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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.

  2. 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...

  3. Influence of aeration and carbon source on production of microcin B17 by Escherichia coli ZK650.

    Science.gov (United States)

    Fang, A; Demain, A L

    1997-05-01

    Previous studies [Connell et al. (1987) Mol Microbiol 1: 195-201] have shown that expression of the microcin B17 (MccB17) promoter is inversely related to the growth rate of the culture, when slower growth was brought about by limitation of sources of carbon, nitrogen or phosphorus. When we used oxygen limitation to decrease growth in a glucose-based chemically defined medium, we found specific MccB17 production to be positively related to growth rate and extent. On the other hand, when we examined various nutritional variations of media, specific production of MccB17 showed a negative relationship to growth rate and extent, as would be predicted by the findings of Connell et al. (1987). Glucose, glycerol and acetate were found to repress MccB17 production; succinate was not repressive. Succinate is an excellent carbon source for production of MccB17 since high levels can be used with no or little interference in product synthesis.

  4. 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...

  5. 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...

  6. 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.

  7. 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.

  8. 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...

  9. 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...

  10. Influence of temperature on carbon and nitrogen dynamics during in situ aeration of aged waste in simulated landfill bioreactors.

    Science.gov (United States)

    Tong, Huanhuan; Yin, Ke; Giannis, Apostolos; Ge, Liya; Wang, Jing-Yuan

    2015-09-01

    The effect of temperature on carbon and nitrogen compounds during in situ aeration of aged waste was investigated in lab-scale simulated landfill bioreactors at 35, 45 and 55 °C, respectively. The bioreactor operated at 55 °C presented the highest carbon mineralization rate in the initial stage, suggesting accelerated biodegradation rates under thermophilic conditions. The nitrogen speciation study indicated that organic nitrogen was the dominant species of total N in aerobic bioreactors due to ammonia removal. Leachate organic nitrogen was further fractionated to elucidate the fate of individual constituent. Detailed investigation revealed the higher bioconversion rates of N-humic and N-fulvic compounds compared to hydrophilic compounds in thermophilic conditions. At the end, waste material in 55 °C bioreactor was richer in highly matured humic substances (HS) verifying the high bioconversion rates.

  11. Combination of ozonation, activated carbon, and biological aerated filter for advanced treatment of dyeing wastewater for reuse.

    Science.gov (United States)

    Zou, Xiao-Ling

    2015-06-01

    Laboratorial scale experiments were performed to investigate and evaluate the performance and removal characteristics of organics, color, and genotoxicity by an integrated process including ozonation, activated carbon (AC), and biological aerated filter (BAF) for recycling biotreated dyeing wastewater (BTDW) collected from a cotton textile factory. Influent chemical oxygen demand (COD) in the range of 156 - 252 mg/L, 5-day biochemical oxygen demand (BOD5) of 13.5 - 21.7 mg/L, and color of 58 - 76° were observed during the 20-day continuous operation. Outflows with average COD of 43 mg/L, BOD5 of 6.6 mg/L, and color of 5.6° were obtained after being decontaminated by the hybrid system with ozone dosage of 0.25 mg O3applied/mg COD0, 40 min ozonation contact time, 30 min hydraulic retention time (HRT) for AC treatment, and 2.5 h HRT for BAF treatment. More than 82 % of the genotoxicity of BTDW was eliminated in the ozonation unit. The genotoxicity of the BAF effluent was less than 1.33 μg 4-nitroquinoline-N-oxide/L. Ozonation could change the organics molecular structures, destroy chromophores, increase the biodegradability, and obviously reduce the genotoxicity of BTDW. Results showed that the combined process could guarantee water reuse with high quality.

  12. 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.

  13. 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...

  14. 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.

  15. 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%.

  16. 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...

  17. 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.

  18. 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.

  19. 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 ...

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  5. Effects of chemical oxygen demand (COD)/N ratios on pollutants removal in the subsurface wastewater infiltration systems with/without intermittent aeration.

    Science.gov (United States)

    Song, Siyu; Pan, Jing; Wu, Shiwei; Guo, Yijing; Yu, Jingxiao; Shan, Qingchi

    2016-01-01

    The matrix oxidation reduction potential level, organic pollutants and nitrogen removal performances of eight subsurface wastewater infiltration systems (SWISs) (four with intermittent aeration, four without intermittent aeration) fed with influent chemical oxygen demand (COD)/N ratio of 3, 6, 12 and 18 were investigated. Nitrification of non-aerated SWISs was poor due to oxygen deficiency while higher COD/N ratios further led to lower COD and nitrogen removal rate. Intermittent aeration achieved almost complete nitrification, which successfully created aerobic conditions in the depth of 50 cm and did not change anoxic or anaerobic conditions in the depth of 80 and 110 cm. The sufficient carbon source in high COD/N ratio influent greatly promoted denitrification in SWISs with intermittent aeration. High average removal rates of COD (95.68%), ammonia nitrogen (NH4(+)-N) (99.32%) and total nitrogen (TN) (89.65%) were obtained with influent COD/N ratio of 12 in aerated SWISs. The results suggest that intermittent aeration was a reliable option to achieve high nitrogen removal in SWISs, especially with high COD/N ratio wastewater.

  6. 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.

  7. 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.)

  8. 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...

  9. 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.

  10. 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

  11. Enhanced organics and nitrogen removal in batch-operated vertical flow constructed wetlands by combination of intermittent aeration and step feeding strategy.

    Science.gov (United States)

    Fan, Jinlin; Liang, Shuang; Zhang, Bo; Zhang, Jian

    2013-04-01

    Oxygen and carbon source supply are usually insufficient in subsurface flow constructed wetlands. Simultaneous removal of organic pollutants and nitrogen in five batch-operated vertical flow constructed wetlands under different operating conditions was investigated. Alternate aerobic and anaerobic regions were created well with intermittent aeration. Four-month experiments showed that the wetland-applied intermittent aeration combined with step feeding strategy (reactor E) greatly improved the removal of organics, ammonium nitrogen (NH4-N), and total nitrogen (TN) simultaneously, which were 97, 96, and 82%, respectively. It was much better than non-aerated reactors A and B and outperformed intermittently aerated reactor D without step feeding. Continuous aeration (reactor C) significantly enhanced the organics removal and nitrification, but it limited the TN removal (29%) seriously as a result of low denitrification level, and the high operation cost remained a question. The effect of plants was confirmed in this study, and the monitoring data showed that the plants could grow normally. Intermittent aeration as well as step feeding had no obvious influence on the growth of wetland plants in this study.

  12. 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.

  13. 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.

  14. 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.

  15. [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

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Partial nitritation ANAMMOX in submerged attached growth bioreactors with smart aeration at 20 °C.

    Science.gov (United States)

    Shannon, James M; Hauser, Lee W; Liu, Xikun; Parkin, Gene F; Mattes, Timothy E; Just, Craig L

    2015-01-01

    Submerged attached growth bioreactors (SAGBs) were operated at 20 °C for 30 weeks in smart-aerated, partial nitritation ANAMMOX mode and in a timer-controlled, cyclic aeration mode. The smart-aerated SAGBs removed 48-53% of total nitrogen (TN) compared to 45% for SAGBs with timed aeration. Low dissolved oxygen concentrations and cyclic pH patterns in the smart-aerated SAGBs suggested conditions favorable to partial nitritation ANAMMOX and stoichiometrically-derived and numerically modeled estimations attributed 63-68% and 14-44% of TN removal to partial nitritation ANAMMOX in these bioreactors, respectively. Ammonia removals of 36-67% in the smart-aerated SAGBs, with measured oxygen and organic carbon limitations, further suggest partial nitritation ANAMMOX. The smart-aerated SAGBs required substantially less aeration to achieve TN removals similar to SAGBs with timer-controlled aeration. Genomic DNA testing confirmed that the dominant ANAMMOX seed bacteria, received from a treatment plant utilizing the DEMON® sidestream deammonification process, was a Candidatus Brocadia sp. (of the Planctomycetales order). The DNA from these bacteria was also present in the SAGBs at the conclusion of the study providing evidence for attached growth and limited biomass washout.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Anammox brings WWTP closer to energy autarky due to increased biogas production and reduced aeration energy for N-removal.

    Science.gov (United States)

    Siegrist, H; Salzgeber, D; Eugster, J; Joss, A

    2008-01-01

    Fifty years ago when only BOD was removed at municipal WWTPs primary clarifiers were designed with 2-3 hours hydraulic retention time (HRT). This changed with the introduction of nitrogen removal in activated sludge treatment that needed more BOD for denitrification. The HRT of primary clarification was reduced to less than one hour for dry weather flow with the consequence that secondary sludge had to be separately thickened and biogas production was reduced. Only recently the ammonia rich digester liquid (15-20% of the inlet ammonia load) could be treated with the very economic autotrophic nitritation/anammox process requiring half of the aeration energy and no organic carbon source compared to nitrification and heterotrophic denitrification. With the introduction of this new innovative digester liquid treatment the situation reverts, allowing us to increase HRT of the primary clarifier to improve biogas production and reduce aeration energy for BOD removal and nitrification at similar overall N-removal. PMID:18309216

  11. ENVIRONMENTAL BIODEGRADABILITY OF [14C] SINGLE-WALLED CARBON NANOTUBESBY TRAMETES VERSICOLOR AND NATURAL MICROBIAL CULTURES FOUND IN NEWBEDFORD HARBOR SEDIMENT AND AERATED WASTEWATER TREATMENT PLANT SLUDGE

    Science.gov (United States)

    Little is known about environmental biodegradability or biotransformations of single-walled carbon nanotubes (SWNT). Because of their strong association with aquatic organic matter, detailed knowledge of the ultimate fate and persistence of SWNT requires investigation of possible...

  12. The effect of aeration position on the spatial distribution and reduction of pollutants in the landfill stabilization process--a pilot scale study.

    Science.gov (United States)

    Chai, Xiaoli; Hao, Yongxia; Shimaoka, Takayuki; Nakayama, Hirofumi; Komiya, Teppei; Zhao, Youcai

    2013-01-01

    Three pilot-scale simulators with different aeration systems were constructed to explore the effects of aeration position on the reduction of pollutants. The simulator with a bottom aeration system successfully distributed oxygen and efficiently inhibited methane production. A close relationship was found between the oxygen distribution and the removal of pollutants, especially that of nitrogen. The transition between nitrification and denitrification in the longitude direction of the simulator with a bottom aeration system contributed to nitrogen removal in aerobic conditions. This process can be defined as a new path for nitrogen removal in addition to simultaneous nitrification and denitrification. The concentration of NH4+ -N total nitrogen and total organic carbon dropped to 3, 78 and 204 mg L(-1), respectively, after 312 days of bottom aeration and to 514, 659 and 828 mg L(-1), respectively, after 312 days of top aeration. These results indicate that the bottom aeration system was more efficient for reducing pollutants than the top aeration system.

  13. Numerical simulation of landfill aeration using computational fluid dynamics.

    Science.gov (United States)

    Fytanidis, Dimitrios K; Voudrias, Evangelos A

    2014-04-01

    The present study is an application of Computational Fluid Dynamics (CFD) to the numerical simulation of landfill aeration systems. Specifically, the CFD algorithms provided by the commercial solver ANSYS Fluent 14.0, combined with an in-house source code developed to modify the main solver, were used. The unsaturated multiphase flow of air and liquid phases and the biochemical processes for aerobic biodegradation of the organic fraction of municipal solid waste were simulated taking into consideration their temporal and spatial evolution, as well as complex effects, such as oxygen mass transfer across phases, unsaturated flow effects (capillary suction and unsaturated hydraulic conductivity), temperature variations due to biochemical processes and environmental correction factors for the applied kinetics (Monod and 1st order kinetics). The developed model results were compared with literature experimental data. Also, pilot scale simulations and sensitivity analysis were implemented. Moreover, simulation results of a hypothetical single aeration well were shown, while its zone of influence was estimated using both the pressure and oxygen distribution. Finally, a case study was simulated for a hypothetical landfill aeration system. Both a static (steadily positive or negative relative pressure with time) and a hybrid (following a square wave pattern of positive and negative values of relative pressure with time) scenarios for the aeration wells were examined. The results showed that the present model is capable of simulating landfill aeration and the obtained results were in good agreement with corresponding previous experimental and numerical investigations.

  14. 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.

  15. 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).

  16. 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…

  17. The source of carbon dioxide for gastric acid production.

    Science.gov (United States)

    Steer, Howard

    2009-01-01

    The source of carbon dioxide for the chemical reaction leading to the production of gastric acid is unknown. The decarboxylation of an amino acid releases carbon dioxide. Pepsinogens provide a rich source of the amino acid arginine. Both the source of carbon dioxide, arginine, and the consequence of arginine decarboxylation, agmatine, have been studied. The site of carbon dioxide production has been related to the survival of the parietal cell. An immunohistochemical study has been carried out on glycol methacrylate embedded gastric biopsies from the normal stomach of 38 adult patients. The sections have been stained using polyclonal antibody to pepsinogen II, polyclonal antibody to agmatine, and polyclonal antibody to Helicobacter pylori. Pepsinogen II and agmatine are found in the parietal cell canaliculi. This is consistent with the production of carbon dioxide from arginine in the parietal cell canaliculi. Evidence is presented for the decarboxylation of arginine derived from the activation segment of pepsinogen as the source of carbon dioxide for the production of gastric acid. The production of carbon dioxide by the decarboxylation of arginine in the parietal cell canaliculus enables the extracellular hydration of carbon dioxide at the known site of carbonic anhydrase activity. The extracellular production of acid in the canaliculus together with the presence of agmatine helps to explain why the parietal cells are not destroyed during the formation of gastric acid. Agmatine is found in the mucus secreting cells of the stomach and its role in acid protection of the stomach is discussed. Anat Rec, 2009. (c) 2008 Wiley-Liss, Inc. PMID:18951509

  18. Isolation of bacteria capable of growth with 2-methylisoborneol and geosmin as the sole carbon and energy sources.

    Science.gov (United States)

    Guttman, Lior; van Rijn, Jaap

    2012-01-01

    Using a relatively simple enrichment technique, geosmin and 2-methylisoborneol (MIB)-biodegrading bacteria were isolated from a digestion basin in an aquaculture unit. Comparison of 16S rRNA gene sequences affiliated one of the three isolates with the Gram-positive genus Rhodococcus, while the other two isolates were found to be closely related to the Gram-negative family Comamonadaceae (Variovorax and Comamonas). Growth rates and geosmin and MIB removal rates by the isolates were determined under aerated and nonaerated conditions in mineral medium containing either of the two compounds as the sole carbon and energy source. All isolates exhibited their fastest growth under aerobic conditions, with generation times ranging from 3.1 to 5.7 h, compared to generation times of up to 19.1 h in the nonaerated flasks. Incubation of the isolates with additional carbon sources caused a significant increase in their growth rates, while removal rates of geosmin and MIB were significantly lower than those for incubation with only geosmin or MIB. By fluorescence in situ hybridization, members of the genera Rhodococcus and Comamonas were detected in geosmin- and MIB-enriched sludge from the digestion basin.

  19. Role of metabolite transporters in source-sink carbon allocation

    OpenAIRE

    Ludewig, Frank; Flügge, Ulf-Ingo

    2013-01-01

    Plants assimilate carbon dioxide during photosynthesis in chloroplasts. Assimilated carbon is subsequently allocated throughout the plant. Generally, two types of organs can be distinguished, mature green source leaves as net photoassimilate exporters, and net importers, the sinks, e.g., roots, flowers, small leaves, and storage organs like tubers. Within these organs, different tissue types developed according to their respective function, and cells of either tissue type are highly compartme...

  20. Role of metabolite transporters in source-sink carbon allocation

    OpenAIRE

    Frank eLudewig; Ulf-Ingo eFlügge

    2013-01-01

    Plants assimilate carbon dioxide during photosynthesis in chloroplasts. Assimilated carbon is subsequently allocated throughout the plant. Generally, two types of organs can be distinguished, mature green source leaves as net photoassimilate exporters, and net importers, the sinks, e.g. roots, flowers, small leaves and storage organs like tubers. Within these organs, different tissue types developed according to their respective function, and cells of either tissue type are highly compartment...

  1. 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...

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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...

  7. Different carbon sources affect PCB accumulation by marine bivalves.

    Science.gov (United States)

    Laitano, M V; Silva Barni, M F; Costa, P G; Cledón, M; Fillmann, G; Miglioranza, K S B; Panarello, H O

    2016-02-01

    Pampean creeks were evaluated in the present study as potential land-based sources of PCB marine contamination. Different carbon and nitrogen sources from such creeks were analysed as boosters of PCB bioaccumulation by the filter feeder bivalve Brachidontes rodriguezii and grazer limpet Siphonaria lessoni. Carbon of different source than marine and anthropogenic nitrogen assimilated by organisms were estimated through their C and N isotopic composition. PCB concentration in surface sediments and mollusc samples ranged from 2.68 to 6.46 ng g(-1) (wet weight) and from 1074 to 4583 ng g(-1) lipid, respectively, reflecting a punctual source of PCB contamination related to a landfill area. Thus, despite the low flow of creeks, they should not be underestimated as contamination vectors to the marine environment. On the other hand, mussels PCB bioaccumulation was related with the carbon source uptake which highlights the importance to consider this factor when studying PCB distribution in organisms of coastal systems.

  8. 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

  9. Ammonia-based feedforward and feedback aeration control in activated sludge processes.

    Science.gov (United States)

    Rieger, Leiv; Jones, Richard M; Dold, Peter L; Bott, Charles B

    2014-01-01

    Aeration control at wastewater treatment plants based on ammonia as the controlled variable is applied for one of two reasons: (1) to reduce aeration costs, or (2) to reduce peaks in effluent ammonia. Aeration limitation has proven to result in significant energy savings, may reduce external carbon addition, and can improve denitrification and biological phosphorus (bio-P) performance. Ammonia control for limiting aeration has been based mainly on feedback control to constrain complete nitrification by maintaining approximately one to two milligrams of nitrogen per liter of ammonia in the effluent. Increased attention has been given to feedforward ammonia control, where aeration control is based on monitoring influent ammonia load. Typically, the intent is to anticipate the impact of sudden load changes, and thereby reduce effluent ammonia peaks. This paper evaluates the fundamentals of ammonia control with a primary focus on feedforward control concepts. A case study discussion is presented that reviews different ammonia-based control approaches. In most instances, feedback control meets the objectives for both aeration limitation and containment of effluent ammonia peaks. Feedforward control, applied specifically for switching aeration on or off in swing zones, can be beneficial when the plant encounters particularly unusual influent disturbances.

  10. 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

  11. 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...

  12. 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

  13. Carbon Sources for Polyhydroxyalkanoates and an Integrated Biorefinery

    Directory of Open Access Journals (Sweden)

    Guozhan Jiang

    2016-07-01

    Full Text Available 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.

  14. 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

  15. 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.

  16. Influence of aeration modes on leachate characteristic of landfills that adopt the aerobic-anaerobic landfill method.

    Science.gov (United States)

    Wu, Chuanfu; Shimaoka, Takayuki; Nakayama, Hirofumi; Komiya, Teppei; Chai, Xiaoli; Hao, Yongxia

    2014-01-01

    As far as the optimal design, operation, and field application of the Aerobic-Anaerobic Landfill Method (AALM) are concerned, it is very important to understand how aeration modes (different combinations of aeration depth and air injection rate) affect the biodegradation of organic carbon and the transformation of nitrogen in landfill solid waste. Pilot-scale lysimeter experiments were carried out under different aeration modes to obtain detailed information regarding the influence of aeration modes on leachate characteristics. Results from these lysimeter experiments revealed that aeration at the bottom layer was the most effective for decomposition of organic carbon when compared with aeration at the surface or middle layers. Moreover, the air injection rate led to different nitrogen transformation patterns, unlike the lesser influence it has on organic carbon decomposition. Effective simultaneous nitrification and denitrification were observed for the aeration mode with a higher air injection rate (=1.0 L/min). On the other hand, the phenomenon of sequenced nitrification and denitrification could be observed when a low air injection rate (=0.5L/min.) was employed. Finally, it is concluded that, for AALM, air injection with a higher air injection rate at the deepest layer near the leachate collection pipe tends to accelerate the stabilization of landfill waste as defined in terms of the enhancement of denitrification as well as organic carbon decomposition.

  17. 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.

  18. 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

  19. 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.

  20. 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.)

  1. Critical review of black carbon and elemental carbon source apportionment in Europe and the United States

    Science.gov (United States)

    Briggs, Nicole L.; Long, Christopher M.

    2016-11-01

    An increasing number of air pollution source apportionment studies in Europe and the United States have focused on the black carbon (BC) fraction of ambient particulate matter (PM) given its linkage with adverse public health and climate impacts. We conducted a critical review of European and US BC source apportionment studies published since 2003. Since elemental carbon (EC) has been used as a surrogate measure of BC, we also considered source apportionment studies of EC measurements. This review extends the knowledge presented in previous ambient PM source apportionment reviews because we focus on BC and EC and critically examine the differences between source apportionment results for different methods and source categories. We identified about 50 BC and EC source apportionment studies that have been conducted in either Europe or the US since 2003, finding a striking difference in the commonly used source apportionment methods between the two regions and variations in the assigned source categories. Using three dominant methodologies (radiocarbon, aethalometer, and macro-tracer methods) that only allow for BC to be broadly apportioned into either fossil fuel combustion or biomass burning source categories, European studies generally support fossil fuel combustion as the dominant ambient BC source, but also show significant biomass burning contributions, in particular in wintertime at non-urban locations. Among US studies where prevailing methods such as chemical mass balance (CMB) and positive matrix factorization (PMF) models have allowed for estimation of more refined source contributions, there are fewer findings showing the significance of biomass burning and variable findings on the relative proportion of BC attributed to diesel versus gasoline emissions. Overall, the available BC source apportionment studies provide useful information demonstrating the significance of both fossil fuel combustion and biomass burning BC emission sources in Europe and the US

  2. 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

  3. Role of metabolite transporters in source-sink carbon allocation.

    Science.gov (United States)

    Ludewig, Frank; Flügge, Ulf-Ingo

    2013-01-01

    Plants assimilate carbon dioxide during photosynthesis in chloroplasts. Assimilated carbon is subsequently allocated throughout the plant. Generally, two types of organs can be distinguished, mature green source leaves as net photoassimilate exporters, and net importers, the sinks, e.g., roots, flowers, small leaves, and storage organs like tubers. Within these organs, different tissue types developed according to their respective function, and cells of either tissue type are highly compartmentalized. Photoassimilates are allocated to distinct compartments of these tissues in all organs, requiring a set of metabolite transporters mediating this intercompartmental transfer. The general route of photoassimilates can be briefly described as follows. Upon fixation of carbon dioxide in chloroplasts of mesophyll cells, triose phosphates either enter the cytosol for mainly sucrose formation or remain in the stroma to form transiently stored starch which is degraded during the night and enters the cytosol as maltose or glucose to be further metabolized to sucrose. In both cases, sucrose enters the phloem for long distance transport or is transiently stored in the vacuole, or can be degraded to hexoses which also can be stored in the vacuole. In the majority of plant species, sucrose is actively loaded into the phloem via the apoplast. Following long distance transport, it is released into sink organs, where it enters cells as source of carbon and energy. In storage organs, sucrose can be stored, or carbon derived from sucrose can be stored as starch in plastids, or as oil in oil bodies, or - in combination with nitrogen - as protein in protein storage vacuoles and protein bodies. Here, we focus on transport proteins known for either of these steps, and discuss the implications for yield increase in plants upon genetic engineering of respective transporters. PMID:23847636

  4. Role of metabolite transporters in source-sink carbon allocation

    Directory of Open Access Journals (Sweden)

    Frank eLudewig

    2013-07-01

    Full Text Available Plants assimilate carbon dioxide during photosynthesis in chloroplasts. Assimilated carbon is subsequently allocated throughout the plant. Generally, two types of organs can be distinguished, mature green source leaves as net photoassimilate exporters, and net importers, the sinks, e.g. roots, flowers, small leaves and storage organs like tubers. Within these organs, different tissue types developed according to their respective function, and cells of either tissue type are highly compartmentalized. Photoassimilates are allocated to distinct compartments of these tissues in all organs, requiring a set of metabolite transporters mediating this intercompartmental transfer.The general route of photoassimilates can be briefly described as follows. Upon fixation of carbon dioxide in chloroplasts of mesophyll cells, triose phosphates either enter the cytosol for mainly sucrose formation or remain in the stroma to form transiently stored starch which is degraded during the night and enters the cytosol as maltose or glucose to be further metabolized to sucrose. In both cases, sucrose enters the phloem for long distance transport or is transiently stored in the vacuole, or can be degraded to hexoses which also can be stored in the vacuole.In the majority of plant species, sucrose is actively loaded into the phloem via the apoplast. Following long distance transport, it is released into sink organs, where it enters cells as source of carbon and energy. In storage organs, sucrose can be stored, or carbon derived from sucrose can be stored as starch in plastids, or as oil in oil bodies, or - in combination with nitrogen - as protein in protein storage vacuoles and protein bodies.Here, we focus on transport proteins known for either of these steps, and discuss the implications for yield increase in plants upon genetic engineering of respective transporters.

  5. 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.

  6. A Carbon Nanotube Electron Source Based Ionization Vacuum Gauge

    Energy Technology Data Exchange (ETDEWEB)

    Changkun Dong; Ganapati Myneni

    2003-10-01

    The results of fabrication and performance of an ionization vacuum gauge using a carbon nanotube (CNT) electron source are presented. The electron source was constructed with multi-wall nanotubes (MWNT), which were grown using thermal chemical vapor deposition (CVD) process. The electron emission of the source was stable in vacuum pressure up to 10-7 Torr, which is better than the metal field emitters. The measurement linearity of the gauge was better than {+-}10% from 10-6 to 10-10 Torr. The gauge sensitivity of 4 Torr-1 was achieved under 50 {micro}A electron emission in nitrogen. The gauge is expected to find applications in vacuum measurements from 10-7 Torr to below 10-11 Torr.

  7. Optical Performance of Carbon-Nanotube Electron Sources

    Science.gov (United States)

    de Jonge, Niels; Allioux, Myriam; Oostveen, Jim T.; Teo, Kenneth B.; Milne, William I.

    2005-05-01

    The figure of merit for the electron optical performance of carbon-nanotube (CNT) electron sources is presented. This figure is given by the relation between the reduced brightness and the energy spread in the region of stable emission. It is shown experimentally that a CNT electron source exhibits a highly stable emission process that follows the Fowler-Nordheim theory for field emission, fixing the relationship among the energy spread, the current, and the radius. The performance of the CNT emitter under realistic operating conditions is compared with state-of-the-art electron point sources. It is demonstrated that the reduced brightness is a function of the tunneling parameter, a measure of the energy spread at low temperatures, only, independent of the geometry of the emitter.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Landfill aeration within the scope of post-closure care and its completion.

    Science.gov (United States)

    Ritzkowski, Marco; Stegmann, Rainer

    2013-10-01

    The time frame required for post-closure care of Municipal Solid Waste (MSW) landfills is often assessed over several decades or centuries. One possibility to significantly shorten this period and, at the same time, improve the emission behavior exists with in situ aeration. Positive effects in connection with this method for biological stabilization have been investigated and published elsewhere. However, until today neither generally accepted monitoring guidelines nor completion criteria have been defined. With the paper on hand the authors propose a methodology for the assessment of both, total and remaining stabilization periods for aerated landfills. The central component of this methodology is a carbon balance. The latter is based on a detailed waste characterization in combination with online monitoring of the emissions (gas and leachate). The methodology is exemplarily demonstrated by means of data derived from a full scale project in Northern Germany. Here it could be shown that the predicted aeration period of approximately 6.4years was sufficient to bio-stabilize the landfill. Furthermore, proposals for the completion of landfill aeration are presented. In this connection, carbon balance is of particular importance since the amount of biodegradable organic carbon mainly determines the emission potential. Additional parameters, aiming at a validation of the state of biological stabilization achieved during aeration are proposed and described.

  14. Russia's black carbon emissions: focus on diesel sources

    Science.gov (United States)

    Kholod, Nazar; Evans, Meredydd; Kuklinski, Teresa

    2016-09-01

    Black carbon (BC) is a significant climate forcer with a particularly pronounced forcing effect in polar regions such as the Russian Arctic. Diesel combustion is a major global source of BC emissions, accounting for 25-30 % of all BC emissions. While the demand for diesel is growing in Russia, the country's diesel emissions are poorly understood. This paper presents a detailed inventory of Russian BC emissions from diesel sources. Drawing on a complete Russian vehicle registry with detailed information about vehicle types and emission standards, this paper analyzes BC emissions from diesel on-road vehicles. We use the COPERT emission model (COmputer Programme to calculate Emissions from Road Transport) with Russia-specific emission factors for all types of on-road vehicles. On-road diesel vehicles emitted 21 Gg of BC in 2014: heavy-duty trucks account for 60 % of the on-road BC emissions, while cars represent only 5 % (light commercial vehicles and buses account for the remainder). Using Russian activity data and fuel-based emission factors, the paper also presents BC emissions from diesel locomotives and ships, off-road engines in industry, construction and agriculture, and generators. The study also factors in the role of superemitters in BC emissions from diesel on-road vehicles and off-road sources. The total emissions from diesel sources in Russia are estimated to be 49 Gg of BC and 17 Gg of organic carbon (OC) in 2014. Off-road diesel sources emitted 58 % of all diesel BC in Russia.

  15. Laboratory study of nitrification, denitrification and anammox processes in membrane bioreactors considering periodic aeration.

    Science.gov (United States)

    Abbassi, Rouzbeh; Yadav, Asheesh Kumar; Huang, Shan; Jaffé, Peter R

    2014-09-01

    The possibility of using membrane bioreactors (MBRs) in simultaneous nitrification-anammox-denitrification (SNAD) by considering periodic aeration cycles was investigated. Two separate reactors were operated to investigate the effect of different anammox biomass in the presence of nitrifying and denitrifying biomass on the final nitrogen removal efficiency. The results illustrated that the reactor with higher anammox biomass was more robust to oxygen cycling. Around 98% Total Nitrogen (TN) and 83% Total Organic Carbon (TOC) removal efficiencies were observed by applying one hour aeration over a four-hour cycle. Decreasing the aeration time to 30, 15, and 2 min during a four-hour cycle affected the final TN removal efficiencies. However, the effect of decreasing aeration on the TN removal efficiencies in the reactor with higher anammox biomass was much lower compared to the regular reactor. The nitrous oxide (N2O) emission was a function of aeration as well, and was lower in the reactor with higher anammox biomass. The results of q-PCR analysis confirmed the simultaneous co-existence of nitrifiers, anammox, and denitrifiers in both of the reactors. To simulate the TN removal in these reactors as a function of the aeration time, a new model, based on first order reaction kinetics for both denitrification and anammox was developed and yielded a good agreement with the experimental observations.

  16. 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.

  17. 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.

  18. 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.

  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. 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.

  1. Regional prediction of carbon isotopes in soil carbonates for Asian dust source tracer

    Science.gov (United States)

    Chen, Bing; Cui, Xinjuan; Wang, Yaqiang

    2016-10-01

    Dust particles emitted from deserts and semi-arid lands in northern China cause particulate pollution that increases the burden of disease particularly for urban population in East Asia. The stable carbon isotopes (δ13C) of carbonates in soils and dust aerosols in northern China were investigated. We found that the δ13C of carbonates in surface soils in northern China showed clearly the negative correlation (R2 = 0.73) with Normalized Difference Vegetation Index (NDVI). Using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-derived NDVI, we predicted the regional distribution of δ13C of soil carbonates in deserts, sandy lands, and steppe areas. The predictions show the mean δ13C of -0.4 ± 0.7‰ in soil carbonates in Taklimakan Desert and Gobi Deserts, and the isotope values decrease to -3.3 ± 1.1‰ in sandy lands. The increase in vegetation coverage depletes 13C in soil carbonates, thus the steppe areas are predicted by the lowest δ13C levels (-8.1 ± 1.7‰). The measurements of atmospheric dust samples at eight sites showed that the Asian dust sources were well assigned by the 13C mapping in surface soils. Predicting 13C in large geographical areas with fine resolution offers a cost-effective tracer to monitor dust emissions from sandy lands and steppe areas which show an increasing role in Asian dust loading driven by climate change and human activities.

  2. Autotrophic Nitrogen Removal in a Membrane-Aerated Biofilm Reactor Under Continuous Aeration: A Demonstration

    DEFF Research Database (Denmark)

    Gilmore, Kevin R.; Terada, Akihiko; Smets, Barth F.;

    2013-01-01

    This work describes the successful coupling of partial nitrification (nitritation) and anaerobic ammonium oxidation in a membrane-aerated biofilm reactor (MABR) with continuous aeration. Controlling the relative surface loadings of oxygen versus ammonium prevented complete nitrite oxidation...... nearest to and AnaerAOB furthest from the membrane. Despite the presence of nitrite-oxidizing bacteria, this work demonstrated that these autotrophic processes can be successfully coupled in an MABR with continuous aeration, achieving the benefits of competitive specific N removal rates...

  3. 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.

  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. DESIGN INFORMATION ON FINE PORE AERATION SYSTEMS

    Science.gov (United States)

    Field studies were conducted over several years at municipal wastewater treatment plants employing line pore diffused aeration systems. These studies were designed to produce reliable information on the performance and operational requirements of fine pore devices under process ...

  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. 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.

  8. 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).

  9. 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.

  10. Oxygen transfer in circular surface aeration tanks.

    Science.gov (United States)

    Rao, Achanta Ramakrishna; Patel, Ajey Kumar; Kumar, Bimlesh

    2009-06-01

    Surface aeration systems employed in activated sludge plants are the most energy-intensive units of the plants and typically account for a higher percentage of the treatment facility's total energy use. The geometry of the aeration tank imparts a major effect on the system efficiency. It is said that at optimal geometric conditions, systems exhibits the maximum efficiency. Thus the quantification of the optimal geometric conditions in surface aeration tanks is needed. Optimal geometric conditions are also needed to scale up the laboratory result to the field installation. In the present work, experimental studies have been carried out on baffled and unbaffled circular surface aeration tanks to ascertain the optimal geometric conditions. It is found that no optimal geometric conditions exist for the liquid/water depth in circular surface aeration tanks; however, for design purposes, a standard value has been assumed. Based on the optimal geometric conditions, a scale-up equation has been developed for the baffled circular surface aeration tanks.

  11. Black carbon as a carbon source for young soils in a glacier forefield?

    Science.gov (United States)

    Eckmeier, E.; Pichler, B.; Krebs, R.; Mavris, C.; Egli, M.

    2012-04-01

    Most evident changes in Alpine soils today occur in proglacial areas where existing young soils are continuously developing. Due to climate change, additional areas will become ice-free and subject to weathering and new soil formation. The glacier forefields of the European Alps are continuously exposed since the glaciers reached their maximum expansion in the 1850s. In these proglacial areas, initial soils have started to develop so that they may offer, under optimal conditions, a continuous chronosequence from 0 to 150 year-old soils. The buildup of organic carbon (Corg) in soil is an important factor controlling weathering and the formation of soils. Not only autochthonous but also distant (allochthonous) sources may contribute to the accumulation of soil organic carbon in young soils and surfaces of glacier forefields. Black carbon could be an important component in Alpine soils. However, only little is known about black carbon in very young soils that develop in glacier forefields. The aim of our study was to examine whether black carbon as an allochthonous source of soil organic matter can be detected in the initial soils, and to estimate its relative contribution (as a function of time) to total organic carbon. We investigated surface soil samples (topsoils, A or AO horizon) from 35 sites distributed over the whole proglacial area of Morteratsch, where ideal conditions for a soil chronosequence from 0 to 150 years can be found. Along this sequence, bare till sediments to weakly developed soils (Leptosols) can be encountered. Black carbon concentrations were determined in fine-earth using the benzene polycarboxylic acid (BPCA) marker method as described by Brodowski et al. (2005). We found that the proportion of BPCA-C to total Corg was related to the time since the surface was exposed. The youngest soils (younger than 40 years) contained the highest proportion of BPCA-C (up to 120 g BPCA-C/kg Corg). In these soils, however, the Corg concentrations were very

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. Acetic Acid bacteria: physiology and carbon sources oxidation.

    Science.gov (United States)

    Mamlouk, Dhouha; Gullo, Maria

    2013-12-01

    Acetic acid bacteria (AAB) are obligately aerobic bacteria within the family Acetobacteraceae, widespread in sugary, acidic and alcoholic niches. They are known for their ability to partially oxidise a variety of carbohydrates and to release the corresponding metabolites (aldehydes, ketones and organic acids) into the media. Since a long time they are used to perform specific oxidation reactions through processes called "oxidative fermentations", especially in vinegar production. In the last decades physiology of AAB have been widely studied because of their role in food production, where they act as beneficial or spoiling organisms, and in biotechnological industry, where their oxidation machinery is exploited to produce a number of compounds such as l-ascorbic acid, dihydroxyacetone, gluconic acid and cellulose. The present review aims to provide an overview of AAB physiology focusing carbon sources oxidation and main products of their metabolism.

  18. Trends in the sources and sinks of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Le Quere, Corrine [University of East Anglia, Norwich, United Kingdom; Raupach, Mike [GCP, Canberra, Australia; Canadell, J.G. [CSIRO Marine and Atmospheric Research; Marland, Gregg [ORNL; Bopp, Laurent [National Center for Scientific Research, Gif-sur-Yvette, France; Ciais, Philippe [Laboratoire des Sciences du Climat et de l' Environement, France; Friedlingstein, Pierre [National Center for Scientific Research, Gif-sur-Yvette, France; Viovy, Nicolas [National Center for Scientific Research, Gif-sur-Yvette, France; Conway, T.J. [NOAA, Boulder, CO; Doney, Scott C. [Woods Hole Oceanographic Institution; Feely, R. A. [NOAA Pacific Marine Environmental Laboratory; Foster, Pru [University of Bristol, UK; House, Joanna I [University of Bristol, UK; Prentice, Colin I. [University of Bristol, UK; Gurney, Kevin [Purdue University; Houghton, R.A. [Woods Hole Research Center, Woods Hole, MA; Huntingford, Chris [Center for Ecology and Hydrology, Oxon, England; Levy, Peter E. [Center for Ecology and Hydrology, Midlothian, Scotland; Lomas, M. R. [University of Sheffield; Woodward, F. I. [University of Sheffield; Majkut, Joseph [Princeton University; Sarmiento, Jorge L. [Princeton University; Metzl, Nicolas [University of Paris; Ometto, Jean P [ORNL; Randerson, James T. [University of California, Irvine; Peters, Glen P [Center for International Climate and Energy Research (CICERO), Oslo, Norway; Running, Steven [University of Montana, Missoula; Sitch, Stephen [University of Leeds, UK; Takahashi, Taro [Columbia University; Van der Werf, Guido [Universitate Amsterdam

    2009-12-01

    Efforts to control climate change require the stabilization of atmospheric CO2 concentrations. This can only be achieved through a drastic reduction of global CO2 emissions. Yet fossil fuel emissions increased by 29% between 2000 and 2008, in conjunction with increased contributions from emerging economies, from the production and international trade of goods and services, and from the use of coal as a fuel source. In contrast, emissions from land-use changes were nearly constant. Between 1959 and 2008, 43% of each year's CO2 emissions remained in the atmosphere on average; the rest was absorbed by carbon sinks on land and in the oceans. In the past 50 years, the fraction of CO2 emissions that remains in the atmosphere each year has likely increased, from about 40% to 45%, and models suggest that this trend was caused by a decrease in the uptake of CO2 by the carbon sinks in response to climate change and variability. Changes in the CO2 sinks are highly uncertain, but they could have a significant influence on future atmospheric CO2 levels. It is therefore crucial to reduce the uncertainties.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Suyun [Department of Environmental and Low-Carbon Science, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai (China); Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region (Hong Kong); Selvam, Ammaiyappan [Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region (Hong Kong); Wong, Jonathan W.C., E-mail: jwcwong@hkbu.edu.hk [Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region (Hong Kong)

    2014-02-15

    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 CH{sub 4}/g VS{sub added} 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 CO{sub 2} 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.

  7. Towards a Carbon Nanotube Ionization Source for Planetary Atmosphere Exploration

    Science.gov (United States)

    Oza, A. V.; Leblanc, F.; Berthelier, J. J.; Becker, J.; Coulomb, R.; Gilbert, P.; Hong, N. T.; Lee, S.; Vettier, L.

    2015-12-01

    The characterization of planetary exospheres today, relies on the development of a highly efficient ionization source, due to the scant neutral molecules (n atmospheres provide insight on to physical processes known to occur such as: space weathering, magneto-atmosphere interactions, as well as atmospheric escape mechanisms, all of which are being heavily investigated via current 3D Monte Carlo simulations (Turc et al. 2014, Leblanc et al. 2016 in prep) at LATMOS. Validation of these studies will rely on in-situ observations in the coming decades. Neutral detection strongly depends on electron-impact ionization which via conventional cathode-sources, such as thermal filaments (heated up to 2000 K), may only produce the target ionization essential for energy-measurements with large power consumption. Carbon nanotubes (CNTs) however are ideal low-power, cold cathodes, when subject to moderate electric fields (E ~ 1 MV / m). We present our current device, a small CNT chip, of emission area 15 mm2, emitting electrons that pass through an anode grid and subsequent electrostatic analyzer. The device currently extracts hundreds of µAmperes with applied external voltages ~ -150 Volts, approaching minimum power consumption plasma sputtering the icy regolith with heavy ions and electrons (keV < E < MeV), producing predominately molecular oxygen (Johnson et al. 2002).

  8. 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.

  9. 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.

  10. 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.

  11. Municipal waste stabilization in a reactor with an integrated active and passive aeration system.

    Science.gov (United States)

    Kasinski, Slawomir; Slota, Monika; Markowski, Michal; Kaminska, Anna

    2016-04-01

    To test whether an integrated passive and active aeration system could be an effective solution for aerobic decomposition of municipal waste in technical conditions, a full-scale composting reactor was designed. The waste was actively aerated for 5d, passively aerated for 35 d, and then actively aerated for 5d, and the entire composting process was monitored. During the 45-day observation period, changes in the fractional, morphological and physico-chemical characteristics of the waste at the top of the reactor differed from those in the center of the reactor. The fractional and morphological analysis made during the entire process of stabilization, showed the total reduction of organic matter measured of 82 wt% and 86 wt% at the respective depths. The reduction of organic matter calculated using the results of Lost of Ignition (LOI) and Total Organic Carbon (TOC) showed, respectively, 40.51-46.62% organic matter loss at the top and 45.33-53.39% in the center of the reactor. At the end of the process, moisture content, LOI and TOC at the top were 3.29%, 6.10% and 4.13% higher, respectively, than in the center. The results showed that application of passive aeration in larger scale simultaneously allows the thermophilic levels to be maintained during municipal solid waste composting process while not inhibiting microbial activity in the reactor.

  12. 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.

  13. 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.

  14. 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.

  15. 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 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.

  16. 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.

  17. 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......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...

  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. A study of the ocean source of carbon disulphide

    Science.gov (United States)

    Xie, Huixiang

    1999-11-01

    The environmental importance of atmospheric carbon disulphide (CS 2) is recognised by its potential role as a major precursor of carbonyl Sulphide (OCS). The ocean is believed to emit CS2 to air, but large uncertainty may exist in the assessments of sea-to-air fluxes of this compound partly due to the meager database we currently have for CS2 in the ocean. This work is intended to re-assess the flux estimates and to identify and evaluate the potential Sources for Oceanic CS2. CS2 was measured in both the surface and subsurface waters during three cruises: two in the North Atlantic and one in the Pacific Ocean. All the investigated waters were supersaturated in CS2 relative to the atmosphere. Two distinct types of vertical profiles were observed: one in the cool waters of the North Atlantic, characterized by gradual reduction in CS2 with depth, and another in the warm waters of the North Pacific central are. showing the coexistence of subsurface CS2 and chlorophyll maxima. Solar UV-initiated photochemical reactions were identified as a significant source for oceanic CS2. The photo-production rate of CS2 is positively correlated with absorbance at 350 run, suggesting that the reactions are mediated by coloured dissolved organic matter. Laboratory irradiations confirmed that cysteine and cystine are efficient precursors of CS2 and that OH radicals are likely to be important intermediates. CS2 data were collected from axenic monocultures of six species of marine phytoplankton: Chaetoceros calcitrans, Phaeodactylum tricornutum, Phaeocystis sp., Porphyridium purpureum, Synechococcus sp. and Isochrysis sp. For a period of between two weeks and forty days, substantial accumulation Of CS2 was found in the cultures of C. calcitrans, P. tricornutum and Phaeocystis sp. C. calcitrans has a potential for CS2 production about 10 times higher than P. tricornutum or Phaeocystis sp. CS2 formation was strongly dependent on the growth stage of the cultured species. (Abstract shortened

  20. 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.

  1. USE OF STABLE CARBON ISOTOPE RATIOS OF FATTY ACIDS TO EVALUATE MICROBIAL CARBON SOURCES IN TERRESTRIAL ENVIRONMENTS

    Science.gov (United States)

    We use measurements of the concentration and stable carbon isotopic ratio (D 13C) of individual microbial phospholipid fatty acids (PLFAs) in soils as indicators of live microbial biomass levels and microbial carbon source. We found that intensive sugar cane cultivation leads to ...

  2. 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.

  3. 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…

  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. Aerated bunker discharge of fine dilating powders

    NARCIS (Netherlands)

    Ouwerkerk, C.E.D.; Molenaar, H.J.; Frank, M.J.W.

    1992-01-01

    The discharge rate of coarse powders (mean particle size 500 ¿m) from bunkers without aeration can be described by both empirical relations and theoretical models. In the case of small particles the discharge rate is largely overestimated. As the powder dilates during flow a negative pressure gradie

  6. Ablation Properties of the Carbon-Based Composites Used in Artificial Heat Source Under Fire Accident

    Institute of Scientific and Technical Information of China (English)

    TANG; Xian; HUANG; Jin-ming; ZHOU; Shao-jian; LUO; Zhi-fu

    2012-01-01

    <正>The ablation properties of the carbon-based composites used in artificial heat source under fire accident were investigated by the arc heater. In this work, we tested the carbon-based composites referring to Fig. 1. Their linear/mass ablation ratio and ablation morphologies were studied. The results showed that the carbon-based composites used in artificial heat source behaved well

  7. 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.

  8. 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...

  9. 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...

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

    Science.gov (United States)

    Zhou, Xiaohong; Wu, Yuanyuan; Shi, Hanchang; Song, Yanqing

    2013-02-01

    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 in-situ 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 ha d significantly different oxygen transferperformance; furthermore, the aerators in the samecorridor 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 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.

  11. 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.

  12. Compilation of carbon-14 data

    Energy Technology Data Exchange (ETDEWEB)

    Paasch, R.A.

    1985-07-08

    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.

  13. 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

  14. 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)

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

    Science.gov (United States)

    Xu, Suyun; Selvam, Ammaiyappan; Wong, Jonathan W C

    2014-02-01

    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 VS(added) 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

    ) screw-capped glass bottles under a laminar-flow benchhousedinaC015C176Ccoldroomprocessingfacility.Carewas taken to ensure that the bottles were filled leaving no head space and were tightly sealed in order to minimize contamination from the atmosphere... addressing issues concerning global carbon dynamics. 6,7 Additionally, it has been shown that organic carbon in snow undergoes photochemical reactions, releasing reactive gas-phase species to the overlying atmosphere. 8C010 DespiteitsimportanceinairC0...

  20. 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

  1. CFD model of an aerating hydrofoil

    Science.gov (United States)

    Scott, D.; Sabourin, M.; Beaulieu, S.; Papillon, B.; Ellis, C.

    2014-03-01

    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.

  2. 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.

  3. Sources and sinks of carbon in boreal ecosystems of interior Alaska: A review

    Directory of Open Access Journals (Sweden)

    Thomas A. Douglas

    2014-12-01

    Full Text Available Abstract Boreal ecosystems store large quantities of carbon but are increasingly vulnerable to carbon loss due to disturbance and climate warming. The boreal region in Alaska and Canada, largely underlain by discontinuous permafrost, presents a challenging landscape for itemizing carbon sources and sinks in 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 boreal ecosystems 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 and carbon cycle changes over the next 20 to 50 years. To assist land managers in interior Alaska in adapting and managing for potential changes in the carbon cycle we developed this review paper by incorporating an overview of the climate, ecosystem processes, vegetation, and soil regimes. Our objective is to provide a synthesis of the most current carbon storage estimates and measurements to guide policy and land management decisions on how to best manage carbon sources and sinks. We surveyed estimates of aboveground and belowground carbon stocks for interior Alaska boreal ecosystems and summarized methane and carbon dioxide fluxes. These data have been converted into similar units to facilitate comparison across ecosystem compartments. We identify potential changes in the carbon cycle with climate change and human disturbance. A novel research question is how compounding disturbances affect carbon sources and sinks associated with boreal ecosystem processes. Finally, we provide recommendations to address the challenges facing land managers in efforts to manage carbon cycle processes. The results of this study can be used for carbon cycle management in other locations within the boreal biome which encompasses a broad distribution

  4. 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.)

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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...

  13. 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

  14. 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

  15. 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.

  16. 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

  17. 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...

  18. 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

  19. Tracing organic matter sources and carbon burial in mangrove sediments over the past 160 years

    Science.gov (United States)

    Gonneea, Meagan Eagle; Paytan, Adina; Herrera-Silveira, Jorge A.

    2004-10-01

    Mangrove ecosystems may be a source of organic carbon and nutrients to adjacent coastal systems on one hand and provide a sedimentary sink for organic carbon on the other. The balance between these two functions may be sensitive to both natural and anthropogenically induced variability, yet these effects have not been thoroughly evaluated in mangrove ecosystems. We determine organic matter sources and carbon burial rates over the past 160 years in three lagoons on the Yucatan Peninsula, Mexico. Carbon isotopes and C/N elemental ratios are utilized to trace the three sources contributing to sedimentary organic matter, mangroves, seagrasses and phytoplankton, while nitrogen isotopes are used to elucidate potential post-depositional biogeochemical transformations in mangrove lagoon sediments. All three organic matter sources contribute to organic carbon burial. Phytoplankton and mangroves are the dominant sources of organic matter in lagoon bank sediments and seagrasses are a significant source to central lagoon sediments. Organic carbon burial rates are higher at the lagoon fringes, where mangrove vegetation dominates, than in seagrass-dominated mid-lagoon areas. A reduction in mangrove contribution to the sedimentary organic matter pool concurrent with reduced total organic carbon burial rates is observed in the recent past at all three lagoons studied. Natural cycles in sediment organic matter source over the past 160 years are observed in a high-resolution core. These fluctuations correspond to climatic variability in this region, as recorded in deep-sea foraminiferal assemblages. Additional work is required in order to differentiate between recent anthropogenic perturbations and natural variability in organic carbon sources and burial rates within these ecosystems.

  20. 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

  1. 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.

  2. 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...

  3. Effects of aeration method and aeration rate on greenhouse gas emissions during composting of pig feces in pilot scale.

    Science.gov (United States)

    Jiang, Tao; Li, Guoxue; Tang, Qiong; Ma, Xuguang; Wang, Gang; Schuchardt, Frank

    2015-05-01

    The aim of this study was to uncover ways to mitigate greenhouse gas (GHG) emissions and reduce energy consumption during the composting process. We assessed the effects of different aeration rates (0, 0.18, 0.36, and 0.54 L/(kg dry matter (dm)·min)) and methods (continuous and intermittent) on GHG emissions. Pig feces and corn stalks were mixed at a ratio of 7:1. The composting process lasted for 10 weeks, and the compost was turned approximately every 2 weeks. Results showed that both aeration rate and method significantly affected GHG emissions. Higher aeration rates increased NH3 and N2O losses, but reduced CH4 emissions. The exception is that the CH4 emission of the passive aeration treatment was lower than that of the low aeration rate treatment. Without forced aeration, the CH4 diffusion rates in the center of the piles were very low and part of the CH4 was oxidized in the surface layer. Intermittent aeration reduced NH3 and CH4 losses, but significantly increased N2O production during the maturing periods. Intermittent aeration increased the nitrification/denitrification alternation and thus enhanced the N2O production. Forced aeration treatments had higher GHG emission rates than the passive aeration treatment. Forced aeration accelerated the maturing process, but could not improve the quality of the end product. Compared with continuous aeration, intermittent aeration could increase the O2 supply efficiency and reduced the total GHG emission by 17.8%, and this reduction increased to 47.4% when composting was ended after 36 days.

  4. 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

  5. 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.

  6. Wintertime ecosystem respiration shifts tundra from carbon sink to carbon source at tundra warming experiment

    Science.gov (United States)

    Webb, E.; Schuur, E. A.; Natali, S.; Bracho, R.

    2013-12-01

    Northern latitude ecosystems play a significant role in the global carbon (C) budget due to the roughly 1700 Pg of C stored in permafrost soils. As high latitudes warm, previously frozen C is expected to decompose, thereby increasing CO2 fluxes to the atmosphere and potentially creating a positive feedback to climate warming. While warming has been shown to increase plant C uptake during the growing season, these seasonal C gains may be offset on an annual basis by ecosystem respiration (Reco) during the remaining seven months of the year. Here we present research from the Carbon in Permafrost Experimental Heating Research (CiPEHR) project, a tundra ecosystem warming experiment in interior Alaska. We partitioned the non-growing season into three segments: fall (October 1 until first snow), winter (snow-covered period until spring), and spring (snow depth less than 30cm until melt out). During fall, we measured net ecosystem exchange and Reco using a static flux chamber. In winter, we measured Reco using chamber measurements and soda lime. For spring, we modeled fluxes based on known relationships between snow depth and photosynthetic rate of arctic evergreen species. We found that ecosystem warming caused plants to photosynthesize later in fall and increased C uptake during spring but also enhanced respiration during the long winter. We combined these off-season estimates with measurements from growing season auto-chamber data and found that despite the C gained during the growing season, ecosystem warming resulted in net annual C loss for the two years measured. This annual C loss was dependent on the magnitude of wintertime Reco. Our results indicate that snow depth, soil temperature, and day of season are the major determinants of wintertime Reco. Some climate models predict that arctic ecosystems will experience warmer winters with more snow. Thus, despite increased plant productivity during the growing season, we document that increased wintertime temperatures

  7. 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.

  8. 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.

  9. 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

  10. 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...

  11. 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

  12. 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.

  13. 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.

  14. Carbon Sources to Authigenic Carbonate Rock at Chemosynthetic Communities: Lower Slope of the Gulf of Mexico

    Science.gov (United States)

    Sassen, R.; Jung, W.; Zhang, C.; Defreitas, D. A.

    2004-12-01

    Flux of biogenic methane, crude oil and associated hydrocarbon gases occurs from the deep subsurface to the seafloor, water column, and atmosphere of the Gulf of Mexico slope. Chemosynthetic communities occur at sites of relatively high gas flux, frequently with gas hydrate, but always with authigenic carbonate rock \\(ACR\\). ACR contains carbonate carbon derived from microbial hydrocarbon oxidation that geologically sequesters much fossil carbon, perturbing the carbon cycle. ACR was collected using the ALVIN from sites with chemosynthetic communities in Alaminos Canyon, Atwater Valley, and the Florida Escarpment areas at water depths as much as 3.3 km. Bulk δ 13C was measured and carbonate petrology used to identify carbonate cements, normal marine carbonate, and non-carbonate components such as metal oxides and sulfides. ACR is depleted in 13C. However, the δ 13C of major hydrocarbon types is typically more depleted in 13C than the associated ACR. For example, the mean δ 13C of biogenic methane seeps in the Gulf slope is -74.0\\permil PDB but the lightest bulk ACR measured in the study area is -46.6\\permil PDB. Carbonate cements from hydrocarbon oxidation are shown to enclose skeletal remains of chemosynthetic fauna such as mussels, clams, as well as other fauna characterized by normal marine carbonate \\(\\sim 0\\permil PDB\\). The best explanation of why the δ 13C of ACR does not closely correspond to that of the hydrocarbon starting products is that normal marine carbon dilutes the δ 13C from hydrocarbon oxidation and thus affects the bulk isotopic properties of ACR.

  15. 氧化沟间歇曝气脱氮效果及控制策略的中试研究%INTERMITTENT AERATION INVESTIGATION ON DENITRFICATION AND CONTROL STRATEGY IN A PILOT SCALE OXIDATION DITCH PROCESS

    Institute of Scientific and Technical Information of China (English)

    王涛; 岳波; 张妙月; 扈庆; 朱俊; 李科

    2012-01-01

    One pilot scale oxidation ditch system with front-loaded anaerobic area was investigated on biodemtnfication, adopting the intermittent aeration with continuous flow feeding process. The results demonstrated that different aeration-intermission time caused discrepant range of TN effluent concentration, which was attributed to different time ratio of aeration to intermission; excessive aeration would lead to that cells carbon source was consumed so much that dcnitrification could not go smoothly due to lack of electron donor; but that intermission time lasted too long would resulted in NH/-N excessive accumulation above standard. It had been showed that in the pattern of aeration 1.5 h-intermission 2 h, the effluent concentration of TN and NH/-N could well meet the first-grade B emission standard. Meanwhile auxiliary appropriate aeration control strategy could ensure the quality of effluent and save energy consumption. The continuous aeration experimental study was proceeded in order to discuss intermittent aeration control strategy. The results revealed that ORP and the logarithm of the ratio of NH/-N to NO,-N was good linear correlation, correlation coefficient was 0.987. Utilizing the above relationship combining NH/-N online sensor, the intermittent aeration control process was advanced.%对前置厌氧选择区的中试氧化沟系统,采用连续流间歇曝气方式进行生物脱氮的研究.试验研究表明,不同曝气-停曝时间下出水TN范围不同,其主要与曝气/停曝(时间)比有关;曝气时间过长可能导致细胞内碳源消耗过量而使反硝化因缺乏电子供体受影响,停曝阶段持续过长又可能使NH4+-N积累过多而超标.曝气1.5 h,停曝2h时,出水TN和NH4+-N较好地满足一级B排放标准,该模式辅助适当的曝气控制策略可保证出水水质和节省能耗.为了研究氧化沟间歇曝气控制策略,进行了连续曝气的试验研究,结果表明,ORP与NH4+-N/NO3-N的对数有较好的线

  16. Could 4 degrees warming change Arctic tundra from carbon sink to carbon source?

    Science.gov (United States)

    Torn, M. S.; Abramoff, R. Z.; Chafe, O.; Curtis, J. B.; Smith, L. J.; Wullschleger, S. D.

    2015-12-01

    We have set up a controlled, active warming experiment in permafrost tundra on the North Slope of Alaska. The aim of this micro-warming experiment is to investigate the direct effect of soil warming on microbial decomposition of soil organic matter. We are testing the feasibility of small, short-term, in situ warming that can be run off batteries for distributed deployment and that preserves plant-soil relations and natural variability in wind, temperature, and precipitation. Based on preliminary results, the approach looks promising. One resistance heater cable per plot (25 cm diameter plots) was inserted vertically to 50 cm, spanning the full active layer (maximum thaw depth was 40 cm in 2014). Heaters were turned on August 1, 2015, and heated plots reached the 4ºC warming target within 1-3 days. We are measuring soil microclimate, thaw depth, CO2 and CH4 fluxes, and 14CO2, and microbial composition, as part of the DOE Next Generation Ecosystem Experiments (NGEE-Arctic). Ecosystem respiration increased immediately in the heated plots, and net ecosystem exchange under clear chambers changed from net uptake to net CO2 source in two of the four plots. CH4 flux shifted toward reduced net emissions or greater net uptake in all plots. These rapid responses demonstrate direct changes in decomposition without complications from microbial acclimation, altered community structure or changes in substrate availability. However, future Arctic tundra carbon balance will depend on both short term and long term microbial responses, as well as the links between warming, decomposition, nitrogen mineralization, and plant growth. Thus, we envision that distributed micro-warming plots could be combined with new approaches to aboveground passive warming being developed in NGEE, gradient studies, and modeling.

  17. 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.

  18. Tracer studies on an aerated lagoon.

    Science.gov (United States)

    Broughton, Alistair; Shilton, Andy

    2012-01-01

    The city of Palmerston North, New Zealand, has two aerated lagoons as its secondary treatment facility. Interest about treatment efficiency led to an investigation into the hydraulics in the second lagoon to determine if further optimisation was viable. A tracer study using rhodamine WT was undertaken to ascertain the stimulus response output. Samples were also taken at 24 points within the lagoon to determine the tracer concentration profile throughout the lagoon. The mean residence time was determined to be 39.9 h compared with a theoretical residence time of 55.4 h. Peak concentration of the tracer at the outlet occurred at 0.44 of the mean residence time. The results of the tracer study pointed to 28% of volume being dead space. A subsequent sludge survey indicated that 26% of the design volume of the lagoon was filled with sludge. While the curved geometry of the lagoon did not appear to impact the hydraulics the fact that the first aerator is confined in a relatively smaller area will have locally boosted the mixing energy input in this inlet zone. From interpretation of the tracer response and the tracer distribution profiles it appears that the aerators are mixing the influent into the bulk flow effectively in the front end of the lagoon and that there was no evidence of any substantive short-circuiting path of concentrated tracer around to the outlet. The tracer distribution profiles gave direct insight as to how the tracer was being transported within the pond and should be used more often when conducting tracer studies. Comparison with the literature indicated that the lagoon's hydraulic efficiency was on par with a baffled pond system and it would be expected that addition of several baffles to the lagoon would provide minimal further improvement. PMID:22277219

  19. Mesozoic black shales, source mixing and carbon isotopes

    Science.gov (United States)

    Suan, Guillaume

    2016-04-01

    Over the last decades, considerable attention has been devoted to the paleoenvironmental and biogeochemical significance of Mesozoic black shales. Black shale-bearing successions indeed often display marked changes in the organic carbon isotope composition (δ13Corg), which have been commonly interpreted as evidence for dramatic perturbations of global carbon budgets and CO2 levels. Arguably the majority of these studies have discarded some more "local" explanations when interpreting δ13Corg profiles, most often because comparable profiles occur on geographically large and distant areas. Based on newly acquired data and selected examples from the literature, I will show that the changing contribution of organic components with distinct δ13C signatures exerts a major but overlooked influence of Mesozoic δ13Corg profiles. Such a bias occurs across a wide spectrum of sedimentological settings and ages, as shown by the good correlation between δ13Corg values and proxies of kerogen proportions (such as rock-eval, biomarker, palynofacies and palynological data) recorded in Mesozoic marginal to deep marine successions of Triassic, Jurassic and Cretaceous age. In most of these successions, labile, 12C-enriched amorphous organic matter of marine origin dominates strata deposited under anoxic conditions, while oxidation-resistant, 13C-rich terrestrial particles dominate strata deposited under well-oxygenated conditions. This influence is further illustrated by weathering profiles of Toarcian (Lower Jurassic) black shales from France, where weathered areas dominated by refractory organic matter show dramatic 13C-enrichment (and decreased total organic carbon and pyrite contents) compared to non-weathered portions of the same horizon. The implications of these results for chemostratigraphic correlations and pCO2 reconstructions of Mesozoic will be discussed, as well as strategies to overcome this major bias.

  20. 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.

  1. POSSIBILITY OF USING CARBON ISOTOPES IN THE ASSESSMENT OF THE POLLUTION OF GAS PHASE IN ENVIRONMENTAL RESEARCH

    Directory of Open Access Journals (Sweden)

    Dorota Porowska

    2015-10-01

    Full Text Available Carbon isotope analyses can be used for knowledge and practical purpose. They can be used to assess the genesis of carbon in geochemical environment, and may also be used to indicate environmental contamination by carbon-containing compounds. The aim of the paper is to indicate the possibilities of using carbon isotope composition for interpretation concerning the following elements of the natural environment: atmospheric air, subsurface zone (gases in soils and aeration zone in terms of natural and anthropogenic factors influencing on their quality. This method can be applied universally, when carbon sources are different in isotopic composition.

  2. 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.

  3. 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

  4. 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%.

  5. 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 acet......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...... 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....

  6. 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.

  7. 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

  8. 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

  9. 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...

  10. Enhancement of ultrasonic disintegration of sewage sludge by aeration.

    Science.gov (United States)

    Zhao, He; Zhang, Panyue; Zhang, Guangming; Cheng, Rong

    2016-04-01

    Sonication is an effective way for sludge disintegration, which can significantly improve the efficiency of anaerobic digestion to reduce and recycle use of sludge. But high energy consumption limits the wide application of sonication. In order to improve ultrasonic sludge disintegration efficiency and reduce energy consumption, aeration was introduced. Results showed that sludge disintegration efficiency was improved significantly by combining aeration with ultrasound. The aeration flow rate, gas bubble size, ultrasonic density and aeration timing had impacts on sludge disintegration efficiency. Aeration that used in later stage of ultrasonic irradiation with low aeration flow rate, small gas bubbles significantly improved ultrasonic disintegration sludge efficiency. At the optimal conditions of 0.4 W/mL ultrasonic irradiation density, 30 mL/min of aeration flow rate, 5 min of aeration in later stage and small gas bubbles, ultrasonic sludge disintegration efficiency was increased by 45% and one third of ultrasonic energy was saved. This approach will greatly benefit the application of ultrasonic sludge disintegration and strongly promote the treatment and recycle of wastewater sludge.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Comparing cost and process performance of activated sludge (AS) and biological aerated filters (BAF) over ten years of full sale operation.

    Science.gov (United States)

    Hansen, R; Thogersen, T; Rogalla, F

    2007-01-01

    sludge and the combined biosolids from the AS plant are anaerobically digested, with methane gas being used for generation of heat and power. On-line measurements for the parameters NO3, NO2, NH4, temperature as well as dissolved oxygen (DO) are used for control of aeration and external carbon source (methanol). Dosing of flocculants for P-removal is carried out based on laboratory analysis and jar tests. This paper discusses the experience gained from the plant operation during the last ten years, compiling comparative performance and cost data of the two processes, as well as their optimisation. PMID:17546975

  16. 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...

  17. 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.

  18. 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...

  19. 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.

  20. 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.

  1. Carbon storages in plantation ecosystems in sand source areas of north Beijing, China.

    Directory of Open Access Journals (Sweden)

    Xiuping Liu

    Full Text Available Afforestation is a mitigation option to reduce the increased atmospheric carbon dioxide levels as well as the predicted high possibility of climate change. In this paper, vegetation survey data, statistical database, National Forest Resource Inventory database, and allometric equations were used to estimate carbon density (carbon mass per hectare and carbon storage, and identify the size and spatial distribution of forest carbon sinks in plantation ecosystems in sand source areas of north Beijing, China. From 2001 to the end of 2010, the forest areas increased more than 2.3 million ha, and total carbon storage in forest ecosystems was 173.02 Tg C, of which 82.80 percent was contained in soil in the top 0-100 cm layer. Younger forests have a large potential for enhancing carbon sequestration in terrestrial ecosystems than older ones. Regarding future afforestation efforts, it will be more effective to increase forest area and vegetation carbon density through selection of appropriate tree species and stand structure according to local climate and soil conditions, and application of proper forest management including land-shaping, artificial tending and fencing plantations. It would be also important to protect the organic carbon in surface soils during forest management.

  2. Influence of natural and novel organic carbon sources on denitrification in forest, degraded urban, and restored streams

    Science.gov (United States)

    Organic carbon is important in regulating ecosystem function, and its source and abundance may be altered by urbanization. We investigated shifts in organic carbon quantity and quality associated with urbanization and ecosystem restoration, and its potential effects on denitrific...

  3. 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.

  4. Innovative slow-release organic carbon-source material for groundwater in situ denitrification.

    Science.gov (United States)

    Zhang, Dayi; Zhang, Xu; Wang, Yun; Zhou, Guizhong; Li, Guanghe

    2015-01-01

    Slow-release organic carbon-source (SOC) material, a new kind of electron donor for in situ groundwater denitrification, was prepared and evaluated in this study. With starch as a biologically utilized carbon source and polyvinyl alcohol (PVA) as a frame, this material performed controllable carbon release rates and demonstrated stable behaviour during the simulated denitrification process. Raman spectrum analysis showed that the PVA skeleton formed cross-linking network structures for hydrogen-bonded water molecules reset in low temperatures, and the starchy molecules filled in the interspace of the skeleton to form a two-phase interlocking/disperse phase structure. In a static system, carbon release processes followed the Fickian law with (1.294-6.560)×10(-3) mg g(-1) s(-1/2) as the release coefficient. Under domestication and in situ groundwater simulation conditions, SOC material played a favourable role during denitrification, with 1.049±0.165 as an average carbon-nitrogen ratio. The denitrification process followed the law of zero-order kinetics, while the dynamics parameter kN was 0.563-8.753 gN m(-3) d(-1). Generally, SOC material was suggested to be a potential carbon source (electron donor) suitable for in situ groundwater denitrification.

  5. 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

  6. 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.

  7. North America carbon dioxide sources and sinks: magnitude, attribution, and uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    King, Anthony W.; Hayes, Daniel J.; Huntzinger, Deborah N.; West, Tristram O.; Post, W. M.

    2012-12-01

    North America is both a source and sink of atmospheric CO2. Sources, predominately fossil-fuel combustion in the United States along with contributions from deforestation in Mexico, add CO2 to the atmosphere. Most North America ecosystems, particularly regrowing forests in the United States, are sinks for atmospheric CO2. CO2 is removed from the atmosphere in photosynthesis, converted into biomass and stored as carbon in vegetation, soil and wood products. Fossil-fuel emissions dominate the North American source-sink balance. North America is a net source of atmospheric CO2 with ecosystem sinks balancing approximately 35% of fossil-fuel CO2 emissions from North America.

  8. Glyphosate Utilization as the Source of Carbon: Isolation and Identification of new Bacteria

    Directory of Open Access Journals (Sweden)

    M. Mohsen Nourouzi

    2011-01-01

    Full Text Available Mixed bacteria from oil palm plantation soil (OPS were isolated to investigate their ability to utilize glyphosate as carbon source. Results showed that approximately all of the glyphosate was converted to aminomethyl-phosphonic acid (AMPA (99.5%. It is worthy to note that mixed bacteria were able to degrade only 2% of AMPA to further metabolites. Two bacterial strains i.e. Stenotrophomonas maltophilia and Providencia alcalifaciens were obtained from enrichment culture. Bacterial isolates were cultured individually on glyphosate as a sole carbon source. It was observed that both isolates were able to convert glyphosate to AMPA.

  9. 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.

  10. 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

  11. 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 ? 13C 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 CO2 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 CO2 generated by the dissolution of carbonate rock in soil profile developed on claystone basement.

  12. 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....

  13. 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...

  14. Optimized aeration strategies for nitrogen and phosphorus removal with aerobic granular sludge.

    Science.gov (United States)

    Lochmatter, Samuel; Gonzalez-Gil, Graciela; Holliger, Christof

    2013-10-15

    Biological wastewater treatment by aerobic granular sludge biofilms offers the possibility to combine carbon (COD), nitrogen (N) and phosphorus (P) removal in a single reactor. Since denitrification can be affected by suboptimal dissolved oxygen concentrations (DO) and limited availability of COD, different aeration strategies and COD loads were tested to improve N- and P-removal in granular sludge systems. Aeration strategies promoting alternating nitrification and denitrification (AND) were studied to improve reactor efficiencies in comparison with more classical simultaneous nitrification-denitrification (SND) strategies. With nutrient loading rates of 1.6 gCOD L(-1) d(-1), 0.2 gN L(-1) d(-1), and 0.08 gP L(-1) d(-1), and SND aeration strategies, N-removal was limited to 62.3 ± 3.4%. Higher COD loads markedly improved N-removal showing that denitrification was limited by COD. AND strategies were more efficient than SND strategies. Alternating high and low DO phases during the aeration phase increased N-removal to 71.2 ± 5.6% with a COD loading rate of 1.6 gCOD L(-1) d(-1). Periods of low DO were presumably favorable to denitrifying P-removal saving COD necessary for heterotrophic N-removal. Intermittent aeration with anoxic periods without mixing between the aeration pulses was even more favorable to N-removal, resulting in 78.3 ± 2.9% N-removal with the lowest COD loading rate tested. P-removal was under all tested conditions between 88 and 98%, and was negatively correlated with the concentration of nitrite and nitrate in the effluent (r = -0.74, p < 0.01). With low COD loading rates, important emissions of undesired N2O gas were observed and a total of 7-9% of N left the reactor as N2O. However, N2O emissions significantly decreased with higher COD loads under AND conditions.

  15. 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

  16. 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

  17. 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.

  18. Tracking Nonpoint Source Nitrogen and Carbon in Watersheds of Chesapeake Bay

    Science.gov (United States)

    Kaushal, S.; Pennino, M. J.; Duan, S.; Blomquist, J.

    2012-12-01

    Humans have altered nitrogen and carbon cycles in rivers regionally with important impacts on coastal ecosystems. Nonpoint source nitrogen pollution is a leading contributor to coastal eutrophication and hypoxia. Shifts in sources of carbon impact downstream ecosystem metabolism and fate and transport of contaminants in coastal zones. We used a combination of stable isotopes and optical tracers to investigate fate and transport of nitrogen and carbon sources in tributaries of the largest estuary in the U.S., the Chesapeake Bay. We analyzed isotopic composition of water samples from major tributaries including the Potomac River, Susquehanna River, Patuxent River, and Choptank River during routine and storm event sampling over multiple years. A positive correlation between δ15N-NO3- and δ18O-NO3- in the Potomac River above Washington D.C. suggested denitrification or biological uptake in the watershed was removing agriculturally-derived N during summer months. In contrast, the Patuxent River in Maryland showed elevated δ15N-NO3- (5 - 12 per mil) with no relationship to δ18O-NO3- suggesting the importance of wastewater sources. From the perspective of carbon sources, there were distinct isotopic values of the δ13C-POM of particulate organic matter and fluorescence excitation emission matrices (EEMS) for rivers influenced by their dominant watershed land use. EEMS showed that there were increases in the humic and fulvic fractions of dissolved organic matter during spring floods, particularly in the Potomac River. Stable isotopic values of δ13C-POM also showed rapid depletion suggesting terrestrial carbon "pulses" in the Potomac River each spring. The δ15N-POM peaked to 10 - 15 per mil each spring suggested a potential manure source or result of biological processing within the watershed. Overall, there were considerable changes in sources and transformations of nitrogen and carbon that varied across rivers and that contribute to nitrogen and carbon loads

  19. Interaction between afternoon aeration and tilapia stocking density

    Directory of Open Access Journals (Sweden)

    Francisco Roberto dos Santos Lima

    2016-01-01

    Full Text Available 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 aeration was carried out from 12.00 a.m. up to 18.00 p.m. from the 3rd week until the end of the experiment. Except for the 16-fish tanks, the lowest concentrations of total ammonia nitrogen were found in the tanks with higher density of fish provided with afternoon aeration. Nitrite concentrations were lower in the 8-fish aerated tanks. In intensive system, the afternoon aeration of the fish culture water is an efficient management of water quality to remove gaseous ammonia and nitrite from water, but it is not appropriate to remove hydrogen sulfide from water.

  20. Effect of aeration rate on composting of penicillin mycelial dreg.

    Science.gov (United States)

    Chen, Zhiqiang; Zhang, Shihua; Wen, Qinxue; Zheng, Jun

    2015-11-01

    Pilot scale experiments with forced aeration were conducted to estimate effects of aeration rates on the performance of composting penicillin mycelial dreg using sewage sludge as inoculation. Three aeration rates of 0.15, 0.50 and 0.90L/(min·kg) organic matter (OM) were examined. The principal physicochemical parameters were monitored during the 32day composting period. Results showed that the higher aeration rate of 0.90L/(min·kg) did not corresponded to a longer thermophilic duration and higher rates of OM degradation; but the lower aeration rate of 0.15L/(min·kg) did induce an accumulation of NH4(+)-N contents due to the inhibition of nitrification. On the other hand, aeration rate has little effect on degradation of penicillin. The results show that the longest phase of thermophilic temperatures≥55°C, the maximum NO3(-)-N content and seed germination, and the minimum C/N ratio were obtained with 0.50L/(min·kg) OM. Therefore, aeration rates of 0.50L/(min·kg) OM can be recommended for composting penicillin mycelial dreg.

  1. Stream restoration and sewers impact sources and fluxes of water, carbon, and nutrients in urban watersheds

    Science.gov (United States)

    Pennino, Michael J.; Kaushal, Sujay S.; Mayer, Paul M.; Utz, Ryan M.; Cooper, Curtis A.

    2016-08-01

    An improved understanding of sources and timing of water, carbon, and nutrient fluxes associated with urban infrastructure and stream restoration is critical for guiding effective watershed management globally. We investigated how sources, fluxes, and flowpaths of water, carbon (C), nitrogen (N), and phosphorus (P) shift in response to differences in urban stream restoration and sewer infrastructure. We compared an urban restored stream with two urban degraded streams draining varying levels of urban development and one stream with upland stormwater management systems over a 3-year period. We found that there was significantly decreased peak discharge in response to precipitation events following stream restoration. Similarly, we found that the restored stream showed significantly lower (p exported most carbon, nitrogen, and phosphorus at relatively lower streamflow than the two more urban catchments, which exported most carbon and nutrients at higher streamflow. Annual exports of total carbon (6.6 ± 0.5 kg ha-1 yr-1), total nitrogen (4.5 ± 0.3 kg ha-1 yr-1), and total phosphorus (161 ± 15 kg ha-1 yr-1) were significantly lower in the restored stream compared to both urban degraded streams (p exports. However, nitrate isotope data suggested that 55 ± 1 % of the nitrate in the urban restored stream was derived from leaky sanitary sewers (during baseflow), statistically similar to the urban degraded streams. These isotopic results as well as additional tracers, including fluoride (added to drinking water) and iodide (contained in dietary salt), suggested that groundwater contamination was a major source of urban nutrient fluxes, which has been less considered compared to upland sources. Overall, leaking sewer pipes are a problem globally and our results suggest that combining stream restoration with restoration of aging sewer pipes can be critical to more effectively minimizing urban nonpoint nutrient sources. The sources, fluxes, and flowpaths of groundwater

  2. Production of Medium Chain Length Polyhydroxyalkanoates by Pseudomonas mendocina 0806 from Related and Unrelated Carbon Sources

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Pseudomonas mendocina strain 0806 isolated from oil-contaminated soil was found to produce medium chain length polyhydroxyalkanoates (mcl PHAs).The mcl PHAs consist of monomers with even numbers of carbon atoms such as hydroxyhexanoate (HHx or C6), hydroxyoctanoate (HO or C8), and/or hydroxydecanoate (HD or C10) as major compositions when the strain was grown on unrelated carbon sources such as glucose, citric acid and related carbon sources such as octanoate, myristic acid or oleic acid.While even and odd number hydroxyalkanoate (HA) monomers were synthesized when tridecanoic acid was used as carbon source.The molar ratio of carbon to nitrogen (RC/N) had strong effects on PHA compositions: the strain produced PHAs with 97%-99% (molar ratio) HD (C10) monomer when grown in a glucose ammonium sulfate medium of RC/N40.It was demonstrated that the molar ratio of HO/HD remained constant in the polymers synthesized from media containing a constant RC/N, regardless of the change of glucose concentration.Up to 3.6 g/L cell dry weight containing 45% (mass fraction) PHAs was produced by the strain grown for 48 h in a medium containing 25 g/L glucose with RC/N of 40.

  3. 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

  4. 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.

  5. Silica-Based Carbon Source Delivery for In-situ Bioremediation Enhancement

    Science.gov (United States)

    Zhong, L.; Lee, M. H.; Lee, B.; Yang, S.

    2015-12-01

    Colloidal silica aqueous suspensions undergo viscosity increasing and gelation over time under favorable geochemical conditions. This property of silica suspension can potentially be applied to deliver remedial amendments to the subsurface and establish slow release amendment sources for enhanced remediation. In this study, silica-based delivery of carbon sources for in-situ bioremediation enhancement is investigated. Sodium lactate, vegetable oil, ethanol, and molasses have been studied for the interaction with colloidal silica in aqueous suspensions. The rheological properties of the carbon source amendments and silica suspension have been investigated. The lactate-, ethanol-, and molasses-silica suspensions exhibited controllable viscosity increase and eventually became gels under favorable geochemical conditions. The gelation rate was a function of the concentration of silica, salinity, amendment, and temperature. The vegetable oil-silica suspensions increased viscosity immediately upon mixing, but did not perform gelation. The carbon source release rate from the lactate-, ethanol-, and molasses-silica gels was determined as a function of silica, salinity, amendment concentration. The microbial activity stimulation and in-situ bioremediation enhancement by the slow-released carbon from the amendment-silica gels will be demonstrated in future investigations planned in this study.

  6. 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;

    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...

  7. 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.

  8. 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.

  9. 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

  10. 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...

  11. 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

  12. Removal of pharmaceuticals in aerated biofilters with manganese feeding.

    Science.gov (United States)

    Zhang, Yongjun; Zhu, Hong; Szewzyk, Ulrich; Geissen, Sven Uwe

    2015-04-01

    A tertiary treatment step is required in current wastewater treatment plants to remove trace pollutants and thus to prevent their extensive occurrence in the aquatic environment. In this study, natural MnOx ore and natural zeolite were separately used to pack two lab-scale aerated biofilters, which were operated in approximately 1.5 years for the removal of frequently occurring pharmaceuticals, including carbamazepine (CBZ), diclofenac (DFC), and sulfamethoxazole (SMX), out of synthetic and real secondary effluents. Mn(2+) was added in the feeds to promote the growth of iron/manganese oxidizing bacteria which were recently found to be capable of degrading recalcitrant pollutants. An effective removal (80-90%) of DFC and SMX was observed in both biofilters after adaptation while a significant removal of CBZ was not found. Both biofilters also achieved an effective removal of spiked Mn(2+), but a limited removal of carbon and nitrogen contents. Additionally, MnOx biofilter removed 50% of UV254 from real secondary effluent, indicating a high potential on the removal of aromatic compounds.

  13. 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

  14. Impact of artificial aeration on nitrogen removal from aquaculture wastewater treated by vertical-flow constructed wetland%曝气对垂直流湿地处理水产养殖废水脱氮的影响

    Institute of Scientific and Technical Information of China (English)

    张世羊; 常军军; 高毛林; 李谷

    2015-01-01

    the oxidation conditions, which is beneficial for organic matter degradation and nutrient removal. Nevertheless, more detailed studies on the impact of aeration intensity on treatment performance and the associated relationships with influencing factors are still lacking. In the present study, 7 pilot-scale vertical-flow CWs with different combinations of substrates and plants were configured and then systematically investigated in field for treating low-strength aquaculture wastewater with or without artificial aeration. An attempt to explore the impact of the aeration on nitrogen (N) removal or transformation within wetland bed was made. After a thorough comparison between aerated and non-aerated states investigated simultaneously or by stages, the results were depicted as follows: under the operating conditions characterized by high hydraulic loading(HLR) (mean value 1.85 m/d), short hydraulic retention time(HRT) (mean 4.6 h), strong aeration intensity (air flow rate 30 m3/(m2·d), air-water ratio 16.2:1) and low inflow dissolved oxygen (DO) (mean 2.34 mg/L), nitrification occurred obviously within all the systems no matter with or without aeration. DO replenished from atmospheric reoxygenation and plant roots appeared enough to cover the quantity consumed by nitrification and organic matter degradation. Artificial aeration enhanced the intensity of internal mineralization and nitrification. In virtue of no lack of available carbon source (for instance in the present case, the influent ratio of chemical oxygen demand to nitrogen (COD/N) ranged from 28.4 to 30.6), the probability for denitrification under the aerated state increased compared to the non-aerated state, which finally led to the elevation of purification performance on total N (TN). Nevertheless, if too much DO was presented under the aerated state, denitrification would further be restrained, which would conversely lead to the reduction of removal efficiency on TN. Therefore, for complete

  15. 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.

  16. 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

  17. 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

  18. 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...

  19. 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

  20. 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.

  1. Morphogenesis and production of enzymes by Penicillium echinulatum in response to different carbon sources.

    Science.gov (United States)

    Schneider, Willian Daniel Hahn; dos Reis, Laísa; Camassola, Marli; Dillon, Aldo José Pinheiro

    2014-01-01

    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.

  2. Biotransformation of Meloxicam by Cunninghamella blakesleeana: Significance of Carbon and Nitrogen Source.

    Science.gov (United States)

    Shyam Prasad, Gurram; Narasimha Rao, Kollu; Preethi, Rama; Girisham, Sivasri; Reddy, S M

    2011-01-01

    Influence of carbon and nitrogen source, on biotransformation of meloxicam was studied by employing Cunninghamella blakesleeana NCIM 687 with an aim to achieve maximum transformation of meloxicam and in search of new metabolites. The transformation was confirmed by HPLC and based on LC-MS-MS data and previous reports the metabolites were predicted as 5-hydroxymethyl meloxicam, 5-carboxy meloxicam and a novel metabolite. The quantification of metabolites was performed using HPLC peak areas. The results obtained indicate that glucose as carbon source, ammonium nitrate as nitrogen source, were found to be optimum for maximum transformation of meloxicam. The study suggests the significance of these factors in biotransformation of meloxicam using microbial cultures. The fermentation was scaled up to 1 l level. PMID:22282633

  3. 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.

  4. The potential of carbon and nitrogen isotopes to conservatively discriminate between subsoil sediment sources

    Science.gov (United States)

    Laceby, J. Patrick; Olley, Jon

    2013-04-01

    Moreton Bay, in South East Queensland, Australia, is a Ramsar wetland of international significance. A decline of the bay's ecosystem health has been primarily attributed to sediments and nutrients from catchment sources. Sediment budgets for three catchments indicated gully erosion dominates the supply of sediment in Knapp Creek and the Upper Bremer River whereas erosion from cultivated soils is the primary sediment source in Blackfellow Creek. Sediment tracing with fallout-radionuclides confirmed subsoil erosion processes dominate the supply of sediment in Knapp Creek and the Upper Bremer River whereas in Blackfellow Creek cultivated and subsoil sources contribute >90% of sediments. Other sediment properties are required to determine the relative sediment contributions of channel bank, gully and cultivated sources in these catchments. The potential of total organic carbon (TOC), total nitrogen (TN), and carbon and nitrogen stable isotopes (δ13C, δ15N) to conservatively discriminate between subsoil sediment sources is presented. The conservativeness of these sediment properties was examined through evaluating particle size variations in depth core soil samples and investigating whether they remain constant in source soils over two sampling occasions. Varying conservative behavior and source discrimination was observed. TN in the

  5. 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

  6. Effects of Different Carbon Sources and NaBr-KCI on Synthesis of Ti(C,N)

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Ti(C,N) was synthesized with the starting materi-als of 76.9% titania white and 23.1% carbon black (graphite or activated carbon),or 40% titania white and 60% amylum,with or without 10% NaBr-KCI,dry moulding and carbon embedded firing at 1 300 ℃ and 1 400 ℃ for 3 h,respectively.Phase composition and microstructure of the synthesized Ti (C,N) were analyzed by XRD,SEM and EPMA.Effects of different carbon sources and NaBr-KCl on the synthesis of Ti (C,N) were investigated.The results show that:(1) Ti (C,N) can be synthesized by using carbon black,graphite,activated carbon or amylum as carbon source separately;(2) Additive NaBr-KCI is more fa-vorable for accelerating the carbothdrmal reduction reac-tion using carbon black or amylum as carbon source;(3) In the presence of NaBr-KCl,particle size of the synthesized Ti (C,N) is 5-8 μm using carbon black as carbon source fired at 1 300 ℃ for 3 h,while that is only 1-3 μm using graphite,activated carbon or amy-lum fired at 1 400 ℃ for 3 h.

  7. 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

  8. 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

  9. Australian net (1950s-1990) soil organic carbon erosion is an omitted CO2 source

    Science.gov (United States)

    Chappell, A.; Webb, N.; Viscarra Rossel, R. A.; Bui, E. N.

    2013-12-01

    The debate about agricultural erosion substantially offsetting fossil fuel emissions and acting as an important source or sink of CO2 is informed by studies of water and tillage erosion at the field scale and extrapolated across regions based on gross erosion. We use ';catchment' scale (~25 km2) estimates of 137Cs-derived net (1950s-1990) soil redistribution of all processes (wind, water and tillage) to calculate the soil organic carbon (SOC) net redistribution across Australia. We include the selective removal of SOC at net eroding locations, SOC enrichment of transported sediment and net depositional locations. We show that the total SOC net redistribution for Australia is -4.06 Tg SOC y-1, a net loss of SOC from the terrestrial ecosystem and 2% of the total carbon stock (0-10 cm) of Australia. Assuming the SOC is mineralised, these losses represent 12% of CO2-e emissions from all carbon pools in Australia and a significant source of uncertainty in the carbon budget SOC net redistribution as a proportion (%) of SOC stocks Calculation of soil organic carbon net (1950s-1990) redistribution and its proportion for land use classes across Australia *Using an equal area projection the area of a pixel is approximately 4.53 km x 4.87 km ≈ 22.03 km2 equivalent to 2203 ha

  10. 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.

  11. INVESTIGATIONS INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES

    Science.gov (United States)

    Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. Fine pore diffusers were obtained from five municipal wastewa...

  12. 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.

  13. 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.

  14. 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...

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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...... continuous aeration, could remove more than 5.5 g N/m2/day (at loads up to 8 g N/m2/day) by controlled variation of sequential aeration regimes. Daily averaged ratios of the surficial loads of O2 (oxygen) to NH4+ (ammonium) (LO2/LNH4) were close to 1.73 at this optimum. Real-time quantitative PCR based on 16...

  6. 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.

  7. Fine and ultrafine particulate organic carbon in the Los Angeles basin: Trends in sources and composition.

    Science.gov (United States)

    Shirmohammadi, Farimah; Hasheminassab, Sina; Saffari, Arian; Schauer, James J; Delfino, Ralph J; Sioutas, Constantinos

    2016-01-15

    In this study, PM2.5 and PM0.18 (particles with dporganic carbons) and individual organic compounds. Concentrations of organic compounds were reported and compared with many previous studies in Central LA to quantify the impact of emissions control measurements that have been implemented for vehicular emissions over the past decades in this area. Moreover, a novel hybrid approach of molecular marker-based chemical mass balance (MM-CMB) analysis was conducted, in which a combination of source profiles that were previously obtained from a Positive Matrix Factorization (PMF) model in Central LA, were combined with some traditional source profiles. The model estimated the relative contributions from mobile sources (including gasoline, diesel, and smoking vehicles), wood smoke, primary biogenic sources (including emissions from vegetative detritus, food cooking, and re-suspended soil dust), and anthropogenic secondary organic carbon (SOC). Mobile sources contributed to 0.65 ± 0.25 μg/m(3) and 0.32 ± 0.25 μg/m(3) of PM2.5 OC in Central LA and Anaheim, respectively. Primary biogenic and anthropogenic SOC sources were major contributors to OC concentrations in both size fractions and sites. Un-apportioned OC ("other OC") accounted for an average 8.0 and 26% of PM2.5 OC concentration in Central LA and Anaheim, respectively. A comparison with previous studies in Central LA revealed considerable reduction of EC and OC, along with tracers of mobile sources (e.g. PAHs, hopanes and steranes) as a result of implemented regulations on vehicular emissions. Given the significant reduction of the impacts of mobile sources in the past decade in the LA Basin, the impact of SOC and primary biogenic emissions have a larger relative impact and the new hybrid model allows the impact of these sources to be better quantified.

  8. 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.

  9. [Effects of carbon and nitrogen sources on 5-keto-gluconic acid production].

    Science.gov (United States)

    Tan, Zhilei; Wang, Hongcui; Wei, Yuqiao; Li, Yanyan; Zhong, Cheng; Jia, Shiru

    2014-01-01

    Gluconobacter oxydans is known to oxidize glucose to gluconic acid (GA), and subsequently, to 2-keto-gluconic acid (2KGA) and 5-keto-gluconic acid (5KGA), while 5KGA can be converted to L-(+)-tartaric acid. In order to increase the production of 5KGA, Gluconobacter oxydans HGI-1 that converts GA to 5KGA exclusively was chosen in this study, and effects of carbon sources (lactose, maltose, sucrose, amylum and glucose) and nitrogen sources (yeast extract, fish meal, corn steep liquor, soybean meal and cotton-seed meal) on 5KGA production were investigated. Results of experiment in 500 mL shake-flask show that the highest yield of 5KGA (98.20 g/L) was obtained using 100 g/L glucose as carbon source. 5KGA reached 100.20 g/L, 109.10 g/L, 99.83 g/L with yeast extract, fish meal and corn steep liquor as nitrogen source respectively, among which the optimal nitrogen source was fish meal. The yield of 5KGA by corn steep liquor is slightly lower than that by yeast extract. For the economic reason, corn steep liquor was selected as nitrogen source and scaled up to 5 L stirred-tank fermentor, and the final concentration of 5KGA reached 93.80 g/L, with its maximum volumetric productivity of 3.48 g/(L x h) and average volumetric productivity of 1.56 g/(L x h). The result obtained in this study showed that carbon and nitrogen sourses for large-scale production of 5KGA by Gluconobacter oxydans HGI-1 were glucose and corn steep liquor, respectively, and the available glucose almost completely (85.93%) into 5KGA.

  10. 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

  11. 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.

  12. Chemical ionization mass spectrometry using carbon nanotube field emission electron sources.

    Science.gov (United States)

    Radauscher, Erich J; Keil, Adam D; Wells, Mitch; Amsden, Jason J; Piascik, Jeffrey R; Parker, Charles B; Stoner, Brian R; Glass, Jeffrey T

    2015-11-01

    A novel chemical ionization (CI) source has been developed based on a carbon nanotube (CNT) field emission electron source. The CNT-based electron source was evaluated and compared with a standard filament thermionic electron source in a commercial explosives trace detection desktop mass spectrometer. This work demonstrates the first reported use of a CNT-based ion source capable of collecting CI mass spectra. Both positive and negative modes were investigated. Spectra were collected for a standard mass spectrometer calibration compound, perfluorotributylamine (PFTBA), as well as trace explosives including trinitrotoluene (TNT), Research Department explosive (RDX), and pentaerythritol tetranitrate (PETN). The electrical characteristics, lifetime at operating pressure, and power requirements of the CNT-based electron source are reported. The CNT field emission electron sources demonstrated an average lifetime of 320 h when operated in constant emission mode under elevated CI pressures. The ability of the CNT field emission source to cycle on and off can provide enhanced lifetime and reduced power consumption without sacrificing performance and detection capabilities. Graphical Abstract ᅟ. PMID:26133527

  13. 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.

  14. 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.

  15. Distinct carbon sources indicate strong differentiation between tropical forest and farmland bird communities.

    Science.gov (United States)

    Ferger, Stefan W; Böhning-Gaese, Katrin; Wilcke, Wolfgang; Oelmann, Yvonne; Schleuning, Matthias

    2013-02-01

    The conversion of forest into farmland has resulted in mosaic landscapes in many parts of the tropics. From a conservation perspective, it is important to know whether tropical farmlands can buffer species loss caused by deforestation and how different functional groups of birds respond to land-use intensification. To test the degree of differentiation between farmland and forest bird communities across feeding guilds, we analyzed stable C and N isotopes in blood and claws of 101 bird species comprising four feeding guilds along a tropical forest-farmland gradient in Kenya. We additionally assessed the importance of farmland insectivores for pest control in C(4) crops by using allometric relationships, C stable isotope ratios and estimates of bird species abundance. Species composition differed strongly between forest and farmland bird communities. Across seasons, forest birds primarily relied on C(3) carbon sources, whereas many farmland birds also assimilated C(4) carbon. While C sources of frugivores and omnivores did not differ between forest and farmland communities, insectivores used more C(4) carbon in the farmland than in the forest. Granivores assimilated more C(4) carbon than all other guilds in the farmland. We estimated that insectivorous farmland birds consumed at least 1,000 kg pest invertebrates km(-2) year(-1). We conclude that tropical forest and farmland understory bird communities are strongly separated and that tropical farmlands cannot compensate forest loss for insectivorous forest understory birds. In tropical farmlands, insectivorous bird species provide a quantitatively important contribution to pest control.

  16. 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.

  17. 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

  18. 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...

  19. The influence of carbon sources and morphology on nystatin production by Streptomyces noursei

    DEFF Research Database (Denmark)

    Jonsbu, E.; Mcintyre, Mhairi; Nielsen, Jens

    2002-01-01

    Carbon source nutrition and morphology were examined during cell growth and production of nystatin by Streptomyces noursei ATCC 11455. This strain was able to utilise glucose, fructose, glycerol and soluble starch for cell growth, but failed to grow on media supplemented with galactose, xylose, m...... that this coincided with loss of activity inside the core of the pellets, probably due to diffusion limitation of oxygen or other nutrients....

  20. 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 ...

  1. 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...

  2. 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...

  3. 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...

  4. 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.

  5. 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

  6. [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

  7. [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

  8. Carbon and Nitrogen Sources Influence Tricalcium Phosphate Solubilization and Extracellular Phosphatase Activity by Talaromyces flavus.

    Science.gov (United States)

    Stefanoni Rubio, P J; Godoy, M S; Della Mónica, I F; Pettinari, M J; Godeas, A M; Scervino, J M

    2016-01-01

    The aim of this work was to study phosphate (P) solubilization (and the processes involved in this event) by Talaromyces flavus (BAFC 3125) as a function of carbon and/or nitrogen sources. P solubilization was evaluated in NBRIP media supplemented with different carbon (glucose, sorbitol, sucrose, and fructose) and nitrogen (L-asparagine, urea, ammonium sulfate (AS), and ammonium nitrate (AN) combinations. The highest P solubilization was related to the highest organic acid production (especially gluconic acid) and pH drop for those treatments where glucose was present. Also P solubilization was higher when an inorganic nitrogen source was supplemented to the media when compared to an organic one. Although not being present an organic P source, phosphatase activity was observed. This shows that P mineralization and P solubilization can occur simultaneously, and that P mineralization is not induced by the enzyme substrate. The combination that showed highest P solubilization was for AN-glucose. The highest acid phosphatase activity was for AS-fructose, while for alkaline phosphatase were for AS-fructose and AN-fructose. Acid phosphatase activity was higher than alkaline. P solubilization and phosphatase activity (acid and alkaline) were influenced by the different carbon-nitrogen combinations. A better understanding of phosphate-solubilizing fungi could bring a better use of soil P.

  9. [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

  10. 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.

  11. [Research of controlling condition for aeration stabilization pond dealing with sanitary waste of countryside].

    Science.gov (United States)

    Li, Huai-Zheng; Yao, Shu-Jun; Xu, Zu-Xin; Chen, Wei-Bing

    2012-10-01

    According to research of some problems, such as the hydraulic detention time that aeration stabilization pond deals with sanitary waste of countryside, dissolved oxygen in pond during the process of aeration, the concentration distribution of sludge and different aeration periods affecting on the treatment efficiency, we can acquire good treatment efficiency and energy consumption of economy. The results indicate that under the aeration stabilization pond of this experiment, 4 d is the best hydraulic detention time with this aeration stabilization pond. Time of the discontinuous running aeration should be greater than 15 min. The concentration distribution of sludge can reach equilibrium at each point of aeration stabilization pond between 2 min and 10 min. The best aeration period of dislodging the pollutant is 0.5 h aeration/1.0 h cut-off.

  12. Seasonal variations and aeration effects on water quality improvements and physiological responses of Nymphaea tetragona Georgi.

    Science.gov (United States)

    Lu, Xiao-Ming; Lu, Peng-Zhen; Huang, Min-Sheng; Dai, Ling-Peng

    2013-01-01

    Seasonal variations and aeration effects on water quality improvements and the physiological responses of Nymphaea tetragona Georgi were investigated with mesocosm experiments. Plants were hydroponically cultivated in six purifying tanks (aerated, non-aerated) and the characteristics of the plants were measured. Water quality improvements in purifying tanks were evaluated by comparing to the control tanks. The results showed that continuous aeration affected the plant morphology and physiology. The lengths of the roots, petioles and leaf limbs in aeration conditions were shorter than in non-aeration conditions. Chlorophyll and soluble protein contents of the leaf limbs in aerated tanks decreased, while peroxidase and catalase activities of roots tissues increased. In spring and summer, effects of aeration on the plants were less than in autumn. Total nitrogen (TN) and ammonia nitrogen (NH4(+)-N) in aerated tanks were lower than in non-aerated tanks, while total phosphorus (TP) and dissolved phosphorus (DP) increased in spring and summer. In autumn, effects of aeration on the plants became more significant. TN, NH4(+)-N, TP and DP became higher in aerated tanks than in non-aerated tanks in autumn. This work provided evidences for regulating aeration techniques based on seasonal variations of the plant physiology in restoring polluted stagnant water.

  13. 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

  14. 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

  15. Comprehensive analysis of the metabolome of Pseudomonas putida S12 grown on different carbon sources.

    Science.gov (United States)

    van der Werf, Mariët J; Overkamp, Karin M; Muilwijk, Bas; Koek, Maud M; van der Werff-van der Vat, Bianca J C; Jellema, Renger H; Coulier, Leon; Hankemeier, Thomas

    2008-04-01

    Metabolomics is an emerging, powerful, functional genomics technology that involves the comparative non-targeted analysis of the complete set of metabolites in an organism. We have set-up a robust quantitative metabolomics platform that allows the analysis of 'snapshot' metabolomes. In this study, we have applied this platform for the comprehensive analysis of the metabolite composition of Pseudomonas putida S12 grown on four different carbon sources, i.e. fructose, glucose, gluconate and succinate. This paper focuses on the microbial aspects of analyzing comprehensive metabolomes, and demonstrates that metabolomes can be analyzed reliably. The technical (i.e. sample work-up and analytical) reproducibility was on average 10%, while the biological reproducibility was approximately 40%. Moreover, the energy charge values of the microbial samples generated were determined, and indicated that no biotic or abiotic changes had occurred during sample work-up and analysis. In general, the metabolites present and their concentrations were very similar after growth on the different carbon sources. However, specific metabolites showed large differences in concentration, especially the intermediates involved in the degradation of the carbon sources studied. Principal component discriminant analysis was applied to identify metabolites that are specific for, i.e. not necessarily the metabolites that show those largest differences in concentration, cells grown on either of these four carbon sources. For selected enzymatic reactions, i.e. the glucose-6-phosphate isomerase, triosephosphate isomerase and phosphoglyceromutase reactions, the apparent equilibrium constants (K(app)) were calculated. In several instances a carbon source-dependent deviation between the apparent equilibrium constant (K(app)) and the thermodynamic equilibrium constant (K(eq)) was observed, hinting towards a potential point of metabolic regulation or towards bottlenecks in biosynthesis routes. For glucose-6

  16. Badlands and the Carbon cycle: a significant source of petrogenic organic carbon in rivers and marine environments?

    Science.gov (United States)

    Copard, Yoann; Eyrolle-Boyer, Frederique; Radakovitch, Olivier; Poirel, Alain; Raimbault, Patrick; Lebouteiller, Caroline; Gairoard, Stéphanie; Di-Giovanni, Christian

    2016-04-01

    A key issue in the study of carbon biogeochemical cycle is to well constrain each carbon origin in term of fluxes between all C-reservoirs. From continental surfaces to oceans, rivers convey particulate organic carbon originate from the biomass (biospheric OC) and /or from the sedimentary rocks (petrogenic OC). Existence and importance of this petrogenic OC export to oceans was debated for several decades (see Copard et al., 2007 and ref.), but it is now assumed that 20% of the global carbon export to ocean has a geological origin (Galy et al., 2015). The main current challenge is to constrain the major contributors to this petrogenic OC flux. Amongst the expected sedimentary sources of petrogenic OC in rivers, sedimentary rocks forming badlands can be rightly considered as some viable candidates. Indeed these rocks show a strong erosion rate, may exceed 50 kt km-2 y-1 and in addition, shales, marls and argillaceous rocks, frequently forming badlands (see Nadal-Romero et al., 2011 for the Mediterranean area), contain a significant amount of petrogenic OC (frequently over 0.50 wt. %, Ronov and Yaroshevsky 1976). Our work illustrates the contribution of badlands, mainly distributed within the Durance catchment (a main tributary of the Rhône river), in the petrogenic OC export to the Mediterranean Sea. The approach is based on (i) the use of previous and new data on radiogenic carbon, (ii) bulk organic geochemistry (Rock-Eval pyrolysis), (iii) optical quantification of particulate OM (palynofacies), performed on suspended sediments from the Durance, the Rhône rivers and from small rivers draining the badlands. A mean erosion rate of badlands, previously calculated for instrumented catchments (SOERE Draix-Bléone, Graz et al., 2012) was also applied to the badlands disseminated within the Durance catchment. These different methodologies converge to a petrogenic contribution of the OC export to the Mediterranean Sea close to 30 %. Badlands from the Durance catchment

  17. 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.

  18. 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.

  19. Importance of seagrass as a carbon source for heterotrophic bacteria in a subtropical estuary (Florida Bay)

    Science.gov (United States)

    Williams, Clayton J.; Jaffé, Rudolf; Anderson, William T.; Jochem, Frank J.

    2009-11-01

    A stable carbon isotope approach was taken to identify potential organic matter sources incorporated into biomass by the heterotrophic bacterial community of Florida Bay, a subtropical estuary with a recent history of seagrass loss and phytoplankton blooms. To gain a more complete understanding of bacterial carbon cycling in seagrass estuaries, this study focused on the importance of seagrass-derived organic matter to pelagic, seagrass epiphytic, and sediment surface bacteria. Particulate organic matter (POM), seagrass epiphytic, seagrass ( Thalassia testudinum) leaf, and sediment surface samples were collected from four Florida Bay locations with historically different organic matter inputs, macrophyte densities, and primary productivities. Bulk (observed and those reported previously) and compound-specific bacterial fatty acid δ 13C values were used to determine important carbon sources to the estuary and benthic and pelagic heterotrophic bacteria. The δ 13C values of T. testudinum green leaves with epiphytes removed ranged from -9.9 to -6.9‰. Thalassia testudinum δ 13C values were significant more enriched in 13C than POM, epiphytic, and sediment samples, which ranged from -16.4 to -13.5, -16.2 to -9.6, and -16.7 to -11.0‰, respectively. Bacterial fatty acid δ 13C values (measured for br14:0, 15:0, i15:0, a15:0, br17:0, and 17:0) ranged from -25.5 to -8.2‰. Assuming a -3‰ carbon source fractionation from fatty acid to whole bacteria, pelagic, epiphytic, and sediment bacterial δ 13C values were generally more depleted in 13C than T. testudinum δ 13C values, more enriched in 13C than reported δ 13C values for mangroves, and similar to reported δ 13C values for algae. IsoSource mixing model results indicated that organic matter derived from T. testudinum was incorporated by both benthic and pelagic bacterial communities, where 13-67% of bacterial δ 13C values could arise from consumption of seagrass-derived organic matter. The IsoSource model

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. A fine-focusing x-ray source using carbon-nanofiber field emitter

    Science.gov (United States)

    Sugimoto, W.; Sugita, S.; Sakai, Y.; Goto, H.; Watanabe, Y.; Ohga, Y.; Kita, S.; Ohara, T.

    2010-08-01

    A fine-focusing x-ray source has been constructed employing a field electron emitter prepared by growing carbon-nanofibers (CNFs) on a metal tip. The x-ray source is composed of a CNF field electron emitter, an electrostatic lens, two magnetic lenses, and a W-target for generating x-rays by electron impact. The CNFs provided field electrons with a current density of J ˜5×109 A/m2, which was evaluated with the aid of Fowler-Nordheim theory. The electron beam extracted from the CNF emitter was accelerated to the energies of E =10-25 keV, and then focused by the lenses. By recording the x-ray images of test charts, the optimum resolution of the x-ray source was estimated to be approximately Dx=0.5 μm.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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...

  13. 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

  14. 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

  15. Culture strategies for lipid production using acetic acid as sole carbon source by Rhodosporidium toruloides.

    Science.gov (United States)

    Huang, Xiang-Feng; Liu, Jia-Nan; Lu, Li-Jun; Peng, Kai-Ming; Yang, Gao-Xiang; Liu, Jia

    2016-04-01

    Rhodosporidium toruloides AS 2.1389 was tested using different concentrations of acetic acid as a low-cost carbon source for the production of microbial lipids, which are good raw materials for biodiesel production. It grew and had higher lipid contents in media containing 4-20 g/L acetic acid as the sole carbon source, compared with that in glucose-containing media under the same culture conditions. At acetic acid concentrations as high as 20 g/L and the optimal carbon-to-nitrogen ratio (C/N) of 200 in a batch culture, the highest biomass production was 4.35 g/L, with a lipid content of 48.2%. At acetic acid concentrations as low as 4 g/L, a sequencing batch culture (SBC) with a C/N of 100 increased biomass production to 4.21 g/L, with a lipid content of 38.6%. These results provide usable culture strategies for lipid production by R. toruloides AS 2.1389 when using diverse waste-derived volatile fatty acids.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. BLACK Carbon Emissions from Diesel Sources in the Largest Arctic City: Case Study of Murmansk

    Science.gov (United States)

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

    2014-12-01

    Russia has very little data on its black carbon (BC) emissions. Because Russia makes up such a large share of the Arctic, understanding Russian emissions will improve our understanding of overall BC levels, BC in the Arctic and the link between BC and climate change. This paper provides a detailed, bottom-up inventory of BC emissions from diesel sources in Murmansk, Russia, along with uncertainty estimates associated with these emissions. The research team developed a detailed data collection methodology. The methodology involves assessing the vehicle fleet and activity in Murmansk using traffic, parking lot and driver surveys combined with an existing database from a vehicle inspection station and statistical data. The team also assessed the most appropriate emission factors, drawing from both Russian and international inventory methodologies. The researchers also compared fuel consumption using statistical data and bottom-up fuel calculations. They then calculated emissions for on-road transportation, off-road transportation (including mines), diesel generators, fishing and other sources. The article also provides a preliminary assessment of Russia-wide emissions of black carbon from diesel sources.

  7. 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.

  8. 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

  9. Effects of nitrogen and carbon sources on the production of inulinase from strain Bacillus sp. SG113

    Science.gov (United States)

    Gavrailov, Simeon; Ivanova, Viara

    2016-03-01

    The effects of the carbon and nitrogen substrates on the growth of Bacillus sp. SG113 strain were studied. The use of organic nitrogen sources (peptone, beef extract, yeast extract, casein) leads to rapid cellular growth and the best results for the Bacillus strain were obtained with casein hydrolysate. From the inorganic nitrogen sources studied, the (NH4) 2SO4 proved to be the best nitrogen source. Casein hydrolysate and (NH4) 2SO4 stimulated the invertase synthesis. In the presence of Jerusalem artichoke, onion and garlic extracts as carbon sources the strain synthesized from 6 to 10 times more inulinase.

  10. 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.

  11. 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

    experiments performed in 5 liter bottles indicated that the denitrification rate can be instantaneously increased through the addition of either carbon source. The amount by which the rate was increased depended on the amount of carbon added. In the main experiments performed in a pilot scale alternating...

  12. Carbon Dioxide Capture and Separation Techniques for Gasification-based Power Generation Point Sources

    Energy Technology Data Exchange (ETDEWEB)

    Pennline, H.W.; Luebke, D.R.; Jones, K.L.; Morsi, B.I. (Univ. of Pittsburgh, PA); Heintz, Y.J. (Univ. of Pittsburgh, PA); Ilconich, J.B. (Parsons)

    2007-06-01

    The capture/separation step for carbon dioxide (CO2) from large-point sources is a critical one with respect to the technical feasibility and cost of the overall carbon sequestration scenario. For large-point sources, such as those found in power generation, the carbon dioxide capture techniques being investigated by the in-house research area of the National Energy Technology Laboratory possess the potential for improved efficiency and reduced costs as compared to more conventional technologies. The investigated techniques can have wide applications, but the research has focused on capture/separation of carbon dioxide from flue gas (post-combustion from fossil fuel-fired combustors) and from fuel gas (precombustion, such as integrated gasification combined cycle or IGCC). With respect to fuel gas applications, novel concepts are being developed in wet scrubbing with physical absorption; chemical absorption with solid sorbents; and separation by membranes. In one concept, a wet scrubbing technique is being investigated that uses a physical solvent process to remove CO2 from fuel gas of an IGCC system at elevated temperature and pressure. The need to define an ideal solvent has led to the study of the solubility and mass transfer properties of various solvents. Pertaining to another separation technology, fabrication techniques and mechanistic studies for membranes separating CO2 from the fuel gas produced by coal gasification are also being performed. Membranes that consist of CO2-philic ionic liquids encapsulated into a polymeric substrate have been investigated for permeability and selectivity. Finally, dry, regenerable processes based on sorbents are additional techniques for CO2 capture from fuel gas. An overview of these novel techniques is presented along with a research progress status of technologies related to membranes and physical solvents.

  13. 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...

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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...

  19. 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...

  20. Fault detection and isolation of sensors in aeration control systems.

    Science.gov (United States)

    Carlsson, Bengt; Zambrano, Jesús

    2016-01-01

    In this paper, we consider the problem of fault detection (FD) and isolation in the aeration system of an activated sludge process. For this study, the dissolved oxygen in each aerated zone is assumed to be controlled automatically. As the basis for an FD method we use the ratio of air flow rates into different zones. The method is evaluated in two scenarios: using the Benchmark Simulation Model no. 1 (BSM1) by Monte Carlo simulations and using data from a wastewater treatment plant. The FD method shows good results for a correct and early FD and isolation.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. EFFECT OF CARBON SOURCES ON FORMATION OF ALPHA-AMYLASE BY BACILLUS STEAROTHERMOPHILUS.

    Science.gov (United States)

    WELKER, N E; CAMPBELL, L L

    1963-10-01

    Welker, N. E. (Western Reserve University, Cleveland, Ohio) and L. Leon Campbell. Effect of carbon sources on formation of alpha-amylase by Bacillus stearothermophilus. J. Bacteriol. 86:681-686. 1963.-A chemically defined medium was devised for use in alpha-amylase induction studies. The addition of 0.1% casein hydrolysate to the chemically defined medium permitted growth on fructose, and with glucose, sucrose, maltose, starch, and glycerol it shortened the lag period and increased both the growth rate and the total enzyme produced. Growth did not occur when gluconate, acetate, or succinate were used as carbon sources. alpha-Amylase was produced during the logarithmic phase of growth; the amount produced was inversely proportional to the rate of growth. The poorer the carbon source for growth (glycerol, k = 0.24; glucose, k = 0.26; sucrose, k = 0.42), the higher was the amount of enzyme produced (glycerol, 109 units/ml; glucose, 103 units/ml; sucrose, 45 units/ml). Cells grown on technical-grade maltose (k = 0.26) or starch (k = 0.42) did not conform to this relationship in that unusually large amounts of alpha-amylase were produced (362 and 225 units/ml, respectively). Cells grown on fructose or sucrose had the same growth rate (k = 0.42), but smaller amounts of alpha-amylase were produced on fructose (fructose, 0 to 4 units/ml; sucrose, 45 units/ml). An intracellular alpha-amylase was not detected in Bacillus stearothermophilus.

  7. 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...

  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. 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 ...

  10. 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...

  11. 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

  12. 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...

  13. 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

  14. 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...

  15. 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...

  16. 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.

  17. Effect of cyclic aeration on fouling in submerged membrane bioreactor for wastewater treatment.

    Science.gov (United States)

    Wu, Jun; He, Chengda

    2012-07-01

    Due to the inefficiency of aeration measures in preventing fouling by soluble and colloidal particles. The effect of alternating high/low cyclic aeration mode on the membrane fouling in the submerged membrane bioreactor was studied by comparing to fouling in a constant aeration mode. Results indicated a higher overall fouling rate in the cyclic aeration mode than in the constant aeration. However, a higher percentage of reversible fouling was observed for the cyclic aeration mode. The membrane permeability can be more easily recovered from physical cleaning such as backwashing in the cyclic aeration mode. The activated sludge floc size distribution analysis revealed a floc destruction and re-flocculation processes caused by the alternating high/low aeration. The short high aeration period could prevent the destruction of strong strength bonds within activated sludge flocs. Therefore, less soluble and colloidal material was observed in the supernatant due to the preservation of the strong strength bonds. The weak strength bonds damaged in the high aeration period could be recovered in the re-flocculation process in the low aeration period. The floc destruction and re-flocculation processes were suggested to be the main reason for the low irreversible fouling in the cyclic aeration mode.

  18. 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.

  19. 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

  20. Colored dissolved organic matter in shallow estuaries: relationships between carbon sources and light attenuation

    Science.gov (United States)

    Oestreich, W.K.; Ganju, Neil Kamal; Pohlman, John; Suttles, Steven

    2016-01-01

    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

  1. 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

  2. The sources of atmospheric black carbon at a European gateway to the Arctic.

    Science.gov (United States)

    Winiger, P; Andersson, A; Eckhardt, S; Stohl, A; Gustafsson, Ö

    2016-01-01

    Black carbon (BC) aerosols from incomplete combustion of biomass and fossil fuel contribute to Arctic climate warming. Models-seeking to advise mitigation policy-are challenged in reproducing observations of seasonally varying BC concentrations in the Arctic air. Here we compare year-round observations of BC and its δ(13)C/Δ(14)C-diagnosed sources in Arctic Scandinavia, with tailored simulations from an atmospheric transport model. The model predictions for this European gateway to the Arctic are greatly improved when the emission inventory of anthropogenic sources is amended by satellite-derived estimates of BC emissions from fires. Both BC concentrations (R(2)=0.89, P<0.05) and source contributions (R(2)=0.77, P<0.05) are accurately mimicked and linked to predominantly European emissions. This improved model skill allows for more accurate assessment of sources and effects of BC in the Arctic, and a more credible scientific underpinning of policy efforts aimed at efficiently reducing BC emissions reaching the European Arctic. PMID:27627859

  3. 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

  4. 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...

  5. Electrospun Fibres of Polyhydroxybutyrate Synthesized by Ralstonia eutropha from Different Carbon Sources

    Directory of Open Access Journals (Sweden)

    Victor U. Irorere

    2014-01-01

    Full Text Available The properties of PHB may be affected by the carbon source used in its production and this may affect nanofibres made from this polymer by electrospinning. In this study, P(3-HB was produced from glucose, rapeseed oil, and olive oil by Ralstonia eutropha H16. Cell growth and polymer production were higher in olive or rapeseed oil supplemented media compared to glucose supplemented media. FT-IR, 1H-, 13C-NMR, and ESI/MSn confirmed that the synthesized polymers were P(3-HB. SEM micrograph showed the formation of nanofibres from P(3-HB samples with the fibre diameters dependent on the source of the carbon used in polymer synthesis and the concentration of the polymer in the electrospinning solution. GPC showed that P(3-HB from glucose (G-PHB had a higher molecular weight (7.35×105 gmol−1 compared to P(3-HB from rapeseed (R-PHB and olive (O-PHB oil. Differential scanning calorimetry (DSC showed that the crystallinity of the electrospun polymers reduces with decreasing polymer concentration with R-PHB having lower crystallinity at all concentrations used. These observation shows that more PHB yield can be obtained using either rapeseed or olive oil compared to glucose with glucose producing polymers of higher molecular weight. It also show that electrospinning could be used to reduce the crystallinity of PHB fibres.

  6. 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

  7. Castor oil as secondary carbon source for production of sophorolipids using Starmerella bombicola NRRL Y-17069.

    Science.gov (United States)

    Bajaj, Vinit Kamalkishor; Annapure, Uday S

    2015-01-01

    Sophorolipids (SLs), a prominent member of the biosurfactants family are produced in acidic and/or lactonic form by yeast Starmerella bombicola NRRL Y-17069 when grown on hydrophilic or hydrophobic or both carbon sources. In current study, ricinoleic acid rich castor oil (10%) was used as hydrophobic and glycerol (10%) was used as hydrophilic carbon source. The yields of 24.5 ± 0.25 g/l sophorolipids were analyzed by anthrone and HPLC method which further increased upto 40.24 ± 0.76 g/l sophorolipids using fed batch process at 5L fermenter level. The structures of sophorolipids synthesized on castor oil were elucidated by liquid chromatography-mass spectrometer (LC-MS), (13)C and (1)H NMR. The results indicated that the ricinoleic acid (RA) gets hydroxylated at ω-1 position but incorporated into sophorolipids through already available hydroxyl group at 12(th) position. It resulted in the production of a novel sophorolipids with hydroxyl fatty acid as side chain and has applications as surfactant for novel drug delivery, anti microbial agent, cosmetic ingredient and emulsifier.

  8. 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%

  9. 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%.

  10. 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.

  11. Health effects of carbon-containing particulate matter: focus on sources and recent research program results.

    Science.gov (United States)

    Rohr, Annette; McDonald, Jacob

    2016-02-01

    Air pollution is a complex mixture of gas-, vapor-, and particulate-phase materials comprised of inorganic and organic species. Many of these components have been associated with adverse health effects in epidemiological and toxicological studies, including a broad spectrum of carbonaceous atmospheric components. This paper reviews recent literature on the health impacts of organic aerosols, with a focus on specific sources of organic material; it is not intended to be a comprehensive review of all the available literature. Specific emission sources reviewed include engine emissions, wood/biomass combustion emissions, biogenic emissions and secondary organic aerosol (SOA), resuspended road dust, tire and brake wear, and cooking emissions. In addition, recent findings from large toxicological and epidemiological research programs are reviewed in the context of organic PM, including SPHERES, NPACT, NERC, ACES, and TERESA. A review of the extant literature suggests that there are clear health impacts from emissions containing carbon-containing PM, but difficulty remains in apportioning responses to certain groupings of carbonaceous materials, such as organic and elemental carbon, condensed and gas phases, and primary and secondary material. More focused epidemiological and toxicological studies, including increased characterization of organic materials, would increase understanding of this issue.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. Effect of Carbon Sources on the Catalytic Performance of Ni/β-Mo2C.

    Science.gov (United States)

    Zeng, Li-Zhen; Zhao, Shao-Fei; Li, Wei-Shan

    2015-06-01

    In this paper, Ni/β-Mo2C(S) and Ni/β-Mo2C(G) were prepared from solution-derived precursor with two different carbon sources (starch and glucose) and tested as anodic noble-metal-free catalysts in air-cathode microbial fuel cells (MFCs). The carburized catalyst samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Brunauer-Emmett-Teller (BET). The activity of the electrocatalyst towards the oxidation of several common microbial fermentation products (formate, lactate, and ethanol) was studied for MFC based on Klebsiella pneumoniae conditions. The composite MFC anodes were fabricated, and their catalytic behavior was investigated. With different carbon sources, the crystalline structure does not change and the crystallinity and surface area increase. The electrocatalytic experiments show that the Ni/β-Mo2C(G) gives the better bio- and electrocatalytic performance than Ni/β-Mo2C(S) due to its higher crystallinity and BET surface area.

  17. [Effects of mixed carbon sources on glucose oxidase production by recombinant Pichia pastoris].

    Science.gov (United States)

    Shen, Yina; Gu, Lei; Zhang, Juan; Chen, Jian; Du, Guocheng

    2013-07-01

    Glucose oxidase (GOD) is an important industrial enzyme with many potential applications. In order to increase the production and productivity of GOD by recombinant Pichia pastoris GS115, we investigated the feeding strategies of mixed carbon sources during induction phase, based on results of the optimization of initial cell and methanol concentration on GOD production. The optimal initial cell and methanol concentration were 100 g/L and 18 g/L. During induction phase, the mixed-carbon-sources strategies showed that glycerol, sorbitol or mannitol co-feeding with methanol could enhance GOD production. With mannitol co-feeding (20:1(W/W)), the maximum GOD production and maximum GOD productivity reached 711.3 U/mL and 4.60 U/(mL x h) after an induction period of 156 h. Compared to the control, the enhancements of GOD production and productivity were 66.3% and 67.9%, respectively. Meanwhile, we found an appropriate mannitol co-feeding strategy that would not inhibit the expression of promote. The activity of alcohol oxidase was 8.8 U/g, which was enhanced by 69.2% compared to the control (5.2 U/g). We can use the same optimization process to improve the production of other proteins from recombinant Pichia pastoris by changing the fermentation parameters.

  18. 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.

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. Internal aeration development and the zonation of plants in wetlands

    DEFF Research Database (Denmark)

    Sorrell, Brian Keith

    support many species which have root aeration adaptations but are otherwise unspecialised for aquatic life. Permanent standing water is a much greater challenge for plants, and survival here is restricted to species with special adaptations to their oxygen transport physiology such as the development...

  4. 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)

  5. Methane biofiltration using Autoclaved Aerated Concrete as the carrier material

    NARCIS (Netherlands)

    Ganendra, Giovanni; Mercado-Garcia, Daniel; Hernandez-Sanabria, Emma; Boeckx, P.; Ho, Adrian; Boon, N.

    2015-01-01

    The methane removal capacity of mixed methane-oxidizing bacteria (MOB) culture in a biofilter setup using autoclaved aerated concrete (AAC) as a highly porous carrier material was tested. Batch experiment was performed to optimize MOB immobilization on AAC specimens where optimum methane removal was

  6. 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

  7. Soil organic carbon dust emission: an omitted global source of atmospheric CO2.

    Science.gov (United States)

    Chappell, Adrian; Webb, Nicholas P; Butler, Harry J; Strong, Craig L; McTainsh, Grant H; Leys, John F; Viscarra Rossel, Raphael A

    2013-10-01

    Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO(2)) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and transporting C dust quickly offshore; augmenting the net loss of C from terrestrial systems. However, the contribution of wind erosion to rates of C release and sequestration is poorly understood. Here, we describe how SOC dust emission is omitted from national C accounting, is an underestimated source of CO(2) and may accelerate SOC decomposition. Similarly, long dust residence times in the unshielded atmospheric environment may considerably increase CO(2) emission. We developed a first approximation to SOC enrichment for a well-established dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO(2)-e yr(-1)) and Australian agricultural soils (0.4 Tg CO(2)-e yr(-1)). These amount to underestimates for CO(2) emissions of ≈10% from combined C pools in Australia (year = 2000), ≈5% from Australian Rangelands and ≈3% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission likely represents a considerable underestimate from those nations' C accounts. We suggest that the omission of SOC dust emission from C cycling and C accounting is a significant global source of uncertainty. Tracing the fate of wind-eroded SOC in the dust cycle is therefore essential to quantify the release of CO(2) from SOC dust to the atmosphere and the contribution of SOC deposition to downwind C sinks.

  8. Quantification and radiocarbon source apportionment of black carbon in atmospheric aerosols using the CTO-375 method

    Science.gov (United States)

    Zencak, Zdenek; Elmquist, Marie; Gustafsson, Örjan

    To make progress towards linking the atmosphere and biogeosphere parts of the black carbon (BC) cycle, a chemothermal oxidation method (CTO-375), commonly applied for isolating BC from complex geomatrices such as soils, sediments and aquatic particles, was applied to investigate the BC also in atmospheric particles. Concentrations and 14C-based source apportionment of CTO-375 based BC was established for a reference aerosol (NIST RM-8785) and for wintertime aerosols collected in Stockholm and in a Swedish background area. The results were compared with thermal-optical (OC/EC) measurements. For NIST RM-8785, a good agreement was found between the BC CTO-375 concentration and the reported elemental carbon (EC) concentration measured by the "Speciation Trends Network—National Institute of Occupational Safety and Health" method (EC NIOSH) with BC CTO-375 of 0.054±0.002 g g -1 and EC NIOSH of 0.067±0.008 g g -1. In contrast, there was an average factor of ca. 20 difference between BC CTO-375 and EC NIOSH for the ambient Scandinavian wintertime aerosols, presumably reflecting a combination of BC CTO-375 isolating only the recalcitrant soot-BC portion of the BC continuum and the EC NIOSH metric inadvertently including some intrinsically non-pyrogenic organic matter. Isolation of BC CTO-375 with subsequent off-line radiocarbon analysis yielded fraction modern values (fM) for total organic carbon (TOC) of 0.93 (aerosols from a Swedish background area), and 0.58 (aerosols collected in Stockholm); whereas the fM for BC CTO-375 isolates were 1.08 (aerosols from a Swedish background area), and 0.87 (aerosols collected in Stockholm). This radiocarbon-based source apportionment suggests that contribution from biomass combustion to cold-season atmospheric BC CTO-375 in Stockholm was 70% and in the background area 88%.

  9. 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

  10. 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

  11. Carbon Isotope Ratios Of Carbon Dioxide In The Urban Salt Lake Valley, Utah USA: Source And Long-Term Monitoring Observations

    Science.gov (United States)

    Ehleringer, J.; Lai, C.; Strong, C.; Pataki, D. E.; Bowling, D. R.; Schauer, A. J.; Bush, S.

    2011-12-01

    A high-precision, decadal record of carbon isotope ratios in atmospheric carbon dioxide has been produced for the urbanized Salt Lake Valley, Utah USA. These data complement a similar time series of atmospheric carbon dioxide concentrations for different locations in the same urban region. This isotopic record includes diurnal and nocturnal observations based on flask (IRMS-based) and continuous (TDL-based) measurement systems. These data reveal repeatable diurnal and seasonal variations in the anthropogenic and biogenic carbon sources that can be used to reconstruct different source inputs. As the Salt Lake Valley is an isolated urban region, the impacts of local anthropogenic inputs can be distinguished from regional patterns as measured by NOAA at the rural Wendover monitoring station 200 km to the west of the Salt Lake Valley. Complementary data, such as vehicle exhaust, emission from power plants and household furnaces, plant and soil organic matter, are also provided to quantify the carbon isotope ratios of the predominant anthropogenic and biogenic sources within the Salt Lake Valley. The combined source and long-term observational values will be made freely available and their utility is discussed for modeling efforts including urban metabolism modeling and atmospheric trace gas modeling.

  12. 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.

  13. 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

  14. Effect of spray aeration on organics and nitrogen removal in vertical subsurface flow constructed wetland.

    Science.gov (United States)

    Ding, Yi; Wang, Wei; Song, Xin-Shan; Wang, Gang; Wang, Yu-Hui

    2014-12-01

    The objective of present study was to assess the simultaneous removal of organics and nitrogen by four lab-scale vertical subsurface flow constructed wetlands (V-SFCWs). The emergent plants employed were Canna indica. Five-month experiments showed that the planted and aerated system largely reduced the COD by 95%, NH4 by 88% and total inorganic nitrogen (TIN) by 83%. It outperformed the unplanted or simple aerated system and was much better than non-aerated system. The study provided a strong evidence to support widespread research and application of spray aeration as a low-cost and energy-efficient aeration technology in V-SFCWs.

  15. Study on the restitution coefficient of original total organic carbon for high mature marine source rocks

    Institute of Scientific and Technical Information of China (English)

    QIN Jianzhong; ZHENG Longju; Tenger

    2007-01-01

    On the basis of the results of hydropyrolysis simulations for about 90 different types of immature to mature source rocks selected from about 5 000 marine source rocks in China,along with the natural thermal evolution profiles,the following conclusions were obtained.(1) Total organic carbon (TOC) content of excellent marine source rocks does not change obviously when Ro<0.8% or Ro > 1.3%,and the residual TOC content is decreasing gradually with the maturity increase at 0.8% <Ro< 1.3%.(2) At the high-post mature stage (Ro > 1.3%),the decreased maximums of residual TOC content for the kerogen of sapropel (Ⅰ),Ⅱ1,and Ⅱ are usually 40%,32% and 24%,respectively,and their TOC restitution coefficient is,respectively,1.68,1.48 and 1.32.(3)Both the TOC decreasing amplitude and the restitution coefficient decrease gradually with the decrease of TOC content for the source rocks with low organic matter abundance (usually 0.3% < TOC < 1.0%).The TOC restitution coefficients are,respectively,1.20 and 1.0,when 0.3%<TOC<0.5% and TOC < 0.3%.(4) TOCres.of solid bitumen and shale with high organic matter abundance (TOC > 30%) also require no restitution at the high mature stage.Such kind of TOC restitution is further supported by the coincidence of the decrease of residual TOC with the decreasing of S1 + S2 and the increasing of hydrocarbon quantity during the experimental simulation of hydrocarbon generation and expulsion for marine source rocks (0.3%<TOC&<30%) in natural thermal evolution profiles.

  16. 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.)

  17. 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.

  18. Burial fluxes and source apportionment of carbon in culture areas of Sanggou Bay over the past 200 years

    Institute of Scientific and Technical Information of China (English)

    LIU Sai; HUANG Jiansheng; YANG Qian; YANG Shu; YANG Guipeng; SUN Yao

    2015-01-01

    In this study, we assessed the burial fluxes and source appointment of different forms of carbon in core sediments collected from culture areas in the Sanggou Bay, and preliminarily analyzed the reasons for the greater proportion of inorganic carbon burial fluxes (BFTIC). The average content of total carbon (TC) in the Sanggou Bay was 2.14%. Total organic carbon (TOC) accounted for a small proportion in TC, more than 65% of which derived from terrigenous organic carbon (Ct), and while the proportion of marine-derived organic carbon (Ca) increased significantly since the beginning of large-scale aquaculture. Total inorganic carbon (TIC) accounted for 60%–75%of TC, an average of which was 60%, with a maximum up to 90% during flourishing periods (1880–1948) of small natural shellfish derived from seashells inorganic carbon (Shell-IC). The TC burial fluxes ranged from 31 g/(m2·a) to 895 g/(m2·a) with an average of 227 g/(m2·a), which was dominated by TIC (about 70%). Shell-IC was the main source of TIC and even TC. As the main food of natural shellfish, biogenic silica (BSi) negatively correlated with BFTIC through affecting shellfish breeding. BFTIC of Sta. S1, influenced greatly by the Yellow Sea Coastal Current, had a certain response to Pacific Decadal Oscillation (PDO) in some specific periods.

  19. The mitochondrial protein Mcu1 plays important roles in carbon source utilization, filamentation, and virulence in Candida albicans.

    Science.gov (United States)

    Guan, Guobo; Wang, Haitao; Liang, Weihong; Cao, Chengjun; Tao, Li; Naseem, Shamoon; Konopka, James B; Wang, Yue; Huang, Guanghua

    2015-08-01

    The fungus Candida albicans is both a pathogen and a commensal in humans. The ability to utilize different carbon sources available in diverse host niches is vital for both commensalism and pathogenicity. N-acetylglucosamine (GlcNAc) is an important signaling molecule as well as a carbon source in C. albicans. Here, we report the discovery of a novel gene MCU1 essential for GlcNAc utilization. Mcu1 is located in mitochondria and associated with multiple energy- and metabolism-related proteins including Por1, Atp1, Pet9, and Mdh1. Consistently, inactivating Por1 impaired GlcNAc utilization as well. Deletion of MCU1 also caused defects in utilizing non-fermentable carbon sources and amino acids. Furthermore, MCU1 is required for filamentation in several inducing conditions and virulence in a mouse systemic infection model. We also deleted TGL99 and GUP1, two genes adjacent to MCU1, and found that the gup1/gup1 mutant exhibited mild defects in the utilization of several carbon sources including GlcNAc, maltose, galactose, amino acids, and ethanol. Our results indicate that MCU1 exists in a cluster of genes involved in the metabolism of carbon sources. Given its importance in metabolism and lack of a homolog in humans, Mcu1 could be a potential target for developing antifungal agents.

  20. 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.

  1. 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

    2016-05-10

    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.

  2. 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.

  3. 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

  4. 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

  5. Radiocarbon based source apportionment of black carbon in the form of PM10 elemental carbon aerosol particles at the Zeppelin Observatory, Svalbard

    Science.gov (United States)

    Winiger, Patrik; Andersson, August; Espen Yttri, Karl; Tunved, Peter; Gustafsson, Örjan

    2015-04-01

    Black carbon (BC) aerosol particles are formed from incomplete combustion of fossil fuel and biomass. Transported into the Arctic, they potentially contributes to climate warming. However, there are still large uncertainties related to the climate effects of BC, including aspects of radiative properties, mixing state of the particles, transport, atmospheric lifetime and sources. The current study aims to reduce source uncertainties by applying a top-down (observational) source-diagnostic isotope approach and comparing these to bottom-up (modeling) emission inventories to better constrain the source types and source regions. The use of natural abundance radiocarbon (Δ14C) is a powerful tool to distinguish between fossil (void of 14C) and biomass (contemporary 14C) combustion sources. Due to the well-defined end-members, 14C-measurements (alone) provide high precision (

  6. Effect of photoperiod, light intensity and carbon sources on biomass and lipid productivities of Isochrysis galbana.

    Science.gov (United States)

    Babuskin, Srinivasan; Radhakrishnan, Kesavan; Babu, Packirisamy Azhagu Saravana; Sivarajan, Meenakshisundaram; Sukumar, Muthusamy

    2014-08-01

    Biomass and lipid productivities of Isochrysis galbana were optimized using nutrients of molasses (4, 8, 12 g l(-1)), glucose (4, 8, 12 g l(-1)), glycerol (4, 8, 12 g l(-1)) and yeast extract (2 g l(-1)). Combinations of carbon sources at different ratios were evaluated in which the alga was grown at three different light intensities (50, 100 and 150 μmol m(-2) s(-1)) under the influence of three different photoperiod cycles (12/12, 18/6 and 24/0 h light/dark). A maximum cell density of 8.35 g l(-1) with 32 % (w/w) lipid was achieved for mixotrophic growth at 100 μmol m(-2) s(-1) and 18/6 h light/dark with molasses/glucose (20:80 w/w). Mixotrophic cultivation using molasses, glucose and glycerol was thus effective for the cultivation of I. galbana.

  7. Effect of Carbon Source with Different Graphitization Degrees on the Synthesis of Diamond

    Institute of Scientific and Technical Information of China (English)

    LIU Wan-Qiang; MA Hong-AN; LI Xiao-Lei; LINAG Zhong-Zhu; LIU Mi-Lan; LI Rui; JIA Xiao-Peng

    2007-01-01

    Using three kinds of graphites with different graphitization degrees as carbon source and Fe-Ni alloy powder as catalyst, the synthesis of diamond crystals is performed in a cubic anvil high-pressure and high-temperature apparatus (SPD-6×1200). Diamond crystals with perfect hexoctahedron shape are successfully synthesized at pressure from 5.0 to 5.5GPa and at temperature from 1570 to 1770K. The synthetic conditions, nucleation, morphology, inclusion and granularity of diamond crystals are studied. The temperature and pressure increase with the increase of the graphitization degree of graphite. The quantity of nucleation and granularity of diamonds decreases with the increase of graphitization degree of graphite under the same synthesis conditions. Moreover, according to the results of the Mossbauer spectrum, the composition of inclusions is mainly Fes C and Fe-Ni alloy phases in diamond crystals synthesized with three kinds of graphites.

  8. 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.

  9. 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

  10. 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.

  11. Production of Polyhydroxybutyrate by Bacillus axaraqunsis BIPC01 using Petrochemical Wastewater as Carbon Source

    Directory of Open Access Journals (Sweden)

    Nasim Mayeli

    2015-08-01

    Full Text Available The aim of this study was to use petrochemical wastewater as the source of carbon for the production of polyhydroxyalkanoates (PHA in an effort to decrease its cost of production. For this purpose, PHA producing bacteria were isolated from the petrochemical wastewater of Bandar Imam, Iran. The purified colonies were screened for PHA by Sudan Black B and Nile Blue A staining. Among positively stained bacteria, the best PHA producer was selected on the basis of cell growth, PHA content and the monomer composition of PHA. The phenotypic and genotypic identification this isolate showed it to be Bacillus axaraqunsis. The PHA was produced at a cell density of about 9.46 g/l of maximum concentration of 6.33g/l l, corresponding to 66% of cell dry weight. These results showed that B. axaraqunsis BIPC01 could be a potent PHA producer using wastewater for industrial purpose and simultaneously reducing the environmental pollution.

  12. New bioemulsifiers produced by Candida lipolytica using D-glucose and babassu oil as carbon sources

    Directory of Open Access Journals (Sweden)

    Vance-Harrop Mabel H.

    2003-01-01

    Full Text Available Candida lipolytica IA 1055 produced extracellular biosurfactants with emulsification activity by fermentation using babassu oil and D-glucose as carbon sources. Natural seawater diluted at 50% supplemented with urea, ammonium sulfate, and phosphate was used as economic basal medium. The best results were achieved with the YSW-B2 medium, which contained urea, ammonium sulfate, and babassu oil and with YSW-B3 medium, which contained urea, ammonium sulfate, phosphate, and babassu oil, kept under fed batch fermentation for 60 hours with 5% of babassu oil. For the two media, the maximum specific growth rates were 0.02 h-1 and 0.04 h-1; the generation times were 34.6 h-1 and 17.3 h-1, and the emulsification activities were 0.666 and 0.158 units, respectively. The molecules of these new bioemulsifiers were contituted of carbohydrates, proteins and lipids.

  13. 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.

  14. 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

  15. Continental scale Antarctic deposition of sulphur and black carbon from anthropogenic and volcanic sources

    Directory of Open Access Journals (Sweden)

    H.-F. Graf

    2010-03-01

    Full Text Available While Antarctica is often described as a pristine environment, there is an increasing awareness of the potential threats from local pollution sources including tourist ships and emissions associated with scientific activities. 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 Erebus volcano. We find that ship emissions, both sulphurous and black carbon, dominate anthropogenic pollution near the ground. Their prevalence is likely to rise dramatically if recent trends in tourism continue.

  16. 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.

  17. 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.

  18. 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.

  19. BIOVENTING - Groundwater Aeration by Discontinuous Oxygen Gas Pulse Injections

    Science.gov (United States)

    Schirmer, M.

    2003-12-01

    Groundwater aeration by discontinuous oxygen gas pulse injections appears to be a promising concept for enhanced natural attenuation of dissolved contaminants that are susceptible for oxygenase enzyme attacks. Oxygen amendments facilitate indigenous microbiota to catabolize groundwater pollutants, such as aromatics, that are considered to be recalcitrant in absence of dissolved oxygen. As a rule, natural attenuation of many pollutants under aerobic conditions is considerably faster than under anaerobic conditions. Thus, enhancing the dissolved oxygen level appears to be worthwhile. In situ aeration of groundwater has been accomplished by air sparging, H2O2-supply, or by utilization of oxygen release compounds. However, continuous aeration of previously anaerobic groundwater is not desirable for several reasons: (a) economic efforts too high, (b) pollutant dislocation towards surface (desired only in air sparging), (c) risk of aquifer clogging (gas clogging, oxidation of ferrous iron, formation of bioslimes). In contrast, discontinuous oxygen gas sparging provides only for periodical groundwater aeration which is followed by microaerobic and suboxic conditions. Microaerobic conditions can prevail spatially (e.g., at plume fringes or within biofilms) or temporarily (e.g., at discontinuous bioventing). They still allow adapted bacteria to transform environmental pollutants to less toxic compounds, e.g., aromatic ring cleavage after dioxygenasis attack. Ring cleavage products, on the other hand, may be degraded more easily by anaerobic consortia than the initial aromatic compounds, making oxygen depletion periods highly intriguing in regard to an initiation of natural attenuation processes at plume fringes. In our work we outline the effect of oxygen depletion conditions on biodegradation of monchlorobenzene (MCB) as they occur subsequently to temporary aeration periods. For microaerobic conditions, relative to the oxygen supply, a stoichiometric transformation of MCB

  20. 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

  1. 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

  2. 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

  3. The need for “apples-to-apples” comparisons of carbon dioxide source and sink estimates

    Science.gov (United States)

    Hayes, Daniel; Turner, David

    2012-10-01

    The global land-based carbon dioxide (CO2) sink can be derived from the difference between fossil fuel emissions and the sum of estimated increases of CO2 in the atmosphere and in the ocean [Houghton, 2010]. For the purposes of developing policy to limit CO2 emissions, it is necessary to refine scientific understanding of the land CO2 flux in terms of its spatial and temporal patterns, as well as the underlying drivers. Net ecosystem exchange (NEE) is the commonly used measure of the land flux and is defined as the net vertical exchange of CO2 between a specified horizontal surface and the atmosphere above it over a given period of time. NEE estimates are reported from the atmospheric perspective, such that a positive value represents emissions (a land source) and a negative value represents removals (a land sink). This term represents a seemingly simple concept, and it was given a clear definition as one of the key carbon cycle variables by Chapin et al. [2006]. However, considerable confusion still arises around its usage, and the ambiguity is traceable primarily to the suite of different approaches used to estimate it.

  4. 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

  5. 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

  6. Nitrification and denitrification in biological activated carbon filter for treating high ammonia source water

    Institute of Scientific and Technical Information of China (English)

    Jianguang LIU; Xiaojian ZHANG; Zhansheng WANG

    2008-01-01

    Since the ammonia in the effluent of the tradi-tional water purification process could not meet the supply demand, the advanced treatment of a high concentration of NH4+-N micro-polluted source water by biological activated carbon filter (BACF) was tested. The filter was operated in the downflow manner and the results showed that the remov-ing rate of NH4+-N was related to the influent concentration of NH4+-N. Its removing rate could be higher than 95% when influent concentration was under 1.0 mg/L. It could also decrease with the increasing influent concentration when the NH4+-N concentration was in the range from 1.5-to 4.9 mg/L and the dissolved oxygen (DO) in the infuent was under 10 mg/L, and the minimum removing rate could be 30%. The key factor of restricting nitrifcation in BACF was the influent DO. When the influent NH4+-N concentration was high, the DO in water was almost depleted entirely by the nitrifying and hetetrophic bacteria in the depth of 0.4 m filter and the filter layer was divided into aerobic and anoxic zones. The nitrification and degradation of organic matters existed in the aerobic zone, while the denitrification occurred in the anoxic zone. Due to the limited carbon source, the denitrification could not be carried out properly, which led to the accu-mulation of the denitrification intermediates such as NO2-. In addition to the denitrification bacteria, the nitrification and the heterotrophic bacteria existed in the anoxic zone.

  7. Kinetic study of the hydrocarbon generation from marine carbonate source rocks characterization of products of gas and liquid hydrocarbon

    Institute of Scientific and Technical Information of China (English)

    GENG Xinhua; GENG Ansong; XIONG Yongqiang; LIU Jinzhong; ZHANG Haizu; ZHAO Qingfang

    2006-01-01

    The kinetic parameters of hydrocarbon generation from the marine carbonate source rocks were determined and calibrated through kinetic simulating experiment. The kinetic parameters of hydrocarbon generation then were extrapolated to geological condition by using the relative software.The result shows that gaseous hydrocarbons (C1, C2,C3, C4-5) were generated in condition of 150℃<T<220℃(1.0%<Ro <3.0% ). Light hydrocarbons (C6-13)and heavy hydrocarbons ( C13+) were generated in condition of 100 ℃<T<170 ℃ (0.5%<Ro<1.5%). A quantitative reference to examine the natural evolution of hydrocarbon of marine carbonate source rocks can be established through the results. It also provides a new method for evaluating the highly mature marine carbonate source rock more reasonably.

  8. 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.

  9. A NMR-Based Carbon-Type Analysis of Diesel Fuel Blends From Various Sources

    Energy Technology Data Exchange (ETDEWEB)

    Bays, J. Timothy; King, David L.

    2013-05-10

    In collaboration with participants of the Coordinating Research Council (CRC) Advanced Vehicle/Fuels/Lubricants (AVFL) Committee, and project AVFL-19, the characteristics of fuels from advanced and renewable sources were compared to commercial diesel fuels. The main objective of this study was to highlight similarities and differences among the fuel types, i.e. ULSD, renewables, and alternative fuels, and among fuels within the different fuel types. This report summarizes the carbon-type analysis from 1H and 13C{1H} nuclear magnetic resonance spectroscopy (NMR) of 14 diesel fuel samples. The diesel fuel samples come from diverse sources and include four commercial ultra-low sulfur diesel fuels (ULSD), one gas-to-liquid diesel fuel (GTL), six renewable diesel fuels (RD), two shale oil-derived diesel fuels, and one oil sands-derived diesel fuel. Overall, the fuels examined fall into two groups. The two shale oil-derived samples and the oil-sand-derived sample closely resemble the four commercial ultra-low sulfur diesels, with SO1 and SO2 most closely matched with ULSD1, ULSD2, and ULSD4, and OS1 most closely matched with ULSD3. As might be expected, the renewable diesel fuels, with the exception of RD3, do not resemble the ULSD fuels because of their very low aromatic content, but more closely resemble the gas-to-liquid sample (GTL) in this respect. RD3 is significantly different from the other renewable diesel fuels in that the aromatic content more closely resembles the ULSD fuels. Fused-ring aromatics are readily observable in the ULSD, SO, and OS samples, as well as RD3, and are noticeably absent in the remaining RD and GTL fuels. Finally, ULSD3 differs from the other ULSD fuels by having a significantly lower aromatic carbon content and higher cycloparaffinic carbon content. In addition to providing important comparative compositional information regarding the various diesel fuels, this report also provides important information about the capabilities of NMR

  10. Antimicrobial Activity of Carbon Nanoparticles Isolated from Natural Sources against Pathogenic Gram-Negative and Gram-Positive Bacteria

    Directory of Open Access Journals (Sweden)

    Sheena Varghese

    2013-01-01

    Full Text Available This paper describes the isolation of carbon nanoparticles (CNPs from kitchen soot, characterization of the CNPs by UV/visible spectroscopy, SEM and XRD, and their antimicrobial action. The antibacterial activity of the isolated carbon nanoparticles was tested against various pathogenic bacterial strains such as Gram-negative Proteus refrigere and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus and Streptococcus haemolyticus. The inhibition zones were measured, and it was found that the carbon nanoparticles isolated from natural sources are active against these Gram-negative and Gram-positive bacterial strains.

  11. Top-down estimate of a large source of atmospheric carbon monoxide associated with fuel combustion in Asia

    OpenAIRE

    Kasibhatla, P.; Arellano, A.; J. A. Logan; Palmer, P.I.; Novelli, P.

    2002-01-01

    Deriving robust regional estimates of the sources of chemically and radiatively important gases and aerosols to the atmosphere is challenging. Here, we focus on carbon monoxide. Using an inverse modeling methodology, we find that the source of carbon monoxide from fossil-fuel and biofuel combustion in Asia during 1994 was 350–380 Tg yr−1, which is 110–140 Tg yr−1 higher than bottom-up estimates derived using traditional inventory-based approaches. This discrepancy points to an important gap i...

  12. DC modeling and the source of flicker noise in passivated carbon nanotube transistors.

    Science.gov (United States)

    Kim, Sunkook; Kim, Seongmin; Janes, David B; Mohammadi, Saeed; Back, Juhee; Shim, Moonsub

    2010-09-24

    DC and intrinsic low-frequency noise properties of p-channel depletion-mode carbon nanotube field effect transistors (CNT-FETs) are investigated. To characterize the intrinsic noise properties, a thin atomic layer deposited (ALD) HfO(2) gate dielectric is used as a passivation layer to isolate CNT-FETs from environmental factors. The ALD HfO(2) gate dielectric in these high-performance top-gated devices is instrumental in attaining hysteresis-free current-voltage characteristics and minimizes low-frequency noise. Under small drain-source voltage, the carriers in the CNT channel are modulated by the gate electrode and the intrinsic 1/f noise is found to be correlated with charge trapping/detrapping from the oxide substrate as expected. When thermionic emission is the dominant carrier transport mechanism in CNT-FETs under large drain-source voltages, the excess 1/f noise is attributed to the noise stemming from metal-CNT Schottky barrier contacts as revealed by the measurements.

  13. Concentration, sources and flux of dissolved organic carbon of precipitation at Lhasa city, the Tibetan Plateau

    Science.gov (United States)

    Li, C.

    2015-12-01

    Dissolved organic carbon (DOC) plays important role in climate system, but few data are available on the Tibetan Plateau (TP). In this study 89 precipitation samples were collected at Lhasa, the largest city of southern Tibet, from March to December 2013. The average concentration and wet deposition fluxes of DOC was 1.10 mg C/L and 0.62 g C m-2.yr-1, respectively. Seasonally, low DOC concentration and high flux appeared during monsoon period, which were in line with heavy precipitation amount, reflecting dilution effect of precipitation for the DOC. Compared to other regions, the values of Lhasa were lower than those of large cites (e.g. Beijing and Seoul) mainly because of less air pollution of Lhasa. The relationship between DOC and ion analysis showed that DOC of Lhasa was derived mainly from the natural sources, followed by burning activities. Furthermore, △14C value of DOC indicated that fossil combustion contributed around 20% of the precipitation DOC of Lhasa, indicating that the atmosphere of Lhasa has been influenced by vehicle emissions. Therefore, although atmosphere of Lhasa is relatively clean, pollutants emitted from local sources cannot be ignored.

  14. Diamondlike carbon deposition on plastic films by plasma source ion implantation

    CERN Document Server

    Tanaka, T; Shinohara, M; Takagi, T

    2002-01-01

    Application of pulsed high negative voltage (approx 10 mu s 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 N sub 2 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 N sub 2 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 mic...

  15. Sources of carbon monoxide and formaldehyde in North America determined from high-resolution atmospheric data

    Directory of Open Access Journals (Sweden)

    S. M. Miller

    2008-06-01

    Full Text Available We analyze the North American budget for carbon monoxide using data for CO and formaldehyde concentrations from tall towers and aircraft in a model-data assimilation framework. The Stochastic Time-Inverted, Lagrangian Transport model for CO (STILT-CO determines local to regional-scale CO contributions associated with production from fossil fuel combustion, biomass burning, and oxidation of volatile organic compounds (VOCs using an ensemble of Lagrangian particles driven by high resolution assimilated meteorology. In most cases, the model demonstrates high fidelity simulations of hourly surface data from tall towers and point measurements from aircraft, with somewhat less satisfactory performance in coastal regions and when CO from large biomass fires in Alaska and the Yukon Territory influence the continental US.

    Inversions of STILT-CO simulations for CO and formaldehyde show that current inventories of CO emissions from fossil fuel combustion are significantly too high, by almost a factor of three in summer and a factor two in early spring, consistent with recent analyses of data from the INTEX-A aircraft program. Formaldehyde data help to show that sources of CO from oxidation of CH4 and other VOCs represent the dominant sources of CO over North America in summer.

  16. Biosynthetic Pathways of Vibrio succinogenes growing with fumarate as terminal electron acceptor and sole carbon source.

    Science.gov (United States)

    Bronder, M; Mell, H; Stupperich, E; Kröger, A

    1982-05-01

    1. With fumarate as the terminal electron acceptor and either H2 or formate as donor, Vibrio succinogenes could grow anaerobically in a mineral medium using fumarate as the sole carbon source. Both the growth rate and the cell yield were increased when glutamate was also present in the medium. 2. Glutamate was incorporated only into the amino acids of the glutamate family (glutamate, glutamine, proline and arginine) of the protein. The residual cell constituents were synthesized from fumarate. 3. Pyruvate and phosphoenolpyruvate, as the central intermediates of most of the cell constituents, were formed through the action of malic enzyme and phosphoenolpyruvate synthetase. Fructose-1,6-bisphosphate aldolase was present in the bacterium suggesting that this enzyme is involved in carbohydrate synthesis. 4. In the absence of added glutamate the amino acids of the glutamate family were synthesized from fumarate via citrate. The enzymes involved in glutamate synthesis were present. 5. During growth in the presence of glutamate, net reducing equivalents were needed for cell synthesis. Glutamate and not H2 or formate was used as the source of these reducing equivalents. For this purpose part of the glutamate was oxidized to yield succinate and CO2. 6. The alpha-ketoglutarate dehydrogenase involved in this reaction was found to use ferredoxin as the electron acceptor. The ferredoxin of the bacterium was reoxidized by means of a NADP-ferredoxin oxidoreductase. Enzymes catalyzing the reduction of NAD, NADP or ferredoxin by H2 or formate were not detected in the bacterium. PMID:7103660

  17. Global organic carbon emissions from primary sources from 1960 to 2009

    Science.gov (United States)

    Huang, Ye; Shen, Huizhong; Chen, Yilin; Zhong, Qirui; Chen, Han; Wang, Rong; Shen, Guofeng; Liu, Junfeng; Li, Bengang; Tao, Shu

    2015-12-01

    In an attempt to reduce uncertainty, global organic carbon (OC) emissions from a total of 70 sources were compiled at 0.1° × 0.1° resolution for 2007 (PKU-OC-2007) and country scale from 1960 to 2009. The compilation took advantage of a new fuel-consumption data product (PKU-Fuel-2007) and a series of newly published emission factors (EFOC) in developing countries. The estimated OC emissions were 32.9 Tg (24.1-50.6 Tg as interquartile range), of which less than one third was anthropogenic in origin. Uncertainty resulted primarily from variations in EFOC. Asia, Africa, and South America had high emissions mainly because of residential biomass fuel burning or wildfires. Per-person OC emission in rural areas was three times that of urban areas because of the relatively high EFOC of residential solid fuels. Temporal trend of anthropogenic OC emissions depended on rural population, and was influenced primarily by residential crop residue and agricultural waste burning. Both the OC/PM2.5 ratio and emission intensity, defined as quantity of OC emissions per unit of fuel consumption for all sources, of anthropogenic OC followed a decreasing trend, indicating continuous improvement in combustion efficiency and control measures.

  18. Source terms; isolation and radiological consequences of carbon-14 waste in the Swedish SFR repository

    International Nuclear Information System (INIS)

    The source term, isolation capacity, and long-term radiological exposure of 14C from the Swedish underground repository for low and intermediate level waste (SFR) is assessed. The prospective amount of 14C in the repository is assumed to be 5 TBq. Spent ion exchange resins will be the dominant source of 14C. The pore water in the concrete repository is expected to maintain a pH of >10.5 for a period of at least 106 y. The cement matrix of the repository will retain most of the 14CO32- initially present. Bacterial production of CO2 and CH4 from degradation of ion-exchange resins and bitumen may contribute to 14C release to the biosphere. However, CH4 contributes only to a small extent to the overall carbon loss from freshwater ecosystems. The individual doses to local and regional individuals peaked with 5x10-3 and regional individuals peaked with 5x10-3 and 8x10-4 μSv y-1 respectively at about 2.4x104 years. A total leakage of 8.4 GBq of 14C from the repository will cause a total collective dose commitment of 1.1 manSv or 130 manSv TBq-1. (authors)

  19. 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

  20. Aerator Performance Effectiveness to Prevent Cavitation in Steep Channel

    Directory of Open Access Journals (Sweden)

    Yeri Sutopo

    2016-04-01

    Full Text Available The incoming air from the atmosphere into the water flow which reaches the bed of the flow > 7% can prevent the cavitation at the bed of the chute spillway channel. At the time of the concentration of air bubbles in the bed flow cannot naturally reach 7 %, then aerator is required at the bottom of the channel, so that the concentration is increased to > 7%.The purpose of this study was to test the aerator effectiveness in increasing the concentration of air bubbles at the bottom of a steep channel. This study used steep channel whose length is 10 m, width 0.2 m, and height 0.4 m, while slope of steep channel is 20º and25º.The discharge is 20.9 l/s.A set of video cameras was used to take a picture of the movement of air bubbles. A Sony ED210 CCTV whose specifications are: indoor, 1/3 "color CCD, 540 TVL resolution, 0.1 lux was used for documentation purpose. The analysis of air bubbles was conducted using aUlead Video Studio 11 equipped with a ImageJ software version 1.43. The results of this study was on the slope of steep channel bed α = 25°, and Q = 20.9 l/s, at a point 7.2 m from the inlet flume on the condition of artificial air entrainment in the downstream flow region after the first aerator was installed, new aerator unit is not required.

  1. Tracing the sources and spatial distribution of organic carbon in subsoils using a multi-biomarker approach

    Science.gov (United States)

    Angst, Gerrit; John, Stephan; Mueller, Carsten W.; Kögel-Knabner, Ingrid; Rethemeyer, Janet

    2016-07-01

    Soil organic carbon (SOC) from aboveground and belowground sources has rarely been differentiated although it may drive SOC turnover and stabilization due to a presumed differing source dependent degradability. It is thus crucial to better identify the location of SOC from different sources for the parameterization of SOC models, especially in the less investigated subsoils. The aim of this study was to spatially assess contributions of organic carbon from aboveground and belowground parts of beech trees to subsoil organic carbon in a Dystric Cambisol. Different sources of SOC were distinguished by solvent-extractable and hydrolysable lipid biomarkers aided by 14C analyses of soil compartments carbon to the upper subsoil (leaf- and root-affected zone) indicate that supposedly fast-cycling, leaf-derived SOC may still be of considerable importance below the A-horizon. In the deeper subsoil (root-affected zone), roots were an important source of fresh SOC. Simultaneously, strongly increasing apparent 14C ages (3860 yrs BP) indicate considerable contribution of SOC that may be inherited from the Pleistocene parent material.

  2. Theoretical preconditions for optimization of composition and technological parameters of the plaster for walls made of aerated concrete blocks (rus

    Directory of Open Access Journals (Sweden)

    Paruta V.A.

    2012-12-01

    Full Text Available The paper reveals the mechanism of cracking in the "aerated concrete masonry - plaster coating" system, which causes the reduction of cladding’s durability. The temperature deformations in the structure are analyzed. On this basis the theoretical background to optimize the composition and technological parameters of the plaster was developed. The composition of plaster mixtures based on the expanded clay, carbonate, perlite and other fillers was also developed. The proposition that targeted modification of plaster can ensure optimal operation of the "laying-plaster" system is experimentally confirmed.

  3. Fungal Culture Systems for Production of Antioxidant Phenolics Using Pecan Nut Shells as Sole Carbon Source

    Directory of Open Access Journals (Sweden)

    Miguel A. Medina

    2010-01-01

    Full Text Available Problem statement: Many agro-industrial wastes have little or none utilization, when these materials could be a very rich source of several value-added compounds, such as: the pecan nut shells, which contain Antioxidant Phenolic (AP molecules like tannins. Approach: In this study, a bioprocess for the liberation of AP from Pecan Nut Shells (PNS was described. A chemical characterization of raw material was evaluated to determine polyphenolic content of PNS, among other components. Several fungal culture systems were evaluated at 96 h fermentation processes and using PNS as sole carbon source. Solid (SSC and Submerged (SmC fermentations were carried out using three strains of Aspergillus niger. Culture medium was composed of a solid (10-50% and a liquid (90- 50% part in order to complete the 100% of the medium. Results: A high concentration (19% of tannins was found in PNS on a dry basis, from which condensed tannins and their monomers were found as the main fraction (14% of tannins of PNS, also on a dry basis. In the strain selection step, Aspergillus niger GH1 showed better growth on pecan nut shells compared to A. niger PSH strain, therefore, A. niger GH1 was used for later experiments. The highest concentration of AP was obtained with SSC inoculated with spores of A. niger GH1 on the 40% of solids system and in 20% solids system where, among the other systems both presented 114 mg TP g-1 of phenolics liberation at 24 h of fermentation. PNS is an important source of catechin, being this kind of compound which can be liberated in higher proportion compared to other phenolics compounds. Conclusion: This study demonstrated that fermenting PNS represent a good alternative to both use residues and obtaining AP.

  4. Soil aeration status in a lowland wet grassland

    Science.gov (United States)

    Barber, K. R.; Leeds-Harrison, P. B.; Lawson, C. S.; Gowing, D. J. G.

    2004-02-01

    The maintenance or development of plant community diversity in species-rich wet grasslands has been a focus of water management considerations in the UK for the past 20 years. Much attention has been given to the control of water levels in the ditch systems within these wet grassland systems. In this paper we report measurements of aeration status and water-table fluctuation made on a peat soil site at Tadham Moor in Somerset, UK, where water management has focused on the maintenance of wet conditions that often result in flooding in winter and wet soil conditions in the spring and summer. Measurement and modelling of the water-table fluctuation indicates the possibility of variability in the aeration of the root environment and anoxic conditions for much of the winter period and for part of the spring and summer. We have used water content and redox potential measurements to characterize the aeration status of the peat soil. We find that air-filled porosity is related to water-table depth in these situations. Redox potentials in the spring were generally found to be low, implying a reducing condition for nitrate and iron. A significant relationship (p < 0.01) between redox potential and water-table depth exists for data measured at 0.1 m depth, but no relationship could be found for data from 0.4 m depth.

  5. 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.

  6. 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

  7. Soil warming effect on net ecosystem exchange of carbon dioxide during the transition from winter carbon source to spring carbon sink in a temperate urban lawn

    Institute of Scientific and Technical Information of China (English)

    Xiaoping Zhou; Xiaoke Wang; Lei Tong; Hongxing Zhang; Fei Lu; Feixiang Zheng; Peiqiang Hou; Wenzhi Song; Zhiyun Ouyang

    2012-01-01

    The significant wanning in urban environment caused by the combined effects of global warming and heat island has stimulated widely development of urban vegetations.However,it is less known of the climate feedback of urban lawn in warmed environment.Soil warming effect on net ecosystem exchange (NEE) of carbon dioxide during the transition period from winter to spring was investigated in a temperate urban lawn in Beijing,China.The NEE (negative for uptake) under soil warming treatment (temperature was about 5℃ higher than the ambient treatment as a control) was-0.71 μmol/(m2·sec),the ecosytem was a CO2 sink under soil warming treatment,the lawn ecosystem under the control was a CO2 source (0.13 μmol/(m2·sec)),indicating that the lawn ecosystem would provide a negative feedback to global warming.There was no significant effect of soil warming on nocturnal NEE (i.e.,ecosystem respiration),although the soil temperature sensitivity (Q10) of ecosystem respiration under soil warming treatment was 3.86,much lower than that in the control (7.03).The CO2 uptake was significantly increased by soil warming treatment that was attributed to about 100% increase of α (apparent quantum yield) and Amax (maximutn rate of photosynthesis).Our results indicated that the response of photosynthesis in urban lawn is much more sensitive to global warming than respiration in the transition period.

  8. Molasses as a source of carbon dioxide for attracting the malaria mosquitoes Anopheles gambiae and Anopheles funestus

    OpenAIRE

    Mweresa, C. K.; Omusula, P.; Otieno, B.; Loon, van, R.R.; Takken, W.; Mukabana, W.R.

    2014-01-01

    Background. Most odour baits for haematophagous arthropods contain carbon dioxide (CO2). The CO2 is sourced artificially from the fermentation of refined sugar (sucrose), dry ice, pressurized gas cylinders or propane. These sources of CO2 are neither cost-effective nor sustainable for use in remote areas of sub-Saharan Africa. In this study, molasses was evaluated as a potential substrate for producing CO2 used as bait for malaria mosquitoes. Methods. The attraction of laboratory-reared and w...

  9. Sources and Dynamics of Inorganic Carbon within the Upper Reaches of the Xi River Basin, Southwest China

    Science.gov (United States)

    Zou, Junyu

    2016-01-01

    The carbon isotopic composition (δ13C) of dissolved and particulate inorganic carbon (DIC; PIC) was used to compare and analyze the origin, dynamics and evolution of inorganic carbon in two headwater tributaries of the Xi River, Southwest China. Carbonate dissolution and soil CO2 were regarded as the primary sources of DIC on the basis of δ13CDIC values which varied along the Nanpan and Beipan Rivers, from −13.9‰ to 8.1‰. Spatial trends in DIC differed between the two rivers (i.e., the tributaries), in part because factors controlling pCO2, which strongly affected carbonate dissolution, differed between the two river basins. Transport of soil CO2 and organic carbon through hydrologic conduits predominately controlled the levels of pCO2 in the Nanpan River. However, pCO2 along the upper reaches of the Nanpan River also was controlled by the extent of urbanization and industrialization relative to agriculture. DIC concentrations in the highly urbanized upper reaches of the Nanpan River were typical higher than in other carbonate-dominated areas of the upper Xi River. Within the Beipan River, the oxidation of organic carbon is the primary process that maintains pCO2 levels. The pCO2 within the Beipan River was more affected by sulfuric acid from coal industries, inputs from a scenic spot, and groundwater than along the Nanpan River. With regards to PIC, the contents and δ13C values in the Nanpan River were generally lower than those in the Beipan River, indicating that chemical and physical weathering contributes more marine carbonate detritus to the PIC along the Beipan River. The CO2 evasion flux from the Nanpan River was higher than that in the Beipan River, and generally higher than along the middle and lower reaches of the Xi River, demonstrating that the Nanpan River is an important net source of atmospheric CO2 in Southwest China. PMID:27513939

  10. Geochemical identification of coal-sourced oils and interbedded shale-sourced oils as revealed by compound specific carbon isotopic analysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To date, questions remain as to how to differen tiate between coal- and interbedded shale-sourced oils in coal measures. Based on the hypothesis that δ13C value of sedimentary organic matter is controlled by the depositional environment and productivities of biota grown in such depositional setting, this note examines compound specific carbon isotopic profiles from coal and interbedded shale extracts using the gas chromatography-isotope ratio mass spectrometry technique (GC/IRMS). The results show that compound specific carbon isotope values from coal extracts are enriched in 13C relative to that of interbedded shale extracts, and provide useful information in characterizing coal- and interbedded shale-sourced oils in coal measures. An example for its successful application from the Turpan Basin, Northwestern China is presented.

  11. Biological marker characteristics of oils and asphalts from carbonate source rocks in a rapidly subsiding graben, Dead Sea, Israel

    Science.gov (United States)

    Rullkötter, Jürgen; Spiro, Baruch; Nissenbaum, Arie

    1985-06-01

    A detailed GC/MS study of biological marker compounds in the saturated and aromatic hydrocarbon fractions of oils and asphalts from the Dead Sea area, Israel, provided decisive information to the solution of a long-lasting controversy by showing that the asphalts are products of early generation in an immature stage from the same type of carbonate source rock which generated more mature oils. The asphalts are not biodegraded residues of the oils. Oils from six different wells, and asphalts from wells, outcrops, and a floating block from the Dead Sea all have very similar sterane and triterpane patterns. They all lack rearranged steranes (diasteranes) indicating a carbonate source matrix and compare reasonably well with a sample of Upper Cretaceous bituminous chalk from Nebi Musa. The main difference between the oils and the asphalts is a significantly higher triaromatic to mono- plus triaromatic steroid hydrocarbon ratio in the former. This is explained as a result of rapid subsidence and heating of their source rock close to the deep parts of the Dead Sea graben. The oils thus were generated in the more deeply buried source rock blocks under the graben fill, whereas the asphalts either originate from an immature source rock section closer to the graben rims or represent an earlier phase of generation and expulsion. This study also provides general information on the evolution of biological markers in carbonate source rocks. Low-activation-energy processes, like isomerisation of steranes, appear to occur much faster at low temperatures than in shales. The high sulfur content and less cross-linking of the biogenic organic matter into a complex kerogen structure are suggested to be responsible for this. Care should be taken when using only sterane isomerisation to assess the maturity of hydrocarbons from carbonate rocks and of carbonate-derived oils.

  12. Evaluating Biological Treatment Systems: (i) Moving Bed Biofilm Reactor versus Biological Aerated Filtration, and (ii) Sulfide-Induced corrosion in Anaerobic Digester Gas Piping

    OpenAIRE

    Asiedu, Kofi

    2001-01-01

    The research presented in this report is in two sections. Section I involved the performance of a moving bed biofilm reactor (MBBR) versus a biological aerated filtration (BAF) and Section II involved study on causes of deposition in anaerobic digester gas piping. The first section evaluated and compared the performance of a laboratory-scale MBBR and BAF for organic carbon and suspended solids removal. A kinetic study was also performed on the MBBR to evaluate the system performance. T...

  13. Enhanced nitrogen removal in a wastewater treatment process characterized by carbon source manipulation with biological adsorption and sludge hydrolysis.

    Science.gov (United States)

    Liu, Hongbo; Zhao, Fang; Mao, Boyang; Wen, Xianghua

    2012-06-01

    An innovative adsorption/nitrification/denitrification/sludge-hydrolysis wastewater treatment process (ENRS) characterized by carbon source manipulation with a biological adsorption unit and a sludge hydrolysis unit was developed to enhance nitrogen removal and reduce sludge production for municipal wastewater treatment. The system presented good performance in pollutants removal, yielding the effluent with average COD, NH(4)(+)-N, TN and TP of 48.5, 0.6, 13.2 and 1.0 mg/L, respectively. Sixty percent of the total carbon source in the influent was concentrated and separated by the quick adsorption of activated sludge, providing the possibilities of reusing waste carbon source in the denitrification tank and accumulating nitrobacteria in the nitrification tank. Low temperature of 6-15 °C and high hydraulic loading rate of 3.0-15.0 m(3)/d did not affect NH(4)(+)-N removal performance, yielding the NH(4)(+)-N of lower 1.0 mg/L in the effluent. Furthermore, 50% of the residual sludge in the ENRS system could be transformed into soluble COD (SCOD) by alkaline thermal hydrolysis with temperature of 60 °C and pH of 11, and the hydrolyzed carbon could completely substitute methanol as a good quality carbon to support high efficient denitrification.

  14. Analysis of oxygen sources and reaction pathways of carbon support corrosion at the cathode in PEMFC using oxygen-18 DEMS

    Energy Technology Data Exchange (ETDEWEB)

    Li Wei [Department of Chemical and Biological Engineering, University of Alabama, Box 870203, Tuscaloosa AL 35487-0203 (United States); Lane, Alan M., E-mail: alane@eng.ua.ed [Department of Chemical and Biological Engineering, University of Alabama, Box 870203, Tuscaloosa AL 35487-0203 (United States)

    2010-09-01

    Oxygen gas, water used to humidify the gases, and surface oxides originated from the carbon black and catalyst preparation are the three possible oxygen sources contributing to carbon support corrosion (CSC) at the cathode in proton exchange membrane fuel cells (PEMFC). To discriminate among them, oxygen was isotopically labeled by replacing regular water with oxygen-18 ({sup 18}O) enriched water (H{sub 2}{sup 18}O, 98%) in differential electrochemical mass spectrometry (DEMS). The DEMS spectra of the cathode exhaust gases O{sub 2}, O{sup 18}O, {sup 18}O{sub 2}, CO{sub 2}, CO{sup 18}O and C{sup 18}O{sub 2} (m/z equal to 32, 34, 36, 44, 46 and 48 correspondingly), sampled by a mass spectrometer during cyclic voltammetry (potential cycled for 100-1400 mV at the rate of 10 mV s{sup -1}) and chronoamperometry, were analyzed to identify the sources of oxygen, identify mechanistic pathways, and classify the surface oxides on carbon for CSC. It was found that water is the main direct oxygen source for CSC. Water reacts with carbon to produce at least three types of carbon surface oxides, which are then further oxidized with water to produce CO{sub 2} in different potential ranges.

  15. Characteristics of a high brightness gaseous field ion source employing tungsten-carbon doped NiAl needles

    Energy Technology Data Exchange (ETDEWEB)

    Mousa, Marwan S., E-mail: mmousa@mutah.edu.jo [Department of Physics, Mu' tah University, P.O. Box 7, Al-Karak (Jordan)

    2011-05-15

    We report on the characterization of a high brightness gaseous field ion source using an emitter made of a NiAl needle containing tiny spherical tungsten-carbon precipitates. By field evaporation of such a multiphase alloy, a surface protrusion is formed out of a precipitate, which can act as a small source size field ion emitter. The emission current-voltage characteristics of this emitter were recorded for a variety of parameters. The results obtained suggest that its application as a stable ion source is possible even on long term operation. -- Research highlights: {yields} High brightness gaseous field ion source of precipitation hardened NiAl+W+C emitter. {yields} Emission current-voltage characteristics are recorded for a variety of parameters. {yields} Very small virtual source sizes and energy spreads can be attained. {yields} Results suggest that application as long term stable ion source is possible.

  16. Quantifying sources, transport, deposition, and radiative forcing of black carbon over the Himalayas and Tibetan Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rudong; Wang, Hailong; Qian, Yun; Rasch, Philip J.; Easter, Richard C.; Ma, Po-Lun; Singh, Balwinder; Huang, Jianping; Fu, Qiang

    2015-01-01

    Black carbon (BC)particles over the Himalayas and Tibetan Plateau (HTP), both airborne and those deposited on snow, have been shown to affect snowmelt and glacier retreat. Since BC over the HTP may originate from a variety of geographical regions and emission sectors, it is essential to quantify the source-receptor relationships of BC in order to understand the contributions of natural and anthropogenic emissions and provide guidance for potential mitigation actions. In this study, we use the Community Atmosphere Model version 5 (CAM5) with a newly developed source tagging technique, nudged towards the MERRA meteorological reanalysis, to characterize the fate of BC particles emitted from various geographical regions and sectors. Evaluated against observations over the HTP and surrounding regions, the model simulation shows a good agreement in the seasonal variation of the near-surface airborne BC concentrations, providing confidence to use this modeling framework for characterizing BC source- receptor relationships. Our analysis shows that the relative contributions from different geographical regions and source sectors depend on seasons and the locations in the HTP. The largest contribution to annual mean BC burden and surface deposition in the entire HTP region is from biofuel and biomass (BB) emissions in South Asia, followed by fossil fuel (FF) emissions from South Asia, then FF from East Asia. The same roles hold for all the seasonal means except for the summer when East Asia FF becomes more important. For finer receptor regions of interest, South Asia BB and FF have the largest impact on BC in Himalayas and Central Tibetan Plateau, while East Asia FF and BB contribute the most to Northeast Plateau in all seasons and Southeast Plateau in the summer. Central Asia and Middle East FF emissions have relatively more important contributions to BC reaching Northwest Plateau, especially in the summer. Although the HTP local emissions only contribute about 10% of BC in

  17. Growth of Arthrobacter sp. strain JBH1 on nitroglycerin as the sole source of carbon and nitrogen.

    Science.gov (United States)

    Husserl, Johana; Spain, Jim C; Hughes, Joseph B

    2010-03-01

    Arthrobacter sp. strain JBH1 was isolated from nitroglycerin-contaminated soil by selective enrichment. Detection of transient intermediates and simultaneous adaptation studies with potential intermediates indicated that the degradation pathway involves the conversion of nitroglycerin to glycerol via 1,2-dinitroglycerin and 1-mononitroglycerin, with concomitant release of nitrite. Glycerol then serves as the source of carbon and energy.

  18. Influence of the carbon source on production of cellulases, hemicellulases and pectinases by Trichoderma reesei Rut C-30

    DEFF Research Database (Denmark)

    Olsson, Lisbeth; Christensen, T.M.I.E.; Hansen, K.P.;

    2003-01-01

    The growth and enzyme production by Trichoderma reesei Rut C-30 using different lignocellulosic materials as carbon source were investigated. Cellulose, sugar beet pulp and alkaline extracted sugar beet pulp (resulting in partial removal of hemicellulose, lignin and pectin) or mixtures thereof were...

  19. Metabolomics reveals differences of metal toxicity in cultures of Pseudomonas pseudoalcaligenes KF707 grown on different carbon sources

    Directory of Open Access Journals (Sweden)

    Sean Cameron Booth

    2015-08-01

    Full Text Available Co-contamination of metals and organic pollutants is a global problem as metals interfere with the metabolism of complex organics by bacteria. Based on a prior observation that metal tolerance was altered by the sole carbon source being used for growth, we sought to understand how metal toxicity specifically affects bacteria using an organic pollutant as their sole carbon source. To this end metabolomics was used to compare cultures of Pseudomonas pseudoalcaligenes KF707 grown on either biphenyl or succinate as the sole carbon source in the presence of either aluminum or copper. Using multivariate statistical analysis it was found that the metals caused perturbations to more cellular processes in the cultures grown on biphenyl than those grown on succinate. Aluminum induced many changes that were indicative of increased oxidative stress as metabolites involved in DNA damage and protection, the Krebs cycle and anti-oxidant production were altered. Copper also caused metabolic changes that were indicative of similar stress, as well as appearing to disrupt other key enzymes such as fumarase. Additionally, both metals caused the accumulation of biphenyl degradation intermediates indicating that they interfered with biphenyl metabolism. Together these results provide a basic understanding of how metal toxicity specifically affects bacteria at a biochemical level during the degradation of an organic pollutant and implicate the catabolism of this carbon source as a major factor that exacerbates metal toxicity.

  20. Metabolomics reveals differences of metal toxicity in cultures of Pseudomonas pseudoalcaligenes KF707 grown on different carbon sources.

    Science.gov (United States)

    Booth, Sean C; Weljie, Aalim M; Turner, Raymond J

    2015-01-01

    Co-contamination of metals and organic pollutants is a global problem as metals interfere with the metabolism of complex organics by bacteria. Based on a prior observation that metal tolerance was altered by the sole carbon source being used for growth, we sought to understand how metal toxicity specifically affects bacteria using an organic pollutant as their sole carbon source. To this end metabolomics was used to compare cultures of Pseudomonas pseudoalcaligenes KF707 grown on either biphenyl (Bp) or succinate (Sc) as the sole carbon source in the presence of either aluminum (Al) or copper (Cu). Using multivariate statistical analysis it was found that the metals caused perturbations to more cellular processes in the cultures grown on Bp than those grown on Sc. Al induced many changes that were indicative of increased oxidative stress as metabolites involved in DNA damage and protection, the Krebs cycle and anti-oxidant production were altered. Cu also caused metabolic changes that were indicative of similar stress, as well as appearing to disrupt other key enzymes such as fumarase. Additionally, both metals caused the accumulation of Bp degradation intermediates indicating that they interfered with Bp metabolism. Together these results provide a basic understanding of how metal toxicity specifically affects bacteria at a biochemical level during the degradation of an organic pollutant and implicate the catabolism of this carbon source as a major factor that exacerbates metal toxicity. PMID:26347721

  1. [Study on degradation of polycyclic aromatic hydrocarbons (PAHs) with different additional carbon sources in aged contaminated soil].

    Science.gov (United States)

    Yin, Chun-Qin; Jiang, Xin; Wang, Fang; Wang, Cong-Ying

    2012-02-01

    This study was conducted with different additional carbon sources (such as: glucose, DL-malic acid, citrate, urea and ammonium acetate) to elucidate the degradation of polycyclic aromatic hydrocarbons (PAHs) in aged contaminated soil under an indoor simulation experiment. The results showed that the quantity of CO2 emission in different additional carbon sources treatments was obviously much more than that of check treatment in the first week, and the quantity of CO2 emission in DL-malic acid treatment was the largest. The average CO2 production decreased in an order urea > glucose approximately citrate approximately DL-malic acid approximately ammonium acetate > check. Meanwhile, the amount of volatized PAHs in applied carbon sources treatments was significantly less than that in check treatment. The amount of three volatized PAHs decreased in an order phenanthrene > fluoranthene > benzo(b)fluoranthene. Compared with the check treatment, the average degradation rates of the three PAHs were significantly augmented in the supplied carbon sources treatments, in which rates of the three PAHs were much higher in DL-malic acid and urea treatments than those in other treatments. The largest proportion of residual was benzo(b)fluoranthene (from 72% to 81%) among three PAHs compounds, followed by fluoranthene (from 53% to 70% ) and phenanthrene (from 27% to 44%).

  2. Application of central composite design to optimize the amount of carbon source and prebiotics for Bifidobacterium bifidum BB01

    Directory of Open Access Journals (Sweden)

    Shu Guowei

    2016-06-01

    Full Text Available The objective of the present study was to obtain the optimum proportion of the carbon source and prebiotics for Bifidobacterium bifidum BB01 by the central composite design (CCD. The effect of carbon source (lactose and two prebiotics (inulin and fructooligosaccharides on the BB01 were observed by measuring the OD600 value, pH value and the viable counts at 18h. The final optimized concentrations of carbon source and prebiotics were: lactose 1.6%, inulin 0.26%, and fructooligosaccharides 0.22%. The result indicates that the growth of B. bifidum BB01 shows an significant increase in the optimized culture medium (p < 0.05, the OD600 value reached 1.434 at 18h, which increased 6.58% compared to the control. And the viable counts of B. bifidum BB01 increased 24.36% and reached (2.17±0.06 ×109cfu/mL. The results show that the optimization of the carbon source and prebiotics using CCD in this study is workable and necessary.

  3. A Multi-Walled Carbon Nanotube-based Biosensor for Monitoring Microcystin-LR in Sources of Drinking Water Supplies

    Science.gov (United States)

    A multi-walled carbon nanotube-based electrochemical biosensor is developed for monitoring microcystin-LR (MC-LR), a toxic cyanobacterial toxin, in sources of drinking water supplies. The biosensor electrodes are fabricated using dense, mm-long multi-walled CNT (MWCNT) arrays gro...

  4. Silurian and Devonian source rocks and crude oils from the western part of Libya: Organic geochemistry, palynology and carbon stratigraphy

    NARCIS (Netherlands)

    Elkelani, Mohamed M.A.

    2015-01-01

    The Early Silurian “hot” shales and Late Devonian black shales are major regional oil and gas source rocks in North Africa. Their deposition probably played a major role in global carbon cycling in general because of the large areas of the ocean affected. Comparing the Libyan δ13C record with record

  5. Carbon isotopic characteristics of hydrocarbon gases from coal-measure source rocks--A thermal simulation experiment

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jianjing; HU Huifang; SUN Guoqiang; JI Limin

    2006-01-01

    Gaseous hydrocarbon geochemistry research through a thermal simulation experiment in combination with the natural evolution process in which natural gases were formed from coal-measure source rocks revealed that the δ13C1 values of methane vary from light to heavy along with the increase of thermal evolution degree of coal-measure source rocks, and the δ13C2 values of ethane range from -28.3‰ to -20‰ (PDB). δ13C2 value was -28‰± ( Ro= 0.45% - 0.65%) at the lower thermal evolution stage of coal-measure source rocks. After the rocks entered the main hydrocarbon-generating stage (Ro=0.65% - 1.50%), δ13C2 values generally varied within the range of -26‰ - -23‰±; with further thermal evolution of the rocks the carbon isotopes of ethane became heavier and heavier, but generally less than - 20‰.The partial carbon isotope sequence inversion of hydrogen gases is a characteristic feature of mixing of natural gases of different origins. Under the condition of specially designated type of organic matter, hydrogen source rocks may show this phenomenon via their own evolution.In the lower evolution stages of the rocks, it is mainly determined by organic precursors that gaseous hydrocarbons display partial inversion of the carbon isotope sequence and the carbon isotopic values of ethane are relatively low. These characteristic features also are related to the geochemical composition of primary soluble organic matter.

  6. Oxygen vectors used for S-adenosylmethionine production in recombinant Pichia pastoris with sorbitol as supplemental carbon source.

    Science.gov (United States)

    Zhang, Jian-Guo; Wang, Xue-Dong; Zhang, Ji-Ning; Wei, Dong-Zhi

    2008-04-01

    In order to increase the yield of S-adenosylmethionine (SAM) in recombinant Pichia pastoris, a strategy of adding oxygen vectors and supplemental carbon sources was described. Three organic solutions were used as oxygen vectors for SAM accumulation at different concentrations and addition times. Firstly, n-hexane (0.5%) or n-heptane (1.0%) was added after 72 h of cultivation to improve SAM production. Carbon metabolism was scarce during the induction phase because of low methanol concentration. Secondly, sorbitol (1.2%), selected from three candidates (glycerol, lactic acid, and sorbitol), was used as the supplemental carbon source. The yield of SAM was improved significantly (53.26%) at 1.0%n-heptane added at 72 h (48 h induction), 1.2% sorbitol added at 72, 96, and 120 h of cultivation and 1.0% methanol added every 24 h during cultivation.

  7. Violent breaking wave impacts. Part 3. Effects of scale and aeration

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Bullock, G. N.; Hogg, A. J.

    2015-01-01

    The effects of scale and aeration on violent breaking wave impacts with trapped and entrained air are investigated both analytically and numerically. By dimensional analysis we show that the impact pressures for Froude scaled conditions prior to the impact depend on the scale and aeration level....... The Bagnold-Mitsuyasu scaling law for the compression of an air pocket by a piston of incompressible water is rederived and generalised to 3D air pockets of arbitrary shape. Numerical results for wall pressure, force and impulse are then presented for a flip-through impact, a low-aeration impact and a high-aeration...... impact, for nine scales and five levels of initial aeration. Two of these impact types trap a pocket of air at the wall. Among the findings of the paper is that for fixed initial aeration, impact pressures from the flip-through impact broadly follow Froude scaling. This is also the case for the two...

  8. Nonequilibrium Thermodynamic Model of Manganese Carbonate Oxidation

    Institute of Scientific and Technical Information of China (English)

    郝瑞霞; 彭省临

    1999-01-01

    Manganese carbonate can be converted to many kinds of manganese oxides when it is aerated in air and oxygen.Pure manganese carbonate can be changed into Mn3O4 and γ-MnOOH,and manganese carbonate ore can be converted to MnO2 under the air-aerating and oxygen-aerating circumstances.The oxidation process of manganese carbonate is a changing process of mineral association,and is also a converting process of valence of manganese itself.Not only equilibrium stat,but also nonequilibrium state are involved in this whole process,This process is an irreversible heterogeneous complex reaction,and oberys the nonequilibrium thermodynamic model,The oxidation rate of manganese cabonate is controlled by many factors,especially nonmanganese metallic ions which play an important role in the oxidation process of manganese carbonate.

  9. Fabrication and Properties of SiB6-B4C with Phenolic Resin as a Carbon Source

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Si-B-C ceramic composites were synthesized using SiB6, B4C, and phenolic resin as a carbon source by pressureless sintering in an Ar atmosphere. Then, the Si-B-C ceramic composites were fabricated to determine their potential for applications as high hardness and high temperature composites. The X-ray diffraction patterns of sintered bodies of SiB6-B4C with carbonized phenolic resin can be seen that SiB6 and C changed to B4C and SiC. In this study, it is obtained that carbonized phenolic resin is good addition material as a reaction material comparing to carbon powder at 1683 K for 1 h by pressureless sintering in an Ar atmosphere.

  10. A TEM study of soot, carbon nanotubes, and related fullerene nanopolyhedra in common fuel-gas combustion sources

    International Nuclear Information System (INIS)

    Nanoparticle aggregates collected by thermophoretic precipitation from natural gas-air and propane-air kitchen stove top flame exhausts, natural gas-air water heater roof-top exhausts, and other common fuel-gas combustion sources were observed by transmission electron microscopy to consist of occasional aggregates of mostly turbostratic carbon spherules, aggregates of crystalline graphite nanoparticles mixed with other fullerene nanoforms; and aggregates of various sizes of multiwall carbon nanotubes and other multishell, fullerene polyhedra for optimal blue-flame combustion. The carbon nanotube structures and end cap variations as well as fullerene polyhedral structures were observed to be the same as those for arc-evaporation produced nanoaggregates. Nanoparticle aggregation or the occurrence of carbon nanoforms always occurred as aggregates with nominal sizes ranging from about 0.5 μm to 1.5 μm

  11. Growth of Hexagonal Columnar Nanograin Structured SiC Thin Films on Silicon Substrates with Graphene–Graphitic Carbon Nanoflakes Templates from Solid Carbon Sources

    Directory of Open Access Journals (Sweden)

    Wanshun Zhao

    2013-04-01

    Full Text Available We report a new method for growing hexagonal columnar nanograin structured silicon carbide (SiC thin films on silicon substrates by using graphene–graphitic carbon nanoflakes (GGNs templates from solid carbon sources. The growth was carried out in a conventional low pressure chemical vapor deposition system (LPCVD. The GGNs are small plates with lateral sizes of around 100 nm and overlap each other, and are made up of nanosized multilayer graphene and graphitic carbon matrix (GCM. Long and straight SiC nanograins with hexagonal shapes, and with lateral sizes of around 200–400 nm are synthesized on the GGNs, which form compact SiC thin films.

  12. 13C-metabolic flux ratio and novel carbon path analyses confirmed that Trichoderma reesei uses primarily the respirative pathway also on the preferred carbon source glucose

    Directory of Open Access Journals (Sweden)

    Saloheimo Markku

    2009-10-01

    Full Text Available Abstract Background The filamentous fungus Trichoderma reesei is an important host organism for industrial enzyme production. It is adapted to nutrient poor environments where it is capable of producing large amounts of hydrolytic enzymes. In its natural environment T. reesei is expected to benefit from high energy yield from utilization of respirative metabolic pathway. However, T. reesei lacks metabolic pathway reconstructions and the utilization of the respirative pathway has not been investigated on the level of in vivo fluxes. Results The biosynthetic pathways of amino acids in T. reesei supported by genome-level evidence were reconstructed with computational carbon path analysis. The pathway reconstructions were a prerequisite for analysis of in vivo fluxes. The distribution of in vivo fluxes in both wild type strain and cre1, a key regulator of carbon catabolite repression, deletion strain were quantitatively studied by performing 13C-labeling on both repressive carbon source glucose and non-repressive carbon source sorbitol. In addition, the 13C-labeling on sorbitol was performed both in the presence and absence of sophorose that induces the expression of cellulase genes. Carbon path analyses and the 13C-labeling patterns of proteinogenic amino acids indicated high similarity between biosynthetic pathways of amino acids in T. reesei and yeast Saccharomyces cerevisiae. In contrast to S. cerevisiae, however, mitochondrial rather than cytosolic biosynthesis of Asp was observed under all studied conditions. The relative anaplerotic flux to the TCA cycle was low and thus characteristic to respiratory metabolism in both strains and independent of the carbon source. Only minor differences were observed in the flux distributions of the wild type and cre1 deletion strain. Furthermore, the induction of the hydrolytic gene expression did not show altered flux distributions and did not affect the relative amino acid requirements or relative anabolic

  13. Characteristics of a high brightness gaseous field ion source employing tungsten-carbon doped NiAl needles.

    Science.gov (United States)

    Mousa, Marwan S

    2011-05-01

    We report on the characterization of a high brightness gaseous field ion source using an emitter made of a NiAl needle containing tiny spherical tungsten-carbon precipitates. By field evaporation of such a multiphase alloy, a surface protrusion is formed out of a precipitate, which can act as a small source size field ion emitter. The emission current-voltage characteristics of this emitter were recorded for a variety of parameters. The results obtained suggest that its application as a stable ion source is possible even on long term operation. PMID:21296502

  14. Effects of aeration position on organics, nitrogen and phosphorus removal in combined oxidation pond-constructed wetland systems.

    Science.gov (United States)

    Wang, Xiaoou; Tian, Yimei; Zhao, Xinhua; Peng, Sen; Wu, Qing; Yan, Lijian

    2015-12-01

    Given that few studies investigated the effects of aeration position (AP) on the performance of aerated constructed wetlands, the aim of this study was to evaluate the effects of AP on organics, nitrogen and phosphorus removal in lab-scale combined oxidation pond-constructed wetland (OP-CW) systems. Results showed that middle aeration allowed the CW to possess more uniform oxygen distribution and to achieve greater removals of COD and NH3-N, while the CW under bottom aeration and surface aeration demonstrated more distinct stratification of oxygen distribution and surface aeration brought about better TN removal capacity for the OP-CW system. However, no significant influence of artificial aeration or AP on TP removal was observed. Overall, AP could significantly affect the spatial distribution of dissolved oxygen by influencing the oxygen diffusion paths in aerated CWs, thereby influencing the removal of pollutants, especially organics and nitrogen, which offers a reference for the design of aerated CWs.

  15. [Carbon source metabolic diversity of soil microbial community under different climate types in the area affected by Wenchuan earthquake].

    Science.gov (United States)

    Zhang, Guang-Shuai; Lin, Yong-Ming; Ma, Rui-Feng; Deng, Hao-Jun; Du, Kun; Wu, Cheng-Zhen; Hong, Wei

    2015-02-01

    The MS8.0 Wenchuan earthquake in 2008 led to huge damage to land covers in northwest Sichuan, one of the critical fragile eco-regions in China which can be divided into Semi-arid dry hot climate zone (SDHC) and Subtropical humid monsoon climate zone (SHMC). Using the method of Bilog-ECO-microplate technique, this paper aimed to determine the functional diversity of soil microbial community in the earthquake-affected areas which can be divided into undamaged area (U), recover area (R) and damaged area without recovery (D) under different climate types, in order to provide scientific basis for ecological recovery. The results indicated that the average-well-color-development (AWCD) in undamaged area and recovery area showed SDHC > SHMC, which was contrary to the AWCD in the damaged area without recovery. The AWCD of damaged area without recovery was the lowest in both climate zones. The number of carbon source utilization types of soil microbial in SHMC zone was significantly higher than that in SDHC zone. The carbon source utilization types in both climate zones presented a trend of recover area > undamaged area > damaged area without recovery. The carbon source metabolic diversity characteristic of soil microbial community was significantly different in different climate zones. The diversity index and evenness index both showed a ranking of undamaged area > recover area > damaged area without recovery. In addition, the recovery area had the highest richness index. The soil microbial carbon sources metabolism characteristic was affected by soil nutrient, aboveground vegetation biomass and vegetation coverage to some extent. In conclusion, earthquake and its secondary disasters influenced the carbon source metabolic diversity characteristic of soil microbial community mainly through the change of aboveground vegetation and soil environmental factors. PMID:26031097

  16. Experience of drilling wells using pump-compressor unit to inject aerated fluid

    Energy Technology Data Exchange (ETDEWEB)

    Oleynik, S.P.; Beley, I.V.; Lopatin, Yu.S.; Pytel, S.P.; Vasilak, I.I.; Yushkevich, V.I.

    1979-01-01

    Results are described from drilling wells with flushing by highly aerated clay fluid with the help of a UNGA unit which includes pumps and compressors of the drilling unit UBSh-1 which permits injection of an aerated mixture under pressures considerably exceeding the pressure of its formation. Qualitative and technical-economic advantages of drilling with flushing by aerated solutions with the use of a unit for injecting gas-liquid agents are presented.

  17. Aeration-Induced Changes in Temperature and Nitrogen Dynamics in a Dimictic Lake.

    Science.gov (United States)

    Holmroos, Heidi; Horppila, Jukka; Laakso, Sanna; Niemistö, Juha; Hietanen, Susanna

    2016-07-01

    Low levels of oxygen (O) in the hypolimnion layer of lakes are harmful to benthic animals and fish; they may also adversely affect nutrient cycles. Artificial aeration is often used in lake management to counteract these problems, but the effects of aeration on nitrogen (N) cycling are not known. We studied the effects of hypolimnetic aeration on N dynamics and temperature in a eutrophic lake by comparing continuous and pulsed aeration with a nonaerated station. Aeration decreased the accumulation of NH-N deep in the lake (20-33 m) by supplying O for nitrification, which in turn provided substrate for denitrification and promoted N removal. Aeration also increased the temperature in the hypolimnion. Denitrification rate was highest in the nonaerated deep areas (average, 7.62 mg N m d) due to very high rates during spring turnover of the water column, demonstrating that natural turnover provides O for nitrification. During stratification, denitrification was highest at the continuously aerated station (4.06 mg N m d) and lowest at the nonaerated station (3.02 mg N m d). At the periodically aerated station, aeration pauses did not restrict the increase in temperature but resulted in accumulation of NH-N and decreased the contribution of denitrification as a nitrate reduction process. Our findings demonstrate that hypolimnetic aeration can substantially affect N cycling in lakes and that the effect depends on the aeration strategy. Because N is one of the main nutrients controlling eutrophication, the effects of aeration methods on N removal should be considered as part of strategies to manage water quality in lakes.

  18. Aeration-Induced Changes in Temperature and Nitrogen Dynamics in a Dimictic Lake.

    Science.gov (United States)

    Holmroos, Heidi; Horppila, Jukka; Laakso, Sanna; Niemistö, Juha; Hietanen, Susanna

    2016-07-01

    Low levels of oxygen (O) in the hypolimnion layer of lakes are harmful to benthic animals and fish; they may also adversely affect nutrient cycles. Artificial aeration is often used in lake management to counteract these problems, but the effects of aeration on nitrogen (N) cycling are not known. We studied the effects of hypolimnetic aeration on N dynamics and temperature in a eutrophic lake by comparing continuous and pulsed aeration with a nonaerated station. Aeration decreased the accumulation of NH-N deep in the lake (20-33 m) by supplying O for nitrification, which in turn provided substrate for denitrification and promoted N removal. Aeration also increased the temperature in the hypolimnion. Denitrification rate was highest in the nonaerated deep areas (average, 7.62 mg N m d) due to very high rates during spring turnover of the water column, demonstrating that natural turnover provides O for nitrification. During stratification, denitrification was highest at the continuously aerated station (4.06 mg N m d) and lowest at the nonaerated station (3.02 mg N m d). At the periodically aerated station, aeration pauses did not restrict the increase in temperature but resulted in accumulation of NH-N and decreased the contribution of denitrification as a nitrate reduction process. Our findings demonstrate that hypolimnetic aeration can substantially affect N cycling in lakes and that the effect depends on the aeration strategy. Because N is one of the main nutrients controlling eutrophication, the effects of aeration methods on N removal should be considered as part of strategies to manage water quality in lakes. PMID:27380085

  19. Performance Evaluation of an Oxidation Ditch System with a Disc Aerator

    OpenAIRE

    Abdel E. Ghaly; Ashley Thistle

    2011-01-01

    Problem statement: The oxidation ditch system has been used to treat various types of wastewaters. Several types of aerators are used to supply the treatment process with oxygen. Among these devices, the disc aerator has certain advantages regarding foam generation over the brush and paddle type rotors, but the main disadvantages of this aerator is the limited oxygenation capacity. The main objectives of this study were to study the effects of various design parameters and system operation pa...

  20. Chemical kinetics study of hydrocarbon regeneration from organic matter in carbonate source rocks and its significance

    Institute of Scientific and Technical Information of China (English)

    LU ShuangFang; ZHONG NingNing; XUE HaiTao; PAN ChangChun; LI JiJun; LI HongTao

    2007-01-01

    In the comparison research of hydrocarbon regeneration, a low maturity carbonate source rock is heated to different temperatures in a gold tube to obtain a series of samples with different maturities. Then, the heated samples, before and after extraction, are subjected to Rock-Eval pyrolysis through a thermal simulation of hydrocarbon regeneration in order to inspect pyrolysis characteristics and probe into the characteristics of the chemical kinetics of each sample. The results indicate that, whether hydrocarbon regeneration peak is delayed or advanced, the potential of hydrocarbon regeneration is closely related to the expulsion amount and breakdown maturity of primary hydrocarbon generation. After extraction, the average activation energy of artificially maturated samples increases with the in creasing maturity, but the chemical kinetic properties of un-extracted samples decrease. The calibrated chemical kinetic models that describe extracted and un-extracted samples are applied to the Bohai Bay and the Songliao Basin, and the results indicate that the combination of the two models can explain some contradictory conclusions previously reported. These results also facilitate the quantitative evaluation of the amount of hydrocarbon regeneration by the chemical kinetic method.