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Sample records for fixed-bed anaerobic sequencing

  1. A new device to select carriers for biomass immobilization and application in an aerobic/anaerobic fixed-bed sequencing batch biofilm reactor for nitrogen removal.

    PubMed

    Sarti, A; Lamon, A W; Ono, A; Foresti, E

    2016-12-01

    This study proposes a new approach to selecting a biofilm carrier for immobilization using dissolved oxygen (DO) microsensors to measure the thickness of aerobic and anaerobic layers in biofilm. The biofilm carriers tested were polyurethane foam, mineral coal (MC), basaltic gravel, and low-density polyethylene. Development of layers in the biofilm carrier surface was evaluated using a flow cell device, and DO profiles were conducted to determine the size of the layers (aerobic and anaerobic). MC was the biofilm carrier selected due to allowing the development of larger aerobic and anaerobic layers in the biofilm (896 and 1,058 μm, respectively). This ability is supposed to improve simultaneous nitrogen removal by nitrification and denitrification biological processes. Thus, as a biofilm carrier, MC was used in a fixed-bed sequencing batch biofilm reactor (FB-SBBR) for treatment of wastewater with a high ammonia concentration (100-400 mgNH4(+)-N L(-1)). The FB-SBBR (15.0 L) was filled with matrices of the carrier and operated under alternating aeration and non-aeration periods of 6 h each. At a mean nitrogen loading rate of 0.55 ± 0.10 kgNH4(+)-N m(-3) d(-1), the reactor attained a mean nitrification efficiency of 95 ± 9% with nitrite as the main product (aerobic period). Mean denitrification efficiency during the anoxic period was 72 ± 13%.

  2. Anaerobic treatment of winery wastewater in fixed bed reactors.

    PubMed

    Ganesh, Rangaraj; Rajinikanth, Rajagopal; Thanikal, Joseph V; Ramanujam, Ramamoorty Alwar; Torrijos, Michel

    2010-06-01

    The treatment of winery wastewater in three upflow anaerobic fixed-bed reactors (S9, S30 and S40) with low density floating supports of varying size and specific surface area was investigated. A maximum OLR of 42 g/l day with 80 +/- 0.5% removal efficiency was attained in S9, which had supports with the highest specific surface area. It was found that the efficiency of the reactors increased with decrease in size and increase in specific surface area of the support media. Total biomass accumulation in the reactors was also found to vary as a function of specific surface area and size of the support medium. The Stover-Kincannon kinetic model predicted satisfactorily the performance of the reactors. The maximum removal rate constant (U(max)) was 161.3, 99.0 and 77.5 g/l day and the saturation value constant (K(B)) was 162.0, 99.5 and 78.0 g/l day for S9, S30 and S40, respectively. Due to their higher biomass retention potential, the supports used in this study offer great promise as media in anaerobic fixed bed reactors. Anaerobic fixed-bed reactors with these supports can be applied as high-rate systems for the treatment of large volumes of wastewaters typically containing readily biodegradable organics, such as the winery wastewater.

  3. Kinetics of thermophilic anaerobes in fixed-bed reactors.

    PubMed

    Perez, M; Romero, L I; Sales, D

    2001-08-01

    The main objective of this study is to estimate growth kinetic constants and the concentration of "active" attached biomass in two anaerobic thermophilic reactors which contain different initial sizes of immobilized anaerobic mixed cultures and decompose distillery wastewater. This paper studies the substrate decomposition in two lab-scale fixed-bed reactors operating at batch conditions with corrugated tubes as support media. It can be demonstrated that high micro-organisms-substrate ratios favor the degradation activity of the different anaerobic cultures, allowing the stable operation without lag-phases and giving better quality in effluent. The kinetic parameters obtained--maximum specific growth rates (mu(max)), non-biodegradable substrate (S(NB)) and "active or viable biomass" concentrations (X(V0))--were obtained by applying the Romero kinetic model [L.I. Romero, 1991. Desarrollo de un modelo matemático general para los procesos fermentativos, Cinética de la degradación anaerobia, Ph.D. Thesis, University of Cádiz (Spain), Serv. Pub. Univ. Cádiz], with COD as substrate and methane (CH4) as the main product of the anaerobic process. This method is suitable to calculate and to differentiate the main kinetic parameters of both the total anaerobic mixed culture and the methanogenic population. Comparison of experimental measured concentration of volatile attached solids (VS(att)) in both reactors with the estimated "active" biomass concentrations obtained by applying Romero kinetic model [L.I. Romero, 1991. Desarrollo de un modelo matemático general para los procesos fermentativos, Cinética de la degradación anaerobia, Ph.D. Thesis, University of Cádiz (Spain), Serv. Pub. Univ. Cádiz] shows that a large amount of inert matter is present in the fixed-bed reactor.

  4. Evaluation of integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor for decolorization and biodegradation of azo dye acid red 18: comparison of using two types of packing media.

    PubMed

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    Two integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor (FB-SBBR) were operated to evaluate decolorization and biodegradation of azo dye Acid Red 18 (AR18). Volcanic pumice stones and a type of plastic media made of polyethylene were used as packing media in FB-SBBR1 and FB-SBBR2, respectively. Decolorization of AR18 in both reactors followed first-order kinetic with respect to dye concentration. More than 63.7% and 71.3% of anaerobically formed 1-naphthylamine-4-sulfonate (1N-4S), as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase in FB-SBBR1 and FB-SBBR2, respectively. Based on statistical analysis, performance of FB-SBBR2 in terms of COD removal as well as biodegradation of 1N-4S was significantly higher than that of FB-SBBR1. Spherical and rod shaped bacteria were the dominant species of bacteria in the biofilm grown on the pumice stones surfaces, while, the biofilm grown on surfaces of the polyethylene media had a fluffy structure.

  5. Modeling for Anaerobic Fixed-Bed Biofilm Reactors

    SciTech Connect

    Liu, B. Y. M.; Pfeffer, J. T.

    1989-06-01

    The specific objectives of this research were: 1. to develop an equilibrium model for chemical aspects of anaerobic reactors; 2. to modify the equilibrium model for non-equilibrium conditions; 3. to incorporate the existing biofilm models into the models above to study the biological and chemical behavior of the fixed-film anaerobic reactors; 4. to experimentally verify the validity of these models; 5. to investigate the biomass-holding ability of difference packing materials for establishing reactor design criteria.

  6. Electrical conductivity as a state indicator for the start-up period of anaerobic fixed-bed reactors.

    PubMed

    Robles, A; Latrille, E; Ribes, J; Bernet, N; Steyer, J P

    2016-01-01

    The aim of this work was to analyse the applicability of electrical conductivity sensors for on-line monitoring the start-up period of an anaerobic fixed-bed reactor. The evolution of bicarbonate concentration and methane production rate was analysed. Strong linear relationships between electrical conductivity and both bicarbonate concentration and methane production rate were observed. On-line estimations of the studied parameters were carried out in a new start-up period by applying simple linear regression models, which resulted in a good concordance between both observed and predicted values. Electrical conductivity sensors were therefore identified as an interesting method for monitoring the start-up period of anaerobic fixed-bed reactors due to its reliability, robustness, easy operation, low cost, and minimum maintenance compared with the currently used sensors.

  7. Advanced regeneration and fixed-bed study of ammonium and potassium removal from anaerobic digested wastewater by natural zeolite.

    PubMed

    Guo, Xuejun; Zeng, Larry; Jin, Xin

    2013-05-01

    Highly efficient regeneration of natural zeolite was developed in conjunction with the removal of high concentrations of ammonia and potassium from the reverse osmosis effluent of anaerobic-digested wastewater by fixed-bed ion exchange. The elution and uptake behavior of ammonium and potassium in the fixed bed were studied. Both batch desorption tests and on-column regeneration were conducted to develop an optimum regeneration condition compatible with the wastewater requirements. The effectiveness of ammonium elution increased with increasing alkaline concentration. The increase of salt dose significantly enhanced the ammonium maximum in the elution solution. Complete ammonium elution was achieved in 6 bed volumes (BV) when the alkaline and salt concentrations were respectively 0.1 mol/L and 18.6 g/L at a flow rate of 2.5-3.0 BV/hr. Due to the higher affinity of potassium with natural clinoptilolite, complete potassium elution was not achieved in all cases.

  8. Temperature effect towards methane gas production and performances of anaerobic fixed bed reactors

    NASA Astrophysics Data System (ADS)

    Budiastuti, H.; Widyabudiningsih, D.; Kurnia, D. R. D.

    2016-11-01

    This study was conducted to observe the effect of temperature towards methane gas production and performances of Anaerobic Fixed Bed Reactors (AFBR) in degrading artificial wastewater. During seeding and acclimatization as well as operation at normal loading rates the reactor was controlled at 35 ± 1 °C. The reactor temperature was then switched to room temperature to compare its performance with performance of the temperature controlled reactor. Seeding was performed by wastewater feeding at concentration of 5,300 mgCOD/L. Seeding was continued to acclimatization after COD efficiency reached about 30% and mixed liquor volatile suspended solids (MLVSS) in the reactor were in the range of 28 to 29 g/L. Acclimatization was conducted by step increased feeding while obtaining organic loading rates (OLR) of 530 mgCOD/L/day and 40 days HRT, and it was stopped when COD efficiencies almost constant at about 80% were achieved. Normal loads at OLR of 530 mgCOD/L/day and HRT of 40 days resulted in COD efficiencies in the range of 80 to 92%, produced methane gas ranged from 80 to 170 ml/day, at pH around 7 during controlled temperature. At room temperature, COD efficiencies decreased to the fluctuated range of 78 to 84%, methane gas dropped to the highest of 144 ml/day but pH range was still at around 7. At OLR 1.5 times normal OLR (795 mgCOD/L/day) and HRT of 40 days, the controlled temperature reactor shows superiority by producing efficiencies in the range of 84 to 94% and 260 mL/day of CH4 as the highest gas produced during observation. Efficiencies of COD obtained during uncontrolled temperature dropped to the range of 60 to 80%. The uncontrolled temperature reactor only produced the highest CH4 production of 48 mL/day. pH from both reactors still ranged in the normal pH range about 7. It shows that AFBR has to be controlled at around 35 °C to produce higher COD efficiencies and methane gas production.

  9. Evaluation of ammonium adsorption in biochar-fixed beds for treatment of anaerobically digested swine slurry: Experimental optimization and modeling.

    PubMed

    Kizito, Simon; Wu, Shubiao; Wandera, Simon Mdondo; Guo, Luchen; Dong, Renjie

    2016-09-01

    Fixed-bed column experiments were performed to investigate the effect of influent concentration, flow rate, and adsorbent bed depth on ammonium adsorption from anaerobically digested swine slurry using three types of biochar made from corncobs (MCB), hardwood (WB), and mixed sawdust pellets (MSB). WB performed better than the other two biochar types with a maximum sorption capacity of 67-114mg/g due to its superior surface area and larger pore volume. Ammonium adsorption kinetics and dynamics depended on the influent NH4(+)-N concentration, applied inflow flow rate, and the depth of the fixed bed. Maximum sorption capacities under influent NH4(+)-N concentration of 500mg/L, were identified to be 114.2mg/g, 108.9mg/g, and 24.7mg/g at inflow rate of 15mL/min for WB, MCB, and MSB, respectively. The data shows that using deeper beds and applying lower flow rates could be a better strategy to increase ammonium adsorption in biochar-fixed beds. Moreover, three kinetic models (Thomas, Adams-Bohart (BDST), and Yoon-Nelson) were applied to the experimental data to predict breakthrough curves and determine characteristic adsorption parameters for process design. The applied models fitted data in the order: Thomas (R(2)=0.971)>BDST (R(2)=0.960)>Yoon-Nelson (R(2)=0.940). It was concluded that ammonium adsorption in biochar-fixed beds could be an effective method for routine cyclic treatment of slurry. However, further effluent polishing is required to meet discharge requirements.

  10. Light and electron microscopic examinations of methane-producing biofilms from anaerobic fixed-bed reactors. [Methanothrix spp. ; Methanosarcina spp

    SciTech Connect

    Robinson, R.W.; Akin, D.E.; Nordstedt, R.A.; Thomas, M.V.; Aldrich, H.C.

    1984-07-01

    Ultrastructural examinations were performed on biofilms from eight anaerobic fixed-bed reactors filled with various packing materials and operated on fresh swine waste. By using light, UV, scanning, and transmission electron microscopy, the distribution of a diverse microbial population composed of bacteria and a few yeasts was determined. This is the first time that the ultrastructure of in situ anaerobic digestor biofilms has been reported. A large number of methanogenic bacteria were identified by their fluorescence under 420 nm of radiation. Of these, two morphologically distinct types were most prevalent in the films. Methanothrix spp. was present in high numbers at the film surface, whereas Methanosarcina spp. were commonly embedded in the lower regions of the of the film. Inhabitants of the film were surrounded by an exopolysaccharide matrix that was very dense toward the base. An extensive network of channels was observed throughout the matrix that may facilitate gas and nutrient exchange to the lower regions of the film.

  11. Strategy of mitigating ammonium-rich waste inhibition on anaerobic digestion by using illuminated bio-zeolite fixed-bed process.

    PubMed

    Zhang, Nan; Stanislaus, Mishma Silvia; Hu, Xiaohong; Zhao, Chenyu; Zhu, Qi; Li, Dawei; Yang, Yingnan

    2016-12-01

    Intermittent illumination combined with bio-zeolite fixed-bed process was utilized to improve the efficiency of anaerobic digestion with ammonium-rich substrate. The batch experiments were carried out at NH4(+)-N concentration of 2211mg/L under intermittent illumination and dark (as control) conditions, respectively. The illuminated bioreactor achieved higher methane production (287mL/g-DOC) and ATP value (0.38μmol/L) than that under dark condition. Then the bio-zeolite fixed-bed bioreactor (NH4(+)-N concentration: 3000mg/L) was used to study the additional efficiency on the illuminated ammonium-rich anaerobic digestion process. The result showed that the illuminated fixed-bed bioreactor presented the greatest methane concentration (70%), methane yield (283mL/g-DOC) and quantity of methanogens comparing with no-bed bioreactor. Furthermore, the illuminated fixed-bed bioreactor achieved better performance during 118-day semi-continuous fermentation. The combination of the intermittent illumination and bio-zeolite fixed-bed strategy contributed to the higher efficiency and stability of the ammonium-rich anaerobic digestion process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Treatment of ammonium-rich swine waste in modified porphyritic andesite fixed-bed anaerobic bioreactor.

    PubMed

    Wang, Qinghong; Yang, Yingnan; Li, Dawei; Feng, Chuanping; Zhang, Zhenya

    2012-05-01

    In this study, a modified porphyritic andesite (WRS) was developed as ammonium adsorbent and bed material for the anaerobic digestion of ammonium-rich swine waste. The performance in bioreactors with modified WRS, natural WRS, calcium chloride and no additives was investigated. The bioreactor with modified WRS exhibited the best performance, with start-up time on the 7th day, methane yield of 359.71 ml/g-VS, and COD removal of 67.99% during all 44 days of the experiment at 35°C. The effective ammonium adsorption and essential ions dissociation for microorganisms by modified WRS, as well as the immobilization of microbial on the surface of the modified WRS play a great role on the high efficiency anaerobic digestion of ammonium-rich swine waste.

  13. Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater.

    PubMed

    Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

    2017-02-20

    Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal.

  14. Production of biohythane from food waste via an integrated system of continuously stirred tank and anaerobic fixed bed reactors.

    PubMed

    Yeshanew, Martha M; Frunzo, Luigi; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni

    2016-11-01

    The continuous production of biohythane (mixture of biohydrogen and methane) from food waste using an integrated system of a continuously stirred tank reactor (CSTR) and anaerobic fixed bed reactor (AFBR) was carried out in this study. The system performance was evaluated for an operation period of 200days, by stepwise shortening the hydraulic retention time (HRT). An increasing trend of biohydrogen in the CSTR and methane production rate in the AFBR was observed regardless of the HRT shortening. The highest biohydrogen yield in the CSTR and methane yield in the AFBR were 115.2 (±5.3)L H2/kgVSadded and 334.7 (±18.6)L CH4/kgCODadded, respectively. The AFBR presented a stable operation and excellent performance, indicated by the increased methane production rate at each shortened HRT. Besides, recirculation of the AFBR effluent to the CSTR was effective in providing alkalinity, maintaining the pH in optimal ranges (5.0-5.3) for the hydrogen producing bacteria.

  15. Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater

    PubMed Central

    Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

    2017-01-01

    Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal. PMID:28216654

  16. Kinetics of anaerobic degradation of screened dairy manure by upflow fixed bed digesters: effect of natural zeolite addition.

    PubMed

    Nikolaeva, S; Sánchez, E; Borja, R; Raposo, F; Colmenarejo, M F; Montalvo, S; Jiménez-Rodríguez, A M

    2009-02-01

    The effect of the hydraulic retention time (HRT) on the performance of two up-flow anaerobic fixed bed digesters (UFAFBDs) packed with waste tire rubber (D1) and waste tire rubber and zeolite (D2) as micro-organism immobilization supports was studied. It was found that a first-order kinetic model described well the experimental results obtained. The kinetic constants for COD, BOD5, total solids (TS) and volatile solids (VS) removal were determined to be higher in digester D2 than in digester D1 or control. Specifically, they were 0.28 +/- 0.01, 0.32 +/- 0.02, 0.16 +/- 0.01 and 0.24 +/- 0.01 d(- 1) respectively for D1 and 0.33 +/- 0.02, 0.40 +/- 0.02, 0.21 +/- 0.01 and 0.28 +/- 0.01 d(- 1) respectively for D2. This was significant at the 95% confidence level. In addition, the first-order model was also adequate for assessing the effect of the HRT on the removal efficiency and methane production. Maximum methane yield and the first-order constant for methane production were determined and the results obtained were comparable with those obtained by other authors but operating at higher HRTs. Maximum methane yields and the kinetic constant for methane production were 11.1% and 29.4% higher in digester D2 than in D1.

  17. Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater

    NASA Astrophysics Data System (ADS)

    Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

    2017-02-01

    Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal.

  18. Media arrangement impacts cell growth in anaerobic fixed-bed reactors treating sugarcane vinasse: Structured vs. randomic biomass immobilization.

    PubMed

    de Aquino, Samuel; Fuess, Lucas Tadeu; Pires, Eduardo Cleto

    2017-03-23

    This study reports on the application of an innovative structured-bed reactor (FVR) as an alternative to conventional packed-bed reactors (PBRs) to treat high-strength solid-rich wastewaters. Using the FVR prevents solids from accumulating within the fixed-bed, while maintaining the advantages of the biomass immobilization. The long-term operation (330days) of a FVR and a PBR applied to sugarcane vinasse under increasing organic loads (2.4-18.0kgCODm(-3)day(-1)) was assessed, focusing on the impacts of the different media arrangements over the production and retention of biomass. Much higher organic matter degradation rates, as well as long-term operational stability and high conversion efficiencies (>80%) confirmed that the FVR performed better than the PBR. Despite the equivalent operating conditions, the biomass growth yield was different in both reactors, i.e., 0.095gVSSg(-1)COD (FVR) and 0.066gVSSg(-1)COD (PBR), indicating a clear control of the media arrangement over the biomass production in fixed-bed reactors.

  19. Evaluation of volcanic pumice stone as media in fixed bed sequence batch reactor for atrazine removal from aquatic environments.

    PubMed

    Derakhshan, Zahra; Ehrampoush, Mohammad Hassan; Mahvi, Amir Hossein; Faramarzian, Mohammad; Mokhtari, Mehdi; Mazloomi, Seyed Mohammad

    2016-12-01

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) is a component of S-triazine. Its characteristics make it a pollutant of ecosystems and a probable human carcinogen. The present study evaluated volcanic pumice stone as a suitable media for biological growth and biofilm development in a fixed-bed sequencing batch reactor (FBSBR) for atrazine removal from aquatic environments. The FBSBR was fed with synthetic wastewater containing sucrose and atrazine at four hydraulic retention times to assess biodegradation of atrazine by a microbial consortium for removal from aquatic environments. The maximum efficiency for atrazine and soluble chemical oxygen demand removal were 97.9% and 98.9%, respectively. The results of this research showed that the Stover-Kincannon model was a very good fit (R(2) > 99%) for loading atrazine onto the FBSBR. Increasing the initial concentration of atrazine increased the removal efficiency. There was no significant inhibition of the mixed aerobic microbial consortia by the atrazine. Atrazine degradation depended on its initial concentration in the wastewater and the amount of atrazine in the influent. Although this system shows good potential for atrazine removal from aqueous environments, that remaining in the effluent does not yet meet international standards. Further research is required to make this system effective for removal of atrazine from the environment.

  20. Application of acidogenic fixed-bed reactor prior to anaerobic membrane bioreactor for sustainable slaughterhouse wastewater treatment.

    PubMed

    Saddoud, Ahlem; Sayadi, Sami

    2007-11-19

    High rate anaerobic treatment systems such as anaerobic membrane bioreactors (AMBR) are less popular for slaughterhouse wastewater due to the presence of high fat oil and suspended matters in the effluent. This affects the performance and efficiency of the treatment system. In this work, AMBR has been tried for slaughterhouse wastewater treatment. After the start up period, the reactor was operated with an average organic loading rate (OLR) of 4.37 kg TCODm(-3)d(-1) with gradual increase to an average of 13.27 kg TCODm(-3)d(-1). At stable conditions, the treatment efficiency was high with an average COD and BOD(5) reduction of 93.7 and 93.96%, respectively. However, a reduction in the AMBR performance was shown with the increase of the OLR to 16.32 kg TCODm(-3)d(-1). The removal efficiencies of SCOD and BOD(5) were drastically decreased to below 53.6 and 73.3%, respectively. The decrease of the AMBR performance was due to the accumulation of VFAs. Thus, a new integrated system composed of a FBR for the acidogenesis step followed by the AMBR for methanogenesis step was developed. At high ORL, the integrated system improved the performance of the anaerobic digestion and it successfully overcame the VFA accumulation problem in the AMBR. The anaerobic treatment led to a total removal of all tested pathogens. Thus, the microbiological quality of treated wastewater fits largely with WHO guidelines.

  1. Assessment of a microalgae pond for post-treatment of the effluent from an anaerobic fixed bed reactor treating distillery wastewater.

    PubMed

    Travieso, L; Benítez, F; Sánchez, E; Borja, R; León, M; Raposo, F; Rincón, B

    2008-09-01

    An evaluation of the performance of a laboratory-scale microalgae pond treating effluent from an anaerobic fixed bed reactor digesting distillery wastewater was carried out. The microalgae pond operated with an effluent recycling (R) of 10:1 with respect to the influent and at surface organic loading rates of 418 kg COD ha(-1) day(-1) and 92 kg BOD5 ha(-1) day(-1). During the experiment total chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total solids (TS), total suspended solids (TSS), volatile suspended solids (VSS), total nitrogen, ammonia, total phosphorus, orthophosphate, total chlorophyll (CT) and chlorophyll a (Ca) concentrations were monitored. Overall COD and BOD5 removal efficiencies of 98.2% and 98.8% were obtained. The global solids removal efficiencies were of 93.2%, 92.6% and 97.6% for TS, TSS and VSS, respectively. The removal efficiencies obtained for organic nitrogen and ammonia were 90.2% and 84.1%, respectively. Finally, the removals for total phosphorus and orthophosphate were 85.5% and 87.3%, respectively. It was demonstrated that microalgae grew in this waste by determination of the total chlorophyll and chlorophyll a in the effluent.

  2. Performance of up-flow anaerobic fixed bed reactor of the treatment of sugar beet pulp lixiviation in a thermophilic range.

    PubMed

    Montañés Alonso, Rocío; Pérez García, Montserrat; Solera del Río, Rosario

    2014-02-01

    The acclimatization and performance study of lixiviation of sugar beet pulp are carried out in upflow anaerobic fixed bed reactor in thermophilic range of temperature (55°C). Several hydraulic retention time is conducted (11, 8, 6, 4, 2, and 1.5 days). The performance study showed that Chemical Oxygen Demand removal efficiency is 90% for 6 days-HRT. While COD removal efficiency was reduced within the range of 74.3% and 59.4% in others HRT. Organic loading rates greater than 10 kg COD/m(3)d in influent, (2 days-HRT), produces a destabilization of the process due to total acidity accumulation in reactors although is the HRT with highest methane production. The results showed that an increase in OLR was directly correlated with active biomass inside reactor but not with the amount in microbial community. The bacterial concentration inside the reactor is strongly influenced by the content of microorganisms in the lixiviation of sugar beet pulp.

  3. Effects of lipids and oleic acid on biomass development in anaerobic fixed-bed reactors. Part II: Oleic acid toxicity and biodegradability.

    PubMed

    Alves, M M; Vieira, J A; Pereira, R M; Pereira, M A; Mota, M

    2001-01-01

    Oleic acid toxicity and biodegradability were followed during long-term operation of two similar anaerobic fixed-bed units. When treating an oleate based effluent, the sludge from the bioreactor that was acclimated with lipids during the first operation period, showed a higher tolerance to oleic acid toxicity (IC50 = 137 mg/l) compared with the sludge fed with a non-fat substrate (IC50 = 80 mg/l). This sludge showed also the highest biodegradation capacity of oleic acid, achieving maximum methane production rates between 33 and 46 mlCH4(STP)/gVS.day and maximum percentages of methanization between 85 and 98% for the range of concentrations between 500 and 900 mg oleate/l. When oleate was the sole carbon source fed to both digesters, the biomass became encapsulated with organic matter, possibly oleate or an intermediate of its degradation, e.g. stearate that was degraded at a maximum rate of 99 mlCH4(STP)/gVS.day. This suggests the possibility of using adsorption-degradation cycles for the treatment of LCFA based effluents. Both tolerance to toxicity and biodegradability of oleic acid were improved by acclimatization with lipids or oleate below a threshold concentration.

  4. Effect of air-assisted backwashing on the performance of an anaerobic fixed-bed bioreactor that simultaneously removes nitrate and arsenic from drinking water sources.

    PubMed

    Upadhyaya, Giridhar; Clancy, Tara M; Snyder, Kathryn V; Brown, Jess; Hayes, Kim F; Raskin, Lutgarde

    2012-03-15

    Contaminant removal from drinking water sources under reducing conditions conducive for the growth of denitrifying, arsenate reducing, and sulfate reducing microbes using a fixed-bed bioreactor may require oxygen-free gas (e.g., N2 gas) during backwashing. However, the use of air-assisted backwashing has practical advantages, including simpler operation, improved safety, and lower cost. A study was conducted to evaluate whether replacing N2 gas with air during backwashing would impact performance in a nitrate and arsenic removing anaerobic bioreactor system that consisted of two biologically active carbon reactors in series. Gas-assisted backwashing, comprised of 2 min of gas injection to fluidize the bed and dislodge biomass and solid phase products, was performed in the first reactor (reactor A) every two days. The second reactor (reactor B) was subjected to N2 gas-assisted backwashing every 3-4 months. Complete removal of 50 mg/L NO3- was achieved in reactor A before and after the switch from N2-assisted backwashing (NAB) to air-assisted backwashing (AAB). Substantial sulfate removal was achieved with both backwashing strategies. Prolonged practice of AAB (more than two months), however, diminished sulfate reduction in reactor B somewhat. Arsenic removal in reactor A was impacted slightly by long-term use of AAB, but arsenic removals achieved by the entire system during NAB and AAB periods were not significantly different (p>0.05) and arsenic concentrations were reduced from approximately 200 μg/L to below 20 μg/L. These results indicate that AAB can be implemented in anaerobic nitrate and arsenic removal systems.

  5. A combined upflow anaerobic sludge bed, aerobic, and anoxic fixed-bed reactor system for removing tetramethylammonium hydroxide and nitrogen from light-emitting diode wastewater.

    PubMed

    Lin, Han-Lin; Chen, Sheng-Kun; Huang, Yu-Wen; Chen, Wei-Cheng; Chien, Wei-Cheng; Cheng, Sheng-Shung

    2016-01-01

    A laboratory study using a combined upflow anaerobic sludge bed (UASB) and aerobic and anoxic fixed-bed reactor system was undertaken to explore its capability for removing tetramethylammonium hydroxide (TMAH) and nitrogen from light-emitting diode wastewater. When the organic loading rate was maintained at 0.26-0.65 kg TMAH m(-3 )d(-1), the UASB reactor removed 70-100% of TMAH through methanogenesis. When the [Formula: see text] -N loading rate was maintained at 0.73-1.4 kg [Formula: see text]-N m(-3 )d(-1), the aerobic reactor oxidized 31-59% of [Formula: see text]-N to [Formula: see text]-N through nitritation. When the nitrogen loading rate was maintained at 0.42-0.75 kg N m(-3 )d(-1), the anoxic reactor removed 27-63% of nitrogen through anammox. The performance data of the combined reactor system agreed well with the stoichiometric relationships of methanogenesis, nitritation, and anammox. The batch studies showed that a higher initial TMAH concentration of up to 2520 mg L(-1) gave a higher methanogenic activity of up to 16 mL CH4 g(-1) VSS d(-1). An increase in the initial TMAH concentration of up to 500 mg L(-1) gradually decreased the activity of ammonia-oxidizing bacteria; whereas an increase in the initial TMAH concentration of up to 47 mg L(-1) imposed a marked inhibiting effect on the activity of anammox bacteria.

  6. A comparative study of anaerobic fixed film baffled reactor and up-flow anaerobic fixed film fixed bed reactor for biological removal of diethyl phthalate from wastewater: a performance, kinetic, biogas, and metabolic pathway study.

    PubMed

    Yousefzadeh, Samira; Ahmadi, Ehsan; Gholami, Mitra; Ghaffari, Hamid Reza; Azari, Ali; Ansari, Mohsen; Miri, Mohammad; Sharafi, Kiomars; Rezaei, Soheila

    2017-01-01

    Phthalic acid esters, including diethyl phthalate (DEP), which are considered as top-priority and hazardous pollutants, have received significant attention over the last decades. It is vital for industries to select the best treatment technology, especially when the DEP concentration in wastewater is high. Meanwhile, anaerobic biofilm-based reactors are considered as a promising option. Therefore, in the present study, for the biological removal of DEP from synthetic wastewater, two different anaerobic biofilm-based reactors, including anaerobic fixed film baffled reactor (AnFFBR) and up-flow anaerobic fixed film fixed bed reactor (UAnFFFBR), were compared from kinetic and performance standpoints. As in the previous studies, only the kinetic coefficients have been calculated and the relationship between kinetic coefficients and their interpretation has not been evaluated, the other aim of the present study was to fill this research gap. In optimum conditions, 90.31 and 86.91% of COD as well as 91.11 and 88.72% of DEP removal were achieved for the AnFFBR and UAnFFFBR, respectively. According to kinetic coefficients (except biomass yield), the AnFFBR had better performance as it provided a more favorable condition for microbial growth. The Grau model was selected as the best mathematical model for designing and predicting the bioreactors' performance due to its high coefficients of determination (0.97 < R(2)). With regard to the insignificant variations of the calculated Grau kinetic coefficients (KG) when the organic loading rate (with constant HRT) increased, it can be concluded that both of the bioreactors can tolerate high organic loading rate and their performance is not affected by the applied DEP concentrations. Both the bioreactors were capable of treating low-to-high strength DEP wastewater; however, according to the experimental results and obtained kinetic coefficients, the AnFFBR indicated higher performance. Although the AnFFBR can be considered as a

  7. Treatment of screened dairy manure by upflow anaerobic fixed bed reactors packed with waste tyre rubber and a combination of waste tyre rubber and zeolite: effect of the hydraulic retention time.

    PubMed

    Umaña, Oscar; Nikolaeva, Svetlana; Sánchez, Enrique; Borja, Rafael; Raposo, Francisco

    2008-10-01

    Two laboratory-scale anaerobic fixed bed reactors were evaluated while treating dairy manure at upflow mode and semicontinuous feeding. One reactor was packed with a combination of waste tyre rubber and zeolite (R1) while the other had only waste tyre rubber as a microorganism immobilization support (R2). Effluent quality improved when the hydraulic retention time (HRT) increased from 1.0 to 5.5 days. Higher COD, BOD5, total and volatile solids removal efficiencies were always achieved in the reactor R1. No clogging was observed during the operation period. Methane yield was also a function of the HRT and of the type of support used, and was 12.5% and 40% higher in reactor R1 than in R2 for HRTs of 5.5 and 1.0 days, respectively. The results obtained demonstrated that this type of reactor is capable of operating with dairy manure at a HRT 5 times lower than that used in a conventional reactor.

  8. Updraft Fixed Bed Gasification Aspen Plus Model

    SciTech Connect

    2007-09-27

    The updraft fixed bed gasification model provides predictive modeling capabilities for updraft fixed bed gasifiers, when devolatilization data is available. The fixed bed model is constructed using Aspen Plus, process modeling software, coupled with a FORTRAN user kinetic subroutine. Current updraft gasification models created in Aspen Plus have limited predictive capabilities and must be "tuned" to reflect a generalized gas composition as specified in literature or by the gasifier manufacturer. This limits the applicability of the process model.

  9. Upflow fixed bed bioelectrochemical reactor for wastewater treatment applications.

    PubMed

    González-Gutiérrez, Linda; Frontana, Carlos; Martínez, Eduardo

    2015-01-01

    A cylindrical Upflow Fixed Bed Reactor (UFB-BER) with granular activated carbon, steel mesh electrodes and anaerobic microorganisms, was constructed for analyzing how hydrodynamic parameters affect the reactions involved during wastewater treatment processes for azo dye degradation. Dye removal percentage was not compromised by decreasing HRTm (99-90% upon changing HRTm from 4 to 1h in single pass mode). Using the residence time distribution method for hydrodynamic characterization, it was found that a higher dispersion in the reactor occurs for HRTm=1h, than for HRTm=4h. A kinetic analysis suggests that this dispersion effect could be associated to a higher specific reaction rate dependent on the azo dye concentration.

  10. Apparatus for fixed bed coal gasification

    DOEpatents

    Sadowski, Richard S.

    1992-01-01

    An apparatus for fixed-bed coal gasification is described in which coal such as caking coal is continuously pyrolyzed with clump formation inhibited, by combining the coal with a combustible gas and an oxidant, and then continually feeding the pyrolyzed coal under pressure and elevated temperature into the gasification region of a pressure vessel. The materials in the pressure vessel are allowed to react with the gasifying agents in order to allow the carbon contents of the pyrolyzed coal to be completely oxidized. The combustion of gas produced from the combination of coal pyrolysis and gasification involves combining a combustible gas coal and an oxidant in a pyrolysis chamber and heating the components to a temperature of at least 1600.degree. F. The products of coal pyrolysis are dispersed from the pyrolyzer directly into the high temperature gasification region of a pressure vessel. Steam and air needed for gasification are introduced in the pressure vessel and the materials exiting the pyrolyzer flow down through the pressure vessel by gravity with sufficient residence time to allow any carbon to form carbon monoxide. Gas produced from these reactions are then released from the pressure vessel and ash is disposed of.

  11. Isolated thermocouple amplifier system for stirred fixed-bed gasifier

    DOEpatents

    Fasching, George E.

    1992-01-01

    A sensing system is provided for determining the bed temperature profile of the bed of a stirred, fixed-bed gasifier including a plurality of temperature sensors for sensing the bed temperature at different levels, a transmitter for transmitting data based on the outputs of the sensors to a remote operator's station, and a battery-based power supply. The system includes an isolation amplifier system comprising a plurality of isolation amplifier circuits for amplifying the outputs of the individual sensors. The isolation amplifier circuits each comprise an isolation operational amplifier connected to a sensor; a first "flying capacitor" circuit for, in operation, controlling the application of power from the power supply to the isolation amplifier; an output sample and hold circuit connected to the transmitter; a second "flying capacitor" circuit for, in operation, controlling the transfer of the output of the isolation amplifier to the sample and hold circuit; and a timing and control circuit for activating the first and second capacitor circuits in a predetermined timed sequence.

  12. Drop Breakup in the Flow Through Fixed Beds

    NASA Astrophysics Data System (ADS)

    Mosler, Alisa B.; Shaqfeh, Eric S. G.

    1996-11-01

    The flow through a dilute, disordered fixed bed of fibers has been shown to produce large polymer conformation change beyond a certain critical flow rate^1. We now examine the effect of this flow on the shape and breakup of viscous drops. The stochastic, Lagrangian time-varying flow through fixed beds is of particular interest since it may efficiently induce drop fragmentation and is used as a practical means of emulsification and the mixing of liquid phases. Because the flow through a dilute fixed bed is equivalent to a certain anisotropic Gaussian flow field^1, a model of the flow is reproduced through a spectral expansion where the wave number vectors are chosen from statistical distributions which ensure that the desired velocity field will be realized^2. We examine the dynamics of model drop shapes (whose surface is represented via small deformation theory^3, 4), averaged over the Gaussian statistics of the flow field, by synthesizing a large number of flow realizations. We demonstrate that the flow through fixed beds is indeed ``strong'' since beyond a certain value of the pore-size Capillary number, Ca ~ 0.2, no steady average solution for the drop shape exists. We shall go on to discuss the mechanisms of this flow-induced breakup. ^1 Shaqfeh and Koch (1992), ^2 Mosler and Shaqfeh (1996), ^3 Taylor (1932, 1934), ^4 Barthès-Biesel and Acrivos (1973)

  13. Heterogeneous decomposition of silane in a fixed bed reactor

    NASA Technical Reports Server (NTRS)

    Iya, S. K.; Flagella, R. N.; Dipaolo, F. S.

    1982-01-01

    Heterogeneous decomposition of silane in a fluidized bed offers an attractive route for the low-cost production of silicon for photovoltaic application. To obtain design data for a fluid bed silane pyrolysis reactor, deposition experiments were conducted in a small-scale fixed bed apparatus. Data on the decomposition mode, plating rate, and deposition morphology were obtained in the temperature range 600-900 C. Conditions favorable for heterogeneous decomposition with good deposition morphology were identified. The kinetic rate data showed the reaction to be first order with an activation energy of 38.8 kcal/mol, which agrees well with work done by others. The results are promising for the development of an economically attractive fluid bed process.

  14. Heterogeneous decomposition of silane in a fixed bed reactor

    NASA Technical Reports Server (NTRS)

    Iya, S. K.; Flagella, R. N.; Dipaolo, F. S.

    1981-01-01

    Heterogeneous decomposition of silane in a fluidized bed offers an attractive route for the low-cost production of silicon for photovoltaic application. To obtain design data for a fluid bed silane pyrolysis reactor, deposition experiments were conducted in a small-scale fixed bed apparatus. Data on the decomposition mode, plating rate, and deposition morphology were obtained in the temperature range 600 900 C. Conditions favorable for heterogenous decomposition with good deposition morphology were identified. The kinetic rate data showed the reaction to be first order with an activation energy of 38.8 kcal/mole, which agrees well with work done by others. The results are promising for the development of an economically attractive fluid bed process.

  15. Grate assembly for fixed-bed coal gasifier

    DOEpatents

    Notestein, John E.

    1993-01-01

    A grate assembly for a coal gasifier of a moving-bed or fixed-bed type is provided for crushing agglomerates of solid material such as clinkers, tailoring the radial distribution of reactant gases entering the gasification reaction zone, and control of the radial distribution of downwardly moving solid velocities in the gasification and combustion zone. The clinker crushing is provided by pinching clinkers between vertically oriented stationary bars and angled bars supported on the upper surface of a rotating conical grate. The distribution of the reactant gases is provided by the selective positioning of horizontally oriented passageways extending through the grate. The radial distribution of the solids is provided by mounting a vertically and generally radially extending scoop mechanism on the upper surface of the grate near the apex thereof.

  16. Automation of a fixed-bed continuous–flow reactor

    PubMed Central

    Alcántara, R.; Canoira, L.; Conde, R.; Fernández-Sánchez, J. M.; Navarro, A.

    1994-01-01

    This paper describes the design and operation of a laboratory plant with a fixed-bed continuous-flow reactor, fully automated and controlled from a personal computer. The automated variables include two gas flows, one liquid flow, six temperatures, two pressures, one circulation of a cooling liquid, and 10 electrovalves. An adaptive-predictive control system was used. The chemical process chosen to run the automated reactor was the conversion of methanol to gasoline over a ZSM-5 catalyst. This is a highly exothermal process, so a cascade control system had to be used to control the reactor internal temperature. Pressure and weight hourly space velocity (WHSV) were fixed at 1 arm and 1.5h-1 respectively. Accurate control (±0.2°C) of the reactor’s internal temperature was achieved and repeatability for the conversion of methanol to gasoline was good. PMID:18924990

  17. Heterogeneous decomposition of silane in a fixed bed reactor

    NASA Technical Reports Server (NTRS)

    Iya, S. K.; Flagella, R. N.; Dipaolo, F. S.

    1981-01-01

    Heterogeneous decomposition of silane in a fluidized bed offers an attractive route for the low-cost production of silicon for photovoltaic application. To obtain design data for a fluid bed silane pyrolysis reactor, deposition experiments were conducted in a small-scale fixed bed apparatus. Data on the decomposition mode, plating rate, and deposition morphology were obtained in the temperature range 600 900 C. Conditions favorable for heterogenous decomposition with good deposition morphology were identified. The kinetic rate data showed the reaction to be first order with an activation energy of 38.8 kcal/mole, which agrees well with work done by others. The results are promising for the development of an economically attractive fluid bed process.

  18. Heterogeneous decomposition of silane in a fixed bed reactor

    NASA Technical Reports Server (NTRS)

    Iya, S. K.; Flagella, R. N.; Dipaolo, F. S.

    1982-01-01

    Heterogeneous decomposition of silane in a fluidized bed offers an attractive route for the low-cost production of silicon for photovoltaic application. To obtain design data for a fluid bed silane pyrolysis reactor, deposition experiments were conducted in a small-scale fixed bed apparatus. Data on the decomposition mode, plating rate, and deposition morphology were obtained in the temperature range 600-900 C. Conditions favorable for heterogeneous decomposition with good deposition morphology were identified. The kinetic rate data showed the reaction to be first order with an activation energy of 38.8 kcal/mol, which agrees well with work done by others. The results are promising for the development of an economically attractive fluid bed process.

  19. Fixed-bed bioreactor system for the microbial solubilization of coal

    DOEpatents

    Scott, C.D.; Strandberg, G.W.

    1987-09-14

    A fixed-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fixed-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the large scale production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fixed-bed bioreactor. 1 fig., 1 tab.

  20. Ash level meter for a fixed-bed coal gasifier

    DOEpatents

    Fasching, George E.

    1984-01-01

    An ash level meter for a fixed-bed coal gasifier is provided which utilizes the known ash level temperature profile to monitor the ash bed level. A bed stirrer which travels up and down through the extent of the bed ash level is modified by installing thermocouples to measure the bed temperature as the stirrer travels through the stirring cycle. The temperature measurement signals are transmitted to an electronic signal process system by an FM/FM telemetry system. The processing system uses the temperature signals together with an analog stirrer position signal, taken from a position transducer disposed to measure the stirrer position to compute the vertical location of the ash zone upper boundary. The circuit determines the fraction of each total stirrer cycle time the stirrer-derived bed temperature is below a selected set point, multiplies this fraction by the average stirrer signal level, multiplies this result by an appropriate constant and adds another constant such that a 1 to 5 volt signal from the processor corresponds to a 0 to 30 inch span of the ash upper boundary level. Three individual counters in the processor store clock counts that are representative of: (1) the time the stirrer temperature is below the set point (500.degree. F.), (2) the time duration of the corresponding stirrer travel cycle, and (3) the corresponding average stirrer vertical position. The inputs to all three counters are disconnected during any period that the stirrer is stopped, eliminating corruption of the measurement by stirrer stoppage.

  1. Countercurrent fixed-bed gasification of biomass at laboratory scale

    SciTech Connect

    Di Blasi, C.; Signorelli, G.; Portoricco, G.

    1999-07-01

    A laboratory-scale countercurrent fixed-bed gasification plant has been designed and constructed to produce data for process modeling and to compare the gasification characteristics of several biomasses (beechwood, nutshells, olive husks, and grape residues). The composition of producer gas and spatial temperature profiles have been measured for biomass gasification at different air flow rates. The gas-heating value always attains a maximum as a function of this operating variable, associated with a decrease of the air-to-fuel ratio. Optical gasification conditions of wood and agricultural residues give rise to comparable gas-heating values, comprised in the range 5--5.5 MJ/Nm{sup 3} with 28--30% CO, 5--7% CO{sub 2}, 6--8% H{sub 2}, 1--2% CH{sub 4}, and small amounts of C{sub 2}- hydrocarbons (apart from nitrogen). However, gasification of agricultural residues is more difficult because of bed transport, partial ash sintering, nonuniform flow distribution, and the presence of a muddy phase in the effluents, so that proper pretreatments are needed for largescale applications.

  2. Intrinsic kinetics for fixed bed bioreactor in hospital wastewater treatment.

    PubMed

    Farrokhi, Mehrdad; Mahdavianpour, Mostafa; Shirzad-Siboni, Mehdi; Naimi-Joubani, Mohammad; Jamali, Hamzeh Ali

    2016-10-01

    Variation in hospital wastewater (HWW) pollutants and differences with municipal wastewater (MWW), make the use of biokinetic coefficients obtained from activated sludge in the MWW treatment unprofitable for designing, modeling and evaluation of biological processes for HWW treatment. Since this study was conducted to evaluate the performance and biokinetic coefficients of a fixed bed bioreactor (FBBR) using rice husks as fixed media in HWW treatment, a new modified method was also proposed for biokinetic estimation in FBBR processes. For these purposes, five hydraulic retention times along with five sludge retention times were introduced to a pilot setup and the required data were attained. The performance process for chemical oxygen demand (COD) removal was significant (87.8-97.5%) in different conditions. The values of biokinetic coefficients k, Ks, Y and Kd were obtained as 2.42 (day(-1)), 55.5 (mgCOD/L), 0.2929 (mgBiomass/mgCOD) and 0.0164 (day(-1)), respectively. The rice husks with high surface area and high affinity for biomass accumulation on its surface are promising media for a green and environmentally friendly FBBR process. The kinetics parameters values are utilizable for modeling of FBBR using rice husks as fixed media in HWW treatment.

  3. Biohydrogen production from tequila vinasses using a fixed bed reactor.

    PubMed

    Buitrón, Germán; Prato-Garcia, Dorian; Zhang, Axue

    2014-01-01

    In Mexico, the industrial production of tequila leads to the discharge of more than 31.2 million of m(3) of vinasse, which causes serious environmental issues because of its acidity, high organic load and the presence of recalcitrant compounds. The aim of this research was to study the feasibility of a fixed bed reactor for the production of biohydrogen by using tequila vinasse as substrate. The experiments were carried out in a continuous mode under mesophilic and acidic conditions. The maximum hydrogen yield and hydrogen production rate were 1.3 mol H2 mol/mol glucose and 72 ± 9 mL H2/(Lreactor h), respectively. Biogas consisted of carbon dioxide (36%) and hydrogen (64%); moreover methane was not observed. The electron-equivalent mass balance fitted satisfactorily (sink of electrons from 0.8 to 7.6%). For vinasses, hydrogen production accounted for 10.9% of the total available electron-equivalents. In the liquid phase, the principal metabolites identified were acetic, butyric and iso-butyric acids, which indicated a butyrate-acetate type fermentation. Tequila vinasses did not result in potential inhibition of the fermentative process. Considering the process as a water treatment system, only 20% of the original carbon was removed (as carbon dioxide and biomass) when the tequila vinasses are used.

  4. Numerical modeling of a deep, fixed bed combustor

    SciTech Connect

    Bryden, K.M.; Ragland, K.W.

    1995-12-31

    A steam power plant utilizing whole trees as the renewable fuel (Whole-Tree-Energy{trademark}) is being developed by Energy Performances Systems, Inc. of Minneapolis, MN. Hardwood trees are grown and harvested on energy plantations, or harvested from inferior, over-aged standing trees, transported in trucks as whole trees, and stored in a large covered stack at the power plant site where the stack is dried with waste heat from the power plant. When dried to the desired moisture content, the whole trees are burned in a fixed bed boiler. This innovative system completed stacking, drying and combustion tests at a site near Aurora, MN in August, 1992. The advantages of the proposed system are (1) time, energy and processing costs are saved by not chipping the wood, (2) a 30 day supply of wood may be stored on site without degradation of the fuel, and (3) the combustion heat release per unit plan area is greater than with wood chips. The concept is envisioned for 25 MW to 400 MW Rankine cycle power plants.

  5. Influence of cooling design on fixed-bed reactors dynamics

    SciTech Connect

    Buccala, V.; Borio, D.O.; Romagnoli, J.A.; Porras, J.A. )

    1992-12-01

    Tubular fixed-bed reactors of the heat-exchanger type are selected commonly in industrial plants to carry out highly exothermic reactions. Due to the important heat effects involved, these units usually exhibit the well-known problems of a pronounced maximum in the axial temperature profile (hot spot), combined with high parametric sensitivity. The authors analyzed the response of axial temperature and concentration profiles to changes in the reactant's inlet conditions for the cocurrent design. Nevertheless, more critical disturbances are changes at the inlet coolant temperature which is often used as an indirect manipulated variable for control purposes. Therefore, the influence of this variable on the reactor dynamics will be studied in this paper. Recent steady-state simulation results have shown that the behavior of this type of reactors depends strongly on the mutual direction of the reacting fluid and coolant streams. As optimal operation conditions cannot be defined only on the basis of steady-state analysis, this work complements the above-mentioned works by means of a similar development, performed under nonsteady-state conditions. The underlying idea is that to be confirmed as the best choice, the optimal design found from steady-state analysis should demonstrate also to exhibit an acceptable dynamic performance.

  6. Comparison of slurry versus fixed-bed reactor costs for indirect liquefaction applications

    SciTech Connect

    Prakash, A.; Bendale, P.G.

    1991-12-01

    This work is a comparative evaluation of slurry reactors and fixed-bed reactors, with special emphasis on cost. Relative differences between slurry reactors and fixed-bed reactors have been pointed out in previous reviews; the differences pertinent to indirect liquefaction are summarized here. Design of both types is outlined.

  7. Kinetics studies of uranium sorption by powdered corn cob in batch and fixed bed system

    PubMed Central

    Mahmoud, Mohamed A.

    2015-01-01

    Sorption of uranium (VI) from aqueous solution onto powdered corn cob has been carried out using batch and fixed-bed technique. The experimental results in batch technique were fitted well with pseudo second-order kinetics model. In the fixed bed technique, Thomas and Bohart–Adams models were evaluated by linear regression analysis for U(VI) uptake in different flow rates, bed heights and initial concentrations. The column experimental data were fitted well with Thomas mode (r2 = 0.999), but the Bohart–Adams model (r2 = 0.911), predicted poor performance of fixed-bed column. PMID:26843973

  8. Air gasification of biogas-derived digestate in a downdraft fixed bed gasifier.

    PubMed

    Chen, Guanyi; Guo, Xiang; Cheng, Zhanjun; Yan, Beibei; Dan, Zeng; Ma, Wenchao

    2017-08-22

    Digestate is a byproduct from biomass anaerobic digestion process. Gasification of dried digestate to produce gasesous product might be a promising route. In this work, air gasification of digestate with high ash content was performed in a downdraft fixed bed gasifier at temperature varying from 600°C to 800°C and air equivalence ratio (ER) ranging from 0.25 to 0.30. The ash melting properties were firstly detected by the Intelligent Ash Melting Point Test, and the by-products (biochar and ash) were analyzed. The results showed that no ash slagging was observed and therefore it is feasible to operate digestate gasification under 800°C and ER ranging from 0.25 to 0.30. High temperature favored gas production, 800°C is proposed for digestate gasification in the present study. ER with a medium value improved gas quality and cold gas efficiency (CGE), and the optimal LHV of 4.78MJ/Nm(3) and CGE of 67.01% were obtained with ER of 0.28. High ER favored the increase of gas yield and decrease of tar concentration, and the optimal gas yield of 2.15 Nm(3)/kg and tar concentration of 1.61g/Nm(3) were achieved with ER of 0.30. Improved molar ratio of H2/CO varying from 1.03 to 1.08 was obtained at 800°C, indicating gaseous product has the potential for chemical synthesis processes (1

  9. Fixed-bed gasification research using US coals. Volume 13. Gasification of Blind Canyon bituminous coal

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-05-01

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report is the thirteenth volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This specific report describes the gasification of Blind Canyon bituminous coal, from July 31, 1984 to August 11, 1984. 6 refs., 22 figs., 20 tabs.

  10. Fixed-bed gasification research using US coals. Volume 10. Gasification of Benton lignite

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-05-01

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report is the tenth volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This specific report describes the gasification of Benton lignite. The period of gasification test was November 1-8, 1983. 16 refs., 22 figs., 19 tabs.

  11. Pretreatment of coking wastewater using anaerobic sequencing batch reactor (ASBR)*

    PubMed Central

    Li, Bing; Sun, Ying-lan; Li, Yu-ying

    2005-01-01

    A laboratory-scale anaerobic sequencing batch reactor (ASBR) was used to pretreat coking wastewater. Inoculated anaerobic granular biomass was acclimated for 225 d to the coking wastewater, and then the biochemical methane potential (BMP) of the coking wastewater in the acclimated granular biomass was measured. At the same time, some fundamental technological factors, such as the filling time and the reacting time ratio (t f/t r), the mixing intensity and the intermittent mixing mode, that affect anaerobic pretreatment of coking wastewater with ASBR, were evaluated through orthogonal tests. The COD removal efficiency reached 38%~50% in the stable operation period with the organic loading rate of 0.37~0.54 kg COD/(m3·d) at the optimum conditions of t f/t r, the mixing intensity and the intermittent mixing mode. In addition, the biodegradability of coking wastewater distinctly increased after the pretreatment using ASBR. At the end of the experiment, the microorganism forms on the granulated sludge in the ASBR were observed using SEM (scanning electron microscope) and fluoroscope. The results showed that the dominant microorganism on the granular sludge was Methanosaeta instead of Methanosarcina dominated on the inoculated sludge. PMID:16252347

  12. Evaluation of a new fixed-bed digester design utilizing large media for flush dairy manure treatment.

    PubMed

    Zaher, Usama; Frear, Craig; Pandey, Paramod; Chen, Shulin

    2008-12-01

    A new anaerobic digester design for the treatment of diluted (<2% solids) flush dairy manure was evaluated. The new design was developed as an economic alternative for enhancing the performance of anaerobic lagoon systems in cold weather areas. The digester employed used automobile tires as fixed-bed media to improve bacterial retention. The digester was heated by steam injection and built underground to enhance insulation. The tires were sorted in a unique pattern for improving mixing and uniform temperature distribution. The system was tested on a pilot-scale. The treatment mechanism was explored by mathematical modeling. The observed treatment efficiency of the new design was comparable to that of conventional digesters operating at higher total solids concentrations (>4%). With a hydraulic retention time (HRT) of 17 days, the measured removal rates were 30-50% and 40-60% of TVS and COD, respectively. The new digester maintained longer solids retention time (SRT) as estimated using the model, supported by the observed thick biofilm formation and resistance to hydraulic overload. The model was used to analyze different operation scenarios varying both the organic and hydraulic loads.

  13. The effect of biological sulfate reduction on anaerobic color removal in anaerobic-aerobic sequencing batch reactors.

    PubMed

    Cirik, Kevser; Kitis, Mehmet; Cinar, Ozer

    2013-05-01

    Combination of anaerobic-aerobic sequencing processes result in both anaerobic color removal and aerobic aromatic amine removal during the treatment of dye-containing wastewaters. The aim of the present study was to gain more insight into the competitive biochemical reactions between sulfate and azo dye in the presence of glucose as electron donor source. For this aim, anaerobic-aerobic sequencing batch reactor fed with a simulated textile effluent including Remazol Brilliant Violet 5R (RBV 5R) azo dye was operated with a total cycle time of 12 h including anaerobic (6 h) and aerobic cycles (6 h). Microorganism grown under anaerobic phase of the reactor was exposed to different amounts of competitive electron acceptor (sulfate). Performance of the anaerobic phase was determined by monitoring color removal efficiency, oxidation reduction potential, color removal rate, chemical oxygen demand (COD), color, specific anaerobic enzyme (azo reductase) and aerobic enzyme (catechol 1,2-dioxygenase), and formation of aromatic amines. The presence of sulfate was not found to significantly affect dye decolorization. Sulfate and azo dye reductions took place simultaneously in all operational conditions and increase in the sulfate concentration generally stimulated the reduction of RBV 5R. However, sulfate accumulation under anaerobic conditions was observed proportional to increasing sulfate concentration.

  14. Genome sequence of the stramenopile Blastocystis, a human anaerobic parasite

    PubMed Central

    2011-01-01

    Background Blastocystis is a highly prevalent anaerobic eukaryotic parasite of humans and animals that is associated with various gastrointestinal and extraintestinal disorders. Epidemiological studies have identified different subtypes but no one subtype has been definitively correlated with disease. Results Here we report the 18.8 Mb genome sequence of a Blastocystis subtype 7 isolate, which is the smallest stramenopile genome sequenced to date. The genome is highly compact and contains intriguing rearrangements. Comparisons with other available stramenopile genomes (plant pathogenic oomycete and diatom genomes) revealed effector proteins potentially involved in the adaptation to the intestinal environment, which were likely acquired via horizontal gene transfer. Moreover, Blastocystis living in anaerobic conditions harbors mitochondria-like organelles. An incomplete oxidative phosphorylation chain, a partial Krebs cycle, amino acid and fatty acid metabolisms and an iron-sulfur cluster assembly are all predicted to occur in these organelles. Predicted secretory proteins possess putative activities that may alter host physiology, such as proteases, protease-inhibitors, immunophilins and glycosyltransferases. This parasite also possesses the enzymatic machinery to tolerate oxidative bursts resulting from its own metabolism or induced by the host immune system. Conclusions This study provides insights into the genome architecture of this unusual stramenopile. It also proposes candidate genes with which to study the physiopathology of this parasite and thus may lead to further investigations into Blastocystis-host interactions. PMID:21439036

  15. Adsorption of ciprofloxacin and norfloxacin from aqueous solution onto granular activated carbon in fixed bed column.

    PubMed

    Darweesh, Teeba M; Ahmed, Muthanna J

    2017-04-01

    Carbonization of Phoenix dactylifera L stones followed by microwave K2CO3 activation was adopted for preparation of granular activated carbon (KAC). High yield and favorable pore characteristics in terms of surface area and pore volume were reported for KAC as follows: 44%, 852m(2)/g, and 0.671cm(3)/g, respectively. The application of KAC as adsorbent for attraction of ciprofloxacin (CIP) and norfloxacin (NOR) was investigated using fixed bed systems. The effect of flow rate (0.5-1.5ml/min), bed height (15-25cm), and initial drug concentration (75-225mg/l) on the behavior of breakthrough curves was explained. The fixed bed analysis showed the better correlation of breakthrough data by both Thomas and Yoon-Nelson models. Inlet drug concentration was of greatest effect on breakthrough data compared to other fixed bed variables. Experimental and calculated breakthrough data were obtained for CIP and NOR adsorption on KAC, thus being important for design of fixed bed column. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

    NASA Astrophysics Data System (ADS)

    Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

    2017-05-01

    Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

  17. FIXED-BED HYDROGENATION OF ORGANIC COMPOUNDS IN SUPERCRITICAL CARBON DIOXIDE. (R826034)

    EPA Science Inventory

    Abstract

    The Pd/C hydrogenation of cyclohexene to cyclohexane was performed in a continuous fixed-bed reactor employing CO2 to solubilize the reaction mixture in a single supercritical (sc) phase surrounding the solid catalyst. Employing an equimolar feed of...

  18. APPARATUS FOR SHORT TIME MEASUREMENTS IN A FIXED-BED, GAS/SOLID REACTOR

    EPA Science Inventory

    An apparatus for exposure of a solid to reactive process gas is described which makes possible short time (≥ 0.3 to 15 s) exposures in a fixed-bed reactor. Operating conditions for differential reaction with respect to the gas concentration and rapid quench for arresting hi...

  19. Flow, turbulence, and drag associated with engineered log jams in a fixed-bed experimental channel

    USDA-ARS?s Scientific Manuscript database

    Engineered log jams (ELJs) have become attractive alternatives for river restoration and bank stabilization programs. Yet the effects of ELJs on turbulent flow and the fluid forces acting on the ELJs are not well known, and such information could inform design criteria. In this study, a fixed-bed ph...

  20. APPARATUS FOR SHORT TIME MEASUREMENTS IN A FIXED-BED, GAS/SOLID REACTOR

    EPA Science Inventory

    An apparatus for exposure of a solid to reactive process gas is described which makes possible short time (≥ 0.3 to 15 s) exposures in a fixed-bed reactor. Operating conditions for differential reaction with respect to the gas concentration and rapid quench for arresting hi...

  1. Fixed bed reactor for solid-phase surface derivatization of superparamagnetic nanoparticles.

    PubMed

    Steitz, Benedikt; Salaklang, Jatuporn; Finka, Andrija; O'Neil, Conlin; Hofmann, Heinrich; Petri-Fink, Alke

    2007-01-01

    The functionalization of nanoparticles is conditio sine qua non in studies of specific interaction with a biological target. Often, their biological functionality is achieved by covalent binding of bioactive molecules on a preexisting single surface coating. The yield and quality of the resulting coated and functionalized superparamagnetic iron oxide nanoparticles (SPIONs) can be significantly improved and reaction times reduced by using solid-phase synthesis strategies. In this study, a fixed bed reactor with a quadrupole repulsive arrangement of permanent magnets was assayed for SPION surface derivatization. The magnet array around the fixed bed reactor creates very high magnetic field gradients that enables the immobilization of SPIONs with a diameter as low as 9 nm. The functionalization on the surface of immobilized 25 nm 3-(aminopropyl)trimethoxysilane-coated SPIONs (APS-SPIONs) was performed using fluorescein-isothiocyanate directly, and by the SV40 large T-antigen nuclear localization signal peptide (PKKKRKVGC) conjugated to acryloylpoly(ethylene glycol)-N-hydroxysuccinimide, where the PEG reagent is conjugated first to create a functionalized nanoparticle and the peptide is added to the acryloyl group. We show that the yield of reactant grafted on the surface of the APS-coated SPIONs was higher in solid-phase within the fixed bed reactor compared to conventional liquid-phase chemistry. In summary, the functionalization of SPIONs using a magnetically fixed bed reactor was superior to the liquid-phase reaction in terms of the yield, reaction times required for derivatization, size distribution, and scalability.

  2. FIXED-BED HYDROGENATION OF ORGANIC COMPOUNDS IN SUPERCRITICAL CARBON DIOXIDE. (R826034)

    EPA Science Inventory

    Abstract

    The Pd/C hydrogenation of cyclohexene to cyclohexane was performed in a continuous fixed-bed reactor employing CO2 to solubilize the reaction mixture in a single supercritical (sc) phase surrounding the solid catalyst. Employing an equimolar feed of...

  3. Copper removal using a heavy-metal resistant microbial consortium in a fixed-bed reactor.

    PubMed

    Carpio, Isis E Mejias; Machado-Santelli, Glaucia; Sakata, Solange Kazumi; Ferreira Filho, Sidney Seckler; Rodrigues, Debora Frigi

    2014-10-01

    A heavy-metal resistant bacterial consortium was obtained from a contaminated river in São Paulo, Brazil and utilized for the design of a fixed-bed column for the removal of copper. Prior to the design of the fixed-bed bioreactor, the copper removal capacity by the live consortium and the effects of copper in the consortium biofilm formation were investigated. The Langmuir model indicated that the sorption capacity of the consortium for copper was 450.0 mg/g dry cells. The biosorption of copper into the microbial biomass was attributed to carboxyl and hydroxyl groups present in the microbial biomass. The effect of copper in planktonic cells to form biofilm under copper rich conditions was investigated with confocal microscopy. The results revealed that biofilm formed after 72 h exposure to copper presented a reduced thickness by 57% when compared to the control; however 84% of the total cells were still alive. The fixed-bed bioreactor was set up by growing the consortium biofilm on granular activated carbon (GAC) and analyzed for copper removal. The biofilm-GAC (BGAC) column retained 45% of the copper mass present in the influent, as opposed to 17% in the control column that contained GAC only. These findings suggest that native microbial communities in sites contaminated with heavy metals can be immobilized in fixed-bed bioreactors and used to treat metal contaminated water.

  4. Use of an anaerobic sequencing batch reactor for parameter estimation in modelling of anaerobic digestion.

    PubMed

    Batstone, D J; Torrijos, M; Ruiz, C; Schmidt, J E

    2004-01-01

    The model structure in anaerobic digestion has been clarified following publication of the IWA Anaerobic Digestion Model No. 1 (ADM1). However, parameter values are not well known, and uncertainty and variability in the parameter values given is almost unknown. Additionally, platforms for identification of parameters, namely continuous-flow laboratory digesters, and batch tests suffer from disadvantages such as long run times, and difficulty in defining initial conditions, respectively. Anaerobic sequencing batch reactors (ASBRs) are sequenced into fill-react-settle-decant phases, and offer promising possibilities for estimation of parameters, as they are by nature, dynamic in behaviour, and allow repeatable behaviour to establish initial conditions, and evaluate parameters. In this study, we estimated parameters describing winery wastewater (most COD as ethanol) degradation using data from sequencing operation, and validated these parameters using unsequenced pulses of ethanol and acetate. The model used was the ADM1, with an extension for ethanol degradation. Parameter confidence spaces were found by non-linear, correlated analysis of the two main Monod parameters; maximum uptake rate (k(m)), and half saturation concentration (K(S)). These parameters could be estimated together using only the measured acetate concentration (20 points per cycle). From interpolating the single cycle acetate data to multiple cycles, we estimate that a practical "optimal" identifiability could be achieved after two cycles for the acetate parameters, and three cycles for the ethanol parameters. The parameters found performed well in the short term, and represented the pulses of acetate and ethanol (within 4 days of the winery-fed cycles) very well. The main discrepancy was poor prediction of pH dynamics, which could be due to an unidentified buffer with an overall influence the same as a weak base (possibly CaCO3). Based on this work, ASBR systems are effective for parameter

  5. Anaerobic sequencing batch reactors and its influencing factors: an overview.

    PubMed

    Akil, K; Jayanthi, S

    2012-04-01

    Anaerobic sequencing batch reactors (ASBR) operate in four cyclic steps: feed, reaction, settling and discharge. ASBRs allow typical biological anaerobic metabolism from substrate consumption to methane and carbon dioxide production. Microorganisms in an ASBR are exposed to variable substrate concentrations over the duration of the cycle, resulting in high rates of substrate conversion and efficient biomass flocculation and settling. High substrate concentrations at the beginning of a cycle result in high metabolic activity and substrate removal. Low substrate concentrations towards the end of the cycle result in low biogas production and allow for good sludge settling. However, the cycles should be as frequent as possible while allowing for completion of each of the four stages. Operating by batches enables the solids residence time to be independent of the hydraulic retention time without recourse to a settling tank, since the reactor functions as a decanter whenever the stirring mechanism is turned off. This review presents an overview of the ASBR process and the various factors influencing its performance.

  6. Sequence of events during germination of putrefactive anaerobe 3679 spores.

    PubMed

    Uehara, M; Frank, H A

    1967-09-01

    The sequence of changes during germination of putrefactive anaerobe 3679h spores was studied under aerobic conditions in a solution containing l-alanine and sodium pyrophosphate. Evidence that specific changes occurred in two distinct regions of the spore is given by data on several criteria that were used to measure germination. During the initial stage of germination, the absorbancy decreased, dipicolinic acid was released, the spores lost their resistance to heat and toxic chemicals, and the spore periphery (cortex) darkened gradually under phase-contrast microscopy. The final stage of germination was characterized by changes in the central spore region (core), notably phase darkening of the spore center and stainability with mercurochrome, and by a slight additional absorbancy decrease.

  7. Evaluation of fructooligosaccharides separation using a fixed-bed column packed with activated charcoal.

    PubMed

    Kuhn, Raquel Cristine; Mazutti, Marcio A; Albertini, Lilian Buoro; Filho, Francisco Maugeri

    2014-05-25

    Recent studies have shown that the chromatographic separation of mixtures of saccharides may be improved by making use of activated charcoal, a promising low cost material for the separation of sugars, including fructooligosaccharides. In this work, the development of a methodology to separate fructooligosaccharides from glucose, fructose and sucrose, using a fixed bed column packed with activated charcoal is proposed. The influence of temperature, eluant concentration and step gradients were evaluated to increase the separation efficiency and fructooligosaccharide purity. The final degree of fructooligosaccharide purification and separation efficiency were about 94% and 3.03 respectively, using ethanol gradient concentration ranging from 3.5% to 15% (v/v) at 40°C. The fixed bed column packed with the activated charcoal was shown to be a promising alternative for sugar separation, mainly those rich in fructooligosaccharides, leading to solutions of acceptable degrees of purification.

  8. Fixed-bed gasification research using US coals. Volume 9. Gasification of Elkhorn bituminous coal

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-05-01

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) group. This report is the ninth volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This specific report describes the gasification of Elkhorn bituminous coal. The period of gasificastion test was September 13 to October 12, 1983. 9 refs., 24 figs., 35 tabs.

  9. Fixed-bed gasification research using US coals. Volume 7. Gasification of Piney Tipple bituminous coal

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-05-01

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report is the seventh volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This specific report describes the gasification of Piney Tipple bituminous coal. The period of the gasification test was July 18-24, 1983. 6 refs., 20 figs., 17 tabs.

  10. Fixed-bed gasification research using US coals. Volume 5. Gasification of Stahlman Stoker bituminous coal

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-03-31

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report is the fifth volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This specific report describes the gasification of Stahlman Stoker bituminous coal from Clarion County, PA. The period of the gasification test was April 30 to May 4, 1983. 4 refs., 16 figs., 10 tabs.

  11. Ex situ transmission electron microscopy: a fixed-bed reactor approach.

    PubMed

    Kliewer, Chris E; Kiss, Gabor; Demartin, Gregory J

    2006-04-01

    A fixed-bed reactor has been designed and constructed for ex situ transmission electron microscopy (TEM) studies of heterogeneous catalysts. The ex situ facility exposes a fully prepared TEM sample on a grid to actual process conditions (e.g., temperature, pressure, gas composition, etc.) by placing the grid at the exit section of a conventional fixed-bed reactor. A unique reactor design allows grid transfer into the electron microscope and back into the reactor again under a controlled (inert) environment, thus allowing time-resolved monitoring of catalyst morphology changes under realistic, well-controlled conditions. This facility stands completely independent of the TEM. Thus, no special TEM modifications are required and long-term ex situ studies do not impact microscope utilization. The utility of the facility is demonstrated via the oxidation of intermediate size ( approximately 20- approximately 80 nm) supported copper particles.

  12. Fixed-bed gasification research using US coals. Volume 19. Executive summary

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Liu, B.Y.H.; Pui, D.; Kittelson, D.

    1985-12-01

    A single-staged, fixed-bed, Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort under the Mining and Industrial Fuel Gas Group (MIFGA). This report is the nineteenth volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This volume briefly summarizes the results of eighteen different gasification tests in which fourteen different fuels were gasified from May 1982 to August 1985. The design gasification performance of all coals evaluated are summarized. In addition, summary design and economic data for industrial coal gasification systems are presented. 28 refs., 2 figs., 22 tabs.

  13. Effect of ash content on the combustion process of simulated MSW in the fixed bed.

    PubMed

    Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

    2016-02-01

    This paper experimentally and numerically investigates the effects of ash content on the combustion process of simulated Municipal Solid Waste (MSW). A fixed-bed experimental reactor was utilized to reveal the combustion characteristics. Temperature distributions, ignition front velocity, and the characteristics of gas species' release were measured and simulated during the combustion process. In the present work, the two-dimensional unsteady mathematical heterogeneous model was developed to simulate the combustion process in the bed, including the process rate model as well as NOx production model. The simulation results in the bed are accordant with the experimental results. The results show that as ash content increases, the lower burning rate of fuel results in char particles leaving the grate without being fully burned, causing a loss of combustible material in the MSW in a fixed bed and therefore reducing the combustion efficiency and increasing the burning time of the MSW. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Fixed-bed gasification research using US coals. Volume 4. Gasification of Leucite Hills subbituminous coal

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-03-31

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report is the fourth volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This specific report describes the gasification of Leucite Hills subbituminous coal from Sweetwater County, Wyoming. The period of the gasification test was April 11-30, 1983. 4 refs., 23 figs., 27 tabs.

  15. Kinetic studies of elemental mercury adsorption in activated carbon fixed bed reactor.

    PubMed

    Skodras, G; Diamantopoulou, Ir; Pantoleontos, G; Sakellaropoulos, G P

    2008-10-01

    Activated carbons are suitable materials for Hg(0) adsorption in fixed bed operation or in injection process. The fixed bed tests provide good indication of activated carbons effectiveness and service lives, which depend on the rates of Hg(0) adsorption. In order to correlate fixed bed properties and operation conditions, with their adsorptive capacity and saturation time, Hg(0) adsorption tests were realized in a bench-scale unit, consisted of F400 activated carbon fixed bed reactor. Hg(0) adsorption tests were conducted at 50 degrees C, under 0.1 and 0.35 ng/cm(3) Hg(0) initial concentrations and with carbon particle sizes ranging between 75-106 and 150-250 microm. Based on the experimental breakthrough data, kinetic studies were performed to investigate the mechanism of adsorption and the rate controlling steps. Kinetic models evaluated include the Fick's intraparticle diffusion equation, the pseudo-first order model, the pseudo-second order model and Elovich kinetic equation. The obtained experimental results revealed that the increase in particle size resulted in significant decrease of breakthrough time and mercury adsorptive capacity, due to the enhanced internal diffusion limitations and smaller external mass transfer coefficients. Additionally, higher initial mercury concentrations resulted in increased breakthrough time and mercury uptake. From the kinetic studies results it was observed that all the examined models describes efficiently Hg(0) breakthrough curves, from breakpoint up to equilibrium time. The most accurate prediction of the experimental data was achieved by second order model, indicating that the chemisorption rate seems to be the controlling step in the procedure. However, the successful attempt to describe mercury uptake with Fick's diffusion model and the first order kinetic model, reveals that the adsorption mechanism studied was complex and followed both surface adsorption and particle diffusion.

  16. Transition from creeping via viscous-inertial to turbulent flow in fixed beds.

    PubMed

    Hlushkou, Dzmitry; Tallarek, Ulrich

    2006-09-08

    This review is concerned with the analysis of flow regimes in porous media, in particular, in fixed beds of spherical particles used as reactors in engineering applications, or as separation units in liquid chromatography. A transition from creeping via viscous-inertial to turbulent flow is discussed based on macro-scale transport behaviour with respect to the pressure drop-flow rate dependence, in particular, the deviation from Darcy's law, as well as direct microscopic data which reflect concomitant changes in the pore-level hydrodynamics. In contrast to the flow behaviour in straight pipes, the transition from laminar to turbulent flow in fixed particulate beds is not sharp, but proceeds gradually through a viscous-inertial flow regime. The onset of this steady, nonlinear regime and increasing role of inertial forces is macroscopically manifested in the failure of Darcy's law to describe flow through fixed beds at higher Reynolds numbers. While the physical reasons for this failure still are not completely understood, it is not caused by turbulence which occurs at Reynolds numbers about two orders of magnitude above those for which a deviation from Darcy's law is observed. Microscopic analysis shows that this steady, nonlinear flow regime is characterized by the development of an inertial core in the pore-level profile, i.e., at increasing Reynolds number velocity profiles in individual pores become flatter towards the center of the pores, while the velocity gradient increases close to the solid-liquid interface. Further, regions with local backflow and stationary eddies are demonstrated for the laminar flow regime in fixed beds. The onset of local fluctuations (end of laminar regime) is observed at superficial Reynolds numbers on the order of 100. Complementary analysis of hydrodynamic dispersion suggests that this unsteady flow accelerates lateral equilibration between different velocities in fixed beds which, in turn, reduces spreading in the longitudial

  17. Alkylation of benzene using batch and continuous fixed-bed reactors.

    SciTech Connect

    Nenoff, Tina Maria; Buelna Quijada, Genoveva

    2004-09-01

    Alkylation reactions of benzene with propylene using heterogeneous catalysts H{sup +}-{beta} zeolite, MCM-22, and ZSM-5 were studied for their affinity for cumene production. This work focused on the gas-phase reaction using different crystalline catalysts at several temperatures and amounts of reactants using both batch and continuous fixed-bed reactors. The properties of baseline commercial H{sup +}-{beta} catalysts versus versions modified with Ga, La, and Pt were studied. Quantitative analysis of product mixture was performed by gas chromatography. For the batch reactor, {beta}-zeolite produced the highest cumene yield and selectivity of 72% and 92%, respectively, at 225 C. At this temperature, a benzene:propylene dilution of 7:1 molar ratio was the optimum. For the continuous system, cumene production is favored at lower space velocities, higher benzene-to-propylene ratio, and temperatures close to 225 C. Ga modification of the H{sup +}-{beta} zeolite significantly enhanced cumene yield in the continuous fixed-bed reactor at 225 C, from 27% of the unmodified {beta}-zeolite to 36% for the Ga-modified one. The life span of modified {beta}-catalysts was studied in the fixed-bed reactor for the first eight hours of reaction.

  18. Anaerobic

    MedlinePlus

    ... more prolonged exercise like walking or jogging. Anaerobic reactions are faster. We need them during shorter, more intense activities like sprinting. Anaerobic exercise leads to a buildup of lactic acid in our tissues. We need oxygen to remove ...

  19. Long-term starvation and subsequent recovery of nitrifiers in aerated submerged fixed-bed biofilm reactors.

    PubMed

    Elawwad, Abdelsalam; Sandner, Hendrik; Kappelmeyer, Uwe; Koeser, Heinz

    2013-01-01

    The effectiveness of three operational strategies for maintaining nitrifiers in bench-scale, aerated, submerged fixed-bed biofilm reactors (SFBBRs) during long-term starvation at 20 degrees C were evaluated. The operational strategies were characterized by the resulting oxidation-reduction potential (ORP) in the SFBBRs. The activity rates of the nitrifiers were measured and the activity decay was expressed by half-life times. It was found that anoxic and alternating anoxic/aerobic conditions were the best ways to preserve ammonia-oxidizing bacteria (AOB) during long starvation periods and resulted in half-life times of up to 34 and 28 days, respectively. Extended anaerobic conditions caused the half-life for AOB to decrease to 21 days. In comparison, the activity decay of nitrite-oxidizing bacteria (NOB) tended to be slightly faster. The activity of AOB biofilms that were kept for 97 days under anoxic conditions could be completely recovered in less than one week, while over 4 weeks was needed for AOB kept under anaerobic conditions. NOB were more sensitive to starvation and required longer recovery periods than AOB. For complete recovery, NOB needed approximately 7 weeks, regardless of the starvation conditions applied. Using the fluorescence in situ hybridization (FISH) technique, Nitrospira was detected as the dominant NOB genus. Among the AOB, the terminal restriction fragment length polymorphism (TRFLP) technique showed that during starvation and recovery periods, the relative frequency of species shifted to Nitrosomonas europaea/eutropha, regardless of the starvation condition. The consequences of these findings for the operation of SFBBRs under low-load and starvation conditions are discussed.

  20. Treatment of winery wastewater by an anaerobic sequencing batch reactor.

    PubMed

    Ruíz, C; Torrijos, M; Sousbie, P; Lebrato Martínez, J; Moletta, R; Delgenès, J P

    2002-01-01

    Treatment of winery wastewater was investigated using an anaerobic sequencing batch reactor (ASBR). Biogas production rate was monitored and permitted the automation of the bioreactor by a simple control system. The reactor was operated at an organic loading rate (ORL) around 8.6 gCOD/L.d with soluble chemical oxygen demand (COD) removal efficiency greater than 98%, hydraulic retention time (HRT) of 2.2 d and a specific organic loading rate (SOLR) of 0.96 gCOD/gVSS.d. The kinetics of COD and VFA removal were investigated for winery wastewater and for simple compounds such as ethanol, which is a major component of winery effluent, and acetate, which is the main volatile fatty acid (VFA) produced. The comparison of the profiles obtained with the 3 substrates shows that, overall, the acidification of the organic matter and the methanisation of the VFA follow zero order reactions, in the operating conditions of our study. The effect on the gas production rate resulted in two level periods separated by a sharp break when the acidification stage was finished and only the breaking down of the VFA continued.

  1. Complete Genome Sequence of Finegoldia magna, an Anaerobic Opportunistic Pathogen

    PubMed Central

    Goto, Takatsugu; Yamashita, Atsushi; Hirakawa, Hideki; Matsutani, Minenosuke; Todo, Kozo; Ohshima, Kenshiro; Toh, Hidehiro; Miyamoto, Kazuaki; Kuhara, Satoru; Hattori, Masahira; Shimizu, Tohru; Akimoto, Shigeru

    2008-01-01

    Finegoldia magna (formerly Peptostreptococcus magnus), a member of the Gram-positive anaerobic cocci (GPAC), is a commensal bacterium colonizing human skin and mucous membranes. Moreover, it is also recognized as an opportunistic pathogen responsible for various infectious diseases. Here, we report the complete genome sequence of F. magna ATCC 29328. The genome consists of a 1 797 577 bp circular chromosome and an 189 163 bp plasmid (pPEP1). The metabolic maps constructed based on the genome information confirmed that most F. magna strains cannot ferment most sugars, except fructose, and have various aminopeptidase activities. Three homologs of albumin-binding protein, a known virulence factor useful for antiphagocytosis, are encoded on the chromosome, and one albumin-binding protein homolog is encoded on the plasmid. A unique feature of the genome is that F. magna encodes many sortase genes, of which substrates may be involved in bacterial pathogenesis, such as antiphagocytosis and adherence to the host cell. The plasmid pPEP1 encodes seven sortase and seven substrate genes, whereas the chromosome encodes four sortase and 19 substrate genes. These plasmid-encoded sortases may play important roles in the pathogenesis of F. magna by enriching the variety of cell wall anchored surface proteins. PMID:18263572

  2. Treatment of brewery slurry in thermophilic anaerobic sequencing batch reactor.

    PubMed

    Zupancic, Gregor D; Straziscar, Matej; Ros, Milenko

    2007-10-01

    Treatment of brewery slurry in a thermophilic anaerobic sequencing batch reactor (ASBR) was studied using conventional fully mixed semi-continuous digestion as a control. The process phases were adapted to fit the brewery slurry discharge schedule. ASBR experiments were conducted under different organic loading rates (OLR) from 3.23 to 8.57 kg of COD/m(3)day of reactor and control was conducted with OLR of 3.0 kg of COD/m(3)day. The ASBR COD degradation efficiency was from 79.6% to 88.9%, control experiment efficiency was 65%. ASBR VSS removal efficiency was from 78.5% to 90.5%, control experiment efficiency was 54%. The ASBR methane production yield was from 371 to 418 L/kg COD inserted, control experiment methane yield was 248 L/kg COD inserted. The ASBR process was superior to conventional fully mixed digestion, and is fully adaptable to brewery slurry discharge, needs no additional collection and settling pools and experiences no solids settling problems.

  3. Large-scale Clinical-grade Retroviral Vector Production in a Fixed-Bed Bioreactor

    PubMed Central

    Wang, Xiuyan; Olszewska, Malgorzata; Qu, Jinrong; Wasielewska, Teresa; Bartido, Shirley; Hermetet, Gregory; Sadelain, Michel

    2015-01-01

    The successful genetic engineering of patient T cells with γ-retroviral vectors expressing chimeric antigen receptors or T-cell receptors for phase II clinical trials and beyond requires the large-scale manufacture of high-titer vector stocks. The production of retroviral vectors from stable packaging cell lines using roller bottles or 10- to 40-layer cell factories is limited by a narrow harvest window, labor intensity, open-system operations, and the requirement for significant incubator space. To circumvent these shortcomings, we optimized the production of vector stocks in a disposable fixed-bed bioreactor using good manufacturing practice–grade packaging cell lines. High-titer vector stocks were harvested over 10 days, representing a much broader harvest window than the 3-day harvest afforded by cell factories. For PG13 and 293Vec packaging cells, the average vector titer and the vector stocks’ yield in the bioreactor were higher by 3.2- to 7.3-fold, and 5.6- to 13.1-fold, respectively, than those obtained in cell factories. The vector production was 10.4 and 18.6 times more efficient than in cell factories for PG13 and 293Vec cells, respectively. Furthermore, the vectors produced from the fixed-bed bioreactors passed the release test assays for clinical applications. Therefore, a single vector lot derived from 293Vec is suitable to transduce up to 500 patients cell doses in the context of large clinical trials using chimeric antigen receptors or T-cell receptors. These findings demonstrate for the first time that a robust fixed-bed bioreactor process can be used to produce γ-retroviral vector stocks scalable up to the commercialization phase. PMID:25751502

  4. Large-scale clinical-grade retroviral vector production in a fixed-bed bioreactor.

    PubMed

    Wang, Xiuyan; Olszewska, Malgorzata; Qu, Jinrong; Wasielewska, Teresa; Bartido, Shirley; Hermetet, Gregory; Sadelain, Michel; Rivière, Isabelle

    2015-04-01

    The successful genetic engineering of patient T cells with γ-retroviral vectors expressing chimeric antigen receptors or T-cell receptors for phase II clinical trials and beyond requires the large-scale manufacture of high-titer vector stocks. The production of retroviral vectors from stable packaging cell lines using roller bottles or 10- to 40-layer cell factories is limited by a narrow harvest window, labor intensity, open-system operations, and the requirement for significant incubator space. To circumvent these shortcomings, we optimized the production of vector stocks in a disposable fixed-bed bioreactor using good manufacturing practice-grade packaging cell lines. High-titer vector stocks were harvested over 10 days, representing a much broader harvest window than the 3-day harvest afforded by cell factories. For PG13 and 293Vec packaging cells, the average vector titer and the vector stocks' yield in the bioreactor were higher by 3.2- to 7.3-fold, and 5.6- to 13.1-fold, respectively, than those obtained in cell factories. The vector production was 10.4 and 18.6 times more efficient than in cell factories for PG13 and 293Vec cells, respectively. Furthermore, the vectors produced from the fixed-bed bioreactors passed the release test assays for clinical applications. Therefore, a single vector lot derived from 293Vec is suitable to transduce up to 500 patients cell doses in the context of large clinical trials using chimeric antigen receptors or T-cell receptors. These findings demonstrate for the first time that a robust fixed-bed bioreactor process can be used to produce γ-retroviral vector stocks scalable up to the commercialization phase.

  5. Fixed-bed adsorption study of methylene blue onto pyrolytic tire char

    NASA Astrophysics Data System (ADS)

    Makrigianni, Vassiliki; Giannakas, Aris; Papadaki, Maria; Albanis, Triantafyllos; Konstantinou, Ioannis

    2016-04-01

    In this work, the adsorption efficiency of acid treated pyrolytic tire char to cationic methylene blue (MB) dye adsorption from aqueous solutions was investigated by fixed-bed adsorption column experiments. The effects of the initial dye concentration (10 - 40 mg L-1) and feed flow rate (50 - 150 mL min -1) with a fixed bed height (15 cm) were studied in order to determine the breakthrough characteristics of the adsorption system. The Adams-Bohart, Yoon-Nelson and Thomas model were applied to the adsorption of MB onto char at different operational conditions to predict the breakthrough curves and to determine the characteristic parameters of the column. The results showed that the maximum adsorbed quantities decreased with increasing flow rate and increased with increasing initial MB concentration. Breakthrough time and exhaustion time increased with decreasing inlet dye concentration and flow rate. In contrast with Adams-Bohart model, Yoon-Nelson model followed by Thomas model were found more suitable to describe the fixed-bed adsorption of methylene blue by char. The correlation coefficient values R2 for both models at different operating conditions are higher than 0.9 and the low average relative error values provided very good fittings of experimental data at different operating conditions. Higher adsorption capacity of 3.85 mg g -1 was obtained at 15 cm of adsorbent bed height, flow rate of 100 mL min -1and initial MB concentration of 40 mg L-1. Although that activated carbons exhibited higher adsorption capacities in the literature, acid-treated pyrolytic tire char was found to be considerably efficient adsorbent for the removal of MB dye column taking into account the advantages of the simpler production process compared to activated carbons, as well as, the availability of waste tire feedstock and concurrent waste tire management.

  6. Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed-Bed Reactor

    SciTech Connect

    Buitrago, Paula A.; Morrill, Mike; Lighty, JoAnn S.; Silcox, Geoffrey D.

    2009-06-15

    This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150°C. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and

  7. Fixed-bed gasifier and cleanup system engineering summary report through Test Run No. 100

    SciTech Connect

    Pater, K. Jr.; Headley, L.; Kovach, J.; Stopek, D.

    1984-06-01

    The state-of-the-art of high-pressure, fixed-bed gasification has been advanced by the many refinements developed over the last 5 years. A novel full-flow gas cleanup system has been installed and tested to clean coal-derived gases. This report summarizes the results of tests conducted on the gasifier and cleanup system from its inception through 1982. Selected process summary data are presented along with results from complementary programs in the areas of environmental research, process simulation, analytical methods development, and component testing. 20 references, 32 figures, 42 tables.

  8. Two-stage fixed-bed gasifier with selectable middle gas off-take point

    DOEpatents

    Strickland, Larry D.; Bissett, Larry A.

    1992-01-01

    A two-stage fixed bed coal gasifier wherein an annular region is in registry with a gasification zone underlying a devolatilization zone for extracting a side stream of high temperature substantially tar-free gas from the gasifier. A vertically displaceable skirt means is positioned within the gasifier to define the lower portion of the annular region so that vertical displacement of the skirt means positions the inlet into the annular region in a selected location within or in close proximity to the gasification zone for providing a positive control over the composition of the side stream gas.

  9. Use of natural clinoptilolite for the removal of lead, copper and zinc in fixed bed column.

    PubMed

    Stylianou, Marinos A; Hadjiconstantinou, Michalis P; Inglezakis, Vasilis J; Moustakas, Konstantinos G; Loizidou, Maria D

    2007-05-08

    This work deals with the removal of lead, copper and zinc from aqueous solutions by using natural zeolite (clinoptilolite). Fixed bed experiments were performed, using three different volumetric flow rates of 5, 7 and 10bed volume/h, under a total normality of 0.01N, at initial pH of 4 and ambient temperature (25 degrees C). The removal efficiency increased when decreasing the flow rate and the following selectivity series was found: Pb(2+)>Zn(2+)> or =Cu(2+). Conductivity measurements showed that lead removal follows mainly ion exchange mechanism, while copper and zinc removal follows ion exchange and sorption mechanism as well.

  10. Liquid flow residence time in a fibrous fixed bed reactor with recycle.

    PubMed

    Martinov, Martin; Hadjiev, Dimiter; Vlaev, Serafim

    2010-02-01

    Waste removal efficiency of gas-liquid biofilter reactors for waste water treatment depends on its flow regime and residence time distribution (RTD) as key parameters of bio-reactor performance. The present study reports RTD regime in a fibrous fixed bed biofilm reactor related to a fluid velocity range appropriate for biofilm operation. The data from tracer experiments are correlated in terms of the one-parameter "tanks-in-series" model. The aerated fibrous bed reactor RTD function is found to be dependent on net liquid and gas phase superficial velocity U(L) and U(G). Liquid internal recirculation exhibited small effect comparable with the effect of net liquid flow. A power law relationship relating the number of perfectly mixed cells with liquid and gas superficial velocity is elaborated. Assuming similarity of the prototype and real vessels' flow fields, the equation as well as its corresponding range of fluid velocity can be used for bio-reactor design and scale-up. Comparison over the model parameters obtained in fixed bed bubble columns at low fluid velocity shows the results of this study to be comparable with previous data of mesh wire packing.

  11. Remediation of trichloroethylene by bio-precipitated and encapsulated palladium nanoparticles in a fixed bed reactor.

    PubMed

    Hennebel, Tom; Verhagen, Pieter; Simoen, Henri; De Gusseme, Bart; Vlaeminck, Siegfried E; Boon, Nico; Verstraete, Willy

    2009-08-01

    Trichloroethylene is a toxic and recalcitrant groundwater pollutant. Palladium nanoparticles bio-precipitated on Shewanella oneidensis were encapsulated in polyurethane, polyacrylamide, alginate, silica or coated on zeolites. The reactivity of these bio-Pd beads and zeolites was tested in batch experiments and trichloroethylene dechlorination followed first order reaction kinetics. The calculated k-values of the encapsulated catalysts were a factor of six lower compared to non-encapsulated bio-Pd. Bio-Pd, used as a catalyst, was able to dechlorinate 100 mgL(-1) trichloroethylene within a time period of 1h. The main reaction product was ethane; yet small levels of chlorinated intermediates were detected. Subsequently polyurethane cubes empowered with bio-Pd were implemented in a fixed bed reactor for the treatment of water containing trichloroethylene. The influent recycle configuration resulted in a cumulative removal of 98% after 22 h. The same reactor in a flow through configuration achieved removal rates up to 1059 mg trichloroethylene g Pd(-1)d(-1). This work showed that fixed bed reactors with bio-Pd polyurethane cubes can be instrumental for remediation of water contaminated with trichloroethylene.

  12. Fixed bed column study for Cd(II) removal from wastewater using treated rice husk.

    PubMed

    Kumar, Upendra; Bandyopadhyay, Manas

    2006-02-28

    A fixed bed of sodium carbonate treated rice husk was used for the removal of Cd(II) from water environment. The material as adopted was found to be an efficient media for the removal of Cd(II) in continuous mode using fixed bed column. The column having a diameter of 2 cm, with different bed depths such as 10, 20 and 30 cm could treat 2.96, 5.70 and 8.55 l of Cd(II) bearing wastewater with Cd(II) concentration 10 mg/l and flow rate 9.5 ml/min. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, etc. was calculated. Effect of flow rate and initial concentration was studied. Theoretical breakthrough curve was drawn from the batch isotherm data and it was compared with experimental breakthrough curve. An amount of 0.01 mol/l HCl solution was used for desorption of adsorption column. Column regeneration and reuse studies were conducted for two cycles of adsorption-desorption.

  13. Co-pyrolysis characteristics of sawdust and coal blend in TGA and a fixed bed reactor.

    PubMed

    Park, Dong Kyoo; Kim, Sang Done; Lee, See Hoon; Lee, Jae Goo

    2010-08-01

    Co-pyrolysis characteristics of sawdust and coal blend were determined in TGA and a fixed bed reactor. The yield and conversion of co-pyrolysis of sawdust and coal blend based on volatile matters are higher than those of the sum of sawdust and coal individually. Form TGA experiments, weight loss rate of sawdust and coal blend increases above 400 degrees C and additional weight loss was observed at 700 degrees C. In a fixed bed at isothermal condition, the synergy to produce more volatiles is appeared at 500-700 degrees C, and the maximum synergy exhibits with a sawdust blending ratio of 0.6 at 600 degrees C. The gas product yields remarkably increase at lower temperature range by reducing tar yield. The CO yield increases up to 26% at 400 degrees C and CH(4) yield increases up to 62% at 600 degrees C compared with the calculated value from the additive model. (c) 2010 Elsevier Ltd. All rights reserved.

  14. High temperature CO2 capture using calcium oxide sorbent in a fixed-bed reactor.

    PubMed

    Dou, Binlin; Song, Yongchen; Liu, Yingguang; Feng, Cong

    2010-11-15

    The gas-solid reaction and breakthrough curve of CO(2) capture using calcium oxide sorbent at high temperature in a fixed-bed reactor are of great importance, and being influenced by a number of factors makes the characterization and prediction of these a difficult problem. In this study, the operating parameters on reaction between solid sorbent and CO(2) gas at high temperature were investigated. The results of the breakthrough curves showed that calcium oxide sorbent in the fixed-bed reactor was capable of reducing the CO(2) level to near zero level with the steam of 10 vol%, and the sorbent in CaO mixed with MgO of 40 wt% had extremely low capacity for CO(2) capture at 550°C. Calcium oxide sorbent after reaction can be easily regenerated at 900°C by pure N(2) flow. The experimental data were analyzed by shrinking core model, and the results showed reaction rates of both fresh and regeneration sorbents with CO(2) were controlled by a combination of the surface chemical reaction and diffusion of product layer.

  15. Racemization of undesired enantiomers: Immobilization of mandelate racemase and application in a fixed bed reactor.

    PubMed

    Wrzosek, Katarzyna; Rivera, Mariel A García; Bettenbrock, Katja; Seidel-Morgenstern, Andreas

    2016-03-01

    Production of optically pure products can be based on simple unselective synthesis of racemic mixtures combined with a subsequent separation of the enantiomers; however, this approach suffers from a 50% yield limitation which can be overcome by racemization of the undesired enantiomer and recycling. Application of biocatalyst for the racemization steps offers an attractive option for high-yield manufacturing of commercially valuable compounds. Our work focuses on exploiting the potential of racemization with immobilized mandelate racemase. Immobilization of crude mandelate racemase via covalent attachment was optimized for two supports: Eupergit(®) CM and CNBr-activated Sepharose 4 Fast Flow. To allow coupling of enzymatic reaction with enantioselective chromatography, a mobile phase composition compatible with both processes was used in enzymatic reactor. Kinetic parameters obtained analyzing experiments carried out in a batch reactor could be successfully used to predict fixed-bed reactor performance. The applicability of the immobilized enzyme and the determined kinetic parameters were validated in transient experiments recording responses to pulse injections of R-mandelic acid. The approach investigated can be used for futher design and optimization of high yield combined resolution processes. The characterized fixed-bed enzymatic reactor can be integrated e.g. with chromatographic single- or multicolumn steps in various configurations.

  16. Partial oxidation of sewage sludge briquettes in a updraft fixed bed.

    PubMed

    Kim, Minsu; Lee, Yongwoon; Park, Jinje; Ryu, Chankook; Ohm, Tae-In

    2016-03-01

    The fixed bed reaction of sewage sludge briquettes was investigated to evaluate the potential applications to gasification, combustion, or production of biochar as soil ameliorator. The reaction had two distinctive stages: ignition propagation and char oxidation. The ignition front of the sludge briquettes propagated at a lower speed, which significantly increased the stoichiometric ratio of overall combustion reaction and peak temperatures. The ignition front also had irregular shapes due to the channeling effects. During the char oxidation stage, the sludge ash agglomerated because of the slow reaction rate and increased CO2 formation. Because of low energy content in the product gas, the large briquettes were not favorable for syngas production. In addition, the low burning rates and ash agglomeration could cause problems in the operation of a grate-type furnace for combustion. However, the char accumulated above the ignition front had similar properties with that from pyrolysis under inert atmosphere. Therefore, the fixed bed reaction under partial oxidation conditions can be applied to produce biochar as soil ameliorator from the sludge briquettes without external heat supply. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Performance and microbial community of carbon nanotube fixed-bed microbial fuel cell continuously fed with hydrothermal liquefied cornstalk biomass.

    PubMed

    Liu, Zhidan; He, Yanhong; Shen, Ruixia; Zhu, Zhangbing; Xing, Xin-Hui; Li, Baoming; Zhang, Yuanhui

    2015-06-01

    Hydrothermal liquefaction (HTL) is a green technology for biomass pretreatment with the omission of hazardous chemicals. This study reports a novel integration of HTL and carbon nanotubes (CNTs) fixed-bed microbial fuel cell (FBMFC) for continuous electricity generation from cornstalk biomass. Two FBMFCs in parallel achieved similar performance fed with cornstalk hydrolysate at different organic loading rates (OLRs) (0.82-8.16g/L/d). About 80% of Chemical oxygen demand (COD) and Total organic carbon (TOC) was removed from low-Biochemical oxygen demand (BOD)/COD (0.16) cornstalk hydrolysate at 8.16g/L/d, whereas a maximum power density (680mW/m(3)) was obtained at 2.41g/L/d, and a smallest internal resistance (Rin) (28Ω) at 3.01g/L/d. Illumina MiSeq sequencing reveals the diverse microbial structure induced by the complex composition of cornstalk hydrolysate. Distinguished from Proteobacteria, which a number of exoelectrogens belong to, the identified dominant genus Rhizobium in FBMFC was closely related to degradation of cellulosic biomass.

  18. Complete genome sequence of the anaerobic, halophilic alkalithermophile Natranaerobius thermophilus JW/NM-WN-LF.

    PubMed

    Zhao, Baisuo; Mesbah, Noha M; Dalin, Eileen; Goodwin, Lynne; Nolan, Matt; Pitluck, Sam; Chertkov, Olga; Brettin, Thomas S; Han, James; Larimer, Frank W; Land, Miriam L; Hauser, Loren; Kyrpides, Nikolaos; Wiegel, Juergen

    2011-08-01

    The genome of the anaerobic halophilic alkalithermophile Natranaerobius thermophilus consists of one 3,165,557-bp chromosome and two plasmids (17,207 bp and 8,689 bp). The present study is the first to report the completely sequenced genome of an anaerobic polyextremophile and genes associated with roles in regulation of intracellular osmotic pressure, pH homeostasis, and growth at elevated temperatures.

  19. Adsorption of p-nitrophenol on activated carbon fixed-bed.

    PubMed

    Sabio, E; Zamora, F; Gañan, J; González-García, C M; González, J F

    2006-09-01

    Carbon fixed-beds are usually used to remove organic contaminants. Adsorption in a carbon filter is a dynamic, non-steady process which is not yet completely understood. The objective of this paper is to establish a methodology to simplify the study of this process based on the wave theory, rapid small-scale column test and experimental design/surface response analysis. The constant pattern wave hypothesis was confirmed by the experimental data. The influence of the inlet concentration of p-nitrophenol and the flow rate on dynamic adsorption was studied at 20 degrees C following a central composite design using a second-order model. Both parameters have an important influence on the response variables studied. The methodology used is a useful tool for studying the dynamic process and shows interactions that are difficult to verify by the classical step-by-step method.

  20. Characterization and fixed-bed testing of a nickel-based hot gas desulfurization sorbent

    SciTech Connect

    Gasper-Galvin, L.D.; Swisher, J.H.; Hammerbeck, K.

    1994-10-01

    The objective of this project was to (1) extend a preliminary investigation completed earlier on dispersed nickel sorbents by developing new processing methods, characterizing sorbent materials more extensively, and evaluating the materials in fixed bed reactor tests, and (2) to determine the feasibility of using dispersed nickel sorbents with reductive regeneration for hot gas desulfurization. One of the properties of nickel that is somewhat unique is that it forms a liquid sulfide at sufficiently high temperatures with high sulfur potentials or H{sub 2}S levels. A eutectic exists in the Ni-S phase diagram at 637 C and a composition of 33.4 wt% or 21.5 wt% S. Under controlled conditions, the formation of a liquid phase can be used to advantage in hot gas desulfurization. Sorbent preparation, the experimental unit, and experimental procedure are described. Results from the sorbent, 24Ni-7Cu-Al{sub 2}O{sub 3}, are given.

  1. Pyrolysis and combustion of oil palm stone and palm kernel cake in fixed-bed reactors.

    PubMed

    Razuan, R; Chen, Q; Zhang, X; Sharifi, V; Swithenbank, J

    2010-06-01

    The main objective of this research was to investigate the main characteristics of the thermo-chemical conversion of oil palm stone (OPS) and palm kernel cake (PKC). A series of combustion and pyrolysis tests were carried out in two fixed-bed reactors. The effects of heating rate at the temperature of 700 degrees C on the yields and properties of the pyrolysis products were investigated. The results from the combustion experiments showed that the burning rates increased with an increase in the air flow rate. In addition, the FLIC code was used to simulate the combustion of the oil palm stone to investigate the effect of primary air flow on the combustion process. The FLIC modelling results were in good agreement with the experimental data in terms of predicting the temperature profiles along the bed height and the composition of the flue gases.

  2. Removal of hydrogen sulfide using palygorskite in a fixed bed adsorber.

    PubMed

    Higuchi, T; Zhang, Q; Sekine, M; Imai, T; Yamamoto, K

    2012-01-01

    This work describes the use of a novel palygorskite, a type of magnesium aluminium silicate clay possessing a high specific surface area and pore surface activity, as a low cost and highly efficient adsorbent for hydrogen sulfide (H(2)S) removal. Adsorption of H(2)S on palygorskite pretreated with acid or base was investigated in a fixed bed adsorber. The samples after base pretreatment had better dynamic adsorption performances than raw material and samples pretreated with acid. The H(2)S adsorption capacity decreased with an increase in inlet H(2)S concentration. This can be interpreted by the fact that H(2)S adsorption on the surface of palygorskite is chemisorption. The adsorption capacity increased from 25 to 50 °C, then decreased from 50 to 100 °C, which indicates that chemisorption took place and its better reaction temperature was around 50 °C.

  3. Bioremoval of heavy metals from industrial effluent by fixed-bed column of red macroalgae.

    PubMed

    Ibrahim, Wael M; Mutawie, Hawazin H

    2013-02-01

    Three different species of nonliving red algal biomass Laurancia obtusa, Geldiella acerosa and Hypnea sp. were used to build three types of fixed-bed column for the removal of toxic heavy metal ions such as Cu(2+), Zn(2+), Mn(2+) and Ni(2+) from industrial effluent. In general, the highest efficiency of metal ion bioremoval was recorded for algal column of L. obtusa followed by G. acerosa and the lowest one was recorded for Hypnea sp., with mean removal values of 94%, 85% and 71%, respectively. The obtained results showed that biological treatments of industrial effluents with these algal columns, using standard algal biotest, Pseudokirchneriella subcapitata, were capable of reducing effluent toxicities from 75% to 15%, respectively. Red algal column may be considered as an inexpensive and efficient alternative treatment for conventional removal technology, for sequestering heavy metal ions from industrial effluents.

  4. A batch and fixed bed column study for fluorescein removal using chitosan modified by epichlorohydrin.

    PubMed

    Silva, P M O; Francisco, J E; Cajé, J C M; Cassella, R J; Pacheco, W F

    2017-09-29

    This study evaluates the feasibility of commercial chitosan (CQ) and modified chitosan (MQ) by epichlorohydrin to be used as a solid phase to remove fluorescein (FSC) from aqueous solutions by two different approaches: in batch and on a fixed column bed. For the batch study, all parameters that influence sorption capacity were evaluated, such as: pH, mass, ionic strength, temperature and time of contact. In the optimized condition, 75% removal was obtained for FSC using CQ, while the modification allowed an increase up to 99%, as well as an increase in the stability of the polymer. In the fixed column bed study, the influence of all the parameters was evaluated through breakthrough curves, and the thermodynamics parameters of each approach were obtained. The results of these studies demonstrate that the modification with epichlorohydrin enhanced the sorptive properties (from 35% to 95% in fixed bed experiments) and the polymer stability (making it insoluble), making it suitable to be used in wastewater treatment.

  5. Nitrifying microorganisms in fixed-bed biofilm reactors fed with different nitrite and ammonia concentrations.

    PubMed

    ter Haseborg, Eike; Zamora, Talia Mateu; Fröhlich, Jörn; Frimmel, Fritz H

    2010-03-01

    Nitrifying bacteria and archaea were fed in fixed-bed biofilm reactors with different nitrite and ammonia concentrations in synthetic and real wastewater. During high nitrite concentrations (rho(NO(2)(-))=5-10mg/L), an increase in the abundance of Nitrobacter species was detected with fluorescence in situ hybridization (FISH), while Nitrospira species disappeared to a large extent. During high ammonia concentrations (rho(NH(4)(+))=60-80 mg/L), a slight increase in ammonia-oxidizing bacteria was obtained, while the abundance of archaebacteria remained unchanged. Lab-scale reactors showed a similar nitrifying microbial population as reactors fed with real wastewater. However, increased abundances of Nitrospira species as observed in wastewater reactors and in the wastewater trickling filters could not be found in the laboratory reactors. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  6. Empirical correlations for axial dispersion coefficient and Peclet number in fixed-bed columns.

    PubMed

    Rastegar, Seyed Omid; Gu, Tingyue

    2017-03-24

    In this work, a new correlation for the axial dispersion coefficient was obtained using experimental data in the literature for axial dispersion in fixed-bed columns packed with particles. The Chung and Wen correlation, the De Ligny correlation are two popular empirical correlations. However, the former lacks the molecular diffusion term and the latter does not consider bed voidage. The new axial dispersion coefficient correlation in this work was based on additional experimental data in the literature by considering both molecular diffusion and bed voidage. It is more comprehensive and accurate. The Peclet number correlation from the new axial dispersion coefficient correlation on the average leads to 12% lower Peclet number values compared to the values from the Chung and Wen correlation, and in many cases much smaller than those from the De Ligny correlation. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Development of a Ventilation and Air-conditioning System using Fixed Bed Desiccant Units

    NASA Astrophysics Data System (ADS)

    Miyazaki, Takahiko; Akisawa, Atsushi; Ueda, Yuki; Shindoh, Shinji; Godo, Masazumi; Takatsuka, Takeshi

    The study investigated fixed bed desiccant units for ventilation and air-conditioning. The role of the system is the dehumidification of the outdoor fresh air to be supplied to an air-conditioned room. Hence, the latent heat load of the air-conditioner in the room can be mitigated. The system consisted of two pairs of a desiccant unit and a heat storage unit. The microwave irradiation to the desiccant unit was examined as a candidate of the regeneration method of the system, and the performance of the microwave regeneration was compared with that of the hot air regeneration in terms of the supply air humidity ratio, outdoor air based COP, and the process air temperatures. The results revealed the effects of the switching time and the irradiation timing on the performance of the microwave irradiation.

  8. Fixed-bed gasification research using US coals. Volume 2. Gasification of Jetson bituminous coal

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-03-31

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report describes the gasification testing of Jetson bituminous coal. This Western Kentucky coal was gasified during an initial 8-day and subsequent 5-day period. Material flows and compositions are reported along with material and energy balances. Operational experience is also described. 4 refs., 24 figs., 17 tabs.

  9. The use of fixed bed absorbents for flexible operation on the SAGE gas processing plant

    SciTech Connect

    Carnell, P.J.H.; Joslin, K.W.; Woodham, P.R.

    1995-11-01

    Mobil North Sea Ltd. operates the SAGE Gas Terminal at St. Fergus, Scotland on behalf of the SAGE partners. This terminal is capable of processing 1,150 MMscfd of sour gas with the sales gas being delivered into the British Gas distribution network and NGL`s exported by pipelines to Shell`s NGL fractionation plant at Mossmorran and BP`s fractionation plant at Kinneil. In order to meet the specifications for the sales gas and NGL produced while processing different mixtures of three separate feed gases produced by three independently operated production platforms the SAGE Gas Terminal has utilized ICI Katalco`s PURASPEC{trademark} processes to provide flexibility and reduce cost. This paper discusses how and where these fixed bed processes are utilized.

  10. Fixed bed adsorption of 2-naphthalenesulfonic acid from aqueous solution by composite resin.

    PubMed

    Jia, Dong M; Li, Ya P; Li, Yue J; Li, Yong G; Li, Chang H

    2014-02-01

    Adsorption behavior of the iron impregnated, weakly basic resin D301 (Fe-D301) for removal of 2-naphthalenesulfonic acid (2-NSA) from aqueous solution was studied by using a fixed-bed column. The effects of process variables such as bed height, flow rate, and coexisting ions were investigated. The results indicated that the breakpoint and exhaustion point increased with increasing bed height and decreased with increasing 2-NSA flowrate. Experimental data showed a strong fit to the Bed Depth Service Time model. The coexisting ions in the 2-NSA solution had a clear effect on the breakthrough volume. The high extent of recovery of 2-NSA with good reproducibility provided an effective method for the separation of 2-NSA by the adsorbent Fe-D301.

  11. Gas generator with fixed bed and reverse draught, to gasify solid combustible materials

    SciTech Connect

    Pillard, J.

    1982-08-17

    The invention relates to a gas generator with fixed bed and reverse draught, to gasify solid combustible materials. The gas generator according to the invention comprises starting from the top downwards, a loading compartment, a drying and pyrolysis enclosure, a combustion chamber, a rotary hearth plate and an ash tray. The wall of the combustion chamber is lined with a coil inside which flows part of the combustion air which is injected obliquely on the top periphery of the chamber. The center of the combustion chamber is occupied by a core which is driven in rotation by the hearth plate and which is covered by a deflector. Another part of the combustion air is injected through the core at the top of the combustion chamber. The invention finds an application in the gasification of all types of combustible solid material, which may or may not be associated to their carbonization.

  12. Biological treatment of gold ore cyanidation wastewater in fixed bed reactors.

    PubMed

    Dictor, M C; Battaglia-Brunet, F; Morin, D; Bories, A; Clarens, M

    1997-01-01

    The treatment of a cyanidation effluent containing thiocyanate, free cyanide, and complexed cyanide was continuously performed for a period of 6 months. Activated carbon, pozzolana, and a mixture of pumice stone and zeolite were tested as supports in fixed bed reactors. Activated carbon adsorbed the different forms of cyanide. In contrast, the other supports did not remove any pollutants from the effluent during an adsorption experiment. All supports successfully allowed fixation of bacteria. More than 90% of the thiocyanate was biologically decomposed into NH4+, CO2 and SO4(2-), even when increasing the feed flow-rate and the pollutant concentrations. Free and complexed cyanides were eliminated, probably through a combination of precipitation and biological degradation. The oxidation of ammonium into nitrate was only performed by the activated carbon-containing column and with the more diluted feeding. The nitrification process was inhibited in all reactors when the cyanide concentrations and feed flow-rates were increased.

  13. Gasification of biomass in a fixed bed downdraft gasifier--a realistic model including tar.

    PubMed

    Barman, Niladri Sekhar; Ghosh, Sudip; De, Sudipta

    2012-03-01

    This study presents a model for fixed bed downdraft biomass gasifiers considering tar also as one of the gasification products. A representative tar composition along with its mole fractions, as available in the literature was used as an input parameter within the model. The study used an equilibrium approach for the applicable gasification reactions and also considered possible deviations from equilibrium to further upgrade the equilibrium model to validate a range of reported experimental results. Heat balance was applied to predict the gasification temperature and the predicted values were compared with reported results in literature. A comparative study was made with some reference models available in the literature and also with experimental results reported in the literature. Finally a predicted variation of performance of the gasifier by this validated model for different air-fuel ratio and moisture content was also discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Conversion of Xylose to Furfuryl Alcohol and 2-Methylfuran in a Continuous Fixed-Bed Reactor.

    PubMed

    Cui, Jinglei; Tan, Jingjing; Cui, Xiaojing; Zhu, Yulei; Deng, Tiansheng; Ding, Guoqiang; Li, Yongwang

    2016-06-08

    An efficient process was designed for the synthesis of furfuryl alcohol and 2-methylfuran from xylose using a continuous fixed-bed reactor over a catalyst combining Hβ zeolite and Cu/ZnO/Al2 O3 in γ-butyrolactone (GBL)/water as solvent. The cooperative effect of Hβ zeolite and GBL facilitated the dehydration of xylose and enhanced largely the furfural yield. The production of furfuryl alcohol and 2-methylfuran can be simply tuned by changing the hydrogenation temperature for furfural over the Cu/ZnO/Al2 O3 catalyst. The yield for furfuryl alcohol reached 87.2 % at 150 °C whereas a yield of 86.8 % was achieved for 2-methylfuran at 190 °C. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Completed Genome Sequence of the Anaerobic Iron-Oxidizing Bacterium Acidovorax ebreus Strain TPSY ▿

    PubMed Central

    Byrne-Bailey, Kathryne G.; Weber, Karrie A.; Chair, Antinea H.; Bose, Saumyaditya; Knox, Traci; Spanbauer, Trisha L.; Chertkov, Olga; Coates, John D.

    2010-01-01

    Acidovorax ebreus strain TPSY is the first anaerobic nitrate-dependent Fe(II) oxidizer for which there is a completed genome sequence. Preliminary protein annotation revealed an organism optimized for survival in a complex environmental system. Here, we briefly report the completed and annotated genome sequence of strain TPSY. PMID:20023012

  16. Arsenic removal via ZVI in a hybrid spouted vessel/fixed bed filter system

    PubMed Central

    Calo, Joseph M.; Madhavan, Lakshmi; Kirchner, Johannes; Bain, Euan J.

    2012-01-01

    The description and operation of a novel, hybrid spouted vessel/fixed bed filter system for the removal of arsenic from water are presented. The system utilizes zero-valent iron (ZVI) particles circulating in a spouted vessel that continuously generates active colloidal iron corrosion products via the “self-polishing” action between ZVI source particles rolling in the moving bed that forms on the conical bottom of the spouted vessel. This action also serves as a “surface renewal” mechanism for the particles that provides for maximum utilization of the ZVI material. (Results of batch experiments conducted to examine this mechanism are also presented.) The colloidal material produced in this fashion is continuously captured and concentrated in a fixed bed filter located within the spouted vessel reservoir wherein arsenic complexation occurs. It is demonstrated that this system is very effective for arsenic removal in the microgram per liter arsenic concentration (i.e., drinking water treatment) range, reducing 100 μg/L of arsenic to below detectable levels (≪10 μg/L) in less than an hour. A mechanistic analysis of arsenic behavior in the system is presented, identifying the principal components of the population of active colloidal material for arsenic removal that explains the experimental observations and working principles of the system. It is concluded that the apparent kinetic behavior of arsenic in systems where colloidal (i.e., micro/nano) iron corrosion products are dominant can be complex and may not be explained by simple first or zeroth order kinetics. PMID:22539917

  17. Numerical modelling of biomass combustion: Solid conversion processes in a fixed bed furnace

    NASA Astrophysics Data System (ADS)

    Karim, Md. Rezwanul; Naser, Jamal

    2017-06-01

    Increasing demand for energy and rising concerns over global warming has urged the use of renewable energy sources to carry a sustainable development of the world. Bio mass is a renewable energy which has become an important fuel to produce thermal energy or electricity. It is an eco-friendly source of energy as it reduces carbon dioxide emissions. Combustion of solid biomass is a complex phenomenon due to its large varieties and physical structures. Among various systems, fixed bed combustion is the most commonly used technique for thermal conversion of solid biomass. But inadequate knowledge on complex solid conversion processes has limited the development of such combustion system. Numerical modelling of this combustion system has some advantages over experimental analysis. Many important system parameters (e.g. temperature, density, solid fraction) can be estimated inside the entire domain under different working conditions. In this work, a complete numerical model is used for solid conversion processes of biomass combustion in a fixed bed furnace. The combustion system is divided in to solid and gas phase. This model includes several sub models to characterize the solid phase of the combustion with several variables. User defined subroutines are used to introduce solid phase variables in commercial CFD code. Gas phase of combustion is resolved using built-in module of CFD code. Heat transfer model is modified to predict the temperature of solid and gas phases with special radiation heat transfer solution for considering the high absorptivity of the medium. Considering all solid conversion processes the solid phase variables are evaluated. Results obtained are discussed with reference from an experimental burner.

  18. Integrated operation of a pressurized fixed-bed gasifier, hot gas desulfurization system, and turbine simulator

    SciTech Connect

    Bevan, S.; Ayala, R.E.; Feitelberg, A.; Furman, A.

    1995-11-01

    The overall objective of the General Electric Hot Gas Cleanup (HGCU) Program is to develop a commercially viable technology to remove sulfur, particulates, and halogens from a high-temperature fuel gas stream using a moving bed, regenerable mixed metal oxide sorbent based process. The HGCU Program is based on the design and demonstration of the HGCU system in a test facility made up of a pilot-scale fixed bed gasifier, a HGCU system, and a turbine simulator in Schenectady, NY, at the General Electric Research and Development Center. The objectives of the turbine simulator testing are (1) to demonstrate the suitability of fuel gas processed by the HGCU system for use in state-of-the-art gas turbines firing at 2,350 F rotor inlet temperature and (2) to quantify the combustion characteristics and emissions on low-Btu fuel gas. The turbine simulator program also includes the development and operation of experimental combustors based on the rich-quench-lean concept (RQL) to minimize the conversion of ammonia and other fuel-bound nitrogen species to NO{sub x} during combustion. The HGCU system and turbine simulator have been designed to process approximately 8,000 lb/hr of low heating value fuel gas produced by the GE fixed bed gasifier. The HGCU system has utilized several mixed metal oxide sorbents, including zinc ferrite, zinc titanate, and Z-Sorb, with the objective of demonstrating good sulfur removal and mechanical attrition resistance as well as economic cost characteristics. Demonstration of halogen removal and the characterization of alkali and trace metal concentrations in the fuel gas are subordinate objectives of the overall program. This report describes the results of several long-duration pilot tests.

  19. Anaerobic digestion of tannery waste: semi-continuous and anaerobic sequencing batch reactor processes.

    PubMed

    Zupancic, Gregor D; Jemec, A

    2010-01-01

    Disposal of the vast amounts of tannery waste that are currently generated is a significant problem. Anaerobic treatment of different types of tannery waste (fleshings, skin trimmings and wastewater sludge) was investigated. The biochemical methane potential is the same at 37 degrees C or 55 degrees C and an assay of this was shown to be an appropriate screening tool with which to estimate the susceptibility of a substrate to anaerobic digestion. The start-up procedure of a tannery waste thermophilic anaerobic digestion in 100 days using seed from mesophilic digester processing municipal sludge is presented. The specific methane production potential at 55 degrees C is estimated to be 0.617 m(3)kg(-1) of volatile suspended solids for tannery waste sludge, 0.377 m(3)kg(-1) for tannery waste trimmings and 0.649 m(3)kg(-1) for tannery waste fleshings. Additional concerns such as chromium content, salinity and temperature fluctuations were also addressed. Chromium content and salinity showed no adverse effects; however a reactor temperature reduction of 4.4 degrees C led to a drop in biogas production of 25%, indicating a requirement to keep the temperature constant at 55 degrees C.

  20. Fixed-bed gasification research using US coals. Volume 11. Gasification of Minnesota peat. [Peat pellets and peat sods

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-05-01

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a coooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report is the eleventh volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This specific report describes the gasification of peat pellets and peat sods during 3 different test periods. 2 refs., 20 figs., 13 tabs.

  1. Deep sequencing-based analysis of the anaerobic stimulon in Neisseria gonorrhoeae

    PubMed Central

    2011-01-01

    Background Maintenance of an anaerobic denitrification system in the obligate human pathogen, Neisseria gonorrhoeae, suggests that an anaerobic lifestyle may be important during the course of infection. Furthermore, mounting evidence suggests that reduction of host-produced nitric oxide has several immunomodulary effects on the host. However, at this point there have been no studies analyzing the complete gonococcal transcriptome response to anaerobiosis. Here we performed deep sequencing to compare the gonococcal transcriptomes of aerobically and anaerobically grown cells. Using the information derived from this sequencing, we discuss the implications of the robust transcriptional response to anaerobic growth. Results We determined that 198 chromosomal genes were differentially expressed (~10% of the genome) in response to anaerobic conditions. We also observed a large induction of genes encoded within the cryptic plasmid, pJD1. Validation of RNA-seq data using translational-lacZ fusions or RT-PCR demonstrated the RNA-seq results to be very reproducible. Surprisingly, many genes of prophage origin were induced anaerobically, as well as several transcriptional regulators previously unknown to be involved in anaerobic growth. We also confirmed expression and regulation of a small RNA, likely a functional equivalent of fnrS in the Enterobacteriaceae family. We also determined that many genes found to be responsive to anaerobiosis have also been shown to be responsive to iron and/or oxidative stress. Conclusions Gonococci will be subject to many forms of environmental stress, including oxygen-limitation, during the course of infection. Here we determined that the anaerobic stimulon in gonococci was larger than previous studies would suggest. Many new targets for future research have been uncovered, and the results derived from this study may have helped to elucidate factors or mechanisms of virulence that may have otherwise been overlooked. PMID:21251255

  2. Deep sequencing-based analysis of the anaerobic stimulon in Neisseria gonorrhoeae.

    PubMed

    Isabella, Vincent M; Clark, Virginia L

    2011-01-20

    Maintenance of an anaerobic denitrification system in the obligate human pathogen, Neisseria gonorrhoeae, suggests that an anaerobic lifestyle may be important during the course of infection. Furthermore, mounting evidence suggests that reduction of host-produced nitric oxide has several immunomodulary effects on the host. However, at this point there have been no studies analyzing the complete gonococcal transcriptome response to anaerobiosis. Here we performed deep sequencing to compare the gonococcal transcriptomes of aerobically and anaerobically grown cells. Using the information derived from this sequencing, we discuss the implications of the robust transcriptional response to anaerobic growth. We determined that 198 chromosomal genes were differentially expressed (~10% of the genome) in response to anaerobic conditions. We also observed a large induction of genes encoded within the cryptic plasmid, pJD1. Validation of RNA-seq data using translational-lacZ fusions or RT-PCR demonstrated the RNA-seq results to be very reproducible. Surprisingly, many genes of prophage origin were induced anaerobically, as well as several transcriptional regulators previously unknown to be involved in anaerobic growth. We also confirmed expression and regulation of a small RNA, likely a functional equivalent of fnrS in the Enterobacteriaceae family. We also determined that many genes found to be responsive to anaerobiosis have also been shown to be responsive to iron and/or oxidative stress. Gonococci will be subject to many forms of environmental stress, including oxygen-limitation, during the course of infection. Here we determined that the anaerobic stimulon in gonococci was larger than previous studies would suggest. Many new targets for future research have been uncovered, and the results derived from this study may have helped to elucidate factors or mechanisms of virulence that may have otherwise been overlooked.

  3. Thin-film fixed-bed reactor (TFFBR) for solar photocatalytic inactivation of aquaculture pathogen Aeromonas hydrophila.

    PubMed

    Khan, Sadia J; Reed, Robert H; Rasul, Mohammad G

    2012-01-13

    Outbreaks of infectious diseases by microbial pathogens can cause substantial losses of stock in aquaculture systems. There are several ways to eliminate these pathogens including the use of antibiotics, biocides and conventional disinfectants, but these leave undesirable chemical residues. Conversely, using sunlight for disinfection has the advantage of leaving no chemical residue and is particularly suited to countries with sunny climates. Titanium dioxide (TiO2) is a photocatalyst that increases the effectiveness of solar disinfection. In recent years, several different types of solar photocatalytic reactors coated with TiO2 have been developed for waste water and drinking water treatment. In this study a thin-film fixed-bed reactor (TFFBR), designed as a sloping flat plate reactor coated with P25 DEGUSSA TiO2, was used. The level of inactivation of the aquaculture pathogen Aeromonas hydrophila ATCC 35654 was determined after travelling across the TFFBR under various natural sunlight conditions (300-1200 W m(-2)), at 3 different flow rates (4.8, 8.4 and 16.8 L h(-1)). Bacterial numbers were determined by conventional plate counting using selective agar media, cultured (i) under conventional aerobic conditions to detect healthy cells and (ii) under conditions designed to neutralise reactive oxygen species (agar medium supplemented with the peroxide scavenger sodium pyruvate at 0.05% w/v, incubated under anaerobic conditions), to detect both healthy and sub-lethally injured (oxygen-sensitive) cells. The results clearly demonstrate that high sunlight intensities (≥ 600 W m(-2)) and low flow rates (4.8 L h(-1)) provided optimum conditions for inactivation of A. hydrophila ATCC 3564, with greater overall inactivation and fewer sub-lethally injured cells than at low sunlight intensities or high flow rates. Low sunlight intensities resulted in reduced overall inactivation and greater sub-lethal injury at all flow rates. This is the first demonstration of the

  4. Thin-film fixed-bed reactor (TFFBR) for solar photocatalytic inactivation of aquaculture pathogen Aeromonas hydrophila

    PubMed Central

    2012-01-01

    Background Outbreaks of infectious diseases by microbial pathogens can cause substantial losses of stock in aquaculture systems. There are several ways to eliminate these pathogens including the use of antibiotics, biocides and conventional disinfectants, but these leave undesirable chemical residues. Conversely, using sunlight for disinfection has the advantage of leaving no chemical residue and is particularly suited to countries with sunny climates. Titanium dioxide (TiO2) is a photocatalyst that increases the effectiveness of solar disinfection. In recent years, several different types of solar photocatalytic reactors coated with TiO2 have been developed for waste water and drinking water treatment. In this study a thin-film fixed-bed reactor (TFFBR), designed as a sloping flat plate reactor coated with P25 DEGUSSA TiO2, was used. Results The level of inactivation of the aquaculture pathogen Aeromonas hydrophila ATCC 35654 was determined after travelling across the TFFBR under various natural sunlight conditions (300-1200 W m-2), at 3 different flow rates (4.8, 8.4 and 16.8 L h-1). Bacterial numbers were determined by conventional plate counting using selective agar media, cultured (i) under conventional aerobic conditions to detect healthy cells and (ii) under conditions designed to neutralise reactive oxygen species (agar medium supplemented with the peroxide scavenger sodium pyruvate at 0.05% w/v, incubated under anaerobic conditions), to detect both healthy and sub-lethally injured (oxygen-sensitive) cells. The results clearly demonstrate that high sunlight intensities (≥ 600 W m-2) and low flow rates (4.8 L h-1) provided optimum conditions for inactivation of A. hydrophila ATCC 3564, with greater overall inactivation and fewer sub-lethally injured cells than at low sunlight intensities or high flow rates. Low sunlight intensities resulted in reduced overall inactivation and greater sub-lethal injury at all flow rates. Conclusions This is the first

  5. Anaerobic sequencing batch reactor in pilot scale for treatment of tofu industry wastewater

    NASA Astrophysics Data System (ADS)

    Rahayu, Suparni Setyowati; Purwanto, Budiyono

    2015-12-01

    The small industry of tofu production process releases the waste water without being processed first, and the wastewater is directly discharged into water. In this study, Anaerobic Sequencing Batch Reactor in Pilot Scale for Treatment of Tofu Industry was developed through an anaerobic process to produce biogas as one kind of environmentally friendly renewable energy which can be developed into the countryside. The purpose of this study was to examine the fundamental characteristics of organic matter elimination of industrial wastewater with small tofu effective method and utilize anaerobic active sludge with Anaerobic Sequencing Bath Reactor (ASBR) to get rural biogas as an energy source. The first factor is the amount of the active sludge concentration which functions as the decomposers of organic matter and controlling selectivity allowance to degrade organic matter. The second factor is that HRT is the average period required substrate to react with the bacteria in the Anaerobic Sequencing Bath Reactor (ASBR).The results of processing the waste of tofu production industry using ASBR reactor with active sludge additions as starter generates cumulative volume of 5814.4 mL at HRT 5 days so that in this study it is obtained the conversion 0.16 L of CH4/g COD and produce biogas containing of CH4: 81.23% and CO2: 16.12%. The wastewater treatment of tofu production using ASBR reactor is able to produce renewable energy that has economic value as well as environmentally friendly by nature.

  6. Anaerobic sequencing batch reactor in pilot scale for treatment of tofu industry wastewater

    SciTech Connect

    Rahayu, Suparni Setyowati; Purwanto, Budiyono

    2015-12-29

    The small industry of tofu production process releases the waste water without being processed first, and the wastewater is directly discharged into water. In this study, Anaerobic Sequencing Batch Reactor in Pilot Scale for Treatment of Tofu Industry was developed through an anaerobic process to produce biogas as one kind of environmentally friendly renewable energy which can be developed into the countryside. The purpose of this study was to examine the fundamental characteristics of organic matter elimination of industrial wastewater with small tofu effective method and utilize anaerobic active sludge with Anaerobic Sequencing Bath Reactor (ASBR) to get rural biogas as an energy source. The first factor is the amount of the active sludge concentration which functions as the decomposers of organic matter and controlling selectivity allowance to degrade organic matter. The second factor is that HRT is the average period required substrate to react with the bacteria in the Anaerobic Sequencing Bath Reactor (ASBR).The results of processing the waste of tofu production industry using ASBR reactor with active sludge additions as starter generates cumulative volume of 5814.4 mL at HRT 5 days so that in this study it is obtained the conversion 0.16 L of CH{sub 4}/g COD and produce biogas containing of CH{sub 4}: 81.23% and CO{sub 2}: 16.12%. The wastewater treatment of tofu production using ASBR reactor is able to produce renewable energy that has economic value as well as environmentally friendly by nature.

  7. Continuous synthesis of methanol: heterogeneous hydrogenation of ethylene carbonate over Cu/HMS catalysts in a fixed bed reactor system.

    PubMed

    Chen, Xi; Cui, Yuanyuan; Wen, Chao; Wang, Bin; Dai, Wei-Lin

    2015-09-18

    Continuous fixed-bed catalytic hydrogenation of ethylene carbonate (EC) to methanol and ethylene glycol (EG), an emerging synthetic process of methanol via indirect conversion of CO2, was successfully performed over Cu/HMS catalysts prepared by the ammonia evaporation (AE) method. The catalysts possessed superb performance with a conversion of 100% and a selectivity to methanol of 74%.

  8. Application of next-generation sequencing methods for microbial monitoring of anaerobic digestion of lignocellulosic biomass.

    PubMed

    Bozan, Mahir; Akyol, Çağrı; Ince, Orhan; Aydin, Sevcan; Ince, Bahar

    2017-08-04

    The anaerobic digestion of lignocellulosic wastes is considered an efficient method for managing the world's energy shortages and resolving contemporary environmental problems. However, the recalcitrance of lignocellulosic biomass represents a barrier to maximizing biogas production. The purpose of this review is to examine the extent to which sequencing methods can be employed to monitor such biofuel conversion processes. From a microbial perspective, we present a detailed insight into anaerobic digesters that utilize lignocellulosic biomass and discuss some benefits and disadvantages associated with the microbial sequencing techniques that are typically applied. We further evaluate the extent to which a hybrid approach incorporating a variation of existing methods can be utilized to develop a more in-depth understanding of microbial communities. It is hoped that this deeper knowledge will enhance the reliability and extent of research findings with the end objective of improving the stability of anaerobic digesters that manage lignocellulosic biomass.

  9. Genome Sequence of the Facultative Anaerobe Oerskovia enterophila DFA-19 (DSM 43852T)

    PubMed Central

    Jag, Vanessa; Bengelsdorf, Frank R.; Daniel, Rolf

    2016-01-01

    Here, we report the draft genome sequence of Oerskovia enterophila DFA-19 (DSM 43852T), a facultative anaerobe soil bacterium, which was originally isolated from millipede feces and first described as Promicromonospora enterophila. The genome consists of a circular chromosome comprising approximately 4.65 Mb and 4,044 predicted protein-encoding genes. PMID:27634998

  10. Metal precipitation in an ethanol-fed, fixed-bed sulphate-reducing bioreactor.

    PubMed

    Kousi, Pavlina; Remoundaki, Emmanouela; Hatzikioseyian, Artin; Battaglia-Brunet, Fabienne; Joulian, Catherine; Kousteni, Vassiliki; Tsezos, Marios

    2011-05-30

    A batch upflow fixed-bed sulphate-reducing bioreactor has been set up and monitored for the treatment of synthetic solutions containing divalent iron (100mg/L and 200mg/L), zinc (100mg/L and 200mg/L), copper (100mg/L and 200mg/L), nickel (100mg/L and 200mg/L) and sulphate (1700 mg/L and 2130 mg/L) at initial pH 3-3.5, using ethanol as the sole electron donor. The reactor has been operated at the theoretical stoichiometric ethanol/sulphate ratio. Complete oxidation of ethanol has been achieved through complete oxidation of the intermediately, microbially produced acetate. This is mainly attributed to the presence of Desulfobacter postgatei species which dominated the sulphate-reducing community in the reactor. The reduction of sulphate was limited to about 85%. Quantitative precipitation of the soluble metal ions has been achieved. XRD and SEM-EDS analyses performed on samples of the produced sludge showed poorly crystalline phases of marcasite, covellite and wurtzite as well as several mixed metal sulphides. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Process Development of Adenoviral Vector Production in Fixed Bed Bioreactor: From Bench to Commercial Scale.

    PubMed

    Lesch, Hanna P; Heikkilä, Kati M; Lipponen, Eevi M; Valonen, Piia; Müller, Achim; Räsänen, Eva; Tuunanen, Tarja; Hassinen, Minna M; Parker, Nigel; Karhinen, Minna; Shaw, Robert; Ylä-Herttuala, Seppo

    2015-08-01

    Large-scale vector manufacturing for phase III and beyond has proven to be challenging. Upscaling the process with suspension cells is increasingly feasible, but many viral production applications are still applicable only in adherent settings. Scaling up the adherent system has proven to be troublesome. The iCELLis(®) disposable fixed-bed bioreactors offer a possible option for viral vector manufacturing in large quantities in an adherent environment. In this study, we have optimized adenovirus serotype 5 manufacturing using iCELLis Nano with a cultivation area up to 4 m(2). HEK293 cell cultivation, infection, and harvest of the virus (by lysing the cells inside the bioreactor) proved possible, reaching total yield of up to 1.6×10(14) viral particles (vp)/batch. The iCELLis 500 is designed to satisfy demand for large-scale requirements. Inoculating a large quantity of cell mass into the iCELLis 500 was achieved by first expanding the cell mass in suspension. Upscaling the process into an iCELLis 500/100 m(2) cultivation area cassette was practical and produced up to 6.1×10(15) vp. Flask productivity per cm(2) in iCELLis Nano and iCELLis 500 was in the same range. As a conclusion, we showed for the first time that iCELLis 500 equipment has provided an effective way to manufacture large batches of adenoviral vectors.

  12. Color removal from textile wastewater by using treated flute reed in a fixed bed column.

    PubMed

    Inthorn, Duangrat; Tipprasertsin, Kannika; Thiravetyan, Paitip; Khan, Eakalak

    2010-01-01

    This study investigated the ability of acid treated flute reed to adsorb color (dye) from synthetic reactive dye solutions, and actual dyeing and printing textile wastewaters in a laboratory scale fixed bed column. The effects of particle size, initial reactive dye concentration, bed depth and flow rate on adsorption performances were examined. The results from experiments with synthetic reactive dye solutions showed that the volume treated (until the breakthrough occurred) increased with decreasing particle size, influent reactive dye concentration and flow rate, and increasing bed depth. The bed depth service time model was suitable for describing the experimental data. The treated flute reed was able to reduce color efficiently, 99% for dyeing textile wastewater with ten adsorption columns in series and 78% for printing textile wastewater with a single adsorption column. The difference in the numbers of columns used for the two types of actual textile wastewater led to a substantial discrepancy in suspended solids removal, 99% for dyeing wastewater and 12% for printing wastewater. Similar pH and chemical oxygen demand (COD) results were obtained for the two types of textile wastewater. The acid pretreatment of flute reed resulted in dramatic decreases in pH after the adsorption and very acidic effluents (pH 3). Increases of COD after the adsorption due to organic leaching from the treated flute reed were observed. A different pretreatment method to solve these pH and COD problems is needed before flute reed can be used in practice.

  13. Co-pyrolysis of rice straw and polypropylene using fixed-bed pyrolyzer

    NASA Astrophysics Data System (ADS)

    Izzatie, N. I.; Basha, M. H.; Uemura, Y.; Mazlan, M. A.; Hashim, M. S. M.; Amin, N. A. M.; Hamid, M. F.

    2016-11-01

    The present work encompasses the impact of temperature (450, 500, 550, 600 °C) on the properties of pyrolysis oil and on other product yield for the co-pyrolysis of Polypropylene (PP) plastics and rice straw. Co-pyrolysis of PP plastic and rice straw were conducted in a fixed-bed drop type pyrolyzer under an inert condition to attain maximum oil yield. Physically, the pyrolysis oil is dark-brown in colour with free flowing and has a strong acrid smell. Copyrolysis between these typically obtained in maximum pyrolysis oil yields up to 69% by ratio 1:1 at a maximum temperature of 550 °C. From the maximum yield of pyrolysis oil, characterization of pyrolysis product and effect of biomass type of the composition were evaluated. Pyrolysis oil contains a high water content of 66.137 wt.%. Furfural, 2- methylnaphthalene, tetrahydrofuran (THF), toluene and acetaldehyde were the major organic compounds found in pyrolysis oil of rice straw mixed with PP. Bio-char collected from co-pyrolysis of rice straw mixed with PP plastic has high calorific value of 21.190 kJ/g and also carbon content with 59.02 wt.% and could contribute to high heating value. The non-condensable gases consist of hydrogen, carbon monoxide, and methane as the major gas components.

  14. Biofilm development in fixed bed biofilm reactors: experiments and simple models for engineering design purposes.

    PubMed

    Szilágyi, N; Kovács, R; Kenyeres, I; Csikor, Zs

    2013-01-01

    Biofilm development in a fixed bed biofilm reactor system performing municipal wastewater treatment was monitored aiming at accumulating colonization and maximum biofilm mass data usable in engineering practice for process design purposes. Initially a 6 month experimental period was selected for investigations where the biofilm formation and the performance of the reactors were monitored. The results were analyzed by two methods: for simple, steady-state process design purposes the maximum biofilm mass on carriers versus influent load and a time constant of the biofilm growth were determined, whereas for design approaches using dynamic models a simple biofilm mass prediction model including attachment and detachment mechanisms was selected and fitted to the experimental data. According to a detailed statistical analysis, the collected data have not allowed us to determine both the time constant of biofilm growth and the maximum biofilm mass on carriers at the same time. The observed maximum biofilm mass could be determined with a reasonable error and ranged between 438 gTS/m(2) carrier surface and 843 gTS/m(2), depending on influent load, and hydrodynamic conditions. The parallel analysis of the attachment-detachment model showed that the experimental data set allowed us to determine the attachment rate coefficient which was in the range of 0.05-0.4 m d(-1) depending on influent load and hydrodynamic conditions.

  15. Fixed bed pyrolysis of biomass solid waste for bio-oil

    NASA Astrophysics Data System (ADS)

    Islam, Mohammad Nurul; Ali, Mohamed Hairol Md; Haziq, Miftah

    2017-08-01

    Biomass solid waste in the form of rice husk particle is pyrolyzed in a fixed bed stainless steel pyrolysis reactor of 50 mm diameter and 50 cm length. The biomass solid feedstock is prepared prior to pyrolysis. The reactor bed is heated by means of a cylindrical heater of biomass source. A temperature of 500°C is maintained with an apperent vapor residence time of 3-5 sec. The products obtained are liquid bio-oil, solid char and gases. The liquid product yield is found to be 30% by weight of solid biomass feedstock while the solid product yield is found to be 35% by weight of solid biomass feedtock, the rest is gas. The bio-oil is a single-phase brownish color liquid of acrid smell. The heating value of the oil is determined to be 25 MJ/kg. The density and pH value are found to be 1.125 kg/m3 and 3.78 respectively.

  16. Heavy metals removal in fixed-bed column by the macro fungus Pycnoporus sanguineus.

    PubMed

    Zulfadhly, Z; Mashitah, M D; Bhatia, S

    2001-01-01

    The ability of Pycnoporus sanguineus to adsorb heavy metals from aqueous solution was investigated in fixed-bed column studies. The experiments were conducted to study the effect of important design parameters such as column bed height, flow rate and initial concentration of solution. The breakthrough profiles were obtained in these studies. A mathematical model based on external mass transfer and pore diffusion was used for the prediction of mass transfer coefficient and effective diffusivity of metals in macro-fungi bed. Experimental breakthrough profiles were compared with the simulated breakthrough profiles obtained from the mathematical model. Bed Depth Service Time (BDST) model was used to analyse the experimental data and evaluated the performance of biosorption column. The BDST model parameters needed for the design of biosorption columns were evaluated for lead, copper and cadmium removal in the column. The columns were regenerated by eluting the metal ions using 0.1 M hydrochloric acid solution after the adsorption studies. The columns were subjected to repeated cycles of adsorption of same metal ions and desorption to evaluate the removal efficiency after adsorption-desorption.

  17. [Synthesis of diacylglycerol using immoblized regiospecific lipase in continuously operated fixed bed reactors].

    PubMed

    Meng, Xiang-He; Sun, Pei-Long; Yang, Kai; He, Rong-Jun; Mao, Zhong-Gui

    2005-05-01

    Diacylglycerol, DAG, because of its multifunctional and nutritional properties, attracted considerable attention recently. Enzymatic synthesis of diacylglycerols from linoleic acid was investigated in a solvent-free reaction in a continuously operated fixed bed reactors containing Lipozyme RM IM. By appropriate manipulation of the fluid-residence time, the relative proportions of the various acylglycerols in the effluent stream can be controlled. In addition, the presence of excess glycerol is effective for the removal of water produced during the esterification reactions. Under the conditions of molar ratio of linoleic acid to glycerol of 0.5, the immoblized enzyme maintained high stability and allowed the reaction to continue for 10 days without significant deterioration in enzyme activity. It was determined that the conversion of fatty acid, content of 1,3-DAG and volume efficiency of reactor reached optima under the conditions: a packaged-bed reactor(with a ratio of packed length to inner diameter of 7.8), reacting temperature at 65 degrees C, molar ratio of linoleic acid to glycerol of 0.5, and feeding flow rate of 1.2 mL/min.

  18. Impact of feedstock properties and operating conditions on sewage sludge gasification in a fixed bed gasifier.

    PubMed

    Werle, Sebastian

    2014-10-01

    This work presents results of experimental studies on the gasification process of granulated sewage sludge in a laboratory fixed bed gasifier. Nowadays, there is a large and pressing need for the development of thermal methods for sewage sludge disposal. Gasification is an example of thermal method that has several advantages over the traditional combustion. Gasification leads to a combustible gas, which can be used for the generation of useful forms of final energy. It can also be used in processes, such as the drying of sewage sludge directly in waste treatment plant. In the present work, the operating parameters were varied over a wide range. Parameters, such as air ratio λ = 0.12 to 0.27 and the temperature of air preheating t = 50 °C to 250 °C, were found to influence temperature distribution and syngas properties. The results indicate that the syngas heating value decreases with rising air ratio for all analysed cases: i.e. for both cold and preheated air. The increase in the concentration of the main combustible components was accompanied by a decrease in the concentration of carbon dioxide. Preheating of the gasification agent supports the endothermic gasification and increases hydrogen and carbon monoxide production. © The Author(s) 2014.

  19. Breakthrough behavior of granular ferric hydroxide (GFH) fixed-bed adsorption filters: modeling and experimental approaches.

    PubMed

    Sperlich, Alexander; Werner, Arne; Genz, Arne; Amy, Gary; Worch, Eckhard; Jekel, Martin

    2005-03-01

    Breakthrough curves (BTC) for the adsorption of arsenate and salicylic acid onto granulated ferric hydroxide (GFH) in fixed-bed adsorbers were experimentally determined and modeled using the homogeneous surface diffusion model (HSDM). The input parameters for the HSDM, the Freundlich isotherm constants and mass transfer coefficients for film and surface diffusion, were experimentally determined. The BTC for salicylic acid revealed a shape typical for trace organic compound adsorption onto activated carbon, and model results agreed well with the experimental curves. Unlike salicylic acid, arsenate BTCs showed a non-ideal shape with a leveling off at c/c0 approximately 0.6. Model results based on the experimentally derived parameters over-predicted the point of arsenic breakthrough for all simulated curves, lab-scale or full-scale, and were unable to catch the shape of the curve. The use of a much lower surface diffusion coefficient D(S) for modeling led to an improved fit of the later stages of the BTC shape, pointing on a time-dependent D(S). The mechanism for this time dependence is still unknown. Surface precipitation was discussed as one possible removal mechanism for arsenate besides pure adsorption interfering the determination of Freundlich constants and D(S). Rapid small-scale column tests (RSSCT) proved to be a powerful experimental alternative to the modeling procedure for arsenic.

  20. Development of a fixed bed gasifier model and optimal operating conditions determination

    NASA Astrophysics Data System (ADS)

    Dahmani, Manel; Périlhon, Christelle; Marvillet, Christophe; Hajjaji, Noureddine; Houas, Ammar; Khila, Zouhour

    2017-02-01

    The main objective of this study was to develop a fixed bed gasifier model of palm waste and to identify the optimal operating conditions to produce electricity from synthesis gas. First, the gasifier was simulated using Aspen PlusTM software. Gasification is a thermo-chemical process that has long been used, but it remains a perfectible technology. It means incomplete combustion of biomass solid fuel into synthesis gas through partial oxidation. The operating parameters (temperature and equivalence ratio (ER)) were thereafter varied to investigate their effect on the synthesis gas composition and to provide guidance for future research and development efforts in process design. The equivalence ratio is defined as the ratio of the amount of air actually supplied to the gasifier and the stoichiometric amount of air. Increasing ER decreases the production of CO and H2 and increases the production of CO2 and H2O while an increase in temperature increases the fraction of CO and H2. The results show that the optimum temperature to have a syngas able to be effectively used for power generation is 900°C and the optimum equivalence ratio is 0.1.

  1. Combustion tests of a turbine simulator burning low Btu fuel from a fixed bed gasifier

    SciTech Connect

    Cook, C.S.; Abuaf, N.; Feitelberg, A.S.; Hung, S.L.; Najewicz, D.J.; Samuels, M.S.

    1993-11-01

    One of the most efficient and environmentally compatible coal fueled power generation technologies is the integrated gasification combined cycle (IGCC) concept. Commercialization of the IGCC/HGCU concept requires successful development of combustion systems for high temperature low Btu fuel in gas turbines. Toward this goal, a turbine combustion system simulator has been designed, constructed, and fired with high temperature low Btu fuel. Fuel is supplied by a pilot scale fixed bed gasifier and hot gas desulfurization system. The primary objectives of this project are: (1) demonstration of long term operability of the turbine simulator with high temperature low Btu fuel; (2) measurement of NO{sub x}, CO, and particulate emissions; and (3) characterization of particulates in the fuel as well as deposits in the fuel nozzle, combustor, and first stage nozzle. In a related project, a reduced scale rich-quench-lean (RQL) gas turbine combustor has been designed, constructed, and fired with simulated low Btu fuel. The overall objective of this project is to develop an RQL combustor with lower conversion of fuel bound nitrogen (FBN) to NO{sub x} than a conventional combustor.

  2. Numerical simulation of gas concentration and dioxin formation for MSW combustion in a fixed bed.

    PubMed

    Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

    2015-07-01

    A numerical model was employed to simulate the combustion process in a fixed porous bed of municipal solid waste (MSW). Mass, momentum, energy and species conservation equations of the waste bed were set up to describe the incineration process. The rate of moisture evaporation, volatile matter devolatilization, char combustion, NOx production, and reduction and dioxin formation were calculated and established according to the local thermal conditions and waste property characteristics. Changes in the bed volume during incineration were calculated according to the reaction rate of the process. The simulation results were compared with experimental data, which shows that the incineration process of waste in the fixed bed was reasonably simulated. The simulation results of weight loss and solid temperature in the bed agree with the experimental data, which shows that the waste combustion rate is nearly constant in the middle of the incineration process, and that moisture evaporation takes up most of the time for the overall incineration experiment. The emission of gas species from the bed surface is also agreeably simulated, with O2, CO2, and CO concentrations in flue gas agreeing with the experimental data. The simulation results benefit the understanding of the combustion process in the waste bed as well as the design of incinerator grates.

  3. [Transformation of sulfur forms during coal pyrolysis and partial gasification in a fixed bed reactor].

    PubMed

    Li, Bin; Cao, Yan; Zhang, Jianmin; Huang, Jiejie; Wang, Yang; Chen, Fuyan

    2003-03-01

    The development of various process to the pre-desulfurization of coal was drawn more attention. In present study, the transformation of sulfur forms of three different ranks high sulfur coals during coal pyrolysis and partial gasification were investigated in a fixed bed reactor. The sulfur and carbon content analysis of original coal and coal char produced were determined by LECO SC-444 and wet chemical analysis according to Sugawara's method. The results showed that half of inorganic sulfur and partial of organic sulfur were removed during coal pyrolysis. And the sulfur removal was much more than carbon during pyrolysis process; and the sulfur in the coal char, especially the sulfide sulfur was removed completely during partial gasification process for both Datong coal and Xishan coal, the degree of sulfide sulfur removal could be increased with increasing temperature. At the same time, the results of Yima coal showed that the effect of fixed-sulfur by alkaline metals increased when the temperature was higher than 700 degrees C, which attribute to the increase of the fixed sulfur reaction rate and the decrease of mass-transfer limitation.

  4. Fixed bed testing of a molybdenum-promoted zinc titanate for hot gas desulfurization

    SciTech Connect

    Gasper-Galvin, L.D.; Mei, J.S.; Everitt, C.E.; Katta, S.

    1993-09-01

    The following conclusions were made, based upon this study of T-2535 molybdenum-promoted zinc titanate: (1) Results of the half-cycle sulfidation experiments showed that sorbent efficiency and capacity of this formulation of zinc titanate were weak functions of operating-bed temperature. Evidence of diffusion limitations on the sulfidation reaction were observed, particularly at superficial velocities greater than 30 cm/s (1 ft/s). Sorbent performance appeared to be affected by the concentration of reducing gases and/or water content of the simulated coal gas mixtures. Sorbent capacity and efficiency deteriorated during the first three cycles, but stabilized thereafter. (2) Sorbent spalling was observed and appeared to increase with sulfur loading. Possible causes of spalling may be attributed to the induced crystal lattice stresses due to the formation of ZnS and especially ZnSO{sub 4}, which have relative molar volumes that are approximately 1-1/2 and 3 times larger, respectively, than that of the original ZnO. (3) Based on these results, it is apparent that the molybdenum-promoted zinc titanate with Zn/Ti molar ratio of 1.91 may not be a suitable sorbent for hot gas desulfurization in the fixed bed reactor for the Pinon Pine project, due to problems with spalling and loss of reactivity during sulfidation/regeneration cycling.

  5. A novel fixed-bed reactor design incorporating an electrospun PVA/chitosan nanofiber membrane.

    PubMed

    Esmaeili, Akbar; Beni, Ali Aghababai

    2014-09-15

    In this research, a novel fixed-bed reactor was designed with a nanofiber membrane composed of a polyvinyl alcohol (PVA)/chitosan nanofiber blend prepared using an electrospinning technique. The applied voltage, tip-collector distance, and solution flow rate of the electrospinning process were 18 kV, 14.5 cm, and 0.5 mL h(-1), respectively. Brunauer-Emmett-Teller (BET) theory, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize and analyze the nanofiber membranes. Homogeneous electrospun nanofibers with an average diameter of 99.47 nm and surface area of 214.12 m(2)g(-1) were obtained. Adsorption experiments were carried out in a batch system to investigate the effect of different adsorption parameters such as pH, adsorbent dose, biomass dose, contact time, and temperature. The kinetic data, obtained at the optimal pH of 6, were analyzed by pseudo first-order and pseudo second-order kinetic models. Three isotherm models and thermodynamic parameters (ΔG°, ΔH°, and ΔS°) were applied to describe the equilibrium data of the metal ions adsorbed onto the PVA/chitosan nanofiber membrane. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Repowering applications using the British Gas/Lurgi fixed-bed gasification process

    SciTech Connect

    Shellhorse, V.H.; Garstang, J.H.; Herbert, P.K.; Kluttz, D.E.

    1995-09-01

    Steady economic growth, aging US base load power plants and Phase 2 of the 1990 Clean Air Act Amendment, will stimulate planning for new base-load capacity. What type of plants will be considered for the next increment of base load in the US? One option that is frequently discussed is the repowering of existing power plants with advanced technology, clean fuels and state-of-the-art environmental controls. Repowerings using natural gas have been implemented where supplies of natural gas are adequate and pricing is competitive. Integrated coal gasification combined cycle (CGCC) is another repowering option with growing interest based on support from the US Department of Energy Clean Coal Technology Program demonstration plants and experience gleaned from plants in several European countries. The British Gas Lurgi (BGL) fixed-bed, slagging gasifier is a state-of-the-art technology well suited for CGCC repowering applications. It offers dramatically reduced environmental emissions, simplicity, and improved thermal efficiency. This paper discusses such repowering applications.

  7. Efficient expansion of mesenchymal stromal cells in a disposable fixed bed culture system.

    PubMed

    Mizukami, Amanda; Orellana, Maristela D; Caruso, Sâmia R; de Lima Prata, Karen; Covas, Dimas T; Swiech, Kamilla

    2013-01-01

    The need for efficient and reliable technologies for clinical-scale expansion of mesenchymal stromal cells (MSC) has led to the use of disposable bioreactors and culture systems. Here, we evaluate the expansion of cord blood-derived MSC in a disposable fixed bed culture system. Starting from an initial cell density of 6.0 × 10(7) cells, after 7 days of culture, it was possible to produce of 4.2(±0.8) × 10(8) cells, which represents a fold increase of 7.0 (±1.4). After enzymatic retrieval from Fibra-Cell disks, the cells were able to maintain their potential for differentiation into adipocytes and osteocytes and were positive for many markers common to MSC (CD73, CD90, and CD105). The results obtained in this study demonstrate that MSC can be efficiently expanded in the culture system. This novel approach presents several advantages over the current expansion systems, based on culture flasks or microcarrier-based spinner flasks and represents a key element for MSC cellular therapy according to GMP compliant clinical-scale production system.

  8. Performance of a fixed-bed biofilm reactor with microbubble aeration in aerobic wastewater treatment.

    PubMed

    Zhang, Lei; Liu, Junliang; Liu, Chun; Zhang, Jing; Yang, Jingliang

    2016-01-01

    Microbubble aeration is supposed to be highly efficient for oxygen supply in aerobic wastewater treatment. In the present study, the performance of a fixed-bed biofilm reactor microbubble-aerated using a Shirasu porous glass (SPG) membrane system was investigated when treating synthetic municipal wastewater. The biofilm formation on the carriers was enhanced with microbubble aeration due to the strong adhesion of microbubbles to the solid surface. The dissolved oxygen concentration, the removals of chemical oxygen demand (COD) and nitrogen, and the oxygen utilization efficiency were influenced by the organic loading rate at a certain oxygen supply capacity. The relatively optimal organic loading rate was determined as 0.82 kgCOD/(m(3)d) when the oxygen supply capacity was 0.93 kgO(2)/(m(3)d), where COD and ammonia removal efficiencies were 91.7% and 53.9%, respectively. The corresponding SPG membrane area-based COD removal capacity was 6.88 kgCOD/(m(2)d). The oxygen utilization efficiency of microbubble aeration was obviously higher compared to conventional bubble aeration. The simultaneous nitrification and denitrification occurred in the biofilm reactor and the total nitrogen removal efficiency of 50.4% was achieved under these conditions. In addition, the increase in air supply capacity of the SPG membrane system was suggested to improve its energy utilization efficiency.

  9. Lead removal in fixed-bed columns by zeolite and sepiolite.

    PubMed

    Turan, Mustafa; Mart, Ugur; Yüksel, Baris; Celik, Mehmet S

    2005-09-01

    The removal efficiency of zeolite (clinoptilolite) and sepiolite from lead containing aqueous solutions was investigated. A series of experiments were conducted in batch-wise and fixed-bed columns. Synthetic wastewaters containing lead (50 mg l (-1)) and acetic acid (0.001 N) along with untreated and regenerated clinoptilolites and sepiolites were used in the adsorption studies. Batch tests were mainly conducted to isolate the magnitude of lead precipitation from real adsorption. Adsorption isotherms for both abstraction and adsorption were constructed. The removal of lead is found to be a sum of adsorption induced by ion exchange and precipitation of lead hydroxide. The breakthrough curves were obtained under different conditions by plotting the normalized effluent lead concentration (C/C0) versus bed volume (BV). The ion exchange capacity of sepiolite and clinoptilolite for lead removal showed good performance up to approximately 100 and 120 BV where the C/C0 remained below 0.1, respectively. The lead removal capacity of clinoptilolite bed from wastewater containing only lead yielded 45% higher performance compared to that of acetic acid partly due to a decrease in the effluent pH and consequently in precipitation. Also, the presence of acetic acid in the sepiolite column decreased the bed volumes treated by about 40%. Removal efficiency of lead-acetic system both in untreated clinoptilolite and sepiolite columns was found higher than that in regenerated columns.

  10. Biosorption of methylene blue from aqueous solution by rice husk in a fixed-bed column.

    PubMed

    Han, Runping; Wang, Yuanfeng; Yu, Weihong; Zou, Weihua; Shi, Jie; Liu, Hongmin

    2007-03-22

    In this study, the ability of rice husk to adsorb methylene blue (MB) from aqueous solution was investigated in a fixed-bed column. The effects of important parameters, such as the value of initial pH, existed salt, the flow rate, the influent concentration of MB and bed depth, were studied. The Thomas model was applied to adsorption of MB at different flow rate, influent concentration and bed depth to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design using non-linear regression. The bed-depth/service time analysis (BDST) model was also applied at different bed depth to predict the breakthrough curves. The two models were found suitable for describing the biosorption process of the dynamic behavior of the rice husk column. All the results suggested that rice husk as adsorbent to removal MB from solution be efficient, and the rate of biosorption process be rapid. When the flow rate was 8.2ml min(-1) and the influent concentration of MB was 50mgl(-1), the equilibrium adsorption biomass reached 4.41mgg(-1) according to Thomas model.

  11. Fixed bed column study for heavy metal removal using phosphate treated rice husk.

    PubMed

    Mohan, S; Sreelakshmi, G

    2008-05-01

    This paper reports the results of the study on the performance of low-cost adsorbent such as raw rice husk (RRH) and phosphate treated rice husk (PRH) in removing the heavy metals such as lead, copper, zinc and manganese. The adsorbent materials adopted were found to be an efficient media for the removal of heavy metals in continuous mode using fixed bed column. The column studies were conducted with 10 mg/l of individual and combined metal solution with a flow rate of 20 ml/min with different bed depths such as 10, 20 and 30 cm. The breakthrough time was also found to increase from 1.3 to 3.5 h for Pb(II), 4.0 to 9.0 h for Cu(II), 12.5 to 25.4h for Zn(II) and 3.0 to 11.3 h for Mn(II) with increase in bed height from 10 to 30 cm for PRH. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, etc. were calculated. It is found that the adsorption capacity and adsorption rate constant were increased and the minimum column bed depth required was reduced when the rice husk is treated with phosphate, when compared with that of RRH.

  12. Pyrolysis of Date palm waste in a fixed-bed reactor: Characterization of pyrolytic products.

    PubMed

    Bensidhom, Gmar; Ben Hassen-Trabelsi, Aïda; Alper, Koray; Sghairoun, Maher; Zaafouri, Kaouther; Trabelsi, Ismail

    2017-09-11

    The pyrolysis of several Tunisian Date Palm Wastes (DPW): Date Palm Rachis (DPR), Date Palm Leaflets (DPL), Empty Fruit Bunches (EFB) and Date Palm Glaich (DPG) was run using a fixed-bed reactor, from room temperature to 500°C, with 15°C/min as heating rate and -5°C as condensation temperature, in order to produce bio-oil, biochar and syngas. In these conditions, the bio-oil yield ranges from 17.03wt% for DPL to 25.99wt% for EFB. For the biochar, the highest yield (36.66wt%) was obtained for DPL and the lowest one (31.66wt%) was obtained from DPG while the syngas production varies from 39.10wt% for DPR to 46.31wt% DPL. The raw material and pyrolysis products have been characterized using elemental analysis thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM). The syngas composition has been characterized using gas analyzer. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Effects of mass transfer and hydrogen pressure on the fixed-bed pyrolysis of sunflower bagasse

    SciTech Connect

    Putun, E.; Kockar, O.M.; Gercel, F.

    1994-12-31

    There are a number of waste and biomass sources being considered as potential sources of fuels and chemical feedstocks. The economics for biomass pyrolysis are generally considered to be most favourable for (1) plants which grow abundantly and require little cultivation in and lands and (2) wastes available in relatively large quantities from agricultural plants, for example, sunflower and hazel nuts. For the former, one such group of plants is Euphorbiaceae which are characterised by their ability to produce a milky latex, an emulsion of about 30% w/w terpenoids in water. One species in the family, Euphorbia Rigida from Southwestern Anatolia, Turkey is cultivated in close proximity to the sunflower growing regions and their oil extraction plants. The Turkish sunflower oil industry generates 800,000 tons of extraction residue (bagasse) per annum. Thus, both sunflower wastes and latex-producing plants are being considered as feedstocks for a future thermochemical demonstration unit in Turkey. Pyrolysis at relatively high hydrogen pressures (hydropyrolysis) has not been widely investigated for biomass. A potential advantage of hydropyrolysis is the ability to upgrade tar vapours over hydroprocessing catalysts. Fixed-bed pyrolysis and hydropyrolysis experiments have been conducted on sunflower bagasse to assess the effects of mass transfer and hydrogen pressure on oil yield and quality.

  14. Co-pyrolysis of corn cob and waste cooking oil in a fixed bed.

    PubMed

    Chen, Guanyi; Liu, Cong; Ma, Wenchao; Zhang, Xiaoxiong; Li, Yanbin; Yan, Beibei; Zhou, Weihong

    2014-08-01

    Corn cob (CC) and waste cooking oil (WCO) were co-pyrolyzed in a fixed bed. The effects of various temperatures of 500 °C, 550 °C, 600 °C and CC/WCO mass ratios of 1:0, 1:0.1, 1:0.5, 1:1 and 0:1 were investigated, respectively. Results show that co-pyrolysis of CC/WCO produce more liquid and less bio-char than pyrolysis of CC individually. Bio-oil and bio-char yields were found to be largely dependent on temperature and CC/WCO ratios. GC/MS of bio-oil show it consists of different classes and amounts of organic compounds other than that from CC pyrolysis. Temperature of 550 °C and CC/WCO ratio of 1:1 seem to be the optimum considering high bio-oil yields (68.6 wt.%) and good bio-oil properties (HHV of 32.78 MJ/kg). In this case, bio-char of 24.96 MJ/kg appears attractive as a renewable source, while gas with LHV of 16.06 MJ/Nm(3) can be directly used in boilers as fuel. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Comparison of slurry versus fixed-bed reactor costs for indirect liquefaction applications. A supplement to final report: Design of slurry reactor for indirect liquefaction applications

    SciTech Connect

    Prakash, A.; Bendale, P.G.

    1991-12-01

    This work is a comparative evaluation of slurry reactors and fixed-bed reactors, with special emphasis on cost. Relative differences between slurry reactors and fixed-bed reactors have been pointed out in previous reviews; the differences pertinent to indirect liquefaction are summarized here. Design of both types is outlined.

  16. Evaluation of the behavior of Colombian coals during the combustion in fixed bed

    SciTech Connect

    Giraldo, M.; Chejne, F.; Hill, A.

    2000-07-01

    The improvements in the technological processes that have coal as energy source must be based on the knowledge of physical and chemical properties of coal and in the knowledge of its evolution during the combustion process. These characteristics are involved in the coal behavior. Moreover, the coal porosity has an important relevance on the reaction rate and in diverse physical and chemical properties, and therefore, is a key parameter in the usefulness of coal. This project includes studies about Colombian coal combustion and its kinetic behavior. The coal was characterized and classified by particle size,and origin. In this research project, the physical and chemical properties of coal that affect its applicability in different kinds of technological processes have been studied as well as the characteristics that could be related to pollutant generation. The study considers the following issues: the types and level of criteria pollutant precursor compounds such as sulfur and nitrogen in coal, the influence of particle size and porosity in the generation of pollutant species, the participation of pollutant species in the combustion process, and basic properties such as heat capacity, and heat effects related to the conversion of coal during heating test. Coal from Antioquia, Valle del Cauca and Cundinamarca Regions were used. These coals are used domestically by the industrial and power sector. Particle sizes of 4, 2.5 and 1 cm were used from each one of these coals. The combustion tests were done in a fixed bed pilot furnace. The amount of air used was controlled during the experiment. In addition, air and gas flow, concentration and temperatures were registered. This paper presents a description of: characteristics of each test, composition of generated gases, and the influence of the particle size and coal origin in the pollutant emissions, also includes the results of test done in different samples took along each test.

  17. Flow, turbulence, and drag associated with engineered log jams in a fixed-bed experimental channel

    NASA Astrophysics Data System (ADS)

    Bennett, Sean J.; Ghaneeizad, S. Mohammad; Gallisdorfer, Michael S.; Cai, Donghua; Atkinson, Joseph F.; Simon, Andrew; Langendoen, Eddy J.

    2015-11-01

    Engineered log jams (ELJs) have become attractive alternatives for river restoration and bank stabilization programs. Yet the effects of ELJs on turbulent flow and the fluid forces acting on the ELJs are not well known, and such information could inform design criteria. In this study, a fixed-bed physical model was constructed to assess the introduction of ELJs along the Big Sioux River, SD. Two ELJ types were examined, referred to as ELJ-1 and ELJ-2. Both types were deflector jams, where ELJ-1 was rectangular and ELJ-2 was triangular, and oriented with one side attached to the channel bank. They were deployed either as single structures or in groups of two or three on the same side of the channel and at different separation distances. Results show that (1) time-mean and turbulent velocities and bed shear stresses were measurably altered near the ELJ, but spatially averaged flow just upstream and downstream of the structure was unaffected; (2) streamwise drag forces measured for the ELJs were significantly larger than the transverse forces, and the derived drag coefficients for the single structures were 2.72 ± 0.19 for ELJ-1 and 1.60 ± 0.37 for ELJ-2; and (3) the presence of an upstream structure created a near-bank wake region that extended a distance of more than 30 flow depths downstream, which greatly reduced drag forces and drag coefficients observed for the downstream structure by as much as 80%. These observations are further evidence of the efficacy of ELJs in providing near-structure scour pool development and bank protection downstream, and they can be used to inform and assess the design of ELJs for use in river restoration and bank stabilization projects.

  18. Emissions of polycyclic aromatic hydrocarbons from fluidized and fixed bed incinerators disposing petrochemical industrial biological sludge.

    PubMed

    Wang, Lin-Chi; Lin, Long-Full; Lai, Soon-Onn

    2009-08-30

    This study investigated the emissions of polycyclic aromatic hydrocarbons (PAHs) from two fluidized bed incinerators (FLBI_A and FLBI_B) and one fixed bed incinerator (FIBI) disposing biological sludge generated from the petrochemical industries in Taiwan. The results of 21 individual PAHs (including low (LM-PAHs), middle (MM-PAHs) and high molecular weight PAHs (HM-PAHs)) were reported. The LM-PAHs mainly dominated the total-PAHs in the stack flue gases, whereas the LM- and HM-PAHs dominated the total-PAHs in the bottom fly, fly ash and WSB effluent. Due to high carcinogenic potencies (=total-BaP(eq) concentrations) in the bottom ash (195 ng g(-1)) and WSB effluent (20,600 ng L(-1)) of the FIBI, cautious should be taken in treating them to avoid second contamination. Lower combustion efficiency and elevated fuel/feedstock (F/W) ratio for the FIBI led to the highest total emission factor of total-PAHs (38,400 microg kg(-1)). Lower total-PAH removal efficiencies of wet scrubber (WSB) (0.837-5.89%), cyclone (0.109-0.255%) and electrostatic precipitator (ESP) (0.032%) than those reported elsewhere resulted in high fraction in PAH contributions from the stack flue gases. Lower total-PAH emission factor was found for FLBI_A (2380 microg kg(-1) biological sludge) with higher combustion efficiency compared to those for FLBI_B (11,500 microg kg(-1)) and FIBI (38,400 microg kg(-1) biological sludge), implying that combustion efficiency plays a vital role in PAH emissions.

  19. Porous filtering media comparison through wet and dry sampling of fixed bed gasification products

    NASA Astrophysics Data System (ADS)

    Allesina, G.; Pedrazzi, S.; Montermini, L.; Giorgini, L.; Bortolani, G.; Tartarini, P.

    2014-11-01

    The syngas produced by fixed bed gasifiers contains high quantities of particulate and tars. This issue, together with its high temperature, avoids its direct exploitation without a proper cleaning and cooling process. In fact, when the syngas produced by gasification is used in an Internal Combustion engine (IC), the higher the content of tars and particulate, the higher the risk to damage the engine is. If these compounds are not properly removed, the engine may fail to run. A way to avoid engine fails is to intensify the maintenance schedule, but these stops will reduce the system profitability. From a clean syngas does not only follow higher performance of the generator, but also less pollutants in the atmosphere. When is not possible to work on the gasification reactions, the filter plays the most important role in the engine safeguard process. This work is aimed at developing and comparing different porous filters for biomass gasifiers power plants. A drum filter was developed and tested filling it with different filtering media available on the market. As a starting point, the filter was implemented in a Power Pallet 10 kW gasifier produced by the California-based company "ALL Power Labs". The original filter was replaced with different porous biomasses, such as woodchips and corn cobs. Finally, a synthetic zeolites medium was tested and compared with the biological media previously used. The Tar Sampling Protocol (TSP) and a modified "dry" method using the Silica Gel material were applied to evaluate the tars, particulate and water amount in the syngas after the filtration process. Advantages and disadvantages of every filtering media chosen were reported and discussed.

  20. Anaerobic-aerobic sequencing bioreactors improve energy efficiency for treatment of personal care product industry wastes.

    PubMed

    Ahammad, S Z; Bereslawski, J L; Dolfing, J; Mota, C; Graham, D W

    2013-07-01

    Personal care product (PCP) industry liquid wastes contain shampoo residues, which are usually treated by aerobic activated sludge (AS). Unfortunately, AS is expensive for PCP wastes because of high aeration and energy demands, whereas potentially energy-positive anaerobic designs cannot meet effluent targets. Therefore, combined anaerobic-aerobic systems may be the best solution. Seven treatment systems were assessed in terms of energy and treatment performance for shampoo wastes, including one aerobic, three anaerobic (HUASB, AHR and AnCSTR) and three anaerobic-aerobic reactor designs. COD removals were highest in the HUASB-aerobic (87.9 ± 0.4%) and AHR-aerobic (86.8±0.5%) systems, which used 69.2% and 62.5% less energy than aerobic AS. However, actual methane production rates were low relative to theoretical in the UASB and AHR units (∼10% methane/COD removed) compared with the AnCSTR unit (∼70%). Anaerobic-aerobic sequence reactors show promise for treating shampoo wastes, but optimal designs depend upon whether methane production or COD removal is most important to operations.

  1. Co-pyrolysis of pine sawdust and lignite in a thermogravimetric analyzer and a fixed-bed reactor.

    PubMed

    Song, Yuyao; Tahmasebi, Arash; Yu, Jianglong

    2014-12-01

    Co-pyrolysis characteristics of lignite and pine sawdust were studied in a TGA and a fixed-bed reactor. The effects of pyrolysis temperature and blending ratio on the yield and composition of pyrolysis products (gas, tar, and char) were investigated. TGA experiments showed that pine sawdust decomposition took place at lower temperatures compared to lignite. With increasing the pine sawdust content in the blend, the DTG peaks shifted towards lower temperatures due to synergetic effect. In fixed-bed experiments, the synergetic effect increased the yield of volatile matter compared to the calculated values. The major gases released at low temperatures were CO2 and CO. However, hydrogen was the primary gaseous product at higher temperatures. During co-pyrolysis, concentrations of benzene, naphthalene, and hydrocarbons in the tar decreased, accompanied by an increase in phenols and guaiacol concentrations. With increasing pyrolysis temperature, the OH, aliphatic CH, CO, and CO functional groups in char decomposed substantially.

  2. Fixed-bed gasification research using US coals. Volume 8. Gasification of River King Illinois No. 6 bituminous coal

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-05-01

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report is the eighth volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This specific report describes the gasification of River King Illinois No. 6 bituminous coal. The period of gasification test was July 28 to August 19, 1983. 6 refs., 23 figs., 25 tabs.

  3. Fixed-bed gasification research using US coals. Volume 12. Gasification of Absaloka/Robinson subbituminous coal

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-05-01

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial particpants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report is the twelfth volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. this specific reports describes the gasification of Absaloka/Robinson subbituminous coal. This volume covers the test period June 18, 1984 to June 30, 1984. 4 refs., 20 figs., 18 tabs.

  4. Fixed-bed gasification research using US coals. Volume 17. Gasification and liquids recovery of four US coals

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-12-01

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and government agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) group. This report is the seventeenth in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This report describes the gasification and pyrolysis liquids recovery test for four different coals: Illinois No. 6, SUFCO, Indianhead lignite, and Hiawatha. This test series spanned from July 15, 1985, through July 28, 1985. 4 refs., 16 figs., 19 tabs.

  5. Fixed-bed gasification research using US coals. Volume 16. Gasification of 2-inch Minnesota peat sods

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-10-01

    A single, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scubber used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and government agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) group. This report is the sixteenth volume in a series of reports describing the atmospheric pressure, fixed-bed gasification of US coals. This specific test report describes the gasification of two-inch Minnesota peat sods, which began on June 24, 1985 and was completed on June 27, 1985. 4 refs., 18 figs., 14 tabs.

  6. Design and fabrication of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolytic oil production in Bangladesh

    NASA Astrophysics Data System (ADS)

    Aziz, Mohammad Abdul; Al-khulaidi, Rami Ali; Rashid, MM; Islam, M. R.; Rashid, MAN

    2017-03-01

    In this research, a development and performance test of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolysis oil production was successfully completed. The characteristics of the pyrolysis oil were compared to other experimental results. A solid horizontal condenser, a burner for furnace heating and a reactor shield were designed. Due to the pilot scale pyrolytic oil production encountered numerous problems during the plant’s operation. This fixed-bed batch type pyrolysis reactor method will demonstrate the energy saving concept of solid waste tire by creating energy stability. From this experiment, product yields (wt. %) for liquid or pyrolytic oil were 49%, char 38.3 % and pyrolytic gas 12.7% with an operation running time of 185 minutes.

  7. Production of phenol-rich bio-oil during catalytic fixed-bed and microwave pyrolysis of palm kernel shell.

    PubMed

    Omoriyekomwan, Joy Esohe; Tahmasebi, Arash; Yu, Jianglong

    2016-05-01

    Catalytic fixed-bed and microwave pyrolysis of palm kernel shell using activated carbon (AC) and lignite char (LC) as catalysts and microwave receptors are investigated. The effects of process parameters including temperature and biomass:catalyst ratio on the yield and composition of pyrolysis products were studied. The addition of catalyst increased the bio-oil yield, but decreased the selectivity of phenol in fixed-bed. Catalytic microwave pyrolysis of PKS significantly enhanced the selectivity of phenol production. The highest concentration of phenol in bio-oil of 64.58 %(area) and total phenolics concentration of 71.24 %(area) were obtained at 500°C using AC. Fourier transform infrared spectroscopy (FTIR) results indicated that concentration of OH, CH, CO and CO functional groups in char samples decreased after pyrolysis. Scanning electron microscopy (SEM) analysis clearly indicated the development of liquid phase in biomass particles during microwave pyrolysis, and the mechanism is also discussed.

  8. Fixed bed sorption of phosphorus from wastewater using iron oxide-based media derived from acid mine drainage

    USGS Publications Warehouse

    Sibrell, Philip L.; Tucker, T.W.

    2012-01-01

    Phosphorus (P) releases to the environment have been implicated in the eutrophication of important water bodies worldwide. Current technology for the removal of P from wastewaters consists of treatment with aluminum (Al) or iron (Fe) salts, but is expensive. The neutralization of acid mine drainage (AMD) generates sludge rich in Fe and Al oxides that has hitherto been considered a waste product, but these sludges could serve as an economical adsorption media for the removal of P from wastewaters. Therefore, we have evaluated an AMD-derived media as a sorbent for P in fixed bed sorption systems. The homogenous surface diffusion model (HSDM) was used to analyze fixed bed test data and to determine the value of related sorption parameters. The surface diffusion modulus Ed was found to be a useful predictor of sorption kinetics. Values of Ed < 0.2 were associated with early breakthrough of P, while more desirable S-shaped breakthrough curves resulted when 0.2 < Ed < 0.5. Computer simulations of the fixed bed process with the HSDM confirmed that if Ed was known, the shape of the breakthrough curve could be calculated. The surface diffusion coefficient D s was a critical factor in the calculation of Ed and could be estimated based on the sorption test conditions such as media characteristics, and influent flow rate and concentration. Optimal test results were obtained with a relatively small media particle size (average particle radius 0.028 cm) and resulted in 96 % removal of P from the influent over 46 days of continuous operation. These results indicate that fixed bed sorption of P would be a feasible option for the utilization of AMD residues, thus helping to decrease AMD treatment costs while at the same time ameliorating the impacts of P contamination.

  9. Calculation of the fixed bed coal gasification regimes by the use of thermodynamic model with macrokinetic constraints

    NASA Astrophysics Data System (ADS)

    Donskoi, I. G.; Keiko, A. V.; Kozlov, A. N.; Svishchev, D. A.; Shamanskii, V. A.

    2013-12-01

    We discuss an equilibrium model of a fixed-bed solid fuel gasification process that takes into account macrokinetic constraints imposed on the rates of heterophase processes and allows the pyrolysis and gasification processes to be described in a fairly simple manner with the use of thermal analysis data. The results of calculations are compared with the measured parameters characterizing the Azeisk coal steam-air gasification process that were obtained in experiments on a laboratory setup.

  10. Enhanced removal of sulfonamide antibiotics by KOH-activated anthracite coal: Batch and fixed-bed studies.

    PubMed

    Zuo, Linzi; Ai, Jing; Fu, Heyun; Chen, Wei; Zheng, Shourong; Xu, Zhaoyi; Zhu, Dongqiang

    2016-04-01

    The presence of sulfonamide antibiotics in aquatic environments poses potential risks to human health and ecosystems. In the present study, a highly porous activated carbon was prepared by KOH activation of an anthracite coal (Anth-KOH), and its adsorption properties toward two sulfonamides (sulfamethoxazole and sulfapyridine) and three smaller-sized monoaromatics (phenol, 4-nitrophenol and 1,3-dinitrobenzene) were examined in both batch and fixed-bed adsorption experiments to probe the interplay between adsorbate molecular size and adsorbent pore structure. A commercial powder microporous activated carbon (PAC) and a commercial mesoporous carbon (CMK-3) possessing distinct pore properties were included as comparative adsorbents. Among the three adsorbents Anth-KOH exhibited the largest adsorption capacities for all test adsorbates (especially the two sulfonamides) in both batch mode and fixed-bed mode. After being normalized by the adsorbent surface area, the batch adsorption isotherms of sulfonamides on PAC and Anth-KOH were displaced upward relative to the isotherms on CMK-3, likely due to the micropore-filling effect facilitated by the microporosity of adsorbents. In the fixed-bed mode, the surface area-normalized adsorption capacities of Anth-KOH for sulfonamides were close to that of CMK-3, and higher than that of PAC. The irregular, closed micropores of PAC might impede the diffusion of the relatively large-sized sulfonamide molecules and in turn led to lowered fixed-bed adsorption capacities. The overall superior adsorption of sulfonamides on Anth-KOH can be attributed to its large specific surface area (2514 m(2)/g), high pore volume (1.23 cm(3)/g) and large micropore sizes (centered at 2.0 nm). These findings imply that KOH-activated anthracite coal is a promising adsorbent for the removal of sulfonamide antibiotics from aqueous solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Atomic layer deposition on porous powders with in situ gravimetric monitoring in a modular fixed bed reactor setup.

    PubMed

    Strempel, V E; Naumann d'Alnoncourt, R; Driess, M; Rosowski, F

    2017-07-01

    A modular setup for Atomic Layer Deposition (ALD) on high-surface powder substrates in fixed bed reactors with a gravimetric in situ monitoring was developed. The design and operation are described in detail. An integrated magnetically suspended balance records mass changes during ALD. The highly versatile setup consists of three modular main units: a dosing unit, a reactor unit, and a downstream unit. The reactor unit includes the balance, a large fixed bed reactor, and a quartz crystal microbalance. The dosing unit is equipped with a complex manifold to deliver gases and gaseous reagents including three different ALD precursors, five oxidizing or reducing agents, and two purge gas lines. The system employs reactor temperatures and pressures in the range of 25-600 °C and 10(-3) to 1 bar, respectively. Typically, powder batches between 100 mg and 50 g can be coated. The capabilities of the setup are demonstrated by coating mesoporous SiO2 powder with a thin AlOx (submono) layer using three cycles with trimethylaluminium and H2O. The self-limiting nature of the deposition has been verified with the in situ gravimetric monitoring and full saturation curves are presented. The process parameters were used for a scale-up in a large fixed bed reactor. The samples were analyzed with established analytics such as X-ray diffraction, N2 adsorption, transmission electron microscopy, and inductively coupled plasma optical emission spectrometry.

  12. Atomic layer deposition on porous powders with in situ gravimetric monitoring in a modular fixed bed reactor setup

    NASA Astrophysics Data System (ADS)

    Strempel, V. E.; Naumann d'Alnoncourt, R.; Driess, M.; Rosowski, F.

    2017-07-01

    A modular setup for Atomic Layer Deposition (ALD) on high-surface powder substrates in fixed bed reactors with a gravimetric in situ monitoring was developed. The design and operation are described in detail. An integrated magnetically suspended balance records mass changes during ALD. The highly versatile setup consists of three modular main units: a dosing unit, a reactor unit, and a downstream unit. The reactor unit includes the balance, a large fixed bed reactor, and a quartz crystal microbalance. The dosing unit is equipped with a complex manifold to deliver gases and gaseous reagents including three different ALD precursors, five oxidizing or reducing agents, and two purge gas lines. The system employs reactor temperatures and pressures in the range of 25-600 °C and 10-3 to 1 bar, respectively. Typically, powder batches between 100 mg and 50 g can be coated. The capabilities of the setup are demonstrated by coating mesoporous SiO2 powder with a thin AlOx (submono) layer using three cycles with trimethylaluminium and H2O. The self-limiting nature of the deposition has been verified with the in situ gravimetric monitoring and full saturation curves are presented. The process parameters were used for a scale-up in a large fixed bed reactor. The samples were analyzed with established analytics such as X-ray diffraction, N2 adsorption, transmission electron microscopy, and inductively coupled plasma optical emission spectrometry.

  13. Biodegradation of Phenol in Synthetic Wastewater Using a Fixed Bed Reactor With up Flow Sludge Blanket Filtration (FUSBF)

    PubMed Central

    Ghannadzadeh, Mohammad-Javad; Jonidi-Jafari, Ahmad; Rezaee, Abbas; Soltani, Reza Darvishi Cheshmeh

    2015-01-01

    In the present study, the removal of phenol from synthetic wastewater was evaluated in a fixed bed reactor with up flow sludge blanket filtration (FUSBF) in comparison with a typical USBF system. At hydraulic retention time (HRT) of 24 hours and solid retention time (SRT) of 20 day, the effect of initial concentration of phenol (260-1020 mg/L) on phenol and chemical oxygen demand (COD) removal efficiency (%) was investigated in both systems. The effect of the presence of fixed bed was determined throughout the operational period. The results showed that the FUSBF system had a better ability than the typical USBF system in terms of phenol and COD removal. The average phenol and COD removal at phenol concentration of 312 mg/L was 97.52% and 92.82% for the FUSBF system and 92.80% and 82.18% for the typical USBF system, respectively. At HRT of 24 h and organic loading rate (OLR) of 30 g/m-3.h-1, the amount of phenol removal was 82.1%. At OLR of 30 g/m-3.h-1, role of fixed bed in phenol and COD removal was 25.01% and 29.3%, respectively, overall, the FUSBF system has a higher efficiency and ability than that of typical USBF and can be used for the purification of industrial wastewater containing refractory organic compounds such as phenol. PMID:26153212

  14. Continuous biodiesel production in a fixed bed reactor packed with anion-exchange resin as heterogeneous catalyst.

    PubMed

    Ren, Yanbiao; He, Benqiao; Yan, Feng; Wang, Hong; Cheng, Yu; Lin, Ligang; Feng, Yaohui; Li, Jianxin

    2012-06-01

    A continuous biodiesel production from the transesterification of soybean oil with methanol was investigated in a fixed bed reactor packed with D261 anion-exchange resin as a heterogeneous catalyst. The conversion to biodiesel achieved 95.2% within a residence time 56 min under the conditions: reaction temperature of 323.15K, n-hexane/soybean oil weight rate of 0.5, methanol/soybean oil molar ratio of 9:1 and feed flow rate of 1.2 ml/min. The resin can be regenerated in-situ and restored to the original activity to achieve continuous production after the resin deactivation. The product obtained was mainly composed of methyl esters. No glycerol in the product was detected due to the resin adsorbing glycerol in the fixed bed, which solved the issue of glycerol separation from biodiesel. It is believed that the fixed bed reactor with D261 has a potential commercial application in the transesterification of triglyceride. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. A proposed taxonomy of anaerobic fungi (class neocallimastigomycetes) suitable for large-scale sequence-based community structure analysis.

    PubMed

    Kittelmann, Sandra; Naylor, Graham E; Koolaard, John P; Janssen, Peter H

    2012-01-01

    Anaerobic fungi are key players in the breakdown of fibrous plant material in the rumen, but not much is known about the composition and stability of fungal communities in ruminants. We analyzed anaerobic fungi in 53 rumen samples from farmed sheep (4 different flocks), cattle, and deer feeding on a variety of diets. Denaturing gradient gel electrophoresis fingerprinting of the internal transcribed spacer 1 (ITS1) region of the rrn operon revealed a high diversity of anaerobic fungal phylotypes across all samples. Clone libraries of the ITS1 region were constructed from DNA from 11 rumen samples that had distinctly different fungal communities. A total of 417 new sequences were generated to expand the number and diversity of ITS1 sequences available. Major phylogenetic groups of anaerobic fungi in New Zealand ruminants belonged to the genera Piromyces, Neocallimastix, Caecomyces and Orpinomyces. In addition, sequences forming four novel clades were obtained, which may represent so far undetected genera or species of anaerobic fungi. We propose a revised phylogeny and pragmatic taxonomy for anaerobic fungi, which was tested and proved suitable for analysis of datasets stemming from high-throughput next-generation sequencing methods. Comparing our revised taxonomy to the taxonomic assignment of sequences deposited in the GenBank database, we believe that >29% of ITS1 sequences derived from anaerobic fungal isolates or clones are misnamed at the genus level.

  16. Draft genome sequence of a strictly anaerobic dichloromethane-degrading bacterium

    SciTech Connect

    Kleindienst, Sara; Higgins, Steven A.; Tsementzi, Despina; Konstantinidis, Konstantinos T.; Mack, E. Erin; Loffler, Frank E.

    2016-03-03

    Here, an anaerobic, dichloromethane-degrading bacterium affiliated with novel Peptococcaceae was maintained in a microbial consortium. The organism originated from pristine freshwater sediment collected from Rio Mameyes in Luquillo, Puerto Rico, in October 2009 (latitude 18°21'43.9", longitude –65°46'8.4"). The draft genome sequence is 2.1 Mb and has a G+C content of 43.5%.

  17. Draft genome sequence of a strictly anaerobic dichloromethane-degrading bacterium

    DOE PAGES

    Kleindienst, Sara; Higgins, Steven A.; Tsementzi, Despina; ...

    2016-03-03

    Here, an anaerobic, dichloromethane-degrading bacterium affiliated with novel Peptococcaceae was maintained in a microbial consortium. The organism originated from pristine freshwater sediment collected from Rio Mameyes in Luquillo, Puerto Rico, in October 2009 (latitude 18°21'43.9", longitude –65°46'8.4"). The draft genome sequence is 2.1 Mb and has a G+C content of 43.5%.

  18. Effect of bone on the pyrolysis product distribution and composition in a fixed bed reactor

    NASA Astrophysics Data System (ADS)

    Alhassan, M.; Andresen, J. M.

    2012-04-01

    Co-pyrolysis of Biomass including Pistachio shell (PS), Pine wood (PW) and Wheat Straw (WS) with Bone matter (BM) have been investigated to determine the effect of bone on the quality of bio-char and bio-oil produced. The aim of this study is to generate stable and nitrogen enriched bio-char that can act as fertilizer while at the same time optimizes the chemical stability of the char to act as a Carbon Capture and Storage system (CCS) and co-produce high quality oils for renewable energy generation. To achieve this, the present study has focused on the influence of bone matter addition from 0wt% to 25wt% to the biomasses in a fixed bed pyrolysis reactor at 3000C. The analysis of the char products shows that the addition of bone to the biomass increased their char yields up to 10wt% addition. Higher addition was found to reduce the overall char yield from the biomass. At 10wt% bone addition, the carbon, hydrogen, and nitrogen content, and the gross calorific value of the chars were increased by 7wt%, 29wt%, 163wt% and 19Mj/kg, for Wheat straw, 62wt%, 46wt%, 135wt%, 110Mj/kg for Pine wood and 7wt%, 76wt%, 42wt% and 33Mj/kg for Pistachio shells. The oxygen content of the Wheat straw, Pistachio shells and pine wood mixed with 10wt% BM decreased by 28wt%, 21wt%, and 93wt%, respectively. The bio-oil yield increased for the bone addition up to 5%wt% for all the samples, its energy value and concentration of its major chemical components was improved for fuel and pharmaceutical use. Port experiment has shown that plant grown on soil amended with the bio-char produced gave higher yield as compared to that from un-amended soil. Comparison between the three biomasses investigated showed similar pattern of change. Hence it can be concluded that at optimum addition of bone to the biomass, bio-chars and oil yield could be optimized for soil amendment, energy production, while retaining carbon for sequestration.

  19. Drop Breakup in Fixed Bed Flows as Model Stochastic Flow Fields

    NASA Technical Reports Server (NTRS)

    Shaqfeh, Eric S. G.; Mosler, Alisa B.; Patel, Prateek

    1999-01-01

    We examine drop breakup in a class of stochastic flow fields as a model for the flow through fixed fiber beds and to elucidate the general mechanisms whereby drops breakup in disordered, Lagrangian unsteady flows. Our study consists of two parallel streams of investigation. First, large scale numerical simulations of drop breakup in a class of anisotropic Gaussian fields will be presented. These fields are generated spectrally and have been shown in a previous publication to be exact representations of the flow in a dilute disordered bed of fibers if close interactions between the fibers and the drops are dynamically unimportant. In these simulations the drop shape is represented by second and third order small deformation theories which have been shown to be excellent for the prediction of drop breakup in steady strong flows. We show via these simulations that the mechanisms of drop breakup in these flows are quite different than in steady flows. The predominant mechanism of breakup appears to be very short lived twist breakups. Moreover, the occurrence of breakup events is poorly predicted by either the strength of the local flow in which the drop finds itself at breakup, or the degree of deformation that the drop achieves prior to breakup. It is suggested that a correlation function of both is necessary to be predictive of breakup events. In the second part of our research experiments are presented where the drop deformation and breakup in PDMS/polyisobutylene emulsions is considered. We consider very dilute emulsions such that coalescence is unimportant. The flows considered are simple shear and the flow through fixed fiber beds. Turbidity, small angle light scattering, dichroism and microscopy are used to interrogate the drop deformation process in both flows. It is demonstrated that breakup at very low capillary numbers occurs in both flows but larger drop deformation occurs in the fixed bed flow. Moreover, it is witnessed that breakup in the bed occurs

  20. Hydrodynamics of concordant and discordant fixed bed open-channel confluences

    NASA Astrophysics Data System (ADS)

    Birjukova Canelas, Olga; Lage Ferreira, Rui Miguel; Heleno Cardoso, António

    2017-04-01

    The detailed characterization of the flow field in river confluences constitutes a relevant step towards the understanding of the hydro-morpho-dynamics of these key zones of the fluvial system. With a few exceptions, existing works on this topic covered concordant bed scenarios, meaning that both confluent channels had the same elevation. This laboratory study aims to contribute to a detailed three-dimensional characterization of the flow field at a fixed bed confluence, as well as to shed light on how bed elevation discordance modifies the flow patterns of the converging flows. While the junction angle and the discharge ratio were kept fixed, two scenarios were studied on the basis of detailed water level and 3D ADV measurements at the denser mesh ever. The internal flow structure of the concordant bed scenario mostly complied with the classical conceptual models. A relevant difference concerns the size of the stagnation zone, much smaller close to the bed of the discordant bed confluence. A more significant difference is a horizontal flow structure, not previously identified in the literature, characterized by strong streamwise mean vorticity and strong secondary motion. It is observed for the discordant bed case, occurring along the inner wall of the main channel and downstream the junction corner. This structure is spatially well-correlated to a pronounced imbalance of cross-stream and vertical normal Reynolds stresses. This highlights the role of Reynolds stress anisotropy (RSA) that is generated in the shear layers than accompany the entrance of the tributary flow. Since this structure is not present in the concordant case, where RSA is also evident, it is argued that convective effects should also play a role in its formation, presumably due to deflection of the flow in the main channel by the tributary. The newly identified secondary motion should, thus, be a combination of Prandtĺs second kind and Prandtĺs first kind of secondary flow. The relative

  1. Quantification of genes and gene transcripts for microbial perchlorate reduction in fixed-bed bioreactors.

    PubMed

    De Long, S K; Li, X; Bae, S; Brown, J C; Raskin, L; Kinney, K A; Kirisits, M J

    2012-03-01

    Optimization of full-scale, biological perchlorate treatment processes for drinking water would benefit from knowledge of the location and quantity of perchlorate-reducing bacteria (PRB) and expression of perchlorate-related genes in bioreactors. The aim of this study was to quantify perchlorate removal and perchlorate-related genes (pcrA and cld) and their transcripts in bioreactors and to determine whether these genes or transcripts could serve as useful biomarkers for perchlorate treatment processes. Quantitative PCR (qPCR) assays targeting pcrA and cld were applied to two pilot-scale, fixed-bed bioreactors treating perchlorate-contaminated groundwater. pcrA and cld genes per microgram of DNA were two- to threefold higher and three- to fourfold higher, respectively, in the bioreactor showing superior perchlorate-removal performance. In a laboratory-scale bioreactor, quantities of pcrA and cld genes and transcripts were compared under two distinct performance conditions (c.60 and 20% perchlorate removal) for a 5-min empty bed contact time. cld genes per microgram of DNA were approximately threefold higher and cld transcripts per microgram of RNA were approximately sixfold higher under the higher perchlorate-removal condition. No differences in pcrA genes or transcripts per microgram of DNA or RNA, respectively, were detected between the c.60 and 20% perchlorate-removal conditions, possibly because these assays did not accurately quantify pcrA genes and transcripts in the mixed culture present. Quantities of cld genes and transcripts per microgram of DNA and RNA, respectively, were found to be higher when perchlorate removal was higher. However, quantities of pcrA and cld genes or transcripts were not found to directly correlate with perchlorate-removal rates. To our knowledge, this study represents the first application of qPCR assays to quantify perchlorate-related genes and transcripts in continuous-flow bioreactors. The results indicate that cld gene and

  2. Identification of the regulatory sequence of anaerobically expressed locus aeg-46.5.

    PubMed Central

    Choe, M; Reznikoff, W S

    1993-01-01

    A newly identified anaerobically expressed locus, aeg-46.5, which is located at min 46.5 on Escherichia coli linkage map, was cloned and analyzed. The phenotype of this gene was studied by using a lacZ operon fusion. aeg-46.5 is induced anaerobically in the presence of nitrate in wild-type and narL cells. It is repressed by the narL gene product, as it showed derepressed anaerobic expression in narL mutant cells. We postulate that aeg-46.5 is subject to multiple regulatory systems, activation as a result of anaerobiosis, narL-independent nitrate-dependent activation, and narL-mediated repression. The regulatory region of aeg-46.5 was identified. A 304-bp DNA sequence which includes the regulatory elements was obtained, and the 5' end of aeg-46.5 mRNA was identified. It was verified that the anaerobic regulation of aeg-46.5 expression is controlled on the transcriptional level. Computer analysis predicted possible control sites for the NarL and FNR proteins. The proposed NarL site was found in a perfect-symmetry element. The aeg-46.5 regulatory elements are adjacent to, but divergent from, those of the eco gene. Images PMID:8432709

  3. Genome sequence of the polysaccharide-degrading, thermophilic anaerobe Spirochaeta thermophila DSM 6192.

    PubMed

    Angelov, Angel; Liebl, Susanne; Ballschmiter, Meike; Bömeke, Mechthild; Lehmann, Rüdiger; Liesegang, Heiko; Daniel, Rolf; Liebl, Wolfgang

    2010-12-01

    Spirochaeta thermophila is a thermophilic, free-living anaerobe that is able to degrade various α- and β-linked sugar polymers, including cellulose. We report here the complete genome sequence of S. thermophila DSM 6192, which is the first genome sequence of a thermophilic, free-living member of the Spirochaetes phylum. The genome data reveal a high density of genes encoding enzymes from more than 30 glycoside hydrolase families, a noncellulosomal enzyme system for (hemi)cellulose degradation, and indicate the presence of a novel carbohydrate-binding module.

  4. Genome Sequence of the Polysaccharide-Degrading, Thermophilic Anaerobe Spirochaeta thermophila DSM 6192▿

    PubMed Central

    Angelov, Angel; Liebl, Susanne; Ballschmiter, Meike; Bömeke, Mechthild; Lehmann, Rüdiger; Liesegang, Heiko; Daniel, Rolf; Liebl, Wolfgang

    2010-01-01

    Spirochaeta thermophila is a thermophilic, free-living anaerobe that is able to degrade various α- and β-linked sugar polymers, including cellulose. We report here the complete genome sequence of S. thermophila DSM 6192, which is the first genome sequence of a thermophilic, free-living member of the Spirochaetes phylum. The genome data reveal a high density of genes encoding enzymes from more than 30 glycoside hydrolase families, a noncellulosomal enzyme system for (hemi)cellulose degradation, and indicate the presence of a novel carbohydrate-binding module. PMID:20935097

  5. Non-oxidative coupling of methane catalysed by supported tungsten hydride onto alumina and silica-alumina in classical and H2 permeable membrane fixed-bed reactors.

    PubMed

    Szeto, K C; Norsic, S; Hardou, L; Le Roux, E; Chakka, S; Thivolle-Cazat, J; Baudouin, A; Papaioannou, C; Basset, J-M; Taoufik, M

    2010-06-14

    Non-oxidative coupling of methane with high selectivity into ethane (>99% among hydrocarbon) in a classical fixed-bed reactor catalysed by SiO(2)-Al(2)O(3) or gamma-Al(2)O(3) supported tungsten hydride is presented. Continuous hydrogen separation, using a Pd-Ag membrane in a fixed-bed reactor, led to methane coupling far beyond the thermodynamic equilibrium conversion.

  6. Microbial community analysis of swine wastewater anaerobic lagoons by next-generation DNA sequencing.

    PubMed

    Ducey, Thomas F; Hunt, Patrick G

    2013-06-01

    Anaerobic lagoons are a standard practice for the treatment of swine wastewater. This practice relies heavily on microbiological processes to reduce concentrated organic material and nutrients. Despite this reliance on microbiological processes, research has only recently begun to identify and enumerate the myriad and complex interactions that occur in this microbial ecosystem. To further this line of study, we utilized a next-generation sequencing (NGS) technology to gain a deeper insight into the microbial communities along the water column of four anaerobic swine wastewater lagoons. Analysis of roughly one million 16S rDNA sequences revealed a predominance of operational taxonomic units (OTUs) classified as belonging to the phyla Firmicutes (54.1%) and Proteobacteria (15.8%). At the family level, 33 bacterial families were found in all 12 lagoon sites and accounted for between 30% and 50% of each lagoon's OTUs. Analysis by nonmetric multidimensional scaling (NMS) revealed that TKN, COD, ORP, TSS, and DO were the major environmental variables in affecting microbial community structure. Overall, 839 individual genera were classified, with 223 found in all four lagoons. An additional 321 genera were identified in sole lagoons. The top 25 genera accounted for approximately 20% of the OTUs identified in the study, and the low abundances of most of the genera suggests that most OTUs are present at low levels. Overall, these results demonstrate that anaerobic lagoons have distinct microbial communities which are strongly controlled by the environmental conditions present in each individual lagoon. Published by Elsevier Ltd.

  7. Biogas Production from Brewer’s Yeast Using an Anaerobic Sequencing Batch Reactor

    PubMed Central

    2017-01-01

    Summary Renewable energy sources are becoming increasingly important in the beverage and food industries. In the brewing industry, a significant percentage of the used raw materials finishes the process as secondary resource or waste. The research on the anaerobic digestion of brewer’s yeast has been scarce until recent years. One of the reasons for this is its use as a secondary resource in the food industry and as cattle feed. Additionally, market value of brewer’s yeast is higher than its energy value. Due to the increase of energy prices, brewer’s yeast has become of interest as energy substrate despite its difficult degradability in anaerobic conditions. The anaerobic co-digestion of brewer’s yeast and anaerobically treated brewery wastewater was studied using a pilot-scale anaerobic sequencing batch reactor (ASBR) seeded with granular biomass. The experiments showed very good and stable operation with an organic loading rate of up to 8.0 kg/(m3·day), and with a maximum achieved organic loading rate of 13.6 kg/(m3·day) in a single cycle. A specific biogas productivity of over 0.430 m3/kg of the total chemical oxygen demand (COD) inserted, and total COD removal efficiencies of over 90% were achieved. This study suggests that the brewer’s yeast can be successfully digested in an ASBR without adverse effects on the biogas production from brewer’s yeast/wastewater mixtures of up to 8% (by volume). By using the brewer’s yeast in the ASBR process, the biogas production from brewery wastewater could be increased by 50%. PMID:28867948

  8. Biogas Production from Brewer's Yeast Using an Anaerobic Sequencing Batch Reactor.

    PubMed

    Zupančič, Gregor Drago; Panjičko, Mario; Zelić, Bruno

    2017-06-01

    Renewable energy sources are becoming increasingly important in the beverage and food industries. In the brewing industry, a significant percentage of the used raw materials finishes the process as secondary resource or waste. The research on the anaerobic digestion of brewer's yeast has been scarce until recent years. One of the reasons for this is its use as a secondary resource in the food industry and as cattle feed. Additionally, market value of brewer's yeast is higher than its energy value. Due to the increase of energy prices, brewer's yeast has become of interest as energy substrate despite its difficult degradability in anaerobic conditions. The anaerobic co-digestion of brewer's yeast and anaerobically treated brewery wastewater was studied using a pilot-scale anaerobic sequencing batch reactor (ASBR) seeded with granular biomass. The experiments showed very good and stable operation with an organic loading rate of up to 8.0 kg/(m(3)·day), and with a maximum achieved organic loading rate of 13.6 kg/(m(3)·day) in a single cycle. A specific biogas productivity of over 0.430 m(3)/kg of the total chemical oxygen demand (COD) inserted, and total COD removal efficiencies of over 90% were achieved. This study suggests that the brewer's yeast can be successfully digested in an ASBR without adverse effects on the biogas production from brewer's yeast/wastewater mixtures of up to 8% (by volume). By using the brewer's yeast in the ASBR process, the biogas production from brewery wastewater could be increased by 50%.

  9. Pharmaceutical wastewater treatment using an anaerobic/aerobic sequencing batch biofilter.

    PubMed

    Buitrón, Germán; Melgoza, Rosa Maria; Jiménez, Leonardo

    2003-01-01

    The performance of a sequencing batch biofilter integrating anaerobic/aerobic conditions in one tank to treat a pharmaceutical wastewater effluent was studied. A pilot reactor, packed with a porous volcanic stone (puzzolane) was used in the study. The reactor operated as a sequencing batch biofilter, SBB, with reaction times varying for the anaerobic stage from 8 to 24 h and for the aerobic one from 4 to 12 h. The volume of exchange was from 16 to 88%. The pharmaceutical wastewater contained organic chemicals including phenols and o-nitroaniline, a concentration of organic matter that varied from 28,400 to 72,200 mg/L (as total COD), 280 to 605 mg N-NH4/L. and 430 to 650 mg SST/L. In order to acclimatize the microorganisms to the industrial wastewater, the organic load was increased stepwise from 1 to 7.7 kg COD/m3/d. The adequate time was obtained when the removal efficiency of COD reached 80%, or more. Maximal removal loads, associated to high removal efficiencies (95-97% as COD), varied from 4.6 to 5.7 kg COD/m3/d. Under these conditions color removal was 80% as Pt-Co units. Microtox analysis was performed to the wastewater and to the anaerobic and aerobic stages. It was observed that the aerobic stage was the responsible for wastewater detoxification. Results showed that the anaerobic/aerobic SBB was able to treat efficiently initial concentrations of the raw effluent up to 28,400 mg COD/L.

  10. Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed-Bed and Entrained-Flow Reactor

    SciTech Connect

    Buitrago, Paula A.; Morrill, Mike; Lighty, JoAnn S.; Silcox, Geoffrey D.

    2009-06-01

    This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150°C. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and

  11. Biosorption of copper, cobalt and nickel by marine brown alga Sargassum sp. in fixed-bed column.

    PubMed

    Esmaeili, Akbar; Soufi, Samira; Rustaiyan, Abdolhossein; Safaiyan, Shila; Mirian, Simin; Fallahe, Gila; Moazami, Nasrin

    2007-11-01

    The biosorption of copper, cobalt and nickel by marine brown alga Sargassum sp. were investigated in a fixed-bed column (temperature = 30 degrees C; different pH). Langmuir and Freundlich sorption models were used to represent the equilibrium data. The maximum Cu2+ uptake was obtained at pH 4 and the optimum Co2+ and Ni2+ uptake were at pH 7. Different dosage of biosorbent did not have an effect on the results, but the 3.5 and 5 g of biosorbent were shown higher uptake. The metal removal rates were rapid, with about 80% of the total adsorption tacking place within 40 min.

  12. Removal of dioxins and furans from flue gases by non-flammable adsorbents in a fixed bed.

    PubMed

    Fell, H J; Tuczek, M

    1998-01-01

    The presented adsorption--process KOMBISORBON is applied for high efficient off-gas purification, preferably of polychlorinated dioxins and furans from off-gas of incineration plants, which are generated, when these are operated under unfavourable conditions [2]. This off-gas purification process complies with german laws, which limit the concentration of these substances to less than 0.1 ng toxicity equivalents (TE) per cubic metre of gas [1]. The adsorbent, the adsorption process and its plant concept (fixed bed) is described in detail including economics and obtained operation results. Alternative removal technologies are briefly outlined.

  13. Analysis of fixed bed data for the extraction of a rate mechanism for the reaction of hematite with methane

    DOE PAGES

    Breault, Ronald W.; Monazam, Esmail R.

    2015-04-01

    In this study, chemical looping combustion is a promising technology for the capture of CO2 involving redox materials as oxygen carriers. The effects of reduction conditions, namely, temperature and fuel partial pressure on the conversion products are investigated. The experiments were conducted in a laboratory fixed-bed reactor that was operated cyclically with alternating reduction and oxidation periods. Reactions are assumed to occur in the shell surrounding the particle grains with diffusion of oxygen to the surface from the grain core. Activation energies for the shell and core reactions range from 9 to 209 kJ/mol depending on the reaction step.

  14. Analysis of fixed bed data for the extraction of a rate mechanism for the reaction of hematite with methane

    SciTech Connect

    Breault, Ronald W.; Monazam, Esmail R.

    2015-04-01

    In this study, chemical looping combustion is a promising technology for the capture of CO2 involving redox materials as oxygen carriers. The effects of reduction conditions, namely, temperature and fuel partial pressure on the conversion products are investigated. The experiments were conducted in a laboratory fixed-bed reactor that was operated cyclically with alternating reduction and oxidation periods. Reactions are assumed to occur in the shell surrounding the particle grains with diffusion of oxygen to the surface from the grain core. Activation energies for the shell and core reactions range from 9 to 209 kJ/mol depending on the reaction step.

  15. Identity and potential functions of heterotrophic bacterial isolates from a continuous-upflow fixed-bed reactor for denitrification of drinking water with bacterial polyester as source of carbon and electron donor.

    PubMed

    Mergaert, J; Boley, A; Cnockaert, M C; Müller, W R; Swings, J

    2001-07-01

    A collection of 186 heterotrophic bacteria, isolated directly from a continuous-upflow fixed-bed reactor for the denitrification of drinking water, in which poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) granules acted as biofilm carrier, carbon source and electron donor, was studied with regard to taxonomic affiliation and degradation and denitrification characteristics. Two granule samples were taken from a fully operating reactor for enumeration and isolation of heterotrophic bacteria. One sample was drawn from the lower part of the reactor, near the oxic zone, and the other sample from the upper, anoxic part of the fixed bed. Dominant colonies were isolated and the cultures were identified using fatty acid analysis and 16S rDNA sequencing. Their ability to degrade the polymer and 3-hydroxybutyrate and to denitrify in pure culture was assessed. The results show that high numbers of heterotrophic bacteria were present in the biofilms on the polymer granules, with marked differences in taxonomic composition and potential functions between the lower and upper part of the fixed bed. The majority of the isolates were Gram negative bacteria, and most of them were able to reduce nitrate to nitrite or to denitrify, and to utilize 3-hydroxybutyrate as sole source of carbon. Only two groups, one identified as Acidovorax facilis and the other phylogenetically related to Brevundimonas intermedia, could combine denitrification and utilization of poly(3-hydroxybutyrate) (PHB), and were found only in the upper sample. The other groups occurred either in the lower or upper part, or in both samples. They were assigned to Brevundimonas, Pseudomonas, Agrobacterium, Achromobacter, or Phyllobacterium, or were phylogenetically related to Afipia or Stenotrophomonas.

  16. Laboratory-scale anaerobic sequencing batch reactor for treatment of stillage from fruit distillation.

    PubMed

    Rada, Elena Cristina; Ragazzi, Marco; Torretta, Vincenzo

    2013-01-01

    This work describes batch anaerobic digestion tests carried out on stillages, the residue of the distillation process on fruit, in order to contribute to the setting of design parameters for a planned plant. The experimental apparatus was characterized by three reactors, each with a useful volume of 5 L. The different phases of the work carried out were: determining the basic components of the chemical oxygen demand (COD) of the stillages; determining the specific production of biogas; and estimating the rapidly biodegradable COD contained in the stillages. In particular, the main goal of the anaerobic digestion tests on stillages was to measure the parameters of specific gas production (SGP) and gas production rate (GPR) in reactors in which stillages were being digested using ASBR (anaerobic sequencing batch reactor) technology. Runs were developed with increasing concentrations of the feed. The optimal loads for obtaining the maximum SGP and GPR values were 8-9 gCOD L(-1) and 0.9 gCOD g(-1) volatile solids.

  17. Effects of key operational parameters on biohydrogen production via anaerobic fermentation in a sequencing batch reactor.

    PubMed

    Won, S G; Lau, A K

    2011-07-01

    In this study, a series of tests were conducted in a 6L anaerobic sequencing batch reactor (ASBR) to investigate the effect of pH, hydraulic retention time (HRT) and organic loading rate on biohydrogen production at 28°C. Sucrose was used as the main substrate to mimic carbohydrate-rich wastewater and inoculum was prepared from anaerobic digested sludge without pretreatment. The reactor was operated initially with nitrogen sparging to form anaerobic condition. Results showed that methanogens were effectively suppressed. The optimum pH value would vary depending on the HRT. Maximum hydrogen production rate and yield of 3.04 L H(2)/L reactor d and 2.16 mol H(2)/mol hexose respectively were achieved at pH 4.5, HRT 30 h, and OLR 11.0 kg/m(3)d. Two relationships involving the propionic acid/acetic acid ratio and ethanol/acetic acid ratio were derived from the analysis of the metabolites of fermentation. Ethanol/acetic acid ratio of 1.25 was found to be a threshold value for higher hydrogen production.

  18. The genome sequence of the obligately chemolithoautotrophic, facultatively anaerobic bacterium Thiobacillus denitfificans.

    SciTech Connect

    Beller, H R; Larimer, Frank W

    2006-02-01

    The complete genome sequence of Thiobacillus denitrificans ATCC 25259 is the first to become available for an obligately chemolithoautotrophic, sulfur-compound-oxidizing, {beta}-proteobacterium. Analysis of the 2,909,809-bp genome will facilitate our molecular and biochemical understanding of the unusual metabolic repertoire of this bacterium, including its ability to couple denitrification to sulfur-compound oxidation, to catalyze anaerobic, nitrate-dependent oxidation of Fe(II) and U(IV), and to oxidize mineral electron donors. Notable genomic features include (i) genes encoding c-type cytochromes totaling 1 to 2 percent of the genome, which is a proportion greater than for almost all bacterial and archaeal species sequenced to date, (ii) genes encoding two [NiFe]hydrogenases, which is particularly significant because no information on hydrogenases has previously been reported for T. denitrificans and hydrogen oxidation appears to be critical for anaerobic U(IV) oxidation by this species, (iii) a diverse complement of more than 50 genes associated with sulfur-compound oxidation (including sox genes, dsr genes, and genes associated with the AMP-dependent oxidation of sulfite to sulfate), some of which occur in multiple (up to eight) copies, (iv) a relatively large number of genes associated with inorganic ion transport and heavy metal resistance, and (v) a paucity of genes encoding organic-compound transporters, commensurate with obligate chemolithoautotrophy. Ultimately, the genome sequence of T. denitrificans will enable elucidation of the mechanisms of aerobic and anaerobic sulfur-compound oxidation by {beta}-proteobacteria and will help reveal the molecular basis of this organism's role in major biogeochemical cycles (i.e., those involving sulfur, nitrogen, and carbon) and groundwater restoration.

  19. Properties of sugarcane waste-derived bio-oils obtained by fixed-bed fire-tube heating pyrolysis.

    PubMed

    Islam, Mohammad Rofiqul; Parveen, Momtaz; Haniu, Hiroyuki

    2010-06-01

    Agricultural waste in the form of sugarcane bagasse was pyrolyzed in a fixed-bed fire-tube heating reactor under different pyrolysis conditions to determine the role of final temperature, sweeping gas flow rate and feed size on the product yields. Final temperature range studied was between 375 and 575 degrees C and the highest liquid product yield was obtained at 475 degrees C. Liquid products obtained under the most suitable conditions were characterized by physical properties, elemental analysis, GCV, FT-IR, (1)H NMR analysis and distillation. The empirical formula of the bio-oil with heating value of 23.5MJ/kg was established as CH(1.68)O(0.557)N(0.012). Comparison with other approaches showed that the liquid product yield by this simpler reactor system was higher with better physico-chemical properties as fuel. These findings show that fixed-bed fire-tube heating pyrolysis is a good option for production of bio-oils from biomass solid wastes.

  20. The production of pure pressurised hydrogen by the reformer-steam iron process in a fixed bed reactor system

    NASA Astrophysics Data System (ADS)

    Nestl, Stephan; Voitic, Gernot; Lammer, Michael; Marius, Bernhard; Wagner, Julian; Hacker, Viktor

    2015-04-01

    In this paper a fixed bed chemical looping process for the decentralised production of pure pressurised hydrogen for fuel cell applications is described. CH4 is converted to a syngas using conventional steam reforming. The syngas is directly used for the reduction of an iron based oxygen carrier. A consecutive oxidation step using steam leads to the formation of pure pressurised hydrogen. A thermodynamic analysis was performed in order to investigate feasible conditions for the syngas generation and reduction step. Experiments using pure hydrogen as well as an artificial syngas mixture showed the feasibility of the process for the production of pressurised hydrogen. A stable hydrogen production at a pressure of 8-11 bar(g) was achieved and only minor impurities of 700 ppm of carbon dioxide but no signs of carbon monoxide were detected in the produced hydrogen. Although the active surface decreased from 7.5 m2 g-1 to 0.9 m2 g-1 only moderate losses of reactivity were measured in the fixed bed reactor. Thermogravimetric analysis showed a loss of 9% of reactive material over nine cycles, presumably due to sintering effects.

  1. Fixed-bed biosorption of cadmium using immobilized Scenedesmus obliquus CNW-N cells on loofa (Luffa cylindrica) sponge.

    PubMed

    Chen, Bor-Yann; Chen, Chun-Yen; Guo, Wan-Qian; Chang, Hao-Wei; Chen, Wen-Ming; Lee, Duu-Jong; Huang, Chieh-Chen; Ren, Nan-Qi; Chang, Jo-Shu

    2014-05-01

    A continuous fixed-bed biosorption process was established for cadmium (Cd) removal by Scenedesmus obliquus CNW-N (isolated from southern Taiwan) cells immobilized onto loofa sponge. This immobilized-cell biosorption process allows better recovery and reusability of the microalgal biomass. The growth of microalgae on the matrix support with appropriate nutrient supplementation could enhance the overall metal removal activity. Major operating parameters (e.g., feeding flow rate, cycle number of medium replacement, and particle diameter of the sponge) were studied for treatability evaluation. The most promising cell growth on the sponge support was obtained at a flow rate of 0.284 bed volume (BV)/min, sponge particle diameter of 1 cm, and with one cycle of medium replacement. The performance of fixed-bed biosorption (adsorption capacity of 38.4 mg, breakthrough time at 15.5 h) was achieved at a flow rate of 5 ml/min with an influent concentration of 7.5 mg Cd/l. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Batch and continuous (fixed-bed column) biosorption of crystal violet by Artocarpus heterophyllus (jackfruit) leaf powder.

    PubMed

    Saha, Papita Das; Chakraborty, Sagnik; Chowdhury, Shamik

    2012-04-01

    In this study, batch and fixed-bed column experiments were performed to investigate the biosorption potential of Artocarpus heterophyllus (jackfruit) leaf powder (JLP) to remove crystal violet (CV) from aqueous solutions. Batch biosorption studies were carried out as a function of solution pH, contact time, initial dye concentration and temperature. The biosorption equilibrium data showed excellent fit to the Langmuir isotherm model with maximum monolayer biosorption capacity of 43.39 mg g(-1) at pH 7.0, initial dye concentration=50 mg L(-1), temperature=293 K and contact time=120 min. According to Dubinin-Radushkevich (D-R) isotherm model, biosorption of CV by JLP was chemisorption. The biosorption kinetics followed the pseudo-second-order kinetic model. Thermodynamic analysis revealed that biosorption of CV from aqueous solution by JLP was a spontaneous and exothermic process. In order to ascertain the practical applicability of the biosorbent, fixed-bed column studies were also performed. The breakthrough time increased with increasing bed height and decreased with increasing flow rate. The Thomas model as well as the BDST model showed good agreement with the experimental results at all the process parameters studied. It can be concluded that JLP is a promising biosorbent for removal of CV from aqueous solutions. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Backwash intensity and frequency impact the microbial community structure and function in a fixed-bed biofilm reactor.

    PubMed

    Li, Xu; Yuen, Wangki; Morgenroth, Eberhard; Raskin, Lutgarde

    2012-11-01

    Linkages among bioreactor operation and performance and microbial community structure were investigated for a fixed-bed biofilm system designed to remove perchlorate from drinking water. Perchlorate removal was monitored to evaluate reactor performance during and after the frequency and intensity of the backwash procedure were changed, while the microbial community structure was studied using clone libraries and quantitative PCR targeting the 16S rRNA gene. When backwash frequency was increased from once per month to once per day, perchlorate removal initially deteriorated and then recovered, and the relative abundance of perchlorate-reducing bacteria (PRB) initially increased and then decreased. This apparent discrepancy suggested that bacterial populations other than PRB played an indirect role in perchlorate removal, likely by consuming dissolved oxygen, a competing electron acceptor. When backwash intensity was increased, the reactor gradually lost its ability to remove perchlorate, and concurrently the relative abundance of PRB decreased. The results indicated that changes in reactor operation had a profound impact on reactor performance through altering the microbial community structure. Backwashing is an important yet poorly characterized procedure when operating fixed-bed biofilm reactors. Compared to backwash intensity, changes in backwash frequency exerted less disturbance on the microbial community in the current study. If this finding can be confirmed in future work, backwash frequency may serve as the primary parameter when optimizing backwash procedures.

  4. A fixed-bed column for phosphate removal from aqueous solutions using an andosol-bagasse mixture.

    PubMed

    Woumfo, Emmanuel Djoufac; Siéwé, Jean Mermoz; Njopwouo, Daniel

    2015-03-15

    It is difficult to eliminate phosphate from large volumes of water in batch mode using an adsorbent such as andosol. In a fixed-bed column, andosol has a very low permeability. In this study, andosol was mixed with bagasse to increase permeability. The mixture was then applied for the adsorption of phosphate in a fixed-bed column. Optimum and stable permeability was obtained with a 50/50 mixture of andosol and bagasse. The maximum adsorption capacity obtained was 4.18 mg/g for a column with a bed depth of 1.8 cm and a flow rate of 4 mL/min. The experimental data fit best to Thomas and Adam-Bohart models. These experimental results were applied in the treatment of natural phosphate-containing water from Yaoundé Municipal Lake in Cameroon. Column performance increased by 60% due to the presence of Ca(2+) and Mg(2+) in the natural water. These cations form complexes with phosphate at the andosol surface. The standard enthalpy 15.964 kj/mol indicated that phosphate adsorption on andosol-bagasse mixture was an endothermic process. Kinetic experiments demonstrated that phosphate adsorption fitted better with a pseudo-second-order model. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Modeling competitive adsorption of mixtures of volatile organic compounds in a fixed-bed of beaded activated carbon.

    PubMed

    Tefera, Dereje Tamiru; Hashisho, Zaher; Philips, John H; Anderson, James E; Nichols, Mark

    2014-05-06

    A two-dimensional mathematical model was developed to study competitive adsorption of n-component mixtures in a fixed-bed adsorber. The model consists of an isotherm equation to predict adsorption equilibria of n-component volatile organic compounds (VOCs) mixture from single component isotherm data, and a dynamic adsorption model, the macroscopic mass, energy and momentum conservation equations, to simulate the competitive adsorption of the n-components onto a fixed-bed of adsorbent. The model was validated with experimentally measured data of competitive adsorption of binary and eight-component VOCs mixtures onto beaded activated carbon (BAC). The mean relative absolute error (MRAE) was used to compare the modeled and measured breakthrough profiles as well as the amounts of adsorbates adsorbed. For the binary and eight-component mixtures, the MRAE of the breakthrough profiles was 13 and 12%, respectively, whereas, the MRAE of the adsorbed amounts was 1 and 2%, respectively. These data show that the model provides accurate prediction of competitive adsorption of multicomponent VOCs mixtures and the competitive adsorption isotherm equation is able to accurately predict equilibrium adsorption of VOCs mixtures.

  6. Heterogeneous Fenton degradation of organic dyes in batch and fixed bed using La-Fe montmorillonite as catalyst.

    PubMed

    Fida, Hussain; Zhang, Gaoke; Guo, Sheng; Naeem, Abdul

    2017-03-15

    The La-Fe montmorillonite (La-Fe MMT) composite was synthesized by a simple precipitation method and was used for the degradation of dyes in both batch and fixed bed experiments. X-ray diffraction (XRD) and high-resolution transmission electron microscope analysis (HRTEM) confirmed the existence of Fe2O3 and La2O3 in the composite. The presence of La enhanced the degradation efficiency of dyes by the composite at neutral pH and results in little iron leaching consequently increasing the lifetime. More than 97% and 96% removal of the MB and RhB (100mg/L each) by the La-Fe MMT Fenton system could be achieved in less than 1h. The catalyst also exhibited excellent efficiency in fixed bed reactor with 91% MB degradation corresponds to 65% COD removal, even after 200h of use. The factors such as solution pH, catalyst dosage, H2O2 dosage and temperature on the degradation of dyes were investigated. Fluorescence and quenchers experiments indicated that OH was the main reactive species for the degradation of dyes. Due to the low cost, efficient reactivity, high stability and low metal leaching, the La-Fe MMT possesses a great potential to be a green catalyst for the heterogeneous Fenton-like degradation of hazardous dyes. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Feasibility of treating swine manure in an anaerobic sequencing batch biofilm reactor with mechanical stirring.

    PubMed

    de Pinho, Samantha Cristina; Fernandes, Bruna Soares; Rodrigues, José Alberto D; Ratusznei, Suzana Maria; Foresti, Eugenio; Zaiat, Marcelo

    2005-02-01

    Anaerobic sequencing batch reactors containing granular or flocculent biomass have been employed successfully in the treatment of piggery wastewater. However, the studies in which these reactors were employed did not focus specifically on accelerating the hydrolysis step, even though the degradation of this chemical oxygen demand (COD) fraction is likely to be the limiting step in many investigations of this type of wastewater. The mechanically stirred anaerobic sequencing batch biofilm reactor offers an alternative for hastening the hydrolysis step, because mechanical agitation can help to speed up the reduction of particle sizes in the fraction of particulate organic matter. In the present study, a 4.5-L reactor was operated at 30 degrees C, with biomass immobilized on cubic polyurethane foam matrices (1 cm of side) and mechanical stirring provided by three flat-blade turbines (6 cm) at agitation rates varying from 0 to 500 rpm. The reactor was operated to treat diluted swine waste, and mechanical stirring efficiently improved degradation of the suspended COD. The operational data indicate that the reactor remained stable during the testing period. After 2 h of operation at 500 rpm, the suspended COD decreased by about 65% (from 1500 to 380 mg/L). Apparent kinetic constants were also calculated by modified first-order expressions.

  8. TiO2-photocatalyzed As(III) oxidation in a fixed-bed, flow-through reactor.

    PubMed

    Ferguson, Megan A; Hering, Janet G

    2006-07-01

    Compliance with the U.S. drinking water standard for arsenic (As) of 10 microg L(-1) is required in January 2006. This will necessitate implementation of treatment technologies for As removal by thousands of water suppliers. Although a variety of such technologies is available, most require preoxidation of As(III) to As(V) for efficient performance. Previous batch studies with illuminated TiO2 slurries have demonstrated that TiO2-photocatalyzed AS(III) oxidation occurs rapidly. This study examined reaction efficiency in a flow-through, fixed-bed reactor that provides a better model for treatment in practice. Glass beads were coated with mixed P25/sol gel TiO2 and employed in an upflow reactor irradiated from above. The reactor residence time, influent As(III) concentration, number of TiO2 coatings on the beads, solution matrix, and light source were varied to characterize this reaction and determine its feasibility for water treatment. Repeated usage of the same beads in multiple experiments or extended use was found to affect effluent As(V) concentrations but not the steady-state effluent As(III) concentration, which suggests that As(III) oxidation at the TiO2 surface undergoes dynamic sorption equilibration. Catalyst poisoning was not observed either from As(V) or from competitively adsorbing anions, although the higher steady-state effluent As(III) concentrations in synthetic groundwater compared to 5 mM NaNO3 indicated that competitive sorbates in the matrix partially hinder the reaction. A reactive transport model with rate constants proportional to incident light at each bead layer fit the experimental data well despite simplifying assumptions. TiO2-photocatalyzed oxidation of As(III) was also effective under natural sunlight. Limitations to the efficiency of As(III) oxidation in the fixed-bed reactor were attributable to constraints of the reactor geometry, which could be overcome by improved design. The fixed-bed TiO2 reactor offers an environmentally

  9. Microbial sequencing methods for monitoring of anaerobic treatment of antibiotics to optimize performance and prevent system failure.

    PubMed

    Aydin, Sevcan

    2016-06-01

    As a result of developments in molecular technologies and the use of sequencing technologies, the analyses of the anaerobic microbial community in biological treatment process has become increasingly prevalent. This review examines the ways in which microbial sequencing methods can be applied to achieve an extensive understanding of the phylogenetic and functional characteristics of microbial assemblages in anaerobic reactor if the substrate is contaminated by antibiotics which is one of the most important toxic compounds. It will discuss some of the advantages and disadvantages associated with microbial sequencing techniques that are more commonly employed and will assess how a combination of the existing methods may be applied to develop a more comprehensive understanding of microbial communities and improve the validity and depth of the results for the enhancement of the stability of anaerobic reactors.

  10. Development of a fixed-bed anammox reactor with high treatment potential.

    PubMed

    Okamoto, Hiroyuki; Kawamura, Kimito; Nishiyama, Takashi; Fujii, Takao; Furukawa, Kenji

    2013-02-01

    A plug-flow type anaerobic ammonium oxidation (anammox) reactor was developed using malt ceramics (MC) produced from carbonized spent grains as the biomass carriers for anammox sludge. Partial nitrified effluent of the filtrate from the sludge dehydrator of a brewery company was used as influent to a 20 L anammox reactor using MC. An average volumetric nitrogen removal rate (VNR) of 8.78 kg-N/m(3)/day was maintained stably for 76 days with 1 h of HRT. In a larger anammox reactor (400 L), an average VNR of 4.84 kg-N/m(3)/day could be maintained for 86 days during the treatment of low strength synthetic inorganic wastewater. As a result of bacterial community analysis for the 20 L anammox reactor, Asahi BRW1, probably originating from the wastewater collected at Asahi Breweries, was detected as the dominant anammox bacterium. These anammox reactors were characterized by a high NH(4)-N removal capacity for low strength wastewater with a short hydraulic retention time.

  11. Environmental implications of small fixed-bed gasifiers for industry. [Assumes 500 small gasifiers in 1990 and 2500 in 2000

    SciTech Connect

    Dobson, J.E.; Cushman, R.M.; Walsh, P.J.

    1981-05-01

    The Oak Ridge National Laboratory is responsible for an assessment of the environmental implications of small fixed-bed coal gasifiers for industry. The assessment focuses on the industrial utilization of low energy gas (often called low-Btu gas) in the range of 3708 to 7416 kJ/m/sup 3/ manufactured on-site or nearby in a coal-air-steam reaction process. The major risk is in occupational health due to potential exposure to toxic substances. This risk to workers is considerably greater than the risk to the public at large. The major sources of occupational exposure will be process steam leaks, accidental spills, and maintenance operations. The composition of the process stream produced during low-Btu gasification is not well know at present.

  12. Fixed-bed column studies on a modified chitosan hydrogel for detoxification of aqueous solutions from copper (II).

    PubMed

    Kavianinia, Iman; Plieger, Paul G; Kandile, Nadia G; Harding, David R K

    2012-10-01

    A new efficient, low cost chitosan based biosorbent was successfully prepared and employed for the biosorption of copper ions from an aqueous solution using a fixed bed column. Pyromellitic dianhydride crosslinked chitosan as the new adsorbent was characterized by SEM, FTIR spectroscopy, X-ray diffraction, thermogravimetric analysis and solid state (13)C NMR analysis. Scanning electron microscopy coupled with an X-ray energy dispersed analysis for the copper-equilibrated biomass confirmed the presence of Cu(II) ions on the surface of the hydrogel. Thermogravimetric analysis showed a significant improvement in the thermal stability of the new hydrogel compared to pure chitosan. Kinetic models were applied to predict the breakthrough curves. This study shows that the prepared hydrogel based on modified chitosan could be utilized as an efficient bioadsorbent for the removal of copper ions from wastewater. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. The development of a computer model for a fixed bed gasifier and its use for optimization and control.

    PubMed

    Gøbel, Benny; Henriksen, Ulrik; Jensen, Torben Kvist; Qvale, Bjørn; Houbak, Niels

    2007-07-01

    The development of a mathematical model of a fixed-bed gasifier is described. The model was used for studies of the stationary performance of the gasifier and the results were compared to experimental results. The model was also used in an effort to identify an efficient control strategy for the operation during load changes. The resulting strategy was very simple and has been implemented in an unmanned, automatically controlled, power plant that was operated for over 3000h. The mathematical model was based on conservation of mass and energy in a simple one-dimensional flow, chemical equilibrium in the gas phase, and a Langmuir-Hinshelwood correlation describing the reaction kinetics in the char. The results of the thermo-gravimetric analysis experiments required to determine the reactivity for char of beech as a function of temperature, gas composition and conversion ratio of the char are presented.

  14. Study on co-pyrolysis characteristics of rice straw and Shenfu bituminous coal blends in a fixed bed reactor.

    PubMed

    Li, Shuaidan; Chen, Xueli; Liu, Aibin; Wang, Li; Yu, Guangsuo

    2014-03-01

    Co-pyrolysis behaviors of rice straw and Shenfu bituminous coal were studied in a fixed bed reactor under nitrogen atmosphere. The pyrolysis temperatures were 700°C, 800°C and 900°C, respectively. Six different biomass ratios were used. Gas, tar components were analyzed by a gas chromatograph and a gas chromatography-mass spectrometry respectively. Under co-pyrolysis conditions, the gas volume yields are higher than the calculated values. Co-pyrolysis tar contains more phenolics, less oxygenate compounds than calculated values. The addition of biomass changes the atmosphere during the pyrolysis process and promotes tar decomposition. The SEM results show that the differences between the blended char and their parents char are not significant. The results of char yields and ultimate analysis also show that no significant interactions exist between the two kinds of particles. The changes of gas yield and components are caused by the secondary reactions and tar decomposition.

  15. Effect of small-scale biomass gasification at the state of refractory lining the fixed bed reactor

    SciTech Connect

    Janša, Jan Peer, Vaclav Pavloková, Petra

    2016-06-30

    The article deals with the influence of biomass gasification on the condition of the refractory lining of a fixed bed reactor. The refractory lining of the gasifier is one part of the device, which significantly affects the operational reliability and durability. After removing the refractory lining of the gasifier from the experimental reactor, there was done an assessment how gasification of different kinds of biomass reflected on its condition in terms of the main factors affecting its life. Gasification of biomass is reflected on the lining, especially through sticking at the bottom of the reactor. Measures for prolonging the life of lining consist in the reduction of temperature in the reactor, in this case, in order to avoid ash fusion biomass which it is difficult for this type of gasifier.

  16. Fixed-bed gasification research using US coals. Volume 3. Gasification of Rosebud sub-bituminous coal

    SciTech Connect

    Thimsen, D.; Maurer, R.E.; Pooler, A.R.; Pui, D.; Liu, B.; Kittelson, D.

    1985-03-31

    A single-staged, fixed-bed Wellman-Galusha gasifier coupled with a hot, raw gas combustion system and scrubber has been used to gasify numerous coals from throughout the United States. The gasification test program is organized as a cooperative effort by private industrial participants and governmental agencies. The consortium of participants is organized under the Mining and Industrial Fuel Gas (MIFGa) Group. This report is the third volume in a series of documents prepared by Black, Sivalls and Bryson, Incorporated and describes the gasification of Rosebud subbituminous coal during the time period November 2-20, 1982. Test results and data are presented for the gasification of the coal and the operation of a slipstream tar scrubber to cool the gas and remove condensed tar. 5 refs., 29 figs., 18 tabs.

  17. Experimental study on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed.

    PubMed

    Liang, Ligang; Sun, Rui; Fei, Jun; Wu, Shaohua; Liu, Xiang; Dai, Kui; Yao, Na

    2008-10-01

    A fixed-bed experimental reactor was employed to reveal the combustion characteristics in simulated municipal solid waste (MSW) beds. Temperature distributions, ignition front velocity, bed weight were measured during combustion and gas analysis was also performed for O2, CO2, CO, CxHy, NO, HCN. The moisture content in MSW was varied. For higher moisture content, the drying of material was finished much later and the ignition front temperatures, ignition front velocity and overall burning rate were found to drop. The average concentration of CO and CO2 from the bed was inversely proportional to the moisture level, and the highest concentrations of CO and CxHy were observed at middle level of investigated fuel moisture content. Measurements showed that NO and HCN emitted from the bed and reached the peaks simultaneously with the volatile matters, and the conversion ratio of fuel nitrogen to NO and average concentration of NO decreased with increasing moisture content.

  18. Cr(III) removal from aqueous solutions: a straightforward model approaching of the adsorption in a fixed-bed column.

    PubMed

    Dorado, Antonio David; Gamisans, Xavier; Valderrama, Cesar; Solé, Montse; Lao, Conxita

    2014-01-01

    Prediction of breakthrough curves for continuous sorption characterization is generally performed by means of simple and simplified equations. These expressions hardly have any physical meaning and, also do not allow extrapolation. A novel and simple approach, based on unsteady state mass balances, is presented herein for the simulation of the adsorption of Cr(III) ions from aqueous onto a low-cost adsorbent (leonardite). The proposed model overcomes the limitations of the commonly used analytical solution-based models without the need for complex mathematical methods. A set of experimental breakthrough curves obtained from lab-scale, fixed-bed columns was used to calibrate and validate the proposed model with a minimum number of parameters to be adjusted.

  19. Alkylation of Benzene with Propylene in a Flow-Through Membrane Reactor and Fixed-Bed Reactor: Preliminary Results

    PubMed Central

    Torres-Rodríguez, Miguel; Gutiérrez-Arzaluz, Mirella; Mugica-Álvarez, Violeta; Aguilar-Pliego, Julia; Pergher, Sibele

    2012-01-01

    Benzene alkylation with propylene was studied in the gas phase using a catalytic membrane reactor and a fixed-bed reactor in the temperature range of 200–300 °C and with a weight hourly space velocity (WHSV) of 51 h−1. β-zeolite was prepared by hydrothermal synthesis using silica, aluminum metal and TEAOH as precursors. The membrane’s XRD patterns showed good crystallinity for the β-zeolite film, while scanning electron microscopy SEM results indicated that its random polycrystalline film was approximately 1 μm thick. The powders’ specific area was determined to be 400 m2·g−1 by N2 adsorption/desorption, and the TPD results indicated an overall acidity of 3.4 mmol NH3·g−1. Relative to the powdered catalyst, the catalytic membrane showed good activity and product selectivity for cumene. PMID:28817013

  20. Continuous flow adsorption of methylene blue by cellulose nanocrystal-alginate hydrogel beads in fixed bed columns.

    PubMed

    Mohammed, Nishil; Grishkewich, Nathan; Waeijen, Herman Ambrose; Berry, Richard M; Tam, Kam Chiu

    2016-01-20

    The adsorption behavior of methylene blue by cellulose nanocrystal-alginate (CNC-ALG) hydrogel beads in a fixed bed column was studied by varying the initial dye concentrations, bed depths and flow rates. An unusual phenomenon was observed in the early phase of the adsorption, and the phenomenon was elucidated by varying other critical design parameters, such as the flow direction, diameter of column and composition of adsorbent. The swelling and shrinkage of hydrogel beads during the adsorption was responsible for the anomalous concentration versus time profile of the adsorption process. The maximum adsorption capacity of the column was 255.5mg/g, which is in agreement with the batch study determined from the Langmuir adsorption isotherm. A comprehensive understanding on the adsorption mechanism of CNC-ALG hydrogel beads during the early stages of adsorption was derived from this study.

  1. Fixed bed column study for Cu (II) removal from aqueous solution using water hyacinth (Eichornia crassipes) biomass.

    PubMed

    Gandhimathi, R; Ramesh, S T; Yadu, Anubhav; Bharathi, K S

    2013-07-01

    This paper reports the results of the study on the performance of low-cost biosorbent water hyacinth (WH) in removing Cu (II) from aqueous solution. The adsorbent material adopted was found to be an efficient media for the removal of Cu (II) in continuous mode using fixed bed column. The column studies were conducted with 10 mg/L metal solution with a flow rate of 10 mL/min with different bed depths such as 10, 20 and 30 cm. The column design parameters like adsorption rate constant, adsorption capacity and minimum bed depth were calculated. It was found that, the adsorption capacity of copper ions by water hyacinth increased by increasing the bed depth and the contact time.

  2. Development and Optimization of AAV hFIX Particles by Transient Transfection in an iCELLis(®) Fixed-Bed Bioreactor.

    PubMed

    Powers, Alicia D; Piras, Bryan A; Clark, Robert K; Lockey, Timothy D; Meagher, Michael M

    2016-06-01

    Adeno-associated virus (AAV) vectors are increasingly popular in gene therapy because they are unassociated with human disease, replication dependent, and less immunogenic than other viral vectors and can infect a variety of cell types. These vectors have been used in over 130 clinical trials, and one AAV product has been approved for treatment of lipoprotein lipase deficiency in Europe. To meet the demand for the increasing quantities of AAV required for clinical trials and treatment, a scalable high-capacity technology is required. Bioreactors meet these requirements but limited options are available for adherent HEK 293T/17 cells. Here we optimize the transient transfection of HEK293T/17 cells for the production of AAV human factor IX in a disposable fixed-bed bioreactor, the iCELLis(®) Nano (PALL Corporation). A fixed bed in the center of the iCELLis bioreactor is surrounded by culture medium that is pumped through the bed from the bottom of the bioreactor so that a thin film of the medium overflows the bed and is replenished with oxygen and depleted of CO2 as it returns to the surrounding medium reservoir. We show that this fixed-bed bioreactor can support as many as 2.5 × 10(8) cells/ml of fixed bed (1.9 × 10(6) cells/cm(2)). By optimizing culture and transfection parameters such as the concentration of DNA for transfection, day of harvest, size of PEI/DNA particles, and transfection medium, and adding an additional medium change to the process, we increased our yield to as high as 9.0 × 10(14) viral particles per square meter of fixed bed. We also show an average GFP transfection of 97% of cells throughout the fixed bed. These yields make the iCELLis a promising scalable technology for the clinical production of AAV gene therapy products.

  3. Effects of the antimicrobial tylosin on the microbial community structure of an anaerobic sequencing batch reactor.

    PubMed

    Shimada, Toshio; Li, Xu; Zilles, Julie L; Morgenroth, Eberhard; Raskin, Lutgarde

    2011-02-01

    The effects of the antimicrobial tylosin on a methanogenic microbial community were studied in a glucose-fed laboratory-scale anaerobic sequencing batch reactor (ASBR) exposed to stepwise increases of tylosin (0, 1.67, and 167 mg/L). The microbial community structure was determined using quantitative fluorescence in situ hybridization (FISH) and phylogenetic analyses of bacterial 16S ribosomal RNA (rRNA) gene clone libraries of biomass samples. During the periods without tylosin addition and with an influent tylosin concentration of 1.67 mg/L, 16S rRNA gene sequences related to Syntrophobacter were detected and the relative abundance of Methanosaeta species was high. During the highest tylosin dose of 167 mg/L, 16S rRNA gene sequences related to Syntrophobacter species were not detected and the relative abundance of Methanosaeta decreased considerably. Throughout the experimental period, Propionibacteriaceae and high GC Gram-positive bacteria were present, based on 16S rRNA gene sequences and FISH analyses, respectively. The accumulation of propionate and subsequent reactor failure after long-term exposure to tylosin are attributed to the direct inhibition of propionate-oxidizing syntrophic bacteria closely related to Syntrophobacter and the indirect inhibition of Methanosaeta by high propionate concentrations and low pH. © 2010 Wiley Periodicals, Inc.

  4. Influence of biofilm density on anaerobic sequencing batch biofilm reactor treating mustard tuber wastewater.

    PubMed

    Chai, Hongxiang; Kang, Wei

    2012-11-01

    Considering the characteristics of high salinity, high concentration of organic matter, and high biodegradability, a new and efficient anaerobic sequencing batch biofilm reactor (ASBBR) was chosen as an anaerobic pretreatment unit to treat most organic compounds in mustard tuber wastewater. By changing the biofilm density of the reactor, the test was carried out to find out the influence of biofilm density on effluent COD, the content of the sludge dehydrogenase, and gas production rate. Results showed that under the condition of 30 °C, draining ratio of 1/3, and 2 days of hydraulic retention time, COD removal rate increased from 71.5 to 90.5 % when the biofilm density increased from 15 to 50 %; however, COD removal rate increased from 90.5 to 91.3 % when the biofilm density increased from 50 to 70 %. According to the influence of biofilm density on effluent COD, the content of the sludge dehydrogenase, and gas production rate, ASBBR should take 50 % biofilm density in mustard wastewater treatment. At the same time, these design parameters can be used to guide practical engineering.

  5. Combined effect of erythromycin, tetracycline and sulfamethoxazole on performance of anaerobic sequencing batch reactors.

    PubMed

    Aydin, Sevcan; Ince, Bahar; Cetecioglu, Zeynep; Arikan, Osman; Ozbayram, E Gozde; Shahi, Aiyoub; Ince, Orhan

    2015-06-01

    The combined effects of erythromycin-tetracycline-sulfamethoxazole (ETS) and sulfamethoxazole-tetracycline (ST) antibiotics on the performance of anaerobic sequencing batch reactors were studied. A control reactor was fed with wastewater that was free of antibiotics, while two additional reactors were fed with ETS and ST. The way in which the ETS and ST mixtures impact COD removal, VFA production, antibiotic degradation, biogas production and composition were investigated. The effects of the ETS mixtures were different from the ST mixtures, erythromycin can have an antagonistic effect on sulfamethoxazole and tetracycline. The anaerobic pre-treatment of these antibiotics can represent a suitable alternative to the use of chemical treatments for concentrations at 10 mg/L of S and 1 mg/L of T; 2 mg/L of E, 2 mg/L of T and 20 mg/L of S for the ST and ETS reactors respectively, which corresponds to min 70% COD removal efficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Insect cell entrapment, growth and recovering using a single-use fixed-bed bioreactor. Scaling up and recombinant protein production.

    PubMed

    Ventini-Monteiro, D; Dubois, S; Astray, R M; Castillo, J; Pereira, C A

    2015-12-20

    Insect cells are largely used for industrial production of vaccines, viral vectors and recombinant proteins as well as in research and development as an important tool for biology and bioprocess studies. They grow in suspension and are semi-adherent cells. Among the cell culture systems enabling scalable bioprocess the single-use fixed-bed iCELLis(®) bioreactors offer great advantages. We have established the conditions for Drosophila melanogaster Schneider 2 (S2) and Spodoptera frugiperda (Sf9) cells entrapment into the fixed-bed, cell growth and recover from the fixed-bed once high cell densities were attained. Our established protocol allowed these cells, at a cell seeding of 2×1E5 cells/microfiber carriers (MC) (3.5×1E6cells/mL; 1.7×1E4cells/cm(2)), to grow inside a 4m(2)/200mL fixed-bed attaining a concentration of 5.3×1E6 cells/MC (9.5×1E7cells/mL; 4.7×1E5 cells/cm(2)) for S2 cells or 4.6×1E6 cells/MC (8×1E7cells/mL; 4.1×1E5cells/cm(2)) for Sf9 cells. By washing the fixed-bed, entrapped cells could then be recovered from the fixed-bed at a high rate (>85%) with high viability (>95%) by increasing the agitation to 1200/1500rpm. Although the cell yields in the fixed-bed bioreactor were comparable to those obtained in a stirred tank (respectively, 1.3×1E10 and 2.5×1E10 total cells), S2 cells stably transfected with a cDNA coding for the rabies virus glycoprotein (RVGP) showed a 30% higher preserved rRVGP production (2.5±0.1 and 1.9±0.1μg/1E7 cells), as evidenced by a conformational ELISA evaluation. These findings demonstrate not only the possibility to entrap, cultivate to high densities and recover insect cells using a single-use fixed-bed bioreactor, but also that this system provides suitable physiological conditions for the entrapped cells to produce a cell membrane associated recombinant protein with higher specific biological activity as compared to classical suspension cell cultures.

  7. Kinetics of psychrophilic anaerobic sequencing batch reactor treating flushed dairy manure.

    PubMed

    Ma, Jingwei; Yu, Liang; Frear, Craig; Zhao, Quanbao; Li, Xiujin; Chen, Shulin

    2013-03-01

    In this study, a new strategy, improving biomass retention with fiber material present within the dairy manure as biofilm carriers, was evaluated for treating flushed dairy manure in a psychrophilic anaerobic sequencing batch reactor (ASBR). A kinetic study was carried out for process control and design by comparing four microbial growth kinetic models, i.e. first order, Grau, Monod and Chen and Hashimoto models. A volumetric methane production rate of 0.24L/L/d of and a specific methane productivity of 0.19L/gVSloaded were achieved at 6days HRT. It was proved that an ASBR using manure fiber as support media not only improved methane production but also reduced the necessary HRT and temperature to achieve a similar treating efficiency compared with current technologies. The kinetic model can be used for design and optimization of the process. Copyright © 2012. Published by Elsevier Ltd.

  8. Sequence of Events During Germination of Putrefactive Anaerobe 3679 Spores1

    PubMed Central

    Uehara, Minoru; Frank, Hilmer A.

    1967-01-01

    The sequence of changes during germination of putrefactive anaerobe 3679h spores was studied under aerobic conditions in a solution containing l-alanine and sodium pyrophosphate. Evidence that specific changes occurred in two distinct regions of the spore is given by data on several criteria that were used to measure germination. During the initial stage of germination, the absorbancy decreased, dipicolinic acid was released, the spores lost their resistance to heat and toxic chemicals, and the spore periphery (cortex) darkened gradually under phase-contrast microscopy. The final stage of germination was characterized by changes in the central spore region (core), notably phase darkening of the spore center and stainability with mercurochrome, and by a slight additional absorbancy decrease. Images PMID:4166552

  9. Draft Genome Sequence of the Anaerobic Ammonium-Oxidizing Bacterium “Candidatus Brocadia sp. 40”

    PubMed Central

    Ali, Muhammad; Haroon, Mohamed Fauzi; Narita, Yuko; Zhang, Lei; Rangel Shaw, Dario; Okabe, Satoshi

    2016-01-01

    The anaerobic ammonium-oxidizing (anammox) bacterium “Candidatus Brocadia sp. 40” demonstrated the fastest growth rate compared to others in this taxon. Here, we report the 2.93-Mb draft genome sequence of this bacterium, which has 2,565 gene-coding regions, 41 tRNAs, and a single rrn operon. PMID:27932661

  10. First Insights into the Genome Sequence of the Strictly Anaerobic Homoacetogenic Sporomusa sphaeroides Strain E (DSM 2875)

    PubMed Central

    Villamizar, Genis Andrés Castillo; Daniel, Rolf

    2017-01-01

    ABSTRACT Here, we report the draft genome sequence of Sporomusa sphaeroides strain E (DSM 2875), a strict anaerobic homoacetogenic bacterium. It is able to grow autotrophically on different one-carbon compounds. The strain possesses several genes of the Wood-Ljungdahl pathway. The genome consists of a single chromosome (4.98 Mb). PMID:28336590

  11. Draft Genome Sequence of an Anaerobic and Extremophilic Bacterium, Caldanaerobacter yonseiensis, Isolated from a Geothermal Hot Stream

    PubMed Central

    Lee, Sang-Jae; Lee, Yong-Jik; Park, Gun-Seok; Kim, Byoung-Chan; Lee, Sang Jun; Shin, Jae-Ho

    2013-01-01

    Caldanaerobacter yonseiensis is a strictly anaerobic, thermophilic, spore-forming bacterium, which was isolated from a geothermal hot stream in Indonesia. This bacterium utilizes xylose and produces a variety of proteases. Here, we report the draft genome sequence of C. yonseiensis, which reveals insights into the pentose phosphate pathway and protein degradation metabolism in thermophilic microorganisms. PMID:24201201

  12. Performance of anaerobic sequencing batch reactor in the treatment of pharmaceutical wastewater containing erythromycin and sulfamethoxazole mixture.

    PubMed

    Aydin, S; Ince, B; Cetecioglu, Z; Ozbayram, E G; Shahi, A; Okay, O; Arikan, O; Ince, O

    2014-01-01

    This study evaluates the joint effects of erythromycin-sulfamethoxazole (ES) combinations on anaerobic treatment efficiency and the potential for antibiotic degradation during anaerobic sequencing batch reactor operation. The experiments involved two identical anaerobic sequencing batch reactors. One reactor, as control unit, was fed with synthetic wastewater while the other reactor (ES) was fed with a synthetic substrate mixture including ES antibiotic combinations. The influence of ES antibiotic mixtures on chemical oxygen demand (COD) removal, volatile fatty acid production, antibiotic degradation, biogas production, and composition were investigated. The influent antibiotic concentration was gradually increased over 10 stages, until the metabolic collapse of the reactors, which occurred at 360 days for the ES reactor. The results suggest that substrate/COD utilization and biogas/methane generation affect performance of the anaerobic reactors at higher concentration. In addition, an average of 40% erythromycin and 37% sulfamethoxazole reduction was achieved in the ES reactor. These results indicated that these antibiotics were partly biodegradable in the anaerobic reactor system.

  13. Enhanced mercury removal from fix-bed reactor by lamella manganese oxide sorbents

    NASA Astrophysics Data System (ADS)

    Cheng, H. W.; Yu, C. T.

    2015-12-01

    Mercury (Hg) is an extremely hazardous metal and attracted more concern because of its high toxicity and bioaccumulation. Several manganese-oxide-containing sorbents prepared by co-precipitation method could exhibit the mercury removal activities toward Hg0. The mercury removal test at the temperature of 300°C has the highest removal efficiency. Under this temperature, the maximum absorption equivalent of Mg-Al-Mn and Mn-Al were up to 90.9 and 247 μg/g, then gradually decreased at 400°C. The mercury removal efficiency declined in the following sequence: Mn-Al > Mg-Al-Mn > Mg-Al-Mn/ACA = Mn/AC(p)> Mn/AC(g), due to the manganese-oxide content formed on the sorbents.

  14. Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed.

    PubMed

    Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

    2015-05-01

    In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on the combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k-ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. A highly efficient polyampholyte hydrogel sorbent based fixed-bed process for heavy metal removal in actual industrial effluent.

    PubMed

    Zhou, Guiyin; Luo, Jinming; Liu, Chengbin; Chu, Lin; Ma, Jianhong; Tang, Yanhong; Zeng, Zebing; Luo, Shenglian

    2016-02-01

    High sorption capacity, high sorption rate, and fast separation and regeneration for qualified sorbents used in removing heavy metals from wastewater are urgently needed. In this study, a polyampholyte hydrogel was well designed and prepared via a simple radical polymerization procedure. Due to the remarkable mechanical strength, the three-dimensional polyampholyte hydrogel could be fast separated, easily regenerated and highly reused. The sorption capacities were as high as 216.1 mg/g for Pb(II) and 153.8 mg/g for Cd(II) owing to the existence of the large number of active groups. The adsorption could be conducted in a wide pH range of 3-6 and the equilibrium fast reached in 30 min due to its excellent water penetration for highly accessible to metal ions. The fixed-bed column sorption results indicated that the polyampholyte hydrogel was particularly effective in removing Pb(II) and Cd(II) from actual industrial effluent to meet the regulatory requirements. The treatment volumes of actual smelting effluent using one fixed bed column were as high as 684 bed volumes (BV) (7736 mL) for Pb(II) and 200 BV (2262 mL) for Cd(II). Furthermore, the treatment volumes of actual smelting effluent using tandem three columns reached 924 BV (31,351 mL) for Pb(II) and 250 BV (8483 mL) for Cd(II), producing only 4 BV (136 mL) eluent. Compared with the traditional high density slurry (HDS) process with large amount of sludge, the proposed process would be expected to produce only a small amount of sludge. When the treatment volume was controlled below 209.3 BV (7103 mL), all metal ions in the actual industrial effluent could be effectively removed (<0.01 mg/L). This wok develops a highly practical process based on polyampholyte hydrogel sorbents for the removal of heavy metal ions from practical wastewater.

  16. Burden of emerging anaerobes in the MALDI-TOF and 16S rRNA gene sequencing era.

    PubMed

    La Scola, Bernard; Fournier, Pierre-Edouard; Raoult, Didier

    2011-06-01

    The isolation of anaerobes from patients has declined in recent years, whereas their detection by molecular techniques has increased. In the present work, we analyzed the application of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing to routine identification of anaerobes in clinical microbiology laboratory. We identified 544 isolates of 79 species by routine culture from deep samples in our hospital. MALDI-TOF MS allowed identification of 332 isolates (61%). The remaining 212 (39%) were identified by 16S rRNA gene sequencing, allowing identification of 202 at the species level. The most common anaerobes were Propionibacterium spp. (12%), Finegoldia magna (4%), Fusobacterium spp. (6%) and Bacteroides spp. (6%). However, among the 79 identified species, seven were new species or genera, including two Prevotella conceptionensis, a species previously detected by our team by amplification and sequencing, five Anaerococcus sp. and one Prevotella sp. Beyond the identification of these new species, we also identified several uncommon or previously not described associations between species and specific pathologic conditions. MALDI-TOF MS-based identification, which will become more effective with future spectra database improvement, will be likely responsible of a burden of emerging anaerobes in clinical microbiology. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Three multidomain esterases from the cellulolytic rumen anaerobe Ruminococcus flavefaciens 17 that carry divergent dockerin sequences.

    PubMed

    Aurilia, V; Martin, J C; McCrae, S I; Scott, K P; Rincon, M T; Flint, H J

    2000-06-01

    Three enzymes carrying esterase domains have been identified in the rumen cellulolytic anaerobe Ruminococcus flavefaciens 17. The newly characterized CesA gene product (768 amino acids) includes an N-terminal acetylesterase domain and an unidentified C-terminal domain, while the previously characterized XynB enzyme (781 amino acids) includes an internal acetylesterase domain in addition to its N-terminal xylanase catalytic domain. A third gene, xynE, is predicted to encode a multidomain enzyme of 792 amino acids including a family 11 xylanase domain and a C-terminal esterase domain. The esterase domains from CesA and XynB share significant sequence identity (44%) and belong to carbohydrate esterase family 3; both domains are shown here to be capable of deacetylating acetylated xylans, but no evidence was found for ferulic acid esterase activity. The esterase domain of XynE, however, shares 42% amino acid identity with a family 1 phenolic acid esterase domain identified from Clostridum thermocellum XynZ. XynB, XynE and CesA all contain dockerin-like regions in addition to their catalytic domains, suggesting that these enzymes form part of a cellulosome-like multienzyme complex. The dockerin sequences of CesA and XynE differ significantly from those previously described in R. flavefaciens polysaccharidases, including XynB, suggesting that they might represent distinct dockerin specificities.

  18. Complete genome sequence of the anaerobic, protein-degrading hyperthermophilic crenarchaeon Desulfurococcus kamchatkensis.

    PubMed

    Ravin, Nikolai V; Mardanov, Andrey V; Beletsky, Alexey V; Kublanov, Ilya V; Kolganova, Tatiana V; Lebedinsky, Alexander V; Chernyh, Nikolai A; Bonch-Osmolovskaya, Elizaveta A; Skryabin, Konstantin G

    2009-04-01

    Desulfurococcus kamchatkensis is an anaerobic organotrophic hyperthermophilic crenarchaeon isolated from a terrestrial hot spring. Its genome consists of a single circular chromosome of 1,365,223 bp with no extrachromosomal elements. A total of 1,474 protein-encoding genes were annotated, among which 205 are exclusive for D. kamchatkensis. The search for a replication origin site revealed a single region coinciding with a global extreme of the nucleotide composition disparity curve and containing a set of crenarchaeon-type origin recognition boxes. Unlike in most archaea, two genes encoding homologs of the eukaryotic initiator proteins Orc1 and Cdc6 are located distantly from this site. A number of mobile elements are present in the genome, including seven transposons representing IS607 and IS200/IS605 families and multiple copies of miniature inverted repeat transposable elements. Two large clusters of regularly interspaced repeats are present; none of the spacer sequences matches known archaeal extrachromosomal elements, except one spacer matches the sequence of a resident gene of D. kamchatkensis. Many of the predicted metabolic enzymes are associated with the fermentation of peptides and sugars, including more than 30 peptidases with diverse specificities, a number of polysaccharide degradation enzymes, and many transporters. Consistently, the genome encodes both enzymes of the modified Embden-Meyerhof pathway of glucose oxidation and a set of enzymes needed for gluconeogenesis. The genome structure and content reflect the organism's nutritionally diverse, competitive natural environment, which is periodically invaded by viruses and other mobile elements.

  19. Nutrient removal, microbial community and sludge settlement in anaerobic/aerobic sequencing batch reactors without enhanced biological phosphorus removal.

    PubMed

    Wu, Guangxue; Rodgers, Michael

    2010-01-01

    Nutrient removal, microbial community and sludge settlement were examined in two 3-litre laboratory-scale anaerobic/aerobic sequencing batch reactors (SBRs). One SBR was operated at 10 degrees C and the other SBR at 20 degrees C. Different from conventional enhanced biological phosphorus removal, most of the soluble sodium acetate was removed in the aerobic phase and no organic carbon uptake or biological phosphorus release occurred in the anaerobic phase. In this type of anaerobic/aerobic SBR, the phosphorus removal and sludge settlement seemed to be unstable, and the dominant microorganism was Zoogloea sp. Although no excess biological phosphorus removal occurred, extracellular phosphorus precipitation contributed a significant proportion to total phosphorus removed. Sludge volume index decreased with increasing phosphorus contents in the biomass under all conditions. The functions of extracellular polymeric substances in sludge settlement and phosphorus removal depended on the environmental conditions applied.

  20. Aqueous phase adsorption of cephalexin by walnut shell-based activated carbon: A fixed-bed column study

    NASA Astrophysics Data System (ADS)

    Nazari, Ghadir; Abolghasemi, Hossein; Esmaieli, Mohamad; Sadeghi Pouya, Ehsan

    2016-07-01

    The walnut shell was used as a low cost adsorbent to produce activated carbon (AC) for the removal of cephalexin (CFX) from aqueous solution. A fixed-bed column adsorption was carried out using the walnut shell AC. The effect of various parameters like bed height (1.5, 2 and 2.5 cm), flow rate (4.5, 6 and 7.5 mL/min) and initial CFX concentration (50, 100 and 150 mg/L) on the breakthrough characteristics of the adsorption system was investigated at optimum pH 6.5. The highest bed capacity of 211.78 mg/g was obtained using 100 mg/L inlet drug concentration, 2 cm bed height and 4.5 mL/min flow rate. Three kinetic models, namely Adam's-Bohart, Thomas and Yoon-Nelson were applied for analysis of experimental data. The Thomas and Yoon-Nelson models were appropriate for walnut shell AC column design under various conditions. The experimental adsorption capacity values were fitted to the Bangham and intra-particle diffusion models in order to propose adsorption mechanisms. The effect of temperature on the degradation of CFX was also studied.

  1. Simultaneous measurement of x-ray absorption spectra and kinetics : a fixed-bed, plug-flow operando reactor.

    SciTech Connect

    Fingland, B. R.; Ribeiro, F. H.; Miller, J. T.; Purdue Univ.

    2009-08-01

    An inexpensive fixed-bed, plug-flow operando reactor is described in which X-ray absorbance and kinetic data can be measured simultaneously. Pt L3 (11.56 keV) XANES and EXAFS data were obtained on a 1.5% Pt/silica catalyst in borosilicate glass reactors of different diameters, 3-6 mm, and thicknesses, 0.3-1.2 mm, some of which are capable of operation at pressures up to about 40 atm. Additionally, polyimide tubular reactors with low absorbance can be used for lower energy edges of the 3d transition metals, or fluorescence detection for low concentration or highly absorbing supports. With the polyimide reactor, however, the pressure is limited to {approx}3.5 atm and the reaction temperature to about 300 C. To validate the reactor, the rate and activation energies for the water-gas shift reaction on 2% Pd, 13.7% Zn on Al2O3 catalyst were within 15% of those obtained in a standard laboratory reactor, which is within laboratory reproducibility. In addition, the Pd K edge (24.35 keV) XANES and EXAFS data on pre-reduced catalyst were identical to that previously determined on a regular cell. The EXAFS data show that the degree of Pd-Zn alloy formation changes with reaction temperature demonstrating the importance of characterizing the catalyst under reaction conditions.

  2. Coalesced chitosan activated carbon composite for batch and fixed-bed adsorption of cationic and anionic dyes.

    PubMed

    Auta, M; Hameed, B H

    2013-05-01

    A renewable waste tea activated carbon (WTAC) was coalesced with chitosan to form composite adsorbent used for waste water treatment. Adsorptive capacities of crosslinked chitosan beads (CCB) and its composite (WTAC-CCB) for Methylene blue dye (MB) and Acid blue 29 (AB29) were evaluated through batch and fixed-bed studies. Langmuir, Freundlich and Temkin adsorption isotherms were tested for the adsorption process and the experimental data were best fitted by Langmuir model and least by Freundlich model; the suitability of fitness was adjudged by the Chi-square (χ(2)) and Marquadt's percent standard deviation error functions. Judging by the values of χ(2), pseudo-second-order reaction model best described the adsorption process than pseudo-first-order kinetic model for MB/AB29 on both adsorbents. After five cycles of adsorbents desorption test, more than 50% WTAC-CCB adsorption efficiency was retained while CCB had <20% adsorption efficiency. The results of this study revealed that WTAC-CCB composite is a promising adsorbent for treatment of anionic and cationic dyes in effluent wastewaters. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Fixed-bed column studies on biosorption of crystal violet from aqueous solution by Citrullus lanatus rind and Cyperus rotundus

    NASA Astrophysics Data System (ADS)

    Bharathi, Kandaswamy Suyamboo; Ramesh, SriKrishna Perumal Thanga

    2013-12-01

    In this study, fixed-bed column experiments were performed to investigate the biosorption potential of two agricultural wastes, Citrullus lanatus rind and Cyperus rotundus to remove Crystal violet (CV) from aqueous solution. The experiments were conducted to study the effects of important parameters such as bed depth (10-30 cm), flow rate (10-20 mL min-1) and initial dye concentration (10-25 mg L-1). Different models like Bed Depth Service Time (BDST) model, Thomas model and Yoon-Nelson model were applied to the experimental sorption data. In the biosorption of Crystal violet by both the sorbents, the BDST model fitted well with the experimental data in the initial region of the breakthrough curve. Also, Yoon-Nelson model was found to show good agreement with the experimental kinetic results as compared to the Thomas model. The sorbents were found to be very potential, as it showed good sorption capacities of 46.68 and 54.24 mg g-1 for CV biosorption by Citrullus lanatus rind and Cyperus rotundus. Recovery of dye was made by eluting 1 N CH3COOH through the exhausted column in downward direction.

  4. Selective CO 2 Capture from Flue Gas Using Metal–Organic Frameworks-A Fixed Bed Study

    SciTech Connect

    Liu, Jian; Tian, Jian; Thallapally, Praveen K.; McGrail, B. Peter

    2012-05-03

    It is important to capture carbon dioxide from flue gas which is considered to be the main reason to cause global warming. CO2/N2 separation by novel adsorbents is a promising method to reduce CO2 emission but effect of water and CO2/N2 selectivity is critical to apply the adsorbents into practical applications. A very well known, Metal Organic Framework, NiDOBDC (Ni-MOF-74 or CPO-27-Ni) was synthesized through a solvothermal reaction and the sample (500 to 800 microns) was used in a fixed bed CO2/N2 breakthrough study with and without H2O. The Ni/DOBDC pellet has a high CO2 capacity of 3.74 mol/kg at 0.15 bar and a high CO2/N2 selectivity of 38, which is much higher than those of reported MOFs and zeolites under dry condition. Trace amount of water can impact CO2 adsorption capacity as well as CO2/N2 selectivity for the Ni/DOBDC. However, Ni/DOBDC can retain a significant CO2 capacity and CO2/N2 selectivity at 0.15 bar CO2 with 3% RH water. These results indicate a promising future to use the Ni/DOBDC in CO2 capture from flue gas.

  5. Pressurized pyrolysis of dried distillers grains with solubles and canola seed press cake in a fixed-bed reactor.

    PubMed

    Ateş, Funda; Miskolczi, Norbert; Saricaoğlu, Beyza

    2015-02-01

    Pressurized pyrolysis of biomasses was carried in a fixed bed reactor to obtain gases, bio-oils and chars at elevated temperatures. The products were characterized by GC-MS, FTIR, viscometer, SEM, BET and EDXRFS methods. Experiments were performed at 1, 5 and 10 bar pressure and 400, 500 and 600°C temperatures. The experimental results show that in all the experimental condition the yield of bio-oil from DDGS as higher than that of canola. Yield of non-condensable gases and chars increased, while that of liquid products decreased by pressure. Increasing pressure favoured the formation of low molecular weight gas, such as H2. Maximum surface area of chars was obtained at atmospheric pressure and the surface areas decreased rapidly with increasing pressure. GC/MS results shows that the amount of fatty acids in bio-oils was increased by increasing pressure and bio-oils showed non-Newtonian behavior. Based on EDXRFS results, bio-oils and char contained lots of elements. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Investigations on humic acid removal from water using surfactant-modified zeolite as adsorbent in a fixed-bed reactor

    NASA Astrophysics Data System (ADS)

    Elsheikh, Awad F.; Ahmad, Umi Kalthom; Ramli, Zainab

    2016-12-01

    Natural organic matter (NOM) is ubiquitous in aquatic environments and has recently become an issue of worldwide concern in drinking water treatment. The major component of NOM is humic acids (HA). In this study, a natural zeolite (mordenite) was modified employing hexadecyltrimethylammonium bromide (HDTMA) to enhance greater efficient sites for sorption of HA. The natural zeolite and surfactant-modified zeolite (SMZ) were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectrometer (FT-IR), N2 Adsorption-desorption isotherms and BET-specific surface area, thermographic analysis, derivative thermographic analysis (TGA-DTA) and Field emission scanning electron microscopy (FESEM). A fixed-bed reactor was used for the removal of HA and the effects of different experimental parameters such as HDTMA loading levels, HA solution flow rate, solution pH and eluent concentration were investigated. The results indicated that the SMZ bed with HDTMA loading of 75% of external cation exchange capacity (ECEC) at a flow rate of 2 BV/h and pH of 10 showed the greatest enhanced removal efficiency of HA while ethanol solutions (25%v/v) with feed flow rate of 2 BV/h were sufficient for complete regeneration of SMZ and desorption of HA. Measurements of surface area of SMZ indicated that a monolayer formation of the surfactant at those conditions allowed the optimum removal of HA.

  7. Utilization of fly ash-derived HZSM-5: catalytic pyrolysis of Jatropha wastes in a fixed-bed reactor.

    PubMed

    Vichaphund, S; Sricharoenchaikul, V; Atong, D

    2017-07-01

    Fly ash-derived HZSM-5 catalyst was first applied in the catalytic pyrolysis of Jatropha residues in a semi-continuous fixed-bed reactor. The catalytic performance of HZSM-5 catalysts prepared from chemicals including conventional hydrothermal HZSM-5, Ni/HZSM-5 by ion exchange, and commercial HZSM-5 (Si/Al = 30) was evaluated for comparison. Catalytic pyrolysis of Jatropha residues with HZSM-5 catalysts was investigated in terms of product yields and qualities of bio-oil and bio-char. The liquid yield produced from fly ash-derived HZSM-5 was 29.4%, which was comparable to those obtained from chemicals and commercial (30.2-32.2%). Fly ash-derived HZSM-5 had high efficiency in increasing desirable compounds such as aliphatics and phenols as well as decreasing oxygenates and particularly N-containing compounds in bio-oils. The higher heating values and pH value of catalytic bio-oil achieved from fly ash-derived HZSM-5 were comparable to those achieved from HZSM-5 prepared from chemicals and commercial. The bio-char had 48-50 wt% carbon and was classified as mesoporous material. Overall, HZSM-5 derived from fly ash showed potentials to use as a catalyst for catalytic pyrolysis application.

  8. Start-up performance of Anammox process in a fixed bed reactor (FBR) filled with honeycomb-like polypropylene carriers.

    PubMed

    Wang, Tao; Shen, Boxiong; Zhang, Sha; Wang, Zhiqiang; Tian, Li

    2016-01-01

    Novel honeycomb-like carriers, made of polypropylene, were applied to enhance biomass retention capacity so as to improve Anammox start-up performance in a fixed bed reactor (FBR). The reactor was operated for 3 months. On day 45, Anammox activity appeared. After 61 days' operation, the removal efficiencies of ammonium and nitrite were both over 91% based on 70 mg N L(-1) of the influent ammonium and influent nitrite, indicating that a remarkable Anammox activity was attained. A final specific Anammox activity of 0.12 g NH4(+)-N gVSS(-1) d(-1) was reached (VSS: volatile suspended solids). The FBR showed a good capacity for resisting shock loading and was more able to resist shock loading of nitrogen concentration than resist hydraulic shock loading. Phylogenetic analysis showed that Candidatus Brocadia anammoxidans' and Candidatus Kuenenia stuttgartiensis' were detected in the mature biofilm, and Candidatus Brocadia anammoxidans' was the dominant Anammox strain. Candidatus Kuenenia stuttgartiensis' played a positive role in the reactor performance, as it could consumed nitrite quickly and efficiently so as to avoid an adverse effect of temporary nitrite accumulation. The results showed that the honeycomb-like carriers were suitable for start-up of Anammox.

  9. Cobalt (II) removal from aqueous solutions by natural hemp fibers: Batch and fixed-bed column studies

    NASA Astrophysics Data System (ADS)

    Tofan, Lavinia; Teodosiu, Carmen; Paduraru, Carmen; Wenkert, Rodica

    2013-11-01

    Natural hemp fibers were explored as sorbent for the removal of Co(II) ions from aqueous solutions in batch and dynamic conditions. The batch Co(II) sorption capacity increased up to pH 5, reached the maximum (7.5-7.8 mg/g) over the initial pH of 4.5-5. As the initial concentration of metal ion increased (in the range of 25-200 mg/L), the cobalt uptake was enhanced, but the Co(II) removal efficiency decreased. The batch sorption of Co(II) on the tested hemp follows a pseudo-second order model, which relies on the assumption that the chemisorptions may be the rate-controlling step. The Langmuir model better described the Co(II) sorption process on the natural hemp fibers in comparison with the Freundlich model. This finding complies with the results of fixed-bed studies which emphasize that the optimal solution for describing the behavior of the investigated hemp bed column is provided by the Thomas model. The sorption capacity of the hemp fibers column (15.44 mg/g) performed better than that of the Co(II)-hemp batch system (13.58 mg/g). The possibility to use hemp fibers as an alternative in the Co(II) wastewater treatment should be studied under pilot scale applications, so as to complete the studies concerning the removal efficiencies with technical and economic factors that influence process scale-up.

  10. Biosorption of copper(II) and lead(II) from aqueous solution by chaff in a fixed-bed column.

    PubMed

    Han, Runping; Zhang, Jinghua; Zou, Weihua; Xiao, Huijun; Shi, Jie; Liu, Hongmin

    2006-05-20

    In this article, the ability of chaff to adsorb heavy metal ions from aqueous solution was investigated in a fixed-bed column. The effect of important parameters, such as the value of pH, the flow rate, the influent concentration of solution and the effect of coexistence ions, was studied. Also the adsorption/desorption recycles of chaff were shown, and the results indicated that chaff could be recycled to remove heavy metal ions. The Thomas model was applied to adsorption of copper and lead at different flow rate and different influent concentration to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design. The model was found suitable for describing the biosorption process of the dynamic behavior of the chaff column. All the results suggested that chaff as adsorbent to removal heavy metal ions from solution prove efficient, and the rate of biosorption process is speedy. Furthermore, the efficiency of adsorption is high. When the flow rate was 3.6 ml min(-1) and the influent concentration of copper and lead was 14.82 mg l(-1) and 50.12 mg l(-1) respectively, the equilibrium adsorption biomass reached 1.98 mg g(-1) and 6.72 mg g(-1), respectively. The competitive adsorption for lead and copper was studied. Moreover the total adsorbing capability of chaff did not decrease when there were both copper(II) and lead(II) in solution.

  11. Adsorption of phosphate from aqueous solutions and sewage using zirconium loaded okara (ZLO): Fixed-bed column study.

    PubMed

    Nguyen, T A H; Ngo, H H; Guo, W S; Pham, T Q; Li, F M; Nguyen, T V; Bui, X T

    2015-08-01

    This study explores the potential of removing phosphorus from aqueous solutions and sewage by Zr(IV)-loaded okara (ZLO) in the fixed-bed column. Soybean residue (okara) was impregnated with 0.25M Zr(IV) solution to prepare active binding sites for phosphate. The effect of several factors, including flow rate, bed height, initial phosphorus concentration, pH and adsorbent particle size on the performance of ZLO was examined. The maximum dynamic adsorption capacity of ZLO for phosphorus was estimated to be 16.43mg/g. Breakthrough curve modeling indicated that Adams-Bohart model and Thomas model fitted the experimental data better than Yoon-Nelson model. After treatment with ZLO packed bed column, the effluent could meet the discharge standard for phosphorus in Australia. Successful desorption and regeneration were achieved with 0.2 NaOH and 0.1 HCl, respectively. The results prove that ZLO can be used as a promising phosphorus adsorbent in the dynamic adsorption system.

  12. Fixed-bed column study for hexavalent chromium removal and recovery by short-chain polyaniline synthesized on jute fiber.

    PubMed

    Kumar, Potsangbam Albino; Chakraborty, Saswati

    2009-03-15

    Fixed-bed column studies were conducted to evaluate performance of a short-chain polymer, polyaniline, synthesized on the surface of jute fiber (PANI-jute) for the removal of hexavalent chromium [Cr(VI)] in aqueous environment. Influent pH, column bed depth, influent Cr(VI) concentrations and influent flow rate were variable parameters for the present study. Optimum pH for total chromium removal was observed as 3 by electrostatic attraction of acid chromate ion (HCrO(4)(-)) with protonated amine group (NH(3)(+)) of PANI-jute. With increase in column bed depth from 40 to 60 cm, total chromium uptake by PANI-jute increased from 4.14 to 4.66 mg/g with subsequent increase in throughput volume from 9.84 to 12.6L at exhaustion point. The data obtained for total chromium removal were well described by BDST equation till 10% breakthrough. Adsorption rate constant and dynamic bed capacity at 10% breakthrough were observed as 0.01 L/mgh and 1069.46 mg/L, respectively. Adsorbed total chromium was recovered back from PANI-jute as non-toxic Cr(III) after ignition with more than 97% reduction in weight, minimizing the problem of solid waste disposal.

  13. Comparative study on pyrolysis of lignocellulosic and algal biomass using a thermogravimetric and a fixed-bed reactor.

    PubMed

    Yuan, Ting; Tahmasebi, Arash; Yu, Jianglong

    2015-01-01

    Pyrolysis characteristics of four algal and lignocellulosic biomass samples were studied by using a thermogravimetric analyzer (TGA) and a fixed-bed reactor. The effects of pyrolysis temperature and biomass type on the yield and composition of pyrolysis products were investigated. The average activation energy for pyrolysis of biomass samples by FWO and KAS methods in this study were in the range of 211.09-291.19kJ/mol. CO2 was the main gas component in the early stage of pyrolysis, whereas H2 and CH4 concentrations increased with increasing pyrolysis temperature. Bio-oil from Chlorellavulgaris showed higher content of nitrogen containing compounds compared to lignocellulosic biomass. The concentration of aromatic organic compounds such as phenol and its derivatives were increased with increasing pyrolysis temperature up to 700°C. FTIR analysis results showed that with increasing pyrolysis temperature, the concentration of OH, CH, CO, OCH3, and CO functional groups in char decreased sharply. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Wastewater treatment train for fixed bed coal gasification. Semi-annual progress report, May 1-October 31, 1980

    SciTech Connect

    Neufeld, R.D.; Muretti, C.; Ali, F.

    1980-12-01

    The objective of this research is to develop a series of procedures that enable wastewater from a stirred fixed bed gasification process to be treated in an environmentally acceptable manner. Experiments are conducted on a laboratory scale using samples of gasifier wastewater. The linkage of processes used include sulfide stripping, pH adjustment followed by free and fixed ammonia removal, pH adjustment for chemical precipitation of organics, and biological treatment in an activated sludge type configuration. The pre-treatment technique employed provides almost 50% organic removal from the wastewater prior to biological processing; with the organics being accumulated into the sludge phase. The interaction of generated sludges with RCRA regulations is the subject of additional research. A series of continuous biological reactors is operational with hydraulic detention times of 1.0 days, and sludge ages in excess of 20 days. A removal in excess of 80% of COD is accomplished by the biological reactors when the wastewater is pre-treated by the manner developed.

  15. GC/MS characterization of condensable tars in the output stream of a stirred fixed-bed gasifier

    SciTech Connect

    Lamey, S.C.; McCaskill, K.B.; Smith, R.R.

    1981-12-01

    The output stream of the stirred fixed-bed gasifier at the Morgantown Energy Technology Center was sampled for total entrained material. A major portion of the entrained material, in addition to particles, is condensable tar that is subsequently removed from the process gas by wet scrubbing. Characterization of the entrained materials, specifically the tar, is important to establish contaminant levels and to evaluate performance of downstream cleanup units. Samples of tars were collected from the process unit in a combined ice, dry ice, and liquid nitrogen sampler and stored in a refrigerator. The tar samples were then separated into asphaltene, neutral oil, tar acid, and base fractions by solvent extraction using toluene, pentane, sulfuric acid, and potassium hydroxide extraction. Characterization of the fractions obtained from these tars include IR, UV, GC, and GC/MS analysis. The mass spectrometer analysis of the various isolates shows that many individual peaks in the gas chromatograph are in fact mixtures that can be readily identified by the mass spectrometer. It was found that many of the species identified in these fractions were members of aromatic homologous series consisting of parent, mono, di, and tri substituted compounds. Compound identification was made by comparison of the data system library and standard reference spectra. This paper will discuss the instrumental approach and limitation of the GC/MS and the results of the characterization studies of entrained hydrocarbons collected from the gasifier stream.

  16. Treatment of toxic industrial wastewater in fluidized and fixed-bed batch reactors with Trametes versicolor: influence of immobilisation.

    PubMed

    Font, X; Caminal, G; Gabarrell, X; Vicent, T

    2006-08-01

    This work presents the results obtained in the treatment of industrial pulp mill wastewater (black liquor) with the white-rot fungus Trametes versicolor immobilised in nylon and polyurethane foam cubes. Reductions in colour (36%), aromatic compounds (54%) and toxicity (3.15 times reduction of the initial value) were obtained when the fungus was immobilised in nylon and good toxicity reduction (5.7-fold reduction of the initial value) when polyurethane foam was used. These results were compared with those obtained with Trametes versicolor in the form of pellets for colour and aromatic compounds (84.8% and 70.2% respectively). Correlations among different parameters have been studied. Relationships between colour and changes in the molecular weight distribution profiles, as well as a correlation between laccase production and toxicity reduction have been found. For laccase production vs. toxicity reduction a different behaviour has been observed depending on the bioreactor configuration (fixed-bed reactor with immobilised Trametes versicolor or fluidised bed reactor with pellets of Trametes versicolor).

  17. Activation of Canadian coals in a fixed-bed reactor: effect of the particle size on product quality

    SciTech Connect

    Ajay K. Dalai; Narayan C. Pradhan; Jian Liu; Amitabha Majumdar; Eric L. Tollefson

    2008-07-15

    Three Canadian coals, namely, Bienfait lignite, Montgomery sub-bituminous C, and Coal Valley high volatile bituminous C were activated in a fixed-bed reactor. For each coal, two different sizes of particles in the ranges of 0-1.25 mm (fines) and 1.25-2.5 mm (granules) along with cylindrical pellets of 3.18 mm in diameter and 7{+-}2 mm long were activated. The qualities of the products were determined by measuring iodine and methylene blue numbers, specific Brunauer-Emmett-Teller (BET) surface areas, bulk densities, and ash contents. The specific surface areas and iodine and methylene blue numbers of bituminous coal products were lower than the values obtained with the lignite and sub-bituminous coals, although the product yields were higher. Products obtained from pellets were found to have superior quality compared to that obtained from fines. The ash content of the feed coal influences the quality of the product activated carbon. It was established that a first-order reaction between steam and coal pellets occurred in the process. The activation energies for the process were also determined. 17 refs., 12 figs., 4 tabs.

  18. Catalytic pyrolysis of Alcea pallida stems in a fixed-bed reactor for production of liquid bio-fuels.

    PubMed

    Aysu, Tevfik

    2015-09-01

    Pyrolysis of Alcea pallida stems was performed in a fixed-bed tubular reactor with and without catalyst at three different temperatures. The effects of pyrolysis parameters including temperature and catalyst on the product yields were investigated. It was found that higher temperature resulted in lower liquid (bio-oil) and solid (bio-char) yields and higher gas yields. Catalysts had different effects on product yields and composition of bio-oils. Liquid yields were increased in the presence of zinc chloride and alumina but decreased with calcium hydroxide, tincal and ulexite. The highest bio-oil yield (39.35%) by weight including aqueous phase was produced with alumina catalyst at 500 °C. The yields of bio-char, bio-oil and gas produced, as well as the compositions of the resulting bio-oils were determined by elemental analysis, TGA, FT-IR and GC-MS. 160 different compounds were identified by GC-MS in the bio-oils obtained at 500 °C.

  19. Wastewater treatment with submerged fixed bed biofilm reactor systems--design rules, operating experiences and ongoing developments.

    PubMed

    Schlegel, S; Koeser, H

    2007-01-01

    Wastewater treatment systems using bio-films that grow attached to a support media are an alternative to the widely used suspended growth activated sludge process. Different fixed growth biofilm reactors are commercially used for the treatment of municipal as well as industrial wastewater. In this paper a fairly new fixed growth biofilm system, the submerged fixed bed biofilm reactor (SFBBR), is discussed. SFBBRs are based on aerated submerged fixed open structured plastic media for the support of the biofilm. They are generally operated without sludge recirculation in order to avoid clogging of the support media and problems with the control of the biofilm. Reactor and process design considerations for these reactors are reviewed. Measures to ensure the development and maintenance of an active biofilm are examined. SFBBRs have been applied successfully to small wastewater treatment plants where complete nitrification but no high degree of denitrification is necessary. For the pre-treatment of industrial wastewater the use of SFBBRs is advantageous, especially in cases of wastewater with high organic loading or high content of compounds with low biodegradability. Performance data from exemplary commercial plants are given. Ongoing research and development efforts aim at achieving a high simultaneous total nitrogen (TN) removal of aerated SFBBRs and at improving the efficiency of TN removal in anoxic SFBBRs.

  20. Biosorption of cobalt(II) with sunflower biomass from aqueous solutions in a fixed bed column and neural networks modelling.

    PubMed

    Oguz, Ensar; Ersoy, Muhammed

    2014-01-01

    The effects of inlet cobalt(II) concentration (20-60 ppm), feed flow rate (8-19 ml/min) and bed height (5-15 cm), initial solution pH (3-5) and particle size (0.25fixed bed columns.

  1. Modification of organo-zeolite surface for the removal of reactive azo dyes in fixed-bed reactors.

    PubMed

    Benkli, Y E; Can, M F; Turan, M; Celik, M S

    2005-01-01

    Modification of zeolite (clinoptilolite) surface with a quaternary amine, hexadecyl trimethyl ammonium bromide (HTAB), to improve the removal efficiency of reactive azo dyes in a zeolite fixed bed was investigated. A series of adsorption tests were conducted to find out the uptake of three types of reactive dyes, i.e. CI Reactive Black 5, Red 239 and Yellow 176. Each run consisted of modifying zeolite with HTAB in the column followed by removal of color from the modified zeolite bed. The breakthrough curves for modification process were constructed under different conditions by plotting the normalized effluent concentration (C/C(0)) versus time or bed volumes (BV). Optimization studies show that 3g/l of HTAB dosage at a flowrate of 0.025l/min showed the best performance. Examination of the dye removal under the optimum modification conditions reveals that the black dye gives the highest breakthrough point among the three dyes tested. This is ascribed to the hydrophobic/hydrophilic match of the zeolite surface with the dye molecule, which depends upon the way zeolite is modified with HTAB. Calculations of the HTAB coverage on zeolite surface indicate that a bilayer formation is the most viable packing that enables maximum removal of the dye.

  2. Application of an isothermal, three-phase catalytic reactor model to predict unsteady-state fixed-bed performance.

    PubMed

    Yang, Ji; Hand, David W; Hokanson, David R; Crittenden, John C

    2003-01-15

    CatReac, a three-phase catalytic mathematical model, was developed for analysis and optimization of the volatile reactor assembly used in International Space Station water processor. This wet oxidation process is used to remove low molecular weight contaminants such as acetic acid, acetone, ethanol, 1-propanol, 2-propanol, and propionic acid, which are not removed by the other treatment processes. The Langmuir-Hinshelwood (Hinshelwood, C. N. The Kinetics of Chemical Change in Gaseous Systems, 3rd ed.; Oxford: London, 1933; pp 301-347) isothermal adsorption expression was successfully used to describe the reaction kinetics of compounds on the catalyst surface for the compounds mentioned above. Small-column experiments combined with the use of the Arrhenius equation were successfully used to predict the Langmuir-Hinshelwood parameters under different temperatures for a temperature range from 93 to 149 degrees C. Full-scale and small-column experiments were successfully used to validate the model predictions for unsteady-state fixed-bed operations.

  3. Continuous methane fermentation and the production of vitamin B12 in a fixed-bed reactor packed with loofah.

    PubMed

    Yang, Yingnan; Zhang, Zhenya; Lu, Jun; Maekawa, Takaaki

    2004-05-01

    A fixed-bed reactor with acclimated methanogens immobilized on a loofah support was studied on a laboratory scale to evaluate the system producing methane from the mixture of CO(2) and H(2) gas, with the production of vitamin B(12) as a by-product. Fermentation using CO(2)/H(2) acclimated methanogens was conducted in a jar fermentor with hydraulic retention times (HRTs) of three and six days. The performance of the reactor was mainly dependent on the HRT. With an HRT of three days, the methane production rate and the vitamin B(12) concentration in the culture broth were 6.18 l/l-reactor/h and 2.88 mg/l-culture liquid; these values were 11.96 l/l-reactor/h and 37.54 mg/l-culture liquid for an HRT of six days. A higher total cell mass of methanogens retained 42.5 g dry cell/l-culture liquid was achieved in the HRT of six days. The loofah carrier immobilized almost 95% of the methanogens, which led to a more effective bio-reaction. It was also observed that the fermentation system had a better ability to buffer pH, especially for an HRT of six days.

  4. Comparison between a moving bed bioreactor and a fixed bed bioreactor for biological phosphate removal and denitrification.

    PubMed

    Choi, H J; Lee, A H; Lee, S M

    2012-01-01

    Moving bed bioreactors (MBBR) and fixed bed bioreactors (FBBR) were compared for biological phosphorus removal and denitrification. The sorption denitrification P-elimination (S-DN-P) process was selected for this study. Results indicated that all nutrients were removed by the FBBR process compared with the MBBR process: 19.8% (total COD), 35.5% (filtered COD), 27.6% (BOD(5)), 62.2% (acetate), 78.5% (PO(4)-P), and 54.2% (NO(3)-N) in MBBR; 49.7% (total COD), 54.0% (filtered COD), 63.2% (BOD(5)), 99.6% (acetate), 98.6% (PO(4)-P), and 75.9% (NO(3)-N) in FBBR. The phosphate uptake and NO(3)-N decomposition in the FBBR process during the denitrification phase were much higher than for the MBBR process despite being of shorter duration. Results obtained from this study are helpful in elucidating the practical implications of using MBBR and FBBR for the removal of bio-P and denitrification from wastewater.

  5. Biological removal of organic constituents in quench water from a slagging, fixed-bed coal-gasification pilot plant

    SciTech Connect

    Stamoudis, V C; Luthy, R G

    1980-02-01

    This study is part of an effort to assess the efficiency of activated-sludge treatment for removal of organic constituents from high-Btu coal-gasification pilot-plant quench waters. A sample of raw-gas quench water was obtained from the Grand Forks Energy and Technology Center's pilot plant, which employs the slagging, fixed-bed gasification process. The quench water generated in the processing of Indian Head lignite was pretreated to reduce ammonia and alkalinity, and then diluted and subjected to long-term biological treatment, followed by detailed characterization and analysis of organic constituents. The pretreated (influent) and treated (effluent) samples were extracted using a methylene chloride, pH-fractionation method to obtain acid, base, and neutral fractions, which were analyzed by capillary-column gas chromatography/mass spectrometry (GC/MS). Over 99% of the total extractable and chromatographable organic material in the influent acid fraction was composed of phenol and alkylated phenols. Biological treatment removed these compounds almost completely. Major components of the influent base fraction were alkylated pyridines, anilines, aminopyrroles, imidazoles and/or pyrazoles, diazines, and quinolines. Removal efficiency of these compounds ranged between 90 and 100%. The influent neutral fraction was composed mainly of cycloalkanes, cycloalkenes, naphthalene, indole, acetophenone, and benzonitrile. Alkylated benzenes were generally absent. Removal efficiencies of these compounds were generally very good, except for certain alkylated cycloalkanes and cycloalkenes. Results are compared with those of a similar study on HYGAS coal-gasification quench water.

  6. Degradation of p-nitrophenol in aqueous solution by microwave assisted oxidation process through a granular activated carbon fixed bed.

    PubMed

    Bo, Longli; Quan, Xie; Chen, Shuo; Zhao, Huimin; Zhao, Yazhi

    2006-09-01

    A microwave (MW) assisted oxidation process was investigated for degradation of p-nitrophenol (PNP) from aqueous solution. The process consisted of a granular activated carbon (GAC) fixed bed reactor, a MW source, solution and air supply system, and a heat exchanger. The process was operated in continuous flow mode. Air was applied for oxygen supply. GAC acted as a MW energy absorption material as well as the catalyst for PNP degradation. MW power, air flow, GAC dose, and influent flow proved to be major factors which influenced PNP degradation. The results showed that PNP was degraded effectively by this new process. Under a given condition (PNP concentration 1330mg/L, MW power 500 W, influent flow 6.4 mL/min, air flow 100 mL/min), PNP removed 90%, corresponding to 80% of TOC removal. The pathway of PNP degradation was deduced based on GC-MS identification of course products. PNP experienced sequential oxidation steps and mineralized ultimately. Nitro-group of PNP converted to nitrite and nitrate. Biodegradability of the solution was improved apparently after treatment by MW assisted oxidation process, which benefit to further treatment of the solution using biochemical method.

  7. A continuous process for biodiesel production in a fixed bed reactor packed with cation-exchange resin as heterogeneous catalyst.

    PubMed

    Feng, Yaohui; Zhang, Aiqing; Li, Jianxin; He, Benqiao

    2011-02-01

    Continuous esterification of free fatty acids (FFA) from acidified oil with methanol was carried out with NKC-9 cation-exchange resin in a fixed bed reactor with an internal diameter of 25 mm and a height of 450 mm to produce biodiesel. The results showed that the FFA conversion increased with increases in methanol/oil mass ratio, reaction temperature and catalyst bed height, whereas decreased with increases in initial water content in feedstock and feed flow rate. The FFA conversion kept over 98.0% during 500 h of continuous esterification processes under 2.8:1 methanol to oleic acid mass ratio, 44.0 cm catalyst bed height, 0.62 ml/min feed flow rate and 65°C reaction temperature, showing a much high conversion and operational stability. Furthermore, the loss of sulfonic acid groups from NKC-9 resin into the production was not found during continuous esterification. In sum, NKC-9 resin shows the potential commercial applications to esterification of FFA. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. Robust regulation of anaerobic digestion processes.

    PubMed

    Mailleret, L; Bernard, O; Steyer, J P

    2003-01-01

    This paper deals with the problem of controlling anaerobic digestion processes. A two-step (i.e. acidogenesis-methanization) mass balance model is considered for a 1 m3 fixed bed digester treating industrial wine distillery wastewater. The control law aims at regulating the organic pollution level while avoiding washout of biomass. To this end, a simple output feedback controller is considered which regulates a variable strongly related to the Chemical Oxygen Demand (COD). Numerical simulations assuming noisy measurements first illustrate the robustness of this control procedure. Then, the regulating procedure is implemented on the considered anaerobic digestion process in order to validate and demonstrate its efficiency in real life experiments.

  9. Efficiency influence of exogenous betaine on anaerobic sequencing batch biofilm reactor treating high salinity mustard tuber wastewater.

    PubMed

    He, Qiang; Kong, Xiang-Juan; Chai, Hong-Xiang; Fan, Ming-Yu; Du, Jun

    2012-01-01

    When treating a composite mustard tuber wastewater with high concentrations of salt (about 20 g Cl(-) L(-1)) and organics (about 8000 mg L(-1) COD) by an anaerobic sequencing batch biofilm reactor (ASBBR) in winter, both high salinity and low temperature will inhibit the activity of anaerobic microorganisms and lead to low treatment efficiency. To solve this problem, betaine was added to the influent to improve the activity of the anaerobic sludge, and an experimental study was carried to investigate the influence of betaine on treating high salinity mustard tuber wastewater by the ASBBR. The results show that, when using anaerobic acclimated sludge in the ASBBR, and controlling biofilm density at 50% and water temperature at 8-12 degrees C, the treatment efficiency of the reactor could be improved by adding the betaine at different concentrations. The efficiency reached the highest when the optimal dosage ofbetaine was 0.5 mmol L(-1). The average effluent COD, after stable acclimation, was 4461 mg L(-1). Relative to ASBBR without adding betaine, the activity of the sludge increased significantly. Meanwhile, the dehydrogenase activity of anaerobic microorganisms and the COD removal efficiency were increased by 18.6% and 18.1%, respectively.

  10. Metabolic sequences of anaerobic fermentation on glucose-based feeding substrates based on correlation analyses of microbial and metabolite profiling.

    PubMed

    Date, Yasuhiro; Iikura, Tomohiro; Yamazawa, Akira; Moriya, Shigeharu; Kikuchi, Jun

    2012-12-07

    Degradation processes in various biomasses are managed by complex metabolic dynamics created by diverse and extensive interactions and competition in microbial communities and their environments. It is important to develop visualization methods to provide a bird's-eye view when characterizing the entire sequential metabolic process in an environmental ecosystem. Here, we describe an approach for the visualization of the metabolic sequences in anaerobic fermentation ecosystems, characterizing the entire metabolic dynamics using a combination of microbial community profiles and metabolic profiles. By evaluating their time-dependent variation, we found that microbial community profiles and metabolite production processes were characteristically affected by the feeding of different glucose-based substrates (glucose, starch, cellulose), although the compositions of the major microbial community and the metabolites detected were likely to be similar in all experiments. This combinatorial approach to variation in microbial communities and metabolic profiles was used successfully to visualize metabolic sequences in anaerobic fermentation ecosystems, in addition to mining candidate microbiota for cellulose degradation. Thus, this approach provides a powerful tool for visualizing and evaluating metabolic sequences within the biomass degradation process in an environmental ecosystem. This is the first report to visualize the entire metabolic dynamic in an anaerobic fermentation ecosystem as metabolic sequences.

  11. Genome sequence and description of the anaerobic lignin-degrading bacterium Tolumonas lignolytica sp. nov.

    SciTech Connect

    Billings, Andrew F.; Fortney, Julian L.; Hazen, Terry C.; Simmons, Blake; Davenport, Karen W.; Goodwin, Lynne; Ivanova, Natalia; Kyrpides, Nikos C.; Mavromatis, Konstantinos; Woyke, Tanja; DeAngelis, Kristen M.

    2015-11-19

    Tolumonas lignolytica BRL6-1T sp. nov. is the type strain of T. lignolytica sp. nov., a proposed novel species of the Tolumonas genus. This strain was isolated from tropical rainforest soils based on its ability to utilize lignin as a sole carbon source. Cells of Tolumonas lignolytica BRL6-1T are mesophilic, non-spore forming, Gram-negative rods that are oxidase and catalase negative. The genome for this isolate was sequenced and returned in seven unique contigs totaling 3.6Mbp, enabling the characterization of several putative pathways for lignin breakdown. Particularly, we found an extracellular peroxidase involved in lignin depolymerization, as well as several enzymes involved in β-aryl ether bond cleavage, which is the most abundant linkage between lignin monomers. We also found genes for enzymes involved in ferulic acid metabolism, which is a common product of lignin breakdown. Finally, by characterizing pathways and enzymes employed in the bacterial breakdown of lignin in anaerobic environments, this work should assist in the efficient engineering of biofuel production from lignocellulosic material.

  12. Genome sequence and description of the anaerobic lignin-degrading bacterium Tolumonas lignolytica sp. nov.

    DOE PAGES

    Billings, Andrew F.; Fortney, Julian L.; Hazen, Terry C.; ...

    2015-11-19

    Tolumonas lignolytica BRL6-1T sp. nov. is the type strain of T. lignolytica sp. nov., a proposed novel species of the Tolumonas genus. This strain was isolated from tropical rainforest soils based on its ability to utilize lignin as a sole carbon source. Cells of Tolumonas lignolytica BRL6-1T are mesophilic, non-spore forming, Gram-negative rods that are oxidase and catalase negative. The genome for this isolate was sequenced and returned in seven unique contigs totaling 3.6Mbp, enabling the characterization of several putative pathways for lignin breakdown. Particularly, we found an extracellular peroxidase involved in lignin depolymerization, as well as several enzymes involvedmore » in β-aryl ether bond cleavage, which is the most abundant linkage between lignin monomers. We also found genes for enzymes involved in ferulic acid metabolism, which is a common product of lignin breakdown. Finally, by characterizing pathways and enzymes employed in the bacterial breakdown of lignin in anaerobic environments, this work should assist in the efficient engineering of biofuel production from lignocellulosic material.« less

  13. Contribution of microfiltration on phosphorus removal in the sequencing anoxic/anaerobic membrane bioreactor.

    PubMed

    Cho, Jinwoo; Song, Kyung-Guen; Ahn, Kyu-Hong

    2009-08-01

    This study investigated the contribution of microfiltration to phosphorus removal in the sequencing anoxic/anaerobic membrane bioreactor. The phosphorus content in activated sludge was fractionated by the Schmidt-Thannhauser-Schneider method. The size distribution of phosphorus in the influent was analyzed to estimate the portion of particulate phosphorus rejected physically by the 0.2 mum microfiltration. The result was that along with the high removal of phosphorus (83%) the phosphorus content of activated sludge was measured as 58.66 mgP/gVSS corresponding to 5.87% on dry weight basis. About 9% of total phosphorus was chemically precipitated phosphates while 56% was stored inside the microbial cell by activity of PAOs, and 35% was the sum of minor intracellular compositions and the particulate residuals, which could be rejected completely by the microfiltration. The biological activity is the dominant way of phosphorus removal in the process. However, the microfiltration also contributed significantly to phosphorus removal by retaining the particulate phosphorus inside the system.

  14. Lactic acid production from potato peel waste by anaerobic sequencing batch fermentation using undefined mixed culture.

    PubMed

    Liang, Shaobo; McDonald, Armando G; Coats, Erik R

    2015-11-01

    Lactic acid (LA) is a necessary industrial feedstock for producing the bioplastic, polylactic acid (PLA), which is currently produced by pure culture fermentation of food carbohydrates. This work presents an alternative to produce LA from potato peel waste (PPW) by anaerobic fermentation in a sequencing batch reactor (SBR) inoculated with undefined mixed culture from a municipal wastewater treatment plant. A statistical design of experiments approach was employed using set of 0.8L SBRs using gelatinized PPW at a solids content range from 30 to 50 g L(-1), solids retention time of 2-4 days for yield and productivity optimization. The maximum LA production yield of 0.25 g g(-1) PPW and highest productivity of 125 mg g(-1) d(-1) were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L(-1) solids content) at the 3 L scale was employed and the highest LA yield of 0.14 g g(-1) PPW and a productivity of 138 mg g(-1) d(-1) were achieved with a 1 d SRT. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Fixed Bed Biomass Gasifier

    SciTech Connect

    Carl Bielenberg

    2006-03-31

    The report details work performed by Gazogen to develop a novel biomass gasifier for producimg electricity from commercially available hardwood chips. The research conducted by Gazogen under this grant was intended to demonstrate the technical and economic feasibility of a new means of producing electricity from wood chips and other biomass and carbonaceous fuels. The technical feasibility of the technology has been furthered as a result of the DOE grant, and work is expected to continue. The economic feasibility can only be shown when all operational problems have been overocme. The technology could eventually provide a means of producing electricity on a decentralized basis from sustainably cultivated plants or plant by-products.

  16. Continuous adsorption of Pb(II) and methylene blue by engineered graphite oxide coated sand in fixed-bed column

    NASA Astrophysics Data System (ADS)

    Gong, Ji-Lai; Zhang, Yong-Liang; Jiang, Yan; Zeng, Guang-Ming; Cui, Zhi-Hui; Liu, Ke; Deng, Can-Hui; Niu, Qiu-Ya; Deng, Jiu-Hua; Huan, Shuang-Yan

    2015-03-01

    The mixture of several effluents, caused by the improper handling and management of effluents, generated multi-component wastewater containing both metals and dyes, leading to the complicated treatment process. In this study, a continuous adsorption of Pb(II) and methylene blue (MB) has been studied in single and binary solutions by using graphite oxide coated sand (GO-sand) as an adsorbent in a fixed-bed column. GO-sand was analyzed by X-ray photoelectron spectroscopy before and after analyte adsorption. Compared with sand filter, adsorption quantity and capacity for Pb(II) and MB by GO-sand filter were greatly increased. In Pb(II) and MB single solutions, the experimental parameters were investigated in detail including initial concentration, flow rate, bed depth and pH. Exhaustion time decreased with increasing initial concentration and flow rate, and increased with increasing bed depth and pH. In the Pb(II)-MB binary solution, exhaustion time significantly decreased for Pb(II) adsorption, but increased for MB adsorption. The reason was explained that the more favorable adsorption for MB onto the surface of GO-sand than that for Pb(II), which was derived from π-π interaction between MB and GO on sand surface in packed filter. The Yoon-Nelson model was applied at different concentration of Pb(II) and MB to predict the breakthrough curves. The experimental data were well fit with the model indicating that it was suitable for this column design.

  17. Incorporation of alpha-Ketoglutaric Acid as a Fixed Bed Scrubber Media for the Neutralization of Hydrazine Family Hypergolic Fuels

    NASA Technical Reports Server (NTRS)

    DeVor, R. W.; Santiago-Maldonado, E.; Parkerson, J. K.

    2010-01-01

    A candidate scrubber media, alpha-ketoglutaric acid (aKGA) adsorbed onto a silica-based substrate was examined as a potential alternative to the hydrazine-family hypergolic fuel neutralization techniques currently utilized at NASA/Kennedy Space Center (KSC). Helvenson et. al. has indicated that aKGA will react with hydrazines to produce non-hazardous, possibly biodegradable products. Furthermore, the authors have previously tested and demonstrated the use of aKGA aqueous solutions as a replacement neutralizing agent for citric acid, which is currently used as a scrubbing agent in liquid scrubbers at KSC. Specific properties examined include reaction efficiency, the loading capacity of aKGA onto various silica substrates, and the comparison of aKGA media performance to that of the citric acid vapor scrubber systems at KSC and a commercial vapor scrubber media. Preliminary investigations showed hydrophobic aerogel particles to be an ideal substrate for the deposition of the aKGA. Current studies have shown that the laboratory produced aKGA-Aerogel absorbent media are more efficient and cost effective than a commercially available fixed bed scrubber media, although much less cost effective than liquid-based citric acid scrubbers (although possibly safer and less labor intensive). A comparison of all three alternative scrubber technologies (liquid aKGA, solid-phase aKGA, and commercially available sorbent materials) is given considering both hypergolic neutralization capabilities and relative costs (as compared to the current citric acid scrubbing technology in use at NASA/KSC).

  18. Batch and fixed-bed adsorption of tartrazine azo-dye onto activated carbon prepared from apricot stones

    NASA Astrophysics Data System (ADS)

    Albroomi, H. I.; Elsayed, M. A.; Baraka, A.; Abdelmaged, M. A.

    2017-07-01

    This work describes the potential of utilizing prepared activated carbon from apricot stones as an efficient adsorbent material for tartrazine (TZ) azo-dye removal in a batch and dynamic adsorption system. The results revealed that activated carbons with well-developed surface area (774 m2/g) and pore volume (1.26 cm3/g) can be manufactured from apricot stones by H3PO4 activation. In batch experiments, effects of the parameters such as initial dye concentration and temperature on the removal of the dye were studied. Equilibrium was achieved in 120 min. Adsorption capacity was found to be dependent on the initial concentration of dye solution, and maximum adsorption was found to be 76 mg/g at 100 mg/L of TZ. The adsorption capacity at equilibrium ( q e) increased from 22.6 to 76 mg/g with an increase in the initial dye concentrations from 25 to 100 mg/L. The thermodynamic parameters such as change in free energy (Δ G 0), enthalpy (Δ H 0) and entropy (Δ S 0) were determined and the positive value of (Δ H) 78.1 (K J mol-1) revealed that adsorption efficiency increased with an increase in the process temperature. In fixed-bed column experiments, the effect of selected operating parameters such as bed depth, flow rate and initial dye concentration on the adsorption capacity was evaluated. Increase in bed height of adsorption columns leads to an extension of breakthrough point as well as the exhaustion time of adsorbent. However, the maximum adsorption capacities decrease with increases of flow rate. The breakthrough data fitted well to bed depth service time and Thomas models with high coefficient of determination, R 2 ≥ 94.

  19. Electrochemical treatment of water containing Microcystis aeruginosa in a fixed bed reactor with three-dimensional conductive diamond anodes.

    PubMed

    Mascia, Michele; Monasterio, Sara; Vacca, Annalisa; Palmas, Simonetta

    2016-12-05

    An electrochemical treatment was investigated to remove Microcystis aeruginosa from water. A fixed bed reactor in flow was tested, which was equipped with electrodes constituted by stacks of grids electrically connected in parallel, with the electric field parallel to the fluid flow. Conductive diamond were used as anodes, platinised Ti as cathode. Electrolyses were performed in continuous and in batch recirculated mode with flow rates corresponding to Re from 10 to 160, current densities in the range 10-60Am(-2) and Cl(-) concentrations up to 600gm(-3). The absorbance of chlorophyll-a pigment and the concentration of products and by-products of electrolysis were measured. In continuous experiments without algae in the inlet stream, total oxidants concentrations as equivalent Cl2, of about 0.7gCl2m(-3) were measured; the maximum values were obtained at Re=10 and i=25Am(-2), with values strongly dependent on the concentration of Cl(-). The highest algae inactivation was obtained under the operative conditions of maximum generation of oxidants; in the presence of microalgae the oxidants concentrations were generally below the detection limit. Results indicated that most of the bulk oxidants electrogenerated is constituted by active chlorine. The prevailing mechanism of M. aeruginosa inactivation is the disinfection by bulk oxidants. The experimental data were quantitatively interpreted through a simple plug flow model, in which the axial dispersion accounts for the non-ideal flow behaviour of the system; the model was successfully used to simulate the performances of the reactor in the single-stack configuration used for the experiments and in multi-stack configurations. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Thin-film fixed-bed reactor for solar photocatalytic inactivation of Aeromonas hydrophila: influence of water quality.

    PubMed

    Khan, Sadia J; Reed, Robert H; Rasul, Mohammad G

    2012-11-29

    Controlling fish disease is one of the major concerns in contemporary aquaculture. The use of antibiotics or chemical disinfection cannot provide a healthy aquaculture system without residual effects. Water quality is also important in determining the success or failure of fish production. Several solar photocatalytic reactors have been used to treat drinking water or waste water without leaving chemical residues. This study has investigated the impact of several key aspects of water quality on the inactivation of the pathogenic bacterium Aeromonas hydrophila using a pilot-scale thin-film fixed-bed reactor (TFFBR) system. The level of inactivation of Aeromonas hydrophila ATCC 35654 was determined using a TFFBR with a photocatalytic area of 0.47 m(2) under the influence of various water quality variables (pH, conductivity, turbidity and colour) under high solar irradiance conditions (980-1100 W m(-2)), at a flow rate of 4.8 L h(-1) through the reactor. Bacterial enumeration were obtained through conventional plate count using trypticase soy agar media, cultured in conventional aerobic conditions to detect healthy cells and under ROS-neutralised conditions to detect both healthy and sub-lethally injured (oxygen-sensitive) cells. The results showed that turbidity has a major influence on solar photocatalytic inactivation of A. hydrophila. Humic acids appear to decrease TiO(2) effectiveness under full sunlight and reduce microbial inactivation. pH in the range 7-9 and salinity both have no major effect on the extent of photoinactivation or sub-lethal injury. This study demonstrates the effectiveness of the TFFBR in the inactivation of Aeromonas hydrophila under the influence of several water quality variables at high solar irradiance, providing an opportunity for the application of solar photocatalysis in aquaculture systems, as long as turbidity remains low.

  1. Characterisation of Particulate Matter Emitted from Cofiring of Lignite and Agricultural Residues in a Fixed-Bed Combustor

    PubMed Central

    Mantananont, Nattasut; Garivait, Savitri; Patumsawad, Suthum

    2012-01-01

    This study is focused on the emission of fixed bed combustor batch operated. Real-time analyser ELPI (electrical low-pressure impactor) system was used to size-segregated particulate matter emission ranging from 40 nm to 10 μm. The results show that total number concentration were 3.4 × 103, 1.6 × 104, and 1.5 × 105 particles/cm3 · kgfuel, while total mass of particles were 12.2, 8.0, and 6.5 mg/Nm3 · kgfuel for combustion of lignite, rice husk and bagasse, respectively. But it can be noticed that cofiring released more particulate matter. Meanwhile it was found that the effect of ratio of over-fired air to total air supply is more pronounced, since decrease in this ratio, the amount of particles are decreased significantly. For particle size distribution, it can be observed that submicron-sized particles dominate and the most prevailing size is in the range: 50 nm

  2. Batch and fixed-bed adsorption of tartrazine azo-dye onto activated carbon prepared from apricot stones

    NASA Astrophysics Data System (ADS)

    Albroomi, H. I.; Elsayed, M. A.; Baraka, A.; Abdelmaged, M. A.

    2016-02-01

    This work describes the potential of utilizing prepared activated carbon from apricot stones as an efficient adsorbent material for tartrazine (TZ) azo-dye removal in a batch and dynamic adsorption system. The results revealed that activated carbons with well-developed surface area (774 m2/g) and pore volume (1.26 cm3/g) can be manufactured from apricot stones by H3PO4 activation. In batch experiments, effects of the parameters such as initial dye concentration and temperature on the removal of the dye were studied. Equilibrium was achieved in 120 min. Adsorption capacity was found to be dependent on the initial concentration of dye solution, and maximum adsorption was found to be 76 mg/g at 100 mg/L of TZ. The adsorption capacity at equilibrium (q e) increased from 22.6 to 76 mg/g with an increase in the initial dye concentrations from 25 to 100 mg/L. The thermodynamic parameters such as change in free energy (ΔG 0), enthalpy (ΔH 0) and entropy (ΔS 0) were determined and the positive value of (ΔH) 78.1 (K J mol-1) revealed that adsorption efficiency increased with an increase in the process temperature. In fixed-bed column experiments, the effect of selected operating parameters such as bed depth, flow rate and initial dye concentration on the adsorption capacity was evaluated. Increase in bed height of adsorption columns leads to an extension of breakthrough point as well as the exhaustion time of adsorbent. However, the maximum adsorption capacities decrease with increases of flow rate. The breakthrough data fitted well to bed depth service time and Thomas models with high coefficient of determination, R 2 ≥ 94.

  3. Study of Indonesia low rank coal utilization on modified fixed bed gasification for combined cycle power plant

    NASA Astrophysics Data System (ADS)

    Hardianto, T.; Amalia, A. R.; Suwono, A.; Riauwindu, P.

    2015-09-01

    Gasification is a conversion process converting carbon-based solid fuel into gaseous products that have considerable amount of calorific value. One of the carbon-based solid fuel that serves as feed for gasification is coal. Gasification gaseous product is termed as syngas (synthetic gas) that is composed of several different gases. Syngas produced from gasification vary from one process to another, this is due to several factors which are: feed characteristics, operation condition, gasified fluid condition, and gasification method or technology. One of the utilization of syngas is for combined cycle power plant fuel. In order to meet the need to convert carbon-based solid fuel into gaseous fuel for combined cycle power plant, engineering adjustment for gasification was done using related software to create the syngas with characteristics of natural gas that serve as fuel for combined cycle power plant in Indonesia. Feed used for the gasification process in this paper was Indonesian Low Rank Coal and the method used to obtain syngas was Modified Fixed Bed Gasifier. From the engineering adjustment process, the yielded syngas possessed lower heating value as much as 31828.32 kJ/kg in gasification condition of 600°C, 3.5 bar, and steam to feed ratio was 1 kg/kg. Syngas characteristics obtained from the process was used as a reference for the adjustment of the fuel system modification in combined cycle power plant that will have the same capacity with the conversion of the system's fuel from natural gas to syngas.

  4. Batch and fixed-bed assessment of sulphate removal by the weak base ion exchange resin Amberlyst A21.

    PubMed

    Guimarães, Damaris; Leão, Versiane A

    2014-09-15

    This paper investigated sulphate removal from aqueous solutions by Amberlyst A21, a polystyrene weak base ion exchange resin. Both the pH and initial sulphate concentration were observed to strongly affect sorption yields, which were largest in acidic environments. Working under optimum operational conditions, sulphate sorption by Amberlyst A21 was relatively fast and reached equilibrium after 45 min of contact between the solid and liquid phases. Sorption kinetics could be described by either the pseudo-first order (k1=3.05 × 10(-5)s(-1)) or pseudo-second order model (k2=1.67 × 10(-4)s(-1)), and both the Freundlich and Langmuir models successfully fitted the equilibrium data. Sulphate uptake by Amberlyst A21 was a physisorption process (ΔH=-25.06 kJ mol(-1)) that occurred with entropy reduction (ΔS=-0.042 kJ mol(-1)K(-1)). Elution experiments showed that sulphate is easily desorbed (∼ 100%) from the resin by sodium hydroxide solutions at pH 10 or pH 12. Fixed-bed experiments assessed the effects of the initial sulphate concentration, bed height and flow rate on the breakthrough curves and the efficiency of the Amberlyst A21 in the treatment of a real effluent. In all studied conditions, the maximum sulphate loading resin varied between 8 and 40 mg(SO4(2-))mL(resin)(-1). Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Treatment of petroleum refinery wastewater containing heavily polluting substances in an aerobic submerged fixed-bed reactor.

    PubMed

    Vendramel, S; Bassin, J P; Dezotti, M; Sant'Anna, G L

    2015-01-01

    Petroleum refineries produce large amount of wastewaters, which often contain a wide range of different compounds. Some of these constituents may be recalcitrant and therefore difficult to be treated biologically. This study evaluated the capability of an aerobic submerged fixed-bed reactor (ASFBR) containing a corrugated PVC support material for biofilm attachment to treat a complex and high-strength organic wastewater coming from a petroleum refinery. The reactor operation was divided into five experimental runs which lasted more than 250 days. During the reactor operation, the applied volumetric organic load was varied within the range of 0.5-2.4 kgCOD.m(-3).d(-1). Despite the inherent fluctuations on the characteristics of the complex wastewater and the slight decrease in the reactor performance when the influent organic load was increased, the ASFBR showed good stability and allowed to reach chemical oxygen demand, dissolved organic carbon and total suspended solids removals up to 91%, 90% and 92%, respectively. Appreciable ammonium removal was obtained (around 90%). Some challenging aspects of reactor operation such as biofilm quantification and important biofilm constituents (e.g. polysaccharides (PS) and proteins (PT)) were also addressed in this work. Average PS/volatile attached solids (VAS) and PT/VAS ratios were around 6% and 50%, respectively. The support material promoted biofilm attachment without appreciable loss of solids and allowed long-term operation without clogging. Microscopic observations of the microbial community revealed great diversity of higher organisms, such as protozoa and rotifers, suggesting that toxic compounds found in the wastewater were possibly removed in the biofilm.

  6. Adsorption of methylene blue from aqueous solution by jackfruit (Artocarpus heteropyllus) leaf powder: A fixed-bed column study.

    PubMed

    Uddin, Md Tamez; Rukanuzzaman, Md; Khan, Md Maksudur Rahman; Islam, Md Akhtarul

    2009-08-01

    Continuous fixed-bed studies were undertaken to evaluate the efficiency of jackfruit leaf powder (JLP) as an adsorbent for the removal of methylene blue (MB) from aqueous solution under the effect of various process parameters like bed depth (5-10cm), flow rate (30-50mL/min) and initial MB concentrations (100-300mg/L). The pH at point of zero charge (pH(PZC)) of the adsorbent was determined by the titration method and a value of 3.9 was obtained. A FTIR of the adsorbent was done before and after the adsorption to find the potential adsorption sites for interaction with methylene blue molecules. The results showed that the total adsorbed quantities and equilibrium uptake decreased with increasing flow rate and increased with increasing initial MB concentration. The longest breakthrough time and maximum MB adsorption were obtained at pH 10. The results showed that the column performed well at low flow rate. Also, breakthrough time and exhaustion time increased with increasing bed depth. The bed-depth service time (BDST) model and the Thomas model were applied to the adsorption of MB at different bed depths, flow rates, influent concentrations and pH to predict the breakthrough curves and to determine the characteristic parameters of the column that are useful for process design. The two model predictions were in very good agreement with the experimental results at all the process parameters studied indicating that they were very suitable for JLP column design.

  7. Thin-film fixed-bed reactor for solar photocatalytic inactivation of Aeromonas hydrophila: influence of water quality

    PubMed Central

    2012-01-01

    Background Controlling fish disease is one of the major concerns in contemporary aquaculture. The use of antibiotics or chemical disinfection cannot provide a healthy aquaculture system without residual effects. Water quality is also important in determining the success or failure of fish production. Several solar photocatalytic reactors have been used to treat drinking water or waste water without leaving chemical residues. This study has investigated the impact of several key aspects of water quality on the inactivation of the pathogenic bacterium Aeromonas hydrophila using a pilot-scale thin-film fixed-bed reactor (TFFBR) system. Results The level of inactivation of Aeromonas hydrophila ATCC 35654 was determined using a TFFBR with a photocatalytic area of 0.47 m2 under the influence of various water quality variables (pH, conductivity, turbidity and colour) under high solar irradiance conditions (980–1100 W m-2), at a flow rate of 4.8 L h-1 through the reactor. Bacterial enumeration were obtained through conventional plate count using trypticase soy agar media, cultured in conventional aerobic conditions to detect healthy cells and under ROS-neutralised conditions to detect both healthy and sub-lethally injured (oxygen-sensitive) cells. The results showed that turbidity has a major influence on solar photocatalytic inactivation of A. hydrophila. Humic acids appear to decrease TiO2 effectiveness under full sunlight and reduce microbial inactivation. pH in the range 7–9 and salinity both have no major effect on the extent of photoinactivation or sub-lethal injury. Conclusions This study demonstrates the effectiveness of the TFFBR in the inactivation of Aeromonas hydrophila under the influence of several water quality variables at high solar irradiance, providing an opportunity for the application of solar photocatalysis in aquaculture systems, as long as turbidity remains low. PMID:23194331

  8. Propagated fixed-bed mixed-acid fermentation: Part I: Effect of volatile solid loading rate and agitation at high pH.

    PubMed

    Golub, Kristina W; Forrest, Andrea K; Mercy, Kevin L; Holtzapple, Mark T

    2011-11-01

    Countercurrent fermentation is a high performing process design for mixed-acid fermentation. However, there are high operating costs associated with moving solids, which is an integral component of this configuration. This study investigated the effect of volatile solid loading rate (VSLR) and agitation in propagated fixed-bed fermentation, a configuration which may be more commercially viable. To evaluate the role of agitation on fixed-bed configuration performance, continuous mixing was compared with periodic mixing. VSLR was also varied and not found to affect acid yields. However, increased VSLR and liquid retention time did result in higher conversions, productivity, acid concentrations, but lower selectivities. Agitation was demonstrated to be important for this fermentor configuration, the periodically-mixed fermentation had the lowest conversion and yields. Operating at a high pH (∼9) contributed to the high selectivity to acetic acid, which might be industrially desirable but at the cost of lower yield compared to a neutral pH.

  9. Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed

    SciTech Connect

    Sun, Rui; Ismail, Tamer M.; Ren, Xiaohan; Abd El-Salam, M.

    2015-05-15

    Highlights: • The effects of moisture content on the burning process of MSW are investigated. • A two-dimensional mathematical model was built to simulate the combustion process. • Temperature distributions, process rates, gas species were measured and simulated. • The The conversion ratio of C/CO and N/NO in MSW are inverse to moisture content. - Abstract: In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on the combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k–ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW.

  10. Adsorptive removal of fluoride from aqueous medium using a fixed bed column packed with Zr(IV) loaded dried orange juice residue.

    PubMed

    Paudyal, Hari; Pangeni, Bimala; Inoue, Katsutoshi; Kawakita, Hidetaka; Ohto, Keisuke; Alam, Shafiq

    2013-10-01

    The potential of the adsorbent prepared from DOJR marketed as cattle food in Japan was identified as an efficient and low cost adsorbent for fluoride using fixed bed column. DOJR was loaded with Zr(IV) ions to develop active adsorption sites for fluoride. Fluoride adsorption performance of column packed with Zr(IV) loaded DOJR was assessed under variable operating conditions such as Zr(IV) loading temperature, initial fluoride concentration, bed depth, initial pH, and flow rate. Breakthrough curve modeling showed that Thomas and bed depth service time (BDST) models were in good agreement with the experimental data. Application of adsorbent investigated in this study to the treatment of actual waste plating solution containing fluoride ion showed successful removal below acceptable standard in Japan using a fixed bed column, hence, Zr(IV)-DOJR can be expected to be a promising candidate for the treatment waste water containing trace amount of fluoride ion in fixed bed column. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Mussel-inspired Functionalization of Cotton for Nano-catalyst Support and Its Application in a Fixed-bed System with High Performance.

    PubMed

    Xi, Jiangbo; Xiao, Junwu; Xiao, Fei; Jin, Yunxia; Dong, Yue; Jing, Feng; Wang, Shuai

    2016-02-23

    Inspired by the composition of adhesive and reductive proteins secreted by marine mussels, polydopamine (PDA) was used to coat cotton microfiber (CMF), and then acted as reducing agent for the growth of Pd nanoparticles on PDA coated CMF (PDA@CMF) composites. The resultant CMF@PDA/Pd composites were then packed in a column for the further use in fixed-bed system. For the catalysis of the reduction of 4-nitrophenol, the flow rate of the 4-aminophenol solution (0.5 mM) was as high as 60 mL/min. The obtained fixed-bed system even exhibited superior performance to conventional batch reaction process because it greatly facilitated the efficiency of the catalytic fibers. Consequently, its turnover frequency (TOF) was up to 1.587 min(-1), while the TOF in the conventional batch reaction was 0.643 min(-1). The catalytic fibers also showed good recyclability, which can be recycled for nine successive cycles without a loss of activity. Furthermore, the catalytic system based on CMF@PDA/Pd can also be applied for Suzuki coupling reaction with the iodobenzene conversion up to 96.7%. The strategy to prepare CMF@PDA/Pd catalytic fixed bed was simple, economical and scalable, which can also be applied for coating different microfibers and loading other noble metal nanoparticles, was amenable for automated industrial processes.

  12. Mussel-inspired Functionalization of Cotton for Nano-catalyst Support and Its Application in a Fixed-bed System with High Performance

    NASA Astrophysics Data System (ADS)

    Xi, Jiangbo; Xiao, Junwu; Xiao, Fei; Jin, Yunxia; Dong, Yue; Jing, Feng; Wang, Shuai

    2016-02-01

    Inspired by the composition of adhesive and reductive proteins secreted by marine mussels, polydopamine (PDA) was used to coat cotton microfiber (CMF), and then acted as reducing agent for the growth of Pd nanoparticles on PDA coated CMF (PDA@CMF) composites. The resultant CMF@PDA/Pd composites were then packed in a column for the further use in fixed-bed system. For the catalysis of the reduction of 4-nitrophenol, the flow rate of the 4-aminophenol solution (0.5 mM) was as high as 60 mL/min. The obtained fixed-bed system even exhibited superior performance to conventional batch reaction process because it greatly facilitated the efficiency of the catalytic fibers. Consequently, its turnover frequency (TOF) was up to 1.587 min-1, while the TOF in the conventional batch reaction was 0.643 min-1. The catalytic fibers also showed good recyclability, which can be recycled for nine successive cycles without a loss of activity. Furthermore, the catalytic system based on CMF@PDA/Pd can also be applied for Suzuki coupling reaction with the iodobenzene conversion up to 96.7%. The strategy to prepare CMF@PDA/Pd catalytic fixed bed was simple, economical and scalable, which can also be applied for coating different microfibers and loading other noble metal nanoparticles, was amenable for automated industrial processes.

  13. Efficiency and chemical recycling capability of magnetite-rich clay towards Eriochrome Black T remediation in the fixed-bed system.

    PubMed

    Djomgoue, Paul; Woumfo, Emmanuel Djoufac; Kammoe, Astride Lorette; Siewe, Jean Mermoz; Njopwouo, Daniel

    2015-01-01

    The present study investigates a fixed-bed column by using magnetite-rich clay from Cameroon as an adsorbent for the removal of the Eriochrome Black T (EBT) from aqueous solution. The effect of various parameters such as bed depths and EBT concentrations was investigated. The Adams-Bohart, Thomas and Yoon-Nelson models were applied to adsorption under varying experimental conditions to predict the breakthrough curves and to evaluate the model parameters of the fixed-bed column that can be useful for the process design. The column regeneration studies were carried out for three different sorption-desorption cycles using HCl or NaOH solution at 1 M. The 1 M HCl solution was found to have the best bed regeneration capacity and the fixed-bed could be reused for several sorption-desorption cycles. The elution efficiency of EBT, 75 mg L(-1) was greater than 99.1% for all three cycles.

  14. Mussel-inspired Functionalization of Cotton for Nano-catalyst Support and Its Application in a Fixed-bed System with High Performance

    PubMed Central

    Xi, Jiangbo; Xiao, Junwu; Xiao, Fei; Jin, Yunxia; Dong, Yue; Jing, Feng; Wang, Shuai

    2016-01-01

    Inspired by the composition of adhesive and reductive proteins secreted by marine mussels, polydopamine (PDA) was used to coat cotton microfiber (CMF), and then acted as reducing agent for the growth of Pd nanoparticles on PDA coated CMF (PDA@CMF) composites. The resultant CMF@PDA/Pd composites were then packed in a column for the further use in fixed-bed system. For the catalysis of the reduction of 4-nitrophenol, the flow rate of the 4-aminophenol solution (0.5 mM) was as high as 60 mL/min. The obtained fixed-bed system even exhibited superior performance to conventional batch reaction process because it greatly facilitated the efficiency of the catalytic fibers. Consequently, its turnover frequency (TOF) was up to 1.587 min−1, while the TOF in the conventional batch reaction was 0.643 min−1. The catalytic fibers also showed good recyclability, which can be recycled for nine successive cycles without a loss of activity. Furthermore, the catalytic system based on CMF@PDA/Pd can also be applied for Suzuki coupling reaction with the iodobenzene conversion up to 96.7%. The strategy to prepare CMF@PDA/Pd catalytic fixed bed was simple, economical and scalable, which can also be applied for coating different microfibers and loading other noble metal nanoparticles, was amenable for automated industrial processes. PMID:26902657

  15. Artificial neural network (ANN) modeling of adsorption of methylene blue by NaOH-modified rice husk in a fixed-bed column system.

    PubMed

    Chowdhury, Shamik; Saha, Papita Das

    2013-02-01

    In this study, rice husk was modified with NaOH and used as adsorbent for dynamic adsorption of methylene blue (MB) from aqueous solutions. Continuous removal of MB from aqueous solutions was studied in a laboratory scale fixed-bed column packed with NaOH-modified rice husk (NMRH). Effect of different flow rates and bed heights on the column breakthrough performance was investigated. In order to determine the most suitable model for describing the adsorption kinetics of MB in the fixed-bed column system, the bed depth service time (BDST) model as well as the Thomas model was fitted to the experimental data. An artificial neural network (ANN)-based model was also developed for describing the dynamic dye adsorption process. An extensive error analysis was carried out between experimental data and data predicted by the models by using the following error functions: correlation coefficient (R(2)), average relative error, sum of the absolute error and Chi-square statistic test (χ(2)). Results show that with increasing bed height and decreasing flow rate, the breakthrough time was delayed. All the error functions yielded minimum values for the ANN model than the traditional models (BDST and Thomas), suggesting that the ANN model is the most suitable model to describe the fixed-bed adsorption of MB by NMRH. It is also more rational and reliable to interpret dynamic dye adsorption data through a process of ANN architecture.

  16. Intermediary Metabolism in Protists: a Sequence-based View of Facultative Anaerobic Metabolism in Evolutionarily Diverse Eukaryotes

    PubMed Central

    Ginger, Michael L.; Fritz-Laylin, Lillian K.; Fulton, Chandler; Cande, W. Zacheus; Dawson, Scott C.

    2011-01-01

    Protists account for the bulk of eukaryotic diversity. Through studies of gene and especially genome sequences the molecular basis for this diversity can be determined. Evident from genome sequencing are examples of versatile metabolism that go far beyond the canonical pathways described for eukaryotes in textbooks. In the last 2–3 years, genome sequencing and transcript profiling has unveiled several examples of heterotrophic and phototrophic protists that are unexpectedly well-equipped for ATP production using a facultative anaerobic metabolism, including some protists that can (Chlamydomonas reinhardtii) or are predicted (Naegleria gruberi, Acanthamoeba castellanii, Amoebidium parasiticum) to produce H2 in their metabolism. It is possible that some enzymes of anaerobic metabolism were acquired and distributed among eukaryotes by lateral transfer, but it is also likely that the common ancestor of eukaryotes already had far more metabolic versatility than was widely thought a few years ago. The discussion of core energy metabolism in unicellular eukaryotes is the subject of this review. Since genomic sequencing has so far only touched the surface of protist diversity, it is anticipated that sequences of additional protists may reveal an even wider range of metabolic capabilities, while simultaneously enriching our understanding of the early evolution of eukaryotes. PMID:21036663

  17. Intermediary metabolism in protists: a sequence-based view of facultative anaerobic metabolism in evolutionarily diverse eukaryotes.

    PubMed

    Ginger, Michael L; Fritz-Laylin, Lillian K; Fulton, Chandler; Cande, W Zacheus; Dawson, Scott C

    2010-12-01

    Protists account for the bulk of eukaryotic diversity. Through studies of gene and especially genome sequences the molecular basis for this diversity can be determined. Evident from genome sequencing are examples of versatile metabolism that go far beyond the canonical pathways described for eukaryotes in textbooks. In the last 2-3 years, genome sequencing and transcript profiling has unveiled several examples of heterotrophic and phototrophic protists that are unexpectedly well-equipped for ATP production using a facultative anaerobic metabolism, including some protists that can (Chlamydomonas reinhardtii) or are predicted (Naegleria gruberi, Acanthamoeba castellanii, Amoebidium parasiticum) to produce H(2) in their metabolism. It is possible that some enzymes of anaerobic metabolism were acquired and distributed among eukaryotes by lateral transfer, but it is also likely that the common ancestor of eukaryotes already had far more metabolic versatility than was widely thought a few years ago. The discussion of core energy metabolism in unicellular eukaryotes is the subject of this review. Since genomic sequencing has so far only touched the surface of protist diversity, it is anticipated that sequences of additional protists may reveal an even wider range of metabolic capabilities, while simultaneously enriching our understanding of the early evolution of eukaryotes.

  18. CO-FIRING COAL: FEEDLOT AND LITTER BIOMASS (CFB AND CLB) FUELS IN PULVERIZED FUEL AND FIXED BED BURNERS

    SciTech Connect

    Kalyan Annamalai; John Sweeten; Saqib Mukhtar; Ben Thein; Gengsheng Wei; Soyuz Priyadarsan; Senthil Arumugam; Kevin Heflin

    2003-08-28

    Intensive animal feeding operations create large amounts of animal waste that must be safely disposed of in order to avoid environmental degradation. Cattle feedlots and chicken houses are two examples. In feedlots, cattle are confined to small pens and fed a high calorie grain-diet diet in preparation for slaughter. In chicken houses, thousands of chickens are kept in close proximity. In both of these operations, millions of tons of manure are produced every year. The manure could be used as a fuel by mixing it with coal in a 90:10 blend and firing it in an existing coal suspension fired combustion systems. This technique is known as co-firing, and the high temperatures produced by the coal will allow the biomass to be completely combusted. Reburn is a process where a small percentage of fuel called reburn fuel is injected above the NO{sub x} producing, conventional coal fired burners in order to reduce NO{sub x}. The manure could also be used as reburn fuel for reducing NO{sub x} in coal fired plants. An alternate approach of using animal waste is to adopt the gasification process using a fixed bed gasifier and then use the gases for firing in gas turbine combustors. In this report, the cattle manure is referred to as feedlot biomass (FB) and chicken manure as litter biomass (LB). The report generates data on FB and LB fuel characteristics. Co-firing, reburn, and gasification tests of coal, FB, LB, coal: FB blends, and coal: LB blends and modeling on cofiring, reburn systems and economics of use of FB and LB have also been conducted. The biomass fuels are higher in ash, lower in heat content, higher in moisture, and higher in nitrogen and sulfur (which can cause air pollution) compared to coal. Small-scale cofiring experiments revealed that the biomass blends can be successfully fired, and NO{sub x} emissions will be similar to or lower than pollutant emissions when firing coal. Further experiments showed that biomass is twice or more effective than coal when

  19. Cow bones char as a green sorbent for fluorides removal from aqueous solutions: batch and fixed-bed studies.

    PubMed

    Nigri, Elbert M; Cechinel, Maria Alice P; Mayer, Diego A; Mazur, Luciana P; Loureiro, José M; Rocha, Sônia D F; Vilar, Vítor J P

    2017-01-01

    Cow bone char was investigated as sorbent for the defluoridation of aqueous solutions. The cow bone char was characterized in terms of its morphology, chemical composition, and functional groups present on the bone char surface using different analytical techniques: SEM, EDS, N2-BET method, and FTIR. Batch equilibrium studies were performed for the bone chars prepared using different procedures. The highest sorption capacities for fluoride were obtained for the acid washed (q = 6.2 ± 0.5 mg/g) and Al-doped (q = 6.4 ± 0.3 mg/g) bone chars. Langmuir and Freundlich models fitted well the equilibrium sorption data. Fluoride removal rate in batch system is fast in the first 5 h, decreasing after this time until achieving equilibrium due to pore diffusion. The presence of carbonate and bicarbonate ions in the aqueous solution contributes to a decrease of the fluoride sorption capacity of the bone char by 79 and 31 %, respectively. Regeneration of the F-loaded bone char using 0.5 M NaOH solution leads to a sorption capacity for fluoride of 3.1 mg/g in the second loading cycle. Fluoride breakthrough curve obtained in a fixed-bed column presents an asymmetrical S-shaped form, with a slow approach of C/C 0 → 1.0 due to pore diffusion phenomena. Considering the guideline value for drinking water of 1.5 mg F(-)/L, as recommended by World Health Organization, the service cycle for fluoride removal was of 71.0 h ([F(-)]feed ∼ 9 mg/L; flow rate = 1 mL/min; m sorbent = 12.6 g). A mass transfer model considering the pore diffusion was able to satisfactorily describe the experimental data obtained in batch and continuous systems.

  20. Fermentative hydrogen production from liquid swine manure with glucose supplement using an anaerobic sequencing batch reactor

    NASA Astrophysics Data System (ADS)

    Wu, Xiao

    2009-12-01

    The idea of coupling renewable energy production and agricultural waste management inspired this thesis. The production of an important future fuel---hydrogen gas---from high strength waste stream-liquid swine manure---using anaerobic treatment processes makes the most sustainable sense for both wastewater utilization and energy generation. The objectives of this thesis were to develop a fermentation process for converting liquid swine manure to hydrogen and to maximize hydrogen productivity. Anaerobic sequencing batch reactor (ASBR) systems were constructed to carry out this fermentation process, and seed sludge obtained from a dairy manure anaerobic digester and pretreated by nutrient acclimation, heat and pH treatment was used as inoculum. High system stability was indicated by a short startup period of 12 days followed by stable hydrogen production, and successful sludge granulation occurred within 23 days of startup at a hydraulic retention time (HRT) of 24 hours. Operation at a progressively decreasing HRT from 24 to 8h gave rise to an increasing biogas production rate from 15.2-34.4L/d, while good linear relationships were observed between both total biogas and hydrogen production rates correlated to HRT, with R2 values of 0.993 and 0.997, respectively. The maximum hydrogen yield of 1.63 mol-H 2/mol-hexose-feed occurred at HRT of 16h, while the HRT of 12h was highly suggested to achieve both high production rate and efficient yield. Hexose utilization efficiencies over 98%, considerable hydrogen production rate up to 14.3 L/d and hydrogen percentage of off-gas up to 43% (i.e., a CO 2/H2 ratio of 1.2) with the absence of CH4 production throughout the whole course of experiment at a pH of 5.0 strongly validated the feasibility of the fermentative H2 production from liquid swine manure using an ASBR system. Ethanol as well as acetic, butyric and valeric acids were produced in the system accompanying the hydrogen production, with acetic acid being the dominant

  1. First-order kinetics of landfill leachate treatment in a pilot-scale anaerobic sequence batch biofilm reactor.

    PubMed

    Contrera, Ronan Cleber; da Cruz Silva, Katia Cristina; Morita, Dione Mari; Domingues Rodrigues, José Alberto; Zaiat, Marcelo; Schalch, Valdir

    2014-12-01

    This paper reports the kinetics evaluation of landfill leachate anaerobic treatment in a pilot-scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR). The experiment was carried out at room temperature (23.8 ± 2.1 °C) in the landfill area in São Carlos-SP, Brazil. Biomass from the bottom of a local landfill leachate stabilization pond was used as inoculum. After acclimated and utilizing leachate directly from the landfill, the AnSBBR presented efficiency over 70%, in terms of COD removal, with influent COD ranging from 4825 mg L(-1) to 12,330 mg L(-1). To evaluate the kinetics of landfill leachate treatment, temporal profiles of CODFilt. concentration were performed and a first-order kinetics model was adjusted for substrate consumption, obtaining an average k1 = 4.40 × 10(-5) L mgTVS(-1) d(-1), corrected to 25 °C. Considering the temperature variations, a temperature-activity coefficient θ = 1.07 was obtained. Statistical "Randomness" and "F" tests were used to successfully validate the model considered. Thus, the results demonstrate that the first-order kinetic model is adequate to model the anaerobic treatment of the landfill leachate in the AnSBBR.

  2. A comparison of anaerobic 2, 4-dichlorophenoxy acetic acid degradation in single-fed and sequencing batch reactor systems

    NASA Astrophysics Data System (ADS)

    Elefsiniotis, P.; Wareham, D. G.; Fongsatitukul, P.

    2017-08-01

    This paper compares the practical limits of 2, 4-dichlorophenoxy acetic acid (2,4-D) degradation that can be obtained in two laboratory-scale anaerobic digestion systems; namely, a sequencing batch reactor (SBR) and a single-fed batch reactor (SFBR) system. The comparison involved synthesizing a decade of research conducted by the lead author and drawing summative conclusions about the ability of each system to accommodate industrial-strength concentrations of 2,4-D. In the main, 2 L liquid volume anaerobic SBRs were used with glucose as a supplemental carbon source for both acid-phase and two-phase conditions. Volatile fatty acids however were used as a supplemental carbon source for the methanogenic SBRs. The anaerobic SBRs were operated at an hydraulic retention time of 48 hours, while being subjected to increasing concentrations of 2,4-D. The SBRs were able to degrade between 130 and 180 mg/L of 2,4-D depending upon whether they were operated in the acid-phase or two-phase regime. The methanogenic-only phase did not achieve 2,4-D degradation however this was primarily attributed to difficulties with obtaining a sufficiently long SRT. For the two-phase SFBR system, 3.5 L liquid-volume digesters were used and no difficulty was experienced with degrading 100 % of the 2,4-D concentration applied (300 mg/L).

  3. Microbial community analysis of swine wastewater anaerobic lagoons by next-generation DNA sequencing

    USDA-ARS?s Scientific Manuscript database

    Anaerobic lagoons are a standard practice for the treatment of swine wastewater. This practice relies heavily on microbiological processes to reduce concentrated organic material and nutrients. Despite this reliance on microbiological processes, research has only recently begun to identify and enume...

  4. Application Sequence and soil biology influence anaerobic soil disinfestation induced disease suppression

    USDA-ARS?s Scientific Manuscript database

    Anaerobic soil disinfestation (ASD) and mustard seed meal (MSM) soil amendments can yield significant control of a diversity of soil-borne pests and pathogens. The mechanisms functional in disease suppression are diverse and with regard to MSM amendment, soil biology has been shown to have a signif...

  5. CO-FIRING COAL, FEEDLOT, AND LITTER BIOMASS (CFB AND LFB) FUELS IN PULVERIZED FUEL AND FIXED BED BURNERS

    SciTech Connect

    Kalyan Annamalai; John Sweeten; Saqib Mukhtar; Ben Thien; Gengsheng Wei; Soyuz Priyadarsan

    2002-01-15

    result as the levels of N are higher in the biomass fuel than in coal. Further experiments showed that biomass is twice or more effective than coal when used in a reburning process to reduce NO{sub x} emissions. Since crushing costs of biomass fuels may be prohibitive, stoker firing may be cost effective; in order simulate such a firing, future work will investigate the performance of a gasifier when fired with larger sized coal and biomass. It will be a fixed bed gasifier, and will evaluate blends, coal, and biomass. Computer simulations were performed using the PCGC-2 code supplied by BYU and modified by A&M with three mixture fractions for handling animal based biomass fuels in order to include an improved moisture model for handling wet fuels and phosphorus oxidation. Finally the results of the economic analysis show that considerable savings can be achieved with the use of biomass. In the case of higher ash and moisture biomass, the fuel cost savings will be reduced, due to increased transportation costs. A spreadsheet program was created to analyze the fuel savings for a variety of different moisture levels, ash levels, and power plant operating parameters.

  6. Conceptual process design and techno-economic assessment of ex situ catalytic fast pyrolysis of biomass: A fixed bed reactor implementation scenario for future feasibility

    SciTech Connect

    Dutta, Abhijit; Schaidle, Joshua A.; Humbird, David; Baddour, Frederick G.; Sahir, Asad

    2015-10-06

    Ex situ catalytic fast pyrolysis of biomass is a promising route for the production of fungible liquid biofuels. There is significant ongoing research on the design and development of catalysts for this process. However, there are a limited number of studies investigating process configurations and their effects on biorefinery economics. Herein we present a conceptual process design with techno-economic assessment; it includes the production of upgraded bio-oil via fixed bed ex situ catalytic fast pyrolysis followed by final hydroprocessing to hydrocarbon fuel blendstocks. This study builds upon previous work using fluidized bed systems, as detailed in a recent design report led by the National Renewable Energy Laboratory (NREL/TP-5100-62455); overall yields are assumed to be similar, and are based on enabling future feasibility. Assuming similar yields provides a basis for easy comparison and for studying the impacts of areas of focus in this study, namely, fixed bed reactor configurations and their catalyst development requirements, and the impacts of an inline hot gas filter. A comparison with the fluidized bed system shows that there is potential for higher capital costs and lower catalyst costs in the fixed bed system, leading to comparable overall costs. The key catalyst requirement is to enable the effective transformation of highly oxygenated biomass into hydrocarbons products with properties suitable for blending into current fuels. Potential catalyst materials are discussed, along with their suitability for deoxygenation, hydrogenation and C–C coupling chemistry. This chemistry is necessary during pyrolysis vapor upgrading for improved bio-oil quality, which enables efficient downstream hydroprocessing; C–C coupling helps increase the proportion of diesel/jet fuel range product. One potential benefit of fixed bed upgrading over fluidized bed upgrading is catalyst flexibility, providing greater control over chemistry and product composition. Since this

  7. Conceptual process design and techno-economic assessment of ex situ catalytic fast pyrolysis of biomass: A fixed bed reactor implementation scenario for future feasibility

    DOE PAGES

    Dutta, Abhijit; Schaidle, Joshua A.; Humbird, David; ...

    2015-10-06

    Ex situ catalytic fast pyrolysis of biomass is a promising route for the production of fungible liquid biofuels. There is significant ongoing research on the design and development of catalysts for this process. However, there are a limited number of studies investigating process configurations and their effects on biorefinery economics. Herein we present a conceptual process design with techno-economic assessment; it includes the production of upgraded bio-oil via fixed bed ex situ catalytic fast pyrolysis followed by final hydroprocessing to hydrocarbon fuel blendstocks. This study builds upon previous work using fluidized bed systems, as detailed in a recent design reportmore » led by the National Renewable Energy Laboratory (NREL/TP-5100-62455); overall yields are assumed to be similar, and are based on enabling future feasibility. Assuming similar yields provides a basis for easy comparison and for studying the impacts of areas of focus in this study, namely, fixed bed reactor configurations and their catalyst development requirements, and the impacts of an inline hot gas filter. A comparison with the fluidized bed system shows that there is potential for higher capital costs and lower catalyst costs in the fixed bed system, leading to comparable overall costs. The key catalyst requirement is to enable the effective transformation of highly oxygenated biomass into hydrocarbons products with properties suitable for blending into current fuels. Potential catalyst materials are discussed, along with their suitability for deoxygenation, hydrogenation and C–C coupling chemistry. This chemistry is necessary during pyrolysis vapor upgrading for improved bio-oil quality, which enables efficient downstream hydroprocessing; C–C coupling helps increase the proportion of diesel/jet fuel range product. One potential benefit of fixed bed upgrading over fluidized bed upgrading is catalyst flexibility, providing greater control over chemistry and product composition

  8. Draft Genome Sequence of the Type Strain Desulfuribacillus alkaliarsenatis AHT28, an Obligately Anaerobic, Sulfidogenic Bacterium Isolated from Russian Soda Lake Sediments

    PubMed Central

    Abin, Christopher A.

    2016-01-01

    Desulfuribacillus alkaliarsenatis AHT28T is an obligately anaerobic, sulfur- and arsenate-reducing haloalkaliphile that was isolated from Russian soda lake sediments. Here, we present the 3.1-Mb draft genome sequence for this strain, consisting of 36 contigs with a G+C content of 37.5% and 2,978 protein-coding sequences. PMID:27834702

  9. The genome sequence of Desulfatibacillum alkenivorans AK-01: a blueprint for anaerobic alkane oxidation.

    PubMed

    Callaghan, A V; Morris, B E L; Pereira, I A C; McInerney, M J; Austin, R N; Groves, J T; Kukor, J J; Suflita, J M; Young, L Y; Zylstra, G J; Wawrik, B

    2012-01-01

    Desulfatibacillum alkenivorans AK-01 serves as a model organism for anaerobic alkane biodegradation because of its distinctive biochemistry and metabolic versatility. The D. alkenivorans genome provides a blueprint for understanding the genetic systems involved in alkane metabolism including substrate activation, CoA ligation, carbon-skeleton rearrangement and decarboxylation. Genomic analysis suggested a route to regenerate the fumarate needed for alkane activation via methylmalonyl-CoA and predicted the capability for syntrophic alkane metabolism, which was experimentally verified. Pathways involved in the oxidation of alkanes, alcohols, organic acids and n-saturated fatty acids coupled to sulfate reduction and the ability to grow chemolithoautotrophically were predicted. A complement of genes for motility and oxygen detoxification suggests that D. alkenivorans may be physiologically adapted to a wide range of environmental conditions. The D. alkenivorans genome serves as a platform for further study of anaerobic, hydrocarbon-oxidizing microorganisms and their roles in bioremediation, energy recovery and global carbon cycling.

  10. Putting microbes to work in sequence: recent advances in temperature-phased anaerobic digestion processes.

    PubMed

    Lv, Wen; Schanbacher, Floyd L; Yu, Zhongtang

    2010-12-01

    Methane biogas production through anaerobic digestion (or biomethanation) is one of the few technologies that both produce bioenergy and protect the environment. When the focus of anaerobic digestion (AD) is shifted from primarily wastewater treatment to bioenergy production, efficiency and process stability become critical to the economic viability of AD technologies. Temperature-phased anaerobic digestion (TPAD) is a promising process that can significantly enhance both digestion efficiency and process robustness. A TPAD system separates the conventional AD process into two phases, so both phases can be optimized according to their individual functional needs. In the first, thermophilic phase, the often rate-limiting hydrolysis step of polymeric feedstock is accelerated by elevated temperatures, while in the second, mesophilic phase, the fastidious syntrophic acetogens and methanogens are provided with permissive conditions where inhibitions to key guilds (e.g., syntrophic acetogens and methanogens) are attenuated. Although large-scale TPAD systems have not been applied widely, researchers have demonstrated the potential superiority of TPAD systems over single-stage digesters and other AD processes with enhanced VS (volatile solids) and pathogen removal; increased methane yield, process stability, OLR (organic loading rate); shorter HRT (hydraulic retention time); decreased foaming and short-chain fatty acids in effluent. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  11. Complete genome sequence of the bile-resistant pigment-producing anaerobe Alistipes finegoldii type strain (AHN2437(T)).

    PubMed

    Mavromatis, Konstantinos; Stackebrandt, Erko; Munk, Christine; Lapidus, Alla; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Tapia, Roxanne; Goodwin, Lynne A; Pitluck, Sam; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, Natalia; Mikhailova, Natalia; Huntemann, Marcel; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Rohde, Manfred; Gronow, Sabine; Göker, Markus; Detter, John C; Bristow, James; Eisen, Jonathan A; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Woyke, Tanja

    2013-04-15

    Alistipes finegoldii Rautio et al. 2003 is one of five species of Alistipes with a validly published name: family Rikenellaceae, order Bacteroidetes, class Bacteroidia, phylum Bacteroidetes. This rod-shaped and strictly anaerobic organism has been isolated mostly from human tissues. Here we describe the features of the type strain of this species, together with the complete genome sequence, and annotation. A. finegoldii is the first member of the genus Alistipes for which the complete genome sequence of its type strain is now available. The 3,734,239 bp long single replicon genome with its 3,302 protein-coding and 68 RNA genes is part of the G enomic E ncyclopedia of Bacteria and Archaea project.

  12. Complete genome sequence of the bile-resistant pigment- producing anaerobe Alistipes finegoldii type strain (AHN2437T)

    SciTech Connect

    Mavromatis, K; Stackebrandt, Erko; Munk, Christine; Lapidus, Alla L.; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, N; Mikhailova, Natalia; Huntemann, Marcel; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam L; Hauser, Loren John; Rohde, Manfred; Gronow, Sabine; Goker, Markus; Detter, J. Chris; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Woyke, Tanja

    2013-01-01

    Alistipes finegoldii Rautio et al. 2003 is one of five species of Alistipes with a validly pub- lished name: family Rikenellaceae, order Bacteroidetes, class Bacteroidia, phylum Bacteroidetes. This rod-shaped and strictly anaerobic organism has been isolated mostly from human tissues. Here we describe the features of the type strain of this species, together with the complete genome sequence, and annotation. A. finegoldii is the first member of the genus Alistipes for which the complete genome sequence of its type strain is now available. The 3,734,239 bp long single replicon genome with its 3,302 protein-coding and 68 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

  13. Creation of Pd/Al2O3 Catalyst by a Spray Process for Fixed Bed Reactors and Its Effective Removal of Aqueous Bromate.

    PubMed

    Gao, Yu; Sun, Wuzhu; Yang, Weiyi; Li, Qi

    2017-02-02

    Palladium nanoparticles were grown on sub-millimeter activated Al2O3 particle support by spraying H2PdCl4 solution evenly onto the support, followed with a thermal reduction under H2 atmosphere. Compared with its counterpart created by the conventional impregnation method, the Pd/Al2O3 catalyst created by the spray process could enrich the existence of active Pd nanoparticles on the surface of the catalyst support and increase their degree of dispersion, resulting in a much higher activity in the catalytic reduction of bromate in water. The effect of Al2O3 support particle size on the bromate removal rate was also investigated, which demonstrated that smaller support particle size could have higher activity in the catalytic reduction of bromate in water because of its larger exposed surface. This Pd/Al2O3 catalyst could be easily used in the fixed bed reactor due to its large support size and demonstrated excellent stability in the catalytic reduction of bromate in mineral water. This Pd/Al2O3 catalyst also exhibited a good catalytic reduction performance on azo dyes as demonstrated by its effective catalytic hydrogenation of methyl orange. Thus, catalysts prepared by the spray method developed in this work could have the potential to be used in fixed bed reactors for various water treatment practices.

  14. Evaluation of zeolite A for the sorptive removal of Cs+ and Sr2+ ions from aqueous solutions using batch and fixed bed column operations.

    PubMed

    El-Kamash, A M

    2008-03-01

    Zeolite A was chemically synthesized and evaluated, as inorganic ion exchange material, for the removal of cesium and strontium ions from aqueous solutions in both batch and fixed bed column operations. Batch experiments were carried out as a function of pH, initial ion concentration and temperature. Simple kinetic and thermodynamic models have been applied to the rate and isotherm sorption data and the relevant kinetic and thermodynamic parameters were determined from the graphical presentation of these models. Breakthrough data were determined in a fixed bed column at room temperature (298 K) under the effect of various process parameters like bed depth, flow rate and initial ion concentration. The results showed that the total metal ion uptake and the overall bed capacity decreased with increasing flow rate and increased with increasing initial ion concentrations and bed depth. The dynamics of the ion exchange process was modeled by bed depth service time (BDST) model. The sorption rate constants (K) were found to increase with increase in flow rate indicating that the overall system kinetics was dominated by external mass transfer in the initial part of the sorption process in the column.

  15. Creation of Pd/Al2O3 Catalyst by a Spray Process for Fixed Bed Reactors and Its Effective Removal of Aqueous Bromate

    PubMed Central

    Gao, Yu; Sun, Wuzhu; Yang, Weiyi; Li, Qi

    2017-01-01

    Palladium nanoparticles were grown on sub-millimeter activated Al2O3 particle support by spraying H2PdCl4 solution evenly onto the support, followed with a thermal reduction under H2 atmosphere. Compared with its counterpart created by the conventional impregnation method, the Pd/Al2O3 catalyst created by the spray process could enrich the existence of active Pd nanoparticles on the surface of the catalyst support and increase their degree of dispersion, resulting in a much higher activity in the catalytic reduction of bromate in water. The effect of Al2O3 support particle size on the bromate removal rate was also investigated, which demonstrated that smaller support particle size could have higher activity in the catalytic reduction of bromate in water because of its larger exposed surface. This Pd/Al2O3 catalyst could be easily used in the fixed bed reactor due to its large support size and demonstrated excellent stability in the catalytic reduction of bromate in mineral water. This Pd/Al2O3 catalyst also exhibited a good catalytic reduction performance on azo dyes as demonstrated by its effective catalytic hydrogenation of methyl orange. Thus, catalysts prepared by the spray method developed in this work could have the potential to be used in fixed bed reactors for various water treatment practices. PMID:28150716

  16. Pyrolysis of oil-plant wastes in a TGA and a fixed-bed reactor: Thermochemical behaviors, kinetics, and products characterization.

    PubMed

    Chen, Jianbiao; Fan, Xiaotian; Jiang, Bo; Mu, Lin; Yao, Pikai; Yin, Hongchao; Song, Xigeng

    2015-09-01

    Pyrolysis characteristics of four distinct oil-plant wastes were investigated using TGA and fixed-bed reactor coupled with GC. TGA experiments showed that the pyrolysis behaviors were related to biomass species and heating rates. As the heating rate increased, TG and DTG curves shifted to the higher temperatures, and the comprehensive devolatilization index obviously increased. The remaining chars from TGA experiments were higher than those obtained from the fixed-bed experiments. The crack of tars at high temperatures enhanced the formation of non-condensable gases. During the pyrolysis, C-O and CO2 were the major gases. Chars FTIR showed that the functional groups of O-H, C-H(n), C=O, C-O, and C-C gradually disappeared from 400 °C on. The kinetic parameters were calculated by Coats-Redfern approach. The results manifested that the most appropriate pyrolysis mechanisms were the order reaction models. The existence of kinetic compensation effect was evident. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  17. Propagated fixed-bed mixed-acid fermentation: effect of volatile solid loading rate and agitation at near-neutral pH.

    PubMed

    Golub, Kristina W; Golub, Stacey R; Meysing, Daniel M; Holtzapple, Mark T

    2012-11-01

    To increase conversion and product concentration, mixed-acid fermentation can use a countercurrent strategy where solids and liquids pass in opposite directions through a series of fermentors. To limit the requirement for moving solids, this study employed a propagated fixed-bed fermentation, where solids were stationary and only liquid was transferred. To evaluate the role of agitation, continuous mixing was compared with periodic mixing. The periodically mixed fermentation had similar conversion, but lower yield and selectivity. Increasing volatile solid loading rate from 1.5 to 5.1g non-acid volatile solids/(L(liq)·d) and increasing liquid retention time decreased yield, conversion, selectivity, but increased product concentrations. Compared to a previous study at high pH (~9), this study achieved higher performance at near neutral pH (~6.5) and optimal C-N ratios. Compared to countercurrent fermentation, propagated fixed-bed fermentations have similar selectivities and produce similar proportions of acetic acid, but have lower yields, conversion, productivities, and acid concentrations.

  18. Batch and fixed bed adsorption of levofloxacin on granular activated carbon from date (Phoenix dactylifera L.) stones by KOH chemical activation.

    PubMed

    Darweesh, Teeba M; Ahmed, Muthanna J

    2017-03-01

    Granular activated carbon (KAC) was prepared from abundant Phoenix dactylifera L. stones by microwave- assisted KOH activation. The characteristics of KAC were tested by pore analyses, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR). The adsorption behavior of levofloxacin (LEV) antibiotic on KAC with surface area of 817m(2)/g and pore volume of 0.638cm(3)/g were analyzed using batch and fixed bed systems. The equilibrium data collected by batch experiments were well fitted with Langmuir compared to Freundlich and Temkin isotherms. The effect of flow rate (0.5-1.5ml/min), bed height (15-25cm), and initial LEV concentration (75-225mg/l) on the behavior of breakthrough curves was explained. The fixed bed analysis showed the better correlation of breakthrough data by both Thomas and Yoon-Nelson models. High LEV adsorption capacity of 100.3mg/g was reported on KAC, thus being an efficient adsorbent for antibiotic pollutants to protect ecological systems.

  19. Creation of Pd/Al2O3 Catalyst by a Spray Process for Fixed Bed Reactors and Its Effective Removal of Aqueous Bromate

    NASA Astrophysics Data System (ADS)

    Gao, Yu; Sun, Wuzhu; Yang, Weiyi; Li, Qi

    2017-02-01

    Palladium nanoparticles were grown on sub-millimeter activated Al2O3 particle support by spraying H2PdCl4 solution evenly onto the support, followed with a thermal reduction under H2 atmosphere. Compared with its counterpart created by the conventional impregnation method, the Pd/Al2O3 catalyst created by the spray process could enrich the existence of active Pd nanoparticles on the surface of the catalyst support and increase their degree of dispersion, resulting in a much higher activity in the catalytic reduction of bromate in water. The effect of Al2O3 support particle size on the bromate removal rate was also investigated, which demonstrated that smaller support particle size could have higher activity in the catalytic reduction of bromate in water because of its larger exposed surface. This Pd/Al2O3 catalyst could be easily used in the fixed bed reactor due to its large support size and demonstrated excellent stability in the catalytic reduction of bromate in mineral water. This Pd/Al2O3 catalyst also exhibited a good catalytic reduction performance on azo dyes as demonstrated by its effective catalytic hydrogenation of methyl orange. Thus, catalysts prepared by the spray method developed in this work could have the potential to be used in fixed bed reactors for various water treatment practices.

  20. A mass transfer model for the fixed-bed adsorption of ferulic acid onto a polymeric resin: axial dispersion and intraparticle diffusion.

    PubMed

    Davila-Guzman, Nancy E; Cerino-Córdova, Felipe J; Soto-Regalado, Eduardo; Loredo-Cancino, Margarita; Loredo-Medrano, José A; García-Reyes, Refugio B

    2016-08-01

    In this study, amberlite XAD-16 (XAD-16) bed column system was used to remove ferulic acid (FA) from aqueous solutions. Laboratory-scale column experiments were conducted in downflow fixed bed at initial FA concentration of 1 g/L, initial pH 3, and 25°C. The performance of the adsorbent bed under different flow rates (1.3-7.7 mL/min) was studied. The bed utilization efficiency was in the range of 64.64-72.21% at the studied flow rates. A mass transfer model considering both axial dispersion and intraparticle diffusion was developed to predict the breakthrough curves of FA adsorption on XAD-16. This model predicted the experimental data better than Bohart-Adams model and Thomas model, based on the low deviation between predicted and experimental data. The axial dispersion coefficient value varied from 6.45 × 10(-6) to 1.10 × 10(-6) m(2)/s at flow rate from 1.3 to 7.7 mL/min, whereas the intraparticle diffusion coefficient was 1.04 × 10(-10) m(2)/s, being this last resistance the rate-limiting step. In conclusion, axial dispersion and intraparticle diffusion phenomena play the major role in predicting the adsorption of FA onto XAD-16 in fixed-bed columns.

  1. Single and multi-component adsorption of salicylic acid, clofibric acid, carbamazepine and caffeine from water onto transition metal modified and partially calcined inorganic-organic pillared clay fixed beds.

    PubMed

    Cabrera-Lafaurie, Wilman A; Román, Félix R; Hernández-Maldonado, Arturo J

    2015-01-23

    Fixed-beds of transition metal (Co(2+), Ni(2+) or Cu(2+)) inorganic-organic pillared clays (IOCs) were prepared to study single- and multi-component non-equilibrium adsorption of a set of pharmaceutical and personal care products (PPCPs: salicylic acid, clofibric acid, carbamazepine and caffeine) from water. Adsorption capacities for single components revealed that the copper(II) IOCs have better affinity toward salicylic and clofibric acid. However, multi-component adsorption tests showed a considerable decrease in adsorption capacity for the acids and an unusual selectivity toward carbamazepine depending on the transition metal. This was attributed to a combination of competition between PPCPs for adsorption sites, adsorbate-adsorbate interactions, and plausible pore blocking caused by carbamazepine. The cobalt(II) IOC bed that was partially calcined to fractionate the surfactant moiety showcased the best selectivity toward caffeine, even during multi-component adsorption. This was due to a combination of a mildly hydrophobic surface and interaction between the PPCP and cobalt(II). In general, the tests suggest that these IOCs may be a potential solution for the removal of PPCPs if employed in a layered-bed configuration, to take care of families of adsorbates in a sequence that would produce sharpened concentration wavefronts.

  2. Anaerobic-fed and sequencing-batch treatment of sugar-beet processing wastes: a comparative study.

    PubMed

    Alkaya, Emrah; Demirer, Göksel N

    2011-03-01

    The aim of this study was to compare a batch-fed continuously mixed anaerobic reactor (FCMR) with an anaerobic sequencing batch reactor (ASBR), in terms of waste stabilization and methane production treating sugar-beet processing wastewater and beet-pulp simultaneously. A reactor was operated as FCMR, which then was operated as an ASBR by changing operational conditions after the steady-state was reached. Although the hydraulic retention time value of the ASBR configuration was lower (8 days) than that of the FCMR (15 days) and the corresponding organic loading rate (OLR) was higher (0.71 to 1.33 g COD/L x d), increased biomass retention enabled a significant increase in biomethanation for the ASBR configuration. So, methane production yield of 255 +/- 11 mL/g COD-added was increased to 337 +/- 15 mL/g COD-added (32.2% increase in methane yield) when the configuration was changed from FCMR to ASBR. The experimental results indicated that the ASBR configuration, which was applied to sugar-beet processing wastes for the first time, was superior to the FCMR configuration.

  3. Biogas production in an anaerobic sequencing batch reactor by using tequila vinasses: effect of pH and temperature.

    PubMed

    Arreola-Vargas, J; Jaramillo-Gante, N E; Celis, L B; Corona-González, R I; González-Álvarez, V; Méndez-Acosta, H O

    2016-01-01

    In recent years, anaerobic digestion has been recognized as a suitable alternative for tequila vinasses treatment due to its high energy recovery and chemical oxygen demand (COD) removal efficiency. However, key factors such as the lack of suitable monitoring schemes and the presence of load disturbances, which may induce unstable operating conditions in continuous systems, have limited its application at full scale. Therefore, the aim of this work was to evaluate the anaerobic sequencing batch reactor (AnSBR) configuration in order to provide a low cost and easy operation alternative for the treatment of these complex effluents. In particular, the AnSBR was evaluated under different pH-temperature combinations: 7 and 32 °C; 7 and 38 °C; 8 and 32 °C and 8 and 38 °C. Results showed that the AnSBR configuration was able to achieve high COD removal efficiencies (around 85%) for all the tested conditions, while the highest methane yield was obtained at pH 7 and 38 °C (0.29 L/g COD added). Furthermore, high robustness was found in all the AnSBR experiments. Therefore, the full-scale application of the AnSBR technology for the treatment of tequila vinasses is quite encouraging, in particular for small and medium size tequila industries that operate under seasonal conditions.

  4. Identification and sequence analysis of two regulatory genes involved in anaerobic toluene metabolism by strain T1.

    PubMed Central

    Coschigano, P W; Young, L Y

    1997-01-01

    T1 is a denitrifying bacterium isolated for its ability to grow with toluene serving as the sole carbon source. Mutants of this strain that have defects in the toluene utilization pathway have been isolated and have been separated into classes based on growth phenotypes. A cosmid clone has been isolated by complementing the tutB16 (for toluene utilization) mutation. The complementing gene has been localized to a 3.3-kb DNA fragment. An additional open reading frame upstream of the tutB gene has also been identified and is designated tutC. The nucleotide sequence and the predicted amino acid translation of the 6.4-kb DNA fragment that contains these genes are presented. The tutB and tutC gene products of strain T1 have homology to members of the two-component sensor-regulator family and are proposed to play a role in the regulation of toluene metabolic genes of strain T1. To our knowledge, this is the first published report of the isolation of mutants defective in anaerobic aromatic hydrocarbon degradation. Additionally, we report for the first time the cloning of genes involved in an anaerobic aromatic hydrocarbon degradation pathway. PMID:9023943

  5. Methanosarcina domination in anaerobic sequencing batch reactor at short hydraulic retention time.

    PubMed

    Ma, Jingwei; Zhao, Baisuo; Frear, Craig; Zhao, Quanbao; Yu, Liang; Li, Xiujin; Chen, Shulin

    2013-06-01

    The Archaea population of anaerobic sequential batch reactor (ASBR) featuring cycle operations under varying hydraulic retention time (HRT) was evaluated for treating a dilute waste stream. Terminal-Restriction Length Polymorphism and clone libraries for both 16S rRNA gene and mcrA gene were employed to characterize the methanogenic community structure. Results revealed that a Methanosarcina dominated methanogenic community was successfully established when using an ASBR digester at short HRT. It was revealed that both 16S rRNA and mcrA clone library could not provide complete community structure, while combination of two different clone libraries could capture more archaea diversity. Thermodynamic calculations confirmed a preference for the observed population structure. The results both experimentally and theoretically confirmed that Methanosarcina dominance emphasizing ASBR's important role in treating low strength wastewater as Methanosarcina will be more adept at overcoming temperature and shock loadings experienced with treating this type of wastewater.

  6. Complete Genome Sequence of the Intracellular Bacterial Symbiont TC1 in the Anaerobic Ciliate Trimyema compressum.

    PubMed

    Shinzato, Naoya; Aoyama, Hiroaki; Saitoh, Seikoh; Nikoh, Naruo; Nakano, Kazuma; Shimoji, Makiko; Shinzato, Misuzu; Satou, Kazuhito; Teruya, Kuniko; Hirano, Takashi; Yamada, Takanori; Nobu, Masaru K; Tamaki, Hideyuki; Shirai, Yumi; Park, Sanghwa; Narihiro, Takashi; Liu, Wen-Tso; Kamagata, Yoichi

    2016-09-22

    A free-living ciliate, Trimyema compressum, found in anoxic freshwater environments harbors methanogenic archaea and a bacterial symbiont named TC1 in its cytoplasm. Here, we report the complete genome sequence of the TC1 symbiont, consisting of a 1.59-Mb chromosome and a 35.8-kb plasmid, which was determined using the PacBio RSII sequencer.

  7. Removal of PCDD/Fs from flue gas by a fixed-bed activated carbon filter in a hazardous waste incinerator.

    PubMed

    Karademir, Aykan; Bakoglu, Mithat; Taspinar, Fatih; Ayberk, Savas

    2004-02-15

    The adsorption of polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) by activated carbon (AC) was examined in a fixed-bed AC unit in a hazardous waste incinerator (IZAYDAS) in Turkey. Results showed that the removal efficiencies of PCDD/Fs decrease as the chlorination level increases, which was explained by the difference in gas/particle partitioning of the compounds. Since dioxins are tightly adsorbed by activated carbon, other flue gas constituents showed no clear effect on the dioxin removal. Adsorption kinetics indicated that the adsorption of volatile congeners and homologues fits well with Henry's law, possibly due to the higher gaseous fractions, while the correlation was lower for lowly volatile ones. PCDD/F congeners and homologues had a concentration value up to which no adsorption occurred, which could be attributed to the insufficient contact times at the low concentrations.

  8. Study on product distributions and char morphology during rapid co-pyrolysis of platanus wood and lignite in a drop tube fixed-bed reactor.

    PubMed

    Meng, Haiyu; Wang, Shuzhong; Chen, Lin; Wu, Zhiqiang; Zhao, Jun

    2016-06-01

    The rapid co-pyrolytic behavior of platanus wood and Pingzhuang lignite was explored in a drop tube fixed-bed reactor under nitrogen atmosphere. Synergistic effects were evaluated using the deviations between experimental and predicted values of product yields and gas components. Surface morphology of residual chars were also investigated applying the scanning electron microscopy technique (SEM). This study found that the experimental values of gas volume yields were greater than the predicted, and the maximum gas volume yield exhibited with 50% biomass blending ratio at 1000°C. Positive or negative synergistic effects happened in gas components at different blending ratios and temperatures. The SEM results indicated that the differences of char surface morphology were evident. The fractal dimensions of residual chars increased with increasing biomass blending ratio, which may improve their gasification or combustion reactivity. The change in product yields and gas components was attributed to the secondary reactions and tar cracking.

  9. Start-up and long-term operation of the Anammox process in a fixed bed reactor (FBR) filled with novel non-woven ring carriers.

    PubMed

    Wang, Tao; Zhang, Hanmin; Yang, Fenglin; Li, Yifei; Zhang, Guangyi

    2013-04-01

    A novel kind of non-woven ring carriers was used to improve a fixed bed reactor (FBR) as Anammox reactor. The improved FBR was operated for about 1 year. The Anammox activity occurred on day 39. On day 367, the maximum total nitrogen removal rate reached 9.2 kg Nm(-3)d(-1). FISH analysis showed that Anammox bacteria predominated in the mature sludge and accounted for 78% of the total bacteria. Phylogenetic analysis further showed that Candidatus Kuenenia stuttgartiensis occupied 70% of Anammox bacteria, which benefited keeping the stability of Anammox reactor. The FBR was proved to be a suitable reactor for start-up and long-term operation of Anammox process.

  10. Effects of mass-transfer resistance on apparent stability and performance of fixed-bed immobilized enzyme reactors: theory and experiments with immobilized invertase

    SciTech Connect

    Ooshima, H.; Harano, Y.

    1983-01-01

    Taking the hydrolysis of sucrose by invertase immobilized on anion-exchange resin as an example, the effects of mass-transfer resistance on the apparent stability of immobilized enzyme (IME) and the optimal policy for an IME reaction in a fixed-bed reactor have been studied theoretically and experimentally. The following results were obtained: 1) The effect of mass-transfer resistance on the effective deactivation rate of IME is summarized in two parameters concerning the intraparticle diffusion alphap and the interparticle alphaf. 2) At a constant processed amount of raw materials, there exists an optimal flow rate of reaction fluid to enhance the reactor performance while the mass-transfer resistance shifts the optimal point. 3) The intrinsic deactivation rate of IME has been estimated from the relationship between the fractional conversion at the reactor outlet and the operation time. (Refs. 12).

  11. Draft Genome Sequence of Paenibacillus Strain P1XP2, a Polysaccharide-Degrading, Thermophilic, Facultative Anaerobic Bacterium Isolated from a Commercial Bioreactor Degrading Food Waste

    PubMed Central

    Adelskov, Joseph

    2015-01-01

    The analysis of the ~5.8-Mb draft genome sequence of a moderately thermophilic, heterotrophic, facultative anaerobic bacterium, Paenibacillus strain P1XP2, identified genes for enzymes with the potential for degrading complex food wastes, a property consistent with the ecological habitat of the isolate. PMID:25635015

  12. Draft Genome Sequence of Paenibacillus Strain P1XP2, a Polysaccharide-Degrading, Thermophilic, Facultative Anaerobic Bacterium Isolated from a Commercial Bioreactor Degrading Food Waste.

    PubMed

    Adelskov, Joseph; Patel, Bharat K C

    2015-01-29

    The analysis of the ~5.8-Mb draft genome sequence of a moderately thermophilic, heterotrophic, facultative anaerobic bacterium, Paenibacillus strain P1XP2, identified genes for enzymes with the potential for degrading complex food wastes, a property consistent with the ecological habitat of the isolate.

  13. Biodegradation of isopropanol in a three phase fixed bed bioreactor: start up and acclimation using a previously-enriched microbial culture.

    PubMed

    Bustard, M T; Meeyoo, V; Wright, P C

    2001-10-01

    The aerobic biodegradation of high liquid phase concentrations of 2-propanol (IPA) by a previously enriched solvent-tolerant bacterial consortium within a 1.9 l fed-batch three phase fixed bed bioreactor was investigated. Solvent concentrations of up to 7.9 g l(-1) were investigated. Previously enriched solvent-tolerant bacterial cells were immobilised onto porous glass cylinders as a means obioprocess intensification. Bioreactor start-up and acclimation was studied anacetone concentration tracked as an indicator of IPA utilization, as the sole carbon source within a minimal salts medium (MSM). The initial batch treatment of IPA exhibited a biodegradation rate of 0.11 g l(-1) h(-1) prior to biofilm formation Biofilm growth during the second batch treatment was consistent with an increase in metabolic activity and an IPA biodegradation rate of 0.34 g l(-1), followed by a reduction of biodegradation rate to a constant value of 0.078 g l(-1) h(-1) after 650 h. A maximum acetone generation rate of 1.3 g l(-1) h(-1) was obtained during the fourth IPA addition although the maximum acetone biodegradation rate of 0.38 g l(-1) h(-1) was observed during the initial IPA addition. It is proposed that the metabolic lag resulting from switching from alcohol dehydrogenase to acetone carboxylase is a major rate-limiting step in the deep oxidation of IPA to acetone. The results demonstrate the potential of a previously enriched solvent-tolerant bacterial consortium in fixed bed bioreactor systems, for the aerobic treatment of concentrated solvent-containing wastestreams.

  14. Feasibility analysis of color removal from textile dyeing wastewater in a fixed-bed column system by surfactant-modified zeolite (SMZ).

    PubMed

    Ozdemir, Ozgur; Turan, Mustafa; Turan, Abdullah Zahid; Faki, Aysegul; Engin, Ahmet Baki

    2009-07-30

    In this study, the ability of surfactant-modified zeolite (SMZ) to remove color from real textile wastewater was investigated. Tests were performed in a fixed-bed column reactor and the surface of natural zeolite was modified with a quaternary amine surfactant hexadecyltrimethylammonium bromide (HTAB). The zeolite bed that was modified at 1 g L(-1) HTAB concentration and HTAB flow rate of 0.015 L min(-1) showed good performance in removing color. Effects of wastewater color intensity, flow rates and bed heights were also studied. Wastewater was diluted several times in the ratios of 25%, 50% and 75% in order to assess the influence of wastewater strength. The breakthrough curves of the original and diluted wastewaters are dispersed due to the fact that breakthrough came late at lower color intensities and saturation of the bed appeared faster at higher color intensities. The column had a 3-cm diameter and four different bed heights of 12.5, 25, 37.5 and 50 cm, which treated 5.25, 19.50, 35.25 and 51 L original textile wastewater, respectively, at the breakthrough time at a flow rate of 0.025 L min(-1). The theoretical service times evaluated from bed depth service time (BDST) approach for different column variables. The calculated and theoretical values of the exchange zone height were found with a difference of 27%. The various design parameters obtained from fixed-bed experimental studies showed good correlation with corresponding theoretical values, under different bed heights. The regeneration of the SMZ was also evaluated using a solution consisting of 30 g L(-1) NaCl and 1.5 g L(-1) NaOH at pH 12 and temperature 30 degrees C. Twice-regenerated SMZ showed the best performance compared with the others while first- and thrice-regenerated perform lower than the original SMZ.

  15. Comparative study of adsorptive removal of Cr(VI) ion from aqueous solution in fixed bed column by peanut shell and almond shell using empirical models and ANN.

    PubMed

    Banerjee, Munmun; Bar, Nirjhar; Basu, Ranjan Kumar; Das, Sudip Kumar

    2017-04-01

    Cr(VI) is a toxic water pollutant, which causes cancer and mutation in living organisms. Adsorption has become the most preferred method for removal of Cr(VI) due to its high efficiency and low cost. Peanut and almond shells were used as adsorbents in downflow fixed bed continuous column operation for Cr(VI) removal. The experiments were carried out to scrutinise the adsorptive capacity of the peanut shells and almond shells, as well as to find out the effect of various operating parameters such as column bed depth (5-10 cm), influent flow rate (10-22 ml min(-1)) and influent Cr(VI) concentration (10-20 mg L(-1)) on the Cr(VI) removal. The fixed bed column operation for Cr(VI) adsorption the equilibrium was illustrated by Langmuir isotherm. Different well-known mathematical models were applied to the experimental data to identify the best-fitted model to explain the bed dynamics. Prediction of the bed dynamics by Yan et al. model was found to be satisfactory. Applicability of artificial neural network (ANN) modelling is also reported. An ANN modelling of multilayer perceptron with gradient descent and Levenberg-Marquardt algorithms have also been tried to predict the percentage removal of Cr(VI). This study indicates that these adsorbents have an excellent potential and are useful for water treatment particularly small- and medium-sized industries of third world countries. Almond shell represents better adsorptive capacity as breakthrough time and exhaustion time are longer in comparison to peanut shell.

  16. A fuzzy-logic-based controller for methane production in anaerobic fixed-film reactors.

    PubMed

    Robles, A; Latrille, E; Ruano, M V; Steyer, J P

    2017-01-01

    The main objective of this work was to develop a controller for biogas production in continuous anaerobic fixed-bed reactors, which used effluent total volatile fatty acids (VFA) concentration as control input in order to prevent process acidification at closed loop. To this aim, a fuzzy-logic-based control system was developed, tuned and validated in an anaerobic fixed-bed reactor at pilot scale that treated industrial winery wastewater. The proposed controller varied the flow rate of wastewater entering the system as a function of the gaseous outflow rate of methane and VFA concentration. Simulation results show that the proposed controller is capable to achieve great process stability even when operating at high VFA concentrations. Pilot results showed the potential of this control approach to maintain the process working properly under similar conditions to the ones expected at full-scale plants.

  17. Massively parallel tag sequencing reveals the complexity of anaerobic marine protistan communities

    PubMed Central

    Stoeck, Thorsten; Behnke, Anke; Christen, Richard; Amaral-Zettler, Linda; Rodriguez-Mora, Maria J; Chistoserdov, Andrei; Orsi, William; Edgcomb, Virginia P

    2009-01-01

    Background Recent advances in sequencing strategies make possible unprecedented depth and scale of sampling for molecular detection of microbial diversity. Two major paradigm-shifting discoveries include the detection of bacterial diversity that is one to two orders of magnitude greater than previous estimates, and the discovery of an exciting 'rare biosphere' of molecular signatures ('species') of poorly understood ecological significance. We applied a high-throughput parallel tag sequencing (454 sequencing) protocol adopted for eukaryotes to investigate protistan community complexity in two contrasting anoxic marine ecosystems (Framvaren Fjord, Norway; Cariaco deep-sea basin, Venezuela). Both sampling sites have previously been scrutinized for protistan diversity by traditional clone library construction and Sanger sequencing. By comparing these clone library data with 454 amplicon library data, we assess the efficiency of high-throughput tag sequencing strategies. We here present a novel, highly conservative bioinformatic analysis pipeline for the processing of large tag sequence data sets. Results The analyses of ca. 250,000 sequence reads revealed that the number of detected Operational Taxonomic Units (OTUs) far exceeded previous richness estimates from the same sites based on clone libraries and Sanger sequencing. More than 90% of this diversity was represented by OTUs with less than 10 sequence tags. We detected a substantial number of taxonomic groups like Apusozoa, Chrysomerophytes, Centroheliozoa, Eustigmatophytes, hyphochytriomycetes, Ichthyosporea, Oikomonads, Phaeothamniophytes, and rhodophytes which remained undetected by previous clone library-based diversity surveys of the sampling sites. The most important innovations in our newly developed bioinformatics pipeline employ (i) BLASTN with query parameters adjusted for highly variable domains and a complete database of public ribosomal RNA (rRNA) gene sequences for taxonomic assignments of tags; (ii

  18. Dry anaerobic digestion of high solids content dairy manure at high organic loading rates in psychrophilic sequence batch reactor.

    PubMed

    Massé, Daniel I; Saady, Noori M Cata

    2015-05-01

    Cow manure with bedding is renewable organic biomass available around the year on dairy farms. Developing efficient and cost-effective psychrophilic dry anaerobic digestion (PDAD) processes could contribute to solving farm-related environmental, energy, and manure management problems in cold-climate regions. This study was to increase the organic loading rate (OLR), fed to a novel psychrophilic (20 °C) dry anaerobic digestion of 27% total solid dairy manure (cow feces and wheat straw) in sequence batch reactor (PDAD-SBR), by 133 to 160%. The PDAD-SBR process operated at treatment cycle length of 21 days and OLR of 7.0 and 8.0 g total chemical oxygen demand (TCOD) kg(-1) inoculum day(-1) (5.2 ± 0.1 and 5.8 ± 0.0 g volatile solids (VS) kg(-1) inoculum day(-1)) for four successive cycles (84 days) produced average specific methane yields (SMYs) of 147.1 ± 17.2 and 143.2 ± 11.7 normalized liters (NL) CH4 kg(-1) VS fed, respectively. PDAD of cow feces and wheat straw is possible with VS-based inoculum-to-substrate ratio of 1.45 at OLR of 8.0 g TCOD kg(-1) inoculum day(-1). Hydrolysis was the limiting step reaction. The VS removal averaged around 57.4 ± 0.5 and 60.5 ± 5.7% at OLR 7.0 and 8.0 g TCOD kg(-1) inoculum day(-1), respectively.

  19. Dynamics of a microbial community exposed to several concentrations of 2-chlorophenol in an anaerobic sequencing batch reactor.

    PubMed

    Beristain-Montiel, Lizeth; Martínez-Hernández, Sergio; de María Cuervo-López, Flor; Ramírez-Vives, Florina

    2015-01-01

    The aim of this study was to contribute to the knowledge on the dynamic of the microbial community involved in anaerobic degradation of different concentrations of 2-chlorophenol (2CP, from 28 to 196 mg 2CP-C/L) and a mixture of 2CP and phenol (from 28 to 196 mg phenol-C/L) and its relationship with the respiratory process in two anaerobic sequencing batch reactors (ASBR). The dynamic of the microbial community was evaluated by denaturant gradient gel electrophoresis (DGGE) and ecological indices (S and J indices). The respiratory process was evaluated by means of substrate consumption efficiency, biogas yield, and specific consumption rates as response variables. The high consumption efficiency (90%) and the constant biogas yields obtained at concentrations up to 140 mg C/L may be related with the evenness of microbial populations (J index=0.97±0.2) present in both reactors. Pseudomonas genus was present in all concentrations tested, suggesting a possible relationship with the dehalogenation observed in both reactors. The decrease in specific consumption rate and biogas yield as well as the accumulation of phenol and volatile fatty acids observed in both reactors at 196 mg 2CP-C/L might be associated with the disappearance of the bands related to Caulobacter and Bacillus. At these conditions, the disappearance of fermentative or acetogenic bacteria resulted in reduction of substrates required to carry out methanogenesis, which eventually might cause the declination in methanogenic populations present in the reactors.

  20. Production of bio-hydrogen by mesophilic anaerobic fermentation in an acid-phase sequencing batch reactor.

    PubMed

    Cheong, Dae-Yeol; Hansen, Conly L; Stevens, David K

    2007-02-15

    The pH and hydraulic retention time (HRT) of an anaerobic sequencing batch reactor (ASBR) were varied to optimize the conversion of carbohydrate-rich synthetic wastewater into bio-hydrogen. A full factorial design using evolutionary operation (EVOP) was used to determine the effect of the factors and to find the optimum condition of each factor required for high hydrogen production rate. Experimental results from 20 runs indicate that a maximum hydrogen production rate of 4,460-5,540 mL/L/day under the volumetric organic loading rate (VOLR) of 75 g-COD/L/day obtained at an observed design point of HRT = 8 h and pH = 5.7. The hydrogen production rate was strongly dependent on the HRT, and the effect was statistically significant (P < 0.05). However, no significant effect (P > 0.05) was found for the pH on the hydrogen production rate. When the ASBR conditions were set for a maximum hydrogen production rate, the hydrogen production yield and specific hydrogen production rate were 60-74 mL/g-COD and 330-360 mL/g-VSS/day, respectively. The hydrogen composition was 43-51%, and no methanogenesis was observed. Acetate, propionate, butyrate, valerate, caproate, and ethanol were major liquid intermediate metabolites during runs of this ASBR. The dominant fermentative types were butyrate-acetate or ethanol-acetate, representing the typical anaerobic pathway of Clostridium species. This hydrogen-producing ASBR had a higher hydrogen production rate, compared with that produced using continuous-flow stirred tank reactors (CSTRs). This study suggests that the hydrogen-producing ASBR is a promising bio-system for prolonged and stable hydrogen production.

  1. A comparison study on the high-rate co-digestion of sewage sludge and food waste using a temperature-phased anaerobic sequencing batch reactor system.

    PubMed

    Kim, Hyun-Woo; Nam, Joo-Youn; Shin, Hang-Sik

    2011-08-01

    Assessing contemporary anaerobic biotechnologies requires proofs on reliable performance in terms of renewable bioenergy recovery such as methane (CH(4)) production rate, CH(4) yield while removing volatile solid (VS) effectively. This study, therefore, aims to evaluate temperature-phased anaerobic sequencing batch reactor (TPASBR) system that is a promising approach for the sustainable treatment of organic fraction of municipal solid wastes (OFMSW). TPASBR system is compared with a conventional system, mesophilic two-stage anaerobic sequencing batch reactor system, which differs in operating temperature of 1st-stage. Results demonstrate that TPASBR system can obtain 44% VS removal from co-substrate of sewage sludge and food waste while producing 1.2m(3)CH(4)/m(3)(system)/d (0.2m(3)CH(4)/kgVS(added)) at organic loading rate of 6.1gVS/L/d through the synergy of sequencing-batch operation, co-digestion, and temperature-phasing. Consequently, the rapid and balanced anaerobic metabolism at thermophilic stage makes TPASBR system to afford high organic loading rate showing superior performance on OFMSW stabilization. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Treatment of anaerobic digester effluents of nylon wastewater through chemical precipitation and a sequencing batch reactor process.

    PubMed

    Huang, Haiming; Song, Qianwu; Wang, Wenjun; Wu, Shaowei; Dai, Jiankun

    2012-06-30

    Chemical precipitation, in combination with a sequencing batch reactor (SBR) process, was employed to remove pollutants from anaerobic digester effluents of nylon wastewater. The effects of the chemicals along with various Mg:N:P ratios on the chemical precipitation (struvite precipitation) were investigated. When brucite and H(3)PO(4) were applied at an Mg:N:P molar ratio of 3:1:1, an ammonia-removal rate of 81% was achieved, which was slightly more than that (80%) obtained with MgSO(4)·7H(2)O and Na(2)HPO(4)·12H(2)O at Mg:N:P molar ratios greater than the stoichiometric ratio. To further reduce the ammonia loads of the successive biotreatment, an overdose of phosphate with brucite and H(3)PO(4) was applied during chemical precipitation. The ammonia-removal rate at the Mg:N:P molar ratio of 3.5:1:1.05 reached 88%, with a residual PO(4)-P concentration of 16 mg/L. The economic analysis showed that the chemical cost of chemical precipitation could be reduced by about 41% when brucite and H(3)PO(4) were used instead of MgSO(4)·7H(2)O and Na(2)HPO(4)·12H(2)O. The subsequent biological process that used a sequencing batch reactor showed high removal rates of contaminants. The quality of the final effluent met the requisite effluent-discharging standards.

  3. In situ 13C DEPT-MRI as a tool to spatially resolve chemical conversion and selectivity of a heterogeneous catalytic reaction occurring in a fixed-bed reactor.

    PubMed

    Akpa, Belinda S; Mantle, Michael D; Sederman, Andrew J; Gladden, Lynn F

    2005-06-07

    The distortionless enhancement by polarisation transfer (DEPT) nuclear magnetic resonance (NMR) technique, combined with magnetic resonance imaging (MRI), has been used to provide the first in situ spatially-resolved and quantitative measurement of chemical conversion and selectivity within a fixed-bed reactor using natural abundance 13C NMR.

  4. Isolation and nucleotide sequence of the gene (aniA) encoding the major anaerobically induced outer membrane protein of Neisseria gonorrhoeae.

    PubMed Central

    Hoehn, G T; Clark, V L

    1992-01-01

    When grown under anaerobic conditions, Neisseria gonorrhoeae, the etiologic agent of the sexually transmitted disease gonorrhea, expresses several novel outer membrane proteins. One of these, Pan 1, has an apparent molecular mass of 54 kDa in electrophoresis and is recognized by serum samples from patients with gonococcal infection. The presence of antibodies to this protein in patient sera suggests that Pan 1 is expressed during gonococcal infection and, more importantly, that N. gonorrhoeae grows anaerobically in vivo. We have cloned the Pan 1 structural gene, aniA, by screening a gonococcal lambda gt11 expression library with monospecific, polyclonal anti-Pan 1 antiserum. Three distinct immunoreactive recombinants, containing overlapping fragments of DNA, were isolated and confirmed to be coding for Pan 1 protein sequences. Northern (RNA blot) hybridization of an insert from an aniA recombinant to total gonococcal cellular RNA revealed the presence of a 1.5-kb transcript that was specific to RNA from anaerobically grown gonococci, indicating that the aniA gene is regulated at the transcriptional level and is monocistronic. To characterize the aniA gene, we have sequenced the entire 2-kb region spanned by the overlapping recombinants. We have also performed primer extension analysis on RNA isolated from aerobically and anaerobically grown gonococci in order to define the aniA promoter region. Two putative primer extension products specific to organisms grown anaerobically were identified by homology to known Escherichia coli promoter sequences, suggesting that the regulation of aniA expression involves multiple promoter regions. Images PMID:1383156

  5. Complete genome sequence of the facultatively anaerobic, appendaged bacterium Muricauda ruestringensis type strain (B1T)

    SciTech Connect

    Huntemann, Marcel; Teshima, Hazuki; Lapidus, Alla L.; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, N; Mavromatis, K; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam L; Hauser, Loren John; Pan, Chongle; Brambilla, Evelyne-Marie; Rohde, Manfred; Spring, Stefan; Goker, Markus; Detter, J. Chris; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Woyke, Tanja

    2012-01-01

    Muricauda ruestringensis Bruns et al. 2001 is the type species of the genus Muricauda, which belongs to the family Flavobacteriaceae in the phylum Bacteroidetes. The species is of interest because of its isolated position in the genomically unexplored genus Muricauda, which is located in a part of the tree of life containing not many organisms with sequenced genomes. The genome, which consists of a circular chromosome of 3,842,422 bp length with a total of 3,478 protein-coding and 47 RNA genes, is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  6. Complete genome sequence of the facultatively anaerobic, appendaged bacterium Muricauda ruestringensis type strain (B1T)

    PubMed Central

    Huntemann, Marcel; Teshima, Hazuki; Lapidus, Alla; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, Natalia; Mavromatis, Konstantinos; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Pan, Chongle; Brambilla, Evelyne-Marie; Rohde, Manfred; Spring, Stefan; Göker, Markus; Detter, John C.; Bristow, James; Eisen, Jonathan A.; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C.; Klenk, Hans-Peter; Woyke, Tanja

    2012-01-01

    Muricauda ruestringensis Bruns et al. 2001 is the type species of the genus Muricauda, which belongs to the family Flavobacteriaceae in the phylum Bacteroidetes. The species is of interest because of its isolated position in the genomically unexplored genus Muricauda, which is located in a part of the tree of life containing not many organisms with sequenced genomes. The genome, which consists of a circular chromosome of 3,842,422 bp length with a total of 3,478 protein-coding and 47 RNA genes, is a part of the Genomic Encyclopedia of Bacteria and Archaea project. PMID:22768362

  7. Complete genome sequence of the facultatively anaerobic, appendaged bacterium Muricauda ruestringensis type strain (B1(T)).

    PubMed

    Huntemann, Marcel; Teshima, Hazuki; Lapidus, Alla; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Tapia, Roxanne; Goodwin, Lynne A; Pitluck, Sam; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, Natalia; Mavromatis, Konstantinos; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Pan, Chongle; Brambilla, Evelyne-Marie; Rohde, Manfred; Spring, Stefan; Göker, Markus; Detter, John C; Bristow, James; Eisen, Jonathan A; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Woyke, Tanja

    2012-05-25

    Muricauda ruestringensis Bruns et al. 2001 is the type species of the genus Muricauda, which belongs to the family Flavobacteriaceae in the phylum Bacteroidetes. The species is of interest because of its isolated position in the genomically unexplored genus Muricauda, which is located in a part of the tree of life containing not many organisms with sequenced genomes. The genome, which consists of a circular chromosome of 3,842,422 bp length with a total of 3,478 protein-coding and 47 RNA genes, is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  8. Fundamental aspects related to batch and fixed-bed sulfate sorption by the macroporous type 1 strong base ion exchange resin Purolite A500.

    PubMed

    Guimarães, Damaris; Leão, Versiane A

    2014-12-01

    Acid mine drainage is a natural process occurring when sulfide minerals such as pyrite are exposed to water and oxygen. The bacterially catalyzed oxidation of pyrite is particularly common in coal mining operations and usually results in a low-pH water polluted with toxic metals and sulfate. Although high sulfate concentrations can be reduced by gypsum precipitation, removing lower concentrations (below 1200 mg/L) remains a challenge. Therefore, this work sought to investigate the application of ion exchange resins for sulfate sorption. The macroporous type 1 strong base IX resin Purolite A500 was selected for bath and fixed-bed sorption experiments using synthetic sulfate solutions. Equilibrium experiments showed that sulfate loading on the resin can be described by the Langmuir isotherm with a maximum uptake of 59 mg mL-resin(-1). The enthalpy of sorption was determined as +2.83 kJ mol(-1), implying an endothermic physisorption process that occurred with decreasing entropy (-15.5 J mol(-1).K(-1)). Fixed-bed experiments were performed at different bed depths, flow rates, and initial sulfate concentrations. The Miura and Hashimoto model predicted a maximum bed loading of 25-30 g L-bed(-1) and indicated that both film diffusion (3.2 × 10(-3) cm s(-1) to 22.6 × 10(-3) cm s(-1)) and surface diffusion (1.46 × 10(-7) cm(2) s(-1) to 5.64 × 10(-7) cm(2) s(-1)) resistances control the sorption process. It was shown that IX resins are an alternative for the removal of sulfate from mine waters; they ensure very low residual concentrations, particularly in effluents where the sulfate concentration is below the gypsum solubility threshold. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Cloning and sequencing of the cellobiose 2-epimerase gene from an obligatory anaerobe, Ruminococcus albus.

    PubMed

    Ito, Shigeaki; Hamada, Shigeki; Yamaguchi, Kozo; Umene, Shingo; Ito, Hiroyuki; Matsui, Hirokazu; Ozawa, Tadahiro; Taguchi, Hidenori; Watanabe, Jun; Wasaki, Jun; Ito, Susumu

    2007-08-31

    Cellobiose 2-epimerase (EC 5.1.3.11) was first identified in 1967 as an extracellular enzyme that catalyzes the reversible epimerization between cellobiose and 4-O-beta-D-glucopyranosyl-D-mannose in a culture broth of Ruminococcus albus 7 (ATCC 27210(T)). Here, for the first time, we describe the purification of cellobiose 2-epimerase from R. albus NE1. The enzyme was found to 2-epimerize the reducing terminal glucose moieties of cellotriose and cellotetraose in addition to cellobiose. The gene encoding cellobiose 2-epimerase comprises 1170 bp (389 amino acids) and is present as a single copy in the genome. The deduced amino acid sequence of the mature enzyme contains the possible catalytic residues Arg52, His243, Glu246, and His374. Sequence analysis shows the gene shares a very low level of homology with N-acetyl-D-glucosamine 2-epimerases (EC 5.1.3.8), but no significant homology to any other epimerases reported to date.

  10. Microbial community changes during the start-up of an anaerobic/aerobic/anoxic-type sequencing batch reactor.

    PubMed

    Zhang, Qian; He, Jiajie; Wang, Hongyu; Ma, Fang; Yang, Kai; Wang, Jingbo

    2013-01-01

    An anaerobic/aerobic/anoxic-type sequencing batch reactor was started up during a summer rainy season to obtain enhanced biological phosphorus removal (EBPR), and its sludge microbial community was also monitored in the hope of observing the microbial community evolution of polyphosphate-accumulating organisms (PAOs). During the start-up process, a total of 17 bands of highest species richness were detected in the sludge microbial community, including Alpha-, Beta-, and Gamma- Proteobacteria, as well as Actinobacteria and Planctomycetes. Major microbial community structural change was observed in Rhodocyclus-related and Acinetobacter-related PAOs, glycogen-accumulating organisms (GAOs), and Actinobacteria. In contrast to the current belief that enrichment of PAOs is essential for the establishment of EBPR, PAOs were not favourably enriched in this study. Instead, Actinobacteria and GAOs overwhelmingly flourished. The overall conclusion of this study challenges the conventional view that EBPR cannot live without traditional PAOs. However, it suggests an non-negligible role of denitrifying phosphorus-accumulating bacteria in EBPR systems, as well as other uncultured bacteria.

  11. Influence of recirculation on the performance of anaerobic sequencing batch biofilm reactor (AnSBBR) treating hypersaline composite chemical wastewater.

    PubMed

    Mohan, S Venkata; Lalit Babu, V; Vijaya Bhaskar, Y; Sarma, P N

    2007-05-01

    Influence of recirculation on the performance of anaerobic sequencing batch biofilm reactor (AnSBBR) was studied in the process of treating hypersaline (total dissolved inorganic solids (TDIS) approximately 26 g/l) and low biodegradable (BOD/COD approximately 0.3) composite chemical wastewater. Significant enhancement in the substrate removal efficiency and biogas yield was observed after introducing the recirculation to the system. Maximum efficiency (COD removal efficiency - 51%; SDR - 3.14 kg COD/cum-day) was observed at recirculation to feed (R/F) ratio of 2 (OLR - 6.15 kg C OD/cum-day; HLR - 2.30 cum (liquid)/cum day; UFV(A) - 0.023 m/h). Subsequent increase of R/F to 3 (OLR - 6.15 kg COD/cum-day; HLR - 3.07cum (liquid)/cum-day; UFV(A) - 0.035 m/h) resulted in reduction in COD removal efficiency (32%; SDR - 1.97 kg COD/cum-day). The enhanced performance of the system due to the introduction of recirculation was attributed to the improvement in the mass transfer between the substrate present in the bulk liquid and the attached biofilm. The hydrodynamic behavior due to recirculation mode of operation reduced the concentration gradient (substrate inhibition) of substrate and reaction by-products (VFA) resulting in mixed flow conditions.

  12. Methane production from the soluble fraction of distillers' dried grains with solubles in anaerobic sequencing batch reactors.

    PubMed

    Cassidy, D P; Hirl, P J; Belia, E

    2008-06-01

    Methane production from the soluble fraction of distillers' dried grains with solubles, a co-product of ethanol production, was studied in 2-L anaerobic sequencing batch reactors (ASBRs) under 10 different operating conditions. Methane production and chemical oxygen demand (COD) removal were quantified for a wide range of operating parameters. Chemical oxygen demand removals of 64 to 95% were achieved at organic loading rates ranging from 1.5 to 22.2 g COD/L x d, solids retention times from 8 to 40 days, and food-to-microorganism ratios ranging from 0.4 to 1.9 g COD/g volatile suspended solids (VSS) x d. Biogas methane content varied from 61 to 74%, with 0.29 L CH4 produced/g COD removed. Roughly 56% of the influent COD and 84% of the COD removed in the ASBRs was converted to methane. Microbial yield (Y) and decay (b) constants were determined to be Y = 0.126 g VSS/g COD removed and b = 0.032 day(-1), respectively. Methane produced from co-products can reduce the costs and fossil-fuel consumption of ethanol manufacture.

  13. The complete genome sequence of Chlorobium tepidum TLS, a photosynthetic, anaerobic, green-sulfur bacterium

    PubMed Central

    Eisen, Jonathan A.; Nelson, Karen E.; Paulsen, Ian T.; Heidelberg, John F.; Wu, Martin; Dodson, Robert J.; Deboy, Robert; Gwinn, Michelle L.; Nelson, William C.; Haft, Daniel H.; Hickey, Erin K.; Peterson, Jeremy D.; Durkin, A. Scott; Kolonay, James L.; Yang, Fan; Holt, Ingeborg; Umayam, Lowell A.; Mason, Tanya; Brenner, Michael; Shea, Terrance P.; Parksey, Debbie; Nierman, William C.; Feldblyum, Tamara V.; Hansen, Cheryl L.; Craven, M. Brook; Radune, Diana; Vamathevan, Jessica; Khouri, Hoda; White, Owen; Gruber, Tanja M.; Ketchum, Karen A.; Venter, J. Craig; Tettelin, Hervé; Bryant, Donald A.; Fraser, Claire M.

    2002-01-01

    The complete genome of the green-sulfur eubacterium Chlorobium tepidum TLS was determined to be a single circular chromosome of 2,154,946 bp. This represents the first genome sequence from the phylum Chlorobia, whose members perform anoxygenic photosynthesis by the reductive tricarboxylic acid cycle. Genome comparisons have identified genes in C. tepidum that are highly conserved among photosynthetic species. Many of these have no assigned function and may play novel roles in photosynthesis or photobiology. Phylogenomic analysis reveals likely duplications of genes involved in biosynthetic pathways for photosynthesis and the metabolism of sulfur and nitrogen as well as strong similarities between metabolic processes in C. tepidum and many Archaeal species. PMID:12093901

  14. ANAMMOX-like performances for nitrogen removal from ammonium-sulfate-rich wastewater in an anaerobic sequencing batch reactor.

    PubMed

    Prachakittikul, Pensiri; Wantawin, Chalermraj; Noophan, Pongsak Lek; Boonapatcharoen, Nimaradee

    2016-01-01

    Ammonium removal by the ANaerobic AMonium OXidation (ANAMMOX) process was observed through the Sulfate-Reducing Ammonium Oxidation (SRAO) process. The same concentration of ammonium (100 mg N L(-1)) was applied to two anaerobic sequencing batch reactors (AnSBRs) that were inoculated with the same activated sludge from the Vermicelli wastewater treatment process, while nitrite was fed in ANAMMOX and sulfate in SRAO reactors. In SRAO-AnSBR, in substrates that were fed with a ratio of NH4(+)/SO4(2-) at 1:0.4 ± 0.03, a hydraulic retention time (HRT) of 48 h and without sludge draining, the Ammonium Removal Rate (ARR) was 0.02 ± 0.01 kg N m(-3).d(-1). Adding specific ANAMMOX substrates to SRAO-AnSBR sludge in batch tests results in specific ammonium and nitrite removal rates of 0.198 and 0.139 g N g(-1) VSS.d, respectively, indicating that the ANAMMOX activity contributes to the removal of ammonium in the SRAO process using the nitrite that is produced from SRAO. Nevertheless, the inability of ANAMMOX to utilize sulfate to oxidize ammonium was also investigated in batch tests by augmenting enriched ANAMMOX culture in SRAO-AnSBR sludge and without nitrite supply. The time course of sulfate in a 24-hour cycle of SRAO-AnSBR showed an increase in sulfate after 6 h. For enriched SRAO culture, the uptake molar ratio of NH4(+)/SO4(2-) at 8 hours in a batch test was 1:0.82 lower than the value of 1:0.20 ± 0.09 as obtained in an SRAO-AnSBR effluent, while the stoichiometric ratio of 1:0.5 that includes the ANAMMOX reaction was in this range. After a longer operation of more than 2 years without sludge draining, the accumulation of sulfate and the reduction of ammonium removal were observed, probably due to the gradual increase in the sulfur denitrification rate and the competitive use of nitrite with ANAMMOX. The 16S rRNA gene PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and PCR cloning analyses resulted in the detection of the ANAMMOX

  15. Demand-driven biogas production from sugar beet silage in a novel fixed bed disc reactor under mesophilic and thermophilic conditions.

    PubMed

    Terboven, Christiane; Ramm, Patrice; Herrmann, Christiane

    2017-10-01

    A newly developed fixed bed disc reactor (FBDR) which combines biofilm formation on biofilm carriers and reactor agitation in one single system was assessed for its applicability to demand-driven biogas production by variable feeding of sugar beet silage. Five different feeding patterns were studied at an organic loading of 4gVSL(-1)d(-1) under mesophilic and thermophilic conditions. High methane yields of 449-462LNkgVS were reached. Feeding variable punctual loadings caused immediate response with 1.2- to 3.5-fold increase in biogas production rates within 15min. Although variable feeding did not induce process instability, a temporary decrease in pH-value and methane concentration below 40% occurred. Thermophilic temperature was advantageous as it resulted in a more rapid, higher methane production and less pronounced decrease in methane content after feeding. The FBDR was demonstrated to be well-suited for flexible biogas production, but further research and comparison with traditional reactor systems are required. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Structural characterisation of pretreated solids from flow-through liquid hot water treatment of sugarcane bagasse in a fixed-bed reactor.

    PubMed

    Reddy, Prashant; Lekha, Prabashni; Reynolds, Wienke; Kirsch, Christian

    2015-05-01

    Untreated sugarcane bagasse and sugarcane bagasse pretreated with flow-through liquid hot water (LHW) treatment (170-207°C and 204-250 ml/min) in a fixed-bed reactor have been structurally characterised. Field emission gun scanning electron microscopy (FEG-SEM) and transmission electron microscopy (TEM) were used to investigate changes in the residues, in particular due to the fate of lignin. FEG-SEM results show that the LHW treatment modified the surface morphology of the pretreated bagasse with lignin droplets being observed on the fibre surface. TEM showed an increase in the plant cell wall porosity and lignin migration across the plant cell wall. Increases in pretreatment temperature were observed to increase the average size and density of lignin droplets on the fibre surface. The results provide evidence that for LHW flow-through treatment, just as for batch treatment, lignin repolymerisation and deposition on the surface of pretreated sugarcane bagasse is an important consideration.

  17. Pressurized pyrolysis of rice husk in an inert gas sweeping fixed-bed reactor with a focus on bio-oil deoxygenation.

    PubMed

    Qian, Yangyang; Zhang, Jie; Wang, Jie

    2014-12-01

    The pyrolysis of rice husk was conducted in a fixed-bed reactor with a sweeping nitrogen gas to investigate the effects of pressure on the pyrolytic behaviors. The release rates of main gases during the pyrolysis, the distributions of four products (char, bio-oil, water and gas), the elemental compositions of char, bio-oil and gas, and the typical compounds in bio-oil were determined. It was found that the elevation of pressure from 0.1MPa to 5.0MPa facilitated the dehydration and decarboxylation of bio-oil, and the bio-oils obtained under the elevated pressures had significantly less oxygen and higher calorific value than those obtained under atmospheric pressure. The former bio-oils embraced more acetic acid, phenols and guaiacols. The elevation of pressure increased the formation of CH4 partially via the gas-phase reactions. An attempt is made in this study to clarify "the pure pressure effect" and "the combined effect with residence time". Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Enhanced adsorption of cesium on PVA-alginate encapsulated Prussian blue-graphene oxide hydrogel beads in a fixed-bed column system.

    PubMed

    Jang, Jiseon; Lee, Dae Sung

    2016-10-01

    A continuous fixed-bed column study was performed using PVA-alginate encapsulated Prussian blue-graphene oxide (PB-GO) hydrogel beads as a novel adsorbent for the removal of cesium from aqueous solutions. The effects of different operating parameters, such as initial cesium concentration, pH, bed height, flow rate, and bead size, were investigated. The maximum adsorption capacity of the PB-GO hydrogel beads was 164.5mg/g at an initial cesium concentration of 5mM, bed height of 20cm, and flow rate of 0.83mL/min at pH 7. The Thomas, Adams-Bohart, and Yoon-Nelson models were applied to the experimental data to predict the breakthrough curves using non-linear regression. Although both the Thomas and Yoon-Nelson models showed good agreement with the experimental data, the Yoon-Nelson model was found to provide the best representation for cesium adsorption on the adsorbent, based on the χ(2) analysis.

  19. Pyrolysis of waste animal fats in a fixed-bed reactor: production and characterization of bio-oil and bio-char.

    PubMed

    Ben Hassen-Trabelsi, A; Kraiem, T; Naoui, S; Belayouni, H

    2014-01-01

    Several animal (lamb, poultry and swine) fatty wastes were pyrolyzed under nitrogen, in a laboratory scale fixed-bed reactor and the main products (liquid bio-oil, solid bio-char and syngas) were obtained. The purpose of this study is to produce and characterize bio-oil and bio-char obtained from pyrolysis of animal fatty wastes. The maximum production of bio-oil was achieved at a pyrolysis temperature of 500 °C and a heating rate of 5 °C/min. The chemical (GC-MS analyses) and spectroscopic analyses (FTIR analyses) of bio-oil showed that it is a complex mixture consisting of different classes of organic compounds, i.e., hydrocarbons (alkanes, alkenes, cyclic compounds...etc.), carboxylic acids, aldehydes, ketones, esters,...etc. According to fuel properties, produced bio-oils showed good properties, suitable for its use as an engine fuel or as a potential source for synthetic fuels and chemical feedstock. Obtained bio-chars had low carbon content and high ash content which make them unattractive for as renewable source energy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Biosorption and desorption of lanthanum(III) and neodymium(III) in fixed-bed columns with Sargassum sp.: perspectives for separation of rare earth metals.

    PubMed

    Oliveira, Robson C; Guibal, Eric; Garcia, Oswaldo

    2012-01-01

    Rare earth (RE) metals are essentials for the manufacturing of high-technology products. The separation of RE is complex and expensive; biosorption is an alternative to conventional processes. This work focuses on the biosorption of monocomponent and bicomponent solutions of lanthanum(III) and neodymium(III) in fixed-bed columns using Sargassum sp. biomass. The desorption of metals with HCl 0.10 mol L(-1) from loaded biomass is also carried out with the objective of increasing the efficiency of metal separation. Simple models have been successfully used to model breakthrough curves (i.e., Thomas, Bohart-Adams, and Yoon-Nelson equations) for the biosorption of monocomponent solutions. From biosorption and desorption experiments in both monocomponent and bicomponent solutions, a slight selectivity of the biomass for Nd(III) over La(III) is observed. The experiments did not find an effective separation of the RE studied, but their results indicate a possible partition between the metals, which is the fundamental condition for separation perspectives.

  1. Thermolysis of microalgae and duckweed in a CO₂-swept fixed-bed reactor: bio-oil yield and compositional effects.

    PubMed

    Campanella, Alejandrina; Muncrief, Rachel; Harold, Michael P; Griffith, David C; Whitton, Norman M; Weber, Robert S

    2012-04-01

    Microalgae and duckweed were grown and harvested over a three-month period in CO(2)-sparged helioreactors and open earthen ponds, respectively. The biomass feedstocks were thermolyzed in a thermogravimetric analyzer (TGA) and fixed-bed reactor to produce a fuel precursor coined "bioleum". Analysis of the thermolysis kinetics revealed an increase in the activation energy with heating rate for both aquatic species. Activation energies were lower than literature-reported values for lignocellulosics, corroborated by TGA thermolysis of pinewood. Thermolysis of microalgae resulted in higher bioleum and energy yields than for duckweed, reflecting differences in the biomass composition. The algal bioleum properties resemble those of crude petroleum except for higher nitrogen and oxygen content and acid number. Speciation identified 300+ compounds in the oil phase, with similar amounts of hydrocarbons and oxygenates, while acetic acid was the major species in the aqueous phase. The compounds were classified according to their degree of aromaticity, oxygenation, and nitrogenation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Adsorption in a Fixed-Bed Column and Stability of the Antibiotic Oxytetracycline Supported on Zn(II)-[2-Methylimidazolate] Frameworks in Aqueous Media

    PubMed Central

    Anceski Bataglion, Giovana; Nogueira Eberlin, Marcos; Machado Ronconi, Célia

    2015-01-01

    A metal-organic framework, Zn-[2-methylimidazolate] frameworks (ZIF-8), was used as adsorbent material to remove different concentrations of oxytetracycline (OTC) antibiotic in a fixed-bed column. The OTC was studied at concentrations of 10, 25 and 40 mg L-1. At 40 mg L-1, the breakthrough point was reached after approximately 10 minutes, while at 10 and 25 mg L-1 this point was reached in about 30 minutes. The highest removal rate of 60% for the 10 mg L-1 concentration was reached after 200 minutes. The highest adsorption capacity (28.3 mg g-1) was attained for 25 mg L-1 of OTC. After the adsorption process, a band shift was observed in the UV-Vis spectrum of the eluate. Additional studies were carried out to determine the cause of this band shift, involving a mass spectrometry (MS) analysis of the supernatant liquid during the process. This investigation revealed that the main route of adsorption consisted of the coordination of OTC with the metallic zinc centers of ZIF-8. The materials were characterized by thermal analysis (TA), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and infrared spectroscopy (IR) before and after adsorption, confirming the presence of OTC in the ZIF-8 and the latter’s structural stability after the adsorption process. PMID:26057121

  3. Adsorption in a Fixed-Bed Column and Stability of the Antibiotic Oxytetracycline Supported on Zn(II)-[2-Methylimidazolate] Frameworks in Aqueous Media.

    PubMed

    dos Santos Ferreira da Silva, Janine; López Malo, Daniel; Anceski Bataglion, Giovana; Nogueira Eberlin, Marcos; Machado Ronconi, Célia; Alves Júnior, Severino; de Sá, Gilberto Fernandes

    2015-01-01

    A metal-organic framework, Zn-[2-methylimidazolate] frameworks (ZIF-8), was used as adsorbent material to remove different concentrations of oxytetracycline (OTC) antibiotic in a fixed-bed column. The OTC was studied at concentrations of 10, 25 and 40 mg L(-1). At 40 mg L(-1), the breakthrough point was reached after approximately 10 minutes, while at 10 and 25 mg L(-1) this point was reached in about 30 minutes. The highest removal rate of 60% for the 10 mg L(-1) concentration was reached after 200 minutes. The highest adsorption capacity (28.3 mg g(-1)) was attained for 25 mg L(-1) of OTC. After the adsorption process, a band shift was observed in the UV-Vis spectrum of the eluate. Additional studies were carried out to determine the cause of this band shift, involving a mass spectrometry (MS) analysis of the supernatant liquid during the process. This investigation revealed that the main route of adsorption consisted of the coordination of OTC with the metallic zinc centers of ZIF-8. The materials were characterized by thermal analysis (TA), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and infrared spectroscopy (IR) before and after adsorption, confirming the presence of OTC in the ZIF-8 and the latter's structural stability after the adsorption process.

  4. Evaluation and modification of ASPEN fixed-bed gasifier models for inclusion in an integrated gasification combined-cycle power plant simulation

    SciTech Connect

    Stefano, J.M.

    1985-05-01

    Several Advanced System for Process Engineering (ASPEN) fixed-bed gasifier models have been evaluated to determine which is the most suitable model for use in an integrated gasification combined-cycle (IGCC) power plant simulation. Four existing ASPEN models were considered: RGAS, a dry ash gasifier model developed by Halcon/Scientific Design Company; USRWEN, the WEN II dry ash gasifier model originally developed by C.Y. Wen at West Virginia University; the slagging gasifier model developed by Massachusetts Institute of Technology (MIT) and based on Continental Oil Company's (CONOCO) design study for the proposed Pipeline Demonstration Plant; and the ORNL dry ash gasifier model developed by Oak Ridge National Laboratory for the simulation of the Tri-States Indirect Liquefaction Process. Because none of the models studied were suitable in their present form for inclusion in an IGCC power plant simulation, the SLAGGER model was developed by making significant modifications to the MIT model. The major problems with the existing ASPEN models were most often inaccurate material and energy balances, limitations of coal type, or long run times. The SLAGGER model includes simplifications and improvements over the MIT model, runs quickly (less than 30 seconds of computer time on a VAX-11/780), and gives more accurate mass and energy balances.

  5. Pyrolysis of waste animal fats in a fixed-bed reactor: Production and characterization of bio-oil and bio-char

    SciTech Connect

    Ben Hassen-Trabelsi, A.; Kraiem, T.; Naoui, S.; Belayouni, H.

    2014-01-15

    Highlights: • Produced bio-fuels (bio-oil and bio-char) from some animal fatty wastes. • Investigated the effects of main parameters on pyrolysis products distribution. • Determined the suitable conditions for the production of the maximum of bio-oil. • Characterized bio-oils and bio-chars obtained from several animal fatty wastes. - Abstract: Several animal (lamb, poultry and swine) fatty wastes were pyrolyzed under nitrogen, in a laboratory scale fixed-bed reactor and the main products (liquid bio-oil, solid bio-char and syngas) were obtained. The purpose of this study is to produce and characterize bio-oil and bio-char obtained from pyrolysis of animal fatty wastes. The maximum production of bio-oil was achieved at a pyrolysis temperature of 500 °C and a heating rate of 5 °C/min. The chemical (GC–MS analyses) and spectroscopic analyses (FTIR analyses) of bio-oil showed that it is a complex mixture consisting of different classes of organic compounds, i.e., hydrocarbons (alkanes, alkenes, cyclic compounds…etc.), carboxylic acids, aldehydes, ketones, esters,…etc. According to fuel properties, produced bio-oils showed good properties, suitable for its use as an engine fuel or as a potential source for synthetic fuels and chemical feedstock. Obtained bio-chars had low carbon content and high ash content which make them unattractive for as renewable source energy.

  6. Bimodal porous silica microspheres decorated with polydopamine nano-particles for the adsorption of methylene blue in fixed-bed columns.

    PubMed

    Ataei-Germi, Taher; Nematollahzadeh, Ali

    2016-05-15

    Bimodal meso/macro-porous silica microspheres (MSM) were synthesized by a modified sol-emulsion-gel method and then the surface was coated with polydopamine (PDA) nano-particles of 39nm in size. Focusing on the encouraging properties of the synthesized adsorbent, such as high specific surface area (612.3m(2)g(-1), because of mesopores), fast mass transfer (0.9-2.67×10(-3)mLmin(-1)mg, because of macropores), and abundant "adhesive" functional groups of PDA, it was used for the removal of methylene blue (MB) from aqueous solution in a fixed-bed column. The effect of different parameters such as pH, initial concentration, and flow rate was studied. The results revealed that an appropriate sorption condition is an alkaline solution of MB (e.g., pH 10) at low flow rate (less than 5mLmin(-1)). Furthermore, the compatibility of the experimental data with mathematical models such as Thomas and Adams-Bohart was investigated. Both of the models showed a good agreement with the experimental data (R(2)=0.9954-0.9994), and could be applied for the prediction of the column properties and breakthrough curves. Regeneration of the column was performed by using HCl solution with a concentration of 0.1M as an eluent. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Selective hydrogenolysis of raw glycerol to 1,2-propanediol over Cu-ZnO catalysts in fixed-bed reactor.

    PubMed

    Gao, Qiang; Xu, Bolian; Tong, Qing; Fan, Yining

    2016-01-01

    The catalytic properties of Cu-ZnO catalysts for glycerol hydrogenolysis to 1,2-propanediol (1,2-PDO) were tested in a fixed-bed reactor at 250 °C and 2.0 MPa H2. The relation between composition, surface properties, and catalytic performance of glycerol hydrogenation of Cu-ZnO catalysts was studied using nitrogen adsorption (BET methods), XRD, H2 temperature-programmed reduction, and N2O chemisorptions. It was found that there was a close link between the surface CuO amount of Cu-ZnO catalyst and the reactivity for glycerol hydrogenation. The Cu-ZnO catalyst (Cu/Zn = 1.86) which had the highest surface Cu amount showed the best catalytic activity for glycerol hydrogenolysis. Furthermore, Cu-ZnO catalyst presented good stability and remarkable catalytic activity for glycerol hydrogenolysis to 1,2-PDO using raw glycerol derived from the fat saponification as feedstock.

  8. Simulating the performance of fixed-bed granular activated carbon adsorbers: removal of synthetic organic chemicals in the presence of background organic matter.

    PubMed

    Jarvie, Michelle Edith; Hand, David W; Bhuvendralingam, Shanmugalingam; Crittenden, John C; Hokanson, Dave R

    2005-06-01

    Granular activated carbon (GAC) adsorption is an effective treatment technology for the removal of synthetic organic chemicals (SOCs) from drinking water supplies. This treatment process can be expensive if not properly designed. Application of mathematical models is an attractive method to evaluate the impact of process variables on process design and performance. Practical guidelines were developed to select an appropriate model framework and to estimate site-specific model parameters to predict GAC adsorber performance. Pilot plant and field-scale data from 11 different studies were utilized to investigate the effectiveness of this approach in predicting adsorber performance in the presence of background organic batter (BOM). These data represent surface and ground water sources from four different countries. The modeling approach was able to adequately describe fixed-bed adsorber performance for the purpose of determining the carbon usage rate and process design variables. This approach is more accurate at predicting bed life in the presence of BOM than the current methods commonly used by practicing engineers.

  9. Characteristics and potential values of bio-oil, syngas and biochar derived from Salsola collina Pall. in a fixed bed slow pyrolysis system.

    PubMed

    Yue, Yan; Lin, Qimei; Irfan, Muhammad; Chen, Qun; Zhao, Xiaorong

    2016-11-01

    Salsola collina Pall. as a typical euhalophyte was slowly pyrolyzed at 300°C, 500°C and 700°C in a fixed-bed system. The physiochemical properties of syngas, bio-oil and biochar were assayed to understand the impact of pyrolysis temperature on these parameters and then to evaluate their potential values. The results showed that syngas yield (26.07-46.37%) increased with pyrolysis temperature, while biochar yield (47.54-26.83%) decreased. Bio-oil yield (26-30%) was hardly affected by pyrolysis temperature. Both syngas and bio-oil had poor values as direct fuel. The euhalophyte-derived biochar had higher aromaticity (H/C 0.16-0.85, O/C 0.06-0.26), higher cation exchange capacity (198.82-435.74cmolkg(-1)), and higher K(+) (59.35-80.42gkg(-1)) and Na(+) (37.56-53.26gkg(-1)) compared with glycophyte-derived biochars. Our findings imply that halophyte biochar may be more suitable to use as a soil conditioner, which is worthy of further study.

  10. The contrast study of anammox-denitrifying system in two non-woven fixed-bed bioreactors (NFBR) treating different low C/N ratio sewage.

    PubMed

    Gao, Fan; Zhang, Hanmin; Yang, Fenglin; Qiang, Hong; Zhang, Guangyi

    2012-06-01

    Two non-woven fixed-bed bioreactors (NFBR) based on different substrates (nitrite and nitrate) were constructed to study the environmental adaptability for temperature and organic matter of anammox-denitrifying system and nitrogen removal performance. The two reactors were successfully operated for 200 days. The average removal rates of nitrogen and COD of R2 were 81% and 93%, respectively. Besides, the nitrogen removal rate of R1 was 95% under not more than 105 mg/l of COD. The experimental results indicated that the R2 based on nitrate had a good nitrogen removal performance at room temperature (25 °C). Additionally, the analysis results of fluorescence in situ hybridization (FISH) showed that the percentage compositions of anammox in R1 and R2 were 84% and 65% on day 189. Finally, the possible nitrogen removal model of anammox-denitrifying system was constructed. According to nitrogen balance and C/N ratios of denitrification, the nitrogen removal approaches of R1 and R2 were obtained.

  11. Pyrolysis of oil palm mesocarp fiber and palm frond in a slow-heating fixed-bed reactor: A comparative study.

    PubMed

    Kabir, G; Mohd Din, A T; Hameed, B H

    2017-10-01

    Oil palm mesocarp fiber (OPMF) and palm frond (PF) were respectively devolatilized by pyrolysis to OPMF-oil and PF-oil bio-oils and biochars, OPMF-char and PF-char in a slow-heating fixed-bed reactor. In particular, the OPMF-oil and PF-oil were produced to a maximum yield of 48wt% and 47wt% bio-oils at 550°C and 600°C, respectively. The high heating values (HHVs) of OPMF-oil and PF-oil were respectively found to be 23MJ/kg and 21MJ/kg, whereas 24.84MJ/kg and 24.15MJ/kg were for the corresponding biochar. The HHVs of the bio-oils and biochars are associated with low O/C ratios to be higher than those of the corresponding biomass. The Fourier transform infrared spectra and peak area ratios highlighted the effect of pyrolysis temperatures on the bio-oil compositions. The bio-oils are pervaded with numerous oxygenated carbonyl and aromatic compounds as suitable feedstocks for renewable fuels and chemicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Study of kinetic and fixed bed operation of removal of sulfate anions from an industrial wastewater by an anion exchange resin.

    PubMed

    Haghsheno, Reza; Mohebbi, Ali; Hashemipour, Hassan; Sarrafi, Amir

    2009-07-30

    Sulfate anions represent very important wastewater pollutants, which appear in the effluents discharged from copper mines. In this study, for the first time, an attempt has been made on the removal of sulfate anions by an ion exchange resin. This work is focused on the removal of sulfate anions from the Sarcheshmeh copper complex (Kerman province, Southeast of Iran) wastewater by an anion exchange resin. Batch experiments of sulfate anions adsorption on Lewatit K6362 resin were carried out to determine the adsorption equilibrium data and the relation of adsorption isotherms. Isothermal data can be fitted with Freundlich adsorption isotherms better than Langmuir equation. The results show that maximum removal of sulfate anions take places in the resin dosage of 1000 mg/100ml and the adsorption of sulfate anions on the resin follows reversible first-order kinetics. The overall adsorption rate constants were compared for different initial concentrations. Finally, the effects of parameters such as the flow rate, bed height and inlet adsorbate concentration on the breakthrough curve in a fixed bed column were studied in detail.

  13. Adsorption of Hg(II) and Pb(II) ions by nanoscale zero valent iron supported on ostrich bone ash in a fixed-bed column system.

    PubMed

    Amiri, Mohammad Javad; Abedi-Koupai, Jahangir; Eslamian, Saeid

    2017-07-01

    In this research, ostrich bone ash (OBA) was modified with nanoscale zerovalent iron (nZVI) particles and applied as a novel composite adsorbent (OBA/nZVI) for dynamic adsorption/reduction of Hg(II) and Pb(II) ions in a fixed-bed column system. Entrapment of nZVI in OBA beads barricades the particles from oxidation and aggregation. The dynamic behavior of metal ions removal by OBA/nZVI was assessed as a function of inlet flow rates, bed height, initial pollutants concentration and pH. The synthesized OBA/nZVI composite was characterized by several physicochemical techniques. Increase in pH and bed height and decrease in flow rates and initial metal concentration resulted in delay of breakthrough time. OBA breakthrough profile is sharper than the OBA/nZVI breakthrough curve for both metal ions and the breakthrough times increase in the order OBA/nZVI-Hg(II) > OBA/nZVI-Pb(II) > OBA-Pb(II) > OBA-Hg(II). Based on the experiment results, redox reaction is expected to occur to a certain extent, as the standard reduction potentials of Hg(II) and Pb(II) are more than that of Fe(II). From a practical point of view, the OBA/nZVI could be applied as a material to remove Hg(II) and Pb(II) ions from natural surface and ground water with a pH value of 5-9.

  14. Fast pyrolysis of durian (Durio zibethinus L) shell in a drop-type fixed bed reactor: Pyrolysis behavior and product analyses.

    PubMed

    Tan, Y L; Abdullah, A Z; Hameed, B H

    2017-06-23

    Durian shell (DS) was pyrolyzed in a drop-type fixed-bed reactor to study the physicochemical properties of the products. The experiment was carried out with different particle sizes (up to 5mm) and reaction temperatures (250-650°C). The highest bio-oil yield was obtained at 650°C (57.45wt%) with DS size of 1-2mm. The elemental composition and higher heating value of the feedstock, bio-oil (650°C), and bio-char (650°C) were determined and compared. The compositions of product gases were determined via gas chromatography with thermal conductivity detector. The chemical composition of bio-oil was analyzed by gas chromatography-mass spectrometry. The bio-oil produced at lower temperature yields more alcohols, whereas the bio-oil produced at higher temperature contains more aromatics and carbonyls. Bio-oil has potential to be used as liquid fuel or fine chemical precursor after further upgrading. The results further showed the potential of bio-char as a solid fuel. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. In situ magnetic resonance measurement of conversion, hydrodynamics and mass transfer during single- and two-phase flow in fixed-bed reactors.

    PubMed

    Gladden, L F; Alexander, P; Britton, M M; Mantle, M D; Sederman, A J; Yuen, E H L

    2003-01-01

    In recent years there has been increasing interest in applying magnetic resonance (MR) techniques in areas of engineering and chemical technology. The science that underpins many of these applications is the physics and chemistry of transport and reaction processes in porous materials. Key to the exploitation of MR methods will be our ability to demonstrate that MR yields information that cannot be obtained using conventional measurement techniques in engineering research. This article describes two case studies that highlight the power of MR to give new insights to chemical engineers. First, we demonstrate the application of MR techniques to explore both mass transfer and chemical conversion in situ within a fixed bed of catalyst, and we then use these data to identify the rate-controlling step of the chemical conversion. Second, we implement a rapid imaging technique to study the stability of the gas-liquid distribution in the low- and high-interaction two-phase flow regimes in a trickle-bed reactor.

  16. Removal of Pb(II) ions from aqueous solution using water hyacinth root by fixed-bed column and ANN modeling.

    PubMed

    Mitra, Tania; Singha, Biswajit; Bar, Nirjhar; Das, Sudip Kumar

    2014-05-30

    Hyacinth root was used as a biosorbent for generating adsorption data in fixed-bed glass column. The influence of different operating parameters like inlet Pb(II) ion concentration, liquid flow rate and bed height on the breakthrough curves and the performance of the column was studied. The result showed that the adsorption efficiency increased with increase in bed height and decreased with increase in inlet Pb(II) ion concentration and flow rate. Increasing the flow rate resulted in shorter time for bed saturation. The result showed that as the bed height increased the availability of more number of adsorption sites in the bed increased, hence the throughput volume of the aqueous solution also increased. The adsorption kinetics was analyzed using different models. It was observed that maximum adsorption capacity increased with increase in flow rate and initial Pb(II) ion concentration but decreased with increase in bed height. Applicability of artificial neural network (ANN) modeling for the prediction of Pb(II) ion removal was also reported by using multilayer perceptron with backpropagation, Levenberg-Marquardt and scaled conjugate algorithms and four different transfer functions in a hidden layer and a linear output transfer function. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Synthesis and characterization of organic-inorganic core-shell structure nanocomposite and application for Zn ions removal from aqueous solution in a fixed-bed column

    NASA Astrophysics Data System (ADS)

    Ghasemi, Shokoofeh; Ghorbani, Mohsen; Ghazi, Mohsen Mehdipour

    2015-12-01

    An organic-inorganic core/shell structure, γ-Fe2O3/polyrhodanine nanocomposite with γ-Fe2O3 nanoparticle as core with average diameter of 15 nm and polyrhodanine as shell with thickness of 1.5 nm, has been synthesized via chemical oxidation polymerization and applied for adsorption of Zn ions from aqueous solution in a fixed-bed column. The properties of nanocomposite were characterized with transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM). The performance of the column was assessed under variable bed heights (10, 15 and 20 cm) and influent Zn concentrations (50, 100 and 150 ppm) at a constant flow rate (0.5 mL/min). The results demonstrated that the breakthrough curves are S-shaped and the breakthrough time increases with increasing bed height and decreases with increasing influent concentration. Moreover, the dynamics of the adsorption process were evaluated by using Adams-Bohart, bed depth service time (BDST), Thomas and Yoon-Nelson kinetic models. The models were nearly in good agreement with the experimental data.

  18. Effects of temperature, pressure, and carrier gas on the cracking of coal tar over a char-dolomite mixtures and calcined dolomite in a fixed-bed reactor

    SciTech Connect

    Seshadri, K.; Shamsi, A.

    1998-10-01

    A distillation fraction of a coal-derived liquid (tar) was cracked over a char-dolomite mixture, calcined dolomite, and silicon carbide in a fixed-bed reactor. The char-dolomite mixture (FWC) was produced from Pittsburgh No. 8 coal and dolomite in a Foster Wheeler carbonizer. The experiments were conducted under nitrogen and simulated coal gas (SCG), which was a mixture of CO, CO{sub 2}, H{sub 2}S, CH{sub 4}, N{sub 2}, and steam, at 1 and 17 atm. The conversion over these materials under nitrogen was much higher at 17 atm than at 1 atm. At higher pressures, tar molecules were trapped in the pores of the bed material and underwent secondary reactions, resulting in the formation of excess char. However, when nitrogen was replaced by SCG, the reactions that induce char formation were suppressed, thus increasing the yield of gaseous products. The analysis of the gaseous products and the spent bed materials for organic and inorganic carbons suggested that the product distribution can be altered by changing the carrier gas, temperature, and pressure.

  19. Genome Sequence of Azotobacter vinelandii, an Obligate Aerobe Specialized To Support Diverse Anaerobic Metabolic Processes▿ †

    PubMed Central

    Setubal, João C.; dos Santos, Patricia; Goldman, Barry S.; Ertesvåg, Helga; Espin, Guadelupe; Rubio, Luis M.; Valla, Svein; Almeida, Nalvo F.; Balasubramanian, Divya; Cromes, Lindsey; Curatti, Leonardo; Du, Zijin; Godsy, Eric; Goodner, Brad; Hellner-Burris, Kaitlyn; Hernandez, José A.; Houmiel, Katherine; Imperial, Juan; Kennedy, Christina; Larson, Timothy J.; Latreille, Phil; Ligon, Lauren S.; Lu, Jing; Mærk, Mali; Miller, Nancy M.; Norton, Stacie; O'Carroll, Ina P.; Paulsen, Ian; Raulfs, Estella C.; Roemer, Rebecca; Rosser, James; Segura, Daniel; Slater, Steve; Stricklin, Shawn L.; Studholme, David J.; Sun, Jian; Viana, Carlos J.; Wallin, Erik; Wang, Baomin; Wheeler, Cathy; Zhu, Huijun; Dean, Dennis R.; Dixon, Ray; Wood, Derek

    2009-01-01

    Azotobacter vinelandii is a soil bacterium related to the Pseudomonas genus that fixes nitrogen under aerobic conditions while simultaneously protecting nitrogenase from oxygen damage. In response to carbon availability, this organism undergoes a simple differentiation process to form cysts that are resistant to drought and other physical and chemical agents. Here we report the complete genome sequence of A. vinelandii DJ, which has a single circular genome of 5,365,318 bp. In order to reconcile an obligate aerobic lifestyle with exquisitely oxygen-sensitive processes, A. vinelandii is specialized in terms of its complement of respiratory proteins. It is able to produce alginate, a polymer that further protects the organism from excess exogenous oxygen, and it has multiple duplications of alginate modification genes, which may alter alginate composition in response to oxygen availability. The genome analysis identified the chromosomal locations of the genes coding for the three known oxygen-sensitive nitrogenases, as well as genes coding for other oxygen-sensitive enzymes, such as carbon monoxide dehydrogenase and formate dehydrogenase. These findings offer new prospects for the wider application of A. vinelandii as a host for the production and characterization of oxygen-sensitive proteins. PMID:19429624

  20. Performance evaluation of the sulfur-redox-reaction-activated up-flow anaerobic sludge blanket and down-flow hanging sponge anaerobic/anoxic sequencing batch reactor system for municipal sewage treatment.

    PubMed

    Hatamoto, Masashi; Ohtsuki, Kota; Maharjan, Namita; Ono, Shinya; Dehama, Kazuya; Sakamoto, Kenichi; Takahashi, Masanobu; Yamaguchi, Takashi

    2016-03-01

    A sulfur-redox-reaction-activated up-flow anaerobic sludge blanket (UASB) and down-flow hanging sponge (DHS) system, combined with an anaerobic/anoxic sequencing batch reactor (A2SBR), has been used for municipal sewage treatment for over 2 years. The present system achieved a removal rate of 95±14% for BOD, 74±22% for total nitrogen, and 78±25% for total phosphorus, including low water temperature conditions. Sludge conversion rates during the operational period were 0.016 and 0.218 g-VSS g-COD-removed(-1) for the UASB, and DHS, respectively, which are similar to a conventional UASB-DHS system, which is not used of sulfur-redox-reaction, for sewage treatment. Using the sulfur-redox reaction made advanced treatment of municipal wastewater with minimal sludge generation possible, even in winter. Furthermore, the occurrence of a unique phenomenon, known as the anaerobic sulfur oxidation reaction, was confirmed in the UASB reactor under the winter season. Copyright © 2016. Published by Elsevier Ltd.

  1. Anaerobic treatment of complex chemical wastewater in a sequencing batch biofilm reactor: process optimization and evaluation of factor interactions using the Taguchi dynamic DOE methodology.

    PubMed

    Venkata Mohan, S; Chandrasekhara Rao, N; Krishna Prasad, K; Murali Krishna, P; Sreenivas Rao, R; Sarma, P N

    2005-06-20

    The Taguchi robust experimental design (DOE) methodology has been applied on a dynamic anaerobic process treating complex wastewater by an anaerobic sequencing batch biofilm reactor (AnSBBR). For optimizing the process as well as to evaluate the influence of different factors on the process, the uncontrollable (noise) factors have been considered. The Taguchi methodology adopting dynamic approach is the first of its kind for studying anaerobic process evaluation and process optimization. The designed experimental methodology consisted of four phases--planning, conducting, analysis, and validation connected sequence-wise to achieve the overall optimization. In the experimental design, five controllable factors, i.e., organic loading rate (OLR), inlet pH, biodegradability (BOD/COD ratio), temperature, and sulfate concentration, along with the two uncontrollable (noise) factors, volatile fatty acids (VFA) and alkalinity at two levels were considered for optimization of the anae robic system. Thirty-two anaerobic experiments were conducted with a different combination of factors and the results obtained in terms of substrate degradation rates were processed in Qualitek-4 software to study the main effect of individual factors, interaction between the individual factors, and signal-to-noise (S/N) ratio analysis. Attempts were also made to achieve optimum conditions. Studies on the influence of individual factors on process performance revealed the intensive effect of OLR. In multiple factor interaction studies, biodegradability with other factors, such as temperature, pH, and sulfate have shown maximum influence over the process performance. The optimum conditions for the efficient performance of the anaerobic system in treating complex wastewater by considering dynamic (noise) factors obtained are higher organic loading rate of 3.5 Kg COD/m3 day, neutral pH with high biodegradability (BOD/COD ratio of 0.5), along with mesophilic temperature range (40 degrees C), and

  2. Biodegradation of industrial-strength 2,4-dichlorophenoxyacetic acid wastewaters in the presence of glucose in aerobic and anaerobic sequencing batch reactors.

    PubMed

    Elefsiniotis, Panagiotis; Wareham, David G

    2013-01-01

    This research explored the biodegradability of 2,4-dichlorophenoxyacetic acid (2,4-D) in two laboratory-scale sequencing batch reactors (SBRs) that operated under aerobic and anaerobic conditions. The potential limit of 2,4-D degradation was investigated at a hydraulic retention time of 48 h, using glucose as a supplemental substrate and increasing feed concentrations of 2,4-D; namely 100 to 700 mg/L (i.e. industrial strength) for the aerobic system and 100 to 300 mg/L for the anaerobic SBR. The results revealed that 100 mg/L of 2,4-D was completely degraded following an acclimation period of 29 d (aerobic SBR) and 70 d (anaerobic SBR). The aerobic system achieved total 2,4-D removal at feed concentrations up to 600 mg/L which appeared to be a practical limit, since a further increase to 700 mg/L impaired glucose degradation while 2,4-D biodegradation was non-existent. In all cases, glucose was consumed before the onset of 2,4-D degradation. In the anaerobic SBR, 2,4-D degradation was limited to 120 mg/L.

  3. Integration of ozonation and an anaerobic sequencing batch reactor (AnSBR) for the treatment of cherry stillage.

    PubMed

    Alvarez, Pedro M; Beltrán, Fernando J; Rodríguez, Eva M

    2005-01-01

    Cherry stillage is a high strength organic wastewater arising from the manufacture of alcoholic products by distillation of fermented cherries. It is made up of biorefractory polyphenols in addition to readily biodegradable organic matter. An anaerobic sequencing batch reactor (AnSBR) was used to treat cherry stillage at influent COD ranging from 5 to 50 g/L. Different cycle times were selected to test biomass organic loading rates (OLR(B)), from 0.3 to 1.2 g COD/g VSS.d. COD and TOC efficiency removals higher than 80% were achieved at influent COD up to 28.5 g/L but minimum OLR(B) tested. However, as a result of the temporary inhibition of acetogens and methanogens, volatile fatty acids (VFA) noticeably accumulated and methane production came to a transient standstill when operating at influent COD higher than 10 g/L. At these conditions, the AnSBR showed signs of instability and could not operate efficiently at OLR(B) higher than 0.3 g COD/g VSS.d. A feasible explanation for this inhibition is the presence of toxic polyphenols in cherry stillage. Thus, an ozonation step prior to the AnSBR was observed to be useful, since more than 75% of polyphenols could be removed by ozone. The integrated process was shown to be a suitable treatment technology as the following advantages compared to the single AnSBR treatment were observed: greater polyphenols and color removals, higher COD and TOC removal rates thus enabling the process to effectively operate at higher OLR, higher degree of biomethanation, and good stability with less risk of acidification.

  4. Effects of manipulating cyclic duration and pH on fermentative hydrogen production in an anaerobic sequencing batch reactor.

    PubMed

    Won, Seung-Gun; Lau, Anthony K

    2015-01-01

    The effects of cyclic duration and pH on biological hydrogen production were investigated in an anaerobic sequencing batch reactor. Experiments were conducted using cyclic duration of (4, 8, and 12 h) in combination with pH (4, 5, and 6) in a 3 × 3 factorial design, while hydraulic retention time and organic loading rate were maintained at 24 h and 10.3 g COD L(-1).d(-1), respectively. At pH 4, the effect of cyclic duration on hydrogen production was found to be insignificant. However, in runs with pH 5 and 6, a shorter cyclic duration of 4 h led to lower hydrogen productivity. The operational condition (pH 6, cyclic duration 12 h) induced higher hydrogen production rate of 2.3 ± 0.6 L H2/L reactor.d, whereas higher hydrogen yield of 2.2 ± 0.4 mol H2/mol sucrose was achieved at pH 5 and the same 12 h cyclic duration. The differences in hydrogen production were not statistically significant between 8 h and 12 h cyclic duration. Higher hydrogen production rates were associated with biomass (mixed liquor volatile suspended solids) concentration ranging from 8-13 g L(-1), but further increase in biomass growth was not accompanied by increased hydrogen production. Furthermore, a food-to-microorganism ratio of 0.84 was found to result in higher hydrogen production rate.

  5. Optimization of the pyrolysis process of empty fruit bunch (EFB) in a fixed-bed reactor through a central composite design (CCD)

    NASA Astrophysics Data System (ADS)

    Mohamed, Alina Rahayu; Hamzah, Zainab; Daud, Mohamed Zulkali Mohamed

    2014-07-01

    The production of crude palm oil from the processing of palm fresh fruit bunches in the palm oil mills in Malaysia hs resulted in a huge quantity of empty fruit bunch (EFB) accumulated. The EFB was used as a feedstock in the pyrolysis process using a fixed-bed reactor in the present study. The optimization of process parameters such as pyrolysis temperature (factor A), biomass particle size (factor B) and holding time (factor C) were investigated through Central Composite Design (CCD) using Stat-Ease Design Expert software version 7 with bio-oil yield considered as the response. Twenty experimental runs were conducted. The results were completely analyzed by Analysis of Variance (ANOVA). The model was statistically significant. All factors studied were significant with p-values < 0.05. The pyrolysis temperature (factor A) was considered as the most significant parameter because its F-value of 116.29 was the highest. The value of R2 was 0.9564 which indicated that the selected factors and its levels showed high correlation to the production of bio-oil from EFB pyrolysis process. A quadratic model equation was developed and employed to predict the highest theoretical bio-oil yield. The maximum bio-oil yield of 46.2 % was achieved at pyrolysis temperature of 442.15 °C using the EFB particle size of 866 μm which corresponded to the EFB particle size in the range of 710-1000 μm and holding time of 483 seconds.

  6. Optimization of the pyrolysis process of empty fruit bunch (EFB) in a fixed-bed reactor through a central composite design (CCD)

    SciTech Connect

    Mohamed, Alina Rahayu; Hamzah, Zainab; Daud, Mohamed Zulkali Mohamed

    2014-07-10

    The production of crude palm oil from the processing of palm fresh fruit bunches in the palm oil mills in Malaysia hs resulted in a huge quantity of empty fruit bunch (EFB) accumulated. The EFB was used as a feedstock in the pyrolysis process using a fixed-bed reactor in the present study. The optimization of process parameters such as pyrolysis temperature (factor A), biomass particle size (factor B) and holding time (factor C) were investigated through Central Composite Design (CCD) using Stat-Ease Design Expert software version 7 with bio-oil yield considered as the response. Twenty experimental runs were conducted. The results were completely analyzed by Analysis of Variance (ANOVA). The model was statistically significant. All factors studied were significant with p-values < 0.05. The pyrolysis temperature (factor A) was considered as the most significant parameter because its F-value of 116.29 was the highest. The value of R{sup 2} was 0.9564 which indicated that the selected factors and its levels showed high correlation to the production of bio-oil from EFB pyrolysis process. A quadratic model equation was developed and employed to predict the highest theoretical bio-oil yield. The maximum bio-oil yield of 46.2 % was achieved at pyrolysis temperature of 442.15 °C using the EFB particle size of 866 μm which corresponded to the EFB particle size in the range of 710–1000 μm and holding time of 483 seconds.

  7. Adsorption behavior of levulinic acid onto microporous hyper-cross-linked polymers in aqueous solution: Equilibrium, thermodynamic, kinetic simulation and fixed-bed column studies.

    PubMed

    Lin, Xiaoqing; Huang, Qianlin; Qi, Gaoxiang; Xiong, Lian; Huang, Chao; Chen, Xuefang; Li, Hailong; Chen, Xinde

    2017-03-01

    The recovery of levulinic acid (LA) from aqueous solution and actual biomass hydrolysate by a microporous hyper-cross-linked polymer, SY-01, was investigated for the first time under batch and fixed-bed column conditions. The results showed that the optimum pH should be in the acidic range (pH < 3.0) without adjusting the pH. In the single-component system equilibrium study, the Langmuir isotherm model fits the LA adsorption onto SY-01 resin better than the Freundlich isotherm model, indicating that LA adsorption onto SY-01 resin under the concentration range studied is a monolayer homogeneous adsorption process. The maximum adsorption capacity of LA onto SY-01 resin decreased with increasing temperature, ranging from 103.74 to 95.70 mg/g. The obtained thermodynamic parameters suggested that the adsorption of LA on SY-01 was spontaneous (ΔG(0)<-3.788 kJ/mol), and exothermic (ΔH(0) = -11.764 kJ/mol). For kinetic study, the adsorption of LA onto SY-01 resin at various operating conditions follows the pore diffusion model and the intraparticle diffusion is the rate-limiting step for the adsorption of LA onto SY-01 resin. The effective pore diffusivity was dependent upon temperature, but independent of initial LA concentration, and were 3.306 × 10(-10), 5.274 × 10(-10) and 7.707 × 10(-10) m(2)/s at 298, 318 and 338 K, respectively. In desorption process, the recovery efficiency of LA from SY-01 resin was 99.39%, and LA concentration in the eluent was raised 2.97-fold. In conclusion, our results show that the SY-01 resin has potential application in product recovery of LA from biomass hydrolysate.

  8. Techno-economic analysis of sorption-enhanced steam methane reforming in a fixed bed reactor network integrated with fuel cell

    NASA Astrophysics Data System (ADS)

    Diglio, Giuseppe; Hanak, Dawid P.; Bareschino, Piero; Mancusi, Erasmo; Pepe, Francesco; Montagnaro, Fabio; Manovic, Vasilije

    2017-10-01

    Sorption-enhanced steam methane reforming (SE-SMR) is a promising alternative for H2 production with inherent CO2 capture. This study evaluates the techno-economic performance of SE-SMR in a network of fixed beds and its integration with a solid oxide fuel cell (SE-SMR-SOFC) for power generation. The analysis revealed that both proposed systems are characterised by better economic performance than the reference systems. In particular, for SE-SMR the levelised cost of hydrogen is 1.6 €ṡkg-1 and the cost of CO2 avoided is 29.9 €ṡtCO2-1 (2.4 €ṡkg-1 and 50 €ṡtCO2-1, respectively, for SMR with CO2 capture) while for SE-SMR-SOFC the levelised cost of electricity is 0.078 €ṡkWh-1 and the cost of CO2 avoided is 36.9 €ṡtCO2-1 (0.080 €ṡkWh-1 and 80 €ṡtCO2-1, respectively, for natural gas-fired power plant with carbon capture). The sensitivity analysis showed that the specific cost of fuel and the capital cost of fuel cell mainly affect the economic performance of SE-SMR and SE-SMR-SOFC, respectively. The daily revenue of the SE-SMR-SOFC system is higher than that of the natural gas-fired power plant if the difference between the carbon tax and the CO2 transport and storage cost is > 6 €ṡtCO2-1.

  9. AsIII oxidation by Thiomonas arsenivorans in up-flow fixed-bed reactors coupled to As sequestration onto zero-valent iron-coated sand.

    PubMed

    Wan, Junfeng; Klein, Jonathan; Simon, Stephane; Joulian, Catherine; Dictor, Marie-Christine; Deluchat, Véronique; Dagot, Christophe

    2010-09-01

    The combined processes of biological As(III) oxidation and removal of As(III) and As(V) by zero-valent iron were investigated with synthetic water containing high As(III) concentration (10 mg L(-1)). Two up-flow fixed-bed reactors (R1 and R2) were filled with 2 L of sieved sand (d = 3 ± 1 mm) while zero-valent iron powder (d = 76 μm; 1% (w/w) of sand) was mixed evenly with sand in R2. Thiomonas arsenivorans was inoculated in the two reactors. The pilot unit was studied for 33 days, with HRT of 4 and 1 h. The maximal As(III) oxidation rate was 8.36 mg h(-1) L(-1) in R1 and about 45% of total As was removed in R2 for an HRT of 1 h. A first order model fitted well with the As(III) concentration evolution at the different levels in R1. At the end of the pilot monitoring, batch tests were conducted with support collected at different levels in R1. They showed that bacterial As(III) oxidation rate was correlated with the axial length of reactor, which could be explained by biomass distribution in reactor or by bacterial activity. In opposition, As(III) oxidation rate was not stable in R2 due to the simultaneous bacterial As(III) oxidation and chemical removal by zero-valent iron and its oxidant products. However, a durable removal of total As was realized and zero-valent iron was not saturated by As over 33 days in R2. Furthermore, the influence of zero-valent iron and its oxidant corrosion products on the evolution of As(III)-oxidizing bacteria diversity was highlighted by the molecular fingerprinting method of PCR-DGGE using aoxB gene as a functional marker of aerobic As(III) oxidizers.

  10. Examination of sulfur-functionalized, copper-doped iron nanoparticles for vapor-phase mercury capture in entrained-flow and fixed-bed systems

    SciTech Connect

    D.E. Meyer; S.K. Sikdar; N.D. Hutson; D. Bhattacharyya

    2007-09-15

    The use of copper-doped Fe nanoaggregates silanized with organic sulfur as bis-(triethoxy silyl propyl)-tetra sulfide has been investigated for the capture of elemental mercury (Hg{sup 0}) from the vapor phase for potential power plant applications. Silanization procedures resulted in 70% deposition of the targeted sulfur level, with particles containing approximately 4 wt % S. The addition of copper was found to increase the fixed-bed (total) capacity of this type of sorbent from 170 {+-} {mu}20 g Hg{center_dot}g sorbent{sup -1} with no copper doping to 2730 {+-} 80 {mu}g Hg{center_dot}g sorbent{sup -1} at 1.2 wt % Cu. When no S is deposited, the capacity of Fe/Cu nanoaggregates was only 180 g Hg{center_dot}g sorbent{sup -1}. These findings suggest that a combined Cu-S mechanism is responsible for Hg capture. Moving-bed (injection) testing of the Fe-based sorbents in a simulated flue gas stream showed that the 1.2 wt % Cu sample was able to achieve significant removal of the Hg. At a modest sorbent injection rate of 3.6 x 10{sup -3} g{center_dot}L{sup -1}{center_dot}h{sup -1}, this material showed a steady-state removal capacity of 107.5 {mu}g Hg{center_dot}g sorbent{sup -1} for an inlet concentration of 17.8 {mu}g{center_dot}m{sup -3}. On the basis of only 4% usage of the total capacity during single-pass injection, it might be beneficial to develop methods to separate and recycle these materials to reduce power plant operation costs for Hg emissions control. 17 refs., 5 figs., 10 tabs.

  11. Effect of rice husk ash mass on sustainability pyrolysis zone of fixed bed downdraft gasifier with capacity of 10 kg/hour

    NASA Astrophysics Data System (ADS)

    Surjosatyo, Adi; Haq, Imaduddin; Dafiqurrohman, Hafif; Gibran, Felly Rihlat

    2017-03-01

    The formation of pyrolysis sustainability (Sustainable Pyrolysis) is the objective of the gasification process. Pyrolysis zone in the gasification process is the result of the endothermic reaction that get heat from oxidation (combustion) of the fuel with oxygen, where cracking biomass rice husk result of such as charcoal, water vapor, steam tar, and gas - gas (CO, H 2, CH 4, CO 2 and N 2) and must be maintained at a pyrolysis temperature to obtain results plentiful gas (producer gas) or syngas (synthetic gas). Obtaining continuously syngas is indicated by flow rate (discharge) producer gas well and the consistency of the flame on the gas burner, it is highly influenced by the gasification process and the operation of the gasifier and the mass balance (mass balance) between the feeding rate of rice husk with the disposal of ash (ash removal). In experiments conducted is using fixed bed gasifier type downdraft capacity of 10 kg/h. Besides setting the mass of rice husks into the gasifier and disposal arrangements rice husk ash may affect the sustainability of the pyrolysis process, but tar produced during the gasification process causes sticky rice husk ash in the plenum gasifier. Modifications disposal system rice husk ash can facilitate the arrangement of ash disposal then could control the temperature pyrolysis with pyrolysis at temperatures between 500-750 ° C. The experimental study was conducted to determine the effect of mass quantities of rice husk ash issued against sustainability pyrolysis temperature which is obtained at each time disposal of rice husk ash to produce 60-90 grams of ash issued. From some experimental phenomena is expected to be seen pyrolysis and its effect on the flow rate of syngas and the stability of the flame on the gas burner so that this research can find a correlation to obtain performance (performance) gasifier optimal.

  12. Genome Sequence of the Deltaproteobacterial Strain NaphS2 and Analysis of Differential Gene Expression during Anaerobic Growth on Naphthalene

    SciTech Connect

    DiDonato, Raymond J.; Young, Nelson D.; Butler, Jessica; Chin, Kuk-Jeong; Hixson, Kim K.; Mouser, Paula; Lipton, Mary S.; DeBoy, Robert; Methe, Barbara

    2010-11-19

    Anaerobic polycyclic hydrocarbon (PAH) degradation coupled to sulfate reduction may be an important mechanism for in situ remediation of contaminated sediments. Steps involved in the anaerobic degradation of 2-methylnaphthalene have been described in the sulfate reducing strains NaphS3, NaphS6 and N47. Evidence from N47 suggests that naphthalene degradation involves 2-methylnaphthalene as an intermediate, whereas evidence in NaphS2, NaphS3 and NaphS6 suggests a mechanism for naphthalene degradation that does not involve 2-methylnaphthalene. To further characterize pathways involved in naphthalene degradation in NaphS2, the draft genome was sequenced, and gene and protein expression examined.

  13. Study of the diversity of microbial communities in a sequencing batch reactor oxic-settling-anaerobic process and its modified process.

    PubMed

    Sun, Lianpeng; Chen, Jianfan; Wei, Xiange; Guo, Wuzhen; Lin, Meishan; Yu, Xiaoyu

    2016-05-01

    To further reveal the mechanism of sludge reduction in the oxic-settling-anaerobic (OSA) process, the polymerase chain reaction - denaturing gradient gel electrophoresis protocol was used to study the possible difference in the microbial communities between a sequencing batch reactor (SBR)-OSA process and its modified process, by analyzing the change in the diversity of the microbial communities in each reactor of both systems. The results indicated that the structure of the microbial communities in aerobic reactors of the 2 processes was very different, but the predominant microbial populations in anaerobic reactors were similar. The predominant microbial population in the aerobic reactor of the SBR-OSA belonged to Burkholderia cepacia, class Betaproteobacteria, while those of the modified process belonged to the classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. These 3 types of microbes had a cryptic growth characteristic, which was the main cause of a greater sludge reduction efficiency achieved by the modified process.

  14. Development of standardized air-blown coal gasifier/gas turbine concepts for future electric power systems. Volume 2, Appendix A: Fixed bed gasifier and sulfur sorbent regeneration subsystem computer model development: Final report

    SciTech Connect

    Blough, E.; Russell, W.; Leach, J.W.

    1990-08-01

    Computer models have been developed for evaluating conceptual designs of integrated coal gasification combined cycle power plants. An overall system model was developed for performing thermodynamic cycle analyses, and detailed models were developed for predicting performance characteristics of fixed bed coal gasifiers and hot gas clean up subsystem components. The overall system model performs mass and energy balances and does chemical equilibrium analyses to determine the effects of changes in operating conditions, or to evaluate proposed design changes. An existing plug flow model for fixed bed gasifiers known as the Wen II model was revised and updated. Also, a spread sheet model of zinc ferrite sulfur sorbent regeneration subsystem was developed. Parametric analyses were performed to determine how performance depends on variables in the system design. The work was done to support CRS Sirrine Incorporated in their study of standardized air blown coal gasifier gas turbine concepts.

  15. Metal-organic framework based upon the synergy of a Brønsted acid framework and Lewis acid centers as a highly efficient heterogeneous catalyst for fixed-bed reactions.

    PubMed

    Li, Baiyan; Leng, Kunyue; Zhang, Yiming; Dynes, James J; Wang, Jian; Hu, Yongfeng; Ma, Dingxuan; Shi, Zhan; Zhu, Liangkui; Zhang, Daliang; Sun, Yinyong; Chrzanowski, Matthew; Ma, Shengqian

    2015-04-01

    We report a strategy of combining a Brønsted acid metal-organic framework (MOF) with Lewis acid centers to afford a Lewis acid@Brønsted acid MOF with high catalytic activity, as exemplified in the context of MIL-101-Cr-SO3H·Al(III). Because of the synergy between the Brønsted acid framework and the Al(III) Lewis acid centers, MIL-101-Cr-SO3H·Al(III) demonstrates excellent catalytic performance in a series of fixed-bed reactions, outperforming two benchmark zeolite catalysts (H-Beta and HMOR). Our work therefore not only provides a new approach to achieve high catalytic activity in MOFs but also paves a way to develop MOFs as a new type of highly efficient heterogeneous catalysts for fixed-bed reactions.

  16. Efficient recovery of carbon dioxide from flue gases of coal-fired power plants by cyclic fixed-bed operations over K{sub 2}CO{sub 3}-on-carbon

    SciTech Connect

    Hayashi, Hiromu; Taniuchi, Jun; Furuyashiki, Nobuyoshi; Sugiyama, Shigeru; Hirano, Shinichi; Shigemoto, Naoya; Nonaka, Takazumi

    1998-01-01

    An efficient chemical absorption method capable of cyclic fixed-bed operations under moist conditions for the recovery of carbon dioxide from flue gases has been proposed employing K{sub 2}CO{sub 3}-on-carbon. Carbon dioxide was chemically absorbed by the reaction K{sub 2}CO{sub 3} + CO{sub 2} + H{sub 2}O {r_equilibrium} 2KHCO{sub 3} to form potassium hydrogen carbonate. Moisture, usually contained as high as 8--17% in flue gases, badly affects the capacity of conventional adsorbents such as zeolites, but the present technology has no concern with moisture; water is rather necessary in principle as shown in the equation above. Deliquescent potassium carbonate should be supported on an appropriate porous material to adapt for fixed-bed operations. After breakthrough of carbon dioxide, the entrapped carbon dioxide was released by the decomposition of hydrogen carbonate to shift the reaction in reverse on flushing with steam, which could be condensed by cooling to afford carbon dioxide in high purity. Among various preparations of alkaline-earth carbonates (X{sub 2}CO{sub 3}, X = Li, Na, K) on porous materials, K{sub 2}CO{sub 3}-on-activated carbon revealed excellent properties for the present purpose. Preparation and characterization of K{sub 2}CO{sub 3}-on-carbon and illustrative fixed-bed operations under flue gas conditions in laboratory columns and a bench-scale plant are described.

  17. Anaerobic biodegradation of cyanide under methanogenic conditions

    SciTech Connect

    Fallon, R.D.; Cooper, D.A.; Henson, M. ); Speece, R. )

    1991-06-01

    Upflow, anaerobic, fixed-bed, activated charcoal biotreatment columns capable of operating at free cyanide concentrations of {gt}100 mg liter{sup {minus}1} with a hydraulic retention time of {lt}48 h were developed. Methanogenesis was maintained under a variety of feed medium conditions which included ethanol, phenol, or methanol as the primary reduced carbon source. Under optimal conditions, {gt}70% of the inflow free cyanide was removed in the first 30% of the column height. Strongly complexed cyanides were resistant to removal. Ammonia was the nitrogen end product of cyanide transformation. In cell material removed from the charcoal columns, ({sup 14}C) bicarbonate was the major carbon end product of ({sup 14}C) cyanide transformation.

  18. Anaerobic biodegradation of cyanide under methanogenic conditions.

    PubMed Central

    Fallon, R D; Cooper, D A; Speece, R; Henson, M

    1991-01-01

    Upflow, anaerobic, fixed-bed, activated charcoal biotreatment columns capable of operating at free cyanide concentrations of greater than 100 mg liter-1 with a hydraulic retention time of less than 48 h were developed. Methanogenesis was maintained under a variety of feed medium conditions which included ethanol, phenol, or methanol as the primary reduced carbon source. Under optimal conditions, greater than 70% of the inflow free cyanide was removed in the first 30% of the column height. Strongly complexed cyanides were resistant to removal. Ammonia was the nitrogen end product of cyanide transformation. In cell material removed from the charcoal columns, [14C]bicarbonate was the major carbon end product of [14C]cyanide transformation. PMID:1872600

  19. Effect of feeding strategy on the stability of anaerobic sequencing batch reactor responses to organic loading conditions.

    PubMed

    Cheong, Dae-Yeol; Hansen, Conly L

    2008-07-01

    The goal of this study was to examine the effect of feeding strategy on the capability for treatment and the stability of an anaerobic sequencing batch reactor (ASBR) under increasing organic loading. The lab-scale ASBR systems were operated at 35 degrees C using synthetic organic wastewater under both batch and fed-batch operational modes with different feed to cycle time (F:C) ratios. Experimental studies were conducted over a wide range of volumetric organic loading rates (VOLRs) (1.524 g COD/l/d) by varying the hydraulic retention time (HRT) (1.25, 2.5, and 5d) and the feed wastewater's COD (3750-30,000 mg/l). With an F:C ratio greater than or equal to 0.42, the fed-batch mode operation showed higher system efficiency in COD removal, volumetric methane production rate (VMPR), and specific methane production rate (SMPR) as compared to those in the batch mode with identical VOLR and HRT. In the fed-batch mode, the COD removals reached 86-95% with VOLR up to 12 g COD/l/d. The maximums for VMPR of 3.17 l CH4/l/d and for SMPR of 1.63 g CH4-COD/g VSS/d were achieved with a VOLR of 12 g COD/l/d at HRTs of 2.5 and 1.25 d, respectively. The fed-batch operation presented a lower concentration of volatile fatty acids (VFAs) than those in the batch operation. A lower concentration of VFAs confirmed the stability and efficiency of the fed-batch mode operation. The specific methanogenic activity (SMA) analysis showed that the VFA-degrading activity of the biomass in the fed-batch mode was higher for acetate and butyrate, and lower for propionate. Determined biomass yield and bacterial decay coefficients in the fed-batch operational mode were 0.05 g VSS/g COD rem and 0.001 d(-1), respectively.

  20. Genome Sequence of the Facultative Anaerobic Arsenite-Oxidizing and Nitrate-Reducing Bacterium Acidovorax sp. Strain NO1

    PubMed Central

    Huang, Yinyan; Li, Hang; Rensing, Christopher; Zhao, Kai; Johnstone, Laurel

    2012-01-01

    Acidovorax sp. strain NO1, isolated from gold mine soil, was shown to be a facultative anaerobic arsenite-oxidizing and nitrate-reducing bacterium. The reported draft genome predicts the presence of genes involved in arsenic metabolism, nitrate reduction, phosphate transport, and multiple metal resistances and indicates putative horizontal gene transfer events. PMID:22374962

  1. Non-contiguous finished genome sequence and description of Fenollaria massiliensis gen. nov., sp. nov., a new genus of anaerobic bacterium

    PubMed Central

    Pagnier, Isabelle; Croce, Olivier; Robert, Catherine; Raoult, Didier; La Scola, Bernard

    2014-01-01

    Fenollaria massiliensis strain 9401234T, is the type strain of Fenollaria massiliensis gen. nov., sp. nov., a new species within a new genus Fenollaria. This strain, whose genome is described here, was isolated from an osteoarticular sample. F. massiliensis strain 9401234T is an obligate anaerobic Gram-negative bacillus. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 1.71 Mbp long genome exhibits a G+C content of 34.46% and contains 1,667 protein-coding and 30 RNA genes, including 3 rRNA genes. PMID:25197455

  2. Design of a fixed-bed ion-exchange process for the treatment of rinse waters generated in the galvanization process using Laminaria hyperborea as natural cation exchanger.

    PubMed

    Mazur, Luciana P; Pozdniakova, Tatiana A; Mayer, Diego A; Boaventura, Rui A R; Vilar, Vítor J P

    2016-03-01

    In this study, the removal of zinc from galvanization wastewaters was performed in a fixed bed column packed with brown macro-algae Laminaria hyperborea, acting as a natural cation exchanger (resin). The rinse wastewater presents a zinc concentration between 9 and 22 mg/L, a high concentration of light metals (mainly Na and Ca), a high conductivity (0.5-1.5 mS/cm) and a low organic content (DOC = 7-15 mg C/L). The zinc speciation diagram showed that approximately 80% of zinc is in the form of Zn(2+) and ≅20% as ZnSO4, considering the effluent matrix. From all operational conditions tested for zinc uptake (17 < bed height<27 cm, 4.5 < flow rate<18.2 BV/h, 0.8 < particle equivalent diameter<2.0 mm), the highest useful capacity (7.1 mg Zn/g algae) was obtained for D/dp = 31, L/D = 11, 9.1 BV/h, τ = 6.4 min, corresponding to a service capacity of 124 BV (endpoint of 2 mg Zn/L). Elution was faster and near to 100% effective using 10 BV of HCl (1 M, 3.0%, 363 g HCl/L of resin), for flow rates higher than 4.5 BV/h. Calcium chloride solution (0.1 M) was selected as the best regenerant, allowing the reuse of the natural resin for more than 3 saturation/elution/regeneration cycles. The best operation conditions were scaled-up and tested in a pre-pilot plant. The scale-up design of the cation exchange process was proposed for the treatment of 2.4 m(3)/day of galvanization wastewater, resulting in an estimated reactants cost of 2.44 €/m(3).

  3. Improvement of bio-oil yield and quality in co-pyrolysis of corncobs and high density polyethylene in a fixed bed reactor at low heating rate

    NASA Astrophysics Data System (ADS)

    Supramono, D.; Lusiani, S.

    2016-11-01

    Over the past few decades, interest in developing biomass-derived fuel has been increasing rapidly due to the decrease in fossil fuel reserves. Bio-oil produced by biomass pyrolysis however contains high oxygen compounds resulting in low calorific-value fuel and therefore requiring upgrading. In co-pyrolysis of the feed blend of plastics of High Density Polyethylene (HDPE) and biomass of com cob particles, at some compositions free radicals from plastic decomposition containing more hydrogen radicals are able to bond oxygen radicals originating from biomass to reduce oxygenate compounds in the bio-oil thus increasing bio-oil quality. This phenomenon is usually called synergetic effect. In addition to that, the pattern of heating of the feed blend in the pyrolysis reactor is predicted to affect biooil quality and yield. In a batch reactor, co-pyrolysis of corncobs and HDPE requires low heating rate to reach a peak temperature at temperature rise period followed by heating for some time at peak temperature called holding time at constant temperature period. No research has been carried out to investigate how long holding time is set in co-pyrolysis of plastic and biomass to obtain high yield of bio-oil. Holding time may affect either crosslinking of free radicals in gas phase, which increases char product, or secondary pyrolysis in the gas phase, which increases non-condensable gas in the gas phase of pyrolysis reactor, both of which reduce bio-oil yield. Therefore, holding time of co-pyrolysis affects the mass rate of bio-oil formation as the pyrolysis proceeds and quality of the bio-oil. In the present work, effects of holding time on the yield and quality of bio-oil have been investigated using horizontal fixed bed of the feed blends at heating rate of 5°C, peak temperature of 500°C and N2 flow rate of 700 ml/minute. Holding time was varied from 0 to 70 minutes with 10 minutes interval. To investigate the effects of holding time, the composition of HDPE in the

  4. Anaerobic bacteria

    MedlinePlus

    Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  5. Carbon and nitrogen removal from a wastewater of an industrial dairy laboratory with a coupled anaerobic filter-sequencing batch reactor system.

    PubMed

    Garrido, J M; Omil, F; Arrojo, B; Méndez, R; Lema, J M

    2001-01-01

    A set of two reactors, an Anaerobic Filter (AF) of 12 m3 and a Sequencing Batch Reactor (SBR) of 28 m3, coupled in series, were used to treat the wastewaters from an industrial milk analysis laboratory. The characteristics of these effluents are similar to those discharged by dairy factories (average values around 10 kg COD/m3 and 0.20 kg N/m3). These wastewaters were produced as the result of the final mixture of the analysed milk samples, with a very high organic load, and other low strength effluents, such as sewage and other minor liquid streams generated in the laboratory. Two microbial growth inhibitors, sodium azide and chloramphenicol, were systematically added to the milk before its analysis. Preliminary results have shown that these compounds did apparently not inhibit the methanogenic activity of the anaerobic sludge. Toxicity determination, using the Microtox method, resulted in EC50 values for the wastewaters of 20 g/L, whereas the final effluent from the SBR was non toxic. A maximum OLR of 8 kg COD/m3.d was treated in the AF, being the maximum OLR in the SBR around 1.5-2 kg COD/m3.d. During operation, the soluble COD of the final effluent from the SBR was usually below 200 mg/L, and total nitrogen (mainly nitrate) below 10 mg N/L. Assimilation of nitrogen for growth and nitrification-denitrification were the main mechanisms of nitrogen removal from the wastewater. In the anaerobic system between 50-85% of the organic matter was converted into methane, being the remaining COD and most of the nitrogen removed in the suspended culture system. Overall COD removal in the treatment system was 98% and the nitrogen removal up to 99%. The combination of the AF and the SBR was advantageous resulting in a lower energy consumption and sludge generation in the treatment system.

  6. Draft Genome Sequence of Natranaerobius trueperi DSM 18760(T), an Anaerobic, Halophilic, Alkaliphilic, Thermotolerant Bacterium Isolated from a Soda Lake.

    PubMed

    Guo, Xiaomeng; Liao, Ziya; Holtzapple, Mark; Hu, Qingping; Zhao, Baisuo

    2017-09-07

    The anaerobic, halophilic, alkaliphilic, thermotolerant bacterium Natranaerobius trueperi was isolated from a soda lake in Wadi An Natrun, Egypt. It grows optimally at 3.7 M Na(+), pH 9.5, and 43°C. The draft genome consists of 2.63 Mb and is composed of 2,681 predicted genes. Genomic analysis showed that various genes are potentially involved in the adaptation mechanisms for osmotic stress, pH homeostasis, and high temperatures. Copyright © 2017 Guo et al.

  7. Genome sequence of the deltaproteobacterial strain NaphS2 and analysis of differential gene expression during anaerobic growth on naphthalene.

    PubMed

    DiDonato, Raymond J; Young, Nelson D; Butler, Jessica E; Chin, Kuk-Jeong; Hixson, Kim K; Mouser, Paula; Lipton, Mary S; DeBoy, Robert; Methé, Barbara A

    2010-11-19

    Anaerobic polycyclic hydrocarbon (PAH) degradation coupled to sulfate reduction may be an important mechanism for in situ remediation of contaminated sediments. Steps involved in the anaerobic degradation of 2-methylnaphthalene have been described in the sulfate reducing strains NaphS3, NaphS6 and N47. Evidence from N47 suggests that naphthalene degradation involves 2-methylnaphthalene as an intermediate, whereas evidence in NaphS2, NaphS3 and NaphS6 suggests a mechanism for naphthalene degradation that does not involve 2-methylnaphthalene. To further characterize pathways involved in naphthalene degradation in NaphS2, the draft genome was sequenced, and gene and protein expression examined. Draft genome sequencing, gene expression analysis, and proteomic analysis revealed that NaphS2 degrades naphthoyl-CoA in a manner analogous to benzoyl-CoA degradation. Genes including the previously characterized NmsA, thought to encode an enzyme necessary for 2-methylnaphthalene metabolism, were not upregulated during growth of NaphS2 on naphthalene, nor were the corresponding protein products. NaphS2 may possess a non-classical dearomatizing enzyme for benzoate degradation, similar to one previously characterized in Geobacter metallireducens. Identification of genes involved in toluene degradation in NaphS2 led us to determine that NaphS2 degrades toluene, a previously unreported capacity. The genome sequence also suggests that NaphS2 may degrade other monoaromatic compounds. This study demonstrates that steps leading to the degradation of 2-naphthoyl-CoA are conserved between NaphS2 and N47, however while NaphS2 possesses the capacity to degrade 2-methylnaphthalene, naphthalene degradation likely does not proceed via 2-methylnaphthalene. Instead, carboxylation or another form of activation may serve as the first step in naphthalene degradation. Degradation of toluene and 2-methylnaphthalene, and the presence of at least one bss-like and bbs-like gene cluster in this organism

  8. Genome Sequence of the Deltaproteobacterial Strain NaphS2 and Analysis of Differential Gene Expression during Anaerobic Growth on Naphthalene

    PubMed Central

    DiDonato, Raymond J.; Young, Nelson D.; Butler, Jessica E.; Chin, Kuk-Jeong; Hixson, Kim K.; Mouser, Paula; Lipton, Mary S.; DeBoy, Robert; Methé, Barbara A.

    2010-01-01

    Background Anaerobic polycyclic hydrocarbon (PAH) degradation coupled to sulfate reduction may be an important mechanism for in situ remediation of contaminated sediments. Steps involved in the anaerobic degradation of 2-methylnaphthalene have been described in the sulfate reducing strains NaphS3, NaphS6 and N47. Evidence from N47 suggests that naphthalene degradation involves 2-methylnaphthalene as an intermediate, whereas evidence in NaphS2, NaphS3 and NaphS6 suggests a mechanism for naphthalene degradation that does not involve 2-methylnaphthalene. To further characterize pathways involved in naphthalene degradation in NaphS2, the draft genome was sequenced, and gene and protein expression examined. Results Draft genome sequencing, gene expression analysis, and proteomic analysis revealed that NaphS2 degrades naphthoyl-CoA in a manner analogous to benzoyl-CoA degradation. Genes including the previously characterized NmsA, thought to encode an enzyme necessary for 2-methylnaphthalene metabolism, were not upregulated during growth of NaphS2 on naphthalene, nor were the corresponding protein products. NaphS2 may possess a non-classical dearomatizing enzyme for benzoate degradation, similar to one previously characterized in Geobacter metallireducens. Identification of genes involved in toluene degradation in NaphS2 led us to determine that NaphS2 degrades toluene, a previously unreported capacity. The genome sequence also suggests that NaphS2 may degrade other monoaromatic compounds. Conclusion This study demonstrates that steps leading to the degradation of 2-naphthoyl-CoA are conserved between NaphS2 and N47, however while NaphS2 possesses the capacity to degrade 2-methylnaphthalene, naphthalene degradation likely does not proceed via 2-methylnaphthalene. Instead, carboxylation or another form of activation may serve as the first step in naphthalene degradation. Degradation of toluene and 2-methylnaphthalene, and the presence of at least one bss-like and bbs

  9. Genome sequence of Phaeobacter daeponensis type strain (DSM 23529(T)), a facultatively anaerobic bacterium isolated from marine sediment, and emendation of Phaeobacter daeponensis.

    PubMed

    Dogs, Marco; Teshima, Hazuki; Petersen, Jörn; Fiebig, Anne; Chertkov, Olga; Dalingault, Hajnalka; Chen, Amy; Pati, Amrita; Goodwin, Lynne A; Chain, Patrick; Detter, John C; Ivanova, Natalia; Lapidus, Alla; Rohde, Manfred; Gronow, Sabine; Kyrpides, Nikos C; Woyke, Tanja; Simon, Meinhard; Göker, Markus; Klenk, Hans-Peter; Brinkhoff, Thorsten

    2013-10-16

    TF-218(T) is the type strain of the species Phaeobacter daeponensis Yoon et al. 2007, a facultatively anaerobic Phaeobacter species isolated from tidal flats. Here we describe the draft genome sequence and annotation of this bacterium together with previously unreported aspects of its phenotype. We analyzed the genome for genes involved in secondary metabolite production and its anaerobic lifestyle, which have also been described for its closest relative Phaeobacter caeruleus. The 4,642,596 bp long genome of strain TF-218(T) contains 4,310 protein-coding genes and 78 RNA genes including four rRNA operons and consists of five replicons: one chromosome and four extrachromosomal elements with sizes of 276 kb, 174 kb, 117 kb and 90 kb. Genome analysis showed that TF-218(T) possesses all of the genes for indigoidine biosynthesis, and on specific media the strain showed a blue pigmentation. We also found genes for dissimilatory nitrate reduction, gene-transfer agents, NRPS/ PKS genes and signaling systems homologous to the LuxR/I system.

  10. Genome sequence of Phaeobacter daeponensis type strain (DSM 23529T), a facultatively anaerobic bacterium isolated from marine sediment, and emendation of Phaeobacter daeponensis

    PubMed Central

    Dogs, Marco; Teshima, Hazuki; Petersen, Jörn; Fiebig, Anne; Chertkov, Olga; Dalingault, Hajnalka; Chen, Amy; Pati, Amrita; Goodwin, Lynne A.; Chain, Patrick; Detter, John C.; Ivanova, Natalia; Lapidus, Alla; Rohde, Manfred; Gronow, Sabine; Kyrpides, Nikos C.; Woyke, Tanja; Simon, Meinhard; Göker, Markus; Klenk, Hans-Peter; Brinkhoff, Thorsten

    2013-01-01

    TF-218T is the type strain of the species Phaeobacter daeponensis Yoon et al. 2007, a facultatively anaerobic Phaeobacter species isolated from tidal flats. Here we describe the draft genome sequence and annotation of this bacterium together with previously unreported aspects of its phenotype. We analyzed the genome for genes involved in secondary metabolite production and its anaerobic lifestyle, which have also been described for its closest relative Phaeobacter caeruleus. The 4,642,596 bp long genome of strain TF-218T contains 4,310 protein-coding genes and 78 RNA genes including four rRNA operons and consists of five replicons: one chromosome and four extrachromosomal elements with sizes of 276 kb, 174 kb, 117 kb and 90 kb. Genome analysis showed that TF-218T possesses all of the genes for indigoidine biosynthesis, and on specific media the strain showed a blue pigmentation. We also found genes for dissimilatory nitrate reduction, gene-transfer agents, NRPS/ PKS genes and signaling systems homologous to the LuxR/I system. PMID:24501652

  11. Effects of internal recycling time mode and hydraulic retention time on biological nitrogen and phosphorus removal in a sequencing anoxic/anaerobic membrane bioreactor process.

    PubMed

    Song, Kyung-Guen; Cho, Jinwoo; Ahn, Kyu-Hong

    2009-01-01

    This study investigated the effects of internal recycling time mode and hydraulic retention time (HRT) on nutrient removal in the sequencing anoxic/anaerobic membrane bioreactor process. Denitrification and phosphorus release were reciprocally dependent on the anoxic/anaerobic time ratio (Ax/An). As Ax/An increased, nitrogen removal rate increased but phosphorus removal rate decreased. The increasing Ax/An provided the longer denitrification period so that the organic substrate were consumed more for denitrification rather than phosphorus release in the limited condition of readily biodegradable substrate. Decreasing HRT increased both nitrogen and phosphorus removal efficiency because as HRT decreased, food-to-microorganism loading ratio increased and thus enhanced the biological capacity and activity of denitrifying bacteria. This could be verified from the observation mixed liquor suspended solids concentration and specific denitrification rate. The change of Ax/An and HRT affected phosphorus removal more than nitrogen removal due to the limitation of favourable carbon source for phosphorus accumulating organisms.

  12. Biochemical reaction engineering and process development in anaerobic wastewater treatment.

    PubMed

    Aivasidis, Alexander; Diamantis, Vasileios

    2005-01-01

    Developments in production technology have frequently resulted in the concentrated local accumulation of highly organic-laden wastewaters. Anaerobic wastewater treatment, in industrial applications, constitutes an advanced method of synthesis by which inexpensive substrates are converted into valuable disproportionate products. A critical discussion of certain fundamental principles of biochemical reaction engineering relevant to the anaerobic mode of operation is made here, with special emphasis on the roles of thermodynamics, kinetics, mass and heat transfer, reactor design, biomass retention and recycling. The applications of the anaerobic processes are discussed, introducing the principles of an upflow anaerobic sludge bed reactor and a fixed-bed loop reactor. The merits of staging reactor systems are presented using selected examples based on two decades of research in the field of anaerobic fermentation and wastewater treatment at the Forschungszentrum Julich (Julich Research Center, Germany). Wastewater treatment is an industrial process associated with one of the largest levels of mass throughput known, and for this reason it provides a major impetus to further developments in bioprocess technology in general.

  13. Draft Genome Sequence of Caloranaerobacter sp. TR13, an Anaerobic Thermophilic Bacterium Isolated from a Deep-Sea Hydrothermal Vent

    PubMed Central

    Xie, Yunbiao; Dong, Binbin; Liu, Qing; Chen, Xiaoyao

    2015-01-01

    Here, we report the draft 2,261,881-bp genome sequence of Caloranaerobacter sp. TR13, isolated from a deep-sea hydrothermal vent on the East Pacific Rise. The sequence will be helpful for understanding the genetic and metabolic features, as well as potential biotechnological application in the genus Caloranaerobacter. PMID:26679595

  14. Development of an energy-saving anaerobic hybrid membrane bioreactors for 2-chlorophenol-contained wastewater treatment.

    PubMed

    Wang, Yun-Kun; Pan, Xin-Rong; Sheng, Guo-Ping; Li, Wen-Wei; Shi, Bing-Jing; Yu, Han-Qing

    2015-12-01

    A novel energy-saving anaerobic hybrid membrane bioreactor (AnHMBR) with mesh filter, which takes advantage of anaerobic membrane bioreactor and fixed-bed biofilm reactor, is developed for low-strength 2-chlorophenol (2-CP)-contained wastewater treatment. In this system, the anaerobic membrane bioreactor is stuffed with granular activated carbon to construct an anaerobic hybrid fixed-bed biofilm membrane bioreactor. The effluent turbidity from the AnHMBR system was low during most of the operation period, and the chemical oxygen demand and 2-CP removal efficiencies averaged 82.3% and 92.6%, respectively. Furthermore, a low membrane fouling rate was achieved during the operation. During the AnHMBR operation, the only energy consumption was for feed pump. And a low energy demand of 0.0045-0.0063kWhm(-3) was estimated under the current operation conditions. All these results demonstrated that this novel AnHMBR is a sustainable technology for treating 2-CP-contained wastewater. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Anaerobic Infections

    MedlinePlus

    ... doses of antibiotics taken by mouth for months. Bacteroides and Prevotella infections. Bacterial organisms from species called Bacteroides and Prevotella are anaerobic. They are common organisms ...

  16. Complete Genomic Sequence of “Thermofilum adornatus” Strain 1910bT, a Hyperthermophilic Anaerobic Organotrophic Crenarchaeon

    PubMed Central

    Dominova, I. N.; Kublanov, I. V.; Podosokorskaya, O. A.; Derbikova, K. S.; Patrushev, M. V.

    2013-01-01

    The complete genomic sequence of a novel hyperthermophilic crenarchaeon, strain 1910bT, was determined. The genome comprises a 1,750,259-bp circular chromosome containing single copies of 3 rRNA genes, 43 tRNA genes, and 1,896 protein-coding sequences. In silico genome-genome hybridization suggests the proposal of a novel species, “Thermofilum adornatus” strain 1910bT. PMID:24029764

  17. Diversity of anaerobic gut fungal populations analysed using ribosomal ITS1 sequences in faeces of wild and domesticated herbivores.

    PubMed

    Nicholson, Matthew J; McSweeney, Christopher S; Mackie, Roderick I; Brookman, Jayne L; Theodorou, Michael K

    2010-04-01

    Gut fungal-specific PCR primers have been used to selectively amplify the ITS1 region of gut fungal rDNA recovered from faeces of domestic and wild animals to investigate population diversity. Two different gel-based methods are described for separating populations of gut fungal rDNA amplicons, namely (1) denaturing gradient gel electrophoresis (DGGE) and (2) separation according to small size differences using Spreadex, a proprietary matrix for electrophoresis. Gut fungal populations were characterised by analysis of rDNA in faeces of seventeen domesticated and ten wild herbivores. Sequences derived from these gel-based characterisations were analysed and classified using a hidden Markov model-based fingerprint matching algorithm. Faecal samples contained a broad spectrum of fungi and sequences from five of the six recognised genera were identified, including Cyllamyces, the most recently described gut fungal genus, which was found to be widely distributed in the samples. Furthermore, four other novel groupings of gut fungal sequences were identified that did not cluster with sequences from any of the previously described genera. Both gel- and sequence- based profiles for gut fungal populations suggested a lack of geographical restriction on occurrence of any individual fungal type.

  18. Complete Genome Sequence of Methanoregula formicica SMSPT, a Mesophilic Hydrogenotrophic Methanogen Isolated from a Methanogenic Upflow Anaerobic Sludge Blanket Reactor.

    PubMed

    Yamamoto, Kyosuke; Tamaki, Hideyuki; Cadillo-Quiroz, Hinsby; Imachi, Hiroyuki; Kyrpides, Nikos; Woyke, Tanja; Goodwin, Lynne; Zinder, Stephen H; Kamagata, Yoichi; Liu, Wen-Tso

    2014-09-04

    Methanoregula formicica SMSP(T) is a mesophilic H2/formate-utilizing methanogenic archaeon and a representative of the family Methanoregulaceae, a recently proposed novel family within the order Methanomicrobiales. Here, we report a 2.8-Mb complete genome sequence of this methanogenic archaeon.

  19. Molecular microbial diversity of an anaerobic digestor as determined by small-subunit rDNA sequence analysis.

    PubMed Central

    Godon, J J; Zumstein, E; Dabert, P; Habouzit, F; Moletta, R

    1997-01-01

    The bacterial community structure of a fluidized-bed reactor fed by vinasses (wine distillation waste) was analyzed. After PCR amplification, four small-subunit (SSU) rDNA clone libraries of Bacteria, Archaea, Procarya, and Eucarya populations were established. The community structure was determined by operational taxonomic unit (OTU) phylogenetic analyses of 579 partial rDNA sequences (about 500 bp long). A total of 146 OTUs were found, comprising 133, 6, and 7 from the Bacteria, Archaea, and Eucarya domains, respectively. A total of 117 bacterial OTU were affiliated with major phyla: low-G+C gram-positive bacteria, Cytophaga-Flexibacter-Bacteroides, Proteobacteria, high-G+C gram-positive bacteria, and Spirochaetes, where the clone distribution was 34, 26, 17, 6, and 4%, respectively. The other 16 bacterial OTUs represent 13% of the clones. They were either affiliated with narrow phyla such as Planctomyces-Chlamydia, green nonsulfur bacteria, or Synergistes, or deeply branched on the phylogenetic tree. A large number of bacterial OTUs are not closely related to any other hitherto determined sequences. The most frequent bacterial OTUs represents less than 5% of the total bacterial SSU rDNA sequences. However, the 20 more frequent bacterial OTUs describe at least 50% of these sequences. Three of the six Archaea OTUs correspond to 95% of the Archaea population and are very similar to already known methanogenic species: Methanosarcina barkeri, Methanosarcina frisius, and Methanobacterium formicicum. In contrast, the three other Archaea OTUs are unusual and are related to thermophilic microorganisms such as Crenarchaea or Thermoplasma spp. Five percent of the sequences analyzed were chimeras and were removed from the analysis. PMID:9212428

  20. Molecular microbial diversity of an anaerobic digestor as determined by small-subunit rDNA sequence analysis.

    PubMed

    Godon, J J; Zumstein, E; Dabert, P; Habouzit, F; Moletta, R

    1997-07-01

    The bacterial community structure of a fluidized-bed reactor fed by vinasses (wine distillation waste) was analyzed. After PCR amplification, four small-subunit (SSU) rDNA clone libraries of Bacteria, Archaea, Procarya, and Eucarya populations were established. The community structure was determined by operational taxonomic unit (OTU) phylogenetic analyses of 579 partial rDNA sequences (about 500 bp long). A total of 146 OTUs were found, comprising 133, 6, and 7 from the Bacteria, Archaea, and Eucarya domains, respectively. A total of 117 bacterial OTU were affiliated with major phyla: low-G+C gram-positive bacteria, Cytophaga-Flexibacter-Bacteroides, Proteobacteria, high-G+C gram-positive bacteria, and Spirochaetes, where the clone distribution was 34, 26, 17, 6, and 4%, respectively. The other 16 bacterial OTUs represent 13% of the clones. They were either affiliated with narrow phyla such as Planctomyces-Chlamydia, green nonsulfur bacteria, or Synergistes, or deeply branched on the phylogenetic tree. A large number of bacterial OTUs are not closely related to any other hitherto determined sequences. The most frequent bacterial OTUs represents less than 5% of the total bacterial SSU rDNA sequences. However, the 20 more frequent bacterial OTUs describe at least 50% of these sequences. Three of the six Archaea OTUs correspond to 95% of the Archaea population and are very similar to already known methanogenic species: Methanosarcina barkeri, Methanosarcina frisius, and Methanobacterium formicicum. In contrast, the three other Archaea OTUs are unusual and are related to thermophilic microorganisms such as Crenarchaea or Thermoplasma spp. Five percent of the sequences analyzed were chimeras and were removed from the analysis.

  1. Sequence and Genetic Characterization of etrA, an fnr Analog that Regulates Anaerobic Respiration in Shewanella putrefaciens MR-1

    NASA Technical Reports Server (NTRS)

    Saffarini, Daad A.; Nelson, Kenneth H.

    1993-01-01

    An electron transport regulatory gene, etrA, has been isolated and characterized from the obligate respiratory bacterium Shewanella putrefaciens MR-l. The deduced amino acid sequence of etrA (EtrA) shows a high degree of identity to both the Fnr of Escherichia coli (73.6%) and the analogous protein (ANR) of Pseudomonas aeruginosa (50.8%). The four active cysteine residues of Fnr are conserved in EtrA, and the amino acid sequence of the DNA-binding domains of the two proteins are identical. Further, S.putrefaciens etrA is able to complement an fnr mutant of E.coli. In contrast to fnr, there is no recognizable Fnr box upstream of the etrA sequence. Gene replacement etr.A mutants of MR-1 were deficient in growth on nitrite, thiosulfate, sulfite, trimethylamine-N-oxide, dimethyl sulfoxide, Fe(III), and fumarate, suggesting that EtrA is involved in the regulation of the corresponding reductase genes. However, the mutants were all positive for reduction of and growth on nitrate and Mn(IV), indicating that EtrA is not involved in the regulation of these two systems. Southern blots of S.putrefaciens DNA with use of etrA as a probe revealed the expected etrA bands and a second set of hybridization signals whose genetic and functional properties remain to be determined.

  2. Sequence and Genetic Characterization of etrA, an fnr Analog that Regulates Anaerobic Respiration in Shewanella putrefaciens MR-1

    NASA Technical Reports Server (NTRS)

    Saffarini, Daad A.; Nelson, Kenneth H.

    1993-01-01

    An electron transport regulatory gene, etrA, has been isolated and characterized from the obligate respiratory bacterium Shewanella putrefaciens MR-l. The deduced amino acid sequence of etrA (EtrA) shows a high degree of identity to both the Fnr of Escherichia coli (73.6%) and the analogous protein (ANR) of Pseudomonas aeruginosa (50.8%). The four active cysteine residues of Fnr are conserved in EtrA, and the amino acid sequence of the DNA-binding domains of the two proteins are identical. Further, S.putrefaciens etrA is able to complement an fnr mutant of E.coli. In contrast to fnr, there is no recognizable Fnr box upstream of the etrA sequence. Gene replacement etr.A mutants of MR-1 were deficient in growth on nitrite, thiosulfate, sulfite, trimethylamine-N-oxide, dimethyl sulfoxide, Fe(III), and fumarate, suggesting that EtrA is involved in the regulation of the corresponding reductase genes. However, the mutants were all positive for reduction of and growth on nitrate and Mn(IV), indicating that EtrA is not involved in the regulation of these two systems. Southern blots of S.putrefaciens DNA with use of etrA as a probe revealed the expected etrA bands and a second set of hybridization signals whose genetic and functional properties remain to be determined.

  3. Evaluation of Anaerobic Biofilm Reactor Kinetic Parameters Using Ant Colony Optimization.

    PubMed

    Satya, Eswari Jujjavarapu; Venkateswarlu, Chimmiri

    2013-09-01

    Fixed bed reactors with naturally attached biofilms are increasingly used for anaerobic treatment of industry wastewaters due their effective treatment performance. The complex nature of biological reactions in biofilm processes often poses difficulty in analyzing them experimentally, and mathematical models could be very useful for their design and analysis. However, effective application of biofilm reactor models to practical problems suffers due to the lack of knowledge of accurate kinetic models and uncertainty in model parameters. In this work, an inverse modeling approach based on ant colony optimization is proposed and applied to estimate the kinetic and film thickness model parameters of wastewater treatment process in an anaerobic fixed bed biofilm reactor. Experimental data of pharmaceutical industry wastewater treatment process are used to determine the model parameters as a consequence of the solution of the rigorous mathematical models of the process. Results were evaluated for different modeling configurations derived from the combination of mathematical models, kinetic expressions, and optimization algorithms. Analysis of results showed that the two-dimensional mathematical model with Haldane kinetics better represents the pharmaceutical wastewater treatment in the biofilm reactor. The mathematical and kinetic modeling of this work forms a useful basis for the design and optimization of industry wastewater treating biofilm reactors.

  4. Evaluation of Anaerobic Biofilm Reactor Kinetic Parameters Using Ant Colony Optimization

    PubMed Central

    Satya, Eswari Jujjavarapu; Venkateswarlu, Chimmiri

    2013-01-01

    Abstract Fixed bed reactors with naturally attached biofilms are increasingly used for anaerobic treatment of industry wastewaters due their effective treatment performance. The complex nature of biological reactions in biofilm processes often poses difficulty in analyzing them experimentally, and mathematical models could be very useful for their design and analysis. However, effective application of biofilm reactor models to practical problems suffers due to the lack of knowledge of accurate kinetic models and uncertainty in model parameters. In this work, an inverse modeling approach based on ant colony optimization is proposed and applied to estimate the kinetic and film thickness model parameters of wastewater treatment process in an anaerobic fixed bed biofilm reactor. Experimental data of pharmaceutical industry wastewater treatment process are used to determine the model parameters as a consequence of the solution of the rigorous mathematical models of the process. Results were evaluated for different modeling configurations derived from the combination of mathematical models, kinetic expressions, and optimization algorithms. Analysis of results showed that the two-dimensional mathematical model with Haldane kinetics better represents the pharmaceutical wastewater treatment in the biofilm reactor. The mathematical and kinetic modeling of this work forms a useful basis for the design and optimization of industry wastewater treating biofilm reactors. PMID:24065871

  5. Treatment of distillery vinasse in a high rate anaerobic reactor using low density polyethylene supports.

    PubMed

    Thanikal, J V; Torrijos, M; Habouzit, F; Moletta, R

    2007-01-01

    An anaerobic fixed bed reactor, filled with small floating supports of polyethylene material (Bioflow 30) as inert media, was operated for 6 months to treat vinasse (wine residue after distillation). Bioflow 30 has a density of 0.93 and a specific area of 320 m2/m3. The experimental results showed that the efficiency of the reactor in removal of soluble COD was very good with a maximum organic loading rate of more than 30 g of COD/L x d and a COD removal efficiency of more than 80%. Bioflow 30 showed a high capability of biomass retention with 4-6 g of dried solids per support. Thus, at the end of the experiment, the fixed biomass represented 57 g of solids/L of reactor. The visual observation of the supports and the specific activity (0.54 g COD/g solids x d) of the fixed solids, which remained close to the values obtained with suspended biomass, showed that entrapment was playing an important role in the retention of the biomass inside the reactor. It was then possible to operate the reactor with a very high loading rate as the result of the increase of the solids in the reactor and the maintaining of the specific activity. Bioflow 30 is then an excellent support for use in a high rate anaerobic fixed bed.

  6. Biogenic Hydrogen Conversion of De-Oiled Jatropha Waste via Anaerobic Sequencing Batch Reactor Operation: Process Performance, Microbial Insights, and CO2 Reduction Efficiency

    PubMed Central

    Lin, Chiu-Yue

    2014-01-01

    We report the semicontinuous, direct (anaerobic sequencing batch reactor operation) hydrogen fermentation of de-oiled jatropha waste (DJW). The effect of hydraulic retention time (HRT) was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L∗d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d) with a DJW concentration of 200 g/L, temperature 55°C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L∗d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30°C, and pH 7.0. PCR-DGGE analysis revealed that combination of celluloytic and fermentative bacteria were present in the hydrogen producing ASBR. PMID:24672398

  7. Integration of a Coagulation/Flocculation step in a biological sequencing batch reactor for COD and nitrogen removal of supernatant of anaerobically digested piggery wastewater.

    PubMed

    Dosta, J; Rovira, J; Galí, A; Macé, S; Mata-Alvarez, J

    2008-09-01

    The supernatant from mesophilic anaerobic digestion of piggery wastewater is characterised by a high amount of COD (4.1 g COD L(-1)), ammonium (2.3g NH(4)(+)-NL(-1)) and suspended solids (2.5 g SS L(-1)). This effluent can be efficiently treated by means of a Sequencing Batch Reactor (SBR) strategy for biological COD, SS and nitrogen removal including a Coagulation/Flocculation step. Total COD and SS reduction yields higher than 66% and 74%, respectively, and a total nitrogen removal (via nitrite) of more than 98% were reached when working with HRT 2.7 days, SRT 12 days, temperature 32 degrees C, three aerobic/anoxic periods, without external control of pH and under limited aeration flow. The inhibition of nitrite oxidizing biomass was achieved by the working free ammonia concentration and the restricted air supply (dissolved oxygen concentration below 1 mg O(2)L(-1)). Since a part of the total COD was colloidal and/or refractory, a Coagulation/Flocculation step was implemented inside the SBR operating strategy to meet a suitable effluent quality to be discharged. Several Jar-Tests demonstrated that the optimal concentration of FeCl(3) was 800 mg L(-1). A respirometric assay showed that this coagulant dosage did not affect the biological activity of nitrifying/denitrifying biomass.

  8. Establishment of thermophilic anaerobic terephthalic acid degradation system through one-step temperature increase startup strategy - Revealed by Illumina Miseq Sequencing.

    PubMed

    Ma, Kai-Li; Li, Xiang-Kun; Wang, Ke; Meng, Ling-Wei; Liu, Gai-Ge; Zhang, Jie

    2017-10-01

    Over recent years, thermophilic digestion was constantly focused owing to its various advantage over mesophilic digestion. Notably, the startup approach of thermophilic digester needs to be seriously considered as unsuitable startup ways may result in system inefficiency. In this study, one-step temperature increase startup strategy from 37 °C to 55 °C was applied to establish a thermophilic anaerobic system treating terephthalic acid (TA) contained wastewater, meanwhile, the archaeal and bacterial community compositions at steady periods of 37 °C and 55 °C during the experimental process was also compared using Illumina Miseq Sequencing. The process operation demonstrated that the thermophilic TA degradation system was successfully established at 55 °C with over 95% COD reduction. For archaea community, the elevation of operational temperature from 37 °C to 55 °C accordingly increase the enrichment of hydrogenotrophic methanogens but decrease the abundance of the acetotrophic ones. While for bacterial community, the taxonomic analysis suggested that Syntrophorhabdus (27.40%) was the dominant genus promoting the efficient TA degradation under mesophilic condition, whereas OPB95 (24.99%) and TA06 (14.01%) related populations were largely observed and probably take some crucial role in TA degradation under thermophilic condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Biogenic hydrogen conversion of de-oiled jatropha waste via anaerobic sequencing batch reactor operation: process performance, microbial insights, and CO2 reduction efficiency.

    PubMed

    Kumar, Gopalakrishnan; Lin, Chiu-Yue

    2014-01-01

    We report the semicontinuous, direct (anaerobic sequencing batch reactor operation) hydrogen fermentation of de-oiled jatropha waste (DJW). The effect of hydraulic retention time (HRT) was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L ∗ d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d) with a DJW concentration of 200 g/L, temperature 55 °C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L ∗ d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30 °C, and pH 7.0. PCR-DGGE analysis revealed that combination of cellulolytic and fermentative bacteria were present in the hydrogen producing ASBR.

  10. The first metagenome of activated sludge from full-scale anaerobic/anoxic/oxic (A2O) nitrogen and phosphorus removal reactor using Illumina sequencing.

    PubMed

    Tian, Mei; Zhao, Fangqing; Shen, Xin; Chu, Kahou; Wang, Jinfeng; Chen, Shuai; Guo, Yan; Liu, Hanhu

    2015-09-01

    The anaerobic/anoxic/oxic (A2O) process is globally one of the widely used biological sewage treatment processes. This is the first report of a metagenomic analysis using Illumina sequencing of full-scale A2O sludge from a municipal sewage treatment plant. With more than 530,000 clean reads from different taxa and metabolic categories, the metagenome results allow us to gain insight into the functioning of the biological community of the A2O sludge. There are 51 phyla and nearly 900 genera identified from the A2O activated sludge ecosystem. Proteobacteria, Bacteroidetes, Nitrospirae and Chloroflexi are predominant phyla in the activated sludge, suggesting that these organisms play key roles in the biodegradation processes in the A2O sewage treatment system. Nitrospira, Thauera, Dechloromonas and Ignavibacterium, which have abilities to metabolize nitrogen and aromatic compounds, are most prevalent genera. The percent of nitrogen and phosphorus metabolism in the A2O sludge is 2.72% and 1.48%, respectively. In the current A2O sludge, the proportion of Candidatus Accumulibacter is 1.37%, which is several times more than that reported in a recent study of A2O sludge. Among the four processes of nitrogen metabolism, denitrification related genes had the highest number of sequences (76.74%), followed by ammonification (15.77%), nitrogen fixation (3.88%) and nitrification (3.61%). In phylum Planctomycetes, four genera (Planctomyces, Pirellula, Gemmata and Singulisphaera) are included in the top 30 abundant genera, suggesting the key role of ANAMMOX in nitrogen metabolism in the A2O sludge.

  11. Treatment of fruit-juice industry wastewater in a two-stage anaerobic hybrid (AH) reactor system followed by a sequencing batch reactor (SBR).

    PubMed

    Tawfik, A; El-Kamah, H

    2012-01-01

    This study has been carried out to assess the performance of a combined system consisting of an anaerobic hybrid (AH) reactor followed by a sequencing batch reactor (SBR) for treatment of fruit-juice industry wastewater at a temperature of 26 degrees C. Three experimental runs were conducted in this investigation. In the first experiment, a single-stage AH reactor was operated at a hydraulic retention time (HRT) of 10.2 h and organic loading rate (OLR) of 11.8 kg COD m(-3) d(-1). The reactor achieved a removal efficiency of 42% for chemical oxygen demand (COD), 50.8% for biochemical oxygen demand (BOD5), 50.3% for volatile fatty acids (VFA) and 56.4% for total suspended solids (TSS). In the second experiment, two AH reactors connected in series achieved a higher removal efficiency for COD (67.4%), BOD5 (77%), and TSS (71.5%) at a total HRT of 20 h and an OLR of 5.9 kg COD m(-3) d(-1). For removal of the remaining portions of COD, BOD5 and TSS from the effluent of the two-stage AH system, a sequencing batch reactor (SBR) was investigated as a post-treatment unit. The reactor achieved a substantial reduction in total COD, resulting in an average effluent concentration of 50 mg L(-1) at an HRT of 11 h and OLR of 5.3 kg COD m(-3) d(-1). Almost complete removal of total BOD5 and oil and grease was achieved, i.e. 10 mg L(-1) and 1.2 mg L(-1), respectively, remained in the final effluent of the SBR.

  12. Isolation and characterization of Desulfocurvus thunnarius sp. nov., a sulfate-reducing bacterium isolated from an anaerobic sequencing batch reactor treating cooking wastewater.

    PubMed

    Hamdi, Olfa; Ben Hania, Wajdi; Postec, Anne; Bartoli, Manon; Hamdi, Moktar; Bouallagui, Hassib; Fauque, Guy; Ollivier, Bernard; Fardeau, Marie-Laure

    2013-11-01

    A novel anaerobic, chemo-organotrophic, sulfate-reducing bacterium, designated strain Olac 40(T), was isolated from a Tunisian wastewater digestor. Cells were curved, motile rods or vibrios (5.0-7.0×0.5 µm). Strain Olac 40(T) grew at temperatures between 15 and 50 °C (optimum 40 °C), and between pH 5.0 and 9.0 (optimum pH 7.1). It did not require NaCl for growth but tolerated it up to 50 g l(-1) (optimum 2 g l(-1)). In the presence of sulfate or thiosulfate, strain Olac 40(T) used lactate, pyruvate and formate as energy sources. Growth was observed on H2 only in the presence of acetate as carbon source. In the presence of sulfate or thiosulfate, the end products of lactate oxidation were acetate, sulfide and CO2. Sulfate, thiosulfate and sulfite were used as terminal electron acceptors, but not elemental sulfur, nitrate or nitrite. The genomic DNA G+C content of strain Olac 40(T) was 70 mol%. The profile of polar lipids consisted of phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and four phospholipids. The main fatty acids were C16 : 0, anteiso-C15 : 0 and iso-C15 : 0. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain Olac 40(T) was affiliated with the family Desulfovibrionaceae within the class Deltaproteobacteria. On the basis of 16S rRNA gene sequence comparisons and physiological characteristics, strain Olac 40(T) is proposed to be assigned to a novel species of the genus Desulfocurvus, for which the name Desulfocurvus thunnarius is proposed. The type strain is Olac 40(T) ( = DSM 26129(T) = JCM 18546(T)).

  13. Whole-Genome Sequence of the Anaerobic Isosaccharinic Acid Degrading Isolate, Macellibacteroides fermentans Strain HH-ZS.

    PubMed

    Rout, Simon P; Salah, Zohier B; Charles, Christopher J; Humphreys, Paul N

    2017-08-01

    The ability of micro-organisms to degrade isosaccharinic acids (ISAs) while tolerating hyperalkaline conditions is pivotal to our understanding of the biogeochemistry associated within these environs, but also in scenarios pertaining to the cementitious disposal of radioactive wastes. An alkalitolerant, ISA degrading micro-organism was isolated from the hyperalkaline soils resulting from lime depositions. Here, we report the first whole-genome sequence, ISA degradation profile and carbohydrate preoteome of a Macellibacteroides fermentans strain HH-ZS, 4.08 Mb in size, coding 3,241 proteins, 64 tRNA, and 1 rRNA. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  14. Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor

    PubMed Central

    Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

    2015-01-01

    Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3−-N could be removed or reduced, some amount of NO2−-N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy. PMID:26257096

  15. Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor.

    PubMed

    Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

    2015-08-10

    Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3(-)-N could be removed or reduced, some amount of NO2(-)-N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy.

  16. Microbial fuel cell based biosensor for in situ monitoring of anaerobic digestion process.

    PubMed

    Liu, Zhidan; Liu, Jing; Zhang, Songping; Xing, Xin-Hui; Su, Zhiguo

    2011-11-01

    A wall-jet microbial fuel cell (MFC) was developed for the monitoring of anaerobic digestion (AD). This biofilm based MFC biosensor had a character of being portable, short hydraulic retention time (HRT) for sample flow through and convenient for continuous operation. The MFC was installed in the recirculation loop of an upflow anaerobic fixed-bed (UAFB) reactor in bench-scale where pH of the fermentation broth and biogas flow were monitored in real time. External disturbances to the AD were added on purpose by changing feedstock concentration, as well as process configuration. MFC signals had good correlations with online measurements (i.e. pH, gas flow rate) and offline analysis (i.e. COD) over 6-month operation. These results suggest that the MFC signal can reflect the dynamic variation of AD and can potentially be a valuable tool for monitoring and control of bioprocess. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Characterization study and five-cycle tests in a fixed-bed reactor of titania-supported nickel oxide as oxygen carriers for the chemical-looping combustion of methane.

    PubMed

    Corbella, Beatriz M; de Diego, Luis F; García-Labiano, Francisco; Adánez, Juan; Palaciost, José M

    2005-08-01

    Recent investigations have shown that in the combustion of carbonaceous compounds CO2 and NOx emissions to the atmosphere can be substantially reduced by using a two stage chemical-looping process. In this process, the reduction stage is undertaken in a first reactor in which the framework oxygen of a reducible inorganic oxide is used, instead of the usual atmospheric oxygen, for the combustion of a carbonaceous compound, for instance, methane. The outlet gas from this reactor is mostly composed of CO2 and steam as reaction products and further separation of these two components can be carried out easily by simple condensation of steam. Then, the oxygen carrier found in a reduced state is transported to a second reactor in which carrier regeneration with air takes place at relatively low temperatures, consequently preventing the formation of thermal NOx. Afterward, the regenerated carrier is carried to the first reactor to reinitiate a new cycle and so on for a number of repetitive cycles, while the carrier is able to withstand the severe chemical and thermal stresses involved in every cycle. In this paper, the performance of titania-supported nickel oxides has been investigated in a fixed-bed reactor as oxygen carriers for chemical-looping combustion of methane. Samples with different nickel oxide contents were prepared by successive incipient wet impregnations, and their performance as oxygen carriers was investigated at 900 degrees C and atmospheric pressure in five-cycle fixed-bed reactor tests using pure methane and pure air for the respective reduction and regeneration stages. The evolution of the outlet gas composition in each stage was followed by gas chromatography, and the involved chemical, structural, and textural changes of the carrier in the reactor bed were studied by using different characterization techniques. From the study, it is deduced that the reactivity of these nickel-based oxygen carriers is in the two involved stages and almost independent

  18. The Genome Sequences of Cellulomonas fimi and “Cellvibrio gilvus” Reveal the Cellulolytic Strategies of Two Facultative Anaerobes, Transfer of “Cellvibrio gilvus” to the Genus Cellulomonas, and Proposal of Cellulomonas gilvus sp. nov

    PubMed Central

    Bramhacharya, Shanti; Jewell, Kelsea A.; Aylward, Frank O.; Mead, David; Brumm, Phillip J.

    2013-01-01

    Actinobacteria in the genus Cellulomonas are the only known and reported cellulolytic facultative anaerobes. To better understand the cellulolytic strategy employed by these bacteria, we sequenced the genome of the Cellulomonas fimi ATCC 484T. For comparative purposes, we also sequenced the genome of the aerobic cellulolytic “Cellvibrio gilvus” ATCC 13127T. An initial analysis of these genomes using phylogenetic and whole-genome comparison revealed that “Cellvibrio gilvus” belongs to the genus Cellulomonas. We thus propose to assign “Cellvibrio gilvus” to the genus Cellulomonas. A comparative genomics analysis between these two Cellulomonas genome sequences and the recently completed genome for Cellulomonas flavigena ATCC 482T showed that these cellulomonads do not encode cellulosomes but appear to degrade cellulose by secreting multi-domain glycoside hydrolases. Despite the minimal number of carbohydrate-active enzymes encoded by these genomes, as compared to other known cellulolytic organisms, these bacteria were found to be proficient at degrading and utilizing a diverse set of carbohydrates, including crystalline cellulose. Moreover, they also encode for proteins required for the fermentation of hexose and xylose sugars into products such as ethanol. Finally, we found relatively few significant differences between the predicted carbohydrate-active enzymes encoded by these Cellulomonas genomes, in contrast to previous studies reporting differences in physiological approaches for carbohydrate degradation. Our sequencing and analysis of these genomes sheds light onto the mechanism through which these facultative anaerobes degrade cellulose, suggesting that the sequenced cellulomonads use secreted, multidomain enzymes to degrade cellulose in a way that is distinct from known anaerobic cellulolytic strategies. PMID:23342046

  19. Growth of single-walled carbon nanotubes on a Co-Mo-MgO supported catalyst by the CVD of methane in a fixed bed reactor: Model setting and parameter estimation

    NASA Astrophysics Data System (ADS)

    Izadi, Nosrat; Rashidi, Ali Morad; Horri, Bahman Amini; Mosoudi, Mohamad Reza; Bozorgzadeh, Hamid Reza; Zeraatkar, Ahmad

    2011-06-01

    In this work methane was decomposed to hydrogen and carbon to determine its kinetic behavior during reaction over a Co-Mo-MgO supported catalyst using the CVD (Chemical Vapor Deposition) technique. Decomposition of methane molecules was performed in a continuous fixed bed reactor to obtain data to simulate methane decomposition in a gas phase heterogeneous media. The products and reactants of reaction were analyzed by molecular sieve column followed by GC-analysis of the fractions to determine the amount of product converted or reactant consumed. The synthesis of single-walled carbon nanotubes was performed at atmospheric pressure, different temperatures and reactant concentrations. The experimental data analyzed to suggest the formula for calculation of the initial specific reaction rate of the carbon nanotubes synthesis, were fitted by several mathematical models derived from different mechanisms based on Longmuir-hinshelwood expression. The suggested mechanism according to dissociation adsorption of methane seems to explain the catalytic performance in the range of operating conditions studied. The apparent activation energy for the growth of SWNTs was estimated according to Arrhenius equation. The as grown SWNTs products were characterized by SEM, TEM and Raman spectroscopy after purification. The catalyst deactivation was found to be dependent on the time, reaction temperature and partial pressure of methane and indicated that the reaction of deactivation can be modeled by a simple apparent second order of reaction.

  20. Kinetics, mass transfer and hydrodynamics in a packed bed aerobic reactor fed with anaerobically treated domestic sewage.

    PubMed

    Fazolo, A; Pasotto, M B; Foresti, E; Zaiat, M

    2006-10-01

    This study presents an assessment of the kinetic, mass transfer and hydrodynamic parameters of a pilot-scale fixed bed reactor containing immobilized biomass in polyurethane matrices and fed with the effluent of a horizontal-flow fixed bed anaerobic reactor, which was used to treat domestic sewage. It was found that the liquid-solid and intra-particle mass transfer resistances significantly affected the overall oxygen consumption rate and that mechanical agitation could minimize such resistances. The volumetric oxygen transfer coefficient (kLa) values for superficial air velocities between 8.4 cm min(-1) and 57.0 cm min(-1) varied from 20.8 h(-1) to 58.8 h(-1) for tap water, and 16.8 h(-1) to 53.0 h(-1) for the anaerobic pre-treated effluent. The intrinsic oxygen uptake rate was estimated to be 19.9 mgO2 gVSS(-1) h(-1). A first-order kinetic model with residual concentration was considered to adequately represent the COD removal rate, whereas nitrogen conversion was considered to be well represented by a model of pseudo-first-order reaction in series. It was also found that the ammonium conversion to nitrite was the limiting step of the overall nitrogen conversion rate. The hydrodynamic behavior of the reactor was represented by three to four completely mixed reactors in series.

  1. Process for fixed bed coal gasification

    DOEpatents

    Sadowski, Richard S.

    1992-01-01

    The combustion of gas produced from the combination of coal pyrolysis and gasification involves combining a combustible gas coal and an oxidant in a pyrolysis chamber and heating the components to a temperature of at least 1600.degree. F. The products of coal pyrolysis are dispersed from the pyrolyzer directly into the high temperature gasification region of a pressure vessel. Steam and air needed for gasification are introduced in the pressure vessel and the materials exiting the pyrolyzer flow down through the pressure vessel by gravity with sufficient residence time to allow any carbon to form carbon monoxide. Gas produced from these reactions are then released from the pressure vessel and ash is disposed of.

  2. Application of real-time PCR to determination of combined effect of antibiotics on Bacteria, Methanogenic Archaea, Archaea in anaerobic sequencing batch reactors.

    PubMed

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2015-06-01

    This study evaluated the long-term effects of erythromycin-tetracycline-sulfamethoxazole (ETS) and sulfamethoxazole-tetracycline (ST) antibiotic combinations on the microbial community and examined the ways in which these antimicrobials impact the performance of anaerobic reactors. Quantitative real-time PCR was used to determine the effect that different antibiotic combinations had on the total and active Bacteria, Archae and Methanogenic Archae. Three primer sets that targeted metabolic genes encoding formylterahydrofolate synthetase, methyl-coenzyme M reductase and acetyl-coA synthetase were also used to determine the inhibition level on the mRNA expression of the homoacetogens, methanogens and specifically acetoclastic methanogens, respectively. These microorganisms play a vital role in the anaerobic degradation of organic waste and targeting these gene expressions offers operators or someone at a treatment plant the potential to control and the improve the anaerobic system. The results of the investigation revealed that acetogens have a competitive advantage over Archaea in the presence of ETS and ST combinations. Although the efficiency with which methane production takes place and the quantification of microbial populations in both the ETS and ST reactors decreased as antibiotic concentrations increased, the ETS batch reactor performed better than the ST batch reactor. According to the expression of genes results, the syntrophic interaction of acetogens and methanogens is critical to the performance of the ETS and ST reactors. Failure to maintain the stability of these microorganisms resulted in a decrease in the performance and stability of the anaerobic reactors.

  3. Genome sequence of Victivallis vadensis ATCC BAA-548, an anaerobic bacterium from the phylum Lentisphaerae, isolated from the human gastrointestinal tract.

    PubMed

    van Passel, Mark W J; Kant, Ravi; Palva, Airi; Lucas, Susan; Copeland, Alex; Lapidus, Alla; Glavina del Rio, Tijana; Dalin, Eileen; Tice, Hope; Bruce, David; Goodwin, Lynne; Pitluck, Sam; Davenport, Karen Walston; Sims, David; Brettin, Thomas S; Detter, John C; Han, Shunsheng; Larimer, Frank W; Land, Miriam L; Hauser, Loren; Kyrpides, Nikolaos; Ovchinnikova, Galina; Richardson, P Paul; de Vos, Willem M; Smidt, Hauke; Zoetendal, Erwin G

    2011-05-01

    Victivallis vadensis ATCC BAA-548 represents the first cultured representative from the novel phylum Lentisphaerae, a deep-branching bacterial lineage. Few cultured bacteria from this phylum are known, and V. vadensis therefore represents an important organism for evolutionary studies. V. vadensis is a strictly anaerobic sugar-fermenting isolate from the human gastrointestinal tract.

  4. Genome sequence of Victivallis vadensis ATCC BAA-548, an anaerobic bacterium from the phylum Lentisphaerae, isolated from the human gastro-intestinal tract

    SciTech Connect

    Van Passel, Mark W.J.; Kant, Ravi; Palva, Airi; Lucas, Susan; Copeland, A; Lapidus, Alla L.; Glavina Del Rio, Tijana; Dalin, Eileen; Tice, Hope; Bruce, David; Goodwin, Lynne A.; Pitluck, Sam; Davenport, Karen W.; Sims, David; Detter, J. Chris; Han, Cliff; Larimer, Frank W; Land, Miriam L; Hauser, Loren John; Kyrpides, Nikos C; Ovchinnikova, Galina; Richardson, Paul; De Vos, Willem M.; Smidt, Hauke; Zoetendal, Erwin G.

    2011-01-01

    Victivallis vadensis ATCC BAA-548 represents the first cultured representative from the novel phylum Lentisphaerae, a deep-branching bacterial lineage. Few cultured bacteria from this phylum are known, and V. vadensis therefore represents an important organism for evolutionary studies. V. vadensis is a strictly anaerobic sugar-fermenting isolate from the human gastro-intestinal tract.

  5. The investigation of effect of organic carbon sources addition in anaerobic-aerobic (low dissolved oxygen) sequencing batch reactor for nutrients removal from wastewaters.

    PubMed

    Zheng, Xiong; Tong, Juan; Li, Hongjing; Chen, Yinguang

    2009-05-01

    The effect of addition of organic carbon sources (acetic acid and waste activated sludge alkaline fermentation liquid) on anaerobic-aerobic (low dissolved oxygen, 0.15-0.45 mg/L) biological municipal wastewater treatment was investigated. The results showed that carbon source addition affected not only the transformations of polyhydroxyalkanoates (PHA), glycogen, nitrogen and phosphorus, but the net removal of nitrogen and phosphorus. The removal efficiencies of TN and TP were, respectively, 61% and 61% without organic carbon source addition, 81% and 95% with acetic acid addition, and 83% and 97% with waste activated sludge alkaline fermentation liquid addition. It seems that the alkaline fermentation liquid of waste biosolids generated in biological wastewater treatment plant can be used to replace acetic acid as an additional carbon source to improve the anaerobic-aerobic (low dissolved oxygen) municipal wastewater nutrients removal although its use was observed to cause a slight increase of effluent BOD and COD concentrations.

  6. Anaerobic Digestion.

    PubMed

    Liebetrau, Jan; Sträuber, Heike; Kretzschmar, Jörg; Denysenko, Velina; Nelles, Michael

    2017-04-09

    The term anaerobic digestion usually refers to the microbial conversion of organic material to biogas, which mainly consists of methane and carbon dioxide. The technical application of the naturally-occurring process is used to provide a renewable energy carrier and - as the substrate is often waste material - to reduce the organic matter content of the substrate prior to disposal.Applications can be found in sewage sludge treatment, the treatment of industrial and municipal solid wastes and wastewaters (including landfill gas utilization), and the conversion of agricultural residues and energy crops.For biorefinery concepts, the anaerobic digestion (AD) process is, on the one hand, an option to treat organic residues from other production processes. Concomitant effects are the reduction of organic carbon within the treated substance, the conversion of nitrogen and sulfur components, and the production of an energy-rich gas - the biogas. On the other hand, the multistep conversion of complex organic material offers the possibility of interrupting the conversion chain and locking out intermediates for utilization as basic material within the chemical industry.

  7. Biological nutrient removal with low nitrous oxide generation by cancelling the anaerobic phase and extending the idle phase in a sequencing batch reactor.

    PubMed

    Chen, Yinguang; Wang, Dongbo; Zheng, Xiong; Li, Xiang; Feng, Leiyu; Chen, Hong

    2014-08-01

    Although wastewater biological nutrient removal can be achieved by alternating the anaerobic-oxic-anoxic phases, significant amount of nitrous oxide (N2O) is generated in oxic phases, where ammonia-oxidizing bacteria (AOB) rather than heterotrophic denitrifiers are the main contributors. Here a new efficient strategy to remarkably reduce N2O generation was reported. It was found that by cancelling the anaerobic phase and extending the idle phase the N2O generation was reduced by 42% using synthetic wastewater, whereas the total nitrogen and phosphorus removals were unaffected. The mechanistic investigations revealed that the cancelling of anaerobic phase benefited heterotrophic denitrifiers instead of AOB to be responsible for nitrogen removal in the oxic phases, increased the ratio of total nitrogen removal driven by external carbon source, and decreased nitrite accumulation. Quantitative real-time polymerase chain reaction and fluorescence in situ hybridization analyses further showed that the new strategy increased the number of N2O reducing bacteria but decreased the abundance of glycogen accumulating organisms, with N2O as their primary denitrification product. It was also determined that the ratio of nitric oxide reductase activity to N2O reductase activity was significantly decreased after anaerobic phase was cancelled. All these observations were in accord with the reduction of N2O production. The feasibility of this strategy to minimize the generation of N2O was finally confirmed for a real municipal wastewater. The results reported in this paper provide a new viewpoint to reduce N2O generation from wastewater biological nutrient removal.

  8. Anaerobic thermophiles.

    PubMed

    Canganella, Francesco; Wiegel, Juergen

    2014-02-26

    The term "extremophile" was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of "extreme" environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally "hot environments" on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong to the Archaea has definitely

  9. Anaerobic Thermophiles

    PubMed Central

    Canganella, Francesco; Wiegel, Juergen

    2014-01-01

    The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong to the Archaea has

  10. Carbonic anhydrases of anaerobic microbes.

    PubMed

    Ferry, James G

    2013-03-15

    Carbonic anhydrases (CAs) catalyze the reversible hydration of carbon dioxide to bicarbonate and are abundantly distributed in prokaryotes and eukaryotes. There are five classes (α,β,γ,δ,ζ) with no significant sequence or structural identity among them, a remarkable example of convergent evolution. The β and γ classes predominate in anaerobic microbes, living without O2, that comprise a substantial portion of the living protoplasm on Earth. Anaerobes reside in the lower intestinal tract of humans, one of many O2-free environments on Earth, where they convert complex biomass to methane and CO2 contributing an essential link in the global carbon cycle. Carbon dioxide is a universal metabolite of anaerobes necessitating CA for a diversity of proposed functions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Complete genome sequence of Anaeromyxobacter sp. Fw109-5, an Anaerobic, Metal-Reducing Bacterium Isolated from a Contaminated Subsurface Environment

    DOE PAGES

    Hwang, C.; Copeland, A.; Lucas, Susan; ...

    2015-01-22

    We report the genome sequence of Anaeromyxobacter sp. Fw109-5, isolated from nitrate- and uranium-contaminated subsurface sediment of the Oak Ridge Integrated Field-Scale Subsurface Research Challenge (IFC) site, Oak Ridge Reservation, TN. The bacterium’s genome sequence will elucidate its physiological potential in subsurface sediments undergoing in situ uranium bioremediation and natural attenuation.

  12. Complete genome sequence of Anaeromyxobacter sp. Fw109-5, an Anaerobic, Metal-Reducing Bacterium Isolated from a Contaminated Subsurface Environment

    SciTech Connect

    Hwang, C.; Copeland, A.; Lucas, Susan; Lapidus, Alla; Barry, Kerrie W.; Glavina del Rio, T.; Dalin, Eileen; Tice, Hope; Pitluck, S.; Sims, David R.; Brettin, T.; Bruce, David; Detter, J. C.; Han, Cliff F.; Schmutz, Jeremy; Larimer, F.; Land, M.; Hauser, L.; Kyrpides, Nikos C.; Lykidis, Athanasios; Richardson, P. M.; Beliaev, Alex S.; Sanford, Robert A.; Loeffler, Frank E.; Fields, Matthew W.

    2015-01-22

    We report the genome sequence of Anaeromyxobacter sp. Fw109-5, isolated from nitrate- and uranium-contaminated subsurface sediment of the Oak Ridge Integrated Field-Scale Subsurface Research Challenge (IFC) site, Oak Ridge Reservation, TN. The bacterium’s genome sequence will elucidate its physiological potential in subsurface sediments undergoing in situ uranium bioremediation and natural attenuation.

  13. Comparative study on toxicity evaluation of anaerobically treated parboiled rice manufacturing wastewater through fish bioassay.

    PubMed

    Giri, Dipti Ramesh; Singh, Ekta; Satyanarayan, Shanta

    2016-01-01

    Short term aquatic bioassay has been developed into a useful tool in water quality management. These tests give information on comparative toxicity of several compounds. The objective of this study was to evaluate the acute toxicity of raw and anaerobically treated effluents of the parboiled rice manufacturing industry. The acute toxicity test was carried out by using the fish Lebistes reticulatus under laboratory conditions. LC50 values for 24, 48, 72 and 96 hours ranged between 4.6 and 7.0% for the raw parboiled rice manufacturing wastewater. Two anaerobic fixed film fixed bed reactors and two different media matrices, i.e. UV stabilized Biopac media and Fugino spirals, were used for the treatment of parboiled rice mill wastewater. Effluents from these two reactors depicted LC50 values in the range of 68-88% and 62-78% for Biopac and Fugino spiral packed reactors, respectively. From the results, it is evident that anaerobically treated effluents from Biopac packed reactor is marginally better than Fugino spiral packed reactor. Results subjected to statistical evaluation depicted regression coefficient of more than 0.9 indicating good correlation between the mortality and effluent concentration.

  14. Livestock Anaerobic Digester Database

    EPA Pesticide Factsheets

    The Anaerobic Digester Database provides basic information about anaerobic digesters on livestock farms in the United States, organized in Excel spreadsheets. It includes projects that are under construction, operating, or shut down.

  15. Quinolone activity against anaerobes.

    PubMed

    Appelbaum, P C

    1999-01-01

    The first generation of fluoroquinolones such as ciprofloxacin and ofloxacin are inactive against most anaerobic bacteria. However, some broad-spectrum quinolones, which have recently become clinically available or are under active development, have significant antianaerobic activity. This review summarises the in vitro activity of currently available, as well as experimental, quinolones against clinically significant anaerobic bacteria. Quinolones with low activity against anaerobes include ciprofloxacin, ofloxacin, levofloxacin, fleroxacin, pefloxacin, enoxacin and lomefloxacin. Compounds with intermediate antianaerobic activity include sparfloxacin and grepafloxacin. Trovafloxacin, gatifloxacin and moxifloxacin yield low MICs against most groups of anaerobes. Quinolones with the greatest in vitro activity against anaerobes include clinafloxacin and sitafloxacin (DU-6859a).

  16. Draft Genome Sequence of the Cellulolytic Strain Clostridium sp. Bc-iso-3 Isolated from an Industrial-Scale Anaerobic Digester

    PubMed Central

    2016-01-01

    Clostridium sp. Bc-iso-3 is a cellulolytic strain isolated from a Swedish industrial-scale biogas digester. Here, we present the draft genome sequence of this strain, which consists of four contigs with a total length of 4,327,139 bp and an average coverage of 312.97×. PMID:27789641

  17. An endo-beta-1,4-glucanase gene (celA) from the rumen anaerobe Ruminococcus albus 8: cloning, sequencing, and transcriptional analysis.

    PubMed

    Attwood, G T; Herrera, F; Weissenstein, L A; White, B A

    1996-03-01

    A genomic library of Ruminococcus albus 8 DNA was constructed in Escherichia coli using bacteriophage lambda ZapII. This library was screened for cellulase components and several Ostazin brilliant red/carboxymethyl cellulose positive clones were isolated. All of these clones contained a common 3.4-kb insert, which was recovered as a plasmid by helper phage excision. The carboxymethyl cellulase coding region was localized to a 1.4-kb region of DNA by nested deletions, and a clone containing the entire celA gene was sequenced. Analysis of the sequence revealed a 1231-bp open reading frame, coding for a protein of 411 amino acids with a predicted molecular weight of 45 747. This protein, designated CelA, showed extensive homology with family 5 endoglucanases by both primary amino acid sequence alignment and hydrophobic cluster analysis. Cell-free extracts of E. coli containing the celA clone demonstrated activity against carboxymethyl cellulose and acid swollen cellulose but not against any of the p-nitrophenol glycosides tested, indicating an endo-beta-1,4-glucanase type of activity. In vitro transcription-translation experiments showed that three proteins of 48,000, 44,000, and 23,000 molecular weight were produced by clones containing the celA gene. Northern analysis of RNA extracted from R. albus 8 grown on cellulose indicated a celA transcript of approximately 2700 bases, whereas when R. albus 8 was grown on cellobiose, celA transcripts of approximately 3000 and 600 bases were detected. Primer extension analysis of these RNAs revealed different transcription initiation sites for the celA gene when cells were grown with cellulose or cellobiose as the carbon source. These two sites differed by 370 bases in distance. A model, based on transcription and sequence data, is proposed for celA regulation.

  18. Anaerobic filters for the treatment of coal gasification wastewater.

    PubMed

    Suidan, M T; Siekerka, G L; Kao, S W; Pfeffer, J T

    1983-06-01

    A process train consisting of the following sequence of unit processes, a berl-saddle-packed anaerobic filter, an expanded bed, granular activated carbon anaerobic filter, and an activated sludge nitrification system was evaluated for the treatment of a synthetically prepared coal gasification wastewater. The first-stage anaerobic filter resulted in very little removal of organic matter and no methane production. Excellent reduction in organic matter occurred in the granular activated carbon anaerobic filter. The removal mechanism was initially adsorptive and near the end of the study, removal of organic matter was primarily through conversion to methane gas. It is felt that the success of the activated carbon anaerobic filter was due to the ability of the activated carbon to sequester some components of the wastewater that were toxic to the mixed culture of anaerobic microorganisms. The activated sludge nitrification system resulted in complete ammonia oxidation and was very efficient in final effluent polishing.

  19. Biochemistry and evolution of anaerobic energy metabolism in eukaryotes.

    PubMed

    Müller, Miklós; Mentel, Marek; van Hellemond, Jaap J; Henze, Katrin; Woehle, Christian; Gould, Sven B; Yu, Re-Young; van der Giezen, Mark; Tielens, Aloysius G M; Martin, William F

    2012-06-01

    Major insights into the phylogenetic distribution, biochemistry, and evolutionary significance of organelles involved in ATP synthesis (energy metabolism) in eukaryotes that thrive in anaerobic environments for all or part of their life cycles have accrued in recent years. All known eukaryotic groups possess an organelle of mitochondrial origin, mapping the origin of mitochondria to the eukaryotic common ancestor, and genome sequence data are rapidly accumulating for eukaryotes that possess anaerobic mitochondria, hydrogenosomes, or mitosomes. Here we review the available biochemical data on the enzymes and pathways that eukaryotes use in anaerobic energy metabolism and summarize the metabolic end products that they generate in their anaerobic habitats, focusing on the biochemical roles that their mitochondria play in anaerobic ATP synthesis. We present metabolic maps of compartmentalized energy metabolism for 16 well-studied species. There are currently no enzymes of core anaerobic energy metabolism that are specific to any of the six eukaryotic supergroup lineages; genes present in one supergroup are also found in at least one other supergroup. The gene distribution across lineages thus reflects the presence of anaerobic energy metabolism in the eukaryote common ancestor and differential loss during the specialization of some lineages to oxic niches, just as oxphos capabilities have been differentially lost in specialization to anoxic niches and the parasitic life-style. Some facultative anaerobes have retained both aerobic and anaerobic pathways. Diversified eukaryotic lineages have retained the same enzymes of anaerobic ATP synthesis, in line with geochemical data indicating low environmental oxygen levels while eukaryotes arose and diversified.

  20. An integrated anaerobic digestion and UV photocatalytic treatment of distillery wastewater.

    PubMed

    Apollo, Seth; Onyango, Maurice S; Ochieng, Aoyi

    2013-10-15

    Anaerobic up-flow fixed bed reactor and annular photocatalytic reactor were used to study the efficiency of integrated anaerobic digestion (AD) and ultraviolet (UV) photodegradation of real distillery effluent and raw molasses wastewater (MWW). It was found that UV photodegradation as a stand-alone technique achieved colour removal of 54% and 69% for the distillery and MWW, respectively, with a COD reduction of <20% and a negligible BOD reduction. On the other hand, AD as a single treatment technique was found to be effective in COD and BOD reduction with efficiencies of above 75% and 85%, respectively, for both wastewater samples. However, the AD achieved low colour removal efficiency, with an increase in colour intensity of 13% recorded when treating MWW while a colour removal of 51% was achieved for the distillery effluent. The application of UV photodegradation as a pre-treatment method to the AD process reduced the COD removal and biogas production efficiency. However, an integration in which UV photodegradation was employed as a post-treatment to the AD process achieved high COD removal of above 85% for both wastewater samples, and colour removal of 88% for the distillery effluent. Thus, photodegradation can be employed as a post-treatment technique to an AD system treating distillery effluent for complete removal of the biorecalcitrant and colour imparting compounds. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Kinetic parameters estimation in an anaerobic digestion process using successive quadratic programming.

    PubMed

    Aceves-Lara, C A; Aguilar-Garnica, E; Alcaraz-González, V; González-Reynoso, O; Steyer, J P; Dominguez-Beltran, J L; González-Alvarez, V

    2005-01-01

    In this work, an optimization method is implemented in an anaerobic digestion model to estimate its kinetic parameters and yield coefficients. This method combines the use of advanced state estimation schemes and powerful nonlinear programming techniques to yield fast and accurate estimates of the aforementioned parameters. In this method, we first implement an asymptotic observer to provide estimates of the non-measured variables (such as biomass concentration) and good guesses for the initial conditions of the parameter estimation algorithm. These results are then used by the successive quadratic programming (SQP) technique to calculate the kinetic parameters and yield coefficients of the anaerobic digestion process. The model, provided with the estimated parameters, is tested with experimental data from a pilot-scale fixed bed reactor treating raw industrial wine distillery wastewater. It is shown that SQP reaches a fast and accurate estimation of the kinetic parameters despite highly noise corrupted experimental data and time varying inputs variables. A statistical analysis is also performed to validate the combined estimation method. Finally, a comparison between the proposed method and the traditional Marquardt technique shows that both yield similar results; however, the calculation time of the traditional technique is considerable higher than that of the proposed method.

  2. Evaluation of a four year experience with a fully instrumented anaerobic digestion process.

    PubMed

    Steyer, J P; Bouvier, J C; Conte, T; Gras, P; Sousbie, P

    2002-01-01

    For several years, a 1 m3 fixed bed anaerobic digestion process has been operated for the treatment of distillery vinasses. This reactor has been fully instrumented with the following variables available on-line: pH, temperature, liquid and gas flow rates, gas composition (i.e., CH4, CO2 and H2), concentration of bicarbonate, chemical oxygen demand, total organic carbon, volatile fatty acids and partial and total alkalinity, these last four variables being measured twice by different techniques (i.e., using a TOC analyzer, a titrimetric sensor and an infrared spectrometer). The purpose of this paper is to compare the respective benefits of advanced instrumentation for the monitoring of wastewater treatment processes in general, and for anaerobic digestion in particular. It will also provide some statistical analysis of the time required to operate a fully instrumented wastewater treatment process. It is indeed well admitted in the literature that instrumentation is usually the main limitation step for using closed-loop control. However, it is our opinion that, in the near future, this situation will change. This point is discussed based on our four years practical experience.

  3. Two amplicon sequencing strategies revealed different facets of the prokaryotic community associated with the anaerobic treatment of vinasses from ethanol distilleries.

    PubMed

    Martínez, M A; Romero, H; Perotti, N I

    2014-02-01

    The prokaryotic consortium from a pilot-scale UASB reactor fed with vinasses from ethanol distilleries was evaluated by means of amplicon sequencing of the 16S rRNA gene. Two different sets of primers targeted to overlapping regions of the V4-16S region were used to gain a broad picture of such community and to perform a comparative analysis. From the two datasets obtained, prevalent phyla were Firmicutes, Verrucomicrobia and Thermotogae. Interestingly, one set of primers captured variability in both the bacterial and archaeal portions of the community, whilst the other one revealed a more diverse community structure, but only in the Bacteria domain. Although a certain level of agreement between the two strategies was observed, sharp differences indicate that different facets of the community were disclosed by each approach.

  4. Biohydrogen production from Tequila vinasses in an anaerobic sequencing batch reactor: effect of initial substrate concentration, temperature and hydraulic retention time.

    PubMed

    Buitrón, Germán; Carvajal, Carolina

    2010-12-01

    The effect of the temperature (25 and 35 degrees C), the hydraulic retention time, HRT, (12 and 24 h) and initial substrate concentration on hydrogen production from Tequila vinasse was studied using a sequencing batch reactor. When 25 degrees C and 12-h HRT were applied, only insignificant biogas quantities were produced; however, using 24 h of HRT and temperatures of 25 and 35 degrees C, biogas containing hydrogen was produced. A maximum volumetric hydrogen production rate of 50.5 mL H(2) L(-1) h(-1) (48 mmol H(2) L(reactor)(-1) d(-1)) and an average hydrogen content in the biogas of 29.2+/-8.8% were obtained when the reactor was fed with 3 g COD L(-1), at 35 degrees C and 12-h HRT. Methane formation was observed when the longer HRT was applied. Results demonstrated the feasibility to produce hydrogen from this waste without a previous pre-treatment.

  5. Non-contiguous finished genome sequence and description of Sulfurimonas hongkongensis sp. nov., a strictly anaerobic denitrifying, hydrogen- and sulfur-oxidizing chemolithoautotroph isolated from marine sediment.

    PubMed

    Cai, Lin; Shao, Ming-Fei; Zhang, Tong

    2014-06-15

    Here, we report a type strain AST-10 representing a novel species Sulfurimonas hongkongensis within Epsilonproteobacteria, which is involved in marine sedimentary sulfur oxidation and denitrification. Strain AST-10(T) (= DSM 22096(T) = JCM 18418(T)) was isolated from the coastal sediment at the Kai Tak Approach Channel connected to Victoria Harbour in Hong Kong. It grew chemolithoautotrophically using thiosulfate, sulfide or hydrogen as the sole electron donor and nitrate as the electron acceptor under anoxic conditions. It was rod-shaped and grew at 15-35°C (optimum at 30°C), pH 6.5-8.5 (optimum at 7.0-7.5), and 10-60 g L(-1) NaCl (optimum at 30 g L(-1)). Genome sequencing and annotation of strain AST-10(T) showed a 2,302,023 bp genome size, with 34.9% GC content, 2,290 protein-coding genes, and 42 RNA genes, including 3 rRNA genes.

  6. Anaerobic thermophilic culture

    DOEpatents

    Ljungdahl, Lars G.; Wiegel, Jurgen K. W.

    1981-01-01

    A newly discovered thermophilic anaerobe is described that was isolated in a biologically pure culture and designated Thermoanaerobacter ethanolicus ATCC 3/550. T. Ethanolicus is cultured in aqueous nutrient medium under anaerobic, thermophilic conditions and is used in a novel process for producing ethanol by subjecting carbohydrates, particularly the saccharides, to fermentation action of the new microorganism in a biologically pure culture.

  7. Anaerobic bag culture method.

    PubMed Central

    Rosenblatt, J E; Stewart, P R

    1975-01-01

    In a new method of anaerobic culture, a transparent, gas-impermeable bag is used and the anaerobic environment is established with copper sulfate-saturated steel wool. An Alka-Seltzer tablet generates carbon dioxide. The agar plate surface can be inspected through the bag at any time without interrupting the anaerobic atmosphere or disturbing other specimens. Methylene blue indicator strips are completely reduced by 4 h after the bag is set up and have remained reduced for as long as 3 weeks. Growth of 16 different stock culture anaerobes was generally equivalent by the bag and GasPak jar methods. Yield and growth of anaerobic isolates also were equivalent with 7 of 10 clinical specimens; from the other 3 specimens, 13 isolates were recovered, 5 by both the bag and jar methods and the rest by one method or the other. No consistent differences were found between the anaerobic bag and GasPak jar methods in the yield of anaerobes from clinical specimens. Early growth (24 h of incubation) of anaerobes from one specimen was detected with the bag method. Images PMID:1100671

  8. Anaerobic bag culture method.

    PubMed

    Rosenblatt, J E; Stewart, P R

    1975-06-01

    In a new method of anaerobic culture, a transparent, gas-impermeable bag is used and the anaerobic environment is established with copper sulfate-saturated steel wool. An Alka-Seltzer tablet generates carbon dioxide. The agar plate surface can be inspected through the bag at any time without interrupting the anaerobic atmosphere or disturbing other specimens. Methylene blue indicator strips are completely reduced by 4 h after the bag is set up and have remained reduced for as long as 3 weeks. Growth of 16 different stock culture anaerobes was generally equivalent by the bag and GasPak jar methods. Yield and growth of anaerobic isolates also were equivalent with 7 of 10 clinical specimens; from the other 3 specimens, 13 isolates were recovered, 5 by both the bag and jar methods and the rest by one method or the other. No consistent differences were found between the anaerobic bag and GasPak jar methods in the yield of anaerobes from clinical specimens. Early growth (24 h of incubation) of anaerobes from one specimen was detected with the bag method.

  9. Anaerobic digestion of ice-cream wastewater: A comparison of single and two-phase reactor systems

    SciTech Connect

    Borja, R.; Banks, C.J.

    1995-03-01

    The anaerobic digestion of ice-cream wastewater, a complex substrate which includes milk proteins, carbohydrates, and lipids, has received little attention. Work using an aerobic contact system showed that at a 7.5-d hydraulic retention time (HRT), with an organic loading rate of 1.7 g COD/Ld and influent TSS (total suspended solids) of 5870 mg/L, the effluent COD was 628 mg/L, BOD was 91 mg/L and TSS was 674. Anaerobic filters have also been used at organic loadings of 6 kg COD/m{sup 3}d applied at a HRT of 0.42 day, with COD removals of 80%. Goodwing showed that this waste was capable of being treated by the UASB process with granulation commencing after 60-70 days, and gas production ranging between 0.73 and 0.93 L CH{sub 4}/g COD removed with loading rates between 0.7 and 3.0 g TOC/Ld. Two-phase anaerobic digestion is an innovative fermentation mode that has recently received increased attention. The kinetically dissimilar fermentation phases, hydrolysis-acidification and acetogenesis-methanation are operated in two separate reactors; the first of which is maintained at a very short HRT. The effluent from the first, acid-forming, phase is used as the substrate for the methane-phase reactor which has a longer HRT or cell immobilization. The aim of this work was to compare the methane production capability and performance of a single-phase upflow fixed bed reactor with a two-phase digestion system. The two-phase digestion system consists of a completely mixed reactor for the acidogenic reaction and an upflow fixed bed reactor for the methanogenic reaction. Because of the high lipid content and COD of ice cream wastewater off site disposal has proved to be both expensive and poses problems to the receiving effluent treatment plant. For this reason the potential for a rapid anaerobic stabilization of the waste, with energy recovery in the form of methane gas, has been investigated in an attempt to minimize plant size and maximize gas production. 9 refs., 2 tabs.

  10. Anaerobic performance at altitude.

    PubMed

    Coudert, J

    1992-10-01

    Anaerobic metabolism is usually evaluated by the determination of the anaerobic capacity and the maximal anaerobic mechanical external power (Wmax). Conflicting results are reported on anaerobic capacity evaluated by maximal oxygen deficit and debt, and maximal blood lactate concentration during acute or chronic hypoxia (acclimatized subjects). Data on muscle biopsies (lactate concentration, changes in ATP, phosphocreatine and glycogen stores, glycolytic enzyme activities) and the few studies on lactate flux give in most cases evidence of a non-alteration of the anaerobic capacity for altitudes up to 5,500 m. No differences are observed in Wmax measured at high altitudes up to 5,200 m during intense short-term exercises: (1) jumps on a force platform which is a good indicator of alactic Wmax, and (2) 7-10 s sprints (i.e. force-velocity test) which solicit alactic metabolism but also lactic pathway. For exercises of duration equal or more than 30 s (i.e. Wingate test), there are conflicting results because a lower participation of aerobic metabolism during this test at high altitude can interfere with anaerobic performance. In conclusion, we can admit that anaerobic performances are not altered by high altitudes up to 5,200 m if the length of exposure does not exceed 5 weeks. After this period, muscle mass begins to decrease.

  11. Anaerobic Digestion and its Applications

    EPA Science Inventory

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  12. Anaerobic Digestion and its Applications

    EPA Science Inventory

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  13. Anaerobic lipid degradation through acidification and methanization.

    PubMed

    Kim, Ijung; Kim, Sang-Hyoun; Shin, Hang-Sik; Jung, Jin-Young

    2010-01-01

    In biological wastewater treatment high lipid concentration is known to inhibit microorganisms and cause active biomass flotation. To reduce lipid inhibition, a two-phase anaerobic system, consisting of an anaerobic sequencing batch reactor (ASBR) and an upflow anaerobic sludge blanket (UASB) reactor, was applied to synthetic dairy wastewater. During 153 days of operation, the two-phase system showed stable performance in lipid degradation. In the ASBR, a 13% lipid removal efficiency and 10% double bond removal efficiency were maintained. In the UASB, the chemical oxygen demand (COD), lipid and volatile fatty acid (VFA) removal efficiencies were more than 80%, 70% and 95%, respectively, up to organic loading rate 6.5 g COD/L/day. There were no operational problems such as serious scum formation or sludge washout. Protein degradation occurred prior to degradation during acidogenesis.

  14. Anaerobic energy metabolism in unicellular photosynthetic eukaryotes.

    PubMed

    Atteia, Ariane; van Lis, Robert; Tielens, Aloysius G M; Martin, William F

    2013-02-01

    Anaerobic metabolic pathways allow unicellular organisms to tolerate or colonize anoxic environments. Over the past ten years, genome sequencing projects have brought a new light on the extent of anaerobic metabolism in eukaryotes. A surprising development has been that free-living unicellular algae capable of photoautotrophic lifestyle are, in terms of their enzymatic repertoire, among the best equipped eukaryotes known when it comes to anaerobic energy metabolism. Some of these algae are marine organisms, common in the oceans, others are more typically soil inhabitants. All these species are important from the ecological (O(2)/CO(2) budget), biotechnological, and evolutionary perspectives. In the unicellular algae surveyed here, mixed-acid type fermentations are widespread while anaerobic respiration, which is more typical of eukaryotic heterotrophs, appears to be rare. The presence of a core anaerobic metabolism among the algae provides insights into its evolutionary origin, which traces to the eukaryote common ancestor. The predicted fermentative enzymes often exhibit an amino acid extension at the N-terminus, suggesting that these proteins might be compartmentalized in the cell, likely in the chloroplast or the mitochondrion. The green algae Chlamydomonas reinhardtii and Chlorella NC64 have the most extended set of fermentative enzymes reported so far. Among the eukaryotes with secondary plastids, the diatom Thalassiosira pseudonana has the most pronounced anaerobic capabilities as yet. From the standpoints of genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism in C. reinhardtii remains the best characterized among photosynthetic protists. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Anaerobic brain abscess

    PubMed Central

    Sudhaharan, Sukanya; Chavali, Padmasri

    2016-01-01

    Background and Objectives: Brain abscess remains a potentially fatal central nervous system (CNS) disease, especially in developing countries. Anaerobic abscess is difficult to diagnose because of cumbersome procedures associated with the isolation of anaerobes. Materials and Methods: This is a hospital-based retrospective microbiological analysis of 430 brain abscess materials (purulent aspirates and/or tissue), for anaerobic organisms, that were received between 1987–2014, by the Microbiology Laboratory in our Institute. Results: Culture showed growth of bacteria 116/430 (27%) of the cases of which anaerobes were isolated in 48/116 (41.1%) of the cases. Peptostreptococcus (51.4 %), was the predominant organism isolated in four cases followed by Bacteroides and Peptococcus species. Conclusion: Early diagnosis and detection of these organisms would help in the appropriate management of these patients. PMID:27307977

  16. Anaerobic bacteria from hypersaline environments.

    PubMed Central

    Ollivier, B; Caumette, P; Garcia, J L; Mah, R A

    1994-01-01

    Strictly anaerobic halophiles, namely fermentative, sulfate-reducing, homoacetogenic, phototrophic, and methanogenic bacteria are involved in the oxidation of organic carbon in hypersaline environments. To date, six anaerobic fermentative genera, containing nine species, have been described. Two of them are homoacetogens. Six species belong to the family Haloanaerobiaceae, as indicated by their unique 16S rRNA oligonucleotide sequences. Desulfohalobium retbaense and Desulfovibrio halophilus represent the only two moderately halophilic sulfate reducers so far reported. Among anoxygenic phototrophic anaerobes, a few purple bacteria with optimal growth at salinities between 6 and 11% NaCl have been isolated from hypersaline habitats. They belong to the genera Rhodospirillum, Chromatium, Thiocapsa, and Ectothiorhodospira. The commonest organisms isolated so far are Chromatium salexigens, Thiocapsa halophila, and Rhodospirillum salinarum. Extremely halophilic purple bacteria have most commonly been isolated from alkaline brines and require about 20 to 25% NaCl for optimal growth. They belong to the family Ectothiorodhospiraceae. Their osmoregulation involves synthesis or uptake of compatible solutes such as glycine-betaine that accumulate in their cytoplasm. The existence of methanogens in hypersaline environments is related to the presence of noncompetitive substrates such as methylamines, which originate mainly from the breakdown of osmoregulatory amines. Methanogenesis probably does not contribute to the mineralization of carbohydrates at NaCl concentrations higher than 15%. Above this concentration, sulfate reduction is probably the main way to oxidize H2 (although at rates too low to use up all the H2 formed) and occupies a terminal function kn the degradation of carbohydrates. Three genera and five species of halophilic methylotrophic methanogens have been reported. A bloom of phototrophic bacteria in the marine salterns of Salins-de-Giraud, located on the

  17. Anaerobic bacteria from hypersaline environments.

    PubMed

    Ollivier, B; Caumette, P; Garcia, J L; Mah, R A

    1994-03-01

    Strictly anaerobic halophiles, namely fermentative, sulfate-reducing, homoacetogenic, phototrophic, and methanogenic bacteria are involved in the oxidation of organic carbon in hypersaline environments. To date, six anaerobic fermentative genera, containing nine species, have been described. Two of them are homoacetogens. Six species belong to the family Haloanaerobiaceae, as indicated by their unique 16S rRNA oligonucleotide sequences. Desulfohalobium retbaense and Desulfovibrio halophilus represent the only two moderately halophilic sulfate reducers so far reported. Among anoxygenic phototrophic anaerobes, a few purple bacteria with optimal growth at salinities between 6 and 11% NaCl have been isolated from hypersaline habitats. They belong to the genera Rhodospirillum, Chromatium, Thiocapsa, and Ectothiorhodospira. The commonest organisms isolated so far are Chromatium salexigens, Thiocapsa halophila, and Rhodospirillum salinarum. Extremely halophilic purple bacteria have most commonly been isolated from alkaline brines and require about 20 to 25% NaCl for optimal growth. They belong to the family Ectothiorodhospiraceae. Their osmoregulation involves synthesis or uptake of compatible solutes such as glycine-betaine that accumulate in their cytoplasm. The existence of methanogens in hypersaline environments is related to the presence of noncompetitive substrates such as methylamines, which originate mainly from the breakdown of osmoregulatory amines. Methanogenesis probably does not contribute to the mineralization of carbohydrates at NaCl concentrations higher than 15%. Above this concentration, sulfate reduction is probably the main way to oxidize H2 (although at rates too low to use up all the H2 formed) and occupies a terminal function kn the degradation of carbohydrates. Three genera and five species of halophilic methylotrophic methanogens have been reported. A bloom of phototrophic bacteria in the marine salterns of Salins-de-Giraud, located on the

  18. Anaerobic Catabolism of Aromatic Compounds: a Genetic and Genomic View

    PubMed Central

    Carmona, Manuel; Zamarro, María Teresa; Blázquez, Blas; Durante-Rodríguez, Gonzalo; Juárez, Javier F.; Valderrama, J. Andrés; Barragán, María J. L.; García, José Luis; Díaz, Eduardo

    2009-01-01

    Summary: Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach. PMID:19258534

  19. Improvement of hydrogen production via ethanol-type fermentation in an anaerobic down-flow structured bed reactor.

    PubMed

    Anzola-Rojas, Mélida del Pilar; Zaiat, Marcelo; De Wever, Heleen

    2016-02-01

    Although a novel anaerobic down-flow structured bed reactor has shown feasibility and stable performance for a long-term compared to other anaerobic fixed bed systems for continuous hydrogen production, the volumetric rates and yields have so far been too low. In order to improve the performance, an operation strategy was applied by organic loading rate (OLR) variation (12-96 g COD L(-1) d(-1)). Different volumetric hydrogen rates, and yields at the same OLR indicated that the system was mainly driven by the specific organic load (SOL). When SOL was kept between 3.8 and 6.2 g sucrose g(-1) VSS d(-1), the volumetric rates raised from 0.1 to 8.9 L H2 L(-1) d(-1), and the yields were stable around 2.0 mol H2 mol(-1) converted sucrose. Furthermore, hydrogen was produced mainly via ethanol-type fermentation, reaching a total energy conversion rate of 23.40 kJ h(-1) L(-1) based on both hydrogen and ethanol production.

  20. Gender comparisons in anaerobic power and anaerobic capacity tests.

    PubMed Central

    Maud, P J; Shultz, B B

    1986-01-01

    The purpose of the study was to compare anaerobic power and anaerobic capacity test scores between young active men and women. Three performance measures of anaerobic power and two of anaerobic capacity were administered to a sample comprising 52 male and 50 female college students (means age = 21.4 yrs). Results indicated significant differences between men and women in body height, weight and per cent fat, in fat free mass (FFM), anaerobic power, and anaerobic capacity when recorded as gross work completed and relative to body weight. However, these differences are reduced when data is adjusted for body weight and further reduced when corrected for FFM. The study found no significant differences between men and women in either anaerobic power or anaerobic capacity when values were given relative to FFM. PMID:3730753

  1. Diversity Profile of Microbes Associated with Anaerobic Sulfur Oxidation in an Upflow Anaerobic Sludge Blanket Reactor Treating Municipal Sewage

    PubMed Central

    Aida, Azrina A.; Kuroda, Kyohei; Yamamoto, Masamitsu; Nakamura, Akinobu; Hatamoto, Masashi; Yamaguchi, Takashi

    2015-01-01

    We herein analyzed the diversity of microbes involved in anaerobic sulfur oxidation in an upflow anaerobic sludge blanket (UASB) reactor used for treating municipal sewage under low-temperature conditions. Anaerobic sulfur oxidation occurred in the absence of oxygen, with nitrite and nitrate as electron acceptors; however, reactor performance parameters demonstrated that anaerobic conditions were maintained. In order to gain insights into the underlying basis of anaerobic sulfur oxidation, the microbial diversity that exists in the UASB sludge was analyzed comprehensively to determine their identities and contribution to sulfur oxidation. Sludge samples were collected from the UASB reactor over a period of 2 years and used for bacterial 16S rRNA gene-based terminal restriction fragment length polymorphism (T-RFLP) and next-generation sequencing analyses. T-RFLP and sequencing results both showed that microbial community patterns changed markedly from day 537 onwards. Bacteria belonging to the genus Desulforhabdus within the phylum Proteobacteria and uncultured bacteria within the phylum Fusobacteria were the main groups observed during the period of anaerobic sulfur oxidation. Their abundance correlated with temperature, suggesting that these bacterial groups played roles in anaerobic sulfur oxidation in UASB reactors. PMID:25817585

  2. Biochemistry and Evolution of Anaerobic Energy Metabolism in Eukaryotes

    PubMed Central

    Müller, Miklós; Mentel, Marek; van Hellemond, Jaap J.; Henze, Katrin; Woehle, Christian; Gould, Sven B.; Yu, Re-Young; van der Giezen, Mark

    2012-01-01

    Summary: Major insights into the phylogenetic distribution, biochemistry, and evolutionary significance of organelles involved in ATP synthesis (energy metabolism) in eukaryotes that thrive in anaerobic environments for all or part of their life cycles have accrued in recent years. All known eukaryotic groups possess an organelle of mitochondrial origin, mapping the origin of mitochondria to the eukaryotic common ancestor, and genome sequence data are rapidly accumulating for eukaryotes that possess anaerobic mitochondria, hydrogenosomes, or mitosomes. Here we review the available biochemical data on the enzymes and pathways that eukaryotes use in anaerobic energy metabolism and summarize the metabolic end products that they generate in their anaerobic habitats, focusing on the biochemical roles that their mitochondria play in anaerobic ATP synthesis. We present metabolic maps of compartmentalized energy metabolism for 16 well-studied species. There are currently no enzymes of core anaerobic energy metabolism that are specific to any of the six eukaryotic supergroup lineages; genes present in one supergroup are also found in at least one other supergroup. The gene distribution across lineages thus reflects the presence of anaerobic energy metabolism in the eukaryote common ancestor and differential loss during the specialization of some lineages to oxic niches, just as oxphos capabilities have been differentially lost in specialization to anoxic niches and the parasitic life-style. Some facultative anaerobes have retained both aerobic and anaerobic pathways. Diversified eukaryotic lineages have retained the same enzymes of anaerobic ATP synthesis, in line with geochemical data indicating low environmental oxygen levels while eukaryotes arose and diversified. PMID:22688819

  3. Hemicellulases from anaerobic thermophiles. Progress report

    SciTech Connect

    Wiegel, J.

    1994-05-01

    The longterm goal of this research effort is to obtain an anaerobic thermophilic bacterium that efficiently converts various hemicellulose-containing biomass to ethanol over a broad pH range. The strategy is to modify the outfit and regulation of the rate-limiting xylanases, glycosidases and xylan esterases in the ethanologenic, anaerobic thermophile Thermoanaerobacter ethanolicus, which grows between pH 4.5 and 9.5. Although it utilizes xylans, the xylanase, acetyl(xylan) esterase and O-methylglucuronidase activities in T. ethanolicus are barely measurable and regarded as the rate limiting steps in its xylan utilization. Thus, and also due to the presently limited knowledge of hemicellulases in anaerobic thermophiles, we characterize the hemicellulolytic enzymes from this and other anaerobic thermophiles as enzyme donors. Beside the active xylosidase/arabinosidase from T. ethanolicus, exhibiting the two different activities, we characterized 2 xylosidases, two acetyl(xylan) esterases, and an O-methylglucuronidase from Thermoanaerobacterium spec. We will continue with the characterization of xylanases from novel isolated slightly acidophilic, neutrophilic and slightly alkalophilic thermophiles. We have cloned, subcloned and partially sequenced the 165,000 Da (2 x 85,000) xylosidase/arabinosidase from T. ethanolicus and started with the cloning of the esterases from Thermoanaerobacterium spec. Consequently, we will develop a shuttle vector and continue to apply electroporation of autoplasts as a method for cloning into T. ethanolicus.

  4. Anaerobic thermophilic culture system

    DOEpatents

    Ljungdahl, Lars G.; Wiegel, Jurgen K. W.

    1981-01-01

    A mixed culture system of the newly discovered microorganism Thermoanaerobacter ethanolicus ATCC31550 and the microorganism Clostridium thermocellum ATCC31549 is described. In a mixed nutrient culture medium that contains cellulose, these microorganisms have been coupled and cultivated to efficiently ferment cellulose to produce recoverable quantities of ethanol under anaerobic, thermophilic conditions.

  5. The anaerobic digestion process

    SciTech Connect

    Rivard, C.J.; Boone, D.R.

    1996-01-01

    The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

  6. Anaerobic digestion process

    SciTech Connect

    Ishida, M.; Haga, R.; Odawara, Y.

    1984-04-10

    First, the organic waste slurry of sewage sludge and/or kitchen garbage is stored in a stable condition after effecting partially thereto a liquefaction treatment in advance by adding liquefying bacteria, and next this slurry is effectively digested anaerobically by way of a liquefaction/gasification-mixed step or a liquefaction/gasification separated step.

  7. Effect of nitrate on anaerobic azo dye reduction.

    PubMed

    Cirik, Kevser; Kitiş, Mehmet; Çinar, Özer

    2013-01-01

    The aim of the study was to investigate the effect of nitrate on anaerobic color removal efficiencies. For this aim, anaerobic-aerobic sequencing batch reactor (SBR) fed with a simulated textile effluent including Remazol Brilliant Violet 5R azo dye was operated with a total cycle time of 12 h, including anaerobic (6 h) and aerobic cycles (6 h). Microorganism grown under anaerobic phase of the reactor was exposed to different amounts of competitive electron acceptor (nitrate) and performance of the system was determined by monitoring color removal efficiency, nitrate removal, nitrite formation and removal, oxidation reduction potential, color removal rate, chemical oxygen demand (COD), specific anaerobic enzyme (azo reductase) and aerobic enzyme (catechol 1,2 dioxygenase), and formation and removal of aromatic amines. Variations of population dynamics of microorganisms exposed to various amount of nitrate were identified by denaturing gradient gel electrophoresis (DGGE). It was found that nitrate has adverse effect on anaerobic color removal efficiency and color removal was achieved after denitrification process was completed. It was found that nitrate stimulates the COD removal efficiency and accelerates the COD removal in the first hour of anaerobic phase. About 90 % total COD removal efficiencies were achieved in which microorganism exposed to increasing amount of nitrate. Population dynamics of microorganisms exposed to various amount of nitrate were changed and diversity was increased.

  8. Large-scale spherical fixed bed reactors: Modeling and optimization

    SciTech Connect

    Hartig, F.; Keil, F.J. )

    1993-03-01

    Iterative dynamic programming (IDP) according to Luus was used for the optimization of the methanol production in a cascade of spherical reactors. The system of three spherical reactors was compared to an externally cooled tubular reactor and a quench reactor. The reactors were modeled by the pseudohomogeneous and heterogeneous approach. The effectiveness factors of the heterogeneous model were calculated by the dusty gas model. The IDP method was compared with sequential quadratic programming (SQP) and the Box complex method. The optimized distributions of catalyst volume with the pseudohomogeneous and heterogeneous model lead to different results. The IDP method finds the global optimum with high probability. A combination of IDP and SQP provides a reliable optimization procedure that needs minimum computing time.

  9. Wood Combustion Behaviour in a Fixed Bed Combustor

    NASA Astrophysics Data System (ADS)

    Tokit, Ernie Mat; Aziz, Azhar Abdul; Ghazali, Normah Mohd

    2010-06-01

    Waste wood is used as feedstock for Universiti Teknologi Malaysia's newly-developed two-stage incinerator system. The research goals are to optimize the operation of the thermal system to the primary chamber, to improve its combustion efficiency and to minimize its pollutants formation. The combustion process is evaluated with the variation of fuel's moisture content. For optimum operating condition, where the gasification efficiency is 95.53%, the moisture content of the fuel is best set at 17%; giving outlet operating temperature of 550°C and exhaust gas concentrations with 1213 ppm of CO, 6% of CO2 and 14% of O2 respectively. In line to the experimental work, a computational fluid dynamics software, Fluent is used to simulate the performance of the primary chamber. Here the predicted optimum gasification efficiency stands at 95.49% with CO, CO2 and O2 concentrations as 1301 ppm, 6.5% and 13.5% respectively.

  10. Direct Fixed-Bed Biological Perchlorate Destruction Demonstration

    DTIC Science & Technology

    2009-04-01

    largely gram-negative Proteobacteria ;5) site-specific performance of these systems can be predicted using a mathematical model developed as part of...bacterial communities in these systems are largely gram-negative Proteobacteria ; 5) site-specific performance of these systems can be 10 predicted...systems are largely gram-negative Proteobacteria ; 5) site-specific performance of these systems can be predicted using a mathematical model developed as

  11. Direct Fixed-Bed Biological Perchlorate Destruction Demonstration

    DTIC Science & Technology

    2008-09-01

    18  5.6  Sampling Methods ...Confirmation Methods ................................................................... 29  6.2  Demonstration Performance...Appendix D - Microbial Characterization Appendix E - Mathematical Modeling Results Appendix F - Analytical Methods Supporting the Experimental

  12. Can anaerobes be acid fast? A novel, clinically relevant acid fast anaerobe

    PubMed Central

    Jump, Robin; Canaday, David H.; Wnek, Maria D.; SenGupta, Dhruba J.; McQuiston, John R.; Bell, Melissa

    2016-01-01

    Introduction: Anaerobic acid fast bacilli (AFB) have not been previously reported in clinical microbiology. This is the second case report of a novel anaerobic AFB causing disease in humans. Case presentation: An anaerobic AFB was isolated from an abdominal wall abscess in a 64–year-old Caucasian diabetic male, who underwent distal pancreatectomy and splenectomy for resection of a pancreatic neuroendocrine tumour. The isolated bacteria were gram-variable and acid-fast, consisting of small irregular rods. The 16S rRNA gene sequence analysis showed that the isolate is a novel organism described in the literature only once before. The organism was studied at the CDC (Centers for Disease Control and Prevention) by the same group that worked with the isolates from the previous report; their findings suggest that the strain belongs to the suborder Corynebacterineae. Conclusion: This is the fifth reported case of an anaerobic AFB involved in clinical disease; its microbiological features and 16S RNA sequence are identical to previously reported cases. Clinical disease with this organism seems to be associated with recent history of surgery and abscess formation in deep soft tissues. Acquisition from surgical material is uncertain but seems unlikely. PMID:28348766

  13. Phylogenetic Analysis of an Anaerobic, Trichlorobenzene-Transforming Microbial Consortium

    PubMed Central

    von Wintzingerode, Friedrich; Selent, Burkhard; Hegemann, Werner; Göbel, Ulf B.

    1999-01-01

    A culture-independent phylogenetic survey for an anaerobic trichlorobenzene-transforming microbial community was carried out. Small-subunit rRNA genes were PCR amplified from community DNA by using primers specific for Bacteria or Euryarchaeota and were subsequently cloned. Application of a new hybridization-based screening approach revealed 51 bacterial clone families, one of which was closely related to dechlorinating Dehalobacter species. Several clone sequences clustered to rDNA sequences obtained from a molecular study of an anaerobic aquifer contaminated with hydrocarbons and chlorinated solvents (Dojka et al., Appl. Env. Microbiol. 64:3869–3877, 1998). PMID:9872791

  14. Effects of metal cations present naturally in coal on the fate of coal-bound nitrogen in the fixed-bed pyrolysis of 25 coals with different ranks: correlation between inherent Fe cations and N{sub 2} formation from low-rank coals

    SciTech Connect

    Yasuo Ohtsuka; Zhiheng Wu

    2009-09-15

    The fate of coal-N in the fixed-bed pyrolysis of 25 coals with 62-81 wt % (daf) C has been studied with a quartz reactor at 1000 C under ambient pressure to examine the effects of metal cations present naturally in these coals on the partitioning of coal-N into N{sub 2}, NH{sub 3}, HCN, tar-N, and char-N. Nitrogen mass balances for all runs fall within the reasonable range of 100 {+-} 5%, and N{sub 2} is the predominant product for all of the coals. As the N{sub 2} yield increases, the sum of NH{sub 3}, HCN, and tar-N is unchanged significantly, whereas the char-N yield decreases almost linearly, showing that most of N{sub 2} originates from char-N. When eight kinds of inherent metals, such as Na, Mg, Al, Si, K, Ca, Fe, and Ti, are determined by the conventional method and related with the N{sub 2} yield, there exists a strong, direct correlation between the Fe content and N{sub 2} formation for low-rank coals with less than 75 wt % (daf) C. Transmission electron microscopy coupled with an energy-dispersive analysis of X-rays (TEM-EDAX) measurements after pyrolysis at 1000{sup o}C of a German brown coal, which provides the highest N{sub 2} yield of about 60%, reveal the existence of lamella structures because of graphitized carbon as well as nanoscale Fe particles with different sizes and shapes. The mechanism for conversion reactions of char-N to N{sub 2} is discussed in terms of the catalysis by nanoparticles of metallic Fe formed from inherent Fe cations. 34 refs., 18 figs., 1 tab.

  15. Perspectives for anaerobic digestion.

    PubMed

    Ahring, Birgitte K

    2003-01-01

    The modern society generates large amounts of waste that represent a tremendous threat to the environment and human and animal health. To prevent and control this, a range of different waste treatment and disposal methods are used. The choice of method must always be based on maximum safety, minimum environmental impact and, as far as possible, on valorization of the waste and final recycling of the end products. One of the main trends of today's waste management policies is to reduce the stream of waste going to landfills and to recycle the organic material and the plant nutrients back to the soil. Anaerobic digestion (AD) is one way of achieving this goal and it will furthermore, reduce energy consumption or may even be net energy producing. This chapter aims at provide a basic understanding of the world in which anaerobic digestion is operating today. The newest process developments as well as future perspectives will be discussed.

  16. Anaerobic transformation of TNT

    SciTech Connect

    Kulpa, C.F.; Roopathy, R.

    1995-12-31

    Most studies on the microbial metabolism of nitroaromatic compounds have used aerobic tempts to degrade nitroaromatics under aerobic microorganisms. In many cases attempts to degrade nitroaromatics under aerobic conditions results in no mineralization and only superficial modifications of the structure. However, under anaerobic sulfate-reducing conditions, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. Trinitrotoluene under sulfate-reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitrate from trinitrotoluene is achieved by a series of reductive reactions with the production of ammonia and toluene by Desulfovibrio sp. (B strain). Similar metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. This presentation will review the data supporting the anaerobic transformation of TNT and other nitroaromatics.

  17. Anaerobic digestion process

    SciTech Connect

    Ishida, M.; Haga, R.; Odawara, Y.

    1982-10-19

    An algae culture grown on the water from the digested slurry of a biogasification plant serves as a means of removing CO/sub 2/ from the methane stream while purifying the wastewater and providing more biomass for the anaerobic digestion plant. Tested on a sewage-sludge digestion system, the proposed process improved the methane yield by 32% and methane concentration by 53-98 vol % while lowering the concentration of nitrogen and phosphorus in the final water.

  18. Early anaerobic metabolisms

    PubMed Central

    Canfield, Don E; Rosing, Minik T; Bjerrum, Christian

    2006-01-01

    Before the advent of oxygenic photosynthesis, the biosphere was driven by anaerobic metabolisms. We catalogue and quantify the source strengths of the most probable electron donors and electron acceptors that would have been available to fuel early-Earth ecosystems. The most active ecosystems were probably driven by the cycling of H2 and Fe2+ through primary production conducted by anoxygenic phototrophs. Interesting and dynamic ecosystems would have also been driven by the microbial cycling of sulphur and nitrogen species, but their activity levels were probably not so great. Despite the diversity of potential early ecosystems, rates of primary production in the early-Earth anaerobic biosphere were probably well below those rates observed in the marine environment. We shift our attention to the Earth environment at 3.8 Gyr ago, where the earliest marine sediments are preserved. We calculate, consistent with the carbon isotope record and other considerations of the carbon cycle, that marine rates of primary production at this time were probably an order of magnitude (or more) less than today. We conclude that the flux of reduced species to the Earth surface at this time may have been sufficient to drive anaerobic ecosystems of sufficient activity to be consistent with the carbon isotope record. Conversely, an ecosystem based on oxygenic photosynthesis was also possible with complete removal of the oxygen by reaction with reduced species from the mantle. PMID:17008221

  19. Simple Method for Culturing Anaerobes

    PubMed Central

    Davis, C. E.; Hunter, W. J.; Ryan, J. L.; Braude, A. I.

    1973-01-01

    A simple, effective method is needed for growing obligate anaerobes in the clinical laboratory. This report describes a pre-reduced anaerobic bottle that can be taken to the bedside for direct inoculation, provides a flat agar surface for evaluation of number and morphology of colonies, and can be incubated in conventional bacteriological incubators. Each anaerobic culture set consisted of two bottles containing brain heart infusion agar and CO2. Gentamicin sulfate (50 μg/ml) was added to one of these to inhibit facultative enteric bacilli. Comparison of the anaerobic bottles with an identical aerobic bottle which was also routinely inoculated permitted early identification of anaerobic colonies. Representative species of most anaerobic genera of proven pathogenicity for man have been isolated from this system during 10 months of routine use. Images PMID:4571657

  20. Candidatus Accumulibacter phosphatis clades enriched under cyclic anaerobic and microaerobic conditions simultaneously use different electron acceptors

    EPA Science Inventory

    Lab- and pilot-scale simultaneous nitrification, denitrification and phosphorus removal-sequencing batch reactors were operated under cyclic anaerobic and micro-aerobic conditions. The use of oxygen, nitrite, and nitrate as electron acceptors by Candidatus Accumulibacter phosphat...