str., Platani, P.O. Box 1414, GR-26504 Patras (Greece)

    2015-01-08

    Highlights: • Suspended and attached growth reactors were examined for Cr(VI) bio-reduction. • Molasses was proved an efficient and very low cost carbon source. • Molasses was more efficient than sugar in enhancing Cr(VI) reduction. • SBR with recirculation was the most proper operating mode. - Abstract: In the present study, indigenous microorganisms from industrial sludge were used to reduce the activity of Cr(VI). Molasses, a by-product of sugar processing, was selected as the carbon source (instead of sugar used in a previous work) as it is a low-cost energy source for bioprocesses. Initially, experiments were carried out in suspended growth batch reactors for Cr(VI) concentrations of 1.5–110 mg/L. The time required for complete Cr(VI) reduction increased with initial Cr(VI) concentration. Initial molasses concentration was also found to influence the Cr(VI) reduction rate. The optimal concentration for all initial Cr(VI) concentrations tested was 0.8 gC/L. Experiments were also carried out in packed-bed reactors. Three different operating modes were used to investigate the optimal performance and efficiency of the filter, i.e. batch, continuous and SBR with recirculation. The latter mode with a recirculation rate of 0.5 L/min lead to significantly high Cr(VI) reduction rates (up to 135 g/m{sup 2} d). The results of this work were compared with those of a similar work using sugar as the carbon source and indicate that molasses could prove a feasible technological solution to a serious environmental problem.

  18. Molasses as an efficient low-cost carbon source for biological Cr(VI) removal

    International Nuclear Information System (INIS)

    Highlights: • Suspended and attached growth reactors were examined for Cr(VI) bio-reduction. • Molasses was proved an efficient and very low cost carbon source. • Molasses was more efficient than sugar in enhancing Cr(VI) reduction. • SBR with recirculation was the most proper operating mode. - Abstract: In the present study, indigenous microorganisms from industrial sludge were used to reduce the activity of Cr(VI). Molasses, a by-product of sugar processing, was selected as the carbon source (instead of sugar used in a previous work) as it is a low-cost energy source for bioprocesses. Initially, experiments were carried out in suspended growth batch reactors for Cr(VI) concentrations of 1.5–110 mg/L. The time required for complete Cr(VI) reduction increased with initial Cr(VI) concentration. Initial molasses concentration was also found to influence the Cr(VI) reduction rate. The optimal concentration for all initial Cr(VI) concentrations tested was 0.8 gC/L. Experiments were also carried out in packed-bed reactors. Three different operating modes were used to investigate the optimal performance and efficiency of the filter, i.e. batch, continuous and SBR with recirculation. The latter mode with a recirculation rate of 0.5 L/min lead to significantly high Cr(VI) reduction rates (up to 135 g/m2 d). The results of this work were compared with those of a similar work using sugar as the carbon source and indicate that molasses could prove a feasible technological solution to a serious environmental problem

  19. Preparation and Physicochemical Evaluation of Controlled-release Carbon Source Tablet for Groundwater in situ Denitrification

    Science.gov (United States)

    Kim, Y.; Kang, J. H.; Yeum, Y.; Han, K. J.; Kim, D. W.; Park, C. W.

    2015-12-01

    Nitric nitrogen could be the one of typical pollution source such asNO3-through domestic sewage, livestock and agricultural wastewater. Resident microflorain aquifer has known to remove the nitric nitrogen spontaneously following the denitration process with the carbon source (CS) as reactant. However, it could be reacted very slowly with the rack of CS and there have been some studies for controlled addition of CS (Ref #1-3). The aim of this study was to prepare the controlled-release carbon source (CR-CS) tablet and to evaluate in vitro release profile for groundwater in situ denitrification. CR-CS tablet could be manufactured by direct compression method using hydraulic laboratory press (Caver® 3850) with 8 mm rounded concave punch/ die.Seven kinds of CR-CS tablet were prepared to determine the nature of the additives and their ratio such as sodium silicate, dicalcium phosphate, bentonite and sand#8.For each formulation, the LOD% and flowability of pre-mixed powders and the hardness of compressed tablets were analyzed. In vitro release study was performed to confirm the dissolution profiles following the USP Apparatus 2 method with Distilled water of 900mL, 20 °C. As a result, for each lubricated powders, they were compared in terms of ability to give an acceptable dry pre-mixed powder for tableting process. The hardness of the compressed tablets is acceptable whatever the formulations tested. After in vitro release study, it could confirm that the different formulations of CR-CS tablet have a various release rate patterns, which could release 100% at 3 hrs, 6 hrs and 12 hrs. The in vitro dissolution profiles were in good correlation of Higuchi release kinetic model. In conclusion, this study could be used as a background for development and evaluation of the controlled-release carbon source (CR-CS) tablet for the purification of groundwater following the in situ denitrification.

  20. Development and evaluation of a new aerator for the catfish industry

    Science.gov (United States)

    Traditional paddle-wheel aerators have been used for supplemental and emergency aeration in the aquaculture industry for over 30 years but distribute a high volume of water which dilutes the aeration effort over the entire pond volume. Thus, a great deal of equipment and a large amount of power is r...

  1. Influence of aeration degree of cultural liquid on biosintetical activity of fungus culture Blakeslea trispora

    OpenAIRE

    A. S. Anatsky; Y. A. Kunshchikova

    2009-01-01

    Β-carotene biosynthetic processes of the fungus Blakeslea trispora are studied for different technological modes of cultural liquid aeration under industrial conditions. It is shown, that the increase of aeration degree stimulates the accumulation of biomass and carotene’s formation. The operating practices of the maximal aeration since the 10th hour of cultivation are recommended to the use.

  2. Effect of pond aeration on growth and survival of Penaeus monodon Fab.

    OpenAIRE

    R. K. Mohanty

    2001-01-01

    The effect of paddle wheel aeration on shrimp growth and survival were studied at a commercial farm at Chandipur coast of Orissa, India, at different stocking densities of Penaeus monodon. Four different aeration patterns were adopted and evaluated. Influence of individual aeration pattern on average survival rate was not highly significant (p

  3. Intermittent aeration to improve wastewater treatment efficiency in pilot-scale constructed wetland.

    Science.gov (United States)

    Uggetti, Enrica; Hughes-Riley, Theodore; Morris, Robert H; Newton, Michael I; Trabi, Christophe L; Hawes, Patrick; Puigagut, Jaume; García, Joan

    2016-07-15

    Forced aeration of horizontal subsurface flow constructed wetlands (HSSF CWs) is nowadays a recognized method to improve treatment efficiency, mainly in terms of ammonium removal. While numerous investigations have been reported testing constant aeration, scarce information can be found about the efficiency of intermittent aeration. This study aims at comparing continuous and intermittent aeration, establishing if there is an optimal regime that will increase treatment efficiency of HSSF CWs whilst minimizing the energy requirement. Full and intermittent aeration were tested in a pilot plant of three HSSF CWs (2.64m(2) each) fed with primary treated wastewater. One unit was fully aerated; one intermittently aerated (i.e. by setting a limit of 0.5mg/L dissolved oxygen within the bed) with the remaining unit not aerated as a control. Results indicated that intermittent aeration was the most successful operating method. Indeed, the coexistence of aerobic and anoxic conditions promoted by the intermittent aeration resulted in the highest COD (66%), ammonium (99%) and total nitrogen (79%) removals. On the other hand, continuous aeration promotes ammonium removal (99%), but resulted in nitrate concentrations in the effluent of up to 27mg/L. This study demonstrates the high potential of the intermittent aeration to increase wastewater treatment efficiency of CWs providing an extreme benefit in terms of the energy consumption. PMID:27062558

  4. Directional Flow of Summer Aeration to Manage Insect Pests in Stored Wheat

    Science.gov (United States)

    Field trials were conducted in metal wheat storage bins to determine whether pressure aeration, pushing ambient air from the bottom, or suction aeration, pulling air down from the top, would be more efficient at cooling the wheat mass and thereby limiting insect population growth. Aeration was accom...

  5. 7 CFR 201.55a - Moisture and aeration of substratum.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Moisture and aeration of substratum. 201.55a Section... and aeration of substratum. (a) The substratum must be moist enough to supply the needed moisture to the seeds at all times. Excessive moisture which will restrict aeration of the seeds should be...

  6. Sources of black carbon to the Himalayan–Tibetan Plateau glaciers

    Science.gov (United States)

    Li, Chaoliu; Bosch, Carme; Kang, Shichang; Andersson, August; Chen, Pengfei; Zhang, Qianggong; Cong, Zhiyuan; Chen, Bing; Qin, Dahe; Gustafsson, Örjan

    2016-01-01

    Combustion-derived black carbon (BC) aerosols accelerate glacier melting in the Himalayas and in Tibet (the Third Pole (TP)), thereby limiting the sustainable freshwater supplies for billions of people. However, the sources of BC reaching the TP remain uncertain, hindering both process understanding and efficient mitigation. Here we present the source-diagnostic Δ14C/δ13C compositions of BC isolated from aerosol and snowpit samples in the TP. For the Himalayas, we found equal contributions from fossil fuel (46±11%) and biomass (54±11%) combustion, consistent with BC source fingerprints from the Indo-Gangetic Plain, whereas BC in the remote northern TP predominantly derives from fossil fuel combustion (66±16%), consistent with Chinese sources. The fossil fuel contributions to BC in the snowpits of the inner TP are lower (30±10%), implying contributions from internal Tibetan sources (for example, yak dung combustion). Constraints on BC sources facilitate improved modelling of climatic patterns, hydrological effects and provide guidance for effective mitigation actions. PMID:27552223

  7. Sources of black carbon to the Himalayan-Tibetan Plateau glaciers.

    Science.gov (United States)

    Li, Chaoliu; Bosch, Carme; Kang, Shichang; Andersson, August; Chen, Pengfei; Zhang, Qianggong; Cong, Zhiyuan; Chen, Bing; Qin, Dahe; Gustafsson, Örjan

    2016-01-01

    Combustion-derived black carbon (BC) aerosols accelerate glacier melting in the Himalayas and in Tibet (the Third Pole (TP)), thereby limiting the sustainable freshwater supplies for billions of people. However, the sources of BC reaching the TP remain uncertain, hindering both process understanding and efficient mitigation. Here we present the source-diagnostic Δ(14)C/δ(13)C compositions of BC isolated from aerosol and snowpit samples in the TP. For the Himalayas, we found equal contributions from fossil fuel (46±11%) and biomass (54±11%) combustion, consistent with BC source fingerprints from the Indo-Gangetic Plain, whereas BC in the remote northern TP predominantly derives from fossil fuel combustion (66±16%), consistent with Chinese sources. The fossil fuel contributions to BC in the snowpits of the inner TP are lower (30±10%), implying contributions from internal Tibetan sources (for example, yak dung combustion). Constraints on BC sources facilitate improved modelling of climatic patterns, hydrological effects and provide guidance for effective mitigation actions. PMID:27552223

  8. Global warming alters carbon sink and source situation of the Tibetan lakes

    Science.gov (United States)

    Jiang, H.; Ni, Q.; Yang, J.; Liu, W.

    2015-12-01

    Global warming would accelerate glacier retreat and permafrost degeneration on the Tibetan Plateau. The carbon stored in permafrost would be released to nearby lakes. However, little is known about how the carbon sink and source situation could be altered and what role the microbial community could play in Tibetan lakes in response to global warming. To fill this knowledge gap, six lakes (Erhai Lake, Qinghai Lake, Tuosu Lake, Gahai Lake, Xiaochaidan Lake and Lake Chaka) on the Tibetan Plateau were studied. In order to compare the seasonal variations in geochemistry and microbial communities, two sampling cruises were performed (May and July of 2015, corresponding to dry and wet seasons, respectively). For each lake, salinity, pH, dissolved organic carbon (DOC), total nitrogen (TN), and chlorophyll were measured for water samples, and salinity and total organic carbon (TOC) were measured for sediments. Chamber-based greenhouse gas flux measurement were performed on the surface of each lake. Microbial communities were analyzed by using MiSeq sequencing technique. The results showed that in response to seasonal variation (from dry to set season), lake surface increased by 5-20% (calculated on the basis of satellite data) and salinity decreased by 4-30% for the studied lakes, suggesting the studied lakes were diluted by precipitations. The DOC contents of the lake waters were almost stable for the studied lakes, whereas TN increased by more than 70% for the lakes with salinity less than 100g/L. In the meanwhile, chlorophyll content increased by more than 180% for lakes with low salinities (Erhai Lake, Qinghai Lake, and Tuosu Lake) and decreased by 17-94% for lakes with high salinities (Gahai Lake, Xiaoxhaidan Lake, and Lake Chaka. This indicated that desalination (precipitation plus glacier melt) would increase carbon fixation potential in Tibetan lakes. Microbial community analyses showed that microbial diversity increased in response to desalination. All in all

  9. Seasonal variability of organic matter composition in an Alaskan glacier outflow: insights into glacier carbon sources

    International Nuclear Information System (INIS)

    Glacier ecosystems are a significant source of bioavailable, yet ancient dissolved organic carbon (DOC). Characterizing DOC in Mendenhall Glacier outflow (southeast Alaska) we document a seasonal persistence to the radiocarbon-depleted signature of DOC, highlighting ancient DOC as a ubiquitous feature of glacier outflow. We observed no systematic depletion in Δ 14C-DOC with increasing discharge during the melt season that would suggest mobilization of an aged subglacial carbon store. However, DOC concentration, δ 13C-DOC, Δ 14C-DOC and fluorescence signatures appear to have been influenced by runoff from vegetated hillslopes above the glacier during onset and senescence of melt. In the peak glacier melt period, the Δ 14C-DOC of stream samples at the outflow (−181.7 to −355.3‰) was comparable to the Δ 14C-DOC for snow samples from the accumulation zone (−207.2 to −390.9‰), suggesting that ancient DOC from the glacier surface is exported in glacier runoff. The pre-aged DOC in glacier snow and runoff is consistent with contributions from fossil fuel combustion sources similar to those documented previously in ice cores and thus provides evidence for anthropogenic perturbation of the carbon cycle. Overall, our results emphasize the need to further characterize DOC inputs to glacier ecosystems, particularly in light of predicted changes in glacier mass and runoff in the coming century. (papers)

  10. INCOME AND ENERGY SOURCES AMONG AGRARIAN HOUSEHOLDS IN NIGERIA: IMPLICATIONS FOR LOW CARBON ENERGY DEVELOPMENT IN LESS DEVELOPED COUNTRIES

    Directory of Open Access Journals (Sweden)

    M. Mkpado

    2012-07-01

    Full Text Available Low-carbon power comes from sources that produce fewer greenhouse gases than do traditional means of power generation. It includes zero carbon power generation sources, such as wind power, solar power, geothermal power and (except for fuel preparation nuclear power, as well as sources with lower-level emissions such as natural and petroleum gas, and also technologies that prevent carbon dioxide from being emitted into the atmosphere, such as carbon capture and storage. This article correlated value of income from different sources to energy sources used by agrarian households in Nigeria and drew implications for low carbon development in Africa. It analysis included use of wind power for irrigation purposes, harnessing solar energy for lightening and possible cost implications. Secondary data were collected from Community Based Monitoring System Nigeria Project. Descriptive statistics, correlation and qualitative analysis were employed. The average annual income of agrarian households from different sources such as crop farming, livestock farming, petty trading, forest exploitation, remittance and labour per day was below the poverty line of $1 per day. The source of energy that had the highest number of significant correlation was electrical energy (low carbon electrical energy. It showed the possibility of pooling resources as farmers group to attract grants or equity financing to build wind mills for irrigation. The study recommended use of energy efficient bulbs to reduce CO2 emissions. This requires creating awareness among rural dwellers of the need to make such change.

  11. Preliminary study on preparation of BCNO phosphor particles using citric acid as carbon source

    Energy Technology Data Exchange (ETDEWEB)

    Nuryadin, Bebeh W.; Pratiwi, Tripuspita; Faryuni, Irfana D.; Iskandar, Ferry, E-mail: ferry@fi.itb.ac.id; Abdullah, Mikrajuddin; Khairurrijal [Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Ganesha 10 Bandung, Indonesia 40132 (Indonesia); Ogi, Takashi; Okuyama, Kikuo [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima, Japan 739-8527 (Japan)

    2015-04-16

    A citric acid was used as a carbon source in the preparation of boron carbon oxy-nitride (BCNO) phosphor particles by a facile process. The preparation process was conducted at relatively low temperature 750 °C and at ambient pressure. The prepared BCNO phosphors showed a high photoluminescence (PL) performance at peak emission wavelength of 470 nm under excitation by a UV light 365 nm. The effects of carbon/boron and nitrogen/boron molar ratios on the PL properties were also investigated. The result showed that the emission spectra with a wavelength peak ranging from 444 nm to 496 nm can be obtained by varying carbon/boron ratios from 0.1 to 0.9. In addition, the observations showed that the BCNO phosphor material has two excitation peaks located at the 365 nm (UV) and 420 nm (blue). Based on these observations, we believe that the citric acid derived BCNO phosphor particles can be a promising inexpensive material for phosphor conversion-based white LED.

  12. Contribution of various carbon sources toward isoprene synthesis mediated by altered atmospheric CO2 concentrations

    Science.gov (United States)

    Trowbridge, A. M.; Asensio, D.; Eller, A. S.; Wilkinson, M. J.; Schnitzler, J.; Jackson, R. B.; Monson, R. K.

    2010-12-01

    Biogenically released isoprene is abundant in the troposphere, and has an essential function in determining atmospheric chemistry and important implications for plant metabolism. As a result, considerable effort has been made to understand the underlying mechanisms driving isoprene synthesis, particularly in the context of a rapidly changing environment. Recently, a number of studies have focused on the contribution of recently assimilated carbon as opposed to stored/alternative intracellular or extracellular carbon sources in the context of environmental stress. Results from these studies can offer clues about the importance of various carbon pools for isoprene production and elucidate the corresponding physiological changes that are responsible for these dynamic shifts in carbon allocation. We performed a 13CO2-labeling study using proton-transfer-reaction mass spectrometry (PTR-MS) to examine the kinetics of the incorporation of recently assimilated photosynthate into isoprene emitted from poplar (Poplar x canescens) under sub-ambient, ambient, and elevated CO2 growth conditions. We also monitored the importance of pyruvate-derived carbon for isoprene biosynthesis and obtained a detailed account of where individual carbons are derived from by analyzing the ratio of the 3C subunit of isoprene (M41+) (a fragment which contains two carbons from pyruvate) to the ratio of the parent isoprene molecule (M69+). Dynamics in the M41+:M69+ ratio indicate that recently assimilated carbon is incorporated into the pyruvate carbon pool slowly across all CO2 treatments and is therefore accessible for isoprene synthesis at a slower rate when compared to substrates derived directly from photosynthesis. Analysis of the rates of change for individual masses indicated that the carbon pools in trees grown in sub-ambient CO2 (200 ppm) are labeled ~2 times faster than those of trees grown in ambient or elevated CO2. Analysis of the total isoprene emission rates between treatments

  13. Little River Pond Mill a wind-powered lagoon aerator

    International Nuclear Information System (INIS)

    The Little River Pond Mill is a wind-driven surface aerator designed to be used in facultative wastewater treatment plants. The aerator consists of an eight-blade wind turbine which is mounted to a gear box that transmits torque through the shaft to the impeller. A swing tail rotates the turbine into the wind and stabilizes the unit in high winds. This study was designed to investigate how the Little River Pond Mill operated in a lagoon environment, how it affected the performance of the lagoon, and to measure the oxygen transfer rate for a field-determined wind speed. Strong mixing capabilities have been observed in both the dugout and the lagoon installations even at low windspeeds. With the installation of the aerator there was a reduction in BOD and NH3N. The oxygen transfer rate was found to be 1.47 g O2/W h at an average wind speed of 19 km/h. Due to the Pond Mill's low power requirement, this aeration efficiency has been rated as 'quite reasonable' for this wind speed. 5 refs., 10 figs

  14. Tailwater concerns and the history of turbine aeration

    International Nuclear Information System (INIS)

    All new proposals for hydropower development and many of the almost 300 hydroelectric projects which will be relicensed before 2000 will have to address the issue of minimum dissolved oxygen concentrations. This paper highlights some of the causes and concerns of low dissolved oxygen concentrations in releases from hydropower projects and describes the history of hydroturbine aeration for reaerating these releases

  15. Fin characteristics of aerator devices with lateral deflectors

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; LI Dan; MA Fei; QIAN Shang-tuo

    2013-01-01

    The fins will be formed if the lateral deflectors in the side-walls with a bottom aerator device are improperly designed,and the flow regime downstream of the aerator device will be worsened.In this paper,the height and the length of the fins induced by the lateral deflectors are theoretically analyzed along with their influencing factors,and the fin characteristics are experimentally investigated on the basis of the theoretical analysis.It is shown that the intensities of the fins are strongly dependent on the ratio of the lateral cavity length to the bottom cavity length,and other factors,like the working head,the height and the angle of the lateral deflector,the flow Froude number around the aerator device,affect the fins indirectly through the changes of the lateral cavity length.When an aerator device with lateral deflectors is designed,it is crucial to match the above mentioned ratio,and to make the ratio of the two cavity lengths less than 1.0 in order to avoid the generation of the fins.

  16. No-till bioenergy cropping systems effect on soil aeration

    Science.gov (United States)

    Bioenergy cropping systems have been proposed as a way to enhance United States energy security. However, research on soil quality, such as the effects of maize stover harvesting on soil aeration and the relationships to soil structure and water, associated with bioenergy cropping systems has been l...

  17. HYDRAULIC CHARACTERISTICS OF CHUTE AERATORS FOR RELEASE WORKS

    Institute of Scientific and Technical Information of China (English)

    RUAN Shi-ping

    2008-01-01

    On the basis of model tests and theoretical analysis, hydraulic characteristics, air demand, air concentration distribution and their relationships between prototype and model of an aerator were studied. Some computational examples show that the present methods have higher accuracy, and can meet the need of engineering design.

  18. Aeration of bread dough influenced by different way processing

    NARCIS (Netherlands)

    Peighambardoust, S.H.; Fallah, E.; Hamer, R.J.; Goot, van der A.J.

    2010-01-01

    The effect of steady shearing versus z-blade mixing on mechanical aeration and gas retaining ability of the dough during processing and subsequent proofing and bread baking stages was investigated. Reduction in moisture content led to reduction in both static and dynamic densities of z-blade mixed d

  19. Nutrients removal using moving beds with aeration cycles

    International Nuclear Information System (INIS)

    Moving Bed Biofilm Reactors (MBBR) are based on the biomass growth over a media that moves into the reactor due to aeration, mechanical agitation or recirculation. These reactors have been gaining popularity and they are employed in hundreds of plants everywhere with different treatment purposes (organic matter removal, nitrification/denitrification), both for urban and industrial wastewater. (Author)

  20. Effect of auxotrophies on yeast performance in aerated fed-batch reactor

    Energy Technology Data Exchange (ETDEWEB)

    Landi, Carmine; Paciello, Lucia [Dept. Ingegneria Industriale, Universita di Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno (Italy); Alteriis, Elisabetta de [Dept. Biologia Strutturale e Funzionale, Universita degli Studi di Napoli ' Federico II' , Via Cinthia, 80100 Napoli (Italy); Brambilla, Luca [Dept. Biotecnologie e Bioscienze, Universita Milano-Bicocca, Piazza della Scienza, 20126 Milano (Italy); Parascandola, Palma, E-mail: pparascandola@unisa.it [Dept. Ingegneria Industriale, Universita di Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno (Italy)

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer The paper contributes to fill the gap existing between the basic and applied research. Black-Right-Pointing-Pointer Mathematical model sheds light on the physiology of auxotrophic yeast strains. Black-Right-Pointing-Pointer Yeast behavior in fed-batch is influenced by biological and environmental determinants. Black-Right-Pointing-Pointer Process optimization would make possible the production of heterologous proteins which are not yet on the market. -- Abstract: A systematic investigation on the effects of auxotrophies on the performance of yeast in aerated fed-batch reactor was carried out. Six isogenic strains from the CEN.PK family of Saccharomyces cerevisiae, one prototroph and five auxotrophs, were grown in aerated fed-batch reactor using the same operative conditions and a proper nutritional supplementation. The performance of the strains, in terms of final biomass decreased with increasing the number of auxotrophies. Auxotrophy for leucine exerted a profound negative effect on the performance of the strains. Accumulation of reactive oxygen species (ROS) in the cells of the strain carrying four auxotrophies and its significant viability loss, were indicative of an oxidative stress response induced by exposure of cells to the environmental conditions. The mathematical model was fundamental to highlight how the carbon flux, depending on the number and type of auxotrophies, was diverted towards the production of increasingly large quantities of energy for maintenance.

  1. Effect of auxotrophies on yeast performance in aerated fed-batch reactor

    International Nuclear Information System (INIS)

    Highlights: ► The paper contributes to fill the gap existing between the basic and applied research. ► Mathematical model sheds light on the physiology of auxotrophic yeast strains. ► Yeast behavior in fed-batch is influenced by biological and environmental determinants. ► Process optimization would make possible the production of heterologous proteins which are not yet on the market. -- Abstract: A systematic investigation on the effects of auxotrophies on the performance of yeast in aerated fed-batch reactor was carried out. Six isogenic strains from the CEN.PK family of Saccharomyces cerevisiae, one prototroph and five auxotrophs, were grown in aerated fed-batch reactor using the same operative conditions and a proper nutritional supplementation. The performance of the strains, in terms of final biomass decreased with increasing the number of auxotrophies. Auxotrophy for leucine exerted a profound negative effect on the performance of the strains. Accumulation of reactive oxygen species (ROS) in the cells of the strain carrying four auxotrophies and its significant viability loss, were indicative of an oxidative stress response induced by exposure of cells to the environmental conditions. The mathematical model was fundamental to highlight how the carbon flux, depending on the number and type of auxotrophies, was diverted towards the production of increasingly large quantities of energy for maintenance.

  2. Monitoring CO2 sources and sinks from space : the Orbiting Carbon Observatory (OCO) Mission

    Science.gov (United States)

    Crisp, David

    2006-01-01

    NASA's Orbiting Carbon Observatory (OCO) will make the first space-based measurements of atmospheric carbon dioxide (CO2) with the precision, resolution, and coverage needed to characterize the geographic distribution of CO2 sources and sinks and quantify their variability over the seasonal cycle. OCO is currently scheduled for launch in 2008. The observatory will carry a single instrument that incorporates three high-resolution grating spectrometers designed to measure the near-infrared absorption by CO2 and molecular oxygen (O2) in reflected sunlight. OCO will fly 12 minutes ahead of the EOS Aqua platform in the Earth Observing System (EOS) Afternoon Constellation (A-Train). The in-strument will collect 12 to 24 soundings per second as the Observatory moves along its orbit track on the day side of the Earth. A small sampling footprint (sinks of CO2. This information could play an important role in monitoring the integrity of large scale CO2 sequestration projects.

  3. Monitoring CO2 sources and sinks from space : the Orbiting Carbon Observatory (OCO) Mission

    Science.gov (United States)

    Crisp, David

    2006-01-01

    NASA's Orbiting Carbon Observatory (OCO) will make the first space-based measurements of atmospheric carbon dioxide (CO2) with the precision, resolution, and coverage needed to characterize the geographic distribution of CO2 sources and sinks and quantify their variability over the seasonal cycle. OCO is currently scheduled for launch in 2008. The observatory will carry a single instrument that incorporates three high-resolution grating spectrometers designed to measure the near-infrared absorption by CO2 and molecular oxygen (O2) in reflected sunlight. OCO will fly 12 minutes ahead of the EOS Aqua platform in the Earth Observing System (EOS) Afternoon Constellation (A-Train). The in-strument will collect 12 to 24 soundings per second as the Observatory moves along its orbit track on the day side of the Earth. A small sampling footprint (CO2. This information could play an important role in monitoring the integrity of large scale CO2 sequestration projects.

  4. Widely Tunable Single-Photon Source from a Carbon Nanotube in the Purcell Regime

    Science.gov (United States)

    Jeantet, A.; Chassagneux, Y.; Raynaud, C.; Roussignol, Ph.; Lauret, J. S.; Besga, B.; Estève, J.; Reichel, J.; Voisin, C.

    2016-06-01

    The narrow emission of a single carbon nanotube at low temperature is coupled to the optical mode of a fiber microcavity using the built-in spatial and spectral matching brought by this flexible geometry. A thorough cw and time-resolved investigation of the very same emitter both in free space and in cavity shows an efficient funneling of the emission into the cavity mode together with a strong emission enhancement corresponding to a Purcell factor of up to 5. At the same time, the emitted photons retain a strong sub-Poissonian statistics. By exploiting the cavity feeding effect on the phonon wings, we locked the emission of the nanotube at the cavity resonance frequency, which allowed us to tune the frequency over a 4 THz band while keeping an almost perfect antibunching. By choosing the nanotube diameter appropriately, this study paves the way to the development of carbon-based tunable single-photon sources in the telecom bands.

  5. Diamond-Like Carbon Film Deposition Using DC Ion Source with Cold Hollow Cathode

    Directory of Open Access Journals (Sweden)

    E. F. Shevchenko

    2014-01-01

    Full Text Available Carbon diamond-like thin films on a silicon substrate were deposited by direct reactive ion beam method with an ion source based on Penning direct-current discharge system with cold hollow cathode. Deposition was performed under various conditions. The pressure (12–200 mPa and the plasma-forming gas composition consisting of different organic compounds and hydrogen (C3H8, CH4, Si(CH32Cl2, H2, the voltage of accelerating gap in the range 0.5–5 kV, and the substrate temperature in the range 20–850°C were varied. Synthesized films were researched using nanoindentation, Raman, and FTIR spectroscopy methods. Analysis of the experimental results was made in accordance with a developed model describing processes of growth of the amorphous and crystalline carbon materials.

  6. Tempeh Waste as a Natural, Economical Carbon and Nutrient Source: ED-XRF and NCS Study

    Directory of Open Access Journals (Sweden)

    SITI KHODIJAH CHAERUN

    2009-09-01

    Full Text Available The purpose of this study was to determine the elemental composition of three types of waste from tempeh production. They are soybean hull “tempeh waste” after dehulling soybeans, tempeh wastewater after soaking dehulled soybeans in water for 24 h, and tempeh wastewater after boiling dehulled soybeans in water for 30 min. By using ED-XRF analyzer, it was revealed that tempeh waste contained Mg, Si, P, S, K, Ca, Mn, Fe, and Zn. The highest elemental content was K, followed by Ca, P, and Mg. NCS analysis showed that tempeh waste was composed of C, N, and S with C/N ratio of 11.20. The present study provides evidence that both tempeh waste and wastewater are rich in carbon and nutrient contents, thus their potential for both inorganic and organic nutrient and carbon sources for microbial growth in bioremediation or as natural NPK fertilizers is promising.

  7. Carbon Nanotube Bundle Array Cold Cathodes for THz Vacuum Tube Sources

    Science.gov (United States)

    Manohara, Harish M.; Toda, Risaku; Lin, Robert H.; Liao, Anna; Bronikowski, Michael J.; Siegel, Peter H.

    2009-12-01

    We present high performance cold cathodes composed of arrays of carbon nanotube bundles that routinely produce > 15 A/cm2 at applied fields of 5 to 8 V/µm without any beam focusing. They have exhibited robust operation in poor vacuums of 10-6 to 10-4 Torr- a typically achievable range inside hermetically sealed microcavities. A new double-SOI process was developed to monolithically integrate a gate and additional beam tailoring electrodes. The ability to design the electrodes for specific requirements makes carbon nanotube field emission sources extremely flexible. The lifetime of these cathodes is found to be affected by two effects: a gradual decay of emission due to anode sputtering, and catastrophic failure because of dislodging of CNT bundles at high fields ( > 10 V/µm).

  8. Alginate Production from Alternative Carbon Sources and Use of Polymer Based Adsorbent in Heavy Metal Removal

    Directory of Open Access Journals (Sweden)

    Çiğdem Kıvılcımdan Moral

    2016-01-01

    Full Text Available Alginate is a biopolymer composed of mannuronic and guluronic acids. It is harvested from marine brown algae; however, alginate can also be synthesized by some bacterial species, namely, Azotobacter and Pseudomonas. Use of pure carbohydrate sources for bacterial alginate production increases its cost and limits the chance of the polymer in the industrial market. In order to reduce the cost of bacterial alginate production, molasses, maltose, and starch were utilized as alternative low cost carbon sources in this study. Results were promising in the case of molasses with the maximum 4.67 g/L of alginate production. Alginates were rich in mannuronic acid during early fermentation independent of the carbon sources while the highest guluronic acid content was obtained as 68% in the case of maltose. The polymer was then combined with clinoptilolite, which is a natural zeolite, to remove copper from a synthetic wastewater. Alginate-clinoptilolite beads were efficiently adsorbed copper up to 131.6 mg Cu2+/g adsorbent at pH 4.5 according to the Langmuir isotherm model.

  9. Metabolic engineering of Corynebacterium glutamicum aimed at alternative carbon sources and new products.

    Science.gov (United States)

    Zahoor, Ahmed; Lindner, Steffen N; Wendisch, Volker F

    2012-01-01

    Corynebacterium glutamicum is well known as the amino acid-producing workhorse of fermentation industry, being used for multi-million-ton scale production of glutamate and lysine for more than 60 years. However, it is only recently that extensive research has focused on engineering it beyond the scope of amino acids. Meanwhile, a variety of corynebacterial strains allows access to alternative carbon sources and/or allows production of a wide range of industrially relevant compounds. Some of these efforts set new standards in terms of titers and productivities achieved whereas others represent a proof-of-principle. These achievements manifest the position of C. glutamicum as an important industrial microorganism with capabilities far beyond the traditional amino acid production. In this review we focus on the state of the art of metabolic engineering of C. glutamicum for utilization of alternative carbon sources, (e.g. coming from wastes and unprocessed sources), and construction of C. glutamicum strains for production of new products such as diamines, organic acids and alcohols. PMID:24688664

  10. Metabolic engineering of Corynebacterium glutamicum aimed at alternative carbon sources and new products

    Directory of Open Access Journals (Sweden)

    Volker Fritz Wendisch

    2012-10-01

    Full Text Available Corynebacterium glutamicum is well known as the amino acid-producing workhorse of fermentation industry, being used for multi-million-ton scale production of glutamate and lysine for more than 60 years. However, it is only recently that extensive research has focused on engineering it beyond the scope of amino acids. Meanwhile, a variety of corynebacterial strains allows access to alternative carbon sources and/or allows production of a wide range of industrially relevant compounds. Some of these efforts set new standards in terms of titers and productivities achieved whereas others represent a proof-of-principle. These achievements manifest the position of C. glutamicum as an important industrial microorganism with capabilities far beyond the traditional amino acid production. In this review we focus on the state of the art of metabolic engineering of C. glutamicum for utilization of alternative carbon sources, (e.g. coming from wastes and unprocessed sources, and construction of C. glutamicum strains for production of new products such as diamines, organic acids and alcohols.

  11. Production of bacterial cellulose using different carbon sources and culture media.

    Science.gov (United States)

    Mohammadkazemi, Faranak; Azin, Mehrdad; Ashori, Alireza

    2015-03-01

    In this work, the effects of carbon sources and culture media on the production and structural properties of bacterial cellulose (BC) have been studied. BC nanofibers were synthesized using Gluconacetobacter xylinus strain PTCC 1734. Media used were Hestrin-Schramm (H), Yamanaka (Y), and Zhou (Z). Five different carbon sources, namely date syrup, glucose, mannitol, sucrose, and food-grade sucrose were used in these media. All the produced BC pellicles were characterized in terms of dry weight production, biomass yield, thermal stability, crystallinity and morphology by thermogravimetric analysis (TGA), x-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The obtained results showed that mannitol lead to the highest yield, followed by sucrose. The highest production efficiency of mannitol might be due to the nitrogen source, which plays an important role. The maximum improvement on the thermal stability of the composites was achieved when mannitol was used in H medium. In addition, the crystallinity was higher in BC formed in H medium compared to other media. FE-SEM micrographs illustrated that the BC pellicles, synthesized in the culture media H and Z, were stable, unlike those in medium Y that were unstable. The micrographs of BC produced in media containing mannitol and sucrose provided evidence of the strong interfacial adhesion between the BC fibers without noticeable aggregates. PMID:25498666

  12. Batch fermentation model of propionic acid production by Propionibacterium acidipropionici in different carbon sources.

    Science.gov (United States)

    Coral, Jefferson; Karp, Susan Grace; Porto de Souza Vandenberghe, Luciana; Parada, José Luis; Pandey, Ashok; Soccol, Carlos Ricardo

    2008-12-01

    Propionic acid (PA) is widely used as additive in animal feed and also in the manufacturing of cellulose-based plastics, herbicides, and perfumes. Salts of propionic acid are used as preservative in food. PA is mainly produced by chemical synthesis. Nowadays, PA production by fermentation of low-cost industrial wastes or renewable sources has been an interesting alternative. In the present investigation, PA production by Propionibacterium acidipropionici ATCC 4965 was studied using a basal medium with sugarcane molasses (BMSM), glycerol or lactate (BML) in small batch fermentation at 30 and 36 degrees C. Bacterial growth was carried out under low dissolved oxygen concentration and without pH control. Results indicated that P. acidipropionici produced more biomass in BMSM than in other media at 30 degrees C (7.55 g l(-1)) as well as at 36 degrees C (3.71 g l(-1)). PA and biomass production were higher at 30 degrees C than at 36 degrees C in all cases studied. The best productivity was obtained by using BML (0.113 g l(-1) h(-1)), although the yielding of this metabolite was higher when using glycerol as carbon source (0.724 g g(-1)) because there was no detection of acetic acid. By the way, when using the other two carbon sources, acetic acid emerged as an undesirable by-product for further PA purification. PMID:18386184

  13. Liquid and atmospheric ammonia concentrations from a dairy lagoon during an aeration experiment

    Science.gov (United States)

    Rumburg, Brian; Neger, Manjit; Mount, George H.; Yonge, David; Filipy, Jenny; Swain, John; Kincaid, Ron; Johnson, Kristen

    Ammonia emissions from agriculture are an environmental and human health concern, and there is increasing pressure to reduce emissions. Animal agriculture is the largest global source of ammonia emissions and on a per cow basis dairy operations are the largest emitters. The storage and disposal of the dairy waste is one area where emissions can be reduced, aerobic biological treatment of wastewater being a common and effective way of reducing ammonia emissions. An aeration experiment in a dairy lagoon with two commercial aerators was performed for 1 month. Liquid concentrations of ammonia, total nitrogen, nitrite and nitrate were monitored before, during and after the experiment and atmospheric ammonia was measured downwind of the lagoon using a short-path differential optical absorption spectroscopy (DOAS) instrument with 1 ppbv sensitivity. No changes in either liquid or atmospheric ammonia concentrations were detected throughout the experiment, and neither dissolved oxygen, nitrite nor nitrate could be detected in the lagoon at any time. The average ammonia concentration at 10 sampling sites in the lagoon at a depth of 0.15 m was 650 mg l -1 and at 0.90 m it was 700 mg l -1 NH 3-N. The average atmospheric ammonia concentration 50 m downwind was about 300 ppbv. The 0.90 m depth total nitrogen concentrations and total and volatile solids concentrations decreased during the experiment due to some mixing of the lagoon but the 0.15 m depth concentrations did not decrease indicating that the aerators were not strong enough to mix the sludge off the bottom into the whole water column.

  14. In silico carbon molecular beam epitaxial growth of graphene on the h-BN substrate: carbon source effect on van der Waals epitaxy

    Science.gov (United States)

    Lee, Jonghoon; Varshney, Vikas; Park, Jeongho; Farmer, Barry L.; Roy, Ajit K.

    2016-05-01

    Against the presumption that hexagonal boron-nitride (h-BN) should provide an ideal substrate for van der Waals (vdW) epitaxy to grow high quality graphene films, carbon molecular beam epitaxy (CMBE) techniques using solid carbon sublimation have reported relatively poor quality of the graphene. In this article, the CMBE growth of graphene on the h-BN substrate is numerically studied in order to identify the effect of the carbon source on the quality of the graphene film. The carbon molecular beam generated by the sublimation of solid carbon source materials such as graphite and glassy carbon is mostly composed of atomic carbon, carbon dimers and carbon trimers. Therefore, the graphene film growth becomes a complex process involving various deposition characteristics of a multitude of carbon entities. Based on the study of surface adsorption and film growth characteristics of these three major carbon entities comprising graphite vapour, we report that carbon trimers convey strong traits of vdW epitaxy prone to high quality graphene growth, while atomic carbon deposition is a surface-reaction limited process accompanied by strong chemisorption. The vdW epitaxial behaviour of carbon trimers is found to be substantial enough to nucleate and develop into graphene like planar films within a nanosecond of high flux growth simulation, while reactive atomic carbons tend to impair the structural integrity of the crystalline h-BN substrate upon deposition to form an amorphous interface between the substrate and the growing carbon film. The content of reactive atomic carbons in the molecular beam is suspected to be the primary cause of low quality graphene reported in the literature. A possible optimization of the molecular beam composition towards the synthesis of better quality graphene films is suggested.Against the presumption that hexagonal boron-nitride (h-BN) should provide an ideal substrate for van der Waals (vdW) epitaxy to grow high quality graphene films, carbon

  15. Optimal Medium Composition to Enhance Poly-β-hydroxybutyrate Production by Ralstonia eutropha Using Cane Molasses as Sole Carbon Source

    OpenAIRE

    Ali Bozorg; Manouchehr Vossoughi; Akhtarolmoluk Kazemi; Iran Alemzadeh

    2015-01-01

    In order to reduce the costs associated with Poly-β-hydroxybutyrate production, growth and Poly-β-hydroxybutyrate production of Ralstonia eutropha were studied in batch culture on different carbon sources. Experiments were designed and conducted to not only lower the cost of Poly-β-hydroxybutyrate production by using inexpensive substrates, but also to increase Poly-β-hydroxybutyrate production by optimizing the culture medium composition. Low cost, abundant carbon sources, including cane mol...

  16. Enhanced biological nutrient removal in modified carbon source division anaerobic anoxic oxic process with return activated sludge pre-concentration☆

    Institute of Scientific and Technical Information of China (English)

    Qin Lu; Haiyan Wu; Haoyan Li; Dianhai Yang

    2015-01-01

    A pilot-scale modified carbon source division anaerobic anoxic oxic (AAO) process with pre-concentration of returned activated sludge (RAS) was proposed in this study for the enhanced biological nutrient removal (BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60%and 50%, respectively, with an inner recycling ratio of 100%under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L−1 with a removal efficiency of 63%and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.

  17. Changes in the Acetylome and Succinylome of Bacillus subtilis in Response to Carbon Source.

    Directory of Open Access Journals (Sweden)

    Saori Kosono

    Full Text Available Lysine residues can be post-translationally modified by various acyl modifications in bacteria and eukarya. Here, we showed that two major acyl modifications, acetylation and succinylation, were changed in response to the carbon source in the Gram-positive model bacterium Bacillus subtilis. Acetylation was more common when the cells were grown on glucose, glycerol, or pyruvate, whereas succinylation was upregulated when the cells were grown on citrate, reflecting the metabolic states that preferentially produce acetyl-CoA and succinyl-CoA, respectively. To identify and quantify changes in acetylation and succinylation in response to the carbon source, we performed a stable isotope labeling by amino acids in cell culture (SILAC-based quantitative proteomic analysis of cells grown on glucose or citrate. We identified 629 acetylated proteins with 1355 unique acetylation sites and 204 succinylated proteins with 327 unique succinylation sites. Acetylation targeted different metabolic pathways under the two growth conditions: branched-chain amino acid biosynthesis and purine metabolism in glucose and the citrate cycle in citrate. Succinylation preferentially targeted the citrate cycle in citrate. Acetylation and succinylation mostly targeted different lysine residues and showed a preference for different residues surrounding the modification sites, suggesting that the two modifications may depend on different factors such as characteristics of acyl-group donors, molecular environment of the lysine substrate, and/or the modifying enzymes. Changes in acetylation and succinylation were observed in proteins involved in central carbon metabolism and in components of the transcription and translation machineries, such as RNA polymerase and the ribosome. Mutations that modulate protein acylation affected B. subtilis growth. A mutation in acetate kinase (ackA increased the global acetylation level, suggesting that acetyl phosphate-dependent acetylation is

  18. Ventilation/perfusion mismatch during lung aeration at birth.

    Science.gov (United States)

    Lang, Justin A R; Pearson, James T; te Pas, Arjan B; Wallace, Megan J; Siew, Melissa L; Kitchen, Marcus J; Fouras, Andreas; Lewis, Robert A; Wheeler, Kevin I; Polglase, Graeme R; Shirai, Mikiyasu; Sonobe, Takashi; Hooper, Stuart B

    2014-09-01

    At birth, the transition to newborn life is triggered by lung aeration, which stimulates a large increase in pulmonary blood flow (PBF). Current theories predict that the increase in PBF is spatially related to ventilated lung regions as they aerate after birth. Using simultaneous phase-contrast X-ray imaging and angiography we investigated the spatial relationships between lung aeration and the increase in PBF after birth. Six near-term (30-day gestation) rabbits were delivered by caesarean section, intubated and an intravenous catheter inserted, before they were positioned for X-ray imaging. During imaging, iodine was injected before ventilation onset, after ventilation of the right lung only, and after ventilation of both lungs. Unilateral ventilation increased iodine levels entering both left and right pulmonary arteries (PAs) and significantly increased heart rate, iodine ejection per beat, diameters of both left and right PAs, and number of visible vessels in both lungs. Within the 6th intercostal space, the mean gray level (relative measure of iodine level) increased from 68.3 ± 11.6 and 70.3 ± 7.5%·s to 136.3 ± 22.6 and 136.3 ± 23.7%·s in the left and right PAs, respectively. No differences were observed between vessels in the left and right lungs, despite the left lung not initially being ventilated. The increase in PBF at birth is not spatially related to lung aeration allowing a large ventilation/perfusion mismatch, or pulmonary shunting, to occur in the partially aerated lung at birth. PMID:24994883

  19. The potential for aeration of MSW landfills to accelerate completion

    International Nuclear Information System (INIS)

    Landfilling is a popular waste disposal method, but, as it is practised currently, it is fundamentally unsustainable. The low short-term financial costs belie the potential long-term environmental costs, and traditional landfill sites require long-term management in order to mitigate any possible environmental damage. Old landfill sites might require aftercare for decades or even centuries, and in some cases remediation may be necessary. Biological stabilisation of a landfill is the key issue; completion criteria provide a yardstick by which the success of any new technology may be measured. In order for a site to achieve completion it must pose no risk to human health or the environment, meaning that attenuation of any emissions from the site must occur within the local environment without causing harm. Remediation of old landfill sites by aerating the waste has been undertaken in Germany, the United States, Italy and The Netherlands, with considerable success. At a pilot scale, aeration has also been used in newly emplaced waste to accelerate stabilisation. This paper reviews the use of aerobic landfill worldwide, and assesses the ways in which the use of aerobic landfill techniques can decrease the risks associated with current landfill practices, making landfill a more sustainable waste disposal option. It focuses on assessing ways to utilise aeration to enhance stabilisation. The results demonstrated that aeration of old landfill sites may be an efficient and cost-effective method of remediation and allow the date of completion to be brought forward by decades. Similarly, aeration of newly emplaced waste can be effective in enhancing degradation, assisting with completion and reducing environmental risks. However, further research is required to establish what procedure for adding air to a landfill would be most suitable for the UK and to investigate new risks that may arise, such as the possible emission of non-methane organic compounds

  20. Compound specific radiocarbon analyses to apportion sources of combustion products in sedimentary pyrogenic carbon deposits

    Science.gov (United States)

    Hanke, Ulrich M.; Schmidt, Michael W. I.; McIntyre, Cameron P.; Reddy, Christopher M.; Wacker, Lukas; Eglinton, Timothy I.

    2016-04-01

    Pyrogenic carbon (PyC) is a collective term for carbon-rich residues comprised of a continuum of products generated during biomass burning and fossil fuel combustion. PyC is a key component of the global carbon cycle due to its slow intrinsic decomposition rate and its ubiquity in the environment. It can originate from natural or anthropogenic vegetation fires, coal mining, energy production, industry and transport. Subsequently, PyC can be transported over long distances by wind and water and can eventually be buried in sediments. Information about the origin of PyC (biomass burning vs. fossil fuel combustion) deposited in estuarine sediments is scarce. We studied the highly anoxic estuarine sediments of the Pettaquamscutt River (Rhode Island, U.S.) in high temporal resolution over 250 years and found different combustion proxies reflect local and regional sources of PyC (Hanke et al. in review; Lima et al. 2003). The polycyclic aromatic hydrocarbons (PAH) originate from long-range atmospheric transport, whereas bulk PyC, detected as benzene polycarboxylic acids (BPCA), mainly stems from local catchment run-off. However, to unambiguously apportion PyC sources, we need additional information, such as compound specific radiocarbon (14C) measurements. We report 14C data for individual BPCA including error analysis and for combustion-related PAH. First results indicate that biomass burning is the main source of PyC deposits, with additional minor contributions from fossil fuel combustion. References Hanke U.M., T.I. Eglinton, A.L.L. Braun, C. Reddy, D.B. Wiedemeier, M.W.I. Schmidt. Decoupled sedimentary records of combustion: causes and implications. In review. Lima, A. L.; Eglinton, T. I.; Reddy, C. M., High-resolution record of pyrogenic polycyclic aromatic hydrocarbon deposition during the 20th century. ES&T, 2003, 37 (1), 53-61.

  1. Glucosamine as carbon source for amino acid-producing Corynebacterium glutamicum.

    Science.gov (United States)

    Uhde, Andreas; Youn, Jung-Won; Maeda, Tomoya; Clermont, Lina; Matano, Christian; Krämer, Reinhard; Wendisch, Volker F; Seibold, Gerd M; Marin, Kay

    2013-02-01

    Corynebacterium glutamicum grows with a variety of carbohydrates and carbohydrate derivatives as sole carbon sources; however, growth with glucosamine has not yet been reported. We isolated a spontaneous mutant (M4) which is able to grow as fast with glucosamine as with glucose as sole carbon source. Glucosamine also served as a combined source of carbon, energy and nitrogen for the mutant strain. Characterisation of the M4 mutant revealed a significantly increased expression of the nagB gene encoding the glucosamine-6P deaminase NagB involved in degradation of glucosamine, as a consequence of a single mutation in the promoter region of the nagAB-scrB operon. Ectopic nagB overexpression verified that the activity of the NagB enzyme is in fact the growth limiting factor under these conditions. In addition, glucosamine uptake was studied, which proved to be unchanged in the wild-type and M4 mutant strains. Using specific deletion strains, we identified the PTS(Glc) transport system to be responsible for glucosamine uptake in C. glutamicum. The affinity of this uptake system for glucosamine was about 40-fold lower than that for its major substrate glucose. Because of this difference in affinity, glucosamine is efficiently taken up only if external glucose is absent or present at low concentrations. C. glutamicum was also examined for its suitability to use glucosamine as substrate for biotechnological purposes. Upon overexpression of the nagB gene in suitable C. glutamicum producer strains, efficient production of both the amino acid L-lysine and the diamine putrescine from glucosamine was demonstrated. PMID:22854894

  2. Rapid biological oxidation of methanol in the tropical Atlantic: significance as a microbial carbon source

    Directory of Open Access Journals (Sweden)

    J. L. Dixon

    2011-09-01

    Full Text Available Methanol is the second most abundant organic gas in the atmosphere after methane, and is ubiquitous in the troposphere. It plays a significant role in atmospheric oxidant chemistry and is biogeochemically active. Large uncertainties exist about whether the oceans are a source or sink of methanol to the atmosphere. Even less is understood about what reactions in seawater determine its concentration, and hence flux across the sea surface interface. We report here concentrations of methanol between 151–296 nM in parts of the oligotrophic North Atlantic, with corresponding microbial uptake rates between 2–146 nM d−1, suggesting turnover times as low as 1 day (1–25 days in surface waters of the oligotrophic tropical North East Atlantic. Methanol is mainly (≥97% used by microbes for obtaining energy in oligotrophic regions, which contrasts with shelf and coastal areas where between 20–50% can be used for cell growth. Comparisons of microbial methanol oxidation rates with parallel determinations of bacterial leucine uptake suggest that methanol contributes on average 13% to bacterial carbon demand in the central northern Atlantic gyre (maximum of 54%. In addition, the contribution that methanol makes to bacterial carbon demand varies as a power function of chlorophyll a concentrations; suggesting for concentrations <0.2 μg l−1 that methanol can make a significant contribution to bacterial carbon demand. However, our low air to sea methanol flux estimates of 7.2–13 μmol m−2 d−1 suggest that the atmosphere is not a major methanol source. We conclude that there must be a major, as yet unidentified, in situ oceanic methanol source in these latitudes which we suggest is sunlight driven decomposition of organic matter.

  3. Upscaling carbon fluxes over the Great Plains grasslands: Sinks and sources

    Science.gov (United States)

    Zhang, Li; Wylie, Bruce K.; Ji, Lei; Gilmanov, Tagir G.; Tieszen, Larry L.; Howar, Daniel M.

    2011-01-01

    Previous studies suggested that the grasslands may be carbon sinks or near equilibrium, and they often shift between carbon sources in drought years and carbon sinks in other years. It is important to understand the responses of net ecosystem production (NEP) to various climatic conditions across the U.S. Great Plains grasslands. Based on 15 grassland flux towers, we developed a piecewise regression model and mapped the grassland NEP at 250 m spatial resolution over the Great Plains from 2000 to 2008. The results showed that the Great Plains was a net sink with an averaged annual NEP of 24 ± 14 g C m−2 yr−1, ranging from a low value of 0.3 g C m−2 yr−1 in 2002 to a high value of 47.7 g C m−2 yr−1 in 2005. The regional averaged NEP for the entire Great Plains grasslands was estimated to be 336 Tg C yr−1 from 2000 to 2008. In the 9 year period including 4 dry years, the annual NEP was very variable in both space and time. It appeared that the carbon gains for the Great Plains were more sensitive to droughts in the west than the east. The droughts in 2000, 2002, 2006, and 2008 resulted in increased carbon losses over drought-affected areas, and the Great Plains grasslands turned into a relatively low sink with NEP values of 15.8, 0.3, 20.1, and 10.2 g C m−2 yr−1 for the 4 years, respectively.

  4. Nitrous oxide emissions from an intermittent aeration activated sludge system of an urban wastewater treatment plant

    OpenAIRE

    William Z. de Mello; Renato P. Ribeiro; Ariane C. Brotto; Débora C. Kligerman; Andrezza de S. Piccoli; Jaime L. M. Oliveira

    2013-01-01

    This study investigated the emission of N2O during the sequential aerated (60-min) and non-aerated (30-min) stages of an intermittent aeration cycle in an activated sludge wastewater treatment plant (WWTP). N2O emission occurred during both stages; however, emission was much higher during aeration. Air stripping is the major factor controlling transfer of N2O from the sewage to the atmosphere. The N2O emissions exclusively from the aeration tank represented 0.10% of the influent total nitroge...

  5. Growth of Bacteria on 3-Nitropropionic Acid as a Sole Source of Carbon, Nitrogen, and Energy▿

    OpenAIRE

    Nishino, Shirley F.; Shin, Kwanghee A.; Payne, Rayford B.; Spain, Jim C.

    2010-01-01

    3-Nitropropionic acid (3NPA) is a widespread nitroaliphatic toxin found in a variety of legumes and fungi. Several enzymes have been reported that can transform the compound, but none led to the mineralization of 3NPA. We report here the isolation of bacteria that grow on 3NPA and its anion, propionate-3-nitronate (P3N), as the sole source of carbon, nitrogen, and energy. Experiments with resting cells, cell extracts, and purified enzymes indicate that the pathway involves conversion of 3NPA ...

  6. Effects of added fertilizers and carbon source on the persistence of carbaryl in soils

    International Nuclear Information System (INIS)

    The effect of added fertilizers and carbon source on the persistence of carbaryl in two types of soils was investigated using the technique of liquid scintillation counting. In both soils, the addition of fertilzers (NPK) had little effect on the rate of degradation of carbaryl. In contrast, the addition of sucrose, with or without fertilizer increases degradation of carboryl in a yellow red latosol soil poor in organic matter but has little effect on the degradation in a humic gley soil rich in organic mutter. (Author)

  7. Metabolic Fluxes in Corynebacterium glutamicum during Lysine Production with Sucrose as Carbon Source

    OpenAIRE

    Wittmann, Christoph; Kiefer, Patrick; Zelder, Oskar

    2004-01-01

    Metabolic fluxes in the central metabolism were determined for lysine-producing Corynebacterium glutamicum ATCC 21526 with sucrose as a carbon source, providing an insight into molasses-based industrial production processes with this organism. For this purpose, 13C metabolic flux analysis with parallel studies on [1-13CFru]sucrose, [1-13CGlc]sucrose, and [13C6Fru]sucrose was carried out. C. glutamicum directed 27.4% of sucrose toward extracellular lysine. The strain exhibited a relatively hig...

  8. Low-cost carbon sources for the production of a thermostable xylanase by Aspergillus niger

    OpenAIRE

    Ana Cláudia Elias Pião Benedetti; Eliana Dantas da Costa; Caio Casale Aragon; Andréa Francisco dos Santos; Antônio José Goulart; Derlene Attili-Angelis; Rubens Monti

    2013-01-01

    A strain of the filamentous fungus Aspergillus niger was isolated and shown to possess extracellular xylanolytic activity. These enzymes have biotechnological potential and can be employed in various industries. This fungus produced its highest xylanase activity in a medium made up of 0.1% CaCO3 , 0.5% NaCl, 0.1% NH4 Cl, 0.5% corn steep liquor and 1% carbon source, at pH 8.0. A lowcost hemicellulose residue (powdered corncob) proved to be an excellent inducer of the A. ni...

  9. Stepwise bioprocess for exopolysaccharide production using potato starch as carbon source

    OpenAIRE

    Bhatia, Shashi Kant; Kumar, Narinder; Bhatia, Ravi Kant

    2014-01-01

    Xanthan gum is a biopolymer produced by Xanthomonas sp. XC6. In this study, xanthan gum is produced from potato starch using a stepwise bioprocess design. Potato starch is hydrolyzed using Bacillus sp. having amylase activity and 30.2 g/L reducing sugar was released, while Xanthomonas sp. XC6 can release only 14.5 g/L. Bacillus sp. hydrolyzed potato starch extract was further used as a carbon source for xanthan gum biosynthesis using Xanthomonas sp. XC6. Yeast extract acts as the best nitroge...

  10. Degraded peatlands as a source of riverine organic carbon and enhanced river outgassing in Sumatra, Indonesia

    Science.gov (United States)

    Wit, Francisca; Rixen, Tim

    2014-05-01

    Sumatra, Indonesia, is well known for its widespread tropical peat lands. However, silvi- and agricultural purposes are currently inducing large-scale degradation of peat lands, transforming the landscape into mainly palm-oil plantations. The degradation induces loss of carbon via direct CO2 emissions, but also via riverine outflow of dissolved and particulate organic carbon (DOC and POC, respectively) due to leaching. This organic carbon is then decomposed along the way towards the coast and is hypothesized to enhance coastal and river outgassing of CO2. In the framework of SPICE III, Science for the Protection of Indonesian Coastal Ecosystems, we are quantifying these carbon budgets and fluxes in the rivers and coastal areas of northeast Sumatra. Using underway instruments, we have gathered continuous measurements of various parameters, including pCO2, pH, temperature, salinity and oxygen. In addition, water samples were obtained for DOC, POC, δ13CDIC, alkalinity and nutrient analyses. The results of the first analyses show that pCO2 values in the coastal areas range between 400-600 μatm. However, in the vicinity of the rivers pCO2 concentrations increase tremendously, ranging from 600 near the estuaries to a staggering 9000 μatm further upstream. These values are much higher than the marine pCO2 value of 390 μatm in the South China Sea. When adding carbon isotope results into the story, while knowing that upstream river life is greatly reduced due to oxygen depletion as a result of high DOC decomposition, it appears to be clear from the values, which range between -20 to -24‰ δ13CDIC, that the main source of the organic carbon is indeed originating from the degrading peat lands. In conclusion, our hypothesis can be deemed correct: degrading peat lands enhance organic carbon outflow and therefore elevated decomposition in the rivers, which results in increased river outgassing of CO2. Further analyses will be conducted to precisely quantify the budgets and

  11. Redox potential driven aeration during very-high-gravity ethanol fermentation by using flocculating yeast.

    Science.gov (United States)

    Liu, Chen-Guang; Hao, Xue-Mi; Lin, Yen-Han; Bai, Feng-Wu

    2016-01-01

    Ethanol fermentation requires oxygen to maintain high biomass and cell viability, especially under very-high-gravity (VHG) condition. In this work, fermentation redox potential (ORP) was applied to drive the aeration process at low dissolved oxygen (DO) levels, which is infeasible to be regulated by a DO sensor. The performance and characteristics of flocculating yeast grown under 300 and 260 g glucose/L conditions were subjected to various aeration strategies including: no aeration; controlled aeration at -150, -100 and -50 mV levels; and constant aeration at 0.05 and 0.2 vvm. The results showed that anaerobic fermentation produced the least ethanol and had the highest residual glucose after 72 h of fermentation. Controlled aerations, depending on the real-time oxygen demand, led to higher cell viability than the no-aeration counterpart. Constant aeration triggered a quick biomass formation, and fast glucose utilization. However, over aeration at 0.2 vvm caused a reduction of final ethanol concentration. The controlled aeration driven by ORP under VHG conditions resulted in the best fermentation performance. Moreover, the controlled aeration could enhance yeast flocculating activity, promote an increase of flocs size, and accelerate yeast separation near the end of fermentation. PMID:27161047

  12. Performance of completely autotrophic nitrogen removal over nitrite process under different aeration modes and dissolved oxygen

    Institute of Scientific and Technical Information of China (English)

    Jinsong GUO; Guohong YANG; Fang FANG; Yu QIN

    2008-01-01

    In this study, three sequential batch biofilm reactors (SBBRs) were operated for 155 days to evaluate the performance of completely autotrophic nitrogen removal over nitrite (CANON) process under different aeration modes and dissolved oxygen (DO). Synthetic wastewater with 160-mg NH4+-N/L was fed into the reac-tors. In the continuously-aerated reactor, the efficiency of the ammonium nitrogen conversion and total nitrogen (TN) removal reached 80% and 70%, respectively, with DO between 0.8-1.0 mg/L. Whereas in the intermit-tently-aerated reactor, at the aeration/non-aeration ratio of 1.0, ammonium was always under the detection limit and 86% of TN was removed with DO between 2.0 2.5 mg/L during the aeration time. Results show that CANON could be achieved in both continuous and inter-mittent aeration pattern. However, to achieve the same nitrogen removal efficiency, the DO needed in the inter-mittently-aerated sequential batch biofilm reactor (SBBR) during the aeration period was higher than that in the continuously-aerated SBBR. In addition, the DO in the CANON system should be adjusted to the aeration mode, and low DO was not a prerequisite to CANON process.

  13. Silicon nanowire and carbon nanotube hybrid for room temperature multiwavelength light source.

    Science.gov (United States)

    Lo Faro, Maria Josè; D'Andrea, Cristiano; Messina, Elena; Fazio, Barbara; Musumeci, Paolo; Reitano, Riccardo; Franzò, Giorgia; Gucciardi, Pietro Giuseppe; Vasi, Cirino; Priolo, Francesco; Iacona, Fabio; Irrera, Alessia

    2015-01-01

    The realization of an innovative hybrid light source operating at room temperature, obtained by embedding a carbon nanotube (CNT) dispersion inside a Si nanowire (NW) array is reported. The NW/CNT system exhibits a peculiar photoluminescence spectrum, consisting of a wide peak, mainly observed in the visible range, due to quantum confined Si NWs, and of several narrower IR peaks, due to the different CNT chiralities present in the dispersion. The detailed study of the optical properties of the hybrid system evidences that the ratio between the intensity of the visible and the IR emissions can be varied within a wide range by changing the excitation wavelength or the CNT concentration; the conditions leading to the prevalence of one signal with respect to the other are identified. The multiplicity of emission spectra obtainable from this composite material opens new perspectives for Si nanostructures as active medium in light sources for Si photonics applications. PMID:26592198

  14. Carbon and nitrogen stable isotopes in coastal benthic populations under multiple organic enrichment sources

    International Nuclear Information System (INIS)

    In a dispersive coastal area under multiple organic enrichment sources, stable isotopes were used to trace organic sources of carbon and nitrogen in sediments and benthic macrofauna. The Bivalve Abra alba and the Polychaetes Nephtys sp. and Pectinaria (Lagis) koreni were reliable indicators of the input of terrestrial-derived organic matter into this coastal area, either originated in outfall sewage discharges or estuarine outflow. An isotopic depletion was observed up to 250 m from the outfall branches, much stronger in the biota than in the sediments. An enrichment of 2 per mille in the sediments, and 2-6 per mille in the species was noticed in sites located farther than 1500 m from the outfall. Depositivores and carnivores/omnivores gave the best picture of the extension of the sewage dispersion and incorporation into the food web.

  15. The forest as a historic source and sink for carbon dioxide; Skogen som historisk kaella respektive saenka foer koldioxid

    Energy Technology Data Exchange (ETDEWEB)

    Kander, A. [Lund Univ. (Sweden). Dept. of Economic History

    1996-06-01

    The aim of the present project is to quantify the changes in the growing stock of timber between 1800 and 1985 in order to find out under which periods and to what extent the forest has served as a source resp. sink for carbon dioxide. These data are compared to the carbon dioxide emissions from combustion of fossil fuels under the same period. Another goal of the project is to find the order of magnitude of the effect of other potential sinks and sources for carbon dioxide. 32 refs, 9 figs, 1 tab

  16. Distinct patterns of microbial metabolism associated to riverine dissolved organic carbon of different source and quality

    Science.gov (United States)

    Berggren, Martin; Giorgio, Paul A.

    2015-06-01

    Dissolved organic carbon (DOC) in rivers contains a wide range of molecules that can be assimilated by microbes. However, there is today no integrated understanding of how the source and composition of this DOC regulate the extent to which the DOC can support microbial growth and respiration. We analyzed patterns in microbial metabolism of DOC from different streams and rivers in Québec, by combining short-term bacterial production and respiration measurements with long-term DOC loss and analyses of bacterial use of different single substrates. We show that distinct metabolic patterns indeed exist across catchments, reflecting the varying nature and sources of the DOC. For example, DOC from forest headwaters systematically supported the highest bacterial growth efficiency (BGE) that was recorded, while in contrast DOC in peat bog drainage was used with significantly lower BGE. The carbon consumption in clear mountain rivers, possibly represented by autochthonous algal DOC, supported the highest bacterial respiration rates and the highest long-term DOC losses. By using principle component analysis, we demonstrate how the major axes of variation in all of the measured metabolic responses are tightly connected to spectrofluorometrical DOC composition indicators and to isotopic indicators of DOC source. If causality is assumed, our results imply that changes in DOC supply from different sources, for example, caused by land use or climate change, should result in dramatic changes in the patterns of aquatic microbial metabolism and thus in altered aquatic ecosystem functioning, with likely consequences for food-web structures and greenhouse gas balances.

  17. Identifying dissolved organic carbon sources at a gaged headwater catchment using FDOM sensors

    Science.gov (United States)

    Malzone, J. M.; Shanley, J. B.

    2014-12-01

    The United States Geological Survey's (USGS) W-9 gage at the headwaters of Sleepers River, Vermont has been monitored for dissolved organic carbon (DOC) concentration for more than 20 years. However, the sources of this DOC during base flow and hydrologic events remain unclear. The major objectives of this research were to identify sources of DOC during storm events and to explain the observed DOC-streamflow counterclockwise hysteresis during hydrologic events. Two main hypotheses to explain hysteresis during hydrologic events were tested: (1) distant headwater wetlands are the major DOC source, which lags behind peak flow due to travel time; and (2) the entire watershed contributes to the DOC at the gage, but the response of DOC lags behind the period when groundwater contributes most to streamflow. Sources of DOC were tracked using fluorescent dissolved organic matter (FDOM) sensors in surface water and groundwater wells. Wells were installed at four depths, 0.3, 0.6, 0.9, and 1.2 m, at four sites: a peaty low-gradient riparian area near the headwaters; a mid-hillslope area on a long hillslope mid-watershed; a near-stream area on a long hillslope mid-watershed; and a low-gradient tributary confluence area just above the gage. During storm events, FDOM and hydraulic head were measured at the nested groundwater wells. Samples for DOC analysis were also taken to determine the relationship between FDOM and DOC. Results suggest that both distant sources and the greater watershed played a role in the transport of DOC to the W-9 gage. Distant peaty sources dominated during large storms and contributed the highest surface water FDOM measurements. The peak FDOM at the gage was therefore best described as a result of transport. However, export from these distant sources terminated rapidly and did not explain continued elevated FDOM at the gage. Groundwater across the watershed exhibited hysteresis analogous to that in the stream itself, with FDOM peaking as head receded

  18. Carbon pools and flows during lab-scale degradation of old landfilled waste under different oxygen and water regimes

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted - Highlights: • 40 year old waste from an old MSW landfill was incubated in LSR experiments. • Carbon balances for anaerobic and aerobic waste degradation were established. • The transformation of carbon pools during waste degradation was investigated. • Waste aeration resulted in the formation of a new, stable organic carbon pool. • Water addition did not have a significant effect on aerobic waste degradation. - Abstract: Landfill aeration has been proven to accelerate the degradation of organic matter in landfills in comparison to anaerobic decomposition. The present study aims to evaluate pools of organic matter decomposing under aerobic and anaerobic conditions using landfill simulation reactors (LSR) filled with 40 year old waste from a former MSW landfill. The LSR were operated for 27 months, whereby the waste in one pair was kept under anaerobic conditions and the four other LSRs were aerated. Two of the aerated LSR were run with leachate recirculation and water addition and two without. The organic carbon in the solid waste was characterized at the beginning and at the end of the experiments and major carbon flows (e.g. TOC in leachate, gaseous CO2 and CH4) were monitored during operation. After the termination of the experiments, the waste from the anaerobic LSRs exhibited a long-term gas production potential of more than 20 NL kg−1 dry waste, which corresponded to the mineralization of around 12% of the initial TOC (67 g kg−1 dry waste). Compared to that, aeration led to threefold decrease in TOC (32–36% of the initial TOC were mineralized), without apparent differences in carbon discharge between the aerobic set ups with and without water addition. Based on the investigation of the carbon pools it could be demonstrated that a bit more than 10% of the initially present organic carbon was transformed into more recalcitrant forms, presumably due to the formation of humic substances. The source of anaerobic

  19. Carbon pools and flows during lab-scale degradation of old landfilled waste under different oxygen and water regimes

    Energy Technology Data Exchange (ETDEWEB)

    Brandstätter, Christian, E-mail: bran.chri@gmail.com; Laner, David, E-mail: david.laner@tuwien.ac.at; Fellner, Johann, E-mail: johann.fellner@tuwien.ac.at

    2015-06-15

    Graphical abstract: Display Omitted - Highlights: • 40 year old waste from an old MSW landfill was incubated in LSR experiments. • Carbon balances for anaerobic and aerobic waste degradation were established. • The transformation of carbon pools during waste degradation was investigated. • Waste aeration resulted in the formation of a new, stable organic carbon pool. • Water addition did not have a significant effect on aerobic waste degradation. - Abstract: Landfill aeration has been proven to accelerate the degradation of organic matter in landfills in comparison to anaerobic decomposition. The present study aims to evaluate pools of organic matter decomposing under aerobic and anaerobic conditions using landfill simulation reactors (LSR) filled with 40 year old waste from a former MSW landfill. The LSR were operated for 27 months, whereby the waste in one pair was kept under anaerobic conditions and the four other LSRs were aerated. Two of the aerated LSR were run with leachate recirculation and water addition and two without. The organic carbon in the solid waste was characterized at the beginning and at the end of the experiments and major carbon flows (e.g. TOC in leachate, gaseous CO{sub 2} and CH{sub 4}) were monitored during operation. After the termination of the experiments, the waste from the anaerobic LSRs exhibited a long-term gas production potential of more than 20 NL kg{sup −1} dry waste, which corresponded to the mineralization of around 12% of the initial TOC (67 g kg{sup −1} dry waste). Compared to that, aeration led to threefold decrease in TOC (32–36% of the initial TOC were mineralized), without apparent differences in carbon discharge between the aerobic set ups with and without water addition. Based on the investigation of the carbon pools it could be demonstrated that a bit more than 10% of the initially present organic carbon was transformed into more recalcitrant forms, presumably due to the formation of humic substances

  20. Primary carbon sources for juvenile penaeid shrimps in a mangrove-fringed Bay of Inhaca Island, Mozambique: a dual carbon and nitrogen isotope analysis.

    OpenAIRE

    Macia, A.

    2004-01-01

    A study to estimate the relative importance of mangrove primary carbon and nitrogen sources to five commercial penaeid shrimps species was done at Saco da Inhaca, a non-estuarine mangrove-fringed bay on Inhaca Island, southern Mozambique. Carbon and nitrogen stable isotope ratios were determined in a variety of primary producers (mangroves, epiphytes, phytoplankton and seagrasses), sediments and in five penaeid shrimp species (Penaeus (Fenneropenaeus) indicus, P. japonicus, P. semisulcatus, M...

  1. Synthesis of calcium hydroxyapatite from calcium carbonate and different orthophosphate sources: A comparative study

    International Nuclear Information System (INIS)

    Highlights: ► Calcium hydroxyapatite was synthesized from CaCO3 and four orthophosphates. ► Only H3PO4 led to the complete precipitation of orthophosphate species. ► H3PO4 was also the most efficient for calcium dissolution. ► Reaction pathway was dissolution-precipitation accompanied by agglomeration step. - Abstract: The synthesis of calcium hydroxyapatite (Ca-HA) starting from calcium carbonate and different orthophosphate sources, including orthophosphoric acid, potassium, sodium and ammonium dihydrogen orthophosphates, was investigated under ambient conditions. The reaction started with calcium carbonate dissolution in an acid medium, followed by rapid precipitation of calcium cations with orthophosphate species to form calcium phosphate based particles which were in the size range of 0.4–1 μm. These particles then agglomerated into much larger ones, up to 350 μm in diameter (aggregates). These aggregates possessed an unstable porous structure which was responsible for the porosity of the final products. The highest specific surface area and pore volume were obtained with potassium dihydrogen orthophosphate. On the other hand, orthophosphoric acid led to the highest dissolution of calcium carbonate and the complete precipitation of orthophosphate species. Under ambient conditions, calcium phosphate based solid products of low crystallinity were formed. Different intermediates were identified and a reaction pathway proposed.

  2. Source identification of polycyclic aromatic hydrocarbons in fine atmospheric particulates using stable carbon isotopic analysis

    International Nuclear Information System (INIS)

    In this paper, a method is established to quantitatively partition fractional contributions of polycyclic aromatic hydrocarbons (PAHs) in fine atmospheric particulate matters by using stable carbon isotopic analysis. Dichloromethane extraction, TLC purification, and gas chromatography-combustion system and isotope mass spectrometry (GC/C/IRMS), are used to measure the stable carbon isotope compositions (δ13C). The fractional contributions of coal combustion, vehicle exhaust and biomass burning to the PAHs in the fine particulate matters (PM2.5) collected in Jiading district, a suburb of Shanghai, are estimated. The results show that the δ13C values increase with decreasing molecular weight. The coal combustion and biomass burning play bigger role than vehicle exhaust in the PAHs, compared to the δ13C values of PAHs in all kinds of potential pollution sources. The estimated contributions from coal combustion,vehicle exhaust and biomass burning to PAHs of PM2.5 range from 3%- 21%, 29%- 33% and 46%- 67%, respectively, which agree well with the surrounding condition of the sampling site, indicating that it is feasible to estimate the fractional contributions of PAHs quantitatively by using stable carbon isotopic analysis. (authors)

  3. [Advanced nitrogen removal using innovative denitrification biofilter with sustained-release carbon source material].

    Science.gov (United States)

    Tang, Lei; Li, Peng; Zuo, Jian-e; Yuan, Lin; Li, Zai-xing

    2013-09-01

    An innovative denitrification biofilter was developed with polycaprolactone (PCL) as the carbon source and biofilm carrier. The performance of nitrogen removal was investigated with biologically treated effluent from secondary clarifier, and the results indicated that a maximum TN removal efficiency of 98.9% was achieved under the following conditions: influent total nitrogen (TN) concentration 30.0 mg x L(-1), denitrification load 54.0 mg (L x h)(-1), operating temperature 20. 1-22.0 degrees C, hydraulic retention time 0. 5 h; the total organic carbon (TOC) in effluent was 6.5-8.4 mg x L(-1), which was increased by 2.0-3.0 mg x L(-1) compared with that in the influent; the suspended solids (SS) concentration was less than 4.0 mg x L(-1) during operation; nearly 84.2% of the total released organic carbon which was used as electron donor in the denitrification process, was derived in the presence of microbes. The surface of the PCL pellets was observed by scanning electron microscope (SEM), it was shown that thick biofilm was formed on the surface of pellets, and the main microbial species were Bacillus and Trichobacteria. PMID:24289000

  4. A carbon cluster ion source for mass calibration at TRIGA-TRAP

    International Nuclear Information System (INIS)

    TRIGA-TRAP is a high-precision penning trap mass spectrometer installed at the research reactor TRIGA Mainz in order to determine the masses of short-lived fission products and - in addition to that - also the masses of actinide elements ranging from uranium up to californium. In order to determine precisely the masses of the nuclides of interest, the superconducting magnet providing the strong magnetic field for the Penning trap has to be calibrated by measuring the cyclotron frequency of an ion with well-known mass, which is, if possible, an isobaric nuclide of the ion of interest. Therefore, the best possible choice for mass calibration is to use carbon clusters as mass references, as demonstrated at the ISOLTRAP facility at ISOLDE/CERN. A laser ablation ion source for the production of carbon clusters has been developed using a frequency-doubled Nd:YAG laser. The design, current status, and results of the production of carbon cluster ions, using C60 and Sigradure registered samples, as well as other ions are presented

  5. Sources and metabolism of carbon in a Canadian boreal hydroelectric reservoir

    International Nuclear Information System (INIS)

    Using isotopic approaches, we try to document the sources and pathways of this CO2 with special attention to seasonal patterns and to the cycling of organic carbon in the reservoir Robert-Bourassa . It is located in the Boreal forest area, south-east of Hudson Bay and is part of a series of 8 reservoirs. It has a mean surface area of 2835 km2 and was flooded in 1979. The isotopic monitoring of the reservoir started in 1998. However, we will essentially refer here to data collected during the summers of 2001 and 2002. Three sampling strategies were retained: i) sampling in surface waters of 15 sites scattered across the reservoir, ii) sampling along three water columns (from shallow to deep sites), and iii) sampling of of inflow and outflow waters of the reservoir, once a month during 1 year. At each sampling site, in situ measurements included: water and air temperatures, pH, alkalinity and wind speed. Samples were collected at each site for the measurement of concentrations of dissolved organic carbon (DOC), C/N ratios of dissolved organic matter (DOM) and isotopic compositions of dissolved inorganic carbon (DIC), DOC, air CO2 and dissolved organic nitrogen (DON)

  6. Influence of carbon and lipid sources on variation of mercury and other trace elements in polar bears (Ursus maritimus).

    Science.gov (United States)

    Routti, Heli; Letcher, Robert J; Born, Erik W; Branigan, Marsha; Dietz, Rune; Evans, Thomas J; McKinney, Melissa A; Peacock, Elizabeth; Sonne, Christian

    2012-12-01

    In the present study, the authors investigated the influence of carbon and lipid sources on regional differences in liver trace element (As, Cd, Cu, total Hg, Mn, Pb, Rb, Se, and Zn) concentrations measured in polar bears (Ursus maritimus) (n = 121) from 10 Alaskan, Canadian Arctic, and East Greenland subpopulations. Carbon and lipid sources were assessed using δ(13) C in muscle tissue and fatty acid (FA) profiles in subcutaneous adipose tissue as chemical tracers. A negative relationship between total Hg and δ(13) C suggested that polar bears feeding in areas with higher riverine inputs of terrestrial carbon accumulate more Hg than bears feeding in areas with lower freshwater input. Mercury concentrations were also positively related to the FA 20:1n-9, which is biosynthesized in large amounts in Calanus copepods. This result raises the hypothesis that Calanus glacialis are an important link in the uptake of Hg in the marine food web and ultimately in polar bears. Unadjusted total Hg, Se, and As concentrations showed greater geographical variation among polar bear subpopulations compared with concentrations adjusted for carbon and lipid sources. The Hg concentrations adjusted for carbon and lipid sources in Bering-Chukchi Sea polar bear liver tissue remained the lowest among subpopulations. Based on these findings, the authors suggest that carbon and lipid sources for polar bears should be taken into account when one is assessing spatial and temporal trends of long-range transported trace elements. PMID:22987581

  7. Development of a stationary chest tomosynthesis system using carbon nanotube x-ray source array

    Science.gov (United States)

    Shan, Jing

    X-ray imaging system has shown its usefulness for providing quick and easy access of imaging in both clinic settings and emergency situations. It greatly improves the workflow in hospitals. However, the conventional radiography systems, lacks 3D information in the images. The tissue overlapping issue in the 2D projection image result in low sensitivity and specificity. Both computed tomography and digital tomosynthesis, the two conventional 3D imaging modalities, requires a complex gantry to mechanically translate the x-ray source to various positions. Over the past decade, our research group has developed a carbon nanotube (CNT) based x-ray source technology. The CNT x-ray sources allows compacting multiple x-ray sources into a single x-ray tube. Each individual x-ray source in the source array can be electronically switched. This technology allows development of stationary tomographic imaging modalities without any complex mechanical gantries. The goal of this work is to develop a stationary digital chest tomosynthesis (s-DCT) system, and implement it for a clinical trial. The feasibility of s-DCT was investigated. It is found that the CNT source array can provide sufficient x-ray output for chest imaging. Phantom images have shown comparable image qualities as conventional DCT. The s-DBT system was then used to study the effects of source array configurations and tomosynthesis image quality, and the feasibility of a physiological gated s-DCT. Using physical measures for spatial resolution, the 2D source configuration was shown to have improved depth resolution and comparable in-plane resolution. The prospective gated tomosynthesis images have shown substantially reduction of image blur associated with lung motions. The system was also used to investigate the feasibility of using s-DCT as a diagnosis and monitoring tools for cystic fibrosis patients. A new scatter reduction methods for s-DCT was also studied. Finally, a s-DCT system was constructed by

  8. Stationary chest tomosynthesis using a carbon nanotube x-ray source array: a feasibility study

    Science.gov (United States)

    Shan, Jing; Tucker, Andrew W.; Lee, Yueh Z.; Heath, Michael D.; Wang, Xiaohui; Foos, David H.; Lu, Jianping; Zhou, Otto

    2015-01-01

    Chest tomosynthesis is a low-dose, quasi-3D imaging modality that has been demonstrated to improve the detection sensitivity for small lung nodules, compared to 2D chest radiography. The purpose of this study is to investigate the feasibility and system requirements of stationary chest tomosynthesis (s-DCT) using a spatially distributed carbon nanotube (CNT) x-ray source array, where the projection images are collected by electronically activating individual x-ray focal spots in the source array without mechanical motion of the x-ray source, detector, or the patient. A bench-top system was constructed using an existing CNT field emission source array and a flat panel detector. The tube output, beam quality, focal spot size, system in-plane and in-depth resolution were characterized. Tomosynthesis slices of an anthropomorphic chest phantom were reconstructed for image quality assessment. All 75 CNT sources in the source array were shown to operate reliably at 80 kVp and 5 mA tube current. Source-to-source consistency in the tube current and focal spot size was observed. The incident air kerma reading per mAs was measured as 74.47 uGy mAs-1 at 100 cm. The first half value layer of the beam was 3 mm aluminum. An average focal spot size of 2.5  ×  0.5 mm was measured. The system MTF was measured to be 1.7 cycles mm-1 along the scanning direction, and 3.4 cycles mm-1 perpendicular to the scanning direction. As the angular coverage of 11.6°-34°, the full width at half maximum of the artifact spread function improved greatly from 9.5 to 5.2 mm. The reconstructed tomosynthesis slices clearly show airways and pulmonary vascular structures in the anthropomorphic lung phantom. The results show the CNT source array is capable of generating sufficient dose for chest tomosynthesis imaging. The results obtained so far suggest an s-DCT using a distributed CNT x-ray source array is feasible.

  9. Colored dissolved organic matter in shallow estuaries: relationships between carbon sources and light attenuation

    Science.gov (United States)

    Oestreich, W. K.; Ganju, N. K.; Pohlman, J. W.; Suttles, S. E.

    2016-02-01

    Light availability is of primary importance to the ecological function of shallow estuaries. For example, benthic primary production by submerged aquatic vegetation is contingent upon light penetration to the seabed. A major component that attenuates light in estuaries is colored dissolved organic matter (CDOM). CDOM is often measured via a proxy, fluorescing dissolved organic matter (fDOM), due to the ease of in situ fDOM sensor measurements. Fluorescence must be converted to CDOM absorbance for use in light attenuation calculations. However, this CDOM-fDOM relationship varies among and within estuaries. We quantified the variability in this relationship within three estuaries along the mid-Atlantic margin of the eastern United States: West Falmouth Harbor (MA), Barnegat Bay (NJ), and Chincoteague Bay (MD/VA). Land use surrounding these estuaries ranges from urban to developed, with varying sources of nutrients and organic matter. Measurements of fDOM (excitation and emission wavelengths of 365 nm (±5 nm) and 460 nm (±40 nm), respectively) and CDOM absorbance were taken along a terrestrial-to-marine gradient in all three estuaries. The ratio of the absorption coefficient at 340 nm (m-1) to fDOM (QSU) was higher in West Falmouth Harbor (1.22) than in Barnegat Bay (0.22) and Chincoteague Bay (0.17). The CDOM : fDOM absorption ratio was variable between sites within West Falmouth Harbor and Barnegat Bay, but consistent between sites within Chincoteague Bay. Stable carbon isotope analysis for constraining the source of dissolved organic matter (DOM) in West Falmouth Harbor and Barnegat Bay yielded δ13C values ranging from -19.7 to -26.1 ‰ and -20.8 to -26.7 ‰, respectively. Concentration and stable carbon isotope mixing models of DOC (dissolved organic carbon) indicate a contribution of 13C-enriched DOC in the estuaries. The most likely source of 13C-enriched DOC for the systems we investigated is Spartina cordgrass. Comparison of DOC source to CDOM : f

  10. Sources and Transformations of Carbon and Nitrogen in the Potomac River Estuary

    Science.gov (United States)

    Pennino, M. J.; Kaushal, S.; Murthy, S.

    2011-12-01

    Urbanization has altered the transport of nitrogen (N) and carbon (C) in river ecosystems, making it important to understand how rivers are responding to these increased inputs of C and N. This study examines the capacity of a major tributary of the Chesapeake Bay, the Potomac River, to transform N and C inputs from the world's largest advanced wastewater treatment facility (Washington D.C. Water and Sewer Authority). Surface water and effluent samples were collected monthly for one year, along longitudinal transects of the Potomac River. Water samples were analyzed for the major dissolved and particulate forms of C and N. Nitrate stable isotopes were used to trace the fate of wastewater nitrate, as well as how other nitrate sources vary downriver. Sources of carbon downriver were traced using fluorescence spectroscopy, excitation emission matrices (EEMs), and PARAFAC modeling. Historical influent and effluent data on C and N levels were also compared with regional population growth data, climate change data, and long-term interannual records of C and N levels within downstream stations along the Potomac River. Improvements in treatment technology over the past two decades have shown significant decreases in effluent nitrogen levels, with corresponding decreases overtime of nutrients at downstream sampling stations. Levels of nitrate show increases within the vicinity of the wastewater treatment outfall, but decrease rapidly downstream, potentially indicating nutrient uptake and/or denitrification. Total organic carbon levels show a smaller decrease downstream, resulting in an increase in the C:N ratio downstream. Longitudinal river chemistry data also show that dissolved inorganic nitrogen goes down while total organic nitrogen goes up with distance downriver, indicating biological transformations are taking place along the river. Preliminary data from fluorescence EEMs suggested that more humic-like organic matter is important above the wastewater treatment plant

  11. Functional Stability Of A Mixed Microbial Consortia Producing PHA From Waste Carbon Sources

    Energy Technology Data Exchange (ETDEWEB)

    David N. Thompson; Erik R. Coats; William A. Smith; Frank J. Loge; Michael P. Wolcott

    2006-04-01

    Polyhydroxyalkanoates (PHAs), naturally-occurring biological polyesters that are microbially synthesized from a myriad of carbon sources, can be utilized as biodegradable substitutes for petroleum-derived thermoplastics. However, current PHA commercialization schemes are limited by high feedstock costs, the requirement for aseptic reactors, and high separation and purification costs. Bacteria indigenous to municipal waste streams can accumulate large quantities of PHA under environmentally controlled conditions; hence, a potentially more environmentally-effective method of production would utilize these consortia to produce PHAs from inexpensive waste carbon sources. In this study, PHA production was accomplished in sequencing batch bioreactors utilizing mixed microbial consortia from municipal activated sludge as inoculum, in cultures grown on real wastewaters. PHA production averaged 85%, 53%, and 10% of the cell dry weight from methanol-enriched pulp-and-paper mill foul condensate, fermented municipal primary solids, and biodiesel wastewater, respectively. The PHA-producing microbial consortia were examined to explore the microbial community changes that occurred during reactor operations, employing denaturing gradient gel electrophoresis (DGGE) of 16S-rDNA from PCR-amplified DNA extracts. Distinctly different communities were observed both between and within wastewaters following enrichment. More importantly, stable functions were maintained despite the differing and contrasting microbial populations.

  12. Transcriptional profiling of biomass degradation-related genes during Trichoderma reesei growth on different carbon sources.

    Science.gov (United States)

    Chen, Xiuzhen; Luo, Yingfeng; Yu, Hongtao; Sun, Yuhui; Wu, Hong; Song, Shuhui; Hu, Songnian; Dong, Zhiyang

    2014-03-10

    To identify all the gene products involved in cellulosic biomass degradation, we employed RNA sequencing technology to perform a genome-wide comparison of gene expression during growth of Trichoderma reesei QM9414 on cellulose or glucose. Due to their important role in lignocellulose decomposition, we focused on CAZymes and other secreted proteins. In total, 122 CAZymes showed at least a two-fold change in mRNA abundance, and 97 of those were highly induced by cellulose. Compared to the well-characterized cellulases and hemicellulases, a majority of the other upregulated CAZymes showed lower transcriptional levels. In addition, 64 secreted proteins, including oxidoreductases, exhibited at least two-fold upregulation on cellulose medium. To better understand the potential roles of low-abundance CAZymes in cellulose breakdown, we compared the expression patterns of 25 glycoside hydrolase genes under different conditions via real-time PCR. Substantial differences for the 25 genes were observed for individual strains grown on different carbon sources, and between QM9414 and RUTC30 when grown on the same carbon source. Moreover, we identified 3 genes that are coregulated with known cellulases. Collectively, this study highlights a comprehensive transcriptional profile for biomass degradation-related proteins and provides a first step toward the identification of candidates to construct optimized enzyme cocktails. PMID:24445169

  13. Thermal simulation experiment on the hydrocarbon regeneration of marine carbonate source rock

    Institute of Scientific and Technical Information of China (English)

    LI HuiLi; JIN ZhiJun; HE ZhiLiang; QIN JianZhong; SHAO ZhiBing

    2007-01-01

    Hydrocarbon regeneration of marine carbonate source rock was simulated with thermal experiments in a laboratory. The results reveal that hydrocarbon regeneration does not simply continue the primary hydrocarbon generation process, and that, for marine carbonate source rock, discontinuous hydrocarbon generation differs greatly from the continuous generation. Several different features of hydrocarbon regeneration were observed in the experiments. First, the liquid hydrocarbon generation peak was always observed no matter what the initial maturity of the sample was. Moreover, the maturity and the liquid hydrocarbon yield corresponding to the peak varied with the sample's initial maturity. Second, the hydrocarbon regeneration started earlier than the continuous one. In the experiments, the hydrocarbon could be re-generated when the sample maturity did not rise to any great extent. Third, the accumulative hydrocarbon-generating quantity during discontinuous generation was always more than that during continuous generation. And the hydrocarbon-generating quantity varied with the discontinuous generation history. Chemical kinetic analysis suggests that discontinuous hydrocarbon generation should not only be explained by the parallel reaction mechanism but also by the consecutive reaction mechanism which has been ignored in the traditional chemical kinetic model for continuous hydrocarbon generation.

  14. Polygalacturonases from Moniliophthora perniciosa are regulated by fermentable carbon sources and possible post-translational modifications.

    Science.gov (United States)

    Argôlo Santos Carvalho, Heliana; de Andrade Silva, Edson Mario; Carvalho Santos, Stenio; Micheli, Fabienne

    2013-11-01

    We report the first molecular and in silico analysis of Monilophthora perniciosa polygalacturonases (PGs). Three MpPG genes (MpPG1, MpPG2 and MpPG3) were identified and analyzed at transcriptional level, by RT-qPCR, in dikaryotic M. perniciosa mycelium grown on solid-bran based medium and on liquid medium supplemented with different fermentable and non-fermentable carbon sources. The MpPG genes presented different expression patterns suggesting different individual regulation. However, all are mainly regulated by fermentable carbon sources (galactose and mannose). The integrated analysis of PG gene expression and systems biology (using MpG1 and MpG2 orthologs in Neurospora crassa, named NCU06961 and NCU02369, respectively) allowed identifying some possible mechanism of protein regulation during the necrotrophic fungal phase. MpPG1-NCU06961 and MpPG2-NCU02369 directly or indirectly interacted with central and highly connected proteins involved in protein synthesis and protein regulation associated to post-translational modifications, in cell wall metabolism, and in cellular metabolism related to energy production. This analysis also allowed the identification of key proteins for further studies of M. perniciosa development and/or for disease management, such as MpPG2, a pectin methylesterase, an acetolactate synthase and the small ubiquitin-like modifier SMT3-like. PMID:24140149

  15. Diamondlike carbon deposition on plastic films by plasma source ion implantation

    International Nuclear Information System (INIS)

    Application of pulsed high negative voltage (∼10 μs pulse width, 300-900 pulses per second) to a substrate is found to induce discharge, thereby increasing ion current with an inductively coupled plasma source. This plasma source ion beam implantation (PSII) technique is investigated for the pretreatment and deposition of diamond-like carbon (DLC) thin layer on polyethylene terepthalate (PET) film. Pretreatment of PET with N2 and Ar plasma is expected to provide added barrier effects when coupled with DLC deposition, with possible application to fabrication of PET beverage bottles. PSII treatment using N2 and Ar in separate stages is found to change the color of the PET film, effectively increasing near-ultraviolet absorption. The effects of this pretreatment on the chemical bonding of C, H, and O are examined by x-ray photoelectron spectroscopy (XPS). DLC thin film was successfully deposited on the PET film. The surface of the DLC thin layer is observed to be smooth by scanning electron microscopy, and its structure characteristics are examined by XPS and laser Raman spectroscopy. Subsequent processing using acetylene or acetylene and Ar (20%) produced thin carbon layers that are confirmed to be graphite-dominated DLC. Also, this PSII method is employed in order to deposit the DLC layer on the inside surface of the PET bottle and to reduce oxygen permeation rate by 40%

  16. Diamondlike carbon deposition on plastic films by plasma source ion implantation

    Science.gov (United States)

    Tanaka, T.; Yoshida, M.; Shinohara, M.; Takagi, T.

    2002-05-01

    Application of pulsed high negative voltage (~10 μs pulse width, 300-900 pulses per second) to a substrate is found to induce discharge, thereby increasing ion current with an inductively coupled plasma source. This plasma source ion beam implantation (PSII) technique is investigated for the pretreatment and deposition of diamond-like carbon (DLC) thin layer on polyethylene terepthalate (PET) film. Pretreatment of PET with N2 and Ar plasma is expected to provide added barrier effects when coupled with DLC deposition, with possible application to fabrication of PET beverage bottles. PSII treatment using N2 and Ar in separate stages is found to change the color of the PET film, effectively increasing near-ultraviolet absorption. The effects of this pretreatment on the chemical bonding of C, H, and O are examined by x-ray photoelectron spectroscopy (XPS). DLC thin film was successfully deposited on the PET film. The surface of the DLC thin layer is observed to be smooth by scanning electron microscopy, and its structure characteristics are examined by XPS and laser Raman spectroscopy. Subsequent processing using acetylene or acetylene and Ar (20%) produced thin carbon layers that are confirmed to be graphite-dominated DLC. Also, this PSII method is employed in order to deposit the DLC layer on the inside surface of the PET bottle and to reduce oxygen permeation rate by 40%.

  17. Reduction of nitrous oxide emissions from partial nitrification process by using innovative carbon source (mannitol).

    Science.gov (United States)

    Zhang, Xinwen; Wang, Xiaoqing; Zhang, Jian; Huang, Xiaoyu; Wei, Dong; Lan, Wei; Hu, Zhen

    2016-10-01

    The purpose of this study was to evaluate the effect of mannitol as carbon source on nitrogen removal and nitrous oxide (N2O) emission during partial nitrification (PN) process. Laboratory-scale PN sequencing batch reactors (SBRs) were operated with mannitol and sodium acetate as carbon sources, respectively. Results showed that mannitol could remarkably reduce N2O-N emission by 41.03%, without influencing the removal efficiency of NH4(+)-N. However, it has a significant influence on nitrite accumulation ratio (NAR) and TN removal, which were 19.97% and 13.59% lower than that in PN with sodium acetate, respectively. Microbial analysis showed that the introduction of mannitol could increase the abundance of bacteria encoding nosZ genes. In addition, anti-oxidant enzymes (T-SOD, POD and CAT) activities were significantly reduced and the dehydrogenase activity had an obvious increase in mannitol system, indicating that mannitol could alleviate the inhibition of N2O reductase (N2OR) activities caused by high NO2(-)-N concentration. PMID:27423546

  18. Monitoring of black carbon concentration at an inland rural area including fixed sources in Korea.

    Science.gov (United States)

    Lee, Jeonghoon; Yun, Jeongseok; Kim, Kyeong Jun

    2016-01-01

    We monitored black carbon (BC) concentration for 6months to understand the characteristics of atmospheric aerosols of an inland rural area in Korea. A multi-angle absorption photometer was used to continuously monitor the BC concentration, which was compared with elemental carbon (EC) concentration measured by an OC/EC Analyzer. For the atmospheric aerosols less than 10μm, size distributions were measured using both an optical particle counter and a scanning mobility particle sizer. The diurnal variations for BC concentration show that the average BC concentration was 1.43μgm(-3) and exhibited peaks in the morning rush hours. However, the BC concentration measured at night from 20:00 to 08:00 was higher than that measured during the day. The reason why the BC concentration at night was higher would be partly due to the regional characteristics influenced by the combination of local fixed sources and traffic condition. It is suggested that the traffic and transporting of pollutants from the west influenced the increase in the BC concentration at inland rural area including fixed sources. PMID:25900115

  19. Influence of carbon source and temperature on the denitrifying phosphorus removal process

    Institute of Scientific and Technical Information of China (English)

    WANG Yayi; WANG Shuying; PENG Yongzhen; Zhu Guibing; LING Yunfang

    2007-01-01

    To supply the valuable operating parameters for the popular usage of the new denitrifying phosphors removal process,it is essential to study the dominant biochemical reactions and the characteristics of denitriflying phosphorus removing bacteria(DPB).Thus,parallel batch experiments using DPB sludge were carried out to assess the effect of substrates(sewage,HAc,and endogenous carbon source)on denitriflying dephosphorus removal efficiency in this study.The results showed that the initial specific phosphorus release rate increased with the high concentration of the short-chain volatile fatty acids ratio in the influent,and sufficient phosphorus was released by DPB.This improved the subsequent denitrification and phosphorus uptake efficiency.The specific endogenous denitrification mainly relies on the internal carbon source(PHB)stored by poly-P bacteria.Denitrifying phosphorus removing bacteria were very hungry when the internal PHB was consumed.Consequently,the specific endogenous denitrification rate was low and the phosphorus uptake did not happen.On the other hand,in the experiment,the denitrifying phosphorus removal performance under two temperature conditions(8-10℃ and 25-26℃)was also investigated and analyzed.It was found that the lower temperature decreased the specific phosphorus release and uptake rate,but did not inhibit the denitrifying phosphorus removal completely.Therefore,the negative influence of the low temperature on the overall phosphorus removal was not significant.

  20. Effect of carbon source and nitrate concentration on denitrifying phosphorus removal by DPB sludge

    Institute of Scientific and Technical Information of China (English)

    WANG Ya-yi; PENG Yong-zhen; Wang Shu-ying; PAN Mian-li

    2004-01-01

    Effect of added carbon source and nitrate concentration on the denitrifying phosphorus removal by DPB sludge was systematically studied using batch experiments, at the same time the variation of ORP was investigated.Results showed that the denitrifying and phosphorus uptake rate in anoxic phase increased with the high initial anaerobic carbon source addition. However once the initial COD concentration reached a certain level, which was in excess to the PHB saturation of poly-P bacteria, residual COD carried over to anoxic phase inhibited the subsequent denitrifying phosphorus uptake. Simultaneously, phosphate uptake continued until all nitrate was removed, following a slow endogenous release of phosphate. High nitrate concentration in anoxic phase increased the initial denitrifying phosphorus rate. Once the nitrate was exhausted, phosphate uptake changed to release. Moreover, the time of this turning point occurred later with the higher nitrate addition. On the other hand, through on-line monitoring the variation of the ORP with different initial COD concentration , it was found ORP could be used as a control parameter for phosphorus release, but it is impossible to utilize ORP for controlling the denitrificaion and anoxic phosphorus uptake operations.

  1. Xylanase Production by Bacillus circulans D1 Using Maltose as Carbon Source

    Science.gov (United States)

    Bocchini, D. A.; Gomes, E.; da Silva, R.

    Bacillus circulans D1 is a good producer of extracellular thermostable xylanase. Xylanase production in different carbon sources was evaluated and the enzyme synthesis was induced by various carbon sources. It was found that d-maltose is the best inducer of the enzyme synthesis (7.05 U/mg dry biomass at 48 h), while d-glucose and d-arabinose lead to the production of basal levels of xylanase. The crude enzyme solution is free of cellulases, even when the microorganism was cultivated in a medium with d-cellobiose. When oat spelt xylan was supplemented with d-glucose, the repressive effect of this sugar on xylanase production was observed at 24 h, only when used at 5.0 g/L, leading to a reduction of 60% on the enzyme production. On the other hand, when the xylan medium was supplemented with d-xylose (3.0 or 5.0 g/L), this effect was more evident (80 and 90% of reduction on the enzyme production, respectively). Unlike that observed in the xylan medium, glucose repressed xylanase production in the maltose medium, leading to a reduction of 55% on the enzyme production at 24 h of cultivation. Xylose, at 1.0 g/L, induced xylanase production on the maltose medium. On this medium, the repressive effect of xylose, at 3.0 or 5.0 g/L, was less expressive when compared to its effect on the xylan medium.

  2. Effective pine bark composting with the Dome Aeration Technology

    International Nuclear Information System (INIS)

    In South Africa garden refuse is primarily disposed of in domestic landfills. Due to the large quantities generated, any form of treatment would be beneficial for volume reduction, waste stabilization and resource recovery. Dome Aeration Technology (DAT) is an advanced process for aerobic biological degradation of garden refuse and general waste [Paar, S., Brummack, J., Gemende, B., 1999a. Advantages of dome aeration in mechanical-biological waste treatment. In: Proceedings of the 7th International Waste Management and Landfill Symposium, Cagliari, 4-8 October 1999; Paar, S., Brummack, J., Gemende, B., 1999b. Mechanical-biological waste stabilization by the dome aeration method. Environment Protection Engineering 25 (3/99). Mollekopf, N., Brummack, J., Paar, S., Vorster, K., 2002. Use of the Dome Aeration Technology for biochemical stabilization of waste prior to landfilling. In: Proceedings of the Wastecon 2002, Waste Congress and Exhibition, Durban, South Africa.]. It is a non-reactor open windrow composting process, with the main advantage being that the input material needs no periodic turning. A rotting time of only 3-4 months indicates the high efficiency. Additionally, the low capital/operational costs, low energy inputs and limited plant requirements provide potential for use in aerobic refuse stabilization. The innovation in the DAT process is the passive aeration achieved by thermally driven advection through open windrows caused by temperature differences between the degrading material and the outside environment. This paper investigates the application of Dome Aeration Technology to pine bark composting as part of an integrated waste management strategy. A full-scale field experiment was performed at the Bisasar Road Landfill Site in Durban to assess the influence of climate, waste composition and operational conditions on the process. A test windrow was constructed and measurements of temperature and airflow through the material were taken. The process

  3. Electron optics simulation for designing carbon nanotube based field emission x-ray source

    Science.gov (United States)

    Sultana, Shabana

    In this dissertation, electron optics simulation for designing carbon nanotube (CNT) based field emission x-ray source for medical imaging applications will be presented. However, for design optimization of x-ray tubes accurate electron beam optics simulation is essential. To facilitate design of CNT x-ray sources a commercial 3D finite element software has been chosen for extensive simulation. The results show that a simplified model of uniform electron field emission from the cathode surface is not sufficient when compared to experimental measurements. This necessitated the development of a refined model to describe a macroscopic field emission CNT cathode for electron beam optics simulations. The model emulates the random distribution of CNTs and the associated variation of local field enhancement factor. The main parameter of the model has been derived empirically from the experimentally measured I-V characteristics of the CNT cathode. Simulation results based on this model agree well with experiments which include measurements of the transmission rate and focus spot size. The model provides a consistent simulation platform for optimization of electron beam optics in CNT x-ray source design. A systematic study of electron beam optics in CNT x-ray tubes led to the development of a new generation of compact x-ray source with multiple pixels. A micro focus field emission x-ray source with a variable focal spot size has been fully characterized and evaluated. It has been built and successfully integrated into micro-CT scanners which are capable of dynamic cardiac imaging of free-breathing small animals with high spatial and temporal resolutions. In addition a spatially distributed high power multi-beam x-ray source has also been designed and integrated into a stationary digital breast tomosynthesis (s-DBT) configuration. This system has the potential to reduce the total scan time to 4 seconds and yield superior image quality in breast imaging.

  4. Constraining carbon sources and cycling of endolithic microbial communities in the Atacama Desert

    Science.gov (United States)

    Ziolkowski, L. A.; Slater, G. F.; Davila, A.; Wierzchos, J.

    2010-12-01

    The Atacama Desert, one of the driest places on Earth, is considered a suitable analog for the extremely arid, oxidizing conditions on the surface of Mars. Recent observations suggest the presence of evaporitic deposits on the surface of Mars, such as those found in the Atacama. Halites in the Atacama have been shown to be hygroscopic and are colonized by photosynthetic microbes. While there is considerable evidence for the decrease in abundance and diversity of microbes closer to the hyper-arid core of the Atacama, experimental studies have thus far have yet to estimate the sources of carbon to these communities and the rate at which they cycle. To address these questions, we characterized the isotopic composition (13C and 14C) microbial community biomarkers from four distinct sites in the Atacama. Sites ranged from halites in the hyper-arid core (Yungay, Salar Grande) to volcanic rock and gypsum near the Monturaqui Crater. Our analysis of the phospholipids fatty acids (PLFA) and glycolipid fatty acid (GLFA) methyl esters of the endoliths agreed with previous studies: the abundance and diversity of microbes decreases approaching the hyper-arid core. The total PLFA and GLFA concentrations were lower at Yungay than Salar Grande and higher in the gypsum and volcanic rock samples. Changes in the mole percentage distribution of the PLFA and GLFA illustrated that the endolithic communities inhabiting the volcanic rock and gypsum were more complex than those inhabiting the halites. ∂13C of both PLFA and GLFA showed that non-halite lipids were less depleted in 13C than halite-lipids. This suggested a difference in carbon source or cycling. The 14C content of PLFA and GLFA varied by up to 250 per mil. Endolith PLFA and GLFA from the gypsum had radiocarbon signatures comparable to the modern atmosphere, which suggests that the predominant source of carbon to the system is the modern atmosphere and that lipids are cycling rapidly in this system. However, at the other three

  5. The Efficiency of Iron and Manganese Removal from Groundwater Using Tower Aeration

    Directory of Open Access Journals (Sweden)

    Meghdad Pirsaheb

    2012-09-01

    Full Text Available Groundwaters passing through different layers of soil and due to its water properties and its high solubility, contain elements and minerals of material in the soil that sometimes can be dangerous for the health of consumers or at least undesirable in terms of cognitive beautiful. Iron and manganese are from constitutive of the soil and rocks of the Earth's surface. Water penetration through soil and rock can minerals such as these elements have dissolved and bring them into solution. The problems of iron and manganese in groundwater in domestic installations, commercial, industrial and refineries are created, and because much of the community water supply from underground water supplies will be removed where iron and manganese concentrations exceeded it is necessary. In this study Tower aeration system performance for the removal of iron and manganese from groundwater sources have been studied. In this research, pilot column aeration tower design, implementation and was established. This system made of PVC with a diameter and height 150 cm and 15 cm which was filled with flexible pipe parts. The initial pH=5, 7 and 9 and the initial concentration of Fe and Mn 2, 3 and 4 mg/l of the output system, sampling was done.

  6. Removal of diclofenac from surface water by electron beam irradiation combined with a biological aerated filter

    Science.gov (United States)

    He, Shijun; Wang, Jianlong; Ye, Longfei; Zhang, Youxue; Yu, Jiang

    2014-12-01

    The degradation of DCF was investigated in aqueous solution by using electron beam (EB) technology. When the initial concentration was between 10 and 40 mg/L, almost 100% of the DCF was degraded at a dose of 0.5 kGy. However, only about 6.5% of DCF was mineralized even at 2 kGy according to total organic carbon (TOC) measurements. A combined process of EB and biological aerated filter (BAF) was therefore developed to enhance the treatment of DCF contaminated surface water. The effluent quality of combined process was substantially improved by EB pretreatment due to the degradation of DCF and related intermediates. Both irradiation and biological treatment reduced the toxicity of the treated water. The experimental results showed that EB is effective for removing DCF from artificial aqueous solution and real surface water.

  7. Novel ferulic acid esterases from Bifidobacterium sp. produced on selected synthetic and natural carbon sources

    Directory of Open Access Journals (Sweden)

    Dominik Szwajgier

    2010-09-01

    Full Text Available Background. Ferulic acid esterases (or feruloyl esterases, a common group of hydrolases are very well distributed in the plant kongdom. The fungal feruloyl esterases were very extensively studied whereas probiotic lactic acid bacteria as the source of this enzyme were generally omitted. Free phenolic acids – strong antioxidants can be released from the dietary fiber by the action of intestinal lactic acid bacteria. The aim of this study was to examine the three probiotic Bifidobacterium strains to produce extracellular FAE on different synthetic and natural carbon sources. Material and methods. Studies were carried out using Bifidibacteriumstrains (B. animalis Bi30, B. catenulatum KD 14 and B. longum KN 29. The strains were cultivated using minimal growth media containing selected natural and synthetic carbon sources: German wheat bran, rye bran, barley spent grain, isolated larchwood arabinogalactan, apple pectin, corn pectin, methyl esters of phenolic acids. The production of extracellular feruloyl esterase was estimated using the post cultivation supernatants and methyl ferulate. The concentration of ferulic acid released from the ester was determined using HPLC with DAD detection. Results. The most efficient bacterial strain for FAE production was B. animalis cultivated in the presence of methyl p-coumarate and methyl ferulate as the main carbon sources (14.95 nmol·ml-1·min-1 and 4.38 nmol·ml-1·min-1, respectively. In the case of each FAE, the highest activity was obtained at 37oC (pH 6.3 in Theorell/Steinhagen buffer (B. animalis Bi30 or in Tris/HCl buffer (B. catenulatum KD14 and B. longum KN29. Taking under consideration all results, it should be noticed that the highest feruloyl esterase activities were obtained using synthetic methyl esters of phenolic acids. Conclusions. The presented resultsbroaden the knowledgeabout the production of the feruloyl esterase by probiotic bacteria. Although the enzyme is only accessory during

  8. Dietary carbon sources of mussels and tubeworms from Galapagos hydrothermal vents determined from tissue 14C activity

    International Nuclear Information System (INIS)

    The results of an investigation of the dietary carbon sources of mussels and tubeworms from Galapagos hydrothermal vents, using data from 14C and 13C/12C ratio measurements in tissues, are reported. It is shown that: (1) filter-feeding organisms in the vent system are directly or indirectly incorporating 'dead' carbon of magmatic origin into their tissues; (2) approximately 25% or less of the dietary carbon available to the mussels is from sedimenting particulate organic carbon fixed photosynthetically at the surface; and (3) mussel tissue is incorporating relatively more 'dead' dissolved inorganic carbon than is mussel shell carbonate in specimens collected at the same location near the vent. (U.K.)

  9. Thermal Conductivity of Single-Walled Carbon Nanotube with Internal Heat Source Studied by Molecular Dynamics Simulation

    Science.gov (United States)

    Li, Yuan-Wei; Cao, Bing-Yang

    2013-12-01

    The thermal conductivity of (5, 5) single-walled carbon nanotubes (SWNTs) with an internal heat source is investigated by using nonequilibrium molecular dynamics (NEMD) simulation incorporating uniform heat source and heat source-and-sink schemes. Compared with SWNTs without an internal heat source, i.e., by a fixed-temperature difference scheme, the thermal conductivity of SWNTs with an internal heat source is much lower, by as much as half in some cases, though it still increases with an increase of the tube length. Based on the theory of phonon dynamics, a function called the phonon free path distribution is defined to develop a simple one-dimensional heat conduction model considering an internal heat source, which can explain diffusive-ballistic heat transport in carbon nanotubes well.

  10. Radon removal from water supplies by diffused bubble aeration system

    International Nuclear Information System (INIS)

    The removal efficiency of moderate levels of radon from groundwater supplies was evaluated using the diffused bubble aeration technique. An aeration system was designed, constructed and operated for that purpose. The effect of air-to-water ratio and detention time on radon removal were evaluated through 32 runs. The possibility to reduce the radon activity in the influent stream to the U.S. Environmental Protection Agency proposed maximum contaminant level (MCL) was verified through many alternative combined values of both air-to-water ratios and detention times. The results showed that at detention time of 19 minutes and air-to-water ratio of 12, the average radon removal is about 97%. The stripping constant characterizing this system was calculated and the removal efficiency at extended values of detention time was predicted. The data obtained are site specific, being dependent on container size, type of diffusers, temperature, and influent radon radioactivity. (author)

  11. Feasibility of biological aerated filters (BAFs) for treating landfill leachate.

    OpenAIRE

    Stephenson, Tom; Pollard, Simon J. T.; Cartmell, Elise

    2004-01-01

    Ammonia can be removed from landfill leachate through aerobic biological processes. The biological aerated filter (BAF) combines biological treatment and subsequent biomass separation in one reactor providing a small footprint alternative to conventional systems. Leachate from an operational landfill was found to be aerobically treatable using the OECD recommended Modified Zahn- Wellens test. This leachate was used as feed to a pilot-scale BAF at influent COD and ammoniacal-...

  12. Landfill aeration for emission control before and during landfill mining.

    Science.gov (United States)

    Raga, Roberto; Cossu, Raffaello; Heerenklage, Joern; Pivato, Alberto; Ritzkowski, Marco

    2015-12-01

    The landfill of Modena, in northern Italy, is now crossed by the new high velocity railway line connecting Milan and Bologna. Waste was completely removed from a part of the landfill and a trench for the train line was built. With the aim of facilitating excavation and further disposal of the material extracted, suitable measures were defined. In order to prevent undesired emissions into the excavation area, the aerobic in situ stabilisation by means of the Airflow technology took place before and during the Landfill Mining. Specific project features involved the pneumatic leachate extraction from the aeration wells (to keep the leachate table low inside the landfill and increase the volume of waste available for air migration) and the controlled moisture addition into a limited zone, for a preliminary evaluation of the effects on process enhancement. Waste and leachate were periodically sampled in the landfill during the aeration before the excavation, for quality assessment over time; the evolution of biogas composition in the landfill body and in the extraction system for different plant set-ups during the project was monitored, with specific focus on uncontrolled migration into the excavation area. Waste biological stability significantly increased during the aeration (waste respiration index dropped to 33% of the initial value after six months). Leachate head decreased from 4 to 1.5m; leachate recirculation tests proved the beneficial effects of moisture addition on temperature control, without hampering waste aerobization. Proper management of the aeration plant enabled the minimization of uncontrolled biogas emissions into the excavation area. PMID:26445364

  13. Modeling of damage due to shrinkage in autoclaved aerated concrete

    OpenAIRE

    Koudelka, T.; Kruis, J.; Sysala, S.; M. Vokáč

    2015-01-01

    The paper deals with numerical modeling of damage evolution in autoclaved aerated concrete (AAC) due to shrinkage. It represents coupled thermo-hydro-mechanical problem where the temperature and moisture transports are fully coupled. The mechanical problem is partially coupled with transport part because the AAC shrinkage is influenced by moisture evolution. These models were implemented to the SIFEL software package and they were used for numerical simulation of drying wall made from AAC blo...

  14. Sources of greenhouse gases and carbon monoxide in central London (UK)

    Science.gov (United States)

    Helfter, Carole; Tremper, Anja; Zazzeri, Giulia; Barlow, Janet F.; Nemitz, Eiko

    2015-04-01

    Biosphere-atmosphere exchange of carbon dioxide (CO2) has been on the scientific agenda for several decades and new technology now also allows for high-precision, continuous monitoring of fluxes of methane (CH4) and nitrous oxide (N2O). Compared to the natural environment, flux measurements in the urban environment, which is home to over 50% of the population globally, are still rare despite high densities of anthropogenic sources of pollutants. We report on over three years of measurements atop a 192 m tower in central London (UK), Europe's largest city, which started in October 2011. Fluxes of methane, carbon monoxide (CO) and carbon dioxide are measured by eddy-covariance (EC) at the British Telecom tower (51° 31' 17.4' N 0° 8' 20.04' W). In addition to the long-term measurements, EC fluxes of nitrous oxide (N2O) were measured in February 2014. All four trace gases exhibit diurnal trends consistent with anthropogenic activities with minimum emissions at night and early afternoon maxima. Segregating emissions by wind direction reveals heterogeneous source distributions with temporal patterns and source strengths that differ between compounds. The lowest emissions for CO, CO2 and CH4 were recorded for NW winds. The highest emissions of methane were in the SE sector, in the NE for CO2 and in the W for CO. Fluxes of all 3 gases exhibited marked seasonal trends characterised by a decrease in emissions in summer (63% reduction for CO, 36% for CO2 and 22% for CH4). Monthly fluxes of CO and CO2 were linearly correlated to air temperature (R2 = 0.7 and 0.59 respectively); a weaker dependence upon temperature was also observed for CH4 (R2 = 0.31). Diurnal and seasonal emissions of CO and CO2 are mainly controlled by local fossil fuel combustion and vehicle cold starts are thought to account for 20-30% of additional emissions of CO during the winter. Fugitive emissions of CH4 from the natural gas distribution network are thought to be substantial, which is consistent

  15. Sources and their contribution to two water-soluble organic carbon fractions at a roadway site

    Science.gov (United States)

    Park, Seung-Shik; Schauer, James J.; Cho, Sung-Yong

    2013-10-01

    24-h PM2.5 samples were collected at a roadway site every 6th day for one year (September 2010 through August 2011) and analyzed for organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), hydrophilic and hydrophobic fractions of WSOC (WSOCHPI and WSOCHPO), and ionic species, to provide important seasonal quantitative information on the primary and secondary sources of two WSOC fractions. Five minute black carbon (BC) concentrations were also measured using a seven-channel wavelength aethalometer to investigate the relationship of biomass burning (BB)-derived BC data from a BC@880 nm tracer method and WSOC. There has been increased interest in the light adsorption of WSOC and water-insoluble OC but most of the tools that have been used to understand these relationships have limited to extracts of filter-based samples. The impact of BB emissions on WSOC fractions was examined using the relationship between ΔBC (=BC@370 nm - BC@880 nm) and WSOC (or K+), and between BB tracers (WSOC and K+) and BB-derived BC (BCBB) estimated. The moderate correlation (R2 = 0.41) of WSOC and ΔBC during the cold months of November through April may support the contribution of BB emissions to the observed WSOC. Predicted BCBB correlated well with K+, WSOCHPI, and WSOCHPO concentrations (R2 of 0.65, 0.43, and 0.61, respectively), suggesting BB emissions may have an influence on the WSOC fractions observed. Contributions of non-BB, BB, and secondary OC (SOC) to both WSOCHPI and WSOCHPO were estimated using a multiple linear regression analysis. The monthly average contribution of non-BB emissions ranged from 12.6% to 29.4% of the WSOCHPI and from 21.5% to 44.1% of the WSOCHPO, with high contributions occurring during the cold months and low contributions occurred during the warm months. BB emissions contributed more to WSOCHPI (2.7%-13.1%) than WSOCHPO (0.2%-1.1%), and the SOC contribution to both WSOC fractions was significant. SOC accounted for 57.2%-79.7% of

  16. Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits.

    Science.gov (United States)

    Ozkan, Fahri; Tuna, M Cihat; Baylar, Ahmet; Ozturk, Mualla

    2014-01-01

    Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number. PMID:25225935

  17. In situ nitrogen removal from leachate by bioreactor landfill with limited aeration

    International Nuclear Information System (INIS)

    The feasibility of simultaneous nitrification and denitrification in a bioreactor landfill with limited aeration was assessed. Three column reactors, simulating bioreactor landfill operations under anaerobic condition (as reference), intermittent forced aeration and enhanced natural aeration were hence established, where aerated columns passed through two phases, i.e., fresh landfill and well-decomposed landfill. The experimental results show that limited aeration decreased nitrogen loadings of leachate distinctly in the fresh landfill. In the well-decomposed landfill, the NH4+-N of the input leachate could be nitrified completely in the aerated landfill columns. The nitrifying loadings of the column cross section reached 7.9 g N/m2 d and 16.9 g N/m2 d in the simulated landfill columns of intermittent forced aeration and enhanced natural aeration, respectively. The denitrification was influenced by oxygen distribution in the landfill column. Intermittent existence of oxygen in the landfill with the intermittent forced aeration was favorable to denitrify the NO2--N and NO3--N, indicated by the high denitrification efficiency (>99%) under the condition of BOD5/TN of more than 5.4 in leachate; locally persistent existence of oxygen in the landfill with enhanced natural aeration could limit the denitrification, indicated by relatively low denitrification efficiency of about 75% even when the BOD5/TN in leachate had an average of 7.1

  18. Source rock potential of the organic rich Turonian - Upper Campanian carbonates of northern Lebanon

    Energy Technology Data Exchange (ETDEWEB)

    Daher, S. Bou; Littke, R. [RWTH Aachen Univ. (Germany). Energy and Mineral Resources Group (EMR); Nader, F.H. [IFP Energies nouvelles, Paris (France). Dept. of Sedimentology-Stratigraphy

    2013-08-01

    Upper Cretaceous chalks, marls, and shales are arguably the most prolific petroleum source rocks in the eastern Mediterranean region. 209 core samples from the Turonian - Upper Campanian rock succession in north Lebanon were collected and analyzed for their organic matter (OM) content, quality, and maturity. The total organic carbon (TOC) measurements revealed a very good source rock potential for a 150 m interval within the Upper Santonian - Upper Campanian, with an average of 2% TOC. High HI values (average 707 mg/g TOC) characterize these source rocks as type I kerogen and reflect a very good preservation of the organic matter. T{sub max} values (average 421 C) match the other maturity parameters such as vitrinite reflectance (average 0.35%), and all point towards immature organic matter. The equivalent Upper Cretaceous in the offshore Levant basin has enough overburden to have reached maturity. However, the accurate extrapolation of the organic matter quality and quantity to the offshore is yet a challenge with the data at hand. (orig.)

  19. Growth and sporulation of Trichoderma polysporum on organic substrates by addition of carbon and nitrogen sources

    International Nuclear Information System (INIS)

    During the present study nine different organic substrates viz., rice grains, sorghum grains, wheat grains, millet grains, wheat straw, rice husk, cow dung, sawdust and poultry manure were used for mass multiplication of Trichoderma polysporum. Grains, especially sorghum grains were found to be the best substrate for T. polysporum. Wheat straw and rice husk were less suitable, whereas, cow dung, sawdust and poultry manure were not suitable for growth of the fungus. Sucrose at the rate of 30,000 ppm and ammonium nitrate at the rate of 3,000 ppm were found to be the best carbon and nitrogen sources for growth and sporulation of T. polysporum. Amendment of the selected C and N sources to wheat straw, rice husk and millet grains resulted in significantly higher growth and conidia production by T. polysporum as compared to un-amended substrates. Sorghum and rice grains showed suppression in growth and sporulation of T. polysporum when amended with C and N sources. During studies on shelf life, populations of T. polysporum attained the peck at 60-135 days intervals on different substrates and declined gradually thereafter. However, even after 330 days, the populations were greater than the population at 0-day. At 345-360 days interval, populations were less than the initial populations at 0- days. Shelf life on C+N amended wheat straw and rice husk were more as compared to un-amended substrates. (author)

  20. Rapid biological oxidation of methanol in the tropical Atlantic: significance as a microbial carbon source

    Directory of Open Access Journals (Sweden)

    J. L. Dixon

    2011-04-01

    Full Text Available Methanol is the second most abundant organic gas in the atmosphere after methane, and is ubiquitous in the troposphere. It plays a significant role in atmospheric oxidant chemistry and is biogeochemically active. Large uncertainties exist about whether the oceans are a source or sink of methanol to the atmosphere. Even less is understood about what reactions in seawater determine its concentration, and hence flux across the sea surface interface. We report here concentrations of methanol up to 300 nM, with corresponding microbial uptake rates between 2–146 nM d−1, suggesting turnover times as low as 1 day in surface waters of the oligotrophic tropical North East Atlantic. Comparisons with parallel determinations of bacterial leucine uptake suggest that methanol contributes on average 13% to bacterial carbon demand in the central northern Atlantic gyre (maximum of 54%. However, our low air to sea methanol flux estimates of 7.2–13 μmol m−2 d−1 suggest that the atmosphere is not a major source. We conclude that there must be a major, as yet unidentified, in situ oceanic methanol source in these latitudes which we suggest is sunlight driven decomposition of organic matter.

  1. Production of Poly(3-Hydroxybutyrate-co-3-Hydroxyhexanoate) Using Aeromonas hydrophila 4AK4 Grown in Mixed Carbon Source

    Institute of Scientific and Technical Information of China (English)

    张瑾; 张广; 陈金春; 华秀英; 陈国强

    2002-01-01

    Aeromonas hydrophila 4AK4 was grown on mixed substrates of soybean oil and lauric acid for the production of polyhydroxyalkanoate copolymer consisting of 3-hydroxybutyrate (3HB) and 3-hydroxyhexanoate (3HHx). A maximal poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) content of 49.13% in dry cells was obtained in a shake flask culture. PHBHHx of 6.26 -g/L was produced in a fermentation experiment over 48 -h on a sole carbon source containing 100 -g/L soybean oil, while 12.40 -g/L PHBHHx was produced on a mixed carbon source containing 80 -g/L soybean and 20 g/L lauric acid over the same period of time, resulting in a polyhydroxyalkanoate (PHA) productivity of 0.25 -g/(L*h). The results show that mixed carbon sources are suitable for industrialized production of PHBHHx from A. hydrophila 4AK4, as the mixed carbon sources also overcome the foaming problem that occurs when lauric acid is employed as a sole carbon source in PHBHHx production.

  2. Effect of various carbon and nitrogen sources on decolorization of textile dye remazol golden yellow using bacterial species.

    Science.gov (United States)

    Palanivelan, R; Rajakumar, S; Ayyasamy, P M

    2014-09-01

    Textile dyes with different chemical structures are consistently used in textile industries and they are being recalcitrant xenobiotic in nature. The aim of present research is directed to finding the preference of striking carbon and nitrogen sources on remazol golden yellow decolorization. Bacterial strains were isolated, screened and tested for dye degradation of remazol golden yellow in basal medium amended with different carbon and nitrogen sources. This study was carried out for the period of 12 d at 37 degrees C. Among various carbon and nitrogen sources, starch and yeast extracts promote maximum decolorization in the medium inoculated with Bacillus. sp. (ESL-52). Nevertheless, the rate of decolorization was less in the medium amended with various carbon and nitrogen sources in the presence of Bacillus sp. (TSL-9), Micrococcus sp. (TSL-7), Pseudomonas sp. (M-1) and Staphylococcus sp. (ES-37) respectively. The results clearly showed that addition of significant organic carbon and nitrogen sources are only desirable co-substrates for bacterial dye decolorization process. PMID:25204047

  3. Life cycle inventory analysis of bio-based polyester production by genetically engineered bacteria from renewable carbon sources

    Energy Technology Data Exchange (ETDEWEB)

    Tsuge, T.; Akiyama, M.; Doi, Y. [Tokyo Inst. of Technology, SORST Group of Japan Science and Technology Corp., Tokyo (Japan). Dept. of Innovative and Engineered Materials]|[RIKEN Inst., Saitama (Japan). Polymer Chemistry Lab

    2003-07-01

    Since the oil crisis in the 1970s, polydroxyalkanoates (PHAs) have been considered to be an environmentally sound substitute for oil because they are biodegradable, leave no waste and are made from renewable resources such as glucose, sucrose and vegetable oils. This study was conducted to predict the production cost of a polydroxyalkanoates (PHA) copolyester using soybean oil as a carbon source. PHAs are used as biodegradable thermoplastics. They are bio-based polymers which can be made from various microorganisms. This simulation study used a recombinant strain of Ralstonia eutropha harboring a PHA synthase gene from Aeromonas caviae. Life cycle inventories of energy consumption and carbon dioxide emissions were calculated and compared with other microbial production of poly3-hydroxybutyrate from glucose as a carbon source. It was determined that life cycle inventories of energy consumption and carbon dioxide emissions of bio-based polymers are significantly lower than those of typical petrochemical polymers. 10 refs., 3 tabs., 4 figs.

  4. Sources of Organic-Carbon in the Littoral of Lake Gloomier as Indicated by Stable Carbon-Isotope and Carbohydrate Compositions

    NARCIS (Netherlands)

    Boschker, H.T.S.; Dekkers, E.M.J.; Pel, R.; Cappenberg, T.E.

    1995-01-01

    The relative importance of potential carbon sources in the littoral of Lake Gooimeer, a lake in the centre of the Netherlands, was studied using a combination of C-13/C-12-ratio analysis and carbohydrate composition analysis. The littoral is covered on the land side by a 80 m wide Phragmites austral

  5. Continental Scale Antarctic deposition of sulphur and black carbon from anthropogenic and volcanic sources

    Directory of Open Access Journals (Sweden)

    H.-F. Graf

    2009-12-01

    Full Text Available While Antarctica is often described as a pristine environment, the potential threats from local pollution sources including tourist ships and emissions associated with scientific activities have recently been raised. However, to date there has been no systematic attempt to model the impacts of such pollutants at the continental scale. Indeed, until very recently there was not even a sulphur emission budget available for Antarctica. Here we present the first comprehensive study of atmospheric pollution in Antarctica using a limited area chemistry climate model, and a monthly emissions inventory for sulphur from maintenance of research stations, ground and air traffic, shipping and the active volcano Mt. Erebus. We find that ship emissions, both sulphurous and black carbon, dominate anthropogenic pollution near the ground. These are likely to rise considerably if recent trends in tourism continue.

  6. Enhanced biological phosphorus removal. Carbon sources, nitrate as electron acceptor, and characterization of the sludge community

    Energy Technology Data Exchange (ETDEWEB)

    Christensson, M.

    1997-10-01

    Enhanced biological phosphorus removal (EBPR) was studied in laboratory scale experiments as well as in a full scale EBPR process. The studies were focused on carbon source transformations, the use of nitrate as an electron acceptor and characterisation of the microflora. A continuous anaerobic/aerobic laboratory system was operated on synthetic wastewater with acetate as sole carbon source. An efficient EBPR was obtained and mass balances over the anaerobic reactor showed a production of 1.45 g poly-{beta}-hydroxyalcanoic acids (PHA), measured as chemical oxygen demand (COD), per g of acetic acid (as COD) taken up. Furthermore, phosphate was released in the anaerobic reactor in a ratio of 0.33 g phosphorus (P) per g PHA (COD) formed and 0.64 g of glycogen (COD) was consumed per g of acetic acid (COD) taken up. Microscopic investigations revealed a high amount of polyphosphate accumulating organisms (PAO) in the sludge. Isolation and characterisation of bacteria indicated Acinetobacter spp. to be abundant in the sludge, while sequencing of clones obtained in a 16S rDNA clone library showed a large part of the bacteria to be related to the high mole % G+C Gram-positive bacteria and only a minor fraction to be related to the gamma-subclass of proteobacteria to which Acinetobacter belongs. Operation of a similar anaerobic/aerobic laboratory system with ethanol as sole carbon source showed that a high EBPR can be achieved with this compound as carbon source. However, a prolonged detention time in the anaerobic reactor was required. PHA were produced in the anaerobic reactor in an amount of 1.24 g COD per g of soluble DOC taken up, phosphate was released in an amount of 0.4-0.6 g P per g PHA (COD) produced and 0.46 g glycogen (COD) was consumed per g of soluble COD taken up. Studies of the EBPR in the UCT process at the sewage treatment plant in Helsingborg, Sweden, showed the amount of volatile fatty acids (VFA) available to the PAO in the anaerobic stage to be

  7. Evaluation of biobutanol production by Clostridium beijerinckii NRRL B-592 using sweet sorghum as carbon source

    Directory of Open Access Journals (Sweden)

    Luiz Jardel Visioli

    2015-09-01

    Full Text Available In this research it was evaluated the production of biobutanol by Clostridium beijerinckiiNRRL B-592 using sweet sorghum juice as carbon source. Operational variables, like pH and initial inoculum size, as well as supplementation of industrial media with yeast extract and tryptone, were evaluated. The maximum butanol obtained was 2.12g kg-1 using 12.5% of inoculum size, 0.05g 100mL-1 of tryptone and 0.1g 100mL-1 of yeast extract and initial pH of 5.5. The main contribution of this research was to show a systematic procedure for development of a low cost industrial media for biobutanol production from sweet sorghum.

  8. Regulatory switches for hierarchical use of carbon sources in E. coli

    Directory of Open Access Journals (Sweden)

    Ruth S. Perez-Alfaro

    2014-09-01

    Full Text Available In this work we study the preferential use of carbon sources in the bacterium Escherichia coli. To that end we engineered transcriptional fusions of the reporter gene gfpmut2, downstream of transcription-factor promoters, and analyzed their activity under several conditions. The chosen transcription factors are known to regulate catabolic operons associated to the consumption of alternative sugars. The obtained results indicate the following hierarchical order of sugar preference in this bacterium: glucose > arabinose > sorbitol > galactose. Further dynamical results allowed us to conjecture that this hierarchical behavior might be operated by at least the following three regulatory strategies: 1 the coordinated activation of the corresponding operons by the global regulator catabolic repressor protein (CRP, 2 their asymmetrical responses to specific and unspecific sugars and, 3 the architecture of the associated gene regulatory networks.

  9. Hetero-junction carbon nanotube FET with lightly doped drain and source regions

    Science.gov (United States)

    Yousefi, Reza; Doorzad, Leila

    2016-01-01

    In this paper, a new structure was introduced for carbon nanotube (CNT) MOSFET transistors. The proposed structure was composed of two different nanotubes for the source/drain and channel regions. Electrical characteristics of this structure were investigated using nonequilibrium Green’s function approach. Results of the simulations demonstrated that the proposed hetero-structure had almost the same ON-current and much less OFF-current and as a result higher ION/IOFF ratio than the conventional homo-structure. Results of the comparison between switching behavior in equal ION/IOFF ratio showed that, although the proposed structure had longer delay, its power dissipation for every switching event was less than that of the conventional structure. A further comparison of the switching characteristic in equal ON-current values showed that the proposed structure enjoys from shorter delay and also consumes less power-delay product (PDP) when compared to the LDDS structure.

  10. Direct growth of graphene on gallium nitride using C2H2 as carbon source

    Science.gov (United States)

    Wang, Bing; Zhao, Yun; Yi, Xiao-Yan; Wang, Guo-Hong; Liu, Zhi-Qiang; Duan, Rui-Rei; Huang, Peng; Wang, Jun-Xi; Li, Jin-Min

    2016-04-01

    Growing graphene on gallium nitride (GaN) at temperatures greater than 900°C is a challenge that must be overcome to obtain high quality of GaN epi-layers. We successfully met this challenge using C2H2 as the carbon source. We demonstrated that graphene can be grown both on copper and directly on GaN epi-layers. The Raman spectra indicated that the graphene films were about 4-5 layers thick. Meanwhile, the effects of the growth temperature on the growth of the graphene films were systematically studied, and 830°C was found to be the optimum growth temperature. We successfully grew high-quality graphene films directly on gallium nitride.

  11. Synthesis of WC-Co nanocomposites using polymer as carbon source

    International Nuclear Information System (INIS)

    Ceramic-metal composites such as WC-Co are attractive for cutting-tool applications as they have high hardness, chemical inertness and resistance to heat. The properties and performance of these composites can be enhanced by keeping the size of the components on a manometer scale. Synthesis of WC-Co nanocomposites generally involves gas-phase carburization. The authors have developed a novel approach in which a polymer precursor such as polyacrylonitrile serves as an in situ source for carbon. The WC-Co nanocomposites formed are characterized by x-ray diffraction and electron microscopy. The synthesis and processing conditions such as firing temperature, time and atmosphere play a critical role in obtaining phase-pure products

  12. Thermoascus aurantiacus CBHI/Cel7A Production in Trichoderma reesei on Alternative Carbon Sources

    Science.gov (United States)

    Benkő, Zsuzsa; Drahos, Eszter; Szengyel, Zsolt; Puranen, Terhi; Vehmaanperä, Jari; Réczey, Kati

    To develop functional enzymes in cellulose hydrolysis at or above 70°C the cellobiohydrolase (CBHI/Cel7A) of Thermoascus aurantiacus was cloned and expressed in Trichoderma reesei Rut-C30 under the strong cbh1 promoter. Cellulase production of the parental strain and the novel strain (RF6026) was examined in submerged fermentation experiments using various carbon sources, which were lactose, Solka Floc 200 cellulose powder, and steam pretreated corn stover. An industrially feasible production medium was used containing only distiller's spent grain, KH2PO4, and (NH4)2SO4. Enzyme production was followed by measurements of protein concentration, total cellulase enzyme activity (filter paper activity), β-glucosidase activity, CBHI activity, and endogenase I (EGI) activity. The Thermoascus CBHI/Cel7A activity was taken as an indication of the heterologous gene expression under the cbh1 promoter.

  13. Brown carbon aerosol in the North American continental troposphere: sources, abundance, and radiative forcing

    Science.gov (United States)

    Liu, J.; Scheuer, E.; Dibb, J.; Diskin, G. S.; Ziemba, L. D.; Thornhill, K. L.; Anderson, B. E.; Wisthaler, A.; Mikoviny, T.; Devi, J. J.; Bergin, M.; Perring, A. E.; Markovic, M. Z.; Schwarz, J. P.; Campuzano-Jost, P.; Day, D. A.; Jimenez, J. L.; Weber, R. J.

    2015-07-01

    Chemical components of organic aerosol (OA) selectively absorb light at short wavelengths. In this study, the prevalence, sources, and optical importance of this so-called brown carbon (BrC) aerosol component are investigated throughout the North American continental tropospheric column during a summer of extensive biomass burning. Spectrophotometric absorption measurements on extracts of bulk aerosol samples collected from an aircraft over the central USA were analyzed to directly quantify BrC abundance. BrC was found to be prevalent throughout the 1 to 12 km altitude measurement range, with dramatic enhancements in biomass-burning plumes. BrC to black carbon (BC) ratios, under background tropospheric conditions, increased with altitude, consistent with a corresponding increase in the absorption Ångström exponent (AAE) determined from a three-wavelength particle soot absorption photometer (PSAP). The sum of inferred BC absorption and measured BrC absorption at 365 nm was within 3 % of the measured PSAP absorption for background conditions and 22 % for biomass burning. A radiative transfer model showed that BrC absorption reduced top-of-atmosphere (TOA) aerosol forcing by ~ 20 % in the background troposphere. Extensive radiative model simulations applying this study background tropospheric conditions provided a look-up chart for determining radiative forcing efficiencies of BrC as a function of a surface-measured BrC : BC ratio and single scattering albedo (SSA). The chart is a first attempt to provide a tool for better assessment of brown carbon's forcing effect when one is limited to only surface data. These results indicate that BrC is an important contributor to direct aerosol radiative forcing.

  14. Carbon sources in the Beaufort Sea revealed by molecular lipid biomarkers and compound specific isotope analysis

    Directory of Open Access Journals (Sweden)

    I. Tolosa

    2012-10-01

    Full Text Available Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids and compound specific isotope analysis of suspended particulate organic matter (SPM and surface sediments of the Mackenzie Shelf and slope (Southeast Beaufort Sea, Arctic Ocean, were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the sedimentary organic matter (OM.

    Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and < 1%, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (> 80% with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75% whereas those from the slope contained the highest proportion of fossil (40% and C3 terrestrial plant material (10%. Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the

  15. Effect of unconventional carbon sources on biosurfactant production and its application in bioremediation.

    Science.gov (United States)

    Jain, Rakeshkumar M; Mody, Kalpana; Joshi, Nidhi; Mishra, Avinash; Jha, Bhavanath

    2013-11-01

    The potential of an alkaliphilic bacterium Klebsiella sp. strain RJ-03, to utilize different unconventional carbon sources for the production of biosurfactant was evaluated. The biosurfactant produced using corn powder, potato peel powder, Madhuca indica and sugarcane bagasse containing medium, exhibited significantly higher viscosity and maximum reduction in surface tension as compared to other substrates. Among several carbon substrates tested, production of biosurfactant was found to be the highest with corn powder (15.40 ± 0.21 g/l) as compared to others. The comparative chemical characterization of purified biosurfactant was done using advance analytical tools such as NMR, FT-IR, SEM, GPC, MALDI TOF-TOF MS, GC-MS, TG and DSC. Analyses indicated variation in the functional groups, monosaccharide composition, molecular mass, thermostability. Higher yield with cheaper raw materials, noteworthy stress tolerance of CP-biosurfactant toward pH and salt as well as compatibility with chemical surfactants and detergents revealed its potential for commercialization and application in bioremediation. PMID:23994788

  16. Graphene film formation on insulating substrates using polymer films as carbon source

    International Nuclear Information System (INIS)

    Graphene films were formed on sapphire surfaces using polymethylmethacrylate (PMMA) polymer films as a carbon source and characterized by Raman spectroscopy. For large-scale, uniform growth, a spin-on-glass (SOG)/Cu-catalyst/PMMA/sapphire layered structure was annealed in Ar–H2 flow at atmospheric pressure. We found that the SOG cover layer is effective to suppress evaporation and agglomeration of the Cu film. We also confirmed that morphology and quality of grown graphene films are dramatically improved by hydrogen etching of buried bulky carbon produced by the polymer pyrolysis at the Cu/sapphire interfaces. Quality of graphene films grown at the catalyst-layer/sapphire interface was compared with that on the catalyst surface using Ni/PMMA, PMMA/Ni and Ni/PMMA/Ni layered structures. Quality of graphene films grown at the Ni/sapphire interfaces was found to be lower than that on the Ni surfaces, suggesting that strain engineering at the buried Ni/graphene/sapphire interfaces and/or etching technique to remove the wastes of polymer pyrolysis should be improved. (paper)

  17. Analysis of factors affecting the accuracy, reproducibility, and interpretation of microbial community carbon source utilization patterns

    Science.gov (United States)

    Haack, S.K.; Garchow, H.; Klug, M.J.; Forney, L.J.

    1995-01-01

    We determined factors that affect responses of bacterial isolates and model bacterial communities to the 95 carbon substrates in Biolog microliter plates. For isolates and communities of three to six bacterial strains, substrate oxidation rates were typically nonlinear and were delayed by dilution of the inoculum. When inoculum density was controlled, patterns of positive and negative responses exhibited by microbial communities to each of the carbon sources were reproducible. Rates and extents of substrate oxidation by the communities were also reproducible but were not simply the sum of those exhibited by community members when tested separately. Replicates of the same model community clustered when analyzed by principal- components analysis (PCA), and model communities with different compositions were clearly separated un the first PCA axis, which accounted for >60% of the dataset variation. PCA discrimination among different model communities depended on the extent to which specific substrates were oxidized. However, the substrates interpreted by PCA to be most significant in distinguishing the communities changed with reading time, reflecting the nonlinearity of substrate oxidation rates. Although whole-community substrate utilization profiles were reproducible signatures for a given community, the extent of oxidation of specific substrates and the numbers or activities of microorganisms using those substrates in a given community were not correlated. Replicate soil samples varied significantly in the rate and extent of oxidation of seven tested substrates, suggesting microscale heterogeneity in composition of the soil microbial community.

  18. Carbon monoxide poisoning in Beirut, Lebanon: Patient′s characteristics and exposure sources

    Directory of Open Access Journals (Sweden)

    Mazen J El Sayed

    2014-01-01

    Full Text Available Background: Carbon monoxide (CO poisoning is a preventable disease. Patients present with nonspecific symptoms post CO exposure. Causal factors are well described in developed countries, but less in developing countries. Objectives: This study examined the characteristics of patients with CO poisoning treated at a tertiary care center in Beirut, Lebanon, and their association with the CO poisoning source. Materials and Methods: A retrospective chart review of all patients who presented to the Emergency Department (ED of the American University of Beirut Medical Center (AUBMC over 4-year period and for whom a carboxyhemoglobin (CO-Hb level was available. Patients with CO poisoning diagnosis were included in the study. Patients′ characteristics and their association with CO poisoning source were described. Results: Twenty-seven patients were treated for CO poisoning during the study period, 55% of whom were males. Headache was the most common presenting symptom (51.9%. Burning charcoal indoors was the most common causal factor (44.4%, whereas fire-related smoke was another causal factor. The median arterial CO-Hb level on presentation for all cases was 12.0% (interquartile range (IQR 7.3-20.2. All patients received normobaric oxygen therapy. No complications were documented in the ED. All patients were discharged from the ED with a median ED length of stay of 255 min (IQR 210-270. Young females were more likely to present with CO poisoning from burning charcoal indoors than from another cause. Conclusion: CO poisoning in Beirut, Lebanon is mainly due to charcoal burning grills used indoors and to fire-related smoke. A clinically significant association was present between gender and CO poisoning source. An opportunity for prevention is present in terms of education and increased awareness regarding CO emission sources.

  19. Efficient and cost-reduced glucoamylase fed-batch production with alternative carbon sources.

    Science.gov (United States)

    Luo, Hongzhen; Liu, Han; He, Zhenni; Zhou, Cong; Shi, Zhongping

    2015-02-01

    Glucoamylase is an important industrial enzyme. Glucoamylase production by industrial Aspergillus niger strain featured with two major problems: (i) empirical substrate feeding methods deteriorating the fermentation performance; and (ii) the high raw materials cost limiting the economics of the glucoamylase product with delegated specification. In this study, we first proposed a novel three-stage varied-rate substrate feeding strategy for efficient glucoamylase production in a 5 L bioreactor using the standard feeding medium, by comparing the changing patterns of the important physiological parameters such as DO, OUR, RQ, etc., when using different substrate feeding strategies. With this strategy, the glucoamylase activity and productivity reached higher levels of 11,000 U/ml and 84.6 U/ml/h, respectively. The performance enhancement in this case was beneficial from the following results: DO and OUR could be controlled at the higher levels (30%, 43.83 mmol/l/h), while RQ was maintained at a stable/lower level of 0.60 simultaneously throughout the fed-batch phase. Based on this three-stage varied-rate substrate feeding strategy, we further evaluated the economics of using alternative carbon sources, attempting to reduce the raw materials cost. The results revealed that cornstarch hydrolysate could be considered as the best carbon source to replace the standard and expensive feeding medium. In this case, the production cost of the glucoamylase with delegated specification (5,000 U/ml) could be saved by more than 61% while the product quality be ensured simultaneously. The proposed strategy showed application potential in improving the economics of industrial glucoamylase production. PMID:25262682

  20. Antifungal activity of clotrimazole against Candida albicans depends on carbon sources, growth phase and morphology.

    Science.gov (United States)

    Kasper, Lydia; Miramón, Pedro; Jablonowski, Nadja; Wisgott, Stephanie; Wilson, Duncan; Brunke, Sascha; Hube, Bernhard

    2015-07-01

    Vulvovaginal candidiasis, a superficial infection caused predominantly by the pathogenic fungus Candida albicans, is frequently treated with clotrimazole. Some drug formulations contain lactate for improved solubility. Lactate may modify C. albicans physiology and drug sensitivity by serving as a carbon source for the fungus and/or affecting local pH. Here, we explored the effects of lactate, in combination with pH changes, on C. albicans proliferation, morphology and clotrimazole sensitivity. Moreover, we determined the influence of growth phase and morphology per se on drug sensitivity. We showed that utilization of lactate as a carbon source did not promote fast fungal proliferation or filamentation. Lactate had no influence on clotrimazole-mediated killing of C. albicans in standard fungal cultivation medium but had an additive effect on the fungicidal clotrimazole action under in vitro vagina-simulative conditions. Moreover, clotrimazole-mediated killing was growth-phase and morphology dependent. Post-exponential cells were resistant to the fungicidal action of clotrimazole, whilst logarithmic cells were sensitive, and hyphae showed the highest susceptibility. Finally, we showed that treatment of pre-formed C. albicans hyphae with sublethal concentrations of clotrimazole induced a reversion to yeast-phase growth. As C. albicans hyphae are considered the pathogenic morphology during mucosal infections, these data suggest that elevated fungicidal activity of clotrimazole against hyphae plus clotrimazole-induced hyphae-to-yeast reversion may help to dampen acute vaginal infections by reducing the relative proportion of hyphae and thus shifting to a non-invasive commensal-like population. In addition, lactate as an ingredient of clotrimazole formulations may potentiate clotrimazole killing of C. albicans in the vaginal microenvironment. PMID:25976001