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Sample records for eines styroleliminierenden biofilters

  1. Trimethylamine (TMA) biofiltration and transformation in biofilters.

    PubMed

    Ding, Ying; Shi, Ji-Yan; Wu, Wei-Xiang; Yin, Jun; Chen, Ying-Xu

    2007-05-08

    Bioremoval of trimethylamine (TMA) in two three-stage biofilters packed with compost (A) and sludge (B), respectively, was investigated. Both biofilters were operated with an influent TMA concentration of 19.2-57.2mgm(-3) for 67 days. Results showed that all of the inlet TMA could be removed by both biofilters. However, removal efficiency and transformation of TMA in each section of both biofilters was different. In the Introduction section, TMA removal efficiency and maximum elimination capacity of the compost medium were greater than those of sludge medium under higher inlet TMA concentration. In comparison with biofilter A, considerably higher NH(3) concentrations in effluent of all three sections in biofilter B were observed after day 19. Although, NO(2)(-)-N concentration in each section of biofilter A was relatively lower, NO(3)(-)-N content in each section of biofilter A increased after day 26, especially in the Materials and method section which increased remarkably due to a lesser amount of TMA and higher ammonia oxidation and nitrification in compost medium. In contrast, neither NO(2)(-)-N nor NO(3)(-)-N were detected in either section of biofilter B at any time throughout the course of the experiment. The cumulative results indicated that compost is more favorable for the growth of TMA-degrading and nitrifying bacteria as compared to the sludge and could be a highly suitable packing material for biodegradation and transformation of TMA.

  2. Modeling of trihalomethane cometabolism in nitrifying biofilters.

    PubMed

    Wahman, David G; Katz, Lynn E; Speitel, Gerald E

    2007-01-01

    The computer program AQUASIM was used to model biofilter experiments seeded with Lake Austin, Texas mixed-culture nitrifiers. These biofilters degraded four trihalomethanes (THMs) (trichloromethane (TCM) or chloroform, bromodichloromethane (BDCM), dibromochloromethane (DBCM), tribromomethane (TBM) or bromoform) commonly found in treated drinking water. Apparent steady-state data from the biofilter experiments and supporting batch experiments were used to estimate kinetic parameters for TCM, DBCM and ammonia degradation. Subsequently, the model was verified against other experimental biofilter data. To allow for full-scale simulations, BDCM and TBM rate constants were estimated using data from batch kinetic studies. Finally, the model was used to simulate full-scale filter performance under different filter surface loading rates and THM speciation seen in practice. Overall, total THM removals ranged from 16% to 54% in these simulations with influent total THM concentrations of 75-82microg/L, which illustrates the potential of THM cometabolism to have a significant impact on treated water quality.

  3. EIN Software Catalog.

    ERIC Educational Resources Information Center

    Interuniversity Communications Council (EDUCOM), Boston, MA.

    The EIN (Educational Information Network) is a non-profit operation which coordinates the sharing of educational computing resources. It is administered by EDUCOM and funded jointly by the U. S. Office of Education and the National Science Foundation. EIN maintains a group of contact personnel at member institutions to serve as a liaison between…

  4. Chabazite biofilter for enhanced stormwater nitrogen removal.

    PubMed

    Smith, Daniel P

    2011-04-01

    Enhanced nitrogen removal from stormwater using chabazite, a natural cation exchanger, was evaluated in a pilot-plant biofilter operated for 216 days. A parallel sand filter served as the control. The biofilters were subject to various operating modes including baseline periods of steady flowrate and loading, simulated high flowrate (storm) events following steady flowrates, high flowrates following extended no-flow periods, and with limited influent dissolved oxygen. Under steady-flow operation, chabazite removed 93% of ammonium and sand removed 87%; total inorganic nitrogen was reduced 35% by chabazite versus 15% by sand. In a simulated storm event following steady-flow operation, 97% of cumulative ammonia mass was retained by the chabazite biofilter versus 70% for sand. Following a 40 day no-flow period, the chabazite biofilter retained 98% of influent ammonium in a storm event while sand exhibited high effluent ammonium. Chabazite ammonium retention was high under limited influent dissolved oxygen, verses significant breakthrough by the sand biofilter. Chabazite media provided superior performance resiliency under dynamic conditions that typify stormwater treatment.

  5. Modeling of a compost biofilter incorporating microbial growth

    SciTech Connect

    Morgenroth, E.; Schroeder, E.D.; Chang, D.P.Y.; Scow, K.M.

    1995-11-01

    Biofiltration of air streams is gaining acceptance as an air pollution control technology. Biofilters are advantageous because of low operating costs and low energy requirements. Biofilters are advantageous for the removal of biodegradable pollutants at low concentrations. In this paper steady state and dynamic models for biofilters are presented. Analytical steady state models are useful for design purposes. The effects of changing operating conditions on removal efficiency and elimination capacity can be predicted. Dynamic models give a better representation of processes in a biofilter. A dynamic biofilter model incorporating microbial growth was developed. The dynamic model accounts for higher organism density at the inlet due to higher substrate concentrations.

  6. Biological waste air treatment in biofilters.

    PubMed

    Deshusses, M A

    1997-06-01

    Recent studies in the area of biological waste air treatment in biofilters have addressed fundamental key issues such as microbial dynamics, microscopical characterization of the process culture and oxygen and nutrient limitations. The results from these studies have provided a deeper insight into the overall biofiltration process. In the coming years, such advances should allow for the design of better reactor controls and the improvement of pollutant removal in gas-phase bioreactors.

  7. Modeling and simulation of a biofilter

    SciTech Connect

    Amanullah, M.; Farooq, S.; Viswanathan, S.

    1999-07-01

    Treatment of air streams contaminated with volatile organic compounds in a biofilter under transient and steady-state conditions of operation is described with a mathematical model. The model incorporates convection and dispersion in the gas phase, partial coverage of the solid support, interphase mass transfer between the gas and the aqueous biofilm with an equilibrium partition at the interface followed by diffusion, direct adsorption to the exposed uncovered solid adsorbent media, transfer between the biofilm and the solid support, and biological reactions in both the biofilm and the adsorbent. The model equations were solved numerically by the method of orthogonal collocation using a MATLAB computer code. The effects of pollutant dispersion in the gas phase, specific surface area available for mass transfer, thickness of the biofilm, and adsorptive capacity of the solid support on the biofilter performance were investigated in detail. The steady-state removal efficiency appears to be nearly independent of gas-phase dispersion of the pollutant in the normal industrial range of operations. Results also indicate that the biofilter performance is a strong function of specific surface area for mass transfer and biofilm thickness. Simulation results further suggest that higher adsorptive support media are capable of handling load fluctuations irrespective of the rate of reaction in the adsorbed phase.

  8. Design and management of conventional fluidized-sand biofilters

    USDA-ARS?s Scientific Manuscript database

    Fluidized sand biofilters (FSBs) are relatively compact, efficient, and cost-competitive biofilters, especially in recirculating systems that require maintaining consistently low levels of ammonia and nitrite. Filter sand is low cost (often $70-200/m3 of sand delivered) and has a high specific surf...

  9. Methane oxidation in water-spreading and compost biofilters.

    PubMed

    Powelson, David K; Chanton, Jeffery; Abichou, Tarek; Morales, Jose

    2006-12-01

    This study evaluated two biofilter designs to mitigate methane emissions from landfill vents. Water-spreading biofilters were designed to use the capillarity of coarse sand overlain by a finer sand to increase the active depth for methane oxidation. Compost biofilters consisted of 238-L barrels containing a 1:1 mixture (by volume) of compost to expanded polystyrene pellets. Two replicates of each type of biofilter were tested at an outdoor facility. Gas inflow consisted of an approximately 1:1 mixture (by volume) of CH4 and CO2. Methane output rates (J(out); g m(-2) day(-1)) were measured using the static chamber technique and the Pedersen et al. (2001) diffusion model. Methane oxidation rate (J(ox); g m(-2) day(-1)) and fraction of methane oxidized (f(ox)) were determined by mass balance. For methane inflow rates (J(in)) between 250 and 500 g m(-2) day(-1), the compost biofilter J(ox), 242 g m(-2) day(-1), was not significantly different (P = 0.0647) than the water-spreading biofilter J(ox), 203 g m(-2) day(-1); and the compost f(ox), 69%, was not significantly different (P = 0.7354) than water-spreading f(ox), 63%. The water-spreading biofilter was shown to generally perform as well as the compost biofilter, and it may be easier to implement at a landfill and require less maintenance.

  10. Dolomite limits acidification of a biofilter degrading dimethyl sulphide

    PubMed

    Smet; Van Langenhove H; Philips

    1999-01-01

    The applicability of dolomite particles to control acidification in a Hyphomicrobium MS3 inoculated biofilter removing dimethyl sulphide (Me2S) was studied. While direct inoculation of the dolomite particles with the liquid microbial culture was not successful, start-up of Me2S-degradation in the biofilter was observed when the dolomite particles were mixed with 33% (wt/wt) of Hyphomicrobium MS3-inoculated compost or wood bark material. Under optimal conditions, an elimination capacity (EC) of 1680 g Me2S m(-3) d(-1) was obtained for the compost/dolomite biofilter. Contrary to a wood bark or compost biofilter, no reduction in activity due to acidification was observed in these biofilters over a 235 day period because of the micro environment neutralisation of the microbial metabolite H2SO4 with the carbonate in the dolomite material. However, performance of the biofilter decreased when the moisture content of the mixed compost/dolomite material dropped below 15%. Next to this, nutrient limitation resulted in a gradual decrease of the EC and supplementation of a nitrogen source was a prerequisite to obtain a long-term high EC (> 250 g Me2S m(-3) d(-1)) for Me2S. In relation to this nitrogen supplementation, it was observed that stable ECs for Me2S were obtained when this nutrient was dosed to the biofilter at a Me2S-C/NH4Cl-N ratio of about 10.

  11. Biomass and microbial activity in a biofilter during backwashing*

    PubMed Central

    Bai, Yu; Zhang, Jie; Li, Yi-fan; Gao, Yu-nan; Li, Yong

    2005-01-01

    Biomass and microbial activity in backwashing processes of a biofilter for tertiary treatment were investigated. The microbial groups revealed new distribution along the biofilter depth after low flow rate backwashing for a short time. Then the start-up process was accelerated by backwashing. The biomass profile and microbial activity profile both varying with depth before and after backwashing, can be mathematically described by quadratic equations. Using the profiles, the difference of oxygen demand can be calculated to determine the airflow rate during backwashing. Combined with the difference between biofilters and rapid gravity filters, analysis of biomass and microbial activity can determine more accurately the required airflow rate during backwashing. PMID:15822159

  12. Performance and Biofilm Activity of Nitrifying Biofilters Removing Trihalomethanes

    EPA Science Inventory

    Nitrifying biofilters seeded with three different mixed-culture sources degraded trichloromethane (TCM) and dibromochloromethane (DBCM). In addition, resuspended biofilm degraded TCM, bromododichloromethane (BDCM), DBCM, and tribromomethane (TBM) in backwash batch kinetic tests,...

  13. Performance and Biofilm Activity of Nitrifying Biofilters Removing Trihalomethanes

    EPA Science Inventory

    Nitrifying biofilters seeded with three different mixed-culture sources degraded trichloromethane (TCM) and dibromochloromethane (DBCM). In addition, resuspended biofilm degraded TCM, bromododichloromethane (BDCM), DBCM, and tribromomethane (TBM) in backwash batch kinetic tests,...

  14. Simulation of Biomass Accumulation Pattern in Vapor-Phase Biofilters

    PubMed Central

    Xi, Jin-Ying; Hu, Hong-Ying; Zhang, Xian

    2012-01-01

    Abstract Existence of inert biomass and its impact on biomass accumulation patterns and biofilter performance were investigated. Four biofilters were set up in parallel to treat gaseous toluene. Each biofilter operated under different inlet toluene loadings for 100 days. Two microbial growth models, one with an inert biomass assumption and the other without, were established and compared. Results from the model with the inert biomass assumption showed better agreement with the experimental data than those based on the model without the inert biomass assumption thus verifying that inert biomass accumulation cannot be ignored in the long-term operation of biofilters. According to the model with an inert biomass assumption, the ratio of active biomass to total biomass will decrease and the inert biomass will become dominant in total biomass after a period of time. Filter bed structure simulation results showed that the void fraction is more sensitive to biomass accumulation than the specific surface area. The final void fraction of the biofilters with the highest inlet toluene loading is only 67% of its initial level while the final specific surface area is 82%. Identification and quantification of inert biomass will give a better understanding of biomass accumulation in biofilters and will result in a more exact simulation of biomass change during long-term operations. Results also indicate that an ideal biomass control technique should be able to remove most inert biomass while simultaneously preserving as much active biomass as possible. PMID:22693411

  15. Thermophilic biofilter for SO2 removal: performance and microbial characteristics.

    PubMed

    Zhang, Jingying; Li, Lin; Liu, Junxin

    2015-03-01

    A bench-scale thermophilic biofilter was applied to remove SO2 at 60°C in the present study. The SO2 concentration in the inlet stream ranged from 100mg/m(3) to 200mg/m(3). An average SO2 removal efficiency of 93.10% was achieved after developing acclimated organisms that can degrade SO2. The thermophilic biofilter effectively reduced SO2, with a maximum elimination capacity of 50.67g/m(3)/h at a loading rate of 51.44g/m(3)/h. Removal efficiency of the thermophilic biofilter was largely influenced by the water containing rate of the packing materials. The SO2 transfer in the biofilter included adsorption by the packing materials, dissolution in liquid, and microbial degradation. The main product of SO2 degradation was SO4(2-). The temporal shifts in the bacterial community that formed in the biofilter were determined through polymerase chain reaction-denaturing gradient gel electrophoresis and DNA sequence analysis. These shifts revealed a correlation between biofilter performance and bacterial community structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Microbial oxidation of methane from old landfills in biofilters

    SciTech Connect

    Streese, J.; Stegmann, R

    2003-07-01

    Landfill gas emissions are among the largest sources of the greenhouse gas methane. For this reason, the possibilities of microbial methane degradation in biofilters were investigated. Different filter materials were tested in two experimental plants, a bench-scale plant (total filter volume 51 l) and a pilot plant (total filter volume 4 m{sup 3}). Three months after the beginning of the experiment, very high degradation rates of up to 63 g CH{sub 4}/(m{sup 3}h) were observed in the bench-scale plant at mean methane concentrations of 2.5% v/v and with fine-grained compost as biofilter material. However, the degradation rates of the compost biofilter decreased in the fifth month of the experiment, probably due to the accumulation of exopolymeric substances formed by the microorganisms. A mixture of compost, peat, and wood fibers showed stable and satisfactory degradation rates around 20 g/(m{sup 3}h) at mean concentrations of 3% v/v over a period of one year. In this material, the wood fibers served as a structural material and prevented clogging of the biofilter. Extrapolation of the experimental data indicates that biofilters for methane oxidation have to be at least 100 times the volume of biofilters for odor control to obtain the same cleaning efficiency per unit volume flow of feed gas.

  17. Ammonia-Oxidizing Bacteria in Biofilters Removing Trihalomethanes Are Related to Nitrosomonas oligotropha

    EPA Science Inventory

    Nitrifying biofilters degrading the four regulated trihalomethanes (THMs) trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and tribromomethane (TBM) -were analyzed for the presence and activity of ammonia-oxidizing bacteria (AOB). Biofilter perfor...

  18. An improved biofilter to control the dissolved organic nitrogen concentration during drinking water treatment.

    PubMed

    Zhang, Huining; Gu, Li; Liu, Bing; Gan, Huihui; Zhang, Kefeng; Jin, Huixia; Yu, Xin

    2016-09-01

    Dissolved organic nitrogen (DON) is a key precursor of numerous disinfection by-products (DBPs), especially nitrogenous DBPs (N-DBPs) formed during disinfection in drinking water treatment. To effectively control DBPs, reduction of the DON concentration before the disinfection process is critical. Traditional biofilters can increase the DON concentration in the effluent, so an improved biofilter is needed. In this study, an improved biofilter was set up with two-layer columns using activated carbon and quartz sand under different influent patterns. Compared with the single-layer filter, the two-layer biofilter controlled the DON concentration more efficiently. The two-point influent biofilter controlled the DON concentration more effectively than the single-point influent biofilter. The improved biofilter resulted in an environment (including matrix, DO, and pH) suitable for microbial growth. Along the depth of the biofilter column, the environment affected the microbial biomass and microbial activity and thus affected the DON concentration.

  19. Ammonia-Oxidizing Bacteria in Biofilters Removing Trihalomethanes Are Related to Nitrosomonas oligotropha

    EPA Science Inventory

    Nitrifying biofilters degrading the four regulated trihalomethanes (THMs) trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and tribromomethane (TBM) -were analyzed for the presence and activity of ammonia-oxidizing bacteria (AOB). Biofilter perfor...

  20. The behavior of biofilters under inhibiting conditions related to the offgas

    SciTech Connect

    Nieuwland, J.C.W.; Hoek-Mann, A.; McGrath, M.; Kampeter, S.; Dijkhuis, E.

    1999-07-01

    There have been numerous cases in which biofilters have been disappointing in their ability to meet expectations on performance. Often this is related to bad biofilter design. However, in some cases these failures are related to problems of biological origin. This article presents an overview of the different mechanisms for biological inhibition in biofilters related to experiences with full scale biofilters in the industry. Recommendations for overcoming four of the major biological inhibitions are presented.

  1. Surrogates for herbicide removal in stormwater biofilters.

    PubMed

    Zhang, Kefeng; Deletic, Ana; Page, Declan; McCarthy, David T

    2015-09-15

    Real time monitoring of suitable surrogate parameters are critical to the validation of any water treatment processes, and is of particularly high importance for validation of natural stormwater treatment systems. In this study, potential surrogates for herbicide removal in stormwater biofilters (also known as stormwater bio-retention or rain-gardens) were assessed using field challenge tests and matched laboratory column experiments. Differential UV absorbance at 254mn (ΔUVA254), total phosphorus (ΔTP), dissolved phosphorus (ΔDP), total nitrogen (ΔTN), ammonia (ΔNH3), nitrate and nitrite (ΔNO3+NO2), dissolved organic carbon (ΔDOC) and total suspended solids (ΔTSS) were compared with glyphosate, atrazine, simazine and prometryn removal rates. The influence of different challenge conditions on the performance of each surrogate was studied. Differential TP was significantly and linearly related to glyphosate reduction (R(2) = 0.75-0.98, P < 0.01), while ΔTP and ΔUVA254 were linearly correlated (R(2) = 0.44-0.84, P < 0.05) to the reduction of triazines (atrazine, simazine and prometryn) in both field and laboratory tests. The performance of ΔTP and ΔUVA254 as surrogates for herbicides were reliable under normal and challenge dry conditions, but weaker correlations were observed under challenge wet conditions. Of those tested, ΔTP is the most promising surrogate for glyphosate removal and ΔUVA254 is a suitable surrogate for triazines removal in stormwater biofilters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Gradient packing bed bio-filter for landfill methane mitigation.

    PubMed

    Obulisamy, Parthiba Karthikeyan; Sim Yan May, Jane; Rajasekar, Balasubramanian

    2016-10-01

    We assessed the suitability of various biogenic materials for development of a gradient packed bed bio-filter to mitigate the methane (CH4) emission from landfills. Five different biogenic materials (windrow compost-WC; vermicompost-VC; landfill top cover-LTC; landfill bottom soil-LBS; and river soil sediment-SS) were screened. Among these materials, the VC showed a better CH4 oxidation potential (MOP) of 12.6μg CH4 gdw(-1)h(-1). Subsequently, the VC was used as a packing material along with wood chips in proto-type bio-filters. Wood chips were mixed at 5-15% to form three distinct gradients in a test bio-filter. Under the three different CH4 loading rates of 33, 44 and 55 gCH4 m(-3)h(-1), the achieved MOPs were 31, 41, and 47gCH4 m(-3)h(-1), respectively. The gradient packed bed bio-filter is effective for landfill CH4 mitigation than the conventional bio-filter as the latter shows gas channeling effects with poor MOPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. The effects of the flow pattern on organic oxidation and nitrification in aerated submerged biofilters.

    PubMed

    Chiou, R J; Ouyang, C F; Lin, C T

    2001-06-01

    Previous research has shown that a submerged biofilter is effective in removing organic matter and total organic nitrogen. Upflow and downflow biofilters were set up to investigate the different oxidative efficiencies on organic matter and ammonia nitrogen of different biofilter positions and to compare the biological activities of the upflow and downflow patterns. A comparison of the operational characteristics of the two types of biofilters is discussed. The main COD removal zone is 0-20 cm in the upflow biofilter, but in the downflow biofilter it occurs in the submerged zone. The nitrification process is dependent on the HRT and the residual COD. In the downflow biofilter, the efficiency of the nitrification increases with the HRT. The growth of nitrifying bacteria has a tendency to take place in higher zones in the downflow biofilter, especially for a longer HRT. Batch tests measured the biological activity of heterotrophs and nitrifying autotrophs with decomposition rates. In the upflow biofilter, the nitrification rates increased while the COD oxidative rates decreased with the height of the biofilter, so the effect of the HRT on the activity of the nitrifying autotrophs is significant. However, in the down biofilter, the activity of the nitrifying autotrophs was similar at different heights in the same HRT runs with the maximum nitrifying autotrophs activity being at an HRT of 6 hours.

  4. Numerical simulation on the reduction of flow heterogeneity in the biofilter media

    NASA Astrophysics Data System (ADS)

    Yan, Weiwei; Liu, Xingli; Wu, Jie; Wei, Yikun; Xu, Peng

    2016-02-01

    The biofilters are the ideal solutions for the biological treatment of air pollutants. However, there exists strong flow heterogeneity in porous media that degrades the removal efficiency of biofilters. Thus, the effects of Darcy number, Reynolds number and porosity of porous media on the reduction of flow heterogeneity in three biofilter models were numerically studied by the lattice Boltzmann method. The simulation results lead to three conclusions: (1) The Darcy number has dominant influence on the flow heterogeneity in the biofilters. The reduction of flow heterogeneity can be realized by designing a comparatively low Darcy number. (2) The Reynolds number has obvious effect on the flow heterogeneity in the biofilters. However, the reduction of flow heterogeneity cannot be effectively established by regulating the Reynolds number. (3) The property of porous media greatly influences the flow heterogeneity in the biofilters. The present results are helpful for the optimized design of practical biofilter models.

  5. Biodegradation of vapor phase trichloroethylene (TCE) in compost packed biofilters

    SciTech Connect

    Sukesan, S.; Watwood, M.E.

    1996-10-01

    Batch and column scale biofiltration experiments were performed to measure biodegradation of gaseous trichloroethylene (TCE) in finished compost. Compost was amended with hydrocarbon gas (methane or propane) as primary substrate to support microorganisms capable of cometabolic TCE degradation. In column biofilter experiments hydrocarbon utilization was observed within 10-15 days; gaseous TCE (50 ppmv) was then introduced continuously into the biofilter at approximately 1 L min{sup -1}. Columns supplied with 0.5% v/v methane removed 73% TCE after 8 days of continuous column operation, whereas amendment with 0.25% v/v methane corresponded with TCE removal of 93%, which was observed after 1.5 h of column operation. Similar results were obtained for propane amendment. Biofilters without hydrocarbon amendment exhibited no TCE biodegradation over 35 days. These results, analyzed together with those obtained in batch experiments, indicate that hydrocarbon identity and concentration and other related parameters influence the extent of ICE breakdown.

  6. Reverse-flow strategy in biofilters treating CS₂ emissions.

    PubMed

    Rojo, Naiara; Gallastegui, Gorka; Gurtubay, Luis; Barona, Astrid; Elías, Ana

    2013-04-01

    The bacteriostatic properties of carbon disulphide (CS₂) hamper its biodegradation in conventional biofilters. The response of four biofilters operating in downflow mode and reverse-flow mode was compared in a laboratory-scale plant treating CS₂ under sudden short-term changes in operating conditions. A process shutdown for 24 h, an inlet concentration increase and an interruption of the inlet air humidification for 48 h at an empty bed residence time (EBRT) of 240 s did not impact significantly on biodegradation performance, regardless of flow mode. Nevertheless, a reduction in the EBRT to 60 s resulted in a significant decrease in removal efficiency in all the biofilters. The CS₂ degradation profile showed that the reverse-flow mode strategy rendered a more homogenous distribution of biomass along the bed height. The benefits of the reverse-flow mode were demonstrated even when the unidirectional flow mode was re-established.

  7. Full-scale biofilter reduction efficiencies assessed using portable 24-hour sampling units.

    PubMed

    Akdeniz, Neslihan; Janni, Kevin A

    2012-02-01

    Portable 24-hr sampling units were used to collect air samples from eight biofilters on four animal feeding operations. The biofilters were located on a dairy, a swine nursery, and two swine finishing farms. Biofilter media characteristics (age, porosity, density, particle size, water absorption capacity, pressure drop) and ammonia (NH3), hydrogen sulfide (H2S), sulfur dioxide (SO2), methane (CH4), and nitrous oxide (N2O) reduction efficiencies of the biofilters were assessed. The deep bed biofilters at the dairy farm, which were in use for a few months, had the most porous media and lowest unit pressure drops. The average media porosity and density were 75% and 180 kg/m3, respectively. Reduction efficiencies of H2S and NH3 (biofilter 1: 64% NH3, 76% H2S; biofilter 2: 53% NH3, 85% H2S) were close to those reported for pilot-scale biofilters. No N2O production was measured at the dairy farm. The highest H2S, SO2, NH3, and CH4 reduction efficiencies were measured from a flat-bed biofilter at the swine nursery farm. However, the highest N2O generation (29.2%) was also measured from this biofilter. This flat-bed biofilter media was dense and had the lowest porosity. A garden sprinkler was used to add water to this biofilter, which may have filled media pores and caused N2O production under anaerobic conditions. Concentrations of H2S and NH3 were determined using the portable 24-hr sampling units and compared to ones measured with a semicontinuous gas sampling system at one farm. Flat-bed biofilters at the swine finishing farms also produced low amounts of N2O. The N2O production rate of the newer media (2 years old) with higher porosity was lower than that of older media (3 years old) (P = 0.042).

  8. Performance and biofilm activity of nitrifying biofilters removing trihalomethanes.

    PubMed

    Wahman, David G; Katz, Lynn E; Speitel, Gerald E

    2011-02-01

    Nitrifying biofilters seeded with three different mixed-culture sources removed trichloromethane (TCM) and dibromochloromethane (DBCM) with removals reaching 18% for TCM and 75% for DBCM. In addition, resuspended biofilm removed TCM, bromodichloromethane (BDCM), DBCM, and tribromomethane (TBM) in backwash batch kinetic tests, demonstrating that the biofilters contained organisms capable of biotransforming the four regulated trihalomethanes (THMs) commonly found in treated drinking water. Upon the initial and subsequent increased TCM addition, total ammonia nitrogen (TOTNH(3)) removal decreased and then reestablished, indicating an adjustment by the biofilm bacteria. In addition, changes in DBCM removal indicated a change in activity related to DBCM. The backwash batch kinetic tests provided a useful tool to evaluate the biofilm's bacteria. Based on these experiments, the biofilters contained bacteria with similar THM removal kinetics to those seen in previous batch kinetic experiments. Overall, performance or selection does not seem based specifically on nutrients, source water, or source cultures and most likely results from THM product toxicity, and the use of GAC media appeared to offer benefits over anthracite for biofilter stability and long-term performance, although the reasons for this advantage are not apparent based on research to date.

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

    PubMed

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

    2015-04-01

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

  10. Assessment of Biofilter Media Particle Sizes for Removing Ammonia

    USDA-ARS?s Scientific Manuscript database

    With increased concerns over odor and gas emissions from livestock production facilities more efficient technologies of air pollution control are needed to mitigate the deleterious effects of air contaminants. Gas-phase biofilters for treating contaminant gases from poultry and livestock operations ...

  11. ASSESSMENT OF BIOFILTER MEDIA PARTICLE SIZES FOR REMOVING AMMONIA

    USDA-ARS?s Scientific Manuscript database

    With increased concerns over odor and gas emissions from livestock production facilities more efficient technologies of air pollution control are needed to mitigate the deleterious effects of air contaminants. Gas-phase biofilters for treating contaminant gases from poultry and livestock operations ...

  12. DEVELOPMENT OF AEROBIC BIOFILTER DESIGN CRITERIA FOR TREATING VOCS

    EPA Science Inventory

    This paper reports preliminary results on the use of trickle bed biofilters with monolithic ceramic channelized microbial support structures for the treatment of VOCs typical of landfill leachate stripping. Toluene was used for the purpose of characterizing the trickle bed biofi...

  13. DEVELOPMENT OF AEROBIC BIOFILTER DESIGN CRITERIA FOR TREATING VOCS

    EPA Science Inventory

    This paper reports preliminary results on the use of trickle bed biofilters with monolithic ceramic channelized microbial support structures for the treatment of VOCs typical of landfill leachate stripping. Toluene was used for the purpose of characterizing the trickle bed biofi...

  14. Ethylene Removal by a Biofilter with Immobilized Bacteria

    PubMed Central

    Elsgaard, Lars

    1998-01-01

    A biofilter which eliminated ethylene (C2H4) from the high parts-per-million range to levels near the limit for plant hormonal activity (0.01 to 0.1 ppm) was developed. Isolated ethylene-oxidizing bacteria were immobilized on peat-soil in a biofilter (687 cm3) and subjected to an atmospheric gas flow (73.3 ml min−1) with 2 or 117 ppm of C2H4. Ethylene was eliminated to a minimum level of 0.017 ppm after operation with 2.05 ppm of C2H4 for 16 days. Also, the inlet C2H4 concentration of 117 ppm was reduced to <0.04 ppm. During operation with 2 and 117 ppm of C2H4, an increase in the C2H4 removal rate was observed, which was attributed to proliferation of the immobilized bacteria, notably in the first 0- to 5-cm segment of the biofilter. The maximal C2H4 elimination capacity of the biofilter was 21 g of C2H4 m−3 day−1 during operation with 117 ppm of C2H4 in the inlet gas. However, for the first 0- to 5-cm segment of the biofilter, an elimination capacity of 146 g of C2H4 m−3 day−1 was calculated. Transition of the biofilter temperature from 21 to 10°C caused a 1.6-fold reduction in the C2H4 removal rate, which was reversed during operation for 18 days. Batch experiments with inoculated peat-soil demonstrated that C2H4 removal still occurred after storage at 2, 8, and 20°C for 2, 3, and 4 weeks. However, the C2H4 removal rate decreased with increasing storage time and was reduced by ca. 50% after storage for 2 weeks at all three temperatures. The biofilter could be a suitable tool for C2H4 removal in, e.g., horticultural storage facilities, since it (i) removed C2H4 to 0.017 ppm, (ii) had a good operational stability, and (iii) operated efficiently at 10°C. PMID:9797261

  15. Interaction of gaseous aromatic and aliphatic compounds in thermophilic biofilters.

    PubMed

    Hu, Qing-yuan; Wang, Can

    2015-12-30

    Two thermophilic biofilters were applied in treating a mixture of gaseous aromatic (benzene) and aliphatic compounds (hexane) to evaluate the interaction of the compounds. The performance of the biofilters was investigated in terms of removal efficiencies, elimination capacity, kinetic analysis, interaction indices, and microbial metabolic characteristics. Results showed that the removal performance of benzene was unaffected by the addition of hexane. The removal efficiencies of benzene were maintained at approximately 80% and the biodegradation rate constant was maintained at 120 h(-1). However, the removal efficiencies of hexane decreased significantly from 60% to 20% and the biodegradation rate constant exhibited a distinct decrease from 93.59 h(-1) to 56.32 h(-1). The interaction index of benzene with the addition of hexane was -0.029, which indicated that hexane had little effect on the degradation of benzene. By contrast, the interaction index of hexane by benzene was -0.557, which showed that benzene inhibited the degradation of hexane significantly. Similar conclusions were obtained about the substrate utilization. Moreover, the utilization degree of carbon sources and the microbial metabolic activities in the biofilter treating hexane were significantly improved with the addition of benzene, whereas the addition of hexane had a slight effect on the microbial communities in the biofilter treating benzene. Conclusions could be obtained that when mixtures of benzene and hexane were treated using biofilters, the degradation of benzene, which was more easily degradable, was dominant and unaffected; whereas the degradation of hexane, which was less easily degradable, was inhibited because of the changing of microbes. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Numerical simulation of air flow through a biofilter with heterogeneous porous media.

    PubMed

    Yan, Wei-Wei; Liu, Yang; Xu, You-Sheng; Yang, Xiang-Long

    2008-05-01

    Based on the ideal biofilter model, numerical simulation using lattice Boltzmann method is carried out to investigate the effect of Darcy number and porosity on removal efficiency of low headloss biofilter. The generalized Navier-Stokes model (Brinkman-Forchheimer-extended Darcy model) is applied making several assumptions. It is found that the Darcy number has determinant influence on the removal efficiency, and the effect of porosity on removal efficiency is very weak at lower Darcy numbers but very strong at higher Darcy numbers. It was found there was strong evidence of flow heterogeneity in the biofilter (Chitwood, D.E., Devinny, J.S., Reynolds Jr., F.E., 1999. Evaluation of a two-stage biofilter for treatment of POTW waste air. Environ. Prog. 18, 212-221). In this study we have found the biofilter performance can be improved by adjusting local Darcy number of the porous media in the biofilter.

  17. Biogeochemical analysis of hydrogen sulfide removal by a lava-rock packed biofilter.

    PubMed

    Li, Hebi; Lueking, Donald R; Mihelcic, James R; Peterson, Karl

    2005-01-01

    Although lava-rock-based biofilters have demonstrated their efficiencies for hydrogen sulfide (H2S) removal found in odorous air emissions, the biogeochemical basis for this removal is unclear. In this study, samples of lava rock and rinse water from biofilters at Cedar Rapids Water Pollution Control Facilities (Iowa) were used to study the structure and chemical composition of lava rock and to identify the predominant microorganism(s) present in lava-rock-based biofilters. It was found that iron, in the form of Fe2+ and Fe3+, was present in lava rock. Although literature suggests that Acidithiobacillus thiooxidans are primarily responsible for gaseous H2S removal in biofilters, our study showed that Acidithiobacillus ferrooxidans was the dominant microorganism in the lava-rock-based biofilters. A novel mechanism for H2S removal in a lava-rock-based biofilter is proposed based on the biogeochemical analysis of lava rock.

  18. Variations in dissolved organic nitrogen concentration in biofilters with different media during drinking water treatment.

    PubMed

    Zhang, Huining; Zhang, Kefeng; Jin, Huixia; Gu, Li; Yu, Xin

    2015-11-01

    Dissolved organic nitrogen (DON) is potential precursor of disinfection byproducts (DBPs), especially nitrogenous DBPs. In this study, we investigated the impact of biofilters on DON concentration changes in a drinking water plant. A small pilot plant was constructed next to a sedimentation tank in a drinking water plant and included activated carbon, quartz sand, anthracite, and ceramsite biofilters. As the biofilter layer depth increased, the DON concentration first decreased and then increased, and the variation in DON concentration differed among the biofilters. In the activated carbon biofilter, the DON concentration was reduced by the largest amount in the first part of the column and increased by the largest amount in the second part of the column. The biomass in the activated carbon filter was less than that in the quartz sand filter in the upper column. The heterotrophic bacterial proportion among bacterial flora in the activated carbon biofilter was the largest, which might be due to the significant reduction in DON in the first part of the column. Overall, the results indicate that the DON concentration in biofiltered water can be controlled via the selection of appropriate biofilter media. We propose that a two-layer biofilter with activated carbon in the upper layer and another media type in the lower layer could best reduce the DON concentration.

  19. Modelling and experimental investigation on the application of water super adsorbents in waste air biofilters.

    PubMed

    Danaee, Soroosh; Fazaelipoor, Mohammad Hassan; Gholami, Abdollah; Ataei, Seyed Ahmad; Afzali, Daryoush

    2015-01-01

    In this research work, a synthetic water super absorbent polymer was included in the bed of a perlite-based biofilter for the removal of ethanol from air. The performance of this biofilter was compared with the performance of a control perlite-based biofilter lacking the water super absorbent. With the empty bed residence time of 2 min, both biofilters were able to remove more than 90% of the entering pollutant with the concentration of 1 g /m3, when regular moistening was applied. After last irrigation on day 23, the performance of the control biofilter was unchanged until day 35. From day 36 onwards, the control biofilter lost its activity gradually and became totally inactive on day 45. The performance of the super absorbent containing biofilter, however, was unchanged until day 58 before starting to lose its activity. A mechanistic model was developed to describe the performance of a biofilter under drying effects. The model could predict the trends of experimental results reasonably well. The model was also applied to predict the trends of experimental data from a published paper on the removal of hexane in a perlite/super absorbent containing biofilter.

  20. Performance of low pH biofilters treating a paint solvent mixture: continuous and intermittent loading.

    PubMed

    Qi, Bing; Moe, William M

    2006-07-31

    Two biofilters packed with a reticulated polyurethane foam medium were inoculated with a compost-derived enrichment culture grown under acidic conditions (pH 3.0) and then operated over a period lasting 63 days. Both biofilters were supplied with a humidified gas stream containing a five-component mixture of acetone, methyl ethyl ketone, toluene, ethylbenzene, and p-xylene at a total VOC loading rate 80.3 gm(-3)h(-1) to simulate treatment of air emissions resulting from manufacture of reformulated paint. One biofilter was operated under continuous loading conditions and the other received intermittent loading with contaminants supplied only 8 h/day. Nutrient solution with pH 3.0 was supplied approximately once per week to provide nitrogen and other nutrients. Data are presented which demonstrate that undefined mixed cultures acclimated at low pH can successfully treat paint solvent mixtures in biofilters. The biofilter receiving continuous loading reached high overall removal efficiency (greater than 90% overall removal) 3 weeks after startup, and performance increased over time reaching overall removal in the range of 97-99% after 50 days. Performance of the intermittently loaded biofilter developed more slowly, requiring 6 weeks to stabilize at an overall removal efficiency in excess of 90%. In both biofilters, ketone components were more rapidly degraded than aromatic components, and removal of aromatic compounds was somewhat unstable even after 2 months of biofilter operation. Scanning electron microscopy (SEM) revealed that fungi dominated the microbial populations in both biofilters.

  1. Evaluation of a two-stage biofilter for treatment of POTW waste air

    SciTech Connect

    Chitwood, D.E.; Devinny, J.S.; Reynolds, F.E. Jr.

    1999-09-30

    Recent efforts have been made to reduce releases of air toxics and smog precursors from wastewater treatment plants. Hydrogen sulfide is commonly the primary odor and is an important target for removal. Its oxidation, however, generates sulfuric acid and sometimes elemental sulfur, which can create substantial operational problems for biofilters. Declining pH may inhibit the organisms that degrade compounds other than hydrogen sulfide and may hasten aging of organic biofilter media. A two-stage biofilter has been designed and installed at the Ohio Valley Sanitary District wastewater treatment plant. The first stage is an enclosed system with a medium of small, inert, porous stones. It is called an acid gas biofilter. The second stage is a section of a traditional open biofilter filled with wood chips. The acid gas biofilter effectively removed H{sub 2}S and volatile organic compounds while causing much lower headloss than traditional biofilters. However, considerable flow heterogeneity in both the acid gas biofilter and the wood chip biofilter was observed. The two-stage system presumably will have a longer bed life because the first stage bed is inert and because the second stage is protected from acidification by removal of H{sub 2}S in the first stage.

  2. Effects of addition of straw, chitin and manure to new or recycled biofilters on their pesticides retention and degradation properties.

    PubMed

    Genot, P; Van Huynh, N; Debongnie, Ph; Pussemier, L

    2002-01-01

    Pollution of surface and groundwater by pesticides is an increasing problem that needs to be addressed by the authorities as well as by the farmers themselves. Nowadays, some researchers are considering the numerous small spillages at the farm sites as a relevant entry route to be taken into account for predicting surface and groundwater pollution. In order to tackle this problem, several solutions exist for limiting the disposal of pesticide wastes into the environment. One such system is biopurification of farm wastes by biobed, biofilter or phytobac. In this study, the results of pesticides retention by biofilters under outdoor conditions are presented. The biofilters were filled with a mixture of a soil + peat constituent (25% by volume for each of them) and the rest (50%) with straw or with composted manure ot with chitin (in this later case at the rate of 5 g chitin per liter of substrate). The soil + peat constituent was made either of a material already challenged by pesticides (= recycled biofilters) or of untreated material (new biofilters). Selected pesticides (atrazine, carbofuran, chloridazon, chlortoluron, cyanazine, isoproturon and lenacil) were applied onto biofilters and the eluates were collected and analyzed. Two successive injections of pesticides into the biofilters were conducted. After the first pesticides application, the recycled biofilters made of soil + peat previously treated with pesticides had better retention and degradation rates than the new biofilters. Adding manure also improved these properties of biofilters. Columns made of unchallenged soil + peat and straw (new biofilters) were the least satisfactory: up to 25% of carbofuran were lost. Biofilters made of unchallenged soil + peat and chitin retained the least lenacil. Atrazine was the most retained by biofilters (either new or recycled) with added chitin. Cyanazine was almost absent in the percolates of all biofilters. After the second application of carbofuran and isoproturon

  3. Ultra-Violet Light/Ozone Treatment of a Sequentially Loaded and Regenerated Granular Activated Carbon Biofilter

    DTIC Science & Technology

    1997-08-01

    The research described herein has evaluated a UV/ozone in-situ regeneration treatment of sequentially loaded and regenerated GAC biofilters used for...including ultra-violet light (UV)/ozone treatment of sequentially loaded and regenerated GAC biofilters , (b) biofilter biofilm kinetics, and (c) UV/ozone...treatment of virgin and loaded GAC. The GAC biofilter was alternately exposed to a simulated waste air stream laden with MIBK for 24 hours, followed

  4. Ein Kredit für Weihnachtsbaumkugeln

    NASA Astrophysics Data System (ADS)

    Tutsch, Sina

    Eine Mathematikerin aus dem DFG-Forschungszentrum Matheon arbeitet an Methoden zur dreidimensionalen Visualisierung. Sie hat die Geschäftsidee, Weihnachtsbaumkugeln mit bewegten Hologrammen herzustellen, die sich individuell gestalten lassen, und plant eine Existenzgründung. Aus einem öffentlichen Förderprogramm erhält sie ein günstiges Darlehen in Höhe von 50 000 Euro. Für die Startphase ihres Unternehmens benötigt sie jedoch den vierfachen Betrag.

  5. Biofilter performance of pine nuggets and lava rock as media.

    PubMed

    Akdeniz, Neslihan; Janni, Kevin A; Salnikov, Ilya A

    2011-04-01

    Wood chips and bark mulch are commonly used biofilter media because they are generally locally available and inexpensive. Nevertheless, these organic materials degrade and require replacement every 2-5 years. In this study, airflow characteristics and gas reduction efficiencies of two alternative biofilter media (pine nuggets and lava rock) with high porosity and potentially longer service lives were evaluated at three empty bed contact times (1, 3, and 5s) and two moisture levels (82% and 90% relative humidity). The lava rock had a lower pressure drop across the media and maintained higher media depth. Gas reduction efficiencies were highest for lava rock at 5s empty bed contact time and 90% humidity. The reduction efficiencies at these conditions were 56%, 88%, 87%, 25%, and 0.7% for ammonia, hydrogen sulfide, total reduced sulfur, methane and nitrous oxide, respectively. Odor reduction up to 48% was observed but was not consistent.

  6. Restaurant emissions removal by a biofilter with immobilized bacteria*

    PubMed Central

    Miao, Jian-yu; Zheng, Lian-ying; Guo, Xiao-fen

    2005-01-01

    Pseudomonas sp. ZD8 isolated from contaminated soil was immobilized with platane wood chips to produce packing materials for a novel biofilter system utilized to control restaurant emissions. The effects of operational parameters including retention time, temperature, and inlet gas concentration on the removal efficiency and elimination capacity were evaluated. Criteria necessary for a scale-up design of the biofilter was established. High and satisfactory level of rapeseed oil smoke removal efficiency was maintained during operation and the optimal retention time was found to be 18 s corresponding to smoke removal efficiency greater than 97%. The optimal inlet rapeseed oil smoke loading was 120 mg/(m3·h) at the upper end of the linear correlation between inlet loading and elimination capacity. PMID:15822160

  7. A High Performance Biofilter for VOC Emission Control.

    PubMed

    Wu, G; Conti, B; Leroux, A; Brzezinski, R; Viel, G; Heitz, M

    1999-02-01

    Biofiltration is a cleaning technique for waste air contaminated with some organic compounds. The advantages of the conventional biofilter over other biological systems are a high-superficial area best suited for the treatment of some compounds with poor water solubility, ease of operation, and low operating costs. It has crucial disadvantages, however; for example, it is not suitable to treat waste gases with high VOC concentrations and it has poor control of reaction conditions. To improve on these problems and to build a high-performance biofilter, three structured peat media and two trickling systems have been introduced in this study. The influences of media size and composition have been investigated experimentally. Peat bead blended with 30% (w/w) certain mineral material with a good binding capacity has advantages over other packing materials, for example, suitable size to prevent blockage due to microbial growth, strong buffering capacity to neutralize acidic substances in the system, and a pH range of 7.0-7.2 suitable for the growth of bacteria. Dropwise trickling system offers an effective measure to easily control the moisture content of the bed and the reaction conditions (pH, nutrient) and to partially remove excess biomass produced during the metabolic processes of microorganisms. The influence of nutrient supplementation has also been investigated in this study, which has revealed that the biological system was in a condition of nutrient limitation instead of carbon limitation. The biofilters built in our laboratory were used to treat waste gas contaminated with toluene in a concentration range of 1 to 3.2 g/m(3) and at the specific gas flow rate of 24 to120 m(3)/m(2).hr. Under the conditions employed, a high elimination capacity (135 g/m(3).hr) was obtained in the biofilter packed with peat beads (blended with 30% of the mineral material), and no blockage problem was observed in an experimental period of 2-3 months.

  8. Removal of beta-pinene and limonene using compost biofilter.

    PubMed

    Viswanathan, S; Neerackal, G; Buyuksonmez, F

    2013-02-01

    Composting is widely used for the treatment of solid organic wastes; however emissions from composting are becoming a threat to humans due to the release of toxic volatile organic compounds (VOCs). VOCs from composting operations are characterized by high flow rates and, normally, low pollutant concentration. Typical VOCs include a large amount of terpenes (-65% of total VOCs). This study was to investigate the efficiency of biofiltration in controlling terpene emissions from composting operations using a laboratory-scale unit. The performance of a biofilter was investigated as a function of inlet flow rate, inlet concentration, and bed length/bed diameter (L/D) ratio of bed. At the lowest total inlet flow rate, removal efficiency of limonene and beta-pinene was more than 90%. With the decrease in inlet concentration and increase in L/D ratio, the removal efficiency was effectively increased. Removal efficiency of more than 85% for Limonene and 45% for beta-Pinene was attained at a loading rate of 55 g/m3-hr. The maximum elimination capacity was found for 109.7 g/m3-hr for limonene and 10.3 g/m3-hr for beta-pinene at a critical loading of 150.1 g/m3-hr Based on this study, the compost bed could function as a biofilter for controlling terpene odors during the composting process. The purpose of this research project is to investigate the efficiency of biofiltration in controlling limonene and beta-pinene emissions from composting operations using a laboratory scale. In addition, the performance of a biofilter as a function of inlet flow rate, inlet concentration, and L/D ratio of bed was evaluated. Establishing a nexus between the operational parameters and efficiency would be useful in design and operation of compost bed as a biofilter for controlling terpene odors during the composting process.

  9. [Mechanism of NH(4+)-N removal in drinking water biofilter].

    PubMed

    Liu, Bing; Fan, Hui; Yu, Guo-Zhong; Yu, Xin; Zhao, Cheng-Mei; Li, Qing-Fei; Zhang, Shu-Ting; Wei, Bo

    2012-07-01

    In order to explore the mechanism of NH(4+)-N removal in drinking water biofilter, water quality parameters, such as NH(4+)-N, NO(2-)-N, NO(3-)-N, total phosphorus, permanganate index, nitrogen gas, temperature and dissolved oxygen etc, were determined in the inflow and outflow of biofilter. Samples of granular activated carbon (GAC) at different height (0, 10, 20, 40, 60 cm) of the biofiter media were collected and analyzed for the bacterial community with molecular biology techniques. The bacterial diversity in the activated carbon biofilm sample was studied based on the phylogenetic analysis of sequences. The results showed that there were three stages according to the NH(4+)-N concentration in the influent. The "nitrogen loss" phenomenon (total inorganic nitrogen in the effluent was less than that in the influent) occurred at the first, second and third stages and the amount of nitrogen loss were 0.94, 0.32 and 0.15 mg x L(-1), respectively. The amount of nitrogen loss had a good positive correlation with the NH(4+)-N concentration in the influent, but not a linear relationship with the concentration of the permanganate index in the influent. The average concentrations of N2 increased gradually with the height of media in the biofilter, with values of 14.04 and 14.67 mg x L(-1) in the influent and the effluent, respectively. Based on the sequencing results, the ammonia-oxidizing bacteria (AOB) in the activated carbon biofilm were classified into three common genera: Nitrosococcus, Nitrosomonas and Nitrosospira. When the NH(4+)-N concentration in the influent was relatively high, the "nitrogen loss" phenomenon in biofilter was caused by the AOB.

  10. Evaluation of full-scale biofilter media performance

    SciTech Connect

    Cardenas-Gonzalez, B.; Ergas, S.J.; Switzenbaum, M.S.; Phillibert, N.

    1999-09-30

    The objective of this study was to characterize the key physical, chemical and biological properties of compost media from a full-scale biofiltration system used to control VOC emissions. Results of media characterization were used to assess the need for operational changes and media replacement. Biofilter media properties evaluated included: moisture content, pH, total organic carbon (TOC) and nitrogen content in water extracts and solid matrix, oxygen uptake rates, and microbial plate counts including total heterotrophs, oligotrophs, actinomycetes and fungi. Samples were taken from various locations and depths in the biofilter after three and five years of system operation. Media moisture content was highly variable, with samples from deeper in the bed dryer than surface samples. Low moisture contents were associated with low pH values and low oxygen uptake rates. Total organic carbon contents in water extracts were higher than typical biosolids compost in samples near the inlet to the biofilter, possibly due to extracellular polysaccharides. After five years of use, total nitrogen and organic carbon contents in the solid matrix did not significantly differ from initial levels or those in typical biosolids compost.

  11. Preliminary stabilisation of stormwater biofilters and loss of filter material.

    PubMed

    Subramaniam, D N; Mather, P B

    Stabilisation affects performance of stormwater biofilters operating under intermittent wetting and drying, mainly due to wash-off of filter material. Understanding the dynamics of solids wash-off is crucial in designing stormwater biofilters. The current study analysed the dynamics of solids wash-off in stormwater biofilters and quantified the loss of solids from the filter. Four Perspex™ bioretention columns (94 mm internal diameter) were fabricated with a filter layer that contained 8% organic material and were fed with tap water with different numbers of antecedent dry days (0-40 day) at 100 mL/min. Samples were collected from the outflow and tested for particle size distribution and total solids and turbidity. Solids of particle size less than 50 microns were washed off from the filter during the stabilisation period, indicating that no sand particles were washed off. The very first event after commissioning the filter resulted in the highest wash-off of solids (approximately 75 g of fines) while a significant drop in wash-off followed from the second event. An empirical model fitted to the data showed that preliminary stabilisation of a filter occurs in the first three events, during which almost 25% of fines are lost from the filter.

  12. Livestock air treatment using PVA-coated powdered activated carbon biofilter

    USDA-ARS?s Scientific Manuscript database

    The efficacy of polyvinyl alcohol (PVA) biofilters was studied using bench-scale biofilters and air from aerobically-treated swine manure. The PVA-coated powdered activated carbon particles showed excellent properties as a biofiltration medium: water holding capacity of 1.39 g H2O/g-dry PVA; wet por...

  13. Ammonia-Oxidizing Bacteria in Biofilters Removing Trihalomethanes Are Related to Nitrosomonas oligotropha ▿

    PubMed Central

    Wahman, David G.; Kirisits, Mary Jo; Katz, Lynn E.; Speitel, Gerald E.

    2011-01-01

    Ammonia-oxidizing bacteria (AOB) in nitrifying biofilters degrading four regulated trihalomethanes—trichloromethane, bromodichloromethane, dibromochloromethane, and tribromomethane—were related to Nitrosomonas oligotropha. N. oligotropha is associated with chloraminated drinking water systems, and its presence in the biofilters might indicate that trihalomethane tolerance is another reason that this bacterium is dominant in chloraminated systems. PMID:21278264

  14. Effects of adsorptive properties of biofilter packing materials on toluene removal.

    PubMed

    Oh, Dong Ik; Song, Jihyeon; Hwang, Sun Jin; Kim, Jae Young

    2009-10-15

    Various adsorptive materials, including granular activated carbon (GAC) and ground tire rubber (GTR), were mixed with compost in biofilters used for treating gaseous toluene, and the effects of the mixtures on the stability of biofilter performance were investigated. A transient loading test demonstrated that a sudden increase in inlet toluene loading was effectively attenuated in the compost/GAC biofilter, which was the most significant advantage of adding adsorptive materials to the biofilter packing media. Under steady conditions with inlet toluene loading rates of 18.8 and 37.5 g/m(3)/h, both the compost and the compost/GAC biofilters achieved overall toluene removal efficiencies greater than 99%. In the compost/GAC mixture, however, biodegradation activity declined as the GAC mass fraction increased. Because of the low water-holding capacity of GTR, the compost/ground tire mixture did not show a significant improvement in toluene removal efficiency throughout the entire operational period. Furthermore, nitrogen limitations affected system performance in all the biofilters, but an external nitrogen supply resulted in the recovery of the toluene removal efficiency only in the compost biofilter during the test periods. Consequently, the introduction of excessive adsorptive materials was unfavorable for long-term performance, suggesting that the mass ratio of the adsorptive materials in such mixtures should be carefully selected to achieve high and steady biofilter performance.

  15. Phosphorus removal in a sulfur-limestone autotrophic denitrification (SLAD) biofilter.

    PubMed

    Li, Ruihua; Yuan, Yulin; Zhan, Xinmin; Liu, Bo

    2014-01-01

    The sulfur-limestone autotrophic denitrification (SLAD) biofilter was able to remove phosphorous from wastewater during autotrophic denitrification. Parameters influencing autotrophic denitrification in the SLAD biofilter, such as hydraulic retention time (HRT), influent nitrate (NO3(-)), and influent PO4(3-) concentrations, had significant effects on P removal. P removal was well correlated with total oxidized nitrogen (TON) removed in the SLAD biofilter; the more TON removed, the more efficient P removal was achieved. When treating the synthetic wastewater containing NO3(-)-N of 30 mg L(-1) and PO4(3-)-P of 15 mg L(-1), the SLAD biofilter removed phosphorus of 45% when the HRT was 6 h, in addition with TN removal of nearly 100%. The optimal phosphorus removal in the SLAD biofilter was around 60%. For the synthetic wastewater containing a PO4(3-)-P concentration of 15 mg L(-1), the main mechanism of phosphorus removal was the formation of calcium phosphate precipitates.

  16. Microbial Community in a Biofilter for Removal of Low Load Nitrobenzene Waste Gas.

    PubMed

    Zhai, Jian; Wang, Zhu; Shi, Peng; Long, Chao

    2017-01-01

    To improve biofilter performance, the microbial community of a biofilter must be clearly defined. In this study, the performance of a lab-scale polyurethane biofilter for treating waste gas with low loads of nitrobenzene (NB) (< 20 g m-3 h-1) was investigated when using different empty bed residence times (EBRT) (64, 55.4 and 34 s, respectively). In addition, the variations of the bacterial community in the biofilm on the longitudinal distribution of the biofilters were analysed by using Illumina MiSeq high-throughput sequencing. The results showed that NB waste gas was successfully degraded in the biofilter. High-throughput sequencing data suggested that the phylum Actinobacteria and genus Rhodococcus played important roles in the degradation of NB. The variations of the microbial community were attributed to the different intermediate degradation products of NB in each layer. The strains identified in this study were potential candidates for purifying waste gas effluents containing NB.

  17. Biological treatment and modeling aspect of BTEX abatement process in a biofilter.

    PubMed

    Rahul; Mathur, Anil Kumar; Balomajumder, Chandrajit

    2013-08-01

    In the present work, a laboratory scale corn-cob based biofilter inoculated with Bacillus sphaericus (MTCC 8103) was used for degradation of BTEX for a period of 86 days. The overall performance of a biofilter evaluated in terms of its elimination capacity by using 3-D mesh technique. Maximum removal efficiency was found more than 96.43% for all four compounds in each phase of experiments. A maximum elimination capacity (EC) of 60.89 gm(-3)h(-1) of the biofilter was obtained at inlet BTEX load of 63.14 gm(-3)h(-1). The follow-up of carbon dioxide concentration profile through the biofilter revealed that the mass ratio of carbon dioxide produced to the BTEX removed was approximately 2.2, which confirms complete degradation of BTEX. Moreover, BTEX concentration profile along the biofilter depth bed also determined by convection-diffusion reactor (CDR) model. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Microbial Community in a Biofilter for Removal of Low Load Nitrobenzene Waste Gas

    PubMed Central

    Zhai, Jian; Wang, Zhu; Shi, Peng; Long, Chao

    2017-01-01

    To improve biofilter performance, the microbial community of a biofilter must be clearly defined. In this study, the performance of a lab-scale polyurethane biofilter for treating waste gas with low loads of nitrobenzene (NB) (< 20 g m-3 h-1) was investigated when using different empty bed residence times (EBRT) (64, 55.4 and 34 s, respectively). In addition, the variations of the bacterial community in the biofilm on the longitudinal distribution of the biofilters were analysed by using Illumina MiSeq high-throughput sequencing. The results showed that NB waste gas was successfully degraded in the biofilter. High-throughput sequencing data suggested that the phylum Actinobacteria and genus Rhodococcus played important roles in the degradation of NB. The variations of the microbial community were attributed to the different intermediate degradation products of NB in each layer. The strains identified in this study were potential candidates for purifying waste gas effluents containing NB. PMID:28114416

  19. Effect of bed medium moisture on {alpha}-pinene removal by biofilters

    SciTech Connect

    Lee, B.D.; Apel, W.A.; Cook, L.L.; Nichols, K.M.

    1996-12-31

    In this study, laboratory scale continuous flow bioifilters were used to determine the effect of bed medium moisture on biofilter performance when treating off-gases containing {alpha}-pinene. Biofilters were packed using a proprietary wood waste bed medium and were operated at a flow rate of 700 ml of air per min, yielding an empty bed residence time of 2 minutes. For the bed medium moisture levels tested, a biofilter bed held at 100% moisture on a dry weight basis demonstrated the best overall {alpha}-pinene removal results. Volumetric productivity and percent removal were higher, while the time to reach maximum removal efficiency was decreased compared to biofilters operated at 40, 60 and 80% bed medium moisture. Results indicate that control of moisture in a biofilter is important for maximum removal of {alpha}-pinene.

  20. EIN Software Catalog; Entries, Volume III.

    ERIC Educational Resources Information Center

    Interuniversity Communications Council (EDUCOM), Boston, MA.

    The EIN (Educational Information Network) is a non-profit operation which coordinates the sharing of educational computing resources. It is administered by EDUCOM and funded jointly by the U. S. Office of Education and the National Science Foundation. EIN maintains a group of contact personnel at member institutions to serve as a liaison between…

  1. EIN Software Catalog; Entries, Volume I.

    ERIC Educational Resources Information Center

    Interuniversity Communications Council (EDUCOM), Boston, MA.

    The EIN (Educational Information Network) is a non-profit operation which coordinates the sharing of educational computing resources. It is administered by EDUCOM and funded by the U. S. Office of Education and the National Science Foundation. EIN maintains a group of contact personnel at member institutions to serve as a liaison between the…

  2. EIN Software Catalog; Entries, Volume II.

    ERIC Educational Resources Information Center

    Interuniversity Communications Council (EDUCOM), Boston, MA.

    The EIN (Educational Information Network) is a non-profit operation which coordinates the sharing of educational computing resources. It is administered by EDUCOM and funded jointly by the U. S. Office of Education and the National Science Foundation. EIN maintains a group of contact personnel at member institutions to serve as a liaison between…

  3. Bench-scale biofilter for removing ammonia from poultry house exhaust.

    PubMed

    Shah, S B; Basden, T J; Bhumbla, D K

    2003-01-01

    A bench-scale biofilter was evaluated for removing ammonia (NH3) from poultry house exhaust. The biofilter system was equipped with a compost filter to remove NH3 and calcium oxide (CaO) filter to remove carbon dioxide (CO2). Removal of NH3 and CO2 from poultry house exhaust could allow treated air with residual heat to be recirculated back into the poultry house to conserve energy during winter months. Apart from its use as a plant nutrient, NH3 removal from poultry house exhaust could lessen the adverse environmental impacts of NH3 emissions. Ammonia and CO2 were measured daily with gas detector tubes while temperatures in the poultry pen and compost filter were monitored to evaluate the thermal impact of the biofilter on treated air. During the first 37 days of the 54-day study, exhaust air from 33 birds housed in a pen was treated in the biofilter; for the final 17 days, NH3-laden exhaust, obtained by applying urea to the empty pen was treated in the biofilter. The biofilter system provided near-complete attenuation of a maximum short-term NH3 concentration of 73 ppm. During the last 17 days, with a mean influent NH3 concentration of 26 ppm, the biofilter provided 97% attenuation. The CaO filter was effective in attenuating CO2. Compared with a biofilter sized only for NH3 removal, an oversized biofilter would be required to provide supplemental heat to the treated air through exothermic biochemical reactions in the compost. The biofilter could conserve energy in poultry production and capture NH3 for use as plant nutrient. Based on this study, a house for 27,000 broilers would require a compost filter with a volume of approximately 34 m3.

  4. The effects of a lower irrigation system on pollutant removal and on the microflora of a biofilter.

    PubMed

    Sakuma, Takeyuki; Hattori, Toshihiro; Deshusses, Marc A

    2009-05-01

    Moisture control is one the most important parameters in biofilters for air pollution control. Biofilters tend to experience drying at the air inlet port, which causes decreased pollutant removal over time. In this study, the installation of an irrigation system within the lower part of the biofilter bed was proposed, and its effect was quantified in a laboratory scale biofilter operated side by side with a control biofilter. The removal of toluene vapours at short gas residence time (13.5 s) served as a model system. The results showed that the rate of toluene elimination in the biofilter with the lower irrigation system was 1.2-1.7 times greater than the rate of toluene elimination in the control biofilter. At the completion of the two-month experiment, a detailed examination was conducted of the packing materials with the immobilized pollutant-degrading culture. The results highlighted the effects of bed drying on cell viability in the control biofilter. They also revealed that the bottom segment of the biofilter with the lower irrigation system had a higher moisture content, a higher biomass density and a larger fraction of active biomass than the corresponding segment in the conventional biofilter. These detailed examinations explained why an increased toluene removal was observed in the system equipped with a lower irrigation system. Overall, this study demonstrates enhanced pollutant removal in biofilters equipped with a lower irrigation system through a better control of moisture.

  5. [Characteristics of microbial community and operation efficiency in biofilter process for drinking water purification].

    PubMed

    Xiang, Hong; Lü, Xi-Wu; Yang, Fei; Yin, Li-Hong; Zhu, Guang-Can

    2011-04-01

    In order to explore characteristics of microbial community and operation efficiency in biofilter (biologically-enhanced active filter and biological activated carbon filter) process for drinking water purification, Biolog and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) techniques were applied to analyze the metabolic function and structure of microbial community developing in biofilters. Water quality parameters, such as NH; -N, NO; -N, permanganate index, UV254 and BDOC etc, were determined in inflow and outflow of biofilters for investigation of operation efficiency of the biofilters. The results show that metabolic capacity of microbial community of the raw water is reduced after the biofilters, which reflect that metabolically active microbial communities in the raw water can be intercepted by biofilters. After 6 months operation of biofilters, the metabolic profiles of microbial communities are similar between two kinds of biologically-enhanced active filters, and utilization of carbon sources of microbial communities in the two filters are 73.4% and 75.5%, respectively. The metabolic profiles of microbial communities in two biological activated carbon filters showed significant difference. The carbon source utilization rate of microbial community in granule-activated carbon filter is 79.6%, which is obviously higher than 53.8% of the rate in the columnar activated carbon filter (p < 0.01). The analysis results of PCR-SSCP indicate that microbial communities in each biofilter are variety, but the structure of dominant microorganisms is similar among different biofilters. The results also show that the packing materials had little effect on the structure and metabolic function of microbial community in biologically-enhanced active filters, and the difference between two biofilters for the water purification efficiency was not significant (p > 0.05). However, in biological activated carbon filters, granule-activated carbon is

  6. Ethylene removal evaluation and bacterial community analysis of vermicompost as biofilter material.

    PubMed

    Fu, Yuming; Shao, Lingzhi; Liu, Hui; Tong, Ling; Liu, Hong

    2011-08-30

    Biofiltration of ethylene provides an environmentally friendly and economically beneficial option relative to physical/chemical removal, where selection of appropriate bed material is crucial. Here the vermicompost with indigenous microorganisms as bed material was evaluated for ethylene removal through batch test and biofilter experiment. Temporal and spatial dynamics of bacterial community in the vermicompost-biofilter under different ethylene loads were characterized by culture and denaturing gradient gel electrophoresis (DGGE) methods. The results showed that ethylene was effectively degraded by the vermicompost under conditions of 25-50% moisture content and 25-35°C temperature. The vermicompost-biofilter achieved nearly 100% ethylene removal up to an inlet load of 11mg m(-3)h(-1). Local nitrogen lack of the vermicompost in the biofilter was observed over operation time, but the change of pH was slight. DGGE analysis demonstrated that the bacterial abundance and community structure of vermicompost-biofilter varied with the height of biofilter under different ethylene loads. Pseudomonads and Actinobacteria were predominant in the biofilter throughout the whole experiment. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Three-stage aged refuse biofilter for the treatment of landfill leachate.

    PubMed

    Li, Hongjiang; Zhao, Youcai; Shi, Lei; Gu, Yingying

    2009-01-01

    A field-scale aged refuse (AR) biofilter constructed in Shanghai Refuse Landfill, containing about 7000 m3 aged refuse inside, was evaluated for its performance in the treatment of landfill leachate. This AR biofilter can be divided into three stages and can manage 50 m3 landfill leachate per day. The physical, chemical, and biological characteristics of AR were analyzed for evaluating the AR biofilter as leachate treatment host. The results revealed that over 87.8%-96.2% of COD and 96.9%-99.4% of ammonia nitrogen were removed by the three-stage AR biofilter when the influent leachate COD and ammonia nitrogen concentration were in the range 5478-10842 mg/L and 811-1582 mg/L, respectively. The final effluent was inodorous and pale yellow with COD and ammonia nitrogen below 267-1020 mg/L and 6-45 mg/L, respectively. The three-stage AR biofilter had efficient nitrification but relative poor denitrification capacity with a total nitrogen (TN) removal of 58%-73%. The external temperature of AR biofilter did not influence the total ammonia nitrogen removal significantly. It was concluded that the scale-up AR biofilter can work very well and can be a promising technology for the treatment of landfill leachate.

  8. Dracaena marginata biofilter: design of growth substrate and treatment of stormwater runoff.

    PubMed

    Vijayaraghavan, K; Praveen, R S

    2016-01-01

    The purpose of this research was to investigate the efficiency of Dracaena marginata planted biofilters to decontaminate urban runoff. A new biofilter growth substrate was prepared using low-cost and locally available materials such as red soil, fine sand, perlite, vermiculite, coco-peat and Sargassum biomass. The performance of biofilter substrate was compared with local garden soil based on physical and water quality parameters. Preliminary analyses indicated that biofilter substrate exhibited desirable characteristics such as low bulk density (1140 kg/m(3)), high water holding capacity (59.6%), air-filled porosity (7.82%) and hydraulic conductivity (965 mm/h). Four different biofilter assemblies, with vegetated and non-vegetated systems, were examined for several artificial rain events (un-spiked and metal-spiked). Results from un-spiked artificial rain events suggested that concentrations of most of the chemical components in effluent were highest at the beginning of rain events and thereafter subsided during the subsequent rain events. Biofilter growth substrate showed superior potential over garden soil to retain metal ions such as Al, Fe, Cu, Cr, Ni, Zn, Cd and Pb during metal-spiked rain events. Significant differences were also observed between non-vegetated and vegetated biofilter assemblies in runoff quality, with the latter producing better results.

  9. Temporal and Spatial Stability of Ammonia-Oxidizing Archaea and Bacteria in Aquarium Biofilters

    PubMed Central

    Sauder, Laura A.; Mosquera, Mariela; Neufeld, Josh D.; Boon, Nico

    2014-01-01

    Nitrifying biofilters are used in aquaria and aquaculture systems to prevent accumulation of ammonia by promoting rapid conversion to nitrate via nitrite. Ammonia-oxidizing archaea (AOA), as opposed to ammonia-oxidizing bacteria (AOB), were recently identified as the dominant ammonia oxidizers in most freshwater aquaria. This study investigated biofilms from fixed-bed aquarium biofilters to assess the temporal and spatial dynamics of AOA and AOB abundance and diversity. Over a period of four months, ammonia-oxidizing microorganisms from six freshwater and one marine aquarium were investigated at 4–5 time points. Nitrogen balances for three freshwater aquaria showed that active nitrification by aquarium biofilters accounted for ≥81–86% of total nitrogen conversion in the aquaria. Quantitative PCR (qPCR) for bacterial and thaumarchaeal ammonia monooxygenase (amoA) genes demonstrated that AOA were numerically dominant over AOB in all six freshwater aquaria tested, and contributed all detectable amoA genes in three aquarium biofilters. In the marine aquarium, however, AOB outnumbered AOA by three to five orders of magnitude based on amoA gene abundances. A comparison of AOA abundance in three carrier materials (fine sponge, rough sponge and sintered glass or ceramic rings) of two three-media freshwater biofilters revealed preferential growth of AOA on fine sponge. Denaturing gel gradient electrophoresis (DGGE) of thaumarchaeal 16S rRNA genes indicated that community composition within a given biofilter was stable across media types. In addition, DGGE of all aquarium biofilters revealed low AOA diversity, with few bands, which were stable over time. Nonmetric multidimensional scaling (NMDS) based on denaturing gradient gel electrophoresis (DGGE) fingerprints of thaumarchaeal 16S rRNA genes placed freshwater and marine aquaria communities in separate clusters. These results indicate that AOA are the dominant ammonia-oxidizing microorganisms in freshwater aquarium

  10. Assessment of Pollutant Removal Efficiency and Drainage Capacity in Stormwater Biofilters

    NASA Astrophysics Data System (ADS)

    Carroll, S. J.; Mills, H.; Reagan, A.; Triassi, M.; Bauer, S.; Matiasek, S. J.; Libby, R.; Meddings, C.

    2016-12-01

    Urban stormwater runoff contributes to flooding and impacts water quality with increased sediment and pollutant loads. Biofilters are vegetated filtration systems designed to mitigate stormwater by enhancing infiltration, sedimentation, contaminant sorption and uptake. Despite the rapid implementation of biofilters as stormwater management solutions, their performance is mainly evaluated in terms of flood reduction while their pollutant removal efficiency is rarely assessed. We investigated the effect of biofilter composition on drainage capacity and individual pollutant removal in test columns. Triplicate columns consisted of layers of pebbles, fine sand, filtration mix (test variable), mulch, lava rock and Santa Barbara sedges. The filtration mix was one of five combinations of coarse sand and local loam soil ranging from 100% sand to 100% soil. Consistent with differences in pore size distribution, hydraulic conductivity values were lowest in 100% soil biofilters (3.0 ± 0.6 mm/h) and highest in the 100% sand biofilters (22.7 ± 4.2 mm/h). A synthetic mixture of nutrients, metals, and salts in proportions representative of stormwater composition was applied to the test columns. Biofilters removed over 98% of dissolved copper, nickel, and zinc, and at least 67% of dissolved lead, even when applying synthetic runoff with metal concentrations three orders of magnitude larger than in actual stormwater. In addition, biofilters oxygenated, neutralized, and decreased the turbidity of stormwater. Ammonium was quantitatively removed from synthetic runoff (97-100%), while nitrate and phosphate were poorly retained (48-64%) or even leached from sand biofilters. This study demonstrated that, while decreasing drainage capacity, adding even a small proportion of native soil to the filtration media significantly increases pollutant removal of biofilters. With proper consideration of the filtration mixture, biofiltration systems can effectively remediate urban stormwater.

  11. Influence of ground tire rubber on the transient loading response of a peat biofilter.

    PubMed

    Alvarez-Hornos, F J; Izquierdo, M; Martínez-Soria, V; Penya-Roja, J M; Sempere, F; Gabaldón, C

    2011-08-01

    The effect of using ground tire rubber (GTR) as an adsorptive material in the removal of a 2:1:1 weight mixture of n-butyl acetate, toluene and m-xylene by using a peat biofilter under different intermittent conditions was investigated. The performance of two identical size biofilters, one packed with fibrous peat alone and the other with a 3:1 (vol) fibrous peat and GTR mixture, was examined for a period of four months. Partition coefficients of both materials were measured. Values of 53, 118 and 402 L kg(-1) were determined for n-butyl acetate, toluene and m-xylene in peat, respectively; and values of 40, 609 and 3035 L kg(-1) were measured for the same compounds in GTR. Intermittent load feeding of 16 h per day, 5 days per week working at an EBRT of 60 s and an inlet VOC concentration of 0.3 g C m(-1), resulted in removal efficiencies higher than 90% for both biofilters, indicating that the addition of GTR did not adversely affect the behavior of the bioreactor. Full removal of n-butyl acetate was obtained for both biofilters. GTR improved the removal of the aromatics in the first part of the biofilter, facilitating lower penetration of the toluene and m-xylene into the bed. A 31-day starvation period was applied and intermittent operation subsequently restarted. In both biofilters, high removal efficiencies after a re-acclimation period of two days were achieved. A shock loading test related to 1-h peaks of three- and four-fold increases in its baseline concentration (0.30 g C m(-3)) was applied in both biofilters. For the biofilter packed with the peat and GTR mixture, attenuation greater than 60% was observed in the maximum outlet concentration when compared to the biofilter packed with peat alone. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. City-Management - Eine Erfolgsstory?!

    NASA Astrophysics Data System (ADS)

    Kuron, Irene

    2002-03-01

    Seit geraumer Zeit wird das Thema Innenstadt kontrovers diskutiert. Neben dem Niedergang der City und der Konkurrenz zur "Grünen Wiese" werden zugleich die europäische urbane Stadt heraufbeschworen und zahlreiche Aktivitäten zur (Re-)Vitalisierung unternommen. Von privaten Initiativen, Händlergemeinschaften über public-private-partnership-Projekte, wie z.B. Ab in die Mitte" in Nordrhein-Westfalen, bis zum städtischen City-Manager und Landesförderung für Innenstadtprojekte reicht das Repertoire. City-Management ist dabei ein wesentliches Instrument. Wie City-Management in Deutschland aussieht und wie es sich entwickelt, zeigt der folgende Beitrag.

  13. Efficacy of a novel biofilter in hatchery sanitation: I. Removal of airborne bacteria, dust and endotoxin.

    PubMed

    Chmielowiec-Korzeniowska, Anna; Tymczyna, Leszek; Skórska, Czesława; Sitkowska, Jolanta; Cholewa, Grazyna; Dutkiewicz, Jacek

    2007-01-01

    A novel biofilter containing organic, bentonite and halloysite media was applied for elimination of microbial pollutants from the air of an industrial hatchery. The concentrations of total mesophilic bacteria, Gram-negative bacteria, thermophilic actinomycetes, dust and bacterial endotoxin were determined in the air of hatchery during 2 months before installation of the biofilter, and during 6 months after installation of the biofilter, at the inlet and outlet ducts from each medium. Before installation of the biofilter, the concentrations of total mesophilic bacteria, Gram-negative bacteria, thermophilic actinomycetes, dust and endotoxin in the air were within the ranges of 0.97-131.2x10(3) cfu/m3, 0.0-34.4x10(3) cfu/m3, 0.0-0.02x10(3) cfu/m3, 0.37-4.53 mg/m3, and 50.9-520,450.4 ng/m3, respectively. Enterococcus faecalis and Gram-negative bacteria (Acinetobacter spp., Escherichia coli, Enterobacter cloacae, and other species) prevailed among bacterial species recovered from the air of the hatchery. A total of 56 species or genera of bacteria were identified in the air samples taken in the examined hatchery; of these, 11, 11 and 6 species or genera respectively were reported as having allergenic, immunotoxic and/or infectious properties The concentrations of total mesophilic bacteria, Gram-negative bacteria, Enterococcus faecalis and endotoxin found at the inlet duct of the biofilter after its installation were significantly smaller compared to those recorded before its installation (p<0.05). The concentrations of Gram-negative bacteria, Enterococcus faecalis and dust found at the outlet ducts of biofilter after its installation were significantly smaller compared to those recorded at the inlet duct of the biofilter (p<0.01). The concentrations of total meso-philic bacteria were also smaller at the outlet ducts of the biofilter compared to that at the inlet duct; however, the difference was not significant because of the massive growth of Streptomyces species in

  14. Non-steady state simulation of BOM removal in drinking water biofilters: applications and full-scale validation.

    PubMed

    Hozalski, R M; Bouwer, E J

    2001-01-01

    A biofilter model called "BIOFILT" was used to simulate the removal of biodegradable organic matter (BOM) in full-scale biofilters subjected to a wide range of operating conditions. Parameters that were varied included BOM composition, water temperature (3.0-22.5 degrees C), and biomass removal during backwashing (0-100%). Results from biofilter simulations suggest a strong dependence of BOM removal on BOM composition. BOM with a greater diffusivity or with faster degradation kinetics was removed to a greater extent and also contributed to shorter biofilter start-up times. In addition, in simulations involving mixtures of BOM (i.e. readily degradable and slowly degradable components), the presence of readily degradable substrate significantly enhanced the removal of slowly degradable material primarily due to the ability to maintain greater biomass levels in the biofilters. Declines in pseudo-steady state BOM removal were observed as temperature was decreased from 22.5 to 3 degrees C and the magnitude of the change was significantly affected by BOM composition. However, significant removals of BOM are possible at low temperatures (3-6 degrees C). Concerning the impact of backwashing on biofilter performance, BOM removal was not affected by backwash resulting in biomass removals of 60% or less. This suggests that periodic backwashing should not significantly impact biofilter performance as observed biomass removals from full-scale biofilters were negligible. In general, the simulation results were in good qualitative and quantitative agreement with experimental results obtained from full-scale biofilters.

  15. Dimethylamine biodegradation by mixed culture enriched from drinking water biofilter.

    PubMed

    Liao, Xiaobin; Chen, Chao; Zhang, Jingxu; Dai, Yu; Zhang, Xiaojian; Xie, Shuguang

    2015-01-01

    Dimethylamine (DMA) is one of the important precursors of drinking water disinfection by-product N-nitrosodimethylamine (NDMA). Reduction of DMA to minimize the formation of carcinogenic NDMA in drinking water is of practical importance. Biodegradation plays a major role in elimination of DMA pollution in the environment, yet information on DMA removal by drinking water biofilter is still lacking. In this study, microcosms with different treatments were constructed to investigate the potential of DMA removal by a mixed culture enriched from a drinking water biofilter and the effects of carbon and nitrogen sources. DMA could be quickly mineralized by the enrichment culture. Amendment of a carbon source, instead of a nitrogen source, had a profound impact on DMA removal. A shift in bacterial community structure was observed with DMA biodegradation, affected by carbon and nitrogen sources. Proteobacteria was the predominant phylum group in DMA-degrading microcosms. Microorganisms from a variety of bacterial genera might be responsible for the rapid DMA mineralization. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Optimization of nutrient supply in a downflow gas-phase biofilter packed with an inert carrier.

    PubMed

    Prado, O J; Mendoza, J A; Veiga, M C; Kennes, C

    2002-08-01

    Several methodologies were tested to supply nutrients to a downflow biofilter packed with perlite and used to treat toluene-polluted air. Despite the presence of an inorganic carrier, elimination capacities of up to around 60 g/m(3) per hour could be maintained when a basal medium, containing nitrogen, phosphorus and potassium, was supplied once every fortnight or even once a month rather than once a week. Experimental results also indicated that the addition of vitamins or trace minerals to the basal aqueous medium hardly improved biofilter performance. Furthermore, the nutrient supply could be combined with a biomass control strategy, using air sparging, without any adverse effect on biofilter performance compared to supplying nutrients alone, and limiting the accumulation of excess biomass on the packing material. The performance of the biofilter was not significantly affected by temperature fluctuations between 25 and 33 degrees C.

  17. Non-isothermal modelling of H2S removal in a biofilter.

    PubMed

    Sami, Samaneh; Rahimi, Amir

    2011-01-01

    In this study the biodegradation of H2S in the air in a biofilter is modelled in the non-isothermal operating condition. For this purpose, using conservation laws of heat and mass transfer and considering the physical and chemical phenomena occurring in a biofilter, the governing equations in non-isothermal, isothermal, steady, and unsteady-state operations are obtained and solved numerically. The model results are compared with the available experimental data and also with the results of the isothermal model. The comparisons are made both in steady and unsteady-state situations. The results show that considering the heat effects on the modelling of a biofilter improves the accuracy of the model results. Furthermore, the effects of some operating parameters on the removal efficiency of biofilter are investigated.

  18. Pyrosequencing Analysis of Bench-Scale Nitrifying BiofiltersRemoving Trihalomethanes

    EPA Science Inventory

    The bacterial biofilm communities in four nitrifying biofilters degrading regulated drinking water trihalomethanes were characterized by 454 pyrosequencing. The three most abundant phylotypes based on total diversity were Nitrosomonas (70%), Nitrobacter (14%), and Chitinophagace...

  19. Pyrosequencing Analysis of Bench-Scale Nitrifying BiofiltersRemoving Trihalomethanes

    EPA Science Inventory

    The bacterial biofilm communities in four nitrifying biofilters degrading regulated drinking water trihalomethanes were characterized by 454 pyrosequencing. The three most abundant phylotypes based on total diversity were Nitrosomonas (70%), Nitrobacter (14%), and Chitinophagace...

  20. Treatment of odor by a seashell biofilter at a wastewater treatment plant.

    PubMed

    Abraham, Samantha; Joslyn, Scott; Suffet, I H Mel

    2015-10-01

    Biofilters are becoming an increasingly popular treatment device for odors and other volatiles found at wastewater treatment plants. A seashell media based biofilter was installed in April 2011 at Lake Wildwood Wastewater Treatment Plant located in Penn Valley, California. It was sampled seasonally to examine its ability to treat odorous compounds found in the air above the anaerobic equalization basin at the front end of the plant and to examine the properties of the biofilter and its recirculating water system. The odor profile method sensory panels found mainly sulfide odors (rotten eggs and rotten vegetable) and some fecal odors. This proved to be a useful guidance tool for selecting the required types of chemical sampling. The predominant odorous compounds found were hydrogen sulfide, methyl mercaptan and dimethyl sulfide. These compounds were effectively removed by the biofilter at greater than 99% removal efficiency therein reducing the chemical concentrations to below their odor thresholds. Aldehydes found in the biofilter were below odor thresholds but served as indicators of biological activity. Gas chromatography with mass spectrometry and gas chromatography with sensory detection showed the presence of dimethyl disulfide and dimethyl trisulfide as well, but barely above their respective odor thresholds. The neutrality of the pH of the recirculating water was variable depending on conditions in the biofilter, but a local neutral pH was found in the shells themselves. Other measurements of the recirculating water indicated that the majority of the bio-activity takes place in the first stage of the biofilter. All measurements performed suggest that this seashell biofilter is successful at removing odors found at Lake Wildwood. This study is an initial examination into the mechanism of the removal of odorous compounds in a seashell biofilter. This paper presents a thorough examination of a seashell media biofilter, a sustainable treatment technology used to

  1. Effect of continuous ozone injection on performance and biomass accumulation of biofilters treating gaseous toluene.

    PubMed

    Xi, Jinying; Saingam, Prakit; Gu, Feng; Hu, Hong-Ying; Zhao, Xuefei

    2014-11-01

    Biofilters treating high-concentration gaseous volatile organic compounds (VOC) can be subject to bed clogging induced by excess biomass accumulation. In this study, O3 was continuously injected into biofilters to control biomass. Its effects on the performance of the biofilters and on biomass accumulation were investigated. Four identical biofilters designed to treat gaseous toluene were operated for 70 days, and three of them were continuously injected with O3 at different concentrations (from 80 to 320 mg/m(3)). The results showed that continuous O3 injection could effectively keep the bed pressure drop stable and had no adverse effect on toluene removal when O3 concentrations were 180-220 mg/m(3). The maximum toluene elimination capacity of the four biofilters was 140 g-toluene/m(3)/h, and the bed pressure drop of the biofilter fed with 180-220 mg/m(3) O3 remained below 3 mmH2O/m throughout the operation period. The biomass accumulation rates of the three biofilters with O3 at 80-320 mg/m(3) were lowered by 0.15-0.25 g/L/day compared with the biofilter without O3. The decreases in biomass accumulation resulted in higher void fractions of the filter beds with O3 injection. Carbon balance analysis indicated that CO2 production had increased while biomass accumulation and leachate waste production decreased in response to O3 injection. Based on the experimental results, it was concluded here that continuous O3 injection can reduce increases in bed pressure effectively, preserve VOC removal capacity, and prevent production of extra leachate waste.

  2. Effect of continuous ozone injection on performance and biomass accumulation of biofilters treating gaseous toluene.

    PubMed

    Xi, Jinying; Saingam, Prakit; Gu, Feng; Hu, Hong-Ying; Zhao, Xuefei

    2015-01-01

    Biofilters treating high-concentration gaseous volatile organic compounds (VOC) can be subject to bed clogging induced by excess biomass accumulation. In this study, O3 was continuously injected into biofilters to control biomass. Its effects on the performance of the biofilters and on biomass accumulation were investigated. Four identical biofilters designed to treat gaseous toluene were operated for 70 days, and three of them were continuously injected with O3 at different concentrations (from 80 to 320 mg/m(3)). The results showed that continuous O3 injection could effectively keep the bed pressure drop stable and had no adverse effect on toluene removal when O3 concentrations were 180-220 mg/m(3). The maximum toluene elimination capacity of the four biofilters was 140 g-toluene/m(3)/h, and the bed pressure drop of the biofilter fed with 180-220 mg/m(3) O3 remained below 3 mmH2O/m throughout the operation period. The biomass accumulation rates of the three biofilters with O3 at 80-320 mg/m(3) were lowered by 0.15-0.25 g/L/day compared with the biofilter without O3. The decreases in biomass accumulation resulted in higher void fractions of the filter beds with O3 injection. Carbon balance analysis indicated that CO2 production had increased while biomass accumulation and leachate waste production decreased in response to O3 injection. Based on the experimental results, it was concluded here that continuous O3 injection can reduce increases in bed pressure effectively, preserve VOC removal capacity, and prevent production of extra leachate waste.

  3. Qualitative and Quantitative Bacteriological Studies on a Fluidized Sand Biofilter Used in a Semiclosed Trout Culture System.

    DTIC Science & Technology

    1993-07-01

    We conducted a study of the numbers and types of heterotrophic bacteria that occur in a fluidized sand biofilter and in rearing water in a semiclosed...trout culture research system at the Freshwater Institute, Shepherdstown, West Virginia. Methods were developed for sampling the biofilter at various...procedures. Sonication of sand from biofilters and a spread plate technique provided the best results in determining total counts of heterotrophic bacteria. In

  4. Biofilter for generation of concentrated sulphuric acid from H2S.

    PubMed

    Rabbani, K A; Charles, W; Kayaalp, A; Cord-Ruwisch, R; Ho, G

    2016-08-01

    Biofilters are used for the conversion of odorous hydrogen sulphide to odourless sulphate in wastewater treatment plants under the right conditions of moisture and pH. One of the consequences of maintaining the suitable pH and moisture content is the production of large volumes of weakly acidic leachate. This paper presents a biofilter with a maximum H2S elimination capacity of 16.3 g m(-3) h(-1) and removal efficiency greater than 95 % which produces small volumes (1 mL of solution L(-1) of reactor day(-1)) of sulphuric acid with a concentration greater than 5.5 M after 150 days of continuous operation. The concentrated sulphuric acid was produced by intermittently trickling a minimum amount of nutrient solution down the upflow biofilter which created a moisture and pH gradient within the biofilter resulting in an environment at the top for the bacterial conversion of H2S, while sulphuric acid was accumulated at the base. Genetic diversity profiling of samples taken from different sections of the biofilter confirms that the upper sections of the biofilter had the best environment for the bacteria to convert H2S to sulphate. The formation of concentrated sulphuric acid presents an opportunity for the recovery of sulphur from the waste stream as a usable product.

  5. The Use of Biofilter to Reduce Atmospheric Global Warming Gas (CH4) Eemissions from Landfills

    NASA Astrophysics Data System (ADS)

    Park, S.; Thomas, J. C.; Brown, K. W.; Sung, K.

    2001-12-01

    The emission of greenhouse gasses resulting from anthropogenic activities is increasing the atmospheric concentration of these gases, which can influence the climatic system by changing the temperature, precipitation, wind and other climate factors. Methane (CH4) is a very potent greenhouse gas and CH4 emission from landfills in US has been reported as 37% of total anthropogenic source of CH4 emission. Properly designed soil biofilters may reduce atmospheric CH4 emissions from landfills and help reduce the accumulation of greenhouse gasses in the atmosphere. Biofilter performance was tested under a variety of environmental and design conditions. The results showed that biofilters have the potential to reduce CH4 emissions from landfills by as much as 83%. A quadratic equation was developed to describe the dependence of methane oxidation rate in a sandy loam textured soil as a function of soil temperature, soil moisture and ammonium nitrogen concentration. Using this equation and the averaged soil temperature and moisture contents, and census data for the largest cities of each of the 48 contiguous states, oxidation rates was calculated. A methane emission model was also developed to estimate the methane emission from municipal waste landfills with different covers. Older landfills with soil covers emitted an average of 83% of the generated CH4. Landfills with RCRA covers emitted 90% of the generated CH4 without biofilters and only 10% with biofilters. Thus, the installation of properly sized biofilters should significantly reduce atmospheric CH4 emissions from landfills.

  6. Biological removal of gaseous ammonia in biofilters: space travel and earth-based applications.

    PubMed

    Joshi, J A; Hogan, J A; Cowan, R M; Strom, P F; Finstein, M S

    2000-09-01

    Gaseous NH3 removal was studied in laboratory-scale biofilters (14-L reactor volume) containing perlite inoculated with a nitrifying enrichment culture. These biofilters received 6 L/min of airflow with inlet NH3 concentrations of 20 or 50 ppm, and removed more than 99.99% of the NH3 for the period of operation (101, 102 days). Comparison between an active reactor and an autoclaved control indicated that NH3 removal resulted from nitrification directly, as well as from enhanced absorption resulting from acidity produced by nitrification. Spatial distribution studies (20 ppm only) after 8 days of operation showed that nearly 95% of the NH3 could be accounted for in the lower 25% of the biofilter matrix, proximate to the port of entry. Periodic analysis of the biofilter material (20 and 50 ppm) showed accumulation of the nitrification product NO3- early in the operation, but later both NO2- and NO3- accumulated. Additionally, the N-mass balance accountability dropped from near 100% early in the experiments to approximately 95 and 75% for the 20- and 50-ppm biofilters, respectively. A partial contributing factor to this drop in mass balance accountability was the production of NO and N2O, which were detected in the biofilter exhaust.

  7. Biological removal of gaseous ammonia in biofilters: space travel and earth-based applications

    NASA Technical Reports Server (NTRS)

    Joshi, J. A.; Hogan, J. A.; Cowan, R. M.; Strom, P. F.; Finstein, M. S.; Janes, H. W. (Principal Investigator)

    2000-01-01

    Gaseous NH3 removal was studied in laboratory-scale biofilters (14-L reactor volume) containing perlite inoculated with a nitrifying enrichment culture. These biofilters received 6 L/min of airflow with inlet NH3 concentrations of 20 or 50 ppm, and removed more than 99.99% of the NH3 for the period of operation (101, 102 days). Comparison between an active reactor and an autoclaved control indicated that NH3 removal resulted from nitrification directly, as well as from enhanced absorption resulting from acidity produced by nitrification. Spatial distribution studies (20 ppm only) after 8 days of operation showed that nearly 95% of the NH3 could be accounted for in the lower 25% of the biofilter matrix, proximate to the port of entry. Periodic analysis of the biofilter material (20 and 50 ppm) showed accumulation of the nitrification product NO3- early in the operation, but later both NO2- and NO3- accumulated. Additionally, the N-mass balance accountability dropped from near 100% early in the experiments to approximately 95 and 75% for the 20- and 50-ppm biofilters, respectively. A partial contributing factor to this drop in mass balance accountability was the production of NO and N2O, which were detected in the biofilter exhaust.

  8. Oxygen Effects on Thermophilic Microbial Populations in Biofilters Treating Nitric Oxide Containing Off-Gas Streams

    SciTech Connect

    Lee, Brady Douglas; Apel, William Arnold; Smith, William Aaron

    2004-04-01

    Electricity generation from coal has increased by an average of 51 billion kWh per year over the past 3 years. For this reason cost-effective strategies to control nitrogen oxides (NOx) from coal-fired power plant combustion gases must be developed. Compost biofilters operated at 55°C at an empty bed contact time (EBCT) of 13 seconds were shown to be feasible for removal of nitric oxide (NO) from synthetic flue gas. Denitrifying microbial populations in these biofilters were shown to reduce influent NO feeds by 90 to 95% at inlet NO concentrations of 500 ppmv. Oxygen was shown to have a significant effect on the NO removal efficiency demonstrated by these biofilters. Two biofilters were set up under identical conditions for the purpose of monitoring NO removal as well as changes in the microbial population in the bed medium under anaerobic and aerobic conditions. Changes in the microbial population were monitored to determine the maximum oxygen tolerance of a denitrifying biofilter as well as methods of optimizing microbial populations capable of denitrification in the presence of low oxygen concentrations. Nitric oxide removal dropped to between 10 and 20% when oxygen was present in the influent stream. The inactive compost used to pack the biofilters may have also caused the decreased NO removal efficiency compared to previous biofiltration experiments. Analysis of the bed medium microbial population using environmental scanning electron microscopy indicated significant increases in biomass populating the surface of the compost when compared to unacclimated compost.

  9. Performance and microbial diversity of aerated trickling biofilter used for treating cheese industry wastewater.

    PubMed

    Saminathan, Sumathi K M; Galvez-Cloutier, Rosa; Kamal, Najat

    2013-05-01

    Wastewater discharged from cheese industries is often characterized by high values of organic pollutants, solids, and nutrients. An aerated trickling biofilter using peat and perlite as filter media was employed in a pilot-scale level in order to evaluate the performance of biofilter for removal of pollutants from cheese industry wastewater. The biofilter was operated for a period of 33 days under laboratory conditions, and several parameters were monitored. The results showed a significant improvement in the quality of treated effluent. The maximum removal efficiencies of chemical oxygen demand and biological oxygen demand were 99.2 and 99.9 %, respectively. Significant reduction in total suspended solids (>96 %) was also achieved. A stable ammoniacal-nitrogen (NH(4)-N) removal was accompanied by biofilter. On an average, NH(4)-N and total nitrogen decreased by 98.7 and 72 %, respectively, with a significant portion of NH(4)-N being converted to nitrate-nitrogen (NO(3)-N). Also, a molecular approach based on 16S rDNA was employed to analyze the bacterial community composition present in the biofilter. A comparative sequence analysis of excised denaturing gradient gel electrophoresis bands revealed the presence of diverse groups of bacteria belonging to α- and β-Proteobacteria and Bacteroidetes phylum. We conclude from the results that the use of trickling biofilter is highly effective and a potential treatment method for polishing cheese industry wastewater before being discharged into the local environment.

  10. Biological removal of gaseous ammonia in biofilters: space travel and earth-based applications

    NASA Technical Reports Server (NTRS)

    Joshi, J. A.; Hogan, J. A.; Cowan, R. M.; Strom, P. F.; Finstein, M. S.; Janes, H. W. (Principal Investigator)

    2000-01-01

    Gaseous NH3 removal was studied in laboratory-scale biofilters (14-L reactor volume) containing perlite inoculated with a nitrifying enrichment culture. These biofilters received 6 L/min of airflow with inlet NH3 concentrations of 20 or 50 ppm, and removed more than 99.99% of the NH3 for the period of operation (101, 102 days). Comparison between an active reactor and an autoclaved control indicated that NH3 removal resulted from nitrification directly, as well as from enhanced absorption resulting from acidity produced by nitrification. Spatial distribution studies (20 ppm only) after 8 days of operation showed that nearly 95% of the NH3 could be accounted for in the lower 25% of the biofilter matrix, proximate to the port of entry. Periodic analysis of the biofilter material (20 and 50 ppm) showed accumulation of the nitrification product NO3- early in the operation, but later both NO2- and NO3- accumulated. Additionally, the N-mass balance accountability dropped from near 100% early in the experiments to approximately 95 and 75% for the 20- and 50-ppm biofilters, respectively. A partial contributing factor to this drop in mass balance accountability was the production of NO and N2O, which were detected in the biofilter exhaust.

  11. Microbiological and kinetic aspects of a biofilter for the removal of toluene from waste gases

    SciTech Connect

    Acuna, M.E.; Perez, F.; Revah, S.; Auria, R.

    1999-04-20

    Microbiological and kinetic aspects of a biofilter inoculated with a consortium of five bacteria and two yeast adapted to remove toluene vapors were investigated. Initially the toluene sorption isotherm on peat and the effect of different environmental conditions on the toluene consumption rates of this consortium were measured. The fast start-up of the biofilter and the decay in the elimination capacity (EC) were reproduced using microcosm assays with toluene successive additions. Nutrient limitation and a large degree of heterogeneity were also detected. EC values, extrapolated from microcosms, were higher than biofilter EC when it was operating close to 100% efficiency but tended to relate better as the biofilter EC diminished. In studies on the microbial evolution in the biofilter, an increase in the cell count and variation in the ecology of the consortium were noted. Bacterial counts up to 10 {times} 10{sup 11} cfu/g{sub dry peat} were found in 88 days, which corresponds to about a 10{sup 4} increase from inoculum. Observations with SEM showed a nonuniform biofilm development on the support and the presence of an extracellular material. The results obtained in this work demonstrated that activity measurement in microcosms concomitant to the biofilter operation could be an important tool for understanding, predicting and improving the biofiltration performance.

  12. Efficient total nitrogen removal in an ammonia gas biofilter through high-rate OLAND.

    PubMed

    De Clippeleir, Haydée; Courtens, Emilie; Mosquera, Mariela; Vlaeminck, Siegfried E; Smets, Barth F; Boon, Nico; Verstraete, Willy

    2012-08-21

    Ammonia gas is conventionally treated in nitrifying biofilters; however, addition of organic carbon to perform post-denitrification is required to obtain total nitrogen removal. Oxygen-limited autotrophic nitrification/denitrification (OLAND), applied in full-scale for wastewater treatment, can offer a cost-effective alternative for gas treatment. In this study, the OLAND application thus was broadened toward ammonia loaded gaseous streams. A down flow, oxygen-saturated biofilter (height of 1.5 m; diameter of 0.11 m) was fed with an ammonia gas stream (248 ± 10 ppmv) at a loading rate of 0.86 ± 0.04 kg N m(-3) biofilter d(-1) and an empty bed residence time of 14 s. After 45 days of operation a stable nitrogen removal rate of 0.67 ± 0.06 kg N m(-3) biofilter d(-1), an ammonia removal efficiency of 99%, a removal of 75-80% of the total nitrogen, and negligible NO/N(2)O productions were obtained at water flow rates of 1.3 ± 0.4 m(3) m(-2) biofilter section d(-1). Profile measurements revealed that 91% of the total nitrogen activity was taking place in the top 36% of the filter. This study demonstrated for the first time highly effective and sustainable autotrophic ammonia removal in a gas biofilter and therefore shows the appealing potential of the OLAND process to treat ammonia containing gaseous streams.

  13. Preliminary acclimation strategies for successful startup in conventional biofilters.

    PubMed

    Elías, Ana; Barona, Astrid; Gallastegi, Gorka; Rojo, Naiara; Gurtubay, Luis; Ibarra-Berastegi, Gabriel

    2010-08-01

    The question of how to obtain the best inocula for conventional biofilters arises when an acclimation/adaptation procedure is to be applied. Bearing in mind that no standardized procedure for acclimating inocula exists, certain preliminary strategies for obtaining an active inoculum from wastewater treatment sludge are proposed in this work. Toluene was the contaminant to be degraded. Concerning the prior separation of sludge phases, no obvious advantage was found in separating the supernatant phase of the sludge before acclimation. As far as a continuous or discontinuous acclimation mode is concerned, the latter is recommended for rapidly obtaining acclimated sludge samples by operating the system for no longer than 1 month. The continuous mode rendered similar degradation rates, although it required longer operating time. Nevertheless, the great advantage of the continuous system lay in the absence of daily maintenance and the ready availability of the activated sample.

  14. Biodegradation of alpha-pinene in model biofilms in biofilters.

    PubMed

    Miller, Martha J; Allen, D Grant

    2005-08-01

    Treatment of air pollutants in a biofilter requires that the compound be effectively transported from the gas phase to the organisms that reside in a biofilm that forms upon a packing material. Models of biofiltration generally treat the biofilm like water by using a Henry's law constant to predict mass transfer rates into the biofilm where degradation occurs and, hence, predict low rates for hydrophobic compounds. However, some compounds that are virtually insoluble in water are also treated unusually well. The objective of this study was to develop a fundamental understanding of the apparent enhanced degradation of hydrophobic pollutants in biofilms. Specifically, the goals of this study were to experimentally determine transport and reaction rates of hydrophobic pollutants in artificial biofilms. We studied the transport and reaction rates of alpha-pinene (as a model hydrophobic pollutant) in a headspace in contact with a well-defined biofilm made up of biomass immobilized in low melting point agarose and found that reaction rates were similar in order of magnitude to biofilter rates. The transport rates through these films once deactivated were found to be the same as through agar (diffusion coefficient between 2.6 and 3.4 x 10(-6) cm2/s). The degradation rates through model biofilms ranged from 2 to 4 x 10(-7) (g/(cm2 min)). A new explanation of high degradation rates was put forth whereby a biologically mediated transformation is taking place in which alpha-pinene is oxidized into a more soluble, less volatile compound that can then penetrate deeper into the biofilm. The formation of this more soluble byproduct was confirmed with batch kinetics experiments using filtered samples, and its proposed identity is cis-2,8-p-menthadien-1-ol, a menthadienol, a novel metabolite of alpha-pinene degradation. A simple conceptual model based on these results is also presented.

  15. Aquarium Nitrification Revisited: Thaumarchaeota Are the Dominant Ammonia Oxidizers in Freshwater Aquarium Biofilters

    PubMed Central

    Sauder, Laura A.; Engel, Katja; Stearns, Jennifer C.; Masella, Andre P.; Pawliszyn, Richard; Neufeld, Josh D.

    2011-01-01

    Ammonia-oxidizing archaea (AOA) outnumber ammonia-oxidizing bacteria (AOB) in many terrestrial and aquatic environments. Although nitrification is the primary function of aquarium biofilters, very few studies have investigated the microorganisms responsible for this process in aquaria. This study used quantitative real-time PCR (qPCR) to quantify the ammonia monooxygenase (amoA) and 16S rRNA genes of Bacteria and Thaumarchaeota in freshwater aquarium biofilters, in addition to assessing the diversity of AOA amoA genes by denaturing gradient gel electrophoresis (DGGE) and clone libraries. AOA were numerically dominant in 23 of 27 freshwater biofilters, and in 12 of these biofilters AOA contributed all detectable amoA genes. Eight saltwater aquaria and two commercial aquarium nitrifier supplements were included for comparison. Both thaumarchaeal and bacterial amoA genes were detected in all saltwater samples, with AOA genes outnumbering AOB genes in five of eight biofilters. Bacterial amoA genes were abundant in both supplements, but thaumarchaeal amoA and 16S rRNA genes could not be detected. For freshwater aquaria, the proportion of amoA genes from AOA relative to AOB was inversely correlated with ammonium concentration. DGGE of AOA amoA genes revealed variable diversity across samples, with nonmetric multidimensional scaling (NMDS) indicating separation of freshwater and saltwater fingerprints. Composite clone libraries of AOA amoA genes revealed distinct freshwater and saltwater clusters, as well as mixed clusters containing both freshwater and saltwater amoA gene sequences. These results reveal insight into commonplace residential biofilters and suggest that aquarium biofilters may represent valuable biofilm microcosms for future studies of AOA ecology. PMID:21858055

  16. Improving hexane removal by enhancing fungal development in a microbial consortium biofilter.

    PubMed

    Arriaga, Sonia; Revah, Sergio

    2005-04-05

    The removal of hydrophobic pollutants in biofilters is often limited by gas liquid mass transfer to the biotic aqueous phase where biodegradation occurs. It has been proposed that the use of fungi may improve their removal efficiency. To confirm this, the uptake of hexane vapors was investigated in 2.6-L perlite-packed biofilters, inoculated with a mixed culture containing bacteria and fungi, which were operated under neutral or acid conditions. For a hexane inlet load of around 140 g.m-3.h-1, elimination capacities (EC) of 60 and 100 g.m-3.h-1 were respectively reached with the neutral and acid systems. Increasing the inlet hexane load showed that the maximum EC obtained in the acid biofilter (150 g.m-3.h-1) was twice greater than in the neutral filter. The addition of bacterial inhibitors had no significant effect on EC in the acid system. The biomass in the acid biofilter was 187 mg.g-1 (dry perlite) without an important pressure drop (26.5 mm of water.m-1reactor). The greater efficiency obtained with the acid biofilter can be related to the hydrophobic aerial hyphae which are in direct contact with the gas and can absorb the hydrophobic compounds faster than the flat bacterial biofilms. Two fungi were isolated from the acid biofilter and were identified as Cladosporium and Fusarium spp. Hexane EC of 40 g.m-3.h-1 for Cladosporium sp. and 50 g.m-3.h-1 for Fusarium sp. were obtained in short time experiments in small biofilters (0.230 L). A biomass content around 30 mg.g-1 (dry perlite) showed the potential for hexane biofiltration of the strains.

  17. The effect of various environmental and design parameters on methane oxidation in a model biofilter.

    PubMed

    Park, Soyoung; Brown, Kirk W; Thomas, James C

    2002-10-01

    Methane from landfills built with RCRA (Resource Conservation and Recovery Act) covers is frequently vented directly to the atmosphere. Alternatively, landfill gasses could be vented through a layer of soil that could serve as a biofilter to oxidize CH4 to carbon dioxide and water. Properly designed soil biofilters may reduce atmospheric CH4 emissions from landfills and help reduce the accumulation of greenhouse gasses in the atmosphere. This study was conducted to investigate the performance of a lab-scale model biofilter system using soil as the filterbed medium in packed columns to measure the effect of a variety of environmental and design factors on the CH4 oxidation capacity of a soil biofilter. Biofilter performance was tested under a variety of environmental and design conditions. The optimum soil moisture content for CH4 oxidation in a loamy sand was 13% by weight. Addition of NO3-N did not affect the CH4 oxidation rate. Soil depths of 30 cm and 60 cm were equally efficient in CH4 oxidation. When the CH4 loading rate was decreased, the percentage of CH4 oxidized increased. The maximum CH4 oxidation rate was 27.2 mol m(-2) d(-1) under optimum conditions.

  18. Effect of weathering on mobilization of biochar particles and bacterial removal in a stormwater biofilter.

    PubMed

    Mohanty, Sanjay K; Boehm, Alexandria B

    2015-11-15

    To improve bacterial removal, a traditional stormwater biofilter can be augmented with biochar, but it is unknown whether bacterial removal remains consistent as the biochar weathers during intermittent exposure to stormwater under dry-wet and freeze-thaw cycles. To examine the effect of weathering on bacterial removal capacity of biochar, we subjected biochar-augmented sand filters (or simplified biofilters) to multiple freeze-thaw or dry-wet cycles for a month and then compared their bacterial removal capacity with the removal capacity of unweathered biofilters. To isolate the effect of physical and chemical weathering processes from that of biological processes, the biofilters were operated without any developed biofilm. Biochar particles were mobilized during intermittent infiltration of stormwater, but the mobilization depended on temperature and antecedent conditions. During stormwater infiltration without intermediate drying, exposure to natural organic matter (NOM) in the stormwater decreased the bacterial removal capacity of biochar, partly due to exhaustion of attachment sites by NOM adsorption. In contrast, exposure to the same amount of NOM during stormwater infiltration with intermediate drying resulted in higher bacterial removal. This result suggests that dry-wet cycles may enhance recovery of the previously exhausted attachment sites, possibly due to diffusion of NOM from biochar surfaces into intraparticle pores during intermediate drying periods. Overall, these results indicate that physical weathering has net positive effect on bacterial removal by biochar-augmented biofilters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Design and performance of a trickling air biofilter for chlorobenzene and o-dichlorobenzene vapors.

    PubMed Central

    Oh, Y S; Bartha, R

    1994-01-01

    From contaminated industrial sludge, two stable multistrain microbial enrichments (consortia) that were capable of rapidly utilizing chlorobenzene and o-dichlorobenzene, respectively, were obtained. These consortia were characterized as to their species composition, tolerance range, and activity maxima in order to establish and maintain the required operational parameters during their use in biofilters for the removal of chlorobenzene contaminants from air. The consortia were immobilized on a porous perlite support packed into filter columns. Metered airstreams containing the contaminant vapors were partially humidified and passed through these columns. The vapor concentrations prior to and after biofiltration were measured by gas chromatography. Liquid was circulated concurrently with the air, and the device was operated in the trickling air biofilter mode. The experimental arrangement allowed the independent variation of liquid flow, airflow, and solvent vapor concentrations. Bench-scale trickling air biofilters removed monochlorobenzene, o-dichlorobenzene, and their mixtures at rates of up to 300 g of solvent vapor h(-1) m(-3) filter volume. High liquid recirculation rates and automated pH control were critical for stable filtration performance. When the accumulating NaCl was periodically diluted, the trickling air biofilters continued to remove chlorobenzenes for several months with no loss of activity. The demonstrated high performance and stability of the described trickling air biofilters favor their use in industrial-scale air pollution control. PMID:8085815

  20. Temporal variation of microbial population in a thermophilic biofilter for SO₂ removal.

    PubMed

    Zhang, Jingying; Li, Lin; Liu, Junxin

    2016-01-01

    The performance of a biofilter relies on the activity of microorganisms during the gas contaminant treatment process. In this study, SO2 was treated using a laboratory-scale biofilter packed with polyurethane foam cubes (PUFC), on which thermophilic desulfurization bacteria were attached. The thermophilic biofilter effectively reduced SO2 within 10months of operation time, with a maximum elimination capacity of 48.29 g/m(3)/hr. Temporal shifts in the microbial population in the thermophilic biofilter were determined through polymerase chain reaction-denaturing gradient gel electrophoresis and deoxyribonucleic acid (DNA) sequence analysis. The substrate species and environmental conditions in the biofilter influenced the microbial population. Oxygen distribution in the PUFC was analyzed using a microelectrode. When the water-containing rate in PUFC was over 98%, the oxygen distribution presented aerobic-anoxic-aerobic states along the test route on the PUFC. The appearance of sulfate-reducing bacteria was caused by the anaerobic conditions and sulfate formation after 4months of operation. Copyright © 2015. Published by Elsevier B.V.

  1. Estimation of mass transfer and kinetics in operating biofilters for removal of VOCs

    SciTech Connect

    Barton, J.W.; Davison, B.H.; Gable, C.C.

    1997-11-18

    Long-term, stable operation of trickle-bed bioreactors remains desirable, but is difficult to achieve for industrial processes, which generate continuous streams of dilute gaseous hydrocarbons. Mass transfer and kinetic parameters are difficult to measure, complicating predictive estimates. Two methods are presented which were used to predict the importance of mass transfer versus kinetics limitations in operating trickle-bed biofilters. Both methods altered the overall kinetic activity of the biofilter and estimated the effective mass transfer coefficient (K{sub 1}a) by varying the VOC (volatile organic contaminant) loading rate and concentration. The first method, used with developing biofilters possessing low biomass, involved addition of cultured biomass to the recirculating liquid to effect an overall change in VOC removal capacity. The second method altered the total bed temperature of a well-established biofilter to effect a change. Results and modeling from these experiments are presented for a mixed culture biofilter which is capable of consuming sparingly soluble alkanes, such as pentane and isobutane. Methods to control overgrowth are discussed which were used to operate one reactor continuously for over 24 months with sustained degradation of VOC alkanes with a rate of 50 g/h/m{sup 3}.

  2. Relationships between biomass, pressure drop, and performance in a polyurethane biofilter.

    PubMed

    Ryu, Hee Wook; Cho, Kyung-Suk; Chung, Dong Jin

    2010-03-01

    In biofilters for controlling volatile organic compounds (VOCs), clogging in the filter bed due to overgrowth of biomass causes the deterioration of biofilter performance. In this study, the relationships between biofilter performance, biomass concentration (X), and pressure drop (DeltaP) was qualitatively and quantitatively evaluated in a polyurethane (PU) biofilter. Benzene was used as a model VOC. The relationship between DeltaP and X at a moisture content of 80-90% was expressed as log DeltaP (mm H(2)Om(-1))=0.315+3.87 log X (g-dry cell weight (DCW) g-PU(-1)), 0.8biofilter performance for long-term operation.

  3. PLFA profiles of drinking water biofilters with different acetate and glucose loadings.

    PubMed

    Yu, Xin; Shi, Xu; Wei, Bo; Ye, Lin; Zhang, Shuting

    2009-08-01

    The biofilters fed with acetate or glucose and their phospholipid fatty acid (PLFA) profiles were investigated to observe the impact of organic matter concentrations on the microbial community structure in the drinking water production system. PLFA markers for bacteria were predominant in all of the biofilters and made up over half of the total PLFA content. PLFA diversity was compared and the biofilters fed with glucose had higher diversity. The Shannon-Wiener (or sometimes known as just Shannon diversity index) indices in the biofilters fed with acetate were from 0.68 to 0.97, while the indices in the biofilters fed with glucose were from 0.95 to 1.25. Principle components analysis showed that carbon sources and media depth were responsible for 68 and 17% of the total PLFA variance, respectively. The results indicated that PLFA analysis could be useful in illustrating microbial community structure in drinking water bioreactors, and microbial community structure was impacted by carbon substrates.

  4. Two-stage biofilter for effective NH3 removal from waste gases containing high concentrations of H2S.

    PubMed

    Chung, Ying-Chien; Ho, Kuo-Ling; Tseng, Ching-Ping

    2007-03-01

    A high H2S concentration inhibits nitrification when H2S and NH3 are simultaneously treated in a single biofilter. To improve NH3 removal from waste gases containing concentrated H2S, a two-stage biofilter was designed to solve the problem. In this study, the first biofilter, inoculated with Thiobacillus thioparus, was intended mainly to remove H2S and to reduce the effect of H2S concentration on nitrification in the second biofilter, and the second biofilter, inoculated with Nitrosomonas europaea, was to remove NH3. Extensive studies, which took into account the characteristics of gas removal, the engineering properties of the two biofilters, and biological parameters, were conducted in a 210-day operation. The results showed that an average 98% removal efficiency for H2S and a 100% removal efficiency for NH3 (empty bed retention time = 23-180 sec) were achieved after 70 days. The maximum degradation rate for NH3 was measured as 2.35 g N day(-1) kg of dry granular activated carbon(-1). Inhibition of nitrification was not found in the biofilter. This two-stage biofilter also exhibited good adaptability to shock loading and shutdown periods. Analysis of metabolic product and observation of the bacterial community revealed no obvious acidification or alkalinity phenomena. In addition, a lower moisture content (approximately 40%) for microbial survival and low pressure drop (average 24.39 mm H2O m(-1)) for system operation demonstrated that the two-stage biofilter was energy saving and economic. Thus, the two-stage biofilter is a feasible system to enhance NH3 removal in the concentrated coexistence of H2S.

  5. Ethylene Removal at Low Temperatures under Biofilter and Batch Conditions

    PubMed Central

    Elsgaard, Lars

    2000-01-01

    Removal of the plant hormone ethylene (C2H4) is often required by horticultural storage facilities, which are operated at temperatures below 10°C. The aim of this study was to demonstrate an efficient, biological C2H4 removal under such low-temperature conditions. Peat-soil, acclimated to degradation of C2H4, was packed in a biofilter (687 cm3) and subjected to an airflow (∼73 ml min−1) with 2 ppm (μl liter−1) C2H4. The C2H4 removal efficiencies achieved at 20, 10, and 5°C, respectively, were 99.0, 98.8, and 98.4%. This corresponded to C2H4 levels of 0.022 to 0.032 ppm in the biofilter outlet air. At 2°C, the average C2H4 removal efficiency dropped to 83%. The detailed temperature response of C2H4 removal was tested under batch conditions by incubation of 1-g soil samples in a temperature gradient ranging from 0 to 29°C with increments of 1°C. The C2H4 removal rate was highest at 26°C (0.85 μg of C2H4 g [dry weight]−1 h−1), but remained at levels of 0.14 to 0.28 μg of C2H4 g (dry weight)−1 h−1 at 0 to 10°C. At 35 to 40°C, the C2H4 removal rate was negligible (0.02 to 0.06 μg of C2H4 g [dry weight]−1 h−1). The Q10 (i.e., the ratio of rates 10°C apart) for C2H4 removal was 1.9 for the interval 0 to 10°C. In conclusion, the present results demonstrated microbial C2H4 removal, which proceeded at 0 to 2°C and produced a moderately psychrophilic temperature response. PMID:10966403

  6. A novel miniaturized biofilter based on silicon micropillars for nucleic acid extraction.

    PubMed

    Petralia, Salvatore; Sciuto, Emanuele Luigi; Conoci, Sabrina

    2016-12-19

    New miniaturised microfluidic biofilter (BF) devices based on silicon micropillars have been developed and tested regarding their ability to extract HBV (Hepatitis B Virus) bacterial DNA from biological sample solutions. The device is composed of a silicon microchannel in which the pillars are distributed at the bottom surface. The extracted DNA solutions were analysed by real time PCR amplification and the biofilter performance was evaluated. The results obtained show that the DNA binding to the biofilters and the elution efficiency strictly depend on the pillars' geometrical dimensions and increase proportionally with the surface/volume ratio. The device exhibiting the best extraction efficiency was then tested in combination with a silicon integrated real time PCR amplification chip as a preliminary step towards the development of genetic point-of-care devices.

  7. [Treatment of Flue Gas from Sludge Drying Process by A Thermophilic Biofilter].

    PubMed

    Chen, Wen-he; Deng, Ming-jia; Luo, Hui; Ding, Wen-iie; Li, Lin; Lin, Jian; Liu, Jun-xin

    2016-01-15

    A thermophilic biofilter was employed to treat the flue gas generated from sludge drying process, and the performance in both the start period and the stationary phase was studied under the gas flow rate of 2 700-3 100 m3 x h(-1) and retention time of 21.88-25.10 s. The results showed that the thermophilic biofilter could effectively treat gases containing sulfur dioxide, ammonia and volatile organic compounds (VOC). The removal efficiencies could reach 100%, 93.61% and 87.01%, respectively. Microbial analysis indicated that most of the population belonged to thermophilic bacteria. Paenibacillus sp., Chelatococcus sp., Bacillus sp., Clostridium thermosuccinogenes, Pseudoxanthomonas sp. and Geobacillus debilis which were abundant in the thermophilic biofilter, had the abilities of denitrification, desulfurization and degradation of volatile organic compounds.

  8. Removal of alpha-pinene from gases using biofilters containing fungi

    NASA Astrophysics Data System (ADS)

    van Groenestijn, J. W.; Liu, J. X.

    Biofiltration is cost-effective for the treatment of gases containing low concentrations of volatile organic compounds (<3 g m -3) . However, conventional biofilters, based on compost and bacterial activity, face problems with the elimination of hydrophobic compounds. Besides that, biofilter operational stability is often hampered by acidification and drying out of the filter bed. To overcome these problems, biofilters with fungi on inert packing material have been developed. Fungi are more resistant to acid and dry conditions than bacteria, and it is hypothesised that the aerial mycelia of fungi, which are in direct contact with the gas, can take up hydrophobic compounds faster than flat aqueous bacterial biofilm surfaces. Alpha-pinene was chosen as a model compound. It is an odorous compound emitted by the wood processing industry. In 2 l biofilter columns four different packing materials were tested: perlite, expanded clay granules, polyurethane foam cubes and compost. The filters were inoculated with forest soil and ventilated with gas containing alpha-pinene. Start up took 1-2 months and removal efficiencies of more than 90% were observed, but mostly ranged from 50% to 90% due to overloading. In the filters containing perlite, clay, polyurethane and compost volumetric removal capacities of, respectively, 24, 33, 38 and 24 g alpha- pinene m -3 filter bed h -1 were attained and the gas pressure drops in the 60 cm high filter beds measured at a superficial gas velocity of 35 m h -1 were 70, 550, 180 and 250 Pa. The results indicate that it is possible to develop biofilters based on the action of fungi with higher elimination capacities for alpha-pinene as reported in literature for bacterial biofilters. The use of polyurethane foam cubes is preferred because of the low gas pressure drop in combination with a high volumetric elimination capacity.

  9. Genomic analyses with biofilter 2.0: knowledge driven filtering, annotation, and model development.

    PubMed

    Pendergrass, Sarah A; Frase, Alex; Wallace, John; Wolfe, Daniel; Katiyar, Neerja; Moore, Carrie; Ritchie, Marylyn D

    2013-12-30

    The ever-growing wealth of biological information available through multiple comprehensive database repositories can be leveraged for advanced analysis of data. We have now extensively revised and updated the multi-purpose software tool Biofilter that allows researchers to annotate and/or filter data as well as generate gene-gene interaction models based on existing biological knowledge. Biofilter now has the Library of Knowledge Integration (LOKI), for accessing and integrating existing comprehensive database information, including more flexibility for how ambiguity of gene identifiers are handled. We have also updated the way importance scores for interaction models are generated. In addition, Biofilter 2.0 now works with a range of types and formats of data, including single nucleotide polymorphism (SNP) identifiers, rare variant identifiers, base pair positions, gene symbols, genetic regions, and copy number variant (CNV) location information. Biofilter provides a convenient single interface for accessing multiple publicly available human genetic data sources that have been compiled in the supporting database of LOKI. Information within LOKI includes genomic locations of SNPs and genes, as well as known relationships among genes and proteins such as interaction pairs, pathways and ontological categories.Via Biofilter 2.0 researchers can:• Annotate genomic location or region based data, such as results from association studies, or CNV analyses, with relevant biological knowledge for deeper interpretation• Filter genomic location or region based data on biological criteria, such as filtering a series SNPs to retain only SNPs present in specific genes within specific pathways of interest• Generate Predictive Models for gene-gene, SNP-SNP, or CNV-CNV interactions based on biological information, with priority for models to be tested based on biological relevance, thus narrowing the search space and reducing multiple hypothesis-testing. Biofilter is a software

  10. Testing a biofilter cover design to mitigate dairy effluent pond methane emissions.

    PubMed

    Pratt, Chris; Deslippe, Julie; Tate, Kevin R

    2013-01-02

    Biofiltration, whereby CH(4) is oxidized by methanotrophic bacteria, is a potentially effective strategy for mitigating CH(4) emissions from anaerobic dairy effluent lagoons/ponds, which typically produce insufficient biogas for energy recovery. This study reports on the effectiveness of a biofilter cover design at oxidizing CH(4) produced by dairy effluent ponds. Three substrates, a volcanic pumice soil, a garden-waste compost, and a mixture of the two, were tested as media for the biofilters. All substrates were suspended as 5 cm covers overlying simulated dairy effluent ponds. Methane fluxes supplied to the filters were commensurate with emission rates from typical dairy effluent ponds. All substrates oxidized more than 95% of the CH(4) influx (13.9 g CH(4) m(-3) h(-1)) after two months and continued to display high oxidation rates for the remaining one month of the trial. The volcanic soil biofilters exhibited the highest oxidation rates (99% removal). When the influx CH(4) dose was doubled for a month, CH(4) removal rates remained >90% for all substrates (maximum = 98%, for the volcanic soil), suggesting that biofilters have a high capacity to respond to increases in CH(4) loads. Nitrous oxide emissions from the biofilters were negligible (maximum = 19.9 mg N(2)O m(-3) h(-1)) compared with CH(4) oxidation rates, particularly from the volcanic soil that had a much lower microbial-N (75 mg kg(-1)) content than the compost-based filters (>240 mg kg(-1)). The high and sustained CH(4) oxidation rates observed in this laboratory study indicate that a biofilter cover design is a potentially efficient method to mitigate CH(4) emissions from dairy effluent ponds. The design should now be tested under field conditions.

  11. Bacterial dynamics in steady-state biofilters: beyond functional stability.

    PubMed

    Cabrol, Léa; Malhautier, Luc; Poly, Franck; Lepeuple, Anne-Sophie; Fanlo, Jean-Louis

    2012-01-01

    The spatial and temporal dynamics of microbial community structure and function were surveyed in duplicated woodchip-biofilters operated under constant conditions for 231 days. The contaminated gaseous stream for treatment was representative of composting emissions, included ammonia, dimethyl disulfide and a mixture of five oxygenated volatile organic compounds. The community structure and diversity were investigated by denaturing gradient gel electrophoresis on 16S rRNA gene fragments. During the first 42 days, microbial acclimatization revealed the influence of operating conditions and contaminant loading on the biofiltration community structure and diversity, as well as the limited impact of inoculum compared to the greater persistence of the endogenous woodchip community. During long-term operation, a high and stable removal efficiency was maintained despite a highly dynamic microbial community, suggesting the probable functional redundancy of the community. Most of the contaminant removal occurred in the first compartment, near the gas inlet, where the microbial diversity was the highest. The stratification of the microbial structures along the filter bed was statistically correlated to the longitudinal distribution of environmental conditions (selective pressure imposed by contaminant concentrations) and function (contaminant elimination capacity), highlighting the central role of the bacterial community. The reproducibility of microbial succession in replicates suggests that the community changes were presumably driven by a deterministic process.

  12. Biofiltration of Chloroform in a Trickle Bed Air Biofilter Under ...

    EPA Pesticide Factsheets

    In this paper, the application of biofiltration is investigated for controlled removal of gas phase chloroform through cometabolic degradation with ethanol. A trickle bed air biofilter (TBAB) operated under acidic pH 4 is subjected to aerobic biodegradation of chloroform and ethanol. The TBAB is composed of pelleted diatomaceous earth filter media inoculated with filamentous fungi species, which served as the principle biodegrading microorganism. The removal efficiencies of 5 ppmv of chloroform mixed with different ratios of ethanol as cometabolite (25, 50, 100, 150, and 200 ppmv) ranged between 69.9 and 80.9%. The removal efficiency, reaction rate kinetics, and the elimination capacity increased proportionately with an increase in the cometabolite concentration. The carbon recovery from the TBAB amounted to 69.6% of the total carbon input. It is postulated that the remaining carbon contributed to excess biomass yield within the system. Biomass control strategies such as starvation and stagnation were employed at different phases of the experiment. The chloroform removal kinetics provided a maximum reaction rate constant of 0.0018 s−1. The highest ratio of chemical oxygen demand (COD)removal/nitrogenutilization was observed at 14.5. This study provides significant evidence that the biodegradation of a highly chlorinated methane can be favored by cometabolism in a fungi-based TBAB. Chloroform is volatile hazardous chemical emitted from publicly owned treatment

  13. Biofilter for removal of nitrogen oxides from contaminated gases under aerobic conditions

    DOEpatents

    Apel, W.A.

    1998-08-18

    A biofilter is described for reducing concentrations of gaseous nitrogen oxides in a polluted gas comprises a porous organic filter bed medium disposed in a housing, the filter bed medium including a mixed culture of naturally occurring denitrifying bacteria for converting the nitrogen oxides to nitrogen gas, carbon dioxide, and water. A method is described of reducing concentrations of nitrogen oxides in polluted gas comprises conducting the polluted gas through the biofilter so that the denitrifying bacteria can degrade the nitrogen oxides. A preferred filter medium is wood compost, however composts of other organic materials are functional. Regulation of pH, moisture content, exogenous carbon sources, and temperature are described. 6 figs.

  14. Development of biofilters to treat the pesticides wastes from spraying applications.

    PubMed

    Pigeon, O; de Vleeschouwer, C; Cors, F; Weickmans, B; de Ryckel, B; Pussemier, L; Debongnie, Ph; Culot, M

    2005-01-01

    Several studies carried out in Europe showed the importance of direct losses to the contamination of surface water by pesticides. These pesticides losses can occur at the farm site when the sprayer equipment is filled with the pesticide formulation (spills, overflowing, leaking) and during the clean-up (rinsing) of the sprayer after the treatment. In Belgium studies are carried out on biofilters to treat in an efficient way effluents containing pesticides. The biofilter substrate is elaborated from a homogenised mixture of local soil, chopped straw and peat or composted material, able to absorb or degrade the active substances. Biofilters consist in systems of 2 or 3 units depending on the spray equipment of the farmer and on the configuration of the farmyard. Each unit is made from a 1 m3 plastic container and the different units are stacked in a vertical pile and connected between them using plastic valves and pipes. Eight pilot systems were installed in March 2002 in seven farms and in one agricultural school, all selected in the loamy region of Belgium specialised in arable crops such as cereals, sugar beets and vegetables. The efficacy (yield) of the systems was determined by measuring the balance of the inputs and outputs of the pesticides. Results were expressed in percent of pesticide retained on the biofilters. The results obtained after two years with 5 tracer pesticides (atrazine, carbofuran, diuron, lenacil and simazine) brought on the biofilter installations are very satisfactory since the percentage of retention is generally higher than 95% of the amount applied. In the beginning of 2004, ten new pilot biofilters were installed in several farms or agricultural technical centres (producing cereals, sugar beets, potatoes, vegetables, fruits or ornamental plants), and in a municipal maintenance service. Some biofilters were installed in duplicate in order to compare the efficacy of different substrates. The efficacy of the biofilters was studied for the

  15. Biofilter for removal of nitrogen oxides from contaminated gases under aerobic conditions

    DOEpatents

    Apel, William A.

    1998-01-01

    A biofilter for reducing concentrations of gaseous nitrogen oxides in a polluted gas comprises a porous organic filter bed medium disposed in a housing, the filter bed medium including a mixed culture of naturally occurring denitrifying bacteria for converting the nitrogen oxides to nitrogen gas, carbon dioxide, and water. A method of reducing concentrations of nitrogen oxides in polluted gas comprises conducting the polluted gas through the biofilter so that the denitrifying bacteria can degrade the nitrogen oxides. A preferred filter medium is wood compost, however composts of other organic materials are functional. Regulation of pH, moisture content, exogenous carbon sources, and temperature are described.

  16. Applying trait-function relationships for microbial plant decomposition to predict medium longevity in pollution control biofilters.

    PubMed

    Oliver, Jason P; Schilling, Jonathan S

    2016-03-01

    Biofilters, bioreactors used for pollution control, can effectively treat a variety of odorous and hazardous emissions, but uncertain medium longevities and associated costs limit biofilter adoption. To improve medium-life estimations for biofilter end-users, litter bags were used to compare decay rates of common biofilter medium types and test the effects of nitrogen (N) enrichment and livestock production emissions on medium decay in a full-scale biofilter over a 27-month period. Generally, "by-product" media (mulch, corn cobs) decayed faster than hardwood media, with decay of softwood media the slowest. Analysis showed nutrient content was the best predictor of early-stage decay, while carbon fractions and nutrient content best predicted medium longevity. N amendments and N-rich barn emissions were found to hasten medium decay. By identifying decay rates and rate predictors specific for biofilter media, we provide biofilter engineers and farmers with a quantitative way to improve medium selection based on the trade-offs between medium cost and replacement frequency.

  17. Impact of water boundary layer diffusion on the nitrification rate of submerged biofilter elements from a recirculating aquaculture system.

    PubMed

    Prehn, Jonas; Waul, Christopher K; Pedersen, Lars-Flemming; Arvin, Erik

    2012-07-01

    Total ammonia nitrogen (TAN) removal by microbial nitrification is an essential process in recirculating aquaculture systems (RAS). In order to protect the aquatic environment and fish health, it is important to be able to predict the nitrification rates in RAS's. The aim of this study was to determine the impact of hydraulic film diffusion on the nitrification rate in a submerged biofilter. Using an experimental batch reactor setup with recirculation, active nitrifying biofilter units from a RAS were exposed to a range of hydraulic flow velocities. Corresponding nitrification rates were measured following ammonium chloride, NH₄Cl, spikes and the impact of hydraulic film diffusion was quantified. The nitrification performance of the tested biofilter could be significantly increased by increasing the hydraulic flow velocity in the filter. Area based first order nitrification rate constants ranged from 0.065 m d⁻¹ to 0.192 m d⁻¹ for flow velocities between 2.5 m h⁻¹ and 40 m h⁻¹ (18 °C). This study documents that hydraulic film diffusion may have a significant impact on the nitrification rate in fixed film biofilters with geometry and hydraulic flows corresponding to our experimental RAS biofilters. The results may thus have practical implications in relation to the design, operational strategy of RAS biofilters and how to optimize TAN removal in fixed film biofilter systems. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Role of Thiobacillus thioparus in the biodegradation of carbon disulfide in a biofilter packed with a recycled organic pelletized material.

    PubMed

    Prenafeta-Boldú, Francesc X; Rojo, Naiara; Gallastegui, Gorka; Guivernau, Miriam; Viñas, Marc; Elías, Ana

    2014-07-01

    This study reports the biodegradation of carbon disulfide (CS2) in air biofilters packed with a pelletized mixture of composted manure and sawdust. Experiments were carried out in two lab-scale (1.2 L) biofiltration units. Biofilter B was seeded with activated sludge enriched previously on CS2-degrading biomass under batch conditions, while biofilter A was left as a negative inoculation control. This inoculum was characterized by an acidic pH and sulfate accumulation, and contained Achromobacter xylosoxidans as the main putative CS2 biodegrading bacterium. Biofilter operation start-up was unsuccessfully attempted under xerophilic conditions and significant CS2 elimination was only achieved in biofilter A upon the implementation of an intermittent irrigation regime. Sustained removal efficiencies of 90-100 % at an inlet load of up to 12 g CS2 m(-3) h(-1) were reached. The CS2 removal in this biofilter was linked to the presence of the chemolithoautotrophic bacterium Thiobacillus thioparus, known among the relatively small number of species with a reported capacity of growing on CS2 as the sole energy source. DGGE molecular profiles confirmed that this microbe had become dominant in biofilter A while it was not detected in samples from biofilter B. Conventional biofilters packed with inexpensive organic materials are suited for the treatment of low-strength CS2 polluted gases (IL <12 g CS2 m(-3) h(-1)), provided that the development of the adequate microorganisms is favored, either upon enrichment or by inoculation. The importance of applying culture-independent techniques for microbial community analysis as a diagnostic tool in the biofiltration of recalcitrant compounds has been highlighted.

  19. Kinetic behaviors between acetone and composite bead in biofilter.

    PubMed

    Chan, Wu-Chung; Chang, Liang-Yuan

    2006-08-01

    In this study, the kinetic behaviors between acetone and composite bead were investigated. The microbial growth rate decreased with increasing average inlet concentration and increased with increasing operation temperature at average inlet concentration ranging from 50 to 300 ppm and operation temperature ranging from 30 to 40 degrees C. The microbial growth rate would be inhibited with increasing average inlet concentration, and the inhibitive effect was more pronounced at higher operation temperature. The microbial growth rate would be enhanced with increasing operation temperature, and the enhancing effect was more pronounced at higher average inlet concentration. The values of maximum reaction rate Vm and half-saturation constant Ks ranged from 0.04 to 0.05 g-C/h-kg packing material and from 37.19 to 42.77 ppm, respectively. The biochemical reaction model could be regarded as the zero-order kinetic with the diffusion rate limitation. The biochemical reaction rate decreased with increasing average inlet concentration and increased with increasing operation temperature. The biochemical reaction rate would be inhibited with increasing average inlet concentration, and the inhibitive effect was more pronounced at lower operation temperature. The biochemical reaction rate would be enhanced with increasing the operation temperature, and the enhancing effect was more pronounced at higher average inlet concentration. The maximum elimination capacity of biofilter increased with increasing operation temperature. The values of critical and maximum elimination capacity ranged from 0.07 to 0.15 and from 0.13 to 0.16 g-C/h-kg packing material, respectively.

  20. Biofiltration of ketone compounds by a composite bead biofilter.

    PubMed

    Chan, Wu-Chung; Peng, Kang-Hong

    2008-05-01

    In this study, the biochemical kinetic behaviors of ketone compounds in a composite bead biofilter were investigated. Both microbial growth rate kg and biochemical reaction rate kd would be inhibited at higher average inlet concentration. For the microbial growth process, the inhibitive effect was the least pronounced for acetone and the order of kg value was MEK>MIPK>acetone in the average inlet concentration range of 100-150 ppm. The degree of inhibitive effect was almost the same for three ketone compounds and the order of kg value was acetone>MEK>MIPK in the average inlet concentration range of 200-300 ppm. The values of half-saturation constant Ks for acetone, MEK and MIPK were 26.80, 21.56 and 22.96 ppm, respectively. The values of maximum reaction rate Vm for acetone, MEK and MIPK were 8.55, 9.06 and 7.55 g-C/h-kg packed material, respectively. The zero-order kinetic with the diffusion rate limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the inhibitive effect was the most pronounced for MEK and the order of kd value was MEK>acetone>MIPK in the average inlet concentration range of 100-150 ppm. The degree of inhibitive effect was MIPK>MEK>acetone and the order of kd value was acetone>MEK>MIPK in the average inlet concentration range of 200-300 ppm. The maximum elimination capacity of acetone, MEK and MIPK were 0.157, 0.127 and 0.101 g-C/h-kg packed material.

  1. [Removal characteristics of DCM by biotrickling filter and biofilter].

    PubMed

    Pan, Wei-Long; Yu, Jian-Ming; Cheng, Zhuo-Wei; Cai, Wen-Ji

    2013-12-01

    A biofilter (BF) packed with nutrition slow-release material and a biotrickling filter (BTF) packed with ether-based polyurethane foam were set up to remove dichloromethane (DCM) from exhaust gas. Results showed that the biofilm formations in BTF and BF were completed by using the mixture of a special strain and a bacterial community, within 25d and 22d, respectively. Through the observation of the filter surface by SEM, the surface of packings in BF was loose with thin biofilm colonies, whereas the one in BTF was dense with thick biofilm. Under the condition of inlet DCM concentration of 100-1,500 mg x m(-3), EBRT of 25-85 s, the removal efficiency of DCM in BTF was better than that in BF, and the maximum removal load was 22.61 g x (m3 x h)(-1) and 29.05 g (m3 x h)(-1), respectively. The relationship between CO2 production and DCM removal was approximately linear, with the mineralization rate being 70.4% and 66.8% for BTF and BF, respectively. The dynamic behaviors of DCM in BTF and BF were described by the Michaelis-Menten model. Through the calculation, the unit volume maximum degradation rate r(max) was 22.7790 g x (m3 x h)(-1) and 28.5714 g x (m3 x h)(-1), while the gas phase saturation constant Ks was 0.1412 g x m(-3) and 0.1486 g x m(-3)

  2. Study of extracellular polymeric substances in the biofilms of a suspended biofilter for nitric oxide removal.

    PubMed

    Li, Han; Huang, Shaobin; Zhou, Shaofeng; Chen, Pengfei; Zhang, Yongqing

    2016-11-01

    The extraction and quantitative analysis of extracellular polymeric substances (EPS) have been frequently reported in studies of activated sludge. However, little is currently known about the EPS in the biofilms of biofilter systems. This study investigates the EPS in biofilms of Chelatococcus daeguensis TAD1 established in a suspended biofilter for nitric oxide (NO) removal under thermophilic conditions. Polysaccharide was the main EPS component under all experimental operation conditions of the aerobic biofilter, although the EPS contents and components varied under different operating conditions. As the concentration of the inlet NO varied from 200 to 2000 mg/m(3), the EPS and protein contents generally increased. At the highest inlet concentration (2000 mg/m(3)), the EPS and protein contents reached 0.118 and 0.055 mg/g, respectively (representing increases of 7.3 and 35 %, respectively, over the inlet concentration of 200 mg/m(3)). In contrast, the polysaccharide content was quite stable against inlet NO concentration. Decreasing the empty bed residence time increased the EPS and polysaccharide contents, but exerted little effect on the protein content. Varying the pH of the circulating fluid from 4 to 8 changed the EPS and its components in complex ways. We also found a strong correlation between the total EPS content and the NO removal efficiency. Therefore, it is possible to take EPS into consideration for biofilter control.

  3. Carbonyl sulfide removal with compost and wood chip biofilters, and in the presence of hydrogen sulfide.

    PubMed

    Sattler, Melanie L; Garrepalli, Divya R; Nawal, Chandraprakash S

    2009-12-01

    Carbonyl sulfide (COS) is an odor-causing compound and hazardous air pollutant emitted frequently from wastewater treatment facilities and chemical and primary metals industries. This study examined the effectiveness of biofiltration in removing COS. Specific objectives were to compare COS removal efficiency for various biofilter media; to determine whether hydrogen sulfide (H2S), which is frequently produced along with COS under anaerobic conditions, adversely impacts COS removal; and to determine the maximum elimination capacity of COS for use in biofilter design. Three laboratory-scale polyvinyl chloride biofilter columns were filled with up to 28 in. of biofilter media (aged compost, fresh compost, wood chips, or a compost/wood chip mixture). Inlet COS ranged from 5 to 46 parts per million (ppm) (0.10-9.0 g/m3 hr). Compost and the compost/wood chip mixture produced higher COS removal efficiencies than wood chips alone. The compost and compost/wood chip mixture had a shorter stabilization times compared with wood chips alone. Fresh versus aged compost did not impact COS removal efficiency. The presence of H2S did not adversely impact COS removal for the concentration ratios tested. The maximum elimination capacity is at least 9 g/m3 hr for COS with compost media.

  4. High performance of nitrogen and phosphorus removal in an electrolysis-integrated biofilter.

    PubMed

    Gao, Y; Xie, Y W; Zhang, Q; Yu, Y X; Yang, L Y

    A novel electrolysis-integrated biofilter system was developed in this study to evaluate the intensified removal of nitrogen and phosphorus from contaminated water. Two laboratory-scale biofilter systems were established, one with electrolysis (E-BF) and one without electrolysis (BF) as control. The dynamics of intensified nitrogen and phosphorus removal and the changes of inflow and outflow water qualities were also evaluated. The total nitrogen (TN) removal rate was 94.4% in our newly developed E-BF, but only 74.7% in the control BF. Ammonium removal rate was up to 95% in biofilters with or without electrolysis integration with an influent ammonium concentration of 40 mg/L, and the accumulation of nitrate and nitrite was much lower in the effluent of E-BF than that of BF. Thus electrolysis plays an important role in TN removal especially the nitrate and nitrite removal. Phosphorus removal was significantly enhanced, exceeding 90% in E-BF by chemical precipitation, physical adsorption, and flocculation of phosphorus because of the in situ formation of ferric ions by the anodizing of sacrificial iron anodes. Results from this study indicate that the electrolysis integrated biofilter is a promising solution for intensified nitrogen and phosphorus removal.

  5. Biofiltration of Chloroform in a Trickle Bed Air Biofilter Under Acidic Conditions

    EPA Science Inventory

    In this paper, the application of biofiltration is investigated for controlled removal of gas phase chloroform through cometabolic degradation with ethanol. A trickle bed air biofilter (TBAB) operated under acidic pH 4 is subjected to aerobic biodegradation of chloroform and etha...

  6. Biological vapor-phase treatment using biofilter and biotrickling filter reactors: Practical operating regimes

    SciTech Connect

    Togna, A.P.; Singh, M. )

    1994-05-01

    The biological treatment of volatile organic compounds (VOCs) and air toxics has received increased attention in recent years. Biotreatment of airborne contaminants offers an inexpensive alternative to conventional air treatment technologies such as carbon adsorption and incineration. Most biological air treatment technologies commercially available are fixed-film systems that rely on growth of a biofilm layer on an inert organic support such as compost or peat (biofilters), or an inorganic support such as ceramic or plastic (biotrickling filters). If designed properly, these systems combine the advantages of high biomass concentration with high specific surface area for mass transfer. At economically viable vapor residence times (1 to 1.5 minutes), biofilters can be used for treating vapor streams containing up to approximately 1500 [mu]g/L of readily biodegradable compounds. Biotrickling filters may offer greater performance than biofilters at high contaminant loadings, possibly due to higher internal biomass concentrations. Both systems are best suited for treating vapor streams containing one or two major compounds. If designed properly, biofilters are especially well suited for treating streams that vary in concentration from minute to minute. 11 refs., 8 figs.

  7. EVALUATION OF TRICKLE-BED AIR BIOFILTER PERFORMANCE FOR STYRENE REMOVAL

    EPA Science Inventory

    A pilot-scale trickle-bed air biofilter (TBAB) was evaluated for the removal of styrene from a waste gas stream. Six-millimeter (6 mm) Celite pellets (R-635) were used as the biological attachment medium. The operating parameters considered in the study included the styrene vol...

  8. Hexane abatement and spore emission control in a fungal biofilter-photoreactor hybrid unit.

    PubMed

    Saucedo-Lucero, J O; Quijano, G; Arriaga, S; Muñoz, R

    2014-07-15

    The performance of a fungal perlite-based biofilter coupled to a post-treatment photoreactor was evaluated over 234 days in terms of n-hexane removal, emission and deactivation of fungal spores. The biofilter and photoreactor were operated at gas residence times of 1.20 and 0.14min, respectively, and a hexane loading rate of 115±5gm(-3)h(-1). Steady n-hexane elimination capacities of 30-40gm(-3)h(-1) were achieved, concomitantly with pollutant mineralization efficiencies of 60-90%. No significant influence of biofilter irrigation frequency or irrigation nitrogen concentration on hexane abatement was recorded. Photolysis did not support an efficient hexane post-treatment likely due to the short EBRT applied in the photoreactor, while overall hexane removal and mineralization enhancements of 25% were recorded when the irradiated photoreactor was packed with ZnO-impregnated perlite. However, a rapid catalyst deactivation was observed, which required a periodic reactivation every 48h. Biofilter irrigation every 3 days supported fungal spore emissions at concentrations ranging from 2.4×10(3) to 9.0×10(4)CFUm(-3). Finally, spore deactivation efficiencies of ≈98% were recorded for the photolytic and photocatalytic post-treatment processes. This study confirmed the potential of photo-assisted post-treatment processes to mitigate the emission of hazardous fungal spores and boost the abatement performance of biotechnologies. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Investigation into the aerodynamic processes of air treatment using a plate-type biofilter.

    PubMed

    Baltrėnas, Pranas; Kleiza, Jonas; Idzelis, Raimondas Leopoldas

    2016-01-01

    The research conducted has involved a laboratory stand of a plate-type air treatment biofilter with a capillary system for humidifying packing material composed of polymer plates vertically arranged next to each other and producing a capillary effect of humidification. The pattern of arranging the plates has sufficiently large spaces (6 mm), and therefore the use of the plate-type structure decreases the aerodynamic resistance of the device. Slightly pressed slabs attached on both sides of the plates are made of heat-treated wood fibre, to increase the longevity of which, wood waste has been heat-treated in the steam explosion reactor under the pressure of 32 bars and a temperature of 235 °C. This is the method for changing the molecular structure of wood, which stops the decay of wood fibre in a humid environment and thus increases the life span of biofilter plates. The research performed has disclosed that, under the application of the above introduced structure of the biofilter, the aerodynamic resistance of the biofilter reaches 1 ÷ 5 Pa when the rate of the air flow passing through the device makes 0.08 m/s. For evaluating the reliability of the obtained results, the theoretical model has been applied.

  10. Potential application of an Aspergillus strain in a pilot biofilter for benzene biodegradation

    PubMed Central

    Sun, Da; Zhang, Kun; Duan, Chuanren; Wu, Wei; Deng, Daiyong; Yu, Donghong; Shahzad, M. Babar; Xu, Dake; Tang, Ju; Luo, Li; Chen, Jia; Wang, Jinxuan; Chen, Yidan; Xie, Xiang; Wang, Guixue

    2017-01-01

    A biofilter with fungus was developed for efficient degradation of benzene, which can overcome the potential risk of leakage commonly found in such services. Results indicated that the optimum parameter values were temperature 40 °C, pH 6, and 500 mg L−1 of the initial benzene concentration. Besides, the empty bed residence time and inlet load range of biofilter were set to 20 s and 21.23–169.84 g m−3 h−1 respectively. Under these conditions, this biofilter can obtain the maximum removal efficiency of more than 90%, the eliminating capacity could be up to 151.67 g m−3 h−1. Furthermore, scanning electron microscopy was used to investigate three filler materials for packing fungus biofilm. This is the first study introducing an Aspergillus strain for benzene removal and these results highlight that the development of this biofilter has the potential scaling-up application as gas-processing of industrial wastes. PMID:28383064

  11. Livestock Air Treatment Using PVA-Coated Powdered Activated Carbon Biofilter

    USDA-ARS?s Scientific Manuscript database

    Ideal biofilter media provide surface for attachment of microorganisms responsible for removing air-born contaminants while facilitating passage of air. This study evaluated the efficacy of polyvinyl alcohol (PVA)-coated powdered activated carbon particles as a biofiltration medium. This material e...

  12. Removal of dichloromethane from waste gas streams using a hybrid bubble column/biofilter bioreactor

    PubMed Central

    2014-01-01

    The performance of a hybrid bubble column/biofilter (HBCB) bioreactor for the removal of dichloromethane (DCM) from waste gas streams was studied in continuous mode for several months. The HBCB bioreactor consisted of two compartments: bubble column bioreactor removing DCM from liquid phase and biofilter removing DCM from gas phase. Effect of inlet DCM concentration on the elimination capacity was examined in the DCM concentration range of 34–359 ppm with loading rates ranged from 2.2 to 22.8 g/m3.h and constant total empty bed retention time (EBRT) of 200 s. In the equal loading rates, the elimination capacity and removal efficiency of the biofilter were higher than the corresponding values of the bubble column bioreactor. The maximum elimination capacity of the HBCB bioreactor was determined to be 15.7 g/m3.h occurred in the highest loading rate of 22.8 g/m3.h with removal efficiency of 69%. The overall mineralization portion of the HBCB bioreactor was in the range of 72-79%. The mixed liquor acidic pH especially below 5.5 inhibited microbial activity and decreased the elimination capacity. Inhibitory effect of high ionic strength was initiated in the mixed liquor electrical conductivity of 12.2 mS/cm. This study indicated that the HBCB bioreactor could benefit from advantages of both bubble column and biofilter reactors and could remove DCM from waste gas streams in a better manner. PMID:24406056

  13. Modelling and computational fluid dynamic behaviour of a biofilter treating benzene.

    PubMed

    Rahul; Mathur, Anil Kumar; Bala, Shashi; Majumder, Chandrajitbalo

    2012-12-01

    Biofiltration of an air stream containing benzene has been studied in a laboratory biofilter packed with a mixture of compost, sugar cane bagasse and GAC. In this study, the overall performance of a biofilter has been evaluated in terms of its elimination capacity by using 3-D mesh techniques. The overall results indicate that the agreement between experimental data and estimated model predictions is excellent for benzene. The benzene concentration profiles along the depth of biofilter have also been determined using a convection-diffusion reactor (CDR) model and computational fluid dynamic (CFD) technique. At low flow rates and low concentrations of benzene, the concentration profile throughout the biofilter shows good agreement with CDR model and it becomes more curved and resembles typical decay. Combined analysis of experimental results with CDR model and the CFD shows that the profile of benzene at low concentration becomes more curved and then linear at high concentration. The benzene profiles obtained by CFD are within 5% accuracy of experimental results. The CDR and CFD models are found to be able to predict concentration profiles preciously with depth under the experimental conditions. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  14. Air purification from TCE and PCE contamination in a hybrid bioreactors and biofilter integrated system.

    PubMed

    Tabernacka, Agnieszka; Zborowska, Ewa; Lebkowska, Maria; Borawski, Maciej

    2014-01-15

    A two-stage waste air treatment system, consisting of hybrid bioreactors (modified bioscrubbers) and a biofilter, was used to treat waste air containing chlorinated ethenes - trichloroethylene (TCE) and tetrachloroethylene (PCE). The bioreactor was operated with loadings in the range 0.46-5.50gm(-3)h(-1) for TCE and 2.16-9.02gm(-3)h(-1) for PCE. The biofilter loadings were in the range 0.1-0.97gm(-3)h(-1) for TCE and 0.2-2.12gm(-3)h(-1) for PCE. Under low pollutant loadings, the efficiency of TCE elimination was 23-25% in the bioreactor and 54-70% in the biofilter. The efficiency of PCE elimination was 44-60% in the bioreactor and 50-75% in the biofilter. The best results for the bioreactor were observed one week after the pollutant loading was increased. However, the process did not stabilize. In the next seven days contaminant removal efficiency, enzymatic activity and biomass content were all diminished. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Potential application of an Aspergillus strain in a pilot biofilter for benzene biodegradation.

    PubMed

    Sun, Da; Zhang, Kun; Duan, Chuanren; Wu, Wei; Deng, Daiyong; Yu, Donghong; Shahzad, M Babar; Xu, Dake; Tang, Ju; Luo, Li; Chen, Jia; Wang, Jinxuan; Chen, Yidan; Xie, Xiang; Wang, Guixue

    2017-04-06

    A biofilter with fungus was developed for efficient degradation of benzene, which can overcome the potential risk of leakage commonly found in such services. Results indicated that the optimum parameter values were temperature 40 °C, pH 6, and 500 mg L(-1) of the initial benzene concentration. Besides, the empty bed residence time and inlet load range of biofilter were set to 20 s and 21.23-169.84 g m(-3) h(-1) respectively. Under these conditions, this biofilter can obtain the maximum removal efficiency of more than 90%, the eliminating capacity could be up to 151.67 g m(-3) h(-1). Furthermore, scanning electron microscopy was used to investigate three filler materials for packing fungus biofilm. This is the first study introducing an Aspergillus strain for benzene removal and these results highlight that the development of this biofilter has the potential scaling-up application as gas-processing of industrial wastes.

  16. Removal of dichloromethane from waste gas streams using a hybrid bubble column/biofilter bioreactor.

    PubMed

    Abtahi, Mehrnoosh; Naddafi, Kazem; Mesdaghinia, Alireza; Yaghmaeian, Kamyar; Nabizadeh, Ramin; Jaafarzadeh, Nematollah; Rastkari, Noushin; Nazmara, Shahrokh; Saeedi, Reza

    2014-01-09

    The performance of a hybrid bubble column/biofilter (HBCB) bioreactor for the removal of dichloromethane (DCM) from waste gas streams was studied in continuous mode for several months. The HBCB bioreactor consisted of two compartments: bubble column bioreactor removing DCM from liquid phase and biofilter removing DCM from gas phase. Effect of inlet DCM concentration on the elimination capacity was examined in the DCM concentration range of 34-359 ppm with loading rates ranged from 2.2 to 22.8 g/m3.h and constant total empty bed retention time (EBRT) of 200 s. In the equal loading rates, the elimination capacity and removal efficiency of the biofilter were higher than the corresponding values of the bubble column bioreactor. The maximum elimination capacity of the HBCB bioreactor was determined to be 15.7 g/m3.h occurred in the highest loading rate of 22.8 g/m3.h with removal efficiency of 69%. The overall mineralization portion of the HBCB bioreactor was in the range of 72-79%. The mixed liquor acidic pH especially below 5.5 inhibited microbial activity and decreased the elimination capacity. Inhibitory effect of high ionic strength was initiated in the mixed liquor electrical conductivity of 12.2 mS/cm. This study indicated that the HBCB bioreactor could benefit from advantages of both bubble column and biofilter reactors and could remove DCM from waste gas streams in a better manner.

  17. Performance evaluation and model analysis of BTEX contaminated air in corn-cob biofilter system.

    PubMed

    Rahul; Mathur, Anil Kumar; Balomajumder, Chandrajit

    2013-04-01

    Biofiltration of BTEX with corn-cob packing material have been performed for a period of 68 days in five distinct phases. The overall performance of a biofilter has been evaluated in terms of its elimination capacity by using 3-D mesh techniques. Maximum removal efficiency was found more than 99.85% of all four compounds at an EBRT of 3.06 min in phase I for an inlet BTEX concentration of 0.0970, 0.0978, 0.0971 and 0.0968 g m(-3), respectively. Nearly 100% removal achieved at average BTEX loadings of 20.257 g m(-3) h(-1) to biofilter. A maximum elimination capacity (EC) of 20.239 g m(-3) h(-1) of the biofilter was obtained at inlet BTEX load of 20.391 g m(-3) h(-1). Moreover, using convection-diffusion reaction (CDR) model for biofilter depth shows good agreement with the experimental values for benzene, toluene and ethyl benzene, but for o-xylene the model results deviated from the experimental. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Extended operation and control of biomass overgrowth in biofilters designed for VOC removal

    SciTech Connect

    Barton, J.W.; Klasson, K.T.; Davison, B.H.

    1997-12-31

    Biofiltration systems have been applied in several industries for treatment of volatile organic compounds (VOCs); however, the systems are poorly understood and are generally implemented as black boxes. Common operational problems associated with biofilters include fouling, deactivation, and overgrowth, all of which make biofilters ineffective for continuous long-term use. The objective of this investigation was to develop generic methods for long-term stable operation, in particular by using selective limitation of supplemental nutrients while maintaining high activity and the ability to regenerate biofilter activity. Sustained degradation rates of approximately 50 g/h/m{sup 3} for isobutane and n-pentane in air (5,000 ppm) were maintained in a trickle bed bioreactor for over 12 months using a nutrient-limited liquid recycle stream. After 5 to 6 months of operation, rates quickly declined to less than 10 g/h/m{sup 3}, presumably due to extended supplemental nutrient depletion. At this time, the limiting nutrient was reintroduced into the liquid stream and previous removal rates were restored in less than two weeks. Furthermore, biological and transport fundamentals (kinetics and mass transfer) were successfully incorporated into a steady state mathematical model in order to successfully predict operating parameters and thus enable better design. Advances in these areas are particularly important for implementation and extended activity of biofilters in industrial settings and are directly relevant for high priority contaminants.

  19. Escherichia coli Removal in Biochar-Modified Biofilters: Effects of Biofilm.

    PubMed

    Afrooz, A R M Nabiul; Boehm, Alexandria B

    2016-01-01

    The presence of microbial contaminants in urban stormwater is a significant concern for public health; however, their removal by traditional stormwater biofilters has been reported as inconsistent and inadequate. Recent work has explored the use of biochar to improve performance of stormwater biofilters under simplified conditions that do not consider potential effects of biofilm development on filter media. The present study investigates the role of biofilm on microbial contaminant removal performance of stormwater biofilters. Pseudomonas aeruginosa biofilms were formed in laboratory-scale sand and biochar-modified sand packed columns, which were then challenged with Escherichia coli laden synthetic stormwater containing natural organic matter. Results suggests that the presence of biofilm influences the removal of E. coli. However, the nature of the influence depends on the specific surface area and the relative hydrophobicity of filter media. The distribution of attached bacteria within the columns indicates that removal by filter media varies along the length of the column: the inlet was the primary removal zone regardless of experimental conditions. Findings from this research inform the design of field-scale biofilters for better and consistent performance in removing microbial contaminants from urban stormwater.

  20. EVALUATION OF BIOAEROSOL EXPOSURES DURING CONDITIONING OF BIOFILTER ORGANIC MEDIA BEDS

    EPA Science Inventory

    Biological media air filters (biofilters) are currently being used for the treatment of inorganic and organic gasses from sewage treatment plants, industrial processes, and remediation systems. The media may be organic material such as comost, wood chips, or synthetic plastic med...

  1. EVALUATION OF TRICKLE-BED AIR BIOFILTER PERFORMANCE FOR STYRENE REMOVAL

    EPA Science Inventory

    A pilot-scale trickle-bed air biofilter (TBAB) was evaluated for the removal of styrene from a waste gas stream. Six-millimeter (6 mm) Celite pellets (R-635) were used as the biological attachment medium. The operating parameters considered in the study included the styrene vol...

  2. EVALUATION OF BIOAEROSOL EXPOSURES DURING CONDITIONING OF BIOFILTER ORGANIC MEDIA BEDS

    EPA Science Inventory

    Biological media air filters (biofilters) are currently being used for the treatment of inorganic and organic gasses from sewage treatment plants, industrial processes, and remediation systems. The media may be organic material such as comost, wood chips, or synthetic plastic med...

  3. Fluidization velocity assessment of commercially available sulfur particles for use in autotrophic denitrification biofilters

    USDA-ARS?s Scientific Manuscript database

    There has been no evaluation of sulfur-based autotrophic denitrification using fluidized biofilters in a recirculating aquaculture system to mitigate nitrate-nitrogen loads. The objectives of this work were to quantify the particle size distribution, specific surface area, and fluidization velocitie...

  4. Laboratory study on factors influencing nitrogen removal in marble chip biofilters incorporating nitritation and anammox.

    PubMed

    Tao, Wendong; Wen, Jianfeng; Norton, Christopher

    2011-01-01

    It remains challenging to integrate nitritation and anammox in ecologically engineered treatment systems such as passive biofilters that are packed with natural materials and have low energy inputs. This study explored the factors influencing nitritation-anammox through parallel operation of two laboratory-scale biofilters packed with large and small marble chips respectively. Clean marble chips (mainly CaCO3) had an alkalinity dissolution rate of 130 mg CaCO3/kg marble d when water pH approached 6.5. Marble chips effectively increased water pH and provided sufficient alkalinity to support nitritation-anammox in the biofilters. Ammonium and total nitrogen removal decreased by 47 and 26%, respectively, when nutrients were not amended to influent. An influent nitrite concentration above 8.9 mg N/L could inhibit anammox in thin biofilms of biofilters. Nitritation-anammox was enhanced with a hydraulic retention time of 2 d relative to 7 d, likely due to enhanced air entrainment. Size of marble chips rarely made a significant difference in nitrogen removal, possibly due to sufficient surface area available for bacterial attachment and alkalinity dissolution.

  5. Biofiltration of Chloroform in a Trickle Bed Air Biofilter Under Acidic Conditions

    EPA Science Inventory

    In this paper, the application of biofiltration is investigated for controlled removal of gas phase chloroform through cometabolic degradation with ethanol. A trickle bed air biofilter (TBAB) operated under acidic pH 4 is subjected to aerobic biodegradation of chloroform and etha...

  6. Escherichia coli Removal in Biochar-Modified Biofilters: Effects of Biofilm

    PubMed Central

    Afrooz, A. R. M. Nabiul; Boehm, Alexandria B.

    2016-01-01

    The presence of microbial contaminants in urban stormwater is a significant concern for public health; however, their removal by traditional stormwater biofilters has been reported as inconsistent and inadequate. Recent work has explored the use of biochar to improve performance of stormwater biofilters under simplified conditions that do not consider potential effects of biofilm development on filter media. The present study investigates the role of biofilm on microbial contaminant removal performance of stormwater biofilters. Pseudomonas aeruginosa biofilms were formed in laboratory-scale sand and biochar-modified sand packed columns, which were then challenged with Escherichia coli laden synthetic stormwater containing natural organic matter. Results suggests that the presence of biofilm influences the removal of E. coli. However, the nature of the influence depends on the specific surface area and the relative hydrophobicity of filter media. The distribution of attached bacteria within the columns indicates that removal by filter media varies along the length of the column: the inlet was the primary removal zone regardless of experimental conditions. Findings from this research inform the design of field-scale biofilters for better and consistent performance in removing microbial contaminants from urban stormwater. PMID:27907127

  7. Potential application of an Aspergillus strain in a pilot biofilter for benzene biodegradation

    NASA Astrophysics Data System (ADS)

    Sun, Da; Zhang, Kun; Duan, Chuanren; Wu, Wei; Deng, Daiyong; Yu, Donghong; Shahzad, M. Babar; Xu, Dake; Tang, Ju; Luo, Li; Chen, Jia; Wang, Jinxuan; Chen, Yidan; Xie, Xiang; Wang, Guixue

    2017-04-01

    A biofilter with fungus was developed for efficient degradation of benzene, which can overcome the potential risk of leakage commonly found in such services. Results indicated that the optimum parameter values were temperature 40 °C, pH 6, and 500 mg L-1 of the initial benzene concentration. Besides, the empty bed residence time and inlet load range of biofilter were set to 20 s and 21.23-169.84 g m-3 h-1 respectively. Under these conditions, this biofilter can obtain the maximum removal efficiency of more than 90%, the eliminating capacity could be up to 151.67 g m-3 h-1. Furthermore, scanning electron microscopy was used to investigate three filler materials for packing fungus biofilm. This is the first study introducing an Aspergillus strain for benzene removal and these results highlight that the development of this biofilter has the potential scaling-up application as gas-processing of industrial wastes.

  8. Biodegradation of gaseous toluene with mixed microbial consortium in a biofilter: steady state and transient operation.

    PubMed

    Rajamanickam, Ravi; Baskaran, Divya

    2017-09-04

    Petroleum oil refineries are massive emitters of risky volatile organic compounds (VOCs). Among the VOCs, toluene is taken into account as a significant pollutant. In the present study, a compost biofilter is used to treat the toluene vapor. However, an elimination capacity and removal efficiency of the biofilter was investigated for a wide range of toluene concentrations (0.29-3.8 g m(-3)) and operated for 54 days effectively. Elimination capacity of 93 g m(-3) h(-1) was recorded as maximum value at a toluene inlet concentration of 114 g m(-3) h(-1). An elimination capacity was perpetually better at the lower section of the biofilter, and therefore, the value was around 40-60 g m(-3) h(-1). The high removal efficiency of 97% was obtained at inlet toluene load of 60.55 g m(-3) h(-1). Hence, the biofilm was quite sensitive to handling transient loading conditions. The pressure drop had no vital impact on the biofilter performance. An Ottengraf model was applied to all phase of biofilter operation in each of the diffusion limiting region and reaction limiting region. The parameters of the model K 1 (75.95 g(1/2) m(-3/2) h(-1)) and K 0 (90.51 g m(-3) h(-1)) were obtained from diffusion and reaction limiting region severally. However, K 1 was used to calculate the theoretical elimination capacities, and therefore, K 0 was used to discover the biofilm thickness. By the way, the average biofilm thickness was found to be 0.98 mm from reaction limiting region.

  9. The Application Of Biofilter System For Reduction Of Methane Emissions From Modern Sanitary Landfills

    NASA Astrophysics Data System (ADS)

    Sung, K.; Park, S.

    2007-12-01

    Increased atmospheric concentrations of greenhouse gases (GHG) caused by anthropogenic activities has been related to global climate change. Methane, the second most important GHG after CO2, is 21 times more effective at trapping heat than CO2. Therefore, methane emission control is of utmost importance for global warming reduction. To minimize leachate production and protect groundwater resources, modern sanitary landfills are equipped with composite covers and gas collection systems. Methane from modern sanitary landfills is vented directly to the atmosphere, except for some of the largest landfills where it is recovered as energy and burned at the site. However, the efficiency of energy recovery systems in larger landfills is reduced as the amount of CH4 generated from landfill begins to decrease. In this study, the performance of a lab-scale model biofilter system was investigated to treat CH4 gas emitted from modern sanitary landfills by conducting batch and column experiments using landfill cover soil amended with earthworm cast as the filter bed medium. From the batch experiments to measure the influence of moisture content and temperature of the filter medium on CH4 removal capacity of a biofilter system, the optimum moisture content and temperature were found to be 10-15% by weight and 25-35°C, respectively. The column experiment was conducted to measure the influence of inlet CH4 concentration and CH4 loading rate on CH4 removal capacity of a biofilter system. As the inlet CH4 concentration decreased, the percentage of CH4 oxidized increased. Up to a CH4 loading rate of 2785 g CH4 m3 h- 1 (EBRT = 7.7 min), the CH4 removal efficiency of the biofilter was able to reach 100%. Based on the results of the study, the installation of a properly managed biofilter system should be capable of achieving a reduction in atmospheric CH4 emissions from modern sanitary landfills at low CH4 generation stage.

  10. The use of novel packing material for improving methane oxidation in biofilters.

    PubMed

    Brandt, Emanuel Manfred F; Duarte, Felipe V; Vieira, João Paulo R; Melo, Vinícius M; Souza, Cláudio L; Araújo, Juliana C; Chernicharo, Carlos Augusto L

    2016-11-01

    The use of biofilters (working bed volume of 7.85 L) for the oxidation of CH4 at low concentrations (from 0.17%v/v to 3.63%v/v, typically in waste gas from anaerobic sewage treatment) was investigated and four empty bed residence times were tested (in min): 42.8, 29.5, 19.6, and 7.4. Mixtures of organic (composted leaves) and three non-organic materials (sponge-based material - SBM, blast furnace slag - BFS, and expanded vermiculite - ExpV) were used as packing media. Along 188 operational days after the steady state was reached (95 days for start-up), the CH4 mineralization decreased while the inlet loads gradually increased from 3.0 ± 0.8 gCH4 m(-3) h(-1) to 148.8 ± 4.4 gCH4 m(-3) h(-1). The biofilter packed with ExpV showed the best results, since the CH4 conversions decreased from 95.0 ± 5.0% to 12.7 ± 3.7% as a function of inlet concentration, compared to the other two biofilters (SBM and BFS) which showed CH4 conversions decreasing from 56.0 ± 5.4% to 3.5 ± 1.2% as a function of inlet concentration. The methanotrophic activity of biomass taken from ExpV biofilter was three times higher than the activity of biomass from the other two biofilters. Taken together, these results suggested that ExpV provides an attractive environment for microbial growth, besides the mechanical resistance provided to the whole packing media, showing the potential to its use in biofiltration of diffuse CH4 emissions.

  11. Removal of Mn2+ from water by "aged" biofilter media: the role of catalytic oxides layers.

    PubMed

    Sahabi, Danladi Mahuta; Takeda, Minoru; Suzuki, Ichiro; Koizumi, Jun-ichi

    2009-02-01

    The present work was aimed at evaluating the surface coatings characteristics and autocatalytic manganese oxidation potentials of two groups of "aged" biofilter media. This refers to the anthracite filter media of a biological water treatment plant on which metal oxides and a biofilm have deposited on the surface of the filter media over long time of filtration. Duplicate samples of anthracite filter media were collected from each of the six filter wells in the plant and classified into two groups, based on their duration of operation, as 3-years filter media and 15-years filter media. Batch experiments showed that the 15-years filter media exhibited very high manganese sorption capacity and were less dependent on the microbial activity than the 3-years filter media. Results of the surface coatings analyses indicated that the biofilter materials is predominantly composed of variable layers of manganese and iron oxides, with microbial biomass contributing only about 3.5 and 1.4% of the dry weight of the surface coatings on the 3- and 15-years filter media respectively. Investigations onto the Mn2+ sorption by the lyophilized biofilter media showed that, the sorption kinetics on the catalytic oxides layers followed the pseudo-second-order kinetics model, thus suggesting chemisorption as the dominant mechanism of Mn2+ removal. This implied that manganese removal by these biofilters is mainly by adsorption of Mn2+ onto the iron and manganese (catalytic) oxides layers and autocatalytic oxidation. The present study has clearly linked Mn2+ oxidation to the catalytic oxides layers on the aged biofilter media.

  12. Modeling of a combined ultraviolet-biofilter system to treat gaseous chlorobenzene I: model development and parametric sensitivity.

    PubMed

    Wang, Can; Xi, Jin-Ying; Hu, Hong-Ying; Kang, In-Sun

    2011-03-01

    A new type of a combined ultraviolet (UV)-biofilter system for air pollution control is developed. In this paper, two conceptual mathematical submodels of the UV reactor and standalone biofilter are developed. All model parameters have been determined by independent experiments or have been taken from literature. Results from UV and the standalone biofilter submodels are in a good agreement with experimental data. However, the performance of the combined system has significantly deviated from those of the UV or standalone submodels because of the stimulating effects of UV irradiation products on the subsequent biofilter performance. A modified model that considers the stimulating effects has agreed well with experimental data over a wide range of operating conditions. Further analysis of the primary parametric sensitivity of the model has shown that inlet chlorobenzene concentrations, gas empty-bed residence time in the UV reactor, and light intensity are important operating conditions.

  13. Re-acclimation performance and microbial characteristics of a thermophilic biofilter for NOx removal from flue gas.

    PubMed

    Zhang, Shihan; Chen, Han; Xia, Yinfeng; Zhao, Jingkai; Liu, Nan; Li, Wei

    2015-08-01

    Currently, a novel chemical absorption-biological reduction (CABR) integrated process, employing Fe(II)EDTA as a solvent, is being under development to reduce the cost of NOx removal from flue gas. In this work, the NO removal profile, re-acclimation performance, and microbial characteristics in a thermophilic biofilter were investigated at the conditions typical to CABR process. The biofilter comprised of four layers of packing material with a surface area of 1200 m(2) m(-3). Experimental results revealed that the biofilter could remove 95 % of the fed NO at typical flue gas conditions. As the gas residence time varied from 90 to 15 s, the NO removal efficiency decreased from 100 to 56.5 % due to the NO mass transfer limitation. The longer period of the biofilter shutdown required more time for its re-acclimation. For example, after 8-day shutdown, the biofilter was re-acclimated in 32 h. Denaturing gradient gel electrophoresis analysis of PCR-amplified product showed that Pseudomonas, a group of denitrifier, was dominant in the biofilter. Because the Pseudomonas was abundant at the bottom layer of packed-bed, the bottom layer contributed to 60-70 % of the total NO removal. In addition, Pseudomonas gradually faded away along the gas flow path from the bottom to the top of biofilter, resulting in a significant decrease in NO removal at the other three packed-bed layers. These observed results will provide the process engineering and scale-up data with respect to the biofilter operations to help advance the CABR process to pilot-scale testing.

  14. Adapting Biofilter Processes to Treat Spray Painting Exhausts: Concentration and Leveling of Vapor Delivery Rates, and Enhancement of Destruction by Exhaust Recirculation

    DTIC Science & Technology

    2001-12-20

    Adapting Biofilter Processes to Treat Spray Painting Exhausts: Concentration and Leveling of Vapor Delivery Rates, and Enhancement of Destruction by...Phase II Final; July 1998–January 2001 4. TITLE AND SUBTITLE Adapting a Biofilter to Treat Spray Painting Exhausts: Concentration and Leveling of...Maximum 200 words) The goal of this Phase II SBIR effort was to demonstrate the compatibility of a concentrator–regenerator coupled with a biofilter

  15. Rudolf Clausius. Ein Versuch, ihn zu verstehen

    NASA Astrophysics Data System (ADS)

    Schöpf, Hans-Georg

    Es wird dargelegt, daß Clausius' Originalarbeiten über die Begründung des zweiten Hauptsatzes schwerlich vom Standpunkt konventioneller Lehrbücher verstanden werden können. Vielmehr erweist sich eine mit einem quasi-ökonomischen Modell arbeitende Denkweise als Schlüssel zum Verständnis.Translated AbstractRudolf Clausius. An Attempt to Understand HimIt is shown that Clausius' original papers on the foundation of the Second Law can scarcely be understood from the view-point of conventional textbooks. But reasoning with the aid of a quasi-economic model turns out to be the key of comprehension.

  16. Effect of advanced oxidants generated via ultraviolet light on a sequentially loaded and regenerated granular activated carbon biofilter.

    PubMed

    Dusenbury, James S; Cannon, Fred S

    2004-07-01

    The objective of this research was to investigate a sequentially loaded and regenerated granular activated carbon (GAC) biofilter system and to determine whether regenerative ozonation/advanced oxidation could improve the removal and biodegradation of a volatile organic compound from a contaminated airstream. Bench-scale reactors were constructed to operate in a manner analogous to a commercially available system manufactured by Terr-Aqua Environmental Systems (only with longer contact time). The GAC system consisted of two GAC biofilter beds that operated in a cyclical manner. On a given day, the first GAC bed adsorbed methyl isobutyl ketone from a simulated waste airstream, while the second bed underwent regeneration; then on the next day, the second bed was in the adsorption mode while the first was regenerated. Three bench-scale systems were used to compare the performance under three operating conditions: (1) ozone/ associated oxidant regeneration of a GAC biofilter system that was seeded with microorganisms from a field site, (2) a humid air regeneration of a seeded GAC biofilter, and (3) a humid air regeneration of an unseeded GAC biofilter. For the advanced oxidant regenerated GAC biofilter, a maximum removal efficiency of >95% was achieved with an empty bed contact time of 148 sec and an influent concentration of 125 ppm methyl isobutyl ketone, and 90-95% was achieved at 148-sec empty bed contact time and a 1150-ppm influent.

  17. Fungal biofilters for toluene biofiltration: evaluation of the performance with four packing materials under different operating conditions.

    PubMed

    Maestre, Juan P; Gamisans, Xavier; Gabriel, David; Lafuente, Javier

    2007-03-01

    Packing materials play a key role in the performance of bioreactors for waste gas treatment and particularly in biofilter applications. In this work, the performance of four differently packed biofilters operated in parallel for the treatment of relatively high inlet concentration of toluene was studied. The reactors were compared for determining the suitability of coconut fiber, digested sludge compost from a waste water treatment plant, peat and pine leaves as packing materials for biofiltration of toluene. A deep characterisation of materials was carried out. Biological activity and packing capabilities related to toluene removal were determined throughout 240 days of operation under different conditions of nutrients addition and watering regime. Also, biofilters recovering after a short shutdown was investigated. Nutrient addition resulted in improved removal efficiencies (RE) and elimination capacities (EC) of biofilters reaching maximum ECs between 75 and 95 g m(-3)h(-1) of toluene. In the first 80 days, the pH decreased progressively within the reactors, causing a population change from bacteria to fungi, which were the predominant decontaminant microorganisms thereafter. All reactors were found to recover the RE rapidly after a 5 days shutdown and, in a maximum of 7 days, all reactors had been completely recuperated. These results point out that fungal biofilters are a suitable choice to treat high loads of toluene. In general, coconut fiber and compost biofilters exhibited a better performance in terms of elimination capacity and long-term stability.

  18. Automatisierte VHDL-Code-Generierung eines Delta-Sigma Modulators

    NASA Astrophysics Data System (ADS)

    Spilka, R.; Ostermann, T.

    2006-09-01

    Im vorliegenden Beitrag wird eine automatische Generierung des VHDL-Codes eines Delta-Sigma Modulators präsentiert. Die Koeffizientenmultiplikation wird hierbei durch Bit-Serielle-Addition durchgeführt. Mit Hilfe zweier neuer Matlab Funktionen wird der Systementwurf durch die bekannte Delta-Sigma Toolbox von R. Schreier erweitert und direkt synthesefähiger VHDL Code erzeugt.

  19. EIN3 and SOS2 synergistically modulate plant salt tolerance

    PubMed Central

    Quan, Ruidang; Wang, Juan; Yang, Dexin; Zhang, Haiwen; Zhang, Zhijin; Huang, Rongfeng

    2017-01-01

    Ethylene biosynthesis and the ethylene signaling pathway regulate plant salt tolerance by activating the expression of downstream target genes such as those related to ROS and Na+/K+ homeostasis. The Salt Overly Sensitive (SOS) pathway regulates Na+/K+ homeostasis in Arabidopsis under salt stress. However, the connection between these two pathways is unclear. Through genetic screening, we identified two sos2 alleles as salt sensitive mutants in the ein3-1 background. Neither Ethylene-Insensitive 2 (EIN2) nor EIN3 changed the expression patterns of SOS genes including SOS1, SOS2, SOS3 and SOS3-like Calcium Binding Protein 8 (SCaBP8), but SOS2 activated the expression of one target gene of EIN3, Ethylene and Salt-inducible ERF 1 (ESE1). Moreover, Ser/Thr protein kinase SOS2 phosphorylated EIN3 in vitro mainly at the S325 site and weakly at the S35, T42 and S606 sites. EIN3 S325A mutation reduced its transcriptional activating activity on ESE1 promoter:GUS in a transient GUS assay, and impaired its ability to rescue ein3-1 salt hypersensitivity. Furthermore, SOS2 activated salt-responsive ESE1 target gene expression under salt stress. Therefore, EIN3-SOS2 might link the ethylene signaling pathway and the SOS pathway in Arabidopsis salt responses. PMID:28300216

  20. Strong influence of medium pH condition on gas-phase biofilter ammonia removal, nitrous oxide generation and microbial communities.

    PubMed

    Yang, Liangcheng; Wang, Xinlei; Funk, Ted L

    2014-01-01

    Effects of pH on gas-phase biofilter performance including NH3 removal efficiency (RE), N2O generation, and microbial communities of ammonia oxidizers and denitrifies, are examined. A two-step experiment was carried out on four biofilters for 130 days. In step 1 with pH 8.0, NH3 REs were 85-95% and N2O concentrations were 0.1-0.4 ppm. In step 2, pH was adjusted to 4.5, 6.0, 8.0, and 9.5 in four biofilters, respectively. The acidified biofilters showed higher NH3 REs than the alkalized biofilters. N2O concentration in biofilters with pH 4.5 and 6.0 was increased to 1.5 and 0.5 ppm, respectively, while no change in the alkalized biofilters. Comparing to communities in step 1, the amoA and nosZ structures were altered when pH was changed to 4.5 and 6.0, but not at 9.5. Abundance of amoA was reduced at pH 4.5, while nosZ abundance was increased with considerably less changes in acidified biofilters compared to alkalized biofilters.

  1. Eine FPAA-Architektur zur rekonfigurierbaren Instantiierung von zeitkontinuierlichen Analogfiltern

    NASA Astrophysics Data System (ADS)

    Becker, J.; Manoli, Y.

    2005-05-01

    Im Folgenden wird eine neue Methodik von FPAAs (Field Programmable Analog Arrays) gezeigt, die speziell für die Instantiierung von zeitkontinuierlichen (continuous-time, CT) Analogfiltern in Hardware entwickelt wurde. Die Chiptopologie beinhaltet 17 digital konfigurierbare analoge Blöcke (configurable analog blocks, CABs), die durch ein hexagonales Netzwerk miteinander verbunden sind. Jeder CAB ist aus einstellbaren Gm-C Integratoren aufgebaut, welche das analoge Signal sowohl formen und seinen Weg durch die Matrix festlegen, gleichzeitig aber auch die Grundbausteine für zeitkontinuierliche Hochfrequenzfilter darstellen. Intelligente Pufferspeicher für die Ein-/Ausgänge (IO-buffer) garantieren die Rekonfigurierung der Matrix mit minimaler Störung des kontinuierlichen Analogsignals. Die Architektur wird als Hardwareplattform für beliebige Schaltungen, welche aus einer gegebenen Anzahl an Gm-C-Zellen bestehen, eingeführt und verifiziert bevor eine exemplarische Instantiierung eines Butterworth Filters 4. Ordnung in Biquad Anordnung gezeigt wird.

  2. A hybridized membrane-botanical biofilter for improving air quality in occupied spaces

    NASA Astrophysics Data System (ADS)

    Llewellyn, David; Darlington, Alan; van Ras, Niels; Kraakman, Bart; Dixon, Mike

    Botanical biofilters have been shown to be effective in improving indoor air quality through the removal of complex mixtures of gaseous contaminants typically found in human-occupied environments. Traditional, botanical biofilters have been comprised of plants rooted into a thin and highly porous synthetic medium that is hung on vertical surfaces. Water flows from the top of the biofilter and air is drawn horizontally through the rooting medium. These botanical biofilters have been successfully marketed in office and institutional settings. They operate efficiently, with adequate contaminant removal and little maintenance for many years. Depending on climate and outdoor air quality, botanical biofiltration can substantially reduce costs associated with ventilation of stale indoor air. However, there are several limitations that continue to inhibit widespread acceptance: 1. Current designs are architecturally limiting and inefficient at capturing ambient light 2. These biofilters can add significant amounts of humidity to an indoor space. This water loss also leads to a rapid accumulation of dissolved salts; reducing biofilter health and performance 3. There is the perception of potentially actively introducing harmful bioaerosols into the air stream 4. Design and practical limitations inhibit the entrance of this technology into the lucrative residential marketplace This paper describes the hybridization of membrane and botanical biofiltration technologies by incorporating a membrane array into the rootzone of a conventional interior planting. This technology has the potential for addressing all of the above limitations, expanding the range of indoor settings where botanical biofiltration can be applied. This technology was developed as the CSA-funded Canadian component an ESA-MAP project entitled: "Biological airfilter for air quality control of life support systems in manned space craft and other closed environments", A0-99-LSS-019. While the project addressed a

  3. Genomic analyses with biofilter 2.0: knowledge driven filtering, annotation, and model development

    PubMed Central

    2013-01-01

    Background The ever-growing wealth of biological information available through multiple comprehensive database repositories can be leveraged for advanced analysis of data. We have now extensively revised and updated the multi-purpose software tool Biofilter that allows researchers to annotate and/or filter data as well as generate gene-gene interaction models based on existing biological knowledge. Biofilter now has the Library of Knowledge Integration (LOKI), for accessing and integrating existing comprehensive database information, including more flexibility for how ambiguity of gene identifiers are handled. We have also updated the way importance scores for interaction models are generated. In addition, Biofilter 2.0 now works with a range of types and formats of data, including single nucleotide polymorphism (SNP) identifiers, rare variant identifiers, base pair positions, gene symbols, genetic regions, and copy number variant (CNV) location information. Results Biofilter provides a convenient single interface for accessing multiple publicly available human genetic data sources that have been compiled in the supporting database of LOKI. Information within LOKI includes genomic locations of SNPs and genes, as well as known relationships among genes and proteins such as interaction pairs, pathways and ontological categories. Via Biofilter 2.0 researchers can: • Annotate genomic location or region based data, such as results from association studies, or CNV analyses, with relevant biological knowledge for deeper interpretation • Filter genomic location or region based data on biological criteria, such as filtering a series SNPs to retain only SNPs present in specific genes within specific pathways of interest • Generate Predictive Models for gene-gene, SNP-SNP, or CNV-CNV interactions based on biological information, with priority for models to be tested based on biological relevance, thus narrowing the search space and reducing multiple hypothesis

  4. Exploring the potential of fungi for methane abatement: Performance evaluation of a fungal-bacterial biofilter.

    PubMed

    Lebrero, Raquel; López, Juan Carlos; Lehtinen, Iiro; Pérez, Rebeca; Quijano, Guillermo; Muñoz, Raúl

    2016-02-01

    Despite several fungal strains have been retrieved from methane-containing environments, the actual capacity and role of fungi on methane abatement is still unclear. The batch biodegradation tests here performed demonstrated the capacity of Graphium sp. to co-metabolically biodegrade methane and methanol. Moreover, the performance and microbiology of a fungal-bacterial compost biofilter treating methane at concentrations of ∼2% was evaluated at empty bed residence times of 40 and 20 min under different irrigation rates. The daily addition of 200 mL of mineral medium resulted in elimination capacities of 36.6 ± 0.7 g m(-3) h(-1) and removal efficiencies of ≈90% at the lowest residence time. The indigenous fungal community of the compost was predominant in the final microbial population and outcompeted the inoculated Graphium sp. during biofilter operation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. A biofilter for treating toluene vapors: performance evaluation and microbial counts behavior.

    PubMed

    Zhu, Yazhong; Li, Shunyi; Luo, Yimeng; Ma, Hongye; Wang, Yan

    2016-01-01

    A lab-scale biofilter packed with mixed packing materials was used for degradation of toluene. Different empty bed residence times, 148.3, 74.2 and 49.4 s, were tested for inlet concentration ranging from 0.2 to 1.2 g/m(3). The maximum elimination capacity of 36.0 g/(m(3) h) occurred at an inlet loading rate of 45.9 g/(m(3) h). The contribution of the lower layer was higher than other layers and always had the highest elimination capacity. The carbon dioxide production rate and distribution of micro-organisms followed toluene elimination capacities. The results of this study indicated that mixed packing materials could be considered as a potential biofilter carrier, with low pressure drop (less than 84.9 Pa/m), for treating air streams containing VOCs.

  6. A biofilter for treating toluene vapors: performance evaluation and microbial counts behavior

    PubMed Central

    Zhu, Yazhong; Luo, Yimeng; Ma, Hongye; Wang, Yan

    2016-01-01

    A lab-scale biofilter packed with mixed packing materials was used for degradation of toluene. Different empty bed residence times, 148.3, 74.2 and 49.4 s, were tested for inlet concentration ranging from 0.2 to 1.2 g/m3. The maximum elimination capacity of 36.0 g/(m3 h) occurred at an inlet loading rate of 45.9 g/(m3 h). The contribution of the lower layer was higher than other layers and always had the highest elimination capacity. The carbon dioxide production rate and distribution of micro-organisms followed toluene elimination capacities. The results of this study indicated that mixed packing materials could be considered as a potential biofilter carrier, with low pressure drop (less than 84.9 Pa/m), for treating air streams containing VOCs. PMID:27231662

  7. H2S gas biological removal efficiency and bacterial community diversity in biofilter treating wastewater odor.

    PubMed

    Omri, Ilhem; Bouallagui, Hassib; Aouidi, Fathia; Godon, Jean-Jacques; Hamdi, Moktar

    2011-11-01

    The objective of this study was to assess the feasibility of using a biofilter system to treat hydrogen sulfide (H2S) contaminated air and to characterize its microbial community. The biofilter system was packed with peat. During the experimental work, the peat was divided in three layers (down, middle, and up). Satisfactory removal efficiencies of H2S were proved and reached 99% for the majority of the run time at an empty bed retention time (EBRT) of 60 s. The polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method was used to uncover the changes in the microbial community between the different layers. Analysis of SSCP profiles demonstrated significant differences in community structure from a layer to another with a strong decrease in species diversity towards the up layer. It was found that the used support was suitable for microorganism growth, and may have a potential application in H2S biofiltration system.

  8. Optimization of the treatment of carbon monoxide-polluted air in biofilters.

    PubMed

    Jin, Yaomin; Guo, Ling; Veiga, María C; Kennes, Christian

    2009-01-01

    This work is the first extensive study on the removal of carbon monoxide from polluted air in biofilters. It compares the performance of two packing materials, namely lava rock alone and a mixture of peat and lava rock. The results show that the biofilter packed with the mixture of peat and lava rock performed much better than the other one. The effect of operating conditions as, among others, the inlet concentration and the empty bed residence time (EBRT) were studied. A maximum elimination capacity of 33 g m(-3) h(-1) was obtained with the mixed packing with more than 85% removal efficiency at EBRT of 3 min or more. Somewhat lower performances were reached at shorter EBRT. The results presented here suggest that the mixture of lava rock and peat, subject to further optimization, offers potential for the biological removal of CO from polluted gas streams.

  9. Nagelbefall kann bei Patienten mit Psoriasis auf eine Enthesiopathie hinweisen.

    PubMed

    Castellanos-González, Maria; Joven, Beatriz Esther; Sánchez, Julio; Andrés-Esteban, Eva María; Vanaclocha-Sebastián, Francisco; Romero, Pablo Ortiz; Díaz, Raquel Rivera

    2016-11-01

    Obwohl subklinische Enthesiopathie ein gut etabliertes diagnostisches Merkmal der Psoriasisarthritis (PsA) ist, wird sie häufig übersehen, da viele Patienten asymptomatisch sind. Gäbe es klinische Hinweise auf das Vorliegen einer Enthesiopathie, würde dies den Klinikern die Möglichkeit eröffnen, eine PsA frühzeitig zu diagnostizieren. Es wurde eine monozentrische prospektive Studie mit insgesamt 90 Psoriasis-Patienten durchgeführt, um mittels Ultraschall das Vorliegen von Enthesenanomalien zu untersuchen und eine Korrelation mit dem Befall der Nägel festzustellen. Enthesenanomalien wurden bei 23 Patienten (25,5 %) gefunden, von denen 19 (82,6 %) Nagelbefall aufwiesen. Bei 4 Patienten waren die Nägel nicht betroffen. Enthesiopathie lag bei 31,1 % (19/61) der Patienten mit Onychopathie vor, von den Patienten ohne Nagelbefall litten nur 13,8 % (4/29) an Enthesiopathie (p = 0,07). Zwischen dem Target-NAPSI-Score und dem Vorliegen einer Enthesiopathie bestand eine signifikante Korrelation. Eine signifikante Korrelation bestand darüber hinaus auch zwischen dem Vorliegen einer Enthesiopathie und der Anzahl der betroffenen Nägel (p = 0,035). Klinische Belege für eine Onychopathie können der Schlüssel für die frühe Diagnose einer Enthesiopathie bei Psoriasis-Patienten sein. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  10. Relevance and Diversity of Nitrospira Populations in Biofilters of Brackish RAS

    PubMed Central

    Kruse, Myriam; Keuter, Sabine; Bakker, Evert; Spieck, Eva; Eggers, Till; Lipski, André

    2013-01-01

    Lithoautotrophic nitrite-oxidizing bacterial populations from moving-bed biofilters of brackish recirculation aquaculture systems (RAS; shrimp and barramundi) were tested for their metabolic activity and phylogenetic diversity. Samples from the biofilters were labeled with 13C-bicarbonate and supplemented with nitrite at concentrations of 0.3, 3 and 10 mM, and incubated at 17 and 28°C, respectively. The biofilm material was analyzed by fatty acid methyl ester - stable isotope probing (FAME-SIP). High portions of up to 45% of Nitrospira-related labeled lipid markers were found confirming that Nitrospira is the major autotrophic nitrite oxidizer in these brackish systems with high nitrogen loads. Other nitrite-oxidizing bacteria such as Nitrobacter or Nitrotoga were functionally not relevant in the investigated biofilters. Nitrospira-related 16S rRNA gene sequences were obtained from the samples with 10 mM nitrite and analyzed by a cloning approach. Sequence studies revealed four different phylogenetic clusters within the marine sublineage IV of Nitrospira, though most sequences clustered with the type strain of Nitrospira marina and with a strain isolated from a marine RAS. Three lipids dominated the whole fatty acid profiles of nitrite-oxidizing marine and brackish enrichments of Nitrospira sublineage IV organisms. The membranes included two marker lipids (16∶1 cis7 and 16∶1 cis11) combined with the non-specific acid 16∶0 as major compounds and confirmed these marker lipids as characteristic for sublineage IV species. The predominant labeling of these characteristic fatty acids and the phylogenetic sequence analyses of the marine Nitrospira sublineage IV identified organisms of this sublineage as main autotrophic nitrite-oxidizers in the investigated brackish biofilter systems. PMID:23705006

  11. A comparative study of physical and chemical processes for removal of biomass in biofilters.

    PubMed

    Flores-Valle, Sergio Odín; Ríos-Bernÿ, Omar; Chanona-Pérez, Jorge; Fregoso-Aguilar, Tomas; Morales-González, José A; Prado-Rubianes, Oscar Jesús; Herrera-Bucio, Rafael; López-Albarán, Pablo; Morales-González, Ángel; Garibay-Febles, Vicente; Domínguez, Enrique Godínez; Kennes, Christian; Veiga-Barbazán, Ma Carmen; Mendoza-Pérez, Jorge Alberto

    2011-08-15

    After 6 months of operation a long-term biofilter was stopped for two weeks and then it was started up again for a second experimental period of almost 1.3 years, with high toluene loads and submitted to several physical and chemical treatments in order to remove excess biomass that could affect the reactor's performance due to clogging, whose main effect is a high pressure drop. Elimination capacity and removal efficiency were determined after each treatment. The methods applied were: filling with water and draining, backwashing, and air sparging. Different flows and temperatures (20, 30, 45 and 60 °C) were applied, either with distilled water or with different chemicals in aqueous solutions. Treatments with chemicals caused a decrease of the biofilter performance, requiring periods of 1 to 2 weeks to recover previous values. The results indicate that air sparging with pure distilled water as well as with solutions of NaOH (0.01% w/v) and NaOCl (0.01% w/v) were the treatments that removed more biomass, working either at 20, 30 or 45 °C and at relatively low flow rates (below 320 L h(-1)), but with a high biodegradation inhibition after the treatments. Dry biomass (g VS) content was determined at three different heights of the biofilter in order to carry out each experiment under the same conditions. The same amount of dry biomass when applying a treatment was established so it could be considered that the biofilm conditions were identical. Wet biomass was used as a control of the biofilter's water content during treatments. Several batch assays were performed to support and quantify the observed inhibitory effects of the different chemicals and temperatures applied.

  12. Community Analysis and Recovery of Phenol-degrading Bacteria from Drinking Water Biofilters.

    PubMed

    Gu, Qihui; Wu, Qingping; Zhang, Jumei; Guo, Weipeng; Wu, Huiqing; Sun, Ming

    2016-01-01

    Phenol is a ubiquitous organic contaminant in drinking water. Biodegradation plays an important role in the elimination of phenol pollution in the environment, but the information about phenol removal by drinking water biofilters is still lacking. Herein, we study an acclimated bacterial community that can degrade over 80% of 300 mg/L phenol within 3 days. PCR detection of genotypes involved in bacterial phenol degradation revealed that the degradation pathways contained the initial oxidative attack by phenol hydroxylase, and subsequent ring fission by catechol 1,2-dioxygenase. Based on the PCR denatured gradient gel electrophoresis (PCR-DGGE) profiles of bacteria from biological activated carbon (BAC), the predominant bacteria in drinking water biofilters including Delftia sp., Achromobacter sp., and Agrobacterium sp., which together comprised up to 50% of the total microorganisms. In addition, a shift in bacterial community structure was observed during phenol biodegradation. Furthermore, the most effective phenol-degrading strain DW-1 that correspond to the main band in denaturing gradient gel electrophoresis (DGGE) profile was isolated and identified as Acinetobacter sp., according to phylogenetic analyses of the 16S ribosomal ribonucleic acid (rRNA) gene sequences. The strain DW-1 also produced the most important enzyme, phenol hydroxylase, and it also exhibited a good ability to degrade phenol when immobilized on granular active carbon (GAC). This study indicates that the enrichment culture has great potential application for treatment of phenol-polluted drinking water sources, and the indigenous phenol-degrading microorganism could recover from drinking water biofilters as an efficient resource for phenol removal. Therefore, the aim of this study is to draw attention to recover native phenol-degrading bacteria from drinking water biofilters, and use these native microorganisms as phenolic water remediation in drinking water sources.

  13. Community Analysis and Recovery of Phenol-degrading Bacteria from Drinking Water Biofilters

    PubMed Central

    Gu, Qihui; Wu, Qingping; Zhang, Jumei; Guo, Weipeng; Wu, Huiqing; Sun, Ming

    2016-01-01

    Phenol is a ubiquitous organic contaminant in drinking water. Biodegradation plays an important role in the elimination of phenol pollution in the environment, but the information about phenol removal by drinking water biofilters is still lacking. Herein, we study an acclimated bacterial community that can degrade over 80% of 300 mg/L phenol within 3 days. PCR detection of genotypes involved in bacterial phenol degradation revealed that the degradation pathways contained the initial oxidative attack by phenol hydroxylase, and subsequent ring fission by catechol 1,2-dioxygenase. Based on the PCR denatured gradient gel electrophoresis (PCR-DGGE) profiles of bacteria from biological activated carbon (BAC), the predominant bacteria in drinking water biofilters including Delftia sp., Achromobacter sp., and Agrobacterium sp., which together comprised up to 50% of the total microorganisms. In addition, a shift in bacterial community structure was observed during phenol biodegradation. Furthermore, the most effective phenol-degrading strain DW-1 that correspond to the main band in denaturing gradient gel electrophoresis (DGGE) profile was isolated and identified as Acinetobacter sp., according to phylogenetic analyses of the 16S ribosomal ribonucleic acid (rRNA) gene sequences. The strain DW-1 also produced the most important enzyme, phenol hydroxylase, and it also exhibited a good ability to degrade phenol when immobilized on granular active carbon (GAC). This study indicates that the enrichment culture has great potential application for treatment of phenol-polluted drinking water sources, and the indigenous phenol-degrading microorganism could recover from drinking water biofilters as an efficient resource for phenol removal. Therefore, the aim of this study is to draw attention to recover native phenol-degrading bacteria from drinking water biofilters, and use these native microorganisms as phenolic water remediation in drinking water sources. PMID:27148185

  14. Eine selbstkonsistente Carleman Linearisierung zur Analyse von Oszillatoren

    NASA Astrophysics Data System (ADS)

    Weber, Harry; Mathis, Wolfgang

    2017-09-01

    Die Analyse nichtlinearer dynamischer Schaltungen ist bis heute eine herausfordernde Aufgabe, da nur selten analytische Lösungen angegeben werden können. Daher wurden eine Vielzahl von Methoden entwickelt, um eine qualitative oder quantitative Näherung für die Lösungen der Netzwerkgleichung zu erhalten. Oftmals wird beispielsweise eine Kleinsignalanalyse mit Hilfe einer Taylorreihe in einem Arbeitspunkt durchgeführt, die nach den Gliedern erster Ordnung abgebrochen wird. Allerdings ist diese Linearisierung nur in der Nähe des stabilen Arbeitspunktes für hyperbolische Systeme gültig. Besonders für die Analyse des dynamischen Verhaltens von Oszillatoren treten jedoch nicht-hyperbolische Systeme auf, sodass diese Methode nicht angewendet werden kann Mathis(2000). Carleman hat gezeigt, dass nichtlineare Differentialgleichungen mit polynomiellen Nichtlinearitäten in ein unendliches System von linearen Differentialgleichungen transformiert werden können Carleman(1932). Wird das unendlichdimensionale Gleichungssystem für numerische Zwecke abgebrochen, kann bei Oszillatoren der Übergang in eine stationäre Schwingung (Grenzzyklus) nicht wiedergegeben werden.

    In diesem Beitrag wird eine selbstkonsistente Carleman Linearisierung zur Untersuchung von Oszillatoren vorgestellt, die auch dann anwendbar ist, wenn die Nichtlinearitäten keinen Polynomen entsprechen. Anstelle einer linearen Näherung um einen Arbeitspunkt, erfolgt mit Hilfe der Carleman Linearisierung eine Approximation auf einem vorgegebenen Gebiet. Da es jedoch mit der selbstkonsistenten Technik nicht möglich ist, das stationäre Verhalten von Oszillatoren zu beschreiben, wird die Berechnung einer Poincaré-Abbildung durchgeführt. Mit dieser ist eine anschließende Analyse des Oszillators möglich.

  15. Biotreatment of ammonia in air by an immobilized Nitrosomonas europaea biofilter

    SciTech Connect

    Chung, Y.C.; Huang, C.

    1998-09-01

    The chemoautotrophic microorganism Nitrosomonas europaea has been utilized to remove gaseous ammonia in a continuous reactor. Extensive tests including removal characteristics, metabolic products, and removal efficiencies of ammonia by N. europaea were conducted. The operational principles governing the biofilter and the question of the heterotroph contamination were also studied. The optimum pH value and operating temperature required to effectively remove ammonia were found to be pH 7.5 and 30 C, respectively. When the diluted inlet ammonia concentration was 10 or 20 ppm, the biofilter achieved a 99% removal efficiency after 4 days of operation. However, higher ammonia inlet concentrations and heterotroph contamination resulted in a lower removal efficiency. The results showed that the maximum removal rate and apparent saturation constant were 1.11 g-N/day/kg-bead and 63.67 ppm, respectively. The mainly metabolic product of ammonia oxidation was determined to be nitrite, but the conversion ratio was dependent on whether the contaminations by heterotrophic bacteria were present. From an operating perspective, if the ammonia emission limit (i.e., 1 ppm) was to be achieved, the maximum inlet concentration could not exceed 75 ppm. These results suggest that the immobilized Nitrosomonas europaea biofilter provides a significant potential for treating ammonia in the gaseous phase.

  16. Operational performance, biomass and microbial community structure: impacts of backwashing on drinking water biofilter.

    PubMed

    Liao, Xiaobin; Chen, Chao; Zhang, Jingxu; Dai, Yu; Zhang, Xiaojian; Xie, Shuguang

    2015-01-01

    Biofiltration has been widely used to reduce organic matter and control the formation of disinfection by-products in drinking water. Backwashing might affect the biofilters' performance and the attached microbiota on filter medium. In this study, the impacts of backwashing on the removal of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and N-nitrosamine precursors by a pilot-scale biological activated carbon (BAC) filtration system were investigated. The impacts of backwashing on biomass and microbial community structure of BAC biofilm were also investigated. Phospholipid fatty acid (PLFA) analysis showed that backwashing reduced nearly half of the attached biomass on granular activated carbon (GAC) particles, followed by a recovery to the pre-backwashing biomass concentration in 2 days after backwashing. Backwashing was found to transitionally improve the removal of DOC, DON and N-nitrosamine precursors. MiSeq sequencing analysis revealed that backwashing had a strong impact on the bacterial diversity and community structure of BAC biofilm, but they could gradually recover with the operating time after backwashing. Phylum Proteobacteria was the largest bacterial group in BAC biofilm. Microorganisms from genera Bradyrhizobium, Hyphomicrobium, Microcystis and Sphingobium might contribute to the effective removal of nitrogenous organic compounds by drinking water biofilter. This work could add some new insights towards the operation of drinking water biofilters and the biological removal of organic matter.

  17. Two-step pilot-scale biofilter system for the abatement of food waste composting emission.

    PubMed

    Galera, Melvin Maaliw; Cho, Eulsaeng; Kim, Yekyung; Farnazo, Danvir; Park, Shin-Jung; Oh, Young-Sook; Park, Jae Kyu; Chung, Wook-Jin

    2008-03-01

    A pilot-scale two-step biofilter system was evaluated in treating food waste composting emission for 220 days. Wood chips were packed at the bottom section while mixture of rock wool and earthworm compost (6% w/v) was packed at the top section. Inlet ammonia concentration was found to be dominant and intermittent. The overall ammonia removal of over 98% was achieved, 70% of which was removed in the wood chip section. The highest ammonia elimination capacity was determined to be 39.43 g-NH(3)/m(3)/h at 99.5% removal efficiency. From biodegradation kinetic analysis, the maximum removal rate, V(m), of the wood chip section was determined to be 200 g-NH(3)/m(3)/h and the saturation constant, K(s), 180 mg/m(3). For the rock wool-earthworm cast mixture section, the V(m) was 87 g-NH(3)/m(3)/h and K(s) was 87 mg/m(3). Complete removal of hydrogen sulfide and most trace compounds were achieved by the biofilter. Highest hydrogen sulfide elimination rate was 0.22 g-H(2)S/m(3)/h. The biofilter was optimized from 24 to 16 s EBRT with resulting low average pressure drops of 16 and 29 mm H(2)O/m, respectively.

  18. H2S and VOCs abatement robustness in biofilters and air diffusion bioreactors: A comparative study.

    PubMed

    Lebrero, Raquel; Rodríguez, Elisa; Martin, María; García-Encina, Pedro A; Muñoz, Raúl

    2010-07-01

    The robustness of a conventional biofilter and an air diffusion bioreactor (ADB) was comparatively evaluated in laboratory-scale plants treating a mixture of H2S, butanone, toluene and alpha-pinene at gas residence times of 50 s. Under steady state conditions, H2S, butanone and toluene were almost completely degraded, while alpha-pinene removal did not exhibit removal efficiencies (REs) higher than 11.0 +/- 2.3%. Fluctuations in temperature from 8 degrees C to 30 degrees C did not impact significantly process performance in any of the biotechnologies tested. However, while the ADB unit was able to cope with three and six fold step increases in pollutant loadings, volatile organic compounds (VOCs) REs noticeably decreased in the biofilter when subjected to a six fold step change (i.e. 90% reduction for butanone and 30% for toluene). A process shutdown of five days resulted in the temporary loss of butanone and toluene RE in the ADB system. A lack of irrigation during five days caused a slight decrease in the biofilter REs, while a failure in the pH control system drastically affected the ADB performance. Finally, process robustness was quantified. The calculated overall risks showed that both biotechnologies were reliable for H2S and VOCs treatment in wastewater treatment plants, ADB diffusion exhibiting a higher robustness towards fluctuations commonly found under routine operation. This robustness was further confirmed by the high stability of the DGGE profiles.

  19. Measurement of biosolids compost odor emissions from a windrow, static pile, and biofilter.

    PubMed

    Rosenfeld, Paul; Grey, Mark; Sellew, Paul

    2004-01-01

    A pilot study was conducted to compare odor emissions from a windrow process and an aerated static pile and to determine the odor reduction efficiency of a pilot two-phase biofilter for odor control of biosolids composting. Chemical compounds identified as responsible for odors from biosolids composting include ammonia, dimethyl disulfide, carbon disulfide, formic acid, acetic acid, and sulfur dioxide (or carbonyl sulfide). Aeration was found to reduce the concentration of ammonia, formic acid, and acetic acid by 72, 57, and 11%, respectively, compared with a nearby windrow, while dimethyl sulfide, carbon disulfide, and sulfur dioxide (or carbonyl sulfide) concentrations were below detection limits. Using dilution-to-threshold olfactometry, aeration followed by biofiltration was found to reduce the odor from biosolids composting by 98%. Biofiltration also altered the character of odor emissions from biosolids composting, producing a less offensive odor with an earthy character. Biofiltration was found to reduce the concentration of ammonia, dimethyl disulfide, carbon disulfide, formic acid, acetic acid, and sulfur dioxide (or carbonyl sulfide) by 99, 90, 32, 100, 34, and 100%, respectively. The concentrations of those odorants were estimated to be 3700, 110000, 26,37,5, and 1.2 times reported human detection limits before the two-phase biofilter, respectively, and 42,9600,18,0,3, and 0 times human detection limits after the biofilter, respectively.

  20. E. coli removal in laboratory scale stormwater biofilters: Influence of vegetation and submerged zone

    NASA Astrophysics Data System (ADS)

    Chandrasena, G. I.; Pham, T.; Payne, E. G.; Deletic, A.; McCarthy, D. T.

    2014-11-01

    Biofilters, also known as bioretention areas or raingardens, are an effective treatment option for the removal of various pollutants from stormwater. However, they show variable treatment efficiency for the removal of indicator bacteria, and the operational and design factors which impact this variability are largely unknown. This study uses a laboratory scale column set-up to explore how Escherichia coli (the chosen indicator organism) removal in the stormwater biofilters is impacted by: plant presence and species type, the presence of a submerged zone (SZ), and operational conditions (duration of dry periods and changes over the initial stages of the system's life-span). Vegetation selection was found to be important for E. coli removal and the highly performing plant species were associated with lower infiltration rates. Based on the current results, a biofilter planted with Leptospermum continentale, Melaleuca incana or Palmetto buffalo and comprising a SZ can be recommended for improved E. coli removal. Inclusion of SZ was found to generally enhance the removal performance; which may be explained by the contribution of microbial processes that are happening within the SZ (such as predation/competition and natural die-off). Results also suggest that the E. coli removal performance is reduced after a significant dry period, while the overall removal performance improves over time as systems mature.

  1. Assessment of Changes in Microbial Community Structure during Operation of an Ammonia Biofilter with Molecular Tools

    PubMed Central

    Sakano, Y.; Kerkhof, L.

    1998-01-01

    Biofiltration has been used for two decades to remove odors and various volatile organic and inorganic compounds in contaminated off-gas streams. Although biofiltration is widely practiced, there have been few studies of the bacteria responsible for the removal of air contaminants in biofilters. In this study, molecular techniques were used to identify bacteria in a laboratory-scale ammonia biofilter. Both 16S rRNA and ammonia monooxygenase (amoA) genes were used to characterize the heterotrophic and ammonia-oxidizing bacteria collected from the biofilter during a 102-day experiment. The overall diversity of the heterotrophic microbial population appeared to decrease by 38% at the end of the experiment. The community structure of the heterotrophic population also shifted from predominantly members of two subdivisions of the Proteobacteria (the beta and gamma subdivisions) to members of one subdivision (the gamma subdivision). An overall decrease in the diversity of ammonia monooxygenase genes was not observed. However, a shift from groups dominated by organisms containing Nitrosomonas-like and Nitrosospira-like amoA genes to groups dominated by organisms containing only Nitrosospira-like amoA genes was observed. In addition, a new amoA gene was discovered. This new gene is the first freshwater amoA gene that is closely affiliated with Nitrosococcus oceanus and the particulate methane monooxygenase gene from the methane oxidizers belonging to the gamma subdivision of the Proteobacteria. PMID:9835577

  2. Research into acetone removal from air by biofiltration using a biofilter with straight structure plates.

    PubMed

    Baltrėnas, Pranas; Zagorskis, Alvydas; Misevičius, Antonas

    2015-03-04

    The biological air treatment method is based on the biological destruction of organic compounds using certain cultures of microorganisms. This method is simple and may be applied in many branches of industry. The main element of biological air treatment devices is a filter charge. Tests were carried out using a new-generation laboratory air purifier with a plate structure. This purifier is called biofilter. The biofilter has a special system for packing material humidification which does not require additional energy inputs. In order to extend the packing material's durability, it was composed of thermally treated birch fibre. Pollutant (acetone) biodegradation occurred on thermally treated wood fibre in this research. According to the performed tests and the received results, the process of biodestruction was highly efficient. When acetone was passed through biofilter's packing material at 0.08 m s(-1) rate, the efficiency of the biofiltration process was from 70% up to 90%. The species of bacteria capable of removing acetone vapour from the air, i.e. Bacillus (B. cereus, B. subtilis), Pseudomonas (P. aeruginosa, P. putida), Stapylococcus (S. aureus) and Rhodococcus sp., was identified in this study during the process of biofiltration. Their amount in the biological packing material changed from 1.6 × 10(7) to 3.7 × 10(11) CFU g(-1).

  3. Performance study of biofilter developed to treat H2S from wastewater odour.

    PubMed

    Omri, Ilhem; Aouidi, Fethia; Bouallagui, Hassib; Godon, Jean-Jacques; Hamdi, Moktar

    2013-04-01

    Biofiltration is an efficient biotechnological process used for waste gas abatement in various industrial processes. It offers low operating and capital costs and produces minimal secondary waste streams. The objective of this study was to evaluate the performance of a pilot scale biofilter in terms of pollutants' removal efficiencies and the bacterial dynamics under different inlet concentrations of H2S. The treatment of odourous pollutants by biofiltration was investigated at a municipal wastewater treatment plant (WWTP) (Charguia, Tunis, Tunisia). Sampling and analyses were conducted for 150 days. Inlet H2S concentration recorded was between 200 and 1300 mg H2S.m(-3). Removal efficiencies reached 99% for the majority of the running time at an empty bed retention time (EBRT) of 60 s. Heterotrophic bacteria were found to be the dominant microorganisms in the biofilter. The bacteria were identified as the members of the genus Bacillus, Pseudomonas and xanthomonadacea bacterium. The polymerase chain reaction-single stranded conformation polymorphism (PCR-SSCP) method showed that bacterial community profiles changed with the H2S inlet concentration. Our results indicated that the biofilter system, containing peat as the packing material, was proved able to remove H2S from the WWTP odourous pollutants.

  4. Performance study of biofilter developed to treat H2S from wastewater odour

    PubMed Central

    Omri, Ilhem; Aouidi, Fethia; Bouallagui, Hassib; Godon, Jean-Jacques; Hamdi, Moktar

    2013-01-01

    Biofiltration is an efficient biotechnological process used for waste gas abatement in various industrial processes. It offers low operating and capital costs and produces minimal secondary waste streams. The objective of this study was to evaluate the performance of a pilot scale biofilter in terms of pollutants’ removal efficiencies and the bacterial dynamics under different inlet concentrations of H2S. The treatment of odourous pollutants by biofiltration was investigated at a municipal wastewater treatment plant (WWTP) (Charguia, Tunis, Tunisia). Sampling and analyses were conducted for 150 days. Inlet H2S concentration recorded was between 200 and 1300 mg H2S.m−3. Removal efficiencies reached 99% for the majority of the running time at an empty bed retention time (EBRT) of 60 s. Heterotrophic bacteria were found to be the dominant microorganisms in the biofilter. The bacteria were identified as the members of the genus Bacillus, Pseudomonas and xanthomonadacea bacterium. The polymerase chain reaction-single stranded conformation polymorphism (PCR-SSCP) method showed that bacterial community profiles changed with the H2S inlet concentration. Our results indicated that the biofilter system, containing peat as the packing material, was proved able to remove H2S from the WWTP odourous pollutants. PMID:23961233

  5. Functional rigidity of a methane biofilter during the temporal microbial succession.

    PubMed

    Kim, Tae Gwan; Jeong, So-Yeon; Cho, Kyung-Suk

    2014-04-01

    Temporal microbial succession was investigated in relation to the performance of a methane biofilter. A laboratory-scale biofilter packed with perlite was operated for 108 days, without a deliberate biomass control. The system performance was stable over the period with a mean elimination capacity of 1,563 g m(-3) day(-1), despite a temporal deterioration (45-56 days). Ribosomal-tag pyrosequencing showed that bacterial communities at days 14-28 were distinct from those of days 68-108. The accumulation of nonviable substances strongly coincided with the community change (R (2) > 0.97). Rhodobacter, Hydrogenophaga, and Methylomonas were dominated in the earlier period, while Methylocaldum and Methylococcus were abundant in the later period. The methanotrophic proportion gradually increased to 41 %, and type I methanotrophs became predominant over time. However, community structure and methanotrophic population density stably retained over time, allowing the system to keep the similar performance. Therefore, the perlite biofilter system was functionally rigid against the temporal microbial succession.

  6. Predictive Power of Clean Bed Filtration Theory for Fecal Indicator Bacteria Removal in Stormwater Biofilters.

    PubMed

    Parker, Emily A; Rippy, Megan A; Mehring, Andrew S; Winfrey, Brandon K; Ambrose, Richard F; Levin, Lisa A; Grant, Stanley B

    2017-05-16

    Green infrastructure (also referred to as low impact development, or LID) has the potential to transform urban stormwater runoff from an environmental threat to a valuable water resource. In this paper we focus on the removal of fecal indicator bacteria (FIB, a pollutant responsible for runoff-associated inland and coastal beach closures) in stormwater biofilters (a common type of green infrastructure). Drawing on a combination of previously published and new laboratory studies of FIB removal in biofilters, we find that 66% of the variance in FIB removal rates can be explained by clean bed filtration theory (CBFT, 31%), antecedent dry period (14%), study effect (8%), biofilter age (7%), and the presence or absence of shrubs (6%). Our analysis suggests that, with the exception of shrubs, plants affect FIB removal indirectly by changing the infiltration rate, not directly by changing the FIB removal mechanisms or altering filtration rates in ways not already accounted for by CBFT. The analysis presented here represents a significant step forward in our understanding of how physicochemical theories (such as CBFT) can be melded with hydrology, engineering design, and ecology to improve the water quality benefits of green infrastructure.

  7. Research into acetone removal from air by biofiltration using a biofilter with straight structure plates

    PubMed Central

    Baltrėnas, Pranas; Zagorskis, Alvydas; Misevičius, Antonas

    2015-01-01

    The biological air treatment method is based on the biological destruction of organic compounds using certain cultures of microorganisms. This method is simple and may be applied in many branches of industry. The main element of biological air treatment devices is a filter charge. Tests were carried out using a new-generation laboratory air purifier with a plate structure. This purifier is called biofilter. The biofilter has a special system for packing material humidification which does not require additional energy inputs. In order to extend the packing material's durability, it was composed of thermally treated birch fibre. Pollutant (acetone) biodegradation occurred on thermally treated wood fibre in this research. According to the performed tests and the received results, the process of biodestruction was highly efficient. When acetone was passed through biofilter's packing material at 0.08 m s−1 rate, the efficiency of the biofiltration process was from 70% up to 90%. The species of bacteria capable of removing acetone vapour from the air, i.e. Bacillus (B. cereus, B. subtilis), Pseudomonas (P. aeruginosa, P. putida), Stapylococcus (S. aureus) and Rhodococcus sp., was identified in this study during the process of biofiltration. Their amount in the biological packing material changed from 1.6 × 107 to 3.7 × 1011 CFU g−1. PMID:26019659

  8. Analytical model of dual-media biofilter for removal of organic air pollutants

    SciTech Connect

    Abumaizar, R.J.; Smith, E.H.; Kocher, W.

    1997-06-01

    A steady-state mathematical model is presented to describe the kinetics of volatile organic compound (VOC) removal in biofilters that consist of a mixed compost and granular activated carbon (GAC) medium. The model describes the basic transport of VOCs from the gas phase into the liquid phase of the compost biofilm and into the carbon particles, using the assumptions of diffusion as characterized by Fick`s law. The kinetics of biological degradation of substrate (pollutant) in the compost biofilm are assumed to follow a Monod-like relationship. Experimental data were compared with model predictions under steady-state conditions for treatment of a mixture of benzene, toluene, ethylbenzene, and o-xylene (BTEX) vapors. Best results were obtained when model applications were divided according to first-order biodegradation kinetics for relatively low influent concentrations (< 50 ppm) of pollutants and zero-order reaction for higher (235--440 ppm) influent concentrations. In both instances, the model produced suitable approximation of experimental bed depth versus concentration profiles at steady state for individual compounds in biofilters containing small but varying amounts of GAC. The presence of GAC improved BTEX removal efficiencies over a biofilter containing only compost.

  9. Methanol removal efficiency and bacterial diversity of an activated carbon biofilter.

    PubMed

    Babbitt, Callie W; Pacheco, Adriana; Lindner, Angela S

    2009-12-01

    Motivated by the need to establish an economical and environmentally friendly methanol control technology for the pulp and paper industry, a bench-scale activated carbon biofiltration system was developed. This system was evaluated for its performance in removing methanol from an artificially contaminated air stream and characterized for its bacterial diversity over time, under varied methanol loading rates, and in different spatial regions of the filter. The biofilter system, composed of a novel packing mixture, provided an excellent support for growth and activity of methanol-degrading bacteria, resulting in approximately 100% methanol removal efficiency for loading rates of 1-17 g/m(3) packing/h, when operated both with and without inoculum containing enriched methanol-degrading bacteria. Although bacterial diversity and abundance varied over the length of the biofilter, the populations present rapidly formed a stable community that was maintained over the entire 138-day operation of the system and through variable operating conditions, as observed by PCR-DGGE methods that targeted all bacteria as well as specific methanol-oxidizing microorganisms. Phylogenetic analysis of bands excised and sequenced from DGGE gels indicated that the biofilter system supported a diverse community of methanol-degrading bacteria, with high similarity to species in the genera Methylophilus (beta-proteobacteria), Hyphomicrobium and Methylocella (both alpha-proteobacteria).

  10. Characterisation of the behaviour of particles in biofilters for pre-treatment of drinking water.

    PubMed

    Persson, Frank; Långmark, Jonas; Heinicke, Gerald; Hedberg, Torsten; Tobiason, John; Stenström, Thor-Axel; Hermansson, Malte

    2005-10-01

    Biofiltration of surface water was examined using granular activated carbon (GAC) and expanded clay (EC). Particle removal was 60-90%, measured by flow cytometry, which enabled discrimination between total- and autofluorescent particles (microalgae) in size ranges of 0.4-1 and 1-15 microm, and measured by on-line particle counting. Total particles were removed at a higher degree than autofluorescent particles. The biofilters were also challenged with 1 microm fluorescent microspheres with hydrophobic and hydrophilic surface characteristics and bacteriophages (Salmonella typhimurium 28B). Added microspheres were removed at 97-99% (hydrophobic) and 85-89% (hydrophilic) after 5 hydraulic residence times (HRT) and microspheres retained in the biofilter media were slowly detaching into the filtrate for a long time after the addition. Removal of bacteriophages (5 HRT) was considerably lower at 40-59%, and no long-lasting detachment was observed. A comparison of experimental data with theoretical predictions for removal of particles in clean granular media filters revealed a similar or higher removal of particles around 1 microm in size than predicted, while bacteriophages were removed at a similar or lesser extent than predicted. The results highlight the selectivity and dynamic behaviour of the particle removal processes and have implications for operation and microbial risk assessment of a treatment train with biofilters as pre-treatment.

  11. Assessment of changes in microbial community structure during operation of an ammonia biofilter with molecular tools

    NASA Technical Reports Server (NTRS)

    Sakano, Y.; Kerkhof, L.; Janes, H. W. (Principal Investigator)

    1998-01-01

    Biofiltration has been used for two decades to remove odors and various volatile organic and inorganic compounds in contaminated off-gas streams. Although biofiltration is widely practiced, there have been few studies of the bacteria responsible for the removal of air contaminants in biofilters. In this study, molecular techniques were used to identify bacteria in a laboratory-scale ammonia biofilter. Both 16S rRNA and ammonia monooxygenase (amoA) genes were used to characterize the heterotrophic and ammonia-oxidizing bacteria collected from the biofilter during a 102-day experiment. The overall diversity of the heterotrophic microbial population appeared to decrease by 38% at the end of the experiment. The community structure of the heterotrophic population also shifted from predominantly members of two subdivisions of the Proteobacteria (the beta and gamma subdivisions) to members of one subdivision (the gamma subdivision). An overall decrease in the diversity of ammonia monooxygenase genes was not observed. However, a shift from groups dominated by organisms containing Nitrosomonas-like and Nitrosospira-like amoA genes to groups dominated by organisms containing only Nitrosospira-like amoA genes was observed. In addition, a new amoA gene was discovered. This new gene is the first freshwater amoA gene that is closely affiliated with Nitrosococcus oceanus and the particulate methane monooxygenase gene from the methane oxidizers belonging to the gamma subdivision of the Proteobacteria.

  12. Treatment of xylene polluted air using press mud-based biofilter.

    PubMed

    Saravanan, V; Rajamohan, N

    2009-03-15

    In the present work, biofiltration of xylene vapors has been investigated on a laboratory scale biofilter packed with press mud as filter material inoculated with activated sludge from pharmaceutical industry. Four various gas flow rates, i.e. 0.03, 0.06, 0.09 and 0.12 m(3) h(-1), were tested for inlet xylene concentration ranging from 0.2 to 1.2 g m(-3). The biofilter proved to be highly efficient in the removal of xylene at a gas flow rate of 0.2m(3) h(-1) corresponding to a gas residence time of 2.8 min. For all the tested inlet concentrations, the removal efficiency decreased for high gas flow rates. For all the tested gas flow rates, a decrease in the removal efficiency was noticed for high xylene inlet concentration. The follow-up of carbon dioxide concentration profile through the biofilter revealed that the mass ratio of carbon dioxide produced to the xylene removed was approximately 2.52, which confirms complete degradation of xylene if one considers the fraction of the consumed organic carbon used for the microbial growth.

  13. Methane oxidation in biofilters measured by mass-balance and stable isotope methods.

    PubMed

    Powelson, D K; Chanton, J P; Abichou, T

    2007-01-15

    Simultaneous flux and isotope measurements on compost and sand biofilters showed that the fraction of CH4 oxidized, calculated from delta13C measurements using a closed system model (f(oxir,C)), averaged only 0.455 of the fraction oxidized based on mass-balance measurements (f(oxm)). The discrepancy between f(oxm) and f(oxir,C) may be partly due to complete oxidation of a portion of the inflow gas, thereby eliminating its contribution to the emitted methane on which isotopic measurements are conducted. To relate f(oxir,C) and f(oxm) a simple binary closed-system model is proposed that assumes that f(oxir,C) refers to only part of the inflow, P, and that the remainder of inflow (1 - P) is completely oxidized before reaching the outlet. This model is compared to the standard open-system model. The H-isotope fraction oxidized (f(oxir,H)) was determined for a subset of samples and found to be not significantly different from f(oxir,C). The carbon isotope fractionation factor, alphaox,C = 1.0244, and the H-isotope fractionation factor, alphaox,H = 1.2370, were determined by incubation studies. Delta13C measurements indicated that the emitted flow was more strongly oxidized by the compost biofilters (f(oxir,C) = 0.362, f(oxm) = 0.757) than the sand biofilters (f(oxir,C) = 0.222, f(oxm) = 0.609).

  14. Performance of a biofilter system with agave fiber filter media for municipal wastewater treatment.

    PubMed

    Vigueras-Cortés, Juan Manuel; Villanueva-Fierro, Ignacio; Garzón-Zúñiga, Marco Antonio; de Jesús Návar-Cháidez, José; Chaires-Hernández, Isaías; Hernández-Rodríguez, César

    2013-01-01

    Agave plants grow in semi-arid regions and are used for mescal production. However, agave fiber by-products are considered waste materials. Thus, we tested agave fiber as a filter media and biofilm material carrier for removing pollutants from municipal wastewater. Three laboratory-scale biofiltration reactors were used in two trials with five hydraulic loading rates (HLRs = 0.27, 0.54, 0.80, 1.07 and 1.34 m(3) m(-2) d(-1)). One series was conducted using mechanical aeration (0.62 m(3) m(-2) h(-1)). To prevent compaction, decreasing pressure and clogging of the filter media, 4, 8 and 12 internal divisions were evaluated in the biofilter column. After 17 months of continuous operation at an HLR of 0.80 m(3) m(-2) d(-1), the removal efficiencies of the aerated biofilters were 92.0% biochemical oxygen demand, 79.7% chemical oxygen demand, 98.0% helminth eggs, 99.9% fecal coliforms and 91.9% total suspended solids. Statistical analysis showed that the chosen operational parameters significantly influenced the removal efficiencies of the biofilters. The effluent quality obtained under these conditions complied with the Mexican and US EPA standards for agricultural irrigation and green spaces, except for coliforms, which is why the effluents must be disinfected. Thus, agave fiber is a favorable choice for use as a packing material in biofiltration processes.

  15. Characterization of the microbial community structure and nitrosamine-reducing isolates in drinking water biofilters.

    PubMed

    Wang, Wanfeng; Guo, Yanling; Yang, Qingxiang; Huang, Yao; Zhu, Chunyou; Fan, Jing; Pan, Feng

    2015-07-15

    Two biofilters were constructed using biological activated carbon (BAC) and nitrosamine-containing water from two drinking water treatment plants. The microbiome of each biofilter was characterized by 454 high-throughput pyrosequencing, and one nitrosamine-reducing bacterium was isolated. The results showed that nitrosamines changed the relative abundance at both the phylum and class levels, and the new genera were observed in the microbial communities of the two BAC filters after cultivation. As such, the genus Rhodococcus, which includes many nitrosamine-reducing strains reported in previous studies, was only detected in the BAC2 filter after cultivation. These findings indicate that nitrosamines can significantly affect the genus level in the microbial communities. Furthermore, the isolated bacterial culture Rhodococcus cercidiphylli A41 AS-1 exhibited the ability to reduce five nitrosamines (N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodi-n-propylamine, N-nitrosopyrrolidine, and N-nitrosodi-n-butylamine) with removal ratios that ranged from 38.1% to 85.4%. The isolate exhibited a better biodegradation ability with nitrosamine as the carbon source when compared with nitrosamine as the nitrogen source. This study increases our understanding of the microbial community in drinking water biofilters with trace quantities of nitrosamines, and provides information on the metabolism of nitrosamine-reducing bacteria. Copyright © 2015. Published by Elsevier B.V.

  16. Assessment of changes in microbial community structure during operation of an ammonia biofilter with molecular tools

    NASA Technical Reports Server (NTRS)

    Sakano, Y.; Kerkhof, L.; Janes, H. W. (Principal Investigator)

    1998-01-01

    Biofiltration has been used for two decades to remove odors and various volatile organic and inorganic compounds in contaminated off-gas streams. Although biofiltration is widely practiced, there have been few studies of the bacteria responsible for the removal of air contaminants in biofilters. In this study, molecular techniques were used to identify bacteria in a laboratory-scale ammonia biofilter. Both 16S rRNA and ammonia monooxygenase (amoA) genes were used to characterize the heterotrophic and ammonia-oxidizing bacteria collected from the biofilter during a 102-day experiment. The overall diversity of the heterotrophic microbial population appeared to decrease by 38% at the end of the experiment. The community structure of the heterotrophic population also shifted from predominantly members of two subdivisions of the Proteobacteria (the beta and gamma subdivisions) to members of one subdivision (the gamma subdivision). An overall decrease in the diversity of ammonia monooxygenase genes was not observed. However, a shift from groups dominated by organisms containing Nitrosomonas-like and Nitrosospira-like amoA genes to groups dominated by organisms containing only Nitrosospira-like amoA genes was observed. In addition, a new amoA gene was discovered. This new gene is the first freshwater amoA gene that is closely affiliated with Nitrosococcus oceanus and the particulate methane monooxygenase gene from the methane oxidizers belonging to the gamma subdivision of the Proteobacteria.

  17. Assessment of changes in microbial community structure during operation of an ammonia biofilter with molecular tools

    SciTech Connect

    Sakano, Y.; Kerkhof, L.

    1998-12-01

    Biofiltration has been used for two decades to remove odors and various volatile organic and inorganic compounds in contaminated off-gas streams. Although biofiltration is widely practiced, there have been few studies of the bacteria responsible for the removal of air contaminants in biofilters. In this study, molecular techniques were used to identify bacteria in a laboratory-scale ammonia biofilter. Both 16S rRNA and ammonia monooxygenase (amoA) genes were used to characterize the heterotrophic and ammonia-oxidizing bacteria collected from the biofilter during a 102-day experiment. The overall diversity of the heterotrophic microbial population appeared to decrease by 38% at the end of the experiment. The community structure of the heterotrophic population also shifted from predominantly members of two subdivisions of the Proteobacteria (the beta and gamma subdivisions) to members of one subdivision (the gamma subdivision). An overall decrease in the diversity of ammonia monooxygenase genes was not observed. However, a shift from groups dominated by organisms containing Nitrosomonas-like and Nitrosospira-like amoA genes to groups dominated by organisms containing only Nitrosospira-like amoA genes was observed. In addition, a new amoA gene was discovered. This new gene is the first freshwater amoA gene that is closely affiliated with Nitrosococcus oceanus and the particulate methane monooxygenase gene from the methane oxidizers belonging to the gamma subdivision of the Proteobacteria.

  18. Dynamic olfactometry and GC-TOFMS to monitor the efficiency of an industrial biofilter.

    PubMed

    Gutiérrez, M C; Martín, M A; Pagans, E; Vera, L; García-Olmo, J; Chica, A F

    2015-04-15

    Biofiltration is the most widely used technique for eliminating odours in waste treatment plants. Volatile organic compounds (VOCs) are among the odorous compounds emitted by waste management plants, and serve as variables to measure odour emissions depending on the type of aeration process used. In this work, we assess the performance of an industrial-scale biofilter where composting is the main source of VOCs and odour emissions. Dynamic olfactometry is the sensorial technique used to determine odour concentration, while gas chromatography-time of flight-mass spectrometry (GC-TOFMS) is used to perform the chemical characterization. This work examines a total of 82 compounds belonging to 15 odorous families of VOCs, particularly mercaptans, sulphur-containing compounds, alcohols and terpenes, among others. Principal component analysis (PCA) is used to assess the influence of each of these families of VOCs on the total variance of the measure with regard to both the input and output flow of the biofilter. Finally, partial least-squares (PLS) regression is used to estimate the odour concentration in each of the samples taken at the inlet and outlet of the biofilter in each of the samples based on the chemical information provided by chromatographic analysis. The study shows that there is an adequate correlation (r=0.9751) between real and estimated odour concentrations, both of which are expressed in European odour units per cubic metre (ou(E)·m(-3)). Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Stormwater biofilter treatment model (MPiRe) for selected micro-pollutants.

    PubMed

    Randelovic, Anja; Zhang, Kefeng; Jacimovic, Nenad; McCarthy, David; Deletic, Ana

    2016-02-01

    Biofiltration systems, also known as bioretentions or rain-gardens, are widely used for treatment of stormwater. In order to design them well, it is important to improve models that can predict their performance. This paper presents a rare model that can simulate removal of a wide range of micro-pollutants from stormwater by biofilters. The model is based on (1) a bucket approach for water flow simulation, and (2) advection/dispersion transport equations for pollutant transport and fate. The latter includes chemical non-equilibrium two-site model of sorption, first-order decay, and volatilization, thus is a compromise between the limited availability of data (on stormwater micro-pollutants) and the required complexity to accurately describe the nature of the phenomenon. The model was calibrated and independently validated on two field data series collected for different organic micro-pollutants at two biofilters of different design. This included data on triazines (atrazine, prometryn, and simazine), glyphosate, and chloroform during six simulated stormwater events. The data included variable and challenging biofilter operational conditions; e.g. variable inflow volumes, dry and wet period dynamics, and inflow pollutant concentrations. The model was able to simulate water flow well, with slight discrepancies being observed only during long dry periods when, presumably, soil cracking occurred. In general, the agreement between simulated and measured pollutographs was good. As with flows, the long dry periods posed a problem for water quality simulation (e.g. simazine and prometryn were difficult to model in low inflow events that followed prolonged dry periods). However, it was encouraging that pollutant transport and fate parameters estimated by the model calibration were in agreement with available literature data. This suggests that the model could probably be adopted for assessment of biofilter performance of other stormwater micro-pollutants (PAHs, phenols

  20. Inside Story of Gas Processes within Stormwater Biofilters: Does Greenhouse Gas Production Tarnish the Benefits of Nitrogen Removal?

    PubMed

    Payne, Emily G I; Pham, Tracey; Cook, Perran L M; Deletic, Ana; Hatt, Belinda E; Fletcher, Tim D

    2017-04-04

    Stormwater biofilters are dynamic environments, supporting diverse processes that act to capture and transform incoming pollutants. However, beneficial water treatment processes can be accompanied by undesirable greenhouse gas production. This study investigated the potential for nitrous oxide (N2O) and methane (CH4) generation in dissolved form at the base of laboratory-scale stormwater biofilter columns. The influence of plant presence, species, inflow frequency, and inclusion of a saturated zone and carbon source were studied. Free-draining biofilters remained aerobic with negligible greenhouse gas production during storm events. Designs with a saturated zone were oxygenated at their base by incoming stormwater before anaerobic conditions rapidly re-established, although extended dry periods allowed the reintroduction of oxygen by evapotranspiration. Production of CH4 and N2O in the saturated zone varied significantly in response to plant presence, species, and wetting and drying. Concentrations of N2O typically peaked rapidly following stormwater inundation, associated with limited plant root systems and poorer nitrogen removal from biofilter effluent. Production of CH4 also commenced quickly but continued throughout the anaerobic interevent period and lacked clear relationships with plant characteristics or nitrogen removal performance. Dissolved greenhouse gas concentrations were highly variable, but peak concentrations of N2O accounted for <1.5% of the incoming total nitrogen load. While further work is required to measure surface emissions, the potential for substantial release of N2O or CH4 in biofilter effluent appears relatively low.

  1. Simultaneous removal of di-(2-ethylhexyl) phthalate and nitrogen in a laboratory-scale pre-denitrification biofilter system.

    PubMed

    Cao, Xiangsheng; Ai, Niyuan; Meng, Xuezheng

    2014-03-01

    This study demonstrated the excellent di-(2-ethylhexyl) phthalate (DEHP) removal performance of a pre-denitrification biofilter system. Experimental results showed that DEHP removal efficiency remained stable while total nitrogen removal efficiency fluctuated with the nitrate recycle ratio changes when the hydraulic loading rate at 1.1m(3)/m(2)h. DEHP removal efficiency increased from 48% to 82% while the hydraulic loading rate increased from 1.1 to 2.2m(3)/m(2)h. DEHP concentration decreased gradually along the wastewater flow direction in the denitrification biofilter and a plug flow model with the reaction order of 5 and the rate constant of 0.54 was obtained. Both the denitrification biofilter and the nitrification biofilter showed similar DEHP removal performance. The overall DEHP removal efficiency of the system was 83.8%, in which biodegradation contributed 72.3%. Biodegradation plays a key role in DEHP removal in the pre-denitrification biofilter system. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. [Effect of phosphorus recovery on phosphorous bioaccumulation/harvesting in an alternating anaerobic/aerobic biofilter system].

    PubMed

    Zhang, Shun; Tian, Qing; Tang, Man-Lin; Li, Fang

    2014-03-01

    To improve the phosphorus (P) removal/recovery efficiency of a biological P removal system, the study used an alternating anaerobic/aerobic biofilter system to treat synthetic domestic sewage with a low carbon (C) to P ratio. The effects of using periodical carbon source amplification for P recovery on the P removal efficiency and the microbial characteristics within the biofilm were investigated. Intracellular storage polymer dyeing, scanning electron microscopy (SEM) observation and fluorescence in situ hybridization (FISH) methods were employed to characterize the changes of microbial communities in the biofilm during three continuous operation cycles of P bio-accumulating-P recovery (PB-PR). The results showed: through three cycles of operation process of PB-PR, the P removal efficiency of biofilter was increased from 60.3%, 82.9%, 86.6% (before P harvesting) to 87.2%, 91.2%, 93.5% (after P harvesting), respectively; the dominant microbial community morphotypes within the biofilter transformed from big cocci to small cocci, bacilli and filamentous and the group of phosphate-accumulating organisms (PAOs) got rising predominance, which was increased from 43% to 70% after three times of PB-PR; the proportion of PAOs in the biofilm increased unceasingly with the height of the up-flow biofilter. The results showed that the periodical carbon source amplification could improve the P removal efficiency of the biofilter and help the PAOs to become the dominant bacteria within the biofilm.

  3. Anaerobic Ammonium-Oxidizing (Anammox) Bacteria and Associated Activity in Fixed-Film Biofilters of a Marine Recirculating Aquaculture System†

    PubMed Central

    Tal, Yossi; Watts, Joy E. M.; Schreier, Harold J.

    2006-01-01

    Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aquaculture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by amplifying 16S rRNA genes by PCR using anammox-selective and universal GC-clamped primers. Separation of amplified PCR products by denaturing gradient gel electrophoresis and sequencing of the different phylotypes revealed a diverse biofilter microbial community. While Planctomycetales were found in all three communities, the anaerobic denitrifying biofilters contained one clone that exhibited high levels of sequence similarity to known anammox bacteria. Fluorescence in situ hybridization studies using an anammox-specific probe confirmed the presence of anammox Planctomycetales in the microbial biofilm from the denitrifying biofilters, and anammox activity was observed in these biofilters, as detected by the ability to simultaneously consume ammonia and nitrite. To our knowledge, this is the first identification of anammox-related sequences in a marine recirculating aquaculture filtration system, and our findings provide a foundation for incorporating this important pathway for complete nitrogen removal in such systems. PMID:16597996

  4. Molecular characterization of microbial populations in full-scale biofilters treating iron, manganese and ammonia containing groundwater in Harbin, China.

    PubMed

    Li, Xiang-kun; Chu, Zhao-rui; Liu, Ya-jun; Zhu, Meng-ting; Yang, Liu; Zhang, Jie

    2013-11-01

    In iron and manganese-containing groundwater treatment for drinking water production, biological filter is an effective process to remove such pollutants. Until now the exact microbial mechanism of iron and manganese removal, especially coupled with other pollutants, such as ammonia, has not been clearly understood. To assess this issue, the performance of a full-scale biofilter located in Harbin, China was monitored over four months. Microbial populations in the biofilter were investigated using T-RFLP and clone library technique. Results suggested that Gallionella, Leptothrix, Nitrospira, Hyphomicrobium and Pseudomonas are dominant in the biofilter and play major roles in the removal of iron, manganese and ammonia. The spatial distribution of microbial populations along the depth of the biofilter demonstrated the stratification of the removal of iron, manganese and ammonia. Additionally, the absence of ammonia-oxidizing bacteria in the biofilter implicated that ammonia-oxidizing archaea might be responsible for the oxidation of ammonia to nitrite. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  5. High loading toluene treatment in a compost based biofilter using up-flow and down-flow swing operation.

    PubMed

    Znad, Hussein T; Katoh, Kyohei; Kawase, Yoshinori

    2007-03-22

    A compost/ceramic (1:1, v/v) three section laboratory-scale biofilter inoculated with acclimated activated sludge was examined to treat high loading toluene vapors from a synthetic gas stream. The biofilter was operated continuously at different gas flow rates, 0.108-0.15m(3)h(-1), with inlet toluene concentrations ranging 0.5-13gm(-3). The overall performance of the biofilter was divided to seven stages according to the mode of operation (down-flow and up-flow) over a period of 102 days. Removal efficiencies ranging from 48 to 100% and elimination capacities ranging from 26 to 180gm(-3)h(-1) were observed depending on the initial loading rates and the mode of operations. A maximum elimination capacity of 180gm(-3)h(-1) was observed in the last period at an inlet toluene concentration of about 13gm(-3). The results showed that changing the mode of operation (up-flow and down-flow) periodically will improve the performance of the biofilter under high inlet toluene concentration (higher than 4gm(-3)). Results obtained in this study provide insight into the possibility of the biofilter to treat high inlet concentrations rather than low concentrations well known in the literature.

  6. Anaerobic ammonium-oxidizing (anammox) bacteria and associated activity in fixed-film biofilters of a marine recirculating aquaculture system.

    PubMed

    Tal, Yossi; Watts, Joy E M; Schreier, Harold J

    2006-04-01

    Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aquaculture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by amplifying 16S rRNA genes by PCR using anammox-selective and universal GC-clamped primers. Separation of amplified PCR products by denaturing gradient gel electrophoresis and sequencing of the different phylotypes revealed a diverse biofilter microbial community. While Planctomycetales were found in all three communities, the anaerobic denitrifying biofilters contained one clone that exhibited high levels of sequence similarity to known anammox bacteria. Fluorescence in situ hybridization studies using an anammox-specific probe confirmed the presence of anammox Planctomycetales in the microbial biofilm from the denitrifying biofilters, and anammox activity was observed in these biofilters, as detected by the ability to simultaneously consume ammonia and nitrite. To our knowledge, this is the first identification of anammox-related sequences in a marine recirculating aquaculture filtration system, and our findings provide a foundation for incorporating this important pathway for complete nitrogen removal in such systems.

  7. Treatment of gaseous toluene in three biofilters inoculated with fungi/bacteria: Microbial analysis, performance and starvation response.

    PubMed

    Cheng, Zhuowei; Lu, Lichao; Kennes, Christian; Yu, Jianming; Chen, Jianmeng

    2016-02-13

    Bacteria and fungi are often utilized for the biodegradation of organic pollutants. This study compared fungal and/or bacterial biofiltration in treating toluene under both steady and unsteady states. Fungal biofilter (F-BF) removed less toluene than both bacterial biofilters (B-BF) and fungal & bacterial biofilters (F&B-BF) (<20% vs >60% vs >90%). The mineralization ratio was also lower in F-BF-levels were 2/3 and 1/2 of those values obtained by the other biofilters. Microbial analysis showed that richer communities were present in B-BF and F&B-BF, and that the Hypocreales genus which Trichoderma viride belongs to was much better represented in F&B-BF. The F&B-BF also supported enhanced robustness after 15-day starvation episodes; 1 day later the performance recovered to 80% of the original removal level. The combination of bacteria and fungi makes biofiltration a good option for VOC treatment including better removal and performance stability versus individual biofilters (bacteria or fungi dominated).

  8. Kinetics of the removal of mono-chlorobenzene vapour from waste gases using a trickle bed air biofilter.

    PubMed

    Mathur, Anil K; Sundaramurthy, J; Balomajumder, C

    2006-10-11

    The performance of a trickle bed air biofilter (TBAB) in the removal of mono-chlorobenzene (MCB) was evaluated in concentrations varying from 0.133 to 7.187 g m(-3) and at empty bed residence time (EBRT) varying from 37.7 to 188.52 s. More than 90% removal efficiency in the trickle bed air biofilter was achieved for the inlet MCB concentration up to 1.069 g m(-3) and EBRT less than 94.26 s. The trickle bed air biofilter was constructed with coal packing material, inoculated with a mixed consortium of activated sludge obtained from sewage treatment plant. The continuous performance of the removal of MCB in the trickle bed air biofilter was monitored for various gas concentrations, gas flow rates, and empty bed residence time. The experiment was conducted for a period of 75 days. The trickle bed air biofilter degrading MCB with an average elimination capacity of 80 g m(-3) h(-1) was obtained. The effect of starvation was also studied. After starvation period of 8 days, the degradation was low but recovered within a short period of time. Using macrokinetic determination method, the Michaelis-Menten kinetic constant K(m) and maximum reaction rate, r(max) evaluated as 0.121 g m(-3) s(-1) and 7.45 g m(-3), respectively.

  9. Transrapid und Rad-Schiene-Hochgeschwindigkeitsbahn: Ein gesamtheitlicher Systemvergleich

    NASA Astrophysics Data System (ADS)

    Schach, R.; Jehle, P.; Naumann, R.

    Der Transrapid bietet im Hochgeschwindigkeitsbereich eine sehr interessante Alternative. Über Vor-und Nachteile des Transrapid im Vergleich mit konventionellen Rad-Schiene-Systemen, im Hochgeschwindigkeitsbereich auf Strecken zwischen 150 und 800 Kilometernund als peer-to-peer-Verbindung im Kurzstreckenbereich, wurden viele einze lne Aspekte behandelt, darunter sachliche wie politische Statements. Ein Systemvergleich muß aber alle technischen, wirtschaftlichen und ökologischen Faktoren einschließen.

  10. Autotrophic nitrogen removal process in a potable water treatment biofilter that simultaneously removes Mn and NH4(+)-N.

    PubMed

    Cai, Yan'an; Li, Dong; Liang, Yuhai; Zeng, Huiping; Zhang, Jie

    2014-11-01

    Ammonia (NH4(+)-N) removal pathways were investigated in a potable water treatment biofilter that simultaneously removes manganese (Mn) and NH4(+)-N. The results indicated a significant loss of nitrogen in the biofilter. Both the completely autotrophic nitrogen removal over nitrite (CANON) process and nitrification were more likely to contribute to NH4(+)-N removal. Moreover, the model calculation results demonstrated that the CANON process contributed significantly to the removal of NH4(+)-N. For influent NH4(+)-N levels of 1.030 and 1.749mg/L, the CANON process contribution was about 48.5% and 46.6%, respectively. The most important finding was that anaerobic ammonia oxidation (ANAMMOX) bacteria were detectable in the biofilter. It is interesting that the CANON process was effective even for such low NH4(+)-N concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Continuous deodorization and bacterial community analysis of a biofilter treating nitrogen-containing gases from swine waste storage pits.

    PubMed

    Ho, Kuo-Ling; Chung, Ying-Chien; Tseng, Ching-Ping

    2008-05-01

    A biofilter inoculated with Arthrobacter sp. was applied to the simultaneous elimination of trimethylamine (TMA) and ammonia (NH3) from the exhaust air of swine waste storage pits. The results showed that the biofilter achieved average removal efficiencies of 96.8+/-2.5% and 97.2+/-2.3% for TMA and NH3, respectively. A near-neutral pH (7.3-7.4) was maintained due to the accumulation of acid metabolites and the adsorption of alkaline NH3. Low moisture demand, low pressure drop and high biofilm stability in the system were other advantages. After long-term operation, the bacterial community structure showed that at least twenty-five bands were explicitly detected by a denaturing gradient gel electrophoresis (DGGE) method. However, the inoculated Arthrobacter sp. still maintained a dominant population (>50%). Paracoccus denitrificans' presence in the biofilter could play an important role in oxidizing NH3 and reducing nitrite by heterotrophic nitrification and anaerobic denitrification.

  12. Performance of a biofilter for the removal of high concentrations of styrene under steady and non-steady state conditions.

    PubMed

    Rene, Eldon R; Veiga, María C; Kennes, Christian

    2009-08-30

    The performance of a laboratory scale perlite biofilter inoculated with a mixed culture was evaluated for gas phase styrene removal under various operating conditions. Experiments were carried out by subjecting the biofilter to different flow rates (0.15-0.9 m(3)h(-1)) and concentrations (0.03-17.3 gm(-3)), corresponding to inlet loading rates varying from as low as 3 gm(-3)h(-1) to as high as 1390 gm(-3)h(-1). A maximum elimination capacity (EC) of 382 gm(-3)h(-1) was achieved at an inlet loading rate of 464 gm(-3)h(-1) with a removal efficiency of 82%. The high elimination capacity reached with this system could have been due to the dominant presence of filamentous fungi among others. The impact of relative humidity (RH) (30%, 60% and >92%) on the biofilter performance was evaluated at two constant loading rates, viz., 80 and 260 gm(-3)h(-1), showing that inhibitory effects were only significant when combining the highest loads with the lowest relative humidities. Biomass distribution, moisture content and concentration profiles along the bed height were significantly dependent on the relative humidity of the inlet air and on the loading rate. The dynamic behaviour of the biofilter through vigorous short and long-term shock loads was tested at different process conditions. The biofilter was found to respond apace to rapid changes in loading conditions. The stability of the biomass within the reactor was apparent from the fast response of the biofilter to recuperate and handle intermittent shutdown and restart operations, either with or without nutrient addition.

  13. Potentialities of coupling biological processes (biotrickler/biofilter) for the degradation of a mixture of sulphur compounds.

    PubMed

    Malhautier, Luc; Soupramanien, Alexandre; Bayle, Sandrine; Rocher, Janick; Fanlo, Jean-Louis

    2015-01-01

    This study deals with the potential of biological processes combining a biotrickler and a biofilter to treat a mixture of sulphur-reduced compounds including dimethyl sulphide (DMS), dimethyl disulphide (DMDS) and hydrogen sulphide (H2S). As a reference, duplicated biofilters were implemented, and operating conditions were similar for all bioprocesses. The first step of this work was to determine the efficiency removal level achieved for each compound of the mixture and in a second step, to assess the longitudinal distribution of biodegradation activities and evaluate the total bacteria, Hyphomicrobium sp. and Thiobacillus thioparus densities along the bed height. A complete removal of hydrogen sulphide is reached at the start of the experiment within the first stage (biotrickler) of the coupling. This study highlighted that the coupling of a biotrickling filter and a biofilter is an interesting way to improve both removal efficiency levels (15-20% more) and kinetics of recalcitrant sulphur compounds such as DMS and DMDS. The total cell densities remained similar (around 1 × 10(10) 16S recombinant DNA (rDNA) copies g dry packing material) for duplicated biofilters and the biofilter below the biotrickling filter. The relative abundances of Hyphomicrobium sp. and T. thioparus have been estimated to an average of 10 ± 7.0 and 0.23 ± 0.07%, respectively, for all biofilters. Further investigation should allow achieving complete removal of DMS by starting the organic sulphur compound degradation within the first stage and surveying microbial community structure colonizing this complex system.

  14. Steady state and dynamic behaviors of a methane biofilter under periodic addition of ethanol vapors.

    PubMed

    Ferdowsi, Milad; Avalos Ramirez, Antonio; Jones, J Peter; Heitz, Michèle

    2017-07-15

    Ethanol was added to a methane (CH4) biofilter with inorganic packing materials over three cycles based on increasing the gas flow rates from 3 to 6 and finally to 12 L min(-1) corresponding to empty bed residence times (EBRT) of 6, 3 and 1.5 min. The steady state performance of the CH4 biofilter was studied for CH4 inlet loads (ILs) of 33, 66 and 132 gCH4 m(-3) h(-1) prior and after each ethanol cycle. In addition, the steady state removal of a mixture of CH4 and ethanol for a CH4/ethanol mass ratio of around 7.5 gCH4 g (-1)ethanol was evaluated over three cycles (EBRTs of 6, 3 and 1.5 min). In the absence of ethanol, the CH4 removal efficiency (RE) dropped from 35 to 7% due to an EBRT decrease from 6 to 1.5 min. In addition, the presence of ethanol resulted in a CH4 RE reduction at a constant EBRT in every cycle. The CH4 REs dropped from 35 to 29%, 17 to 13% and 7 to 0% for corresponding ethanol ILs of 4.5, 9 and 18 gethanol m(-3) h(-1) over the cycles. Moreover, the periodic presence of ethanol in the CH4 biofilter allowed the study of transient behaviors of the biofilter during ethanol addition and the biofilter recovery after each cycle. The CH4 RE reduction as a result of ethanol addition in each cycle was instantaneous. However, the CH4 RE recovery after completion of ethanol addition took 10, 14 and 25 days for ethanol ILs of 4.5, 9 and 18 gethanol m(-3) h(-1) respectively. The recovery time was related to the ethanol concentration in the leachate which were 1100 ± 200, 1100 ± 350 and 2500 ± 400 gethanol m(-3)leachate for corresponding ethanol ILs of 4.5, 9 and 18 gethanol m(-3) h(-1), respectively. Based on steady state and dynamic process conditions of the biofilter, the lowest gas flow rate of 3 L min(-1) (EBRT of 6 min) produced the best performance when both pollutants were present (CH4 IL of 33 gCH4 m(-3) h(-1) and ethanol IL of 4.5 gethanol m(-3) h(-1)). Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Degradation characteristics of methyl ethyl ketone by Pseudomonas sp. KT-3 in liquid culture and biofilter.

    PubMed

    Lee, Tae Ho; Kim, Jaisoo; Kim, Min-Joo; Ryu, Hee Wook; Cho, Kyung-Suk

    2006-04-01

    With ketone pollution forming an ever-growing problem, it is important to identify a ketone-degrading microorganism and establish its effect. Here, a methyl ethyl ketone (MEK)-degrading bacterium, Pseudomonas sp. KT-3, was isolated and its MEK degradation characteristics were examined in liquid cultures and a polyurethane-packed biofilter. In liquid cultures, strain KT-3 could degrade other ketone solvents, including diethyl ketone (DK), methyl propyl ketone (MPK), methyl isopropyl ketone (MIPK), methyl isobutyl ketone (MIBK), methyl butyl ketone (MBK) and methyl isoamyl ketone (MIAK). The maximum specific growth rate (mumax) of the isolate was 0.136 h(-1) in MEK medium supplemented with MEK as a sole carbon source, and kinetically, the maximum removal rate (Vm) and saturation constant (Km) for MEK were 12.28 mM g(-1)DCW h(-1) (DCW: dry cell weight) and 1.64 mM, respectively. MEK biodegradation by KT-3 was suppressed by the addition of MIBK or acetone, but not by toluene. In the tested biofilter, KT-3 exhibited a>90% removal efficiency for MEK inlet concentrations of around 500 ppmv at a space velocity (SV) of 150 h(-1). The elimination capacity of MEK was more influenced by SV than by the inlet concentration. Kinetic analysis showed that the maximum MEK removal rate (Vm) was 690 g m(-3) h(-1) and the saturation constant (Km) was 490 ppmv. Collectively, these results indicate the polyurethane sequencing batch biofilter with Pseudomonas sp. KT-3 will provide an excellent performance in the removal of gaseous MEK.

  16. In vitro methane removal by volcanic pumice soil biofilter columns over one year.

    PubMed

    Pratt, Chris; Walcroft, Adrian S; Tate, Kevin R; Ross, Des J; Roy, Réal; Reid, Melissa Hills; Veiga, Patricia W

    2012-01-01

    Soil methane (CH(4)) biofilters, containing CH(4)-oxidizing bacteria (methanotrophs), are a promising technology for mitigating greenhouse gas emissions. However, little is known about long-term biofilter performance. In this study, volcanic pumice topsoils (0-10 cm) and subsoils (10-50 cm) were tested for their ability to oxidize a range of CH(4) fluxes over 1 yr. The soils were sampled from an 8-yr-old and a 2-yr-old grassed landfill cover and from a nearby undisturbed pasture away from the influence of CH(4) generated by the decomposing refuse. Methane was passed through the soils in laboratory chambers with fluxes ranging from 0.5 g to 24 g CH(4) m(-3) h(-1). All topsoils efficiently oxidized CH(4). The undisturbed pasture topsoil exhibited the highest removal efficiency (24 g CH(4) m(-3) h(-1)), indicating rapid activation of the methanotroph population to the high CH(4) fluxes. The subsoils were less efficient at oxidizing CH(4) than the topsoils, achieving a maximum rate oxidation rate of 7 g CH(4) m(-3) h(-1). The topsoils exhibited higher porosities; moisture contents; surface areas; and total C, N, and available-P concentrations than the subsoils, suggesting that these characteristics strongly influence growth and activity of the CH(4)-oxidizing bacteria. Soil pH values and available-P levels gradually declined during the trial, indicating a need to monitor chemical parameters closely so that adjustments can be made when necessary. However, other key soil physicochemical parameters (moisture, total C, total N) increased over the course of the trial. This study showed that the selected topsoils were capable of continually sustaining high CH(4) removal rates over 1 yr, which is encouraging for the development of biofilters as a low-maintenance greenhouse gas mitigation technology. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  17. Microbial succession in a compost-packed biofilter treating benzene-contaminated air.

    PubMed

    Borin, Sara; Marzorati, Massimo; Brusetti, Lorenzo; Zilli, Mario; Cherif, Hanene; Hassen, Abdennaceur; Converti, Attilio; Sorlini, Claudia; Daffonchio, Daniele

    2006-03-01

    Air artificially contaminated with increasing concentrations of benzene was treated in a laboratory scale compost-packed biofilter for 240 days with a removal efficiency of 81-100%. The bacterial community in the packing material (PM) at different heights of the biofilter was analysed every 60 days. Bacterial plate counts and ribosomal intergenic spacer analysis (RISA) of the isolated strains showed that the number of cultivable aerobic heterotrophic bacteria and the species diversity increased with benzene availability. Identification of the isolated species and the main bands in denaturing gradient gel electrophoresis (DGGE) profiles from total compost DNA during the treatment revealed that, at a relatively low volumetric benzene load (1.2< or =VBL< or =6.4 g m(-3) (PM) h(-1)), besides low G+C Gram positive bacteria, originally present in the packing compost, bacteroidetes and beta- and gamma-proteobacteria became detectable in the colonising population. At the VBL value (24.8 g m(-3) (PM) h(-1)) ensuring the maximum elimination capacity of the biofilter (20.1 g m(-3) (PM) h(-1)), strains affiliated to the genus Rhodococcus dominated the microflora, followed by beta-proteobacteria comprising the genera Bordetella and Neisseria. Under these conditions, more than 35% of the isolated strains were able to grow on benzene as the sole carbon source. Comparison of DGGE and automated RISA profiles of the total community and isolated strains showed that a complex bacterial succession occurred in the reactor in response to the increasing concentrations of the pollutant and that cultivable bacteria played a major role in benzene degradation under the adopted conditions.

  18. A lava rock-based biofilter for the treatment of alpha-pinene.

    PubMed

    Langolf, B M; Kleinheinz, G T

    2006-10-01

    Biofiltration is an emerging technology in the United States that utilizes microorganisms to biodegrade harmful contaminants in air to carbon dioxide and water. Biofiltration is not only more cost effective, but also more environmentally friendly than traditional technologies such as thermal oxidation and chemical scrubbing. The primary objectives of the study were to operate a lava rock-based laboratory biofiltration system for the removal of alpha-pinene. A consortium of microorganisms to be used as an inoculum was recovered that was able to use alpha-pinene as a sole source of carbon and energy. The removal of alpha-pinene from the laboratory system was monitored with a total hydrocarbon analyzer (THA). Based on THA analysis, elimination capacities as high as 100+g/m(3)/h were obtained in the laboratory biofilters. Removal efficiencies averaged 99% over a two year period. The solid support maintained a neutral pH with no buffer addition throughout the two year study and microbial levels were maintained between 10(6) and 10(7) colony forming units (CFU)/g of solid support. Bacillus and Rhodococcus species were found to be the majority of the microorganisms in the biofilters over a two year period. This is the first time an organism from either of these genera has been reported to utilize alpha-pinene as a sole source of carbon and energy. Overall, a preselected consortium of microorganisms coupled with lava rock as a biofilter solid support achieved extended alpha-pinene treatment levels that far exceed previously published values.

  19. Effect of switching gas inlet position on the performance of a polyurethane biofilter under transient loading for the removal of benzene, toluene and xylene mixtures.

    PubMed

    Lee, Eun-Hee; Ryu, Hee Wook; Cho, Kyung-Suk

    2011-01-01

    The performance of a polyurethane (PU) biofilter was evaluated using different operating modes (unidirectional flow (UF) and flow-directional switching (FDS) operations) under transient loading conditions (intermittent and shutdown). Gas mixtures containing benzene, toluene and xylene (BTX) were employed as model gases. Quantitative real-time PCR methods were used for targeting the tmoA gene responsible for BTX degradation and estimating density of the BTX-degraders in the PU filter bed. Although the overall BTX Removal efficiencies at the outlet (50 h(-1) of space velocity) were similar between the UF and FDS biofilters, the removability of BTX in the FDS biofilter was higher than that in the UF biofilter until the 3rd sampling position (68 h(-1) of space velocity). The BTX removal potentials and tmoA gene copy numbers of the FDS biofilter remained constant, irrespective of the distances from the inlet, but those of the UF biofilter increased with increasing distance from the inlet position. These results indicate that an even distribution of BTX degraders in the FDS filter bed contributed to better BTX removal performance. After a 10 day-shutdown, the performances of the UF and SDF biofilters were rapidly restored within 1 day.

  20. H2S removal and bacterial structure along a full-scale biofilter bed packed with polyurethane foam in a landfill site.

    PubMed

    Li, Lin; Han, Yunping; Yan, Xu; Liu, Junxin

    2013-11-01

    Hydrogen sulfide accumulated under a cover film in a landfill site was treated for 7 months by a full-scale biofilter packed with polyurethane foam cubes. Sampling ports were set along the biofilter bed to investigate H2S removal and microbial characteristics in the biofilter. The H2S was removed effectively by the biofilter, and over 90% removal efficiency was achieved in steady state. Average elimination capacity of H2S was 2.21 g m(-3) h(-1) in lower part (LPB) and 0.41 g m(-3) h(-1) in upper part (UPB) of the biofilter. Most H2S was eliminated in LPB. H2S concentration varied along the polyurethane foam packed bed, the structure of the bacterial communities showed spatial variation in the biofilter, and H2S removal as well as products distribution changed accordingly. The introduction of odorants into the biofilter shifted the distribution of the existing microbial populations toward a specific culture that could metabolize the target odors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. [Efficacy of the analytic approach in evaluation of biofilter activity in a composting system].

    PubMed

    Fiore, Maria; Cicciù, Francesca; Cunsolo, Maria; Fallico, Roberto; Sciacca, Salvatore; Ferrante, Margherita

    2011-01-01

    Composting may present certain technical problems which can negatively influence results in terms of environmental impact as well as of profit and loss account. The aim of this study was to estimate the efficacy of the analytic approach to evaluate the effect of removing the biofilter in a composting system. Results have shown the presence of foul-smelling emissions despite the fact that concentrations of investigated substances were well below the danger threshold or even below the method's detection threshold. Therefore, besides the analytic approach, the most reasonable choice seems to be introducing a reference method for evaluating odour emissions and the efficacy of composting systems.

  2. Removal of toluene vapour using agro-waste as biofilter media.

    PubMed

    Singh, R S; Agnihotri, S S; Upadhyay, S N

    2006-12-01

    Biodegradation of toluene vapour was investigated in a laboratory scale biofilter packed with cylindrical pieces of yellow-gram (Cajanus cajan) stalk. Inlet concentrations and volumetric flow rates of toluene were varied from 2.56 to 34.73 g/m3 and 0.18 to 0.24 m3/h, respectively. The steady state was achieved within seven days and the degradation of toluene followed an exponential behaviour with time. Elimination capacity increased and tended towards a constant value but removal efficiency decreased with increase in inlet toluene loading. Depending upon loading rate, the process was either mass transfer or reaction-controlled.

  3. Evaluating the impact of water supply strategies on p-xylene biodegradation performance in an organic media-based biofilter.

    PubMed

    Gallastegui, G; Muñoz, R; Barona, A; Ibarra-Berastegi, G; Rojo, N; Elías, A

    2011-01-30

    The influence of water irrigation on both the long-term and short-term performance of p-xylene biodegradation under several organic loading scenarios was investigated using an organic packing material composed of pelletised sawdust and pig manure. Process operation in a modular biofilter, using no external water supply other than the moisture from the saturated inlet air stream, showed poor p-xylene abatement efficiencies (≈33 ± 7%), while sustained irrigation every 25 days rendered a high removal efficiency (RE) for a critical loading rate of 120 g m(-3)h(-1). Periodic profiles of removal efficiency, temperature and moisture content were recorded throughout the biofilter column subsequent to each biofilter irrigation. Hence, higher p-xylene biodegradation rates were always initially recorded in the upper module, which resulted in a subsequent increase in temperature and a decrease in moisture content. This decrease in the moisture content in the upper module resulted in a higher removal rate in the middle module, while the moisture level in the lower module steadily increased as a result of water condensation. Based on these results, mass balance calculations performed using measured bed temperatures and relatively humidity values were successfully used to account for water balances in the biofilter over time. Finally, the absence of bed compaction after 550 days of continuous operation confirmed the suitability of this organic material for biofiltration processes. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. Stabilization of Stormwater Biofilters: Impacts of Wetting and Drying Phases and the Addition of Organic Matter to Filter Media.

    PubMed

    Subramaniam, D N; Egodawatta, P; Mather, P; Rajapakse, J P

    2015-09-01

    Ripening period refers to a phase of stabilization in sand filters in water treatment systems that follow a new installation or cleaning of the filter. Intermittent wetting and drying, a unique property of stormwater biofilters, would similarly be subjected to a phase of stabilization. Suspended solids are an important parameter that is often used to monitor the stabilization of sand filters in water treatment systems. Stormwater biofilters, however, contain organic material that is added to the filter layer to enhance nitrate removal, the dynamics of which is seldom analyzed in stabilization of stormwater biofilters. Therefore, in this study of stormwater biofiltration in addition to suspended solids (turbidity), organic matter (TOC, DOC, TN, and TKN) was also monitored as a parameter for stabilization of the stormwater biofilter. One Perspex bioretention column (94 mm internal diameter) was fabricated with filter layer that contained 8 % organic material and fed with tapwater with different antecedent dry days (0-40 day) at 100 mL/min. Samples were collected from the outflow at different time intervals between 2 and 150 min and were tested for total organic carbon, dissolved organic carbon, total nitrogen, total Kjeldhal nitrogen, and turbidity. The column was observed to experience two phases of stabilization, one at the beginning of each event that lasted for 30 min, while the other phase was observed across subsequent events that are related to the age of filter.

  5. Stabilization of Stormwater Biofilters: Impacts of Wetting and Drying Phases and the Addition of Organic Matter to Filter Media

    NASA Astrophysics Data System (ADS)

    Subramaniam, D. N.; Egodawatta, P.; Mather, P.; Rajapakse, J. P.

    2015-09-01

    Ripening period refers to a phase of stabilization in sand filters in water treatment systems that follow a new installation or cleaning of the filter. Intermittent wetting and drying, a unique property of stormwater biofilters, would similarly be subjected to a phase of stabilization. Suspended solids are an important parameter that is often used to monitor the stabilization of sand filters in water treatment systems. Stormwater biofilters, however, contain organic material that is added to the filter layer to enhance nitrate removal, the dynamics of which is seldom analyzed in stabilization of stormwater biofilters. Therefore, in this study of stormwater biofiltration in addition to suspended solids (turbidity), organic matter (TOC, DOC, TN, and TKN) was also monitored as a parameter for stabilization of the stormwater biofilter. One Perspex bioretention column (94 mm internal diameter) was fabricated with filter layer that contained 8 % organic material and fed with tapwater with different antecedent dry days (0-40 day) at 100 mL/min. Samples were collected from the outflow at different time intervals between 2 and 150 min and were tested for total organic carbon, dissolved organic carbon, total nitrogen, total Kjeldhal nitrogen, and turbidity. The column was observed to experience two phases of stabilization, one at the beginning of each event that lasted for 30 min, while the other phase was observed across subsequent events that are related to the age of filter.

  6. Succession of microorganisms in a plate-type air treatment biofilter during filtration of various volatile compounds.

    PubMed

    Repečkienė, Jūratė; Švedienė, Jurgita; Paškevičius, Algimantas; Tekorienė, Rūta; Raudonienė, Vita; Gudeliūnaitė, Eglė; Baltrėnas, Pranas; Misevičius, Antonas

    2015-01-01

    Changes in the number and species diversity of cultivable microorganisms in a newly developed plate-type biofilter during filtration of various volatile pollutants were studied. The novelty of the investigation is the monitoring of microorganism succession in different parts of biofilter plates with original packing material consisting of birch fibre and needle-punched non-woven fabric. It was shown that the largest number of fungi and yeasts develop on the top and middle, while bacteria develop on the bottom and middle parts of plates. The number of microorganisms depends on the origin of the pollutant, the pH and temperature inside the biofilter and the moisture of the porous plates. The statistically significant correlation between the number of microorganisms and inlet concentration of acetone was estimated, while ammonia showed a negative influence on yeast distribution. Paecilomyces variotii, Rhodotorula mucilaginosa and Bacillus subtilis were the most common organisms found during filtration of all examined volatiles; however, some differences of microbial communities in different parts of the biofilter plates and filtrated volatile compounds were obtained.

  7. Simultaneous removal of ammonia and hydrogen sulfide gases using biofilter media from the biodehydration stage and curing stage of composting.

    PubMed

    Hou, Jiaqi; Li, Mingxiao; Xia, Tianming; Hao, Yan; Ding, Jie; Liu, Dongming; Xi, Beidou; Liu, Hongliang

    2016-10-01

    Biofiltration of NH3 and H2S with different packing media, biodehydration stage compost (BSC), and curing stage compost (CSC) was studied. Meanwhile, fluorescence excitation-emission matrix (EEM) spectroscopy was used to characterize the conversion mechanisms of organic matter during these biofiltration processes. Both biofilters were effective for the simultaneous removal of NH3 and H2S when inlet concentrations of NH3 and H2S were 0-50 and 50-250 mg/m(3), respectively. An abrupt increase in the inlet gas concentrations of NH3 and H2S to 100-150 and 200-250 mg/m(3), respectively, caused the decrease in the removal efficiencies (REs) of NH3 and H2S in the BSC biofilter, followed by a slow upturn. By contrast, relatively steady REs of both NH3 and H2S were observed in the CSC biofilter. After 60 days of operation, the average REs of NH3 and H2S were more than 95 % in the CSC biofilter. During the operation of CSC, nitrate and nitrite peaked around the 30th day, whereas sulfate showed a steady increase. The excitation-emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC) indicated that the simultaneous inlet of NH3 and H2S facilitated the degradation of protein-like substances, whereas humic-like substances played an important role in the packing filters for the treatment of the two odorous pollutants.

  8. Treatment of mixtures of toluene and n-propanol vapours in a compost-woodchip-based biofilter.

    PubMed

    Dixit, R M; Deshmukh, S C; Gadhe, A A; Kannade, G S; Lokhande, S K; Pandey, R A; Vaidya, A N; Mudliar, S N; Deshusses, M A

    2012-01-01

    The present work describes the biofiltration of mixture of n-propanol (as a model hydrophilic volatile organic compound (VOC)) and toluene (as a model hydrophobic VOC) in a biofilter packed with a compost-woodchip mixture. Initially, the biofilter was fed with toluene vapours at loadings up to 175 g m(-3) h(-1) and removal efficiencies of 70%-99% were observed. The biofilter performance when removing mixtures of toluene and n-propanol reached elimination capacities of up to 67g(toluene) m(-3) h(-1) and 85 g(n-propanol) m(-3) h(-1) with removal efficiencies of 70%-100% for toluene and essentially 100% for n-propanol. The presence of high n-propanol loading negatively affected the toluene removal; however, n-propanol removal was not affected by the presence of toluene and was effectively removed in the biofilter despite high toluene loadings. A model for toluene and n-propanol biofiltration could predict the cross-inhibition effect of n-propanol on toluene removal.

  9. Development and validation of a simple protocol to rapidly determine the performance of biofilters for VOC treatment

    SciTech Connect

    Deshusses, M.A.; Johnson, C.T.

    2000-02-01

    A protocol has been developed for the rapid determination of complete elimination characteristics of target pollutants in waste air biofilters. The protocol involves the determination of two pollutant concentration profiles along the height of a three-segment biofilter under carefully chosen conditions. The combination of the data results in 12 points on the elimination capacity vs load curve which is sufficient to fully characterize a system. The protocol conditions were chosen to enable characterization of biofiltration systems with VOC elimination capacities ranging from 20 to 120 g m{sup {minus}3} h{sup {minus}1}. The protocol was then applied to 18 different VOCs, and the results compared well with previously published data, when available. Maximum removal performance of classes of compounds in the biofilter followed the sequence alcohols > esters > ketones >aromatics alkanes. An attempt was made to correlate the pollutant elimination with Henry's coefficient, and the octanol/water partition coefficient and trends were obtained. The results suggest that biodegradation of VOCs in biofilters is influenced both by the pollutant availability and to a lesser extent by the hydrophobicity of the treated compounds.

  10. Characterisation of hexane-degrading microorganisms in a biofilter by stable isotope-based fatty acid analysis, FISH and cultivation.

    PubMed

    Friedrich, Michèle M; Lipski, André

    2010-01-01

    The hexane-degrading bacterial community of a biofilter was characterised by a combination of stable isotope-based phospholipid fatty acid analyses, fluorescence in situ hybridisation and cultivation. About 70 bacterial strains were isolated from a full-scale biofilter used for treatment of hexane containing waste gas of an oil mill. The isolation approach led to 16 bacterial groups, which were identified as members of the Alpha-, Beta- and Gammaproteobacteria, Actinobacteria and Firmicutes. Three groups showed good growth on hexane as the sole source of carbon. These groups were allocated to the genera Gordonia and Sphingomonas and to the Nevskia-branch of the Gammaproteobacteria. Actively degrading populations in the filter material were characterised by incubation of filter material samples with deuterated hexane and subsequent phospholipid fatty acid analysis. Significant labelling of the fatty acids 16:1 cis10, 18:1 cis9 and 18:0 10methyl affiliated the hexane-degrading activity of the biofilter with the isolates of the genus Gordonia. In vitro growth on hexane and in situ labelling of characteristic fatty acids confirmed the central role of these organisms in the hexane degradation within the full-scale biofilter.

  11. Dynamic volume-averaged model of heat and mass transport within a compost biofilter: I. Model development.

    PubMed

    Mysliwiec, M J; VanderGheynst, J S; Rashid, M M; Schroeder, E D

    2001-05-20

    Successful, long-term operation of a biofilter system depends on maintaining a suitable biofilm environment within a porous medium reactor. In this article a mathematical study was conducted of the spatial and temporal changes of biofilter performance due to interphase heat and mass transport. The method of volume averaging was used to spatially smooth the three-phase (solid, liquid, and gas) conservation equations over the biofilter domain. The packing medium was assumed to be inert, removing the solid phase mass continuity equation from the system. The finite element method was used to integrate the resulting nonlinear-coupled partial differential equations, tracking eight state variables: temperature, water vapor, dry air, liquid water, biofilm, gas and liquid phase organic pollutant, and nutrient densities, through time and space. A multiphase, gas and liquid flow model was adapted to the biofilter model from previous studies of unsaturated groundwater flow. Newton's method accelerated by an LU direct solver was used to iterate the model for solutions. Effects of packing media on performance were investigated to illustrate the utility of the model. The moisture dynamics and nutrient cycling are presented in Part II of this article. Copyright 2001 John Wiley & Sons, Inc.

  12. Simulation eines rekonfigurierbaren Gm-C filter arrays

    NASA Astrophysics Data System (ADS)

    Henrici, F.; Becker, J.; Manoli, Y.

    2007-06-01

    Es wird ein Gm-C Filter für den Einsatz in rekonfigurierbaren Analogfiltern (FPAAs) präsentiert. Das Filter ist auf den Einsatz in FPAAs mit hexagonalem Grid und auf den Verzicht auf Transmissiongates optimiert. Trotzdem können nicht nur die Parameter der instanziierten Filter geändert werden, sondern auch ihre Struktur. Beim Design des digital programmierbaren Transkonduktors musste auf die hohe Anzahl parallel geschalteter, gleichartiger Transkonduktoren und ihre parasitären Kapazitäten Rücksicht genommen werden. Ein FPAA mit 49 Gm-Zellen erreicht in Simulationen in einem 130 nm 1.2 V CMOS Prozess eine maximale Bandbreite von 164 MHz. Die Verzerrung beträgt weniger als -70 dB bei einem 50m V @1 MHz Signal.

  13. Ein routine-integrierbares Planungswerkzeug zur operativen Rekonstruktion der Orbita

    NASA Astrophysics Data System (ADS)

    Kleiner, Melanie; Schulze, Dirk; Voss, Pit Jakob; Deserno, Thomas M.

    Bei Frakturen des Orbitabodens kann ein Titangitter zur Rekonstruktion operativ eingesetzt werden. In dieser Arbeit wird ein Planungswerkzeug entwickelt, welches mit Hilfe eines aktiven Konturmodells die Orbita in CT Daten segmentiert, ihr Volumen berechnet und visualisiert. Neben den technischen Integrationsstufen der Funktions- und Präsentationsintegration, welche durch den Einsatz des Medical Imaging Interaction Toolkit (MITK) erreicht werden, sowie der Daten-, und Kontextintegration ist vor allem die Stabilität der eingesetzten Algorithmik für die Routine-Integrierbarkeit wichtig. Erste Stabilitätsuntersuchungen basieren auf 3 von 100 zufällig ausgewählten CT-Datensätzen, wobei das Volumen mit je 50 verschiedenen Startpunkten berechnet wurde. Die so ermittelten Variationskoeffizienten liegen deutlich unterhalb der kritischen 5 % Schwelle.

  14. Long-term operational studies of lab-scale pumice-woodchip packed stormwater biofilters.

    PubMed

    Cheng, Jing; Yuan, Qingke; Kim, Youngchul

    2017-06-13

    The performance of three pumice-woodchip packed stormwater biofilter (PWSWBF) systems with three packing volume ratios of pumice to woodchip (1:2, 1:1 and 2:1) were compared. The results show that the PWSWBF system packed with a lower percentage of woodchip attained a higher removal efficiency of TCOD, TN, NH4-N and TP, whereas all three systems completely removed nitrate. The highest removal efficiencies for TCOD, TN, NH4-N, NO3-N and TP were 95%, 70%, 86%, 100% and 100%, respectively. In the biofilter with a lower percentage of woodchip, the pollutants that get removed through aerobic biological processes were removed more significantly, which is attributed to less oxygen depletion via woodchip decomposition, which is common under wet conditions. Nitrate was significantly removed via denitrification in all three systems, indicating that the woodchip that occupied one-third of the main media was sufficient for denitrification, and also that the oxygen condition inside the column was proper for denitrification to proceed. A smaller amount of woodchip as the packing material also mitigated the adverse effect of the release of organics from the media during the initial period. In addition, the system showed very good buffering capacity, in that the outflow pH was constant within the optimal range for microorganism growth.

  15. Moisture effects on gas-phase biofilter ammonia removal efficiency, nitrous oxide generation, and microbial communities.

    PubMed

    Yang, Liangcheng; Kent, Angela D; Wang, Xinlei; Funk, Ted L; Gates, Richard S; Zhang, Yuanhui

    2014-04-30

    We established a four-biofilter setup to examine the effects of moisture content (MC) on biofilter performance, including NH3 removal and N2O generation. We hypothesized that MC increase can improve NH3 removal, stimulate N2O generation and alter the composition and function of microbial communities. We found that NH3 removal efficiency was greatly improved when MC increased from 35 to 55%, but further increasing MC to 63% did not help much; while N2O concentration was low at 35-55% MC, but dramatically increased at 63% MC. Decreasing MC from 63 to 55% restored N2O concentration. Examination of amoA communities using T-RFLP and real-time qPCR showed that the composition and abundance of ammonia oxidizers were not significantly changed in a "moisture disturbance-disturbance relief" process in which MC was increased from 55 to 63% and then reduced to 55%. This observation supported the changes of NH3 removal efficiency. The composition of nosZ community was altered at 63% MC and then was recovered at 55% MC, which indicates resilience to moisture disturbance. The abundance of nosZ community was negatively correlated with moisture content in this process, and the decreased nosZ abundance at 63% MC explained the observation of increased N2O concentration at that condition. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Performance evaluation of a scoria-compost biofilter treating xylene vapors.

    PubMed

    Amin, Mohammad Mehdi; Rahimi, Amir; Bina, Bijan; Heidari, Mohsen; Mohammadi Moghadam, Fazel

    2014-01-01

    The removal of xylene vapors was studied in a biofilter packed with a new hybrid (scoria/compost) packing material at various inlet loads (IL) and empty bed residence times (EBRT) of 90, 60, and 40s. The best performance was observed for EBRT of 90s, where a removal efficiency of 98% was obtained under steady state condition for inlet xylene concentration of 1.34 g m(-3), while a maximum elimination capacity of 97.5 g m(-3) h(-1) was observed for IL of 199.5 g m(-3) h(-1). Carbon dioxide production rates and the microbial counts for xylene-degraders followed xylene elimination capacities. Overall look to the results of this study indicates that the scoria/compost mixture could be considered as a potential biofilter carrier, with low pressure drop (here <4 mm H2O), to treat air streams containing VOCs.

  17. Hydraulic performance of biofilter systems for stormwater management: Influences of design and operation

    NASA Astrophysics Data System (ADS)

    Le Coustumer, Sébastien; Fletcher, Tim D.; Deletic, Ana; Barraud, Sylvie; Lewis, Justin F.

    2009-09-01

    SummaryIn order to evaluate the long-term performance of stormwater biofilters, a study was undertaken to assess their hydraulic conductivity. Despite variability in conductivity (40% being below the recommended range of 50-200 mm/h, 43% within it, and 17% above), treatment performance is unlikely to be affected, as most systems are over-sized such that their detention storage volume compensates for reduced media conductivity. The study broadly reveals two types of systems: some with a high initial conductivity (>200 mm/h) and some with a low initial value (<20 mm/h). Significant reduction in conductivity is evident for biofilters in the former group, although most are shown to maintain an acceptably high conductivity. Those with initially low conductivity do not change greatly over time. Site characteristics such as filter area (relative to catchment area), age and inflow volume were not useful predictors of conductivity, with initial conductivity of the original media being the most powerful explanatory variable. It is clear therefore, that strict attention must be paid to the specification of original filter media, to ensure that it satisfies design requirements.

  18. Achieving partial denitrification through control of biofilm structure during biofilm growth in denitrifying biofilter.

    PubMed

    Cui, Bin; Liu, Xiuhong; Yang, Qing; Li, Jianmin; Zhou, Xueyang; Peng, Yongzhen

    2017-08-01

    Partial denitrification was one of most effective ways to provide nitrite for annamox; whereas very limited research has been done to achieve nitrite accumulation in biofilm system. In this study, partial denitrification was studied in a lab-scale denitrifying biofilter (DNBF). The results showed biofilm structure variations caused the differences between nitrate specific reduction rate (NaSRR) and nitrite specific reduction rate (NiSRR), which led to nitrite accumulation in different degree at different biofilm formation phases. Hydrodynamic conditions also significantly influenced biofilm structure, nitrate and nitrite reduction activities. At the filtration velocity of 3.86mh(-1), not only biofilm structure, NaSRR and NiSRR kept relatively stable, but also 60% of nitrite accumulation and no nitrate in the effluent were achieved. Furthermore, Thauera genus bacteria, benefited for nitrite accumulation, became the dominant communities in high nitrite accumulation conditions. The partial denitrification combine with anammox in biofilter have the great potential applied in WWTPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Methane oxidation in a biofilter (Part 1): Development of a mathematical model for designing and optimization.

    PubMed

    Amodeo, Corrado; Masi, Salvatore; Van Hulle, Stijn W H; Zirpoli, Pierfrancesco; Mancini, Ignazio M; Caniani, Donatella

    2015-01-01

    The aim of this work is the evaluation of the efficiency of such a biofilter, through the application of a mathematical model which describes the biological oxidation process. This mathematical model is able to predict the efficiency of the system under varying operating conditions. Literature data have been used in order to build the model. The factors that mostly affect the process and which actually regulate the entire process have been highlighted in this work. Specifically, it was found that temperature, flow and methane concentration are the most important parameters that influence the system. The results obtained from the mathematical model showed also that the biofilter system is simple to implement and manage and allows the achievement of high efficiency of methane oxidation. In the optimal conditions for temperature (between 20-30°C), residence time (between 0.7-0.8 h) and methane molar fraction (between 20-25%) the efficiency of methane oxidation could be around 50%.

  20. Aerated biofilter with seasonally varied operation modes for the production of irrigation water.

    PubMed

    Meda, A; Cornel, P

    2010-01-01

    Water reuse for agricultural irrigation can contribute to the conservation of valuable water resources and opens the possibility to reuse the wastewater's nutrients (N and P) at the same time. As irrigation is usually limited to vegetation periods, effluent requirements for treated wastewater may vary seasonally. A process concept for wastewater treatment with variable operation modes for the seasonal production of nutrient-rich irrigation water and nutrient-poor discharge water is proposed. It is shown that a two-step process consisting of organics removal followed by biological aerated filters (biofilters) for nitrogen removal is a promising combination which allows a flexible and seasonally varied operation with a fast re-start of biological nitrification after shut-down periods. To date, there is no commonly accepted practice amongst operators to take biofilters out of service for periods of time while - at the same time - maintaining biological activity to enable a quick start-up. This paper shows that during shut-down periods the activity drop rate is the smallest if the filter bed is maintained flooded and without aeration; then a very quick re-start is possible.

  1. Pressure drop and gas distribution in compost based biofilters: medium mixing and composition effects.

    PubMed

    Morgan-Sagastume, J M; Revah, S; Noyola, A

    2003-07-01

    The pressure drop and gas distribution in four different filter media for compost biofilters were studied as a function of three superficial loading rates of moist air and by carrying out the filter medium homogenization by mixing. The filter media used were compost, compost with cane bagasse, lava rock and aerobic sludge previously dried to 60% of water content. The pressure drop increased when lava rock and cane bagasse were used as bulking agents. The same trend was observed when water was added to the filter medium. Pressure drop tended to decrease with time as flow channels were formed inthe filter media. Tracer studies were carried out to quantify the gas distribution and the effect of channel formation. For the biofilters submitted to an airflow of 10, 40 and 70 l min(-1), an average normalized time of 0.96, 0.89 and 0.82, respectively were obtained. The results showed that channel formation was increased as the superficial loading rate was also increased. An operational practice that this work proposes and evaluates to improve gas distribution and medium moisture control is to carry out intermittent medium mixing. The medium moisture and void volume achieved under mixing condition were around 50% and 0.40, respectively with an average constant pressure drop of 11, 45 and 78 cm of water m(-1) for air velocities of 75, 300 and 525 m h(-1).

  2. Utilization of macrophyte biofilter in effluent from aquaculture: I. Floating plant.

    PubMed

    Sipaúba-Tavares, L H; Fávero, E G P; Braga, F M S

    2002-11-01

    The objective of this work was to manufacture a low-cost biofilter, made of floating macrophyte (Eichhornia crassipes). Limnological studies were conducted 7 days after the macrophytes were placed in the biofilter, and continued over a period of 30 consecutive days. During rainy and dry seasons, and high production period, samples were taken three times a week. The lowest levels of nitrogen compounds were observed in the July/August period, which corresponded to lower fish production and low supply rattion in the culture ponds. During the experimental period, pH values ranged from acid to alkaline and did not oscillate with higher average values during April/May. Alkalinity and bicarbonate dominance in the medium were directly affected by pH. With respect to associated micro-fauna, among phyto-plankton Chlorophyta was the dominant group and among zooplankton, Rotifera. It is recommended that during production peaks, the aquatic plants should be replaced by small buds every 10 days.

  3. [Analysis of microbial community in a deodorization biofilter by PCR-sSCP method].

    PubMed

    Mi, Wen-Xiu; Xie, Bing; Xu, Ya-Tong

    2008-07-01

    Microbial community of biofilm in a biofiltration was investigated using PCR-SSCP (single strand conformation polymorphism) technique in this paper. The results indicated the removal rate of odor pollutants improved with the acclimation, from 50% to 89%, and the microbial diversity of biofilter decreased at the first month and then increased (diversity index H from 1.6-1.9 to 2.0) while the similarity gradually increased during the operation time. Higher microbial diversity (H = 2.2) in cortex indicated the microorganisms were easily attached to the media compared to the straw (H = 2.0). Dominant bacteria were Bacillus found in the biofilm using SSCP method, and the rate is 33.3%. 44.4% of the total bands represented the uncultured bacteria. These bacteria are widely existed in soil, water and nature environment, they have good acclimatization to environment and played important role in treating odors. The biofilm development was identified by the scanning electron microscopy (SEM), which suggested that the microbial community in biofilter could grow by utilizing pollutants and become rich and stable with running time.

  4. Degradation of p-nitrophenol in a batch biofilter under sequential anaerobic/aerobic environments.

    PubMed

    Melgoza, R M; Buitrón, G

    2001-01-01

    A combined process anaerobic/aerobic in a single reactor was studied, P-nitrophenol (PNP) was used as the model compound. During the anaerobic stage the target compound is modified in such a way that the intermediate product is more readily biodegradable by the aerobic phase. A pilot biofilter was used for the experiment. The biofilter was packed with a volcanic stone (puzolane) to serve as support to the microorganisms and it was inoculated with activated sludge. The microorganisms were acclimated with an initial concentration of 25 mg PNP/l during 75 days (25 cycles). After 230 days of operation, the reaction time of the cycles was reduced to 11.5 h (8 h for the anaerobic phase and 3.5 h for the aerobic one). The PNP was transformed to p-aminophenol (PAP) in the anaerobic phase, with efficiencies near to 100%. A mineralization of 100% of the PAP was found in the oxidative stage. Global efficiencies of PNP mineralization of 98% were obtained. The reaction rates were 16 mg PNP/l-h (PNP uptake), 14 mg PAP/l-h (PAP formation) and 20 mg/l-h (PAP mineralization).

  5. Was leistet ein Sportler? Kraft, Leistung und Energie im Muskel

    NASA Astrophysics Data System (ADS)

    Thaller, Sigrid; Mathelitsch, Leopold

    2006-01-01

    Der Leistungsbegriff ist im Sport weiter gefasst als in der Physik. In beiden Fällen liegt der Fokus jedoch auf einer pro Zeiteinheit erfolgten Energieumsetzung. Allerdings gibt die rein physikalische Leistung nicht immer Auskunft über den Energieumsatz der Muskeln. Die Muskelkraft hängt von der Kontraktionsgeschwindigkeit des Muskels ab. Ein Muskel verhält sich also anders als eine Feder. Für den Hochleistungssport müssen die Energieumsätze der Muskeln durch spezielle Trainings- und Nahrungsprogramme optimiert werden.

  6. Economical assessment of the design, construction and operation of open-bed biofilters for waste gas treatment.

    PubMed

    Prado, O J; Gabriel, D; Lafuente, J

    2009-06-01

    A protocol was developed with the purpose of assessing the main costs implied in the set-up, operation and maintenance of a waste gas-treating conventional biofilter. The main operating parameters considered in the protocol were the empty bed residence time and the gas flow rate. A wide variety of investment and operating costs were considered. In order to check its reliability, the protocol was applied to a number of scenarios, with biofilter volumes ranging from 8.3 to 4000 m(3). Results show that total annualized costs were between 20,000 and 220,000 euro/year and directly dependent, among other factors, on the size of the system. Total investment and operating costs for average-size compost biofilters were around 60,000 euro and 20,000 euro/year, respectively, which are concordant with actual costs. Also, a sensitivity analysis was performed in order to assess the relative influence of a series of selected costs. Results prove that operating costs are those that influence the total annual costs to a higher extent. Also, packing material replacement costs contribute significantly to the total yearly costs in biofilters with a volume higher than 800 m(3). Among operating costs, the electricity consumption is the main influencing factor in biofilters with a gas flow rate above 50,000 m(3)/h, while labor costs are critical at lower gas flow rates. In addition, the use of a variety of packing materials commonly employed in biofiltration was assessed. According to the results obtained, special attention should be paid to the packing material selected, as it is the main parameter influencing the medium replacement costs, and one of the main factors affecting investment costs.

  7. Ammonia biofiltration and nitrous oxide generation during the start-up of gas-phase compost biofilters

    NASA Astrophysics Data System (ADS)

    Maia, Guilherme D. N.; Day V, George B.; Gates, Richard S.; Taraba, Joseph L.

    2012-01-01

    Gas-Phase Biofiltration technology is widely utilized for treating ammonia gas (NH 3) with one of its potential detrimental by-products being nitrous oxide (N 2O), a potent greenhouse gas (100-y radiative forcing 298 times greater than carbon dioxide). The present work was conducted to investigate the relation between NH 3 removal during biofiltration and N 2O generation as a product of incomplete denitrification during the start-up of gas-phase compost biofilters. Four laboratory scale tubular biofilters in up flow mode (20 s residence-time) were studied for 21 days: 3 replicates were subjected to 16 ppm v (0.78 g m -2 h -1) of NH 3 and a statistical control not subjected to NH 3. Ammonia concentration differences between biofilter inlet (Bottom = 16 ppm v) and outlet (Top) and N 2O concentration differences between biofilter outlet (Top) and biofilter inlet (background concentrations at the bottom) were used to determine the extent of the correlation between NH 3 removal and N 2O generation. Correlations with CH 4 and CO 2 were also reported. The high Spearman correlation coefficients for the three replicates ( ρ = -0.845, -0.820, and -0.841, with P ≤ 0.0001 for replications A, B and C, respectively) suggested that availability of nitrate/nitrite owing to NH 3 nitrification favored conditions for N 2O generation as a sub-product of denitrification. The statistical control received no NH 3 inputs and did not generate N 2O. Therefore, the results indicated that the process of NH 3 removal was a trigger for N 2O production. Carbon dioxide and N 2O were moderately correlated. Methane and N 2O were weakly correlated and only for replicate C. No significant correlation was found for the Statistical Control between N 2O and CH 4.

  8. Mol-Gastronomie Käsefondue: eine kolloidale Schmelze

    NASA Astrophysics Data System (ADS)

    Vilgis, Thomas A.

    2004-11-01

    An Weihnachten oder zum Jahreswechsel kommt gern das Fonduegeschirr zum Einsatz, weil sich damit viele hungrige Gäste unterhaltsam sättigen lassen. Käsefondues sind allerdings eine physikalisch anspruchsvolle Angelegenheit. Die Kunst besteht darin, die viskoelastische Käseschmelze während des Genusses homogen zu halten.

  9. A Progenitor Candidate for SN 2017ein in NGC 3938

    NASA Astrophysics Data System (ADS)

    Van Dyk, Schuyler D.; Filippenko, Alexei V.; Fox, Ori D.; Kelly, Patrick L.; Milisavljevic, Dan; Smith, Nathan

    2017-06-01

    We report the identification of a progenitor candidate for the Type Ic SN 2017ein in NGC 3938 (ATel #10434, #10481) in archival Hubble Space Telescope (HST) images obtained with the Wide Field Planetary Camera 2 (WFPC2) on 2007 December 11 UT in bands F555W and F814W, as part of program GO-10877 (PI: A.V. Filippenko).

  10. Bacterial community in the biofilm of granular activated carbon (GAC) PreBiofilter in bench-scale pilot plants for surface water pretreatment.

    PubMed

    Wu, Tiehang; Fu, George Yuzhu; Sabula, Michael; Brown, Tommy

    2014-12-01

    Biofilters of granular activated carbon (GAC) are responsible for the removal of organic matters in drinking water treatments. PreBiofilters, which operate as the first unit in a surface water treatment train, are a cost-effective pretreatment for conventional surface water treatment and provide more consistent downstream water quality. This study investigated bacterial communities from the samples of raw surface water, biofilm on the PreBiofilter, and filtrates for surface water pretreatment. A bench-scale pilot plant of PreBiofilter was constructed to pretreat surface water from the Canoochee River, GA, USA. PreBiofilter exhibited a significant reduction of total organic carbon and dissolved organic carbon. The evenness and Shannon diversity of bacterial operational taxonomic units (OTUs) were significantly higher on the biofilm of PreBiofilter than in raw water and filtrates. Similar bacteria communities were observed in the raw water and filtrates using relative abundance of bacterial OTUs. However, the bacterial communities in the filtrates became relatively similar to those in the biofilm using presence/absence of bacterial OTUs. GAC biofilm or raw water and filtrates greatly contributed to the abundance of bacteria; whereas, bacteria sheared from colonized biofilm and entered filtrates. Evenly distributed, diverse and unique bacteria in the biofilm played an important role to remove organic matters from surface water for conventional surface water pretreatment.

  11. Moisture effects on greenhouse gases generation in nitrifying gas-phase compost biofilters.

    PubMed

    Maia, Guilherme D N; Day, George B; Gates, Richard S; Taraba, Joseph L; Coyne, Mark S

    2012-06-01

    Gas-phase compost biofilters are extensively used in concentrated animal feeding operations to remove odors and, in some cases, ammonia from air sources. The expected biochemical pathway for these predominantly aerobic systems is nitrification. However, non-uniform media with low oxygen levels can shift biofilter microbial pathways to denitrification, a source of greenhouse gases. Several factors contribute to the formation of anoxic/anaerobic zones: media aging, media and particle structure, air velocity distribution, compaction, biofilm thickness, and moisture content (MC) distribution. The present work studies the effects of media moisture conditions on ammonia (NH(3)) removal and greenhouse gas generation (nitrous oxide, N(2)O and methane, CH(4)) for gas-phase compost biofilters subject to a 100-day controlled drying process. Continuous recordings were made for the three gases and water vapor (2.21-h sampling cycle, each cycle consisted of three gas species, and water vapor, for a total of 10,050 data points). Media moisture conditions were classified into three corresponding media drying rate (DR) stages: Constant DR (wetter media), falling DR, and stable-dry system. The first-half of the constant DR period (0-750 h; MC=65-52%, w.b.) facilitated high NH(3) removal rates, but higher N(2)O generation and no CH(4) generation. At the drier stages of the constant DR (750-950 h; MC=52-48%, w.b.) NH(3) removal remained high but N(2)O net generation decreased to near zero. In the falling DR stage (1200-1480 h; MC=44-13%) N(2)O generation decreased, CH(4) increased, and NH(3) was no longer removed. No ammonia removal or greenhouse gas generation was observed in the stable-dry system (1500-2500 h; MC=13%). These results indicate that media should remain toward the drier region of the constant DR (in close proximity to the falling DR stage; MC=50%, approx.), to maintain high levels of NH(3) removal, reduced levels of N(2)O generation, and nullify levels of CH(4

  12. Comparison of NOx Removal Efficiencies in Compost Based Biofilters Using Four Different Compost Sources

    SciTech Connect

    Lacey, Jeffrey Alan; Lee, Brady Douglas; Apel, William Arnold

    2001-06-01

    In 1998, 3.6 trillion kilowatt-hours of electricity were generated in the United States. Over half of this was from coal-fired power plants, resulting in more than 8.3 million tons of nitrogen oxide (NOx) compounds being released into the environment. Over 95% of the NOx compounds produced during coal combustion are in the form of nitric oxide (NO). NOx emission regulations are becoming increasingly stringent, leading to the need for new, cost effective NOx treatment technologies. Biofiltration is such a technology. NO removal efficiencies were compared in compost based biofilters using four different composts. In previous experiments, removal efficiencies were typically highest at the beginning of the experiment, and decreased as the experiments proceeded. This work tested different types of compost in an effort to find a compost that could maintain NO removal efficiencies comparable to those seen early in the previous experiments. One of the composts was wood based with manure, two were wood based with high nitrogen content sludge, and one was dairy compost. The wood based with manure and one of the wood based with sludge composts were taken directly from an active compost pile while the other two composts were received in retail packaging which had been out of active piles for an indeterminate amount of time. A high temperature (55-60°C) off-gas stream was treated in biofilters operated under denitrifying conditions. Biofilters were operated at an empty bed residence time of 13 seconds with target inlet NO concentrations of 500 ppmv. Lactate was the carbon and energy source. Compost was sampled at 10-day intervals to determine aerobic and anaerobic microbial densities. Compost was mixed at a 1:1 ratio with lava rock and calcite was added at 100g/kg of compost. In each compost tested, the highest removal efficiencies occurred within the first 10 days of the experiment. The wood based with manure peaked at day 3 (77.14%), the dairy compost at day 1 (80.74%), the

  13. BIOFILTER AS A FUNCTIONAL ANNOTATION PIPELINE FOR COMMON AND RARE COPY NUMBER BURDEN

    PubMed Central

    KIM, DOKYOON; LUCAS, ANASTASIA; GLESSNER, JOSEPH; VERMA, SHEFALI S.; BRADFORD, YUKI; LI, RUOWANG; FRASE, ALEX T.; HAKONARSON, HAKON; PEISSIG, PEGGY; BRILLIANT, MURRAY; RITCHIE, MARYLYN D.

    2015-01-01

    Recent studies on copy number variation (CNV) have suggested that an increasing burden of CNVs is associated with susceptibility or resistance to disease. A large number of genes or genomic loci contribute to complex diseases such as autism. Thus, total genomic copy number burden, as an accumulation of copy number change, is a meaningful measure of genomic instability to identify the association between global genetic effects and phenotypes of interest. However, no systematic annotation pipeline has been developed to interpret biological meaning based on the accumulation of copy number change across the genome associated with a phenotype of interest. In this study, we develop a comprehensive and systematic pipeline for annotating copy number variants into genes/genomic regions and subsequently pathways and other gene groups using Biofilter – a bioinformatics tool that aggregates over a dozen publicly available databases of prior biological knowledge. Next we conduct enrichment tests of biologically defined groupings of CNVs including genes, pathways, Gene Ontology, or protein families. We applied the proposed pipeline to a CNV dataset from the Marshfield Clinic Personalized Medicine Research Project (PMRP) in a quantitative trait phenotype derived from the electronic health record – total cholesterol. We identified several significant pathways such as toll-like receptor signaling pathway and hepatitis C pathway, gene ontologies (GOs) of nucleoside triphosphatase activity (NTPase) and response to virus, and protein families such as cell morphogenesis that are associated with the total cholesterol phenotype based on CNV profiles (permutation p-value < 0.01). Based on the copy number burden analysis, it follows that the more and larger the copy number changes, the more likely that one or more target genes that influence disease risk and phenotypic severity will be affected. Thus, our study suggests the proposed enrichment pipeline could improve the

  14. BIOFILTER AS A FUNCTIONAL ANNOTATION PIPELINE FOR COMMON AND RARE COPY NUMBER BURDEN.

    PubMed

    Kim, Dokyoon; Lucas, Anastasia; Glessner, Joseph; Verma, Shefali S; Bradford, Yuki; Li, Ruowang; Frase, Alex T; Hakonarson, Hakon; Peissig, Peggy; Brilliant, Murray; Ritchie, Marylyn D

    2016-01-01

    Recent studies on copy number variation (CNV) have suggested that an increasing burden of CNVs is associated with susceptibility or resistance to disease. A large number of genes or genomic loci contribute to complex diseases such as autism. Thus, total genomic copy number burden, as an accumulation of copy number change, is a meaningful measure of genomic instability to identify the association between global genetic effects and phenotypes of interest. However, no systematic annotation pipeline has been developed to interpret biological meaning based on the accumulation of copy number change across the genome associated with a phenotype of interest. In this study, we develop a comprehensive and systematic pipeline for annotating copy number variants into genes/genomic regions and subsequently pathways and other gene groups using Biofilter - a bioinformatics tool that aggregates over a dozen publicly available databases of prior biological knowledge. Next we conduct enrichment tests of biologically defined groupings of CNVs including genes, pathways, Gene Ontology, or protein families. We applied the proposed pipeline to a CNV dataset from the Marshfield Clinic Personalized Medicine Research Project (PMRP) in a quantitative trait phenotype derived from the electronic health record - total cholesterol. We identified several significant pathways such as toll-like receptor signaling pathway and hepatitis C pathway, gene ontologies (GOs) of nucleoside triphosphatase activity (NTPase) and response to virus, and protein families such as cell morphogenesis that are associated with the total cholesterol phenotype based on CNV profiles (permutation p-value < 0.01). Based on the copy number burden analysis, it follows that the more and larger the copy number changes, the more likely that one or more target genes that influence disease risk and phenotypic severity will be affected. Thus, our study suggests the proposed enrichment pipeline could improve the interpretability of

  15. Biofiltration of xylene using wood charcoal as the biofilter media under transient and high loading conditions.

    PubMed

    Singh, Kiran; Giri, B S; Sahi, Amrita; Geed, S R; Kureel, M K; Singh, Sanjay; Dubey, S K; Rai, B N; Kumar, Surendra; Upadhyay, S N; Singh, R S

    2017-10-01

    The main objective of this study was to evaluate the performance of wood charcoal as biofilter media under transient and high loading condition. Biofiltration of xylene was investigated for 150days in a laboratory scale unit packed with wood charcoal and inoculated with mixed microbial culture at the xylene loading rates ranged from 12 to 553gm(-3)h(-1). The kinetic analysis of the xylene revealed absence of substrate inhibition and possibility of achieving higher elimination under optimum condition. The pH, temperature, pressure drop and CO2 production rate were regularly monitored during the experiments. Throughout experimental period, the removal efficiency (RE) was found to be in the range of 65-98.7% and the maximum elimination capacity (EC) was 405.7gm(-3)h(-1). Molecular characterization results show Bacillus sp. as dominating microbial group in the biofilm. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Degradation and characteristic changes of organic matter in sewage sludge using Vermi-biofilter system.

    PubMed

    Zhong, Hui-Yuan; Wang, Hao; Liu, Xiao; Liu, Chang; Liu, Guan-Yi; Tian, Yang; Feng, Xuan-Ming; Chen, Yan-Hua

    2017-08-01

    Vermi-biofilter (VF) System could be an efficient sludge treatment unit in regard of rates and extents of total chemical oxygen demand (TCOD) removal, particularly the first 10 days earthworm-treated. This study characterized the organic matter in sludge before and after VF system treatment, with or without earthworm stage. The 60 days earthworm-treated VF system reached a TCOD removal of 10,450 mg/L, bulk DOC removal of 89.5 mg/L, and earthworm density increase from 32 g/L to 43 g/L in sludge EBOM in 60 days of VF system operation. The aromatic proteins, soluble microbial byproduct-like fluorescent compounds and carboxylic components, aliphatic components (C-H related), hydrocarbon and carbohydrate materials were identified to be principally increased by 10 days earthworm-treated and then degradation in the nest days under VF system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Physical characterisation of the sludge produced in a sequencing batch biofilter granular reactor.

    PubMed

    Lotito, Adriana Maria; Di Iaconi, Claudio; Lotito, Vincenzo

    2012-10-15

    Sequencing batch biofilter granular reactor (SBBGR) is a recently developed biological wastewater treatment technology characterised by a very low sludge production, among other numerous advantages. Even if costs for sludge treatment and disposal are mainly dependent on the amount of sludge produced, sludge properties, especially those linked to solid-liquid separation, play a key role as well. In fact, such properties deeply influence the type of treatments sludge has to undergo before disposal and the final achievable solids concentration, strongly affecting treatment and disposal costs. As sludge from SBBGR is a special mixture of biofilm and aerobic granules, no information is available so far on its treatability. This study addresses the characterisation of the sludge produced from SBBGR in terms of some physical properties (settling properties, dewaterability, rheology). The results show that such sludge is characterised by good settling and dewatering properties, adding a new advantage for the full-scale application of SBBGR technology.

  18. Mathematical modeling of biofiltration in activated pine-bark charge of a biofilter.

    PubMed

    Vaiskunaite, Rasa; Baltrenas, Pranas; Spakauskas, Valdas

    2005-09-01

    AIM, SCOPE AND BACKGROUND: Human economic activities cause emissions of various pollutants of an organic nature: butanol, butyl acetate, methanol, formaldehyde, phenol, benzene, toluene, xylene, etc. These compounds are emitted to atmosphere by various enterprises of food, chemistry, wood processing industries, from transportation means, agricultural enterprises, etc. Therefore, when purifying air from these pollutants, it is necessary to apply efficient and inexpensive air purification methods. In this dimension, the biological air purification is chosen from all possible air cleaning methods. An experimental biofilter with the activated charge of pine bark was developed at the Department of Environment Protection of the Vilnius Gediminas Technical University. In the course of the experimental investigation, it was determined that this air purification method is efficient. Filter efficiency, when purifying air of volatile organic compounds (butanol, butyl acetate and xylene), to a great extent, depending on the nature and concentrations (up to 100 mg/m3) of pollutants injected, might go up to 70-98%. The mathematical model of the biofilter was developed based on the research results and fully taking into consideration physical, chemical, and biological processes going on during its operations. The aim of this article is to determine biodegradation constant alpha, absorption capacity beta, and half empiric expressions of filter efficiency. Knowing this, it is possible to find out the dependence of the filter efficiency on the operational parameters of the filter (i.e. on the concentrations and the height of biocharge of the initial pollutants (butanol, butyl acetate, xylene) fed through it). With the help of mathematical modeling, the biodegradation constants and absorption capability of volatile organic compounds (butanol, butyl acetate, and xylene) fed into the biofilter charged with the activated pine bark and used for the cleaning of volatile organic compounds

  19. Shock loading in biofilters: impact on biodegradation activity distribution and resilience capacity.

    PubMed

    Cabrol, L; Malhautier, L; Poly, F; Lepeuple, A S; Fanlo, J L

    2009-01-01

    A synthetic contaminated gas was generated, representative of gaseous emissions from sludge composting. It was composed of six volatile organic compounds (aldehyde, ketones, esters, sulphur compound) in an ammoniacal matrix. The gaseous stream was purified by biofiltration, in pilot scale biofilters filled with pine bark woodchips as organic carrier for biomass colonization. After reaching a constant high efficiency, with complete removal, the system was disturbed by transient loading shocks. The impact of perturbations was assessed by both performance evaluation (i.e. contaminant removal) and microbial behaviour. The microbial community was analysed in terms of density. The resilience of functional component following a perturbation was evaluated. This work highlighted the longitudinal distribution of both biodegradation activities and biomass density.

  20. The use of biofilters to improve indoor air quality: the removal of toluene, TCE, and formaldehyde.

    PubMed

    Darlington, A; Dixon, M A; Pilger, C

    1998-01-01

    A biofilter composed of a scrubber, a hydroponic planting system, and an aquatic system with green plants as a base maintained air quality within part of a modern office building. The scrubber was composed of five parallel fiberglass modules with external faces of porous lava rock. The face, largely covered with mosses, was wetted by recirculating water. Air was drawn through the scrubber and the immediately adjacent hydroponic region by a dedicated air handling system. The system was challenged for 4 weeks with three common indoor organic pollutants and removed significant amounts of all compounds. A single pass through the scrubber removed 10% of the trichloroethylene and 50% of the toluene. A single pass lowered formaldehyde air concentrations to 13 micrograms m-3 irrespective of influent levels (ranging between 30 and 90 micrograms m-3). The aquatic system accumulated trichloroethylene but neither toluene nor formaldehyde, suggesting the rapid breakdown of these materials. The botanical components removed some pollutants.

  1. [Potential of nitrification and denitrification in water purification system with hydroponic bio-filter method].

    PubMed

    Li, Xian-ing; Lu, Xi-wu; Song, Hai-liang; Osamu, Nishimura; Yuhei, Inamori

    2005-03-01

    The potential of nitrification and denitrification of sediment and the density of ammonium-oxidizing bacteria and nitrite-oxidizing bacteria in sediment in water quality purifying system with hydroponic bio-filter method (HBFM) were measured. The variation of nitrification and denitrification potential of the sediment along the stream way was quantitatively studied. The results show that among the sediments from front, middle and retral part of the stream way, the sediment from middle part reached a maximum nitrification potential . nitrification potential of 4.76 x 10(-6) g/(g x h), while the sediment from front part reached a maximum denitrification potential of 8 .1 x 10(-7) g/(g x h). The distribution of nitrification potential accords with the ammonium-oxidizing bacteria density. The key for improving nitrogen removal efficiency of HBFM system consists in changing nitrification & denitrification region distributing and accordingly enhances denitrification process.

  2. Kinetics studies on the removal of Methyl ethyl ketone using cornstack based biofilter.

    PubMed

    Ashokkumar, S; Nair, Aprana S; Saravanan, V; Rajasimman, M; Rajamohan, N

    2016-12-01

    The performance of cornstack based biofilter inoculated with a mixed culture was evaluated for gas phase MEK removal under various operating conditions. Experiments were carried out at different flow rates (0.03-0.12m(3)h(-1)) and various initial concentrations (0.2-1.2g(-3)). A maximum elimination capacity (EC) of 35g(-3)h(-1) was achieved at an inlet loading rate of 60g(-3)h(-1) with a removal efficiency of 95%. High elimination capacity reached with this system could have been due to the dominant presence of filamentous fungi among others. The experimental results were compared with the values obtained from the Ottengraf-van den Oever model for zero-order diffusion-controlled region. The critical inlet concentration, critical inlet load and biofilm thickness were estimated using the model predictions. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Assessing the Efficacy of the Aerobic Methanotrophic Biofilter in Methane Hydrate Environments

    SciTech Connect

    Valentine, David

    2012-09-30

    In October 2008 the University of California at Santa Barbara (UCSB) initiated investigations of water column methane oxidation in methane hydrate environments, through a project funded by the National Energy Technology Laboratory (NETL) entitled: assessing the efficacy of the aerobic methanotrophic biofilter in methane hydrate environments. This Final Report describes the scientific advances and discoveries made under this award as well as the importance of these discoveries in the broader context of the research area. Benthic microbial mats inhabit the sea floor in areas where reduced chemicals such as sulfide reach the more oxidizing water that overlies the sediment. We set out to investigate the role that methanotrophs play in such mats at locations where methane reaches the sea floor along with sulfide. Mats were sampled from several seep environments and multiple sets were grown in-situ at a hydrocarbon seep in the Santa Barbara Basin. Mats grown in-situ were returned to the laboratory and used to perform stable isotope probing experiments in which they were treated with 13C-enriched methane. The microbial community was analyzed, demonstrating that three or more microbial groups became enriched in methane?s carbon: methanotrophs that presumably utilize methane directly, methylotrophs that presumably consume methanol excreted by the methanotrophs, and sulfide oxidizers that presumably consume carbon dioxide released by the methanotrophs and methylotrophs. Methanotrophs reached high relative abundance in mats grown on methane, but other bacterial processes include sulfide oxidation appeared to dominate mats, indicating that methanotrophy is not a dominant process in sustaining these benthic mats, but rather a secondary function modulated by methane availability. Methane that escapes the sediment in the deep ocean typically dissolved into the overlying water where it is available to methanotrophic bacteria. We set out to better understand the efficacy of this

  4. Effect of shutdown on styrene removal in a biofilter inoculated with Pseudomonas sp. SR-5.

    PubMed

    Jang, Jong Hee; Hirai, Mitsuyo; Shoda, Makoto

    2006-02-28

    Styrene gas removal was carried out in a biofilter inoculated with a styrene-degrading Pseudomonas sp. SR-5 using a mixed packing material of peat and ceramic under the non-sterile condition. More than 86% removal efficiency was obtained at styrene load of 5-93 g m(-3) h(-1) for 62 days operation period and 78% carbon of removed styrene was converted to CO2. Thereafter, three kinds of styrene shutdown experiments were conducted: (i) air and mineral medium were supplied for 4 days, (ii) complete shutdown, namely no styrene, air and moisture supply was conducted for 3 days, and (iii) only air was supplied for 11 days. When styrene gas was re-supplied after (i) and (iii) shutdown experiments, styrene removal efficiency rapidly recovered, but after (ii) shutdown, recovery of styrene removal was significantly delayed. Supply of air during shutdown period was found to be enough to resume microbial activity to degrade styrene.

  5. Biofiltration of 1,1,1-trichloroethane by a trickle-bed air biofilter.

    PubMed

    Lu, Chungsying; Chang, Kwotsair

    2003-09-01

    The performance of a trickle-bed air biofilter (TBAB) in the removal of 1,1,1-trichloroethane (TCLE) was evaluated in concentrations varying from 0.025 to 0.049 g/m3 and at empty-bed residence time (EBRT) varying from 20 to 90 s. Nearly complete TCLE removal could be achieved for influent carbon loading between 0.98 and 5.88 g/m3 h. The TBAB appeared efficient for controlling TCLE emission under low-carbon-loading conditions. Carbon recoveries higher than 95% were achieved, demonstrating the accuracy of results. The carbon mass rate of the liquid effluent was approximately two orders of magnitude less than that of the effluent CO2, indicating that dissolved TCLE and its derivatives in leachate were present in negligible amounts in the TBAB.

  6. Methodologies for Pre-Validation of Biofilters and Wetlands for Stormwater Treatment

    PubMed Central

    Zhang, Kefeng; Randelovic, Anja; Aguiar, Larissa M.; Page, Declan; McCarthy, David T.; Deletic, Ana

    2015-01-01

    Background Water Sensitive Urban Design (WSUD) systems are frequently used as part of a stormwater harvesting treatment trains (e.g. biofilters (bio-retentions and rain-gardens) and wetlands). However, validation frameworks for such systems do not exist, limiting their adoption for end-uses such as drinking water. The first stage in the validation framework is pre-validation, which prepares information for further validation monitoring. Objectives A pre-validation roadmap, consisting of five steps, is suggested in this paper. Detailed methods for investigating target micropollutants in stormwater, and determining challenge conditions for biofilters and wetlands, are provided. Methods A literature review was undertaken to identify and quantify micropollutants in stormwater. MUSIC V5.1 was utilized to simulate the behaviour of the systems based on 30-year rainfall data in three distinct climate zones; outputs were evaluated to identify the threshold of operational variables, including length of dry periods (LDPs) and volume of water treated per event. Results The paper highlights that a number of micropollutants were found in stormwater at levels above various worldwide drinking water guidelines (eight pesticides, benzene, benzo(a)pyrene, pentachlorophenol, di-(2-ethylhexyl)-phthalate and a total of polychlorinated biphenyls). The 95th percentile LDPs was exponentially related to system design area while the 5th percentile length of dry periods remained within short durations (i.e. 2–8 hours). 95th percentile volume of water treated per event was exponentially related to system design area as a percentage of an impervious catchment area. Conclusions The out-comings of this study show that pre-validation could be completed through a roadmap consisting of a series of steps; this will help in the validation of stormwater treatment systems. PMID:25955688

  7. Adsorption and abiotic oxidation of arsenic by aged biofilter media: equilibrium and kinetics.

    PubMed

    Sahabi, Danladi Mahuta; Takeda, Minoru; Suzuki, Ichiro; Koizumi, Jun-ichi

    2009-09-15

    Removal of arsenic from groundwater by biological adsorptive filtration depends largely on its interaction with biogenic iron and manganese oxides surfaces. In the present study we investigated the arsenic adsorption and abiotic oxidation capacities of an aged biofilter medium (BM2) collected from a long time established groundwater treatment plant for removal of iron and manganese by biological filtration. Batch oxidation/adsorption kinetic experiments indicated that BM2 can easily oxidize As(III) to As(V) with the rate of oxidation less affected by pH-variations from 4 to 8.5. The adsorption capacity of the biofilter medium for the produced or added As(V), however, depends strongly on the pH of the solution. The kinetics results have shown that As(III) sorption followed pseudo-second order kinetics, whereas the sorption of As(V) was best described by the intra-particle diffusion model, indicating that adsorptions of As(III) and As(V) onto BM2 were governed by different mechanisms. Adsorption isotherms at 25 degrees C were measured for a range of arsenite and arsenate initial concentrations of 0.67-20 micromol/L and the pH range from 4 to 9. Adsorption maxima were highest at pH 4 and decrease steadily as the pH increases. The equilibrium data for both As(III) and As(V) fitted very well to the Freundlich and Sips isotherm equations and, in most cases, the two isotherms overlapped with the same correlation coefficients, indicating sorption to be multilayer on the heterogeneous surface of BM2. The implication of the data for arsenic removal from water by biological filtration has been discussed.

  8. A method for enhanced control of biomass activity and distribution in biofilters

    SciTech Connect

    Song, J.H.; Kinney, K.A.

    1999-07-01

    Long-term performance of vapor-phase bioreactors can be unreliable because of uneven distribution of biomass and microbial activity throughout the bioreactors. One method to improve biomass distribution and maintain high removal efficiencies for continuous long-term use is to operate the bioreactor in a directionally-switching (DS) mode, in which the contaminant inlet is periodically switched between the top and bottom of the reactor column. The objective of this study was to evaluate the effect of DS operation on biomass distribution and activity. Two identical lab-scale biofilters were operated for 96 days at an inlet toluene concentration of 200 ppmv and an EBCT of 1 minute. One bioreactor operated in a unidirectional (UD) mode where the air stream was continuously fed to the bottom of the reactor, and the other operated in a DS mode in which the direction of the air stream through the bioreactor was reversed every 3 days. After an initial acclimation period, toluene removal efficiencies of over 99.9% were achieved in both bioreactors for over 40 days of operation. However, toluene removal efficiencies in the UD biofilter declined after 70 days and the pressure drop across the reactor increased quickly, whereas the DS reactor maintained relatively stable operation throughout the same period. The biomass distribution determined by volatile solids and plate counts indicates that the biomass was well distributed in the DS reactor, while excess biomass accumulated in the inlet section of the UD bioreactor. INT (iodonitrotetrazolium chloride) formazan assays were performed to estimate the biomass activity along the length of both bioreactors. These results reveal that biomass activity was more evenly distributed and sustained in the DS bioreactor, but in the UD bioreactor most of the bioactivity was confined to the front half of the bed.

  9. Experiments and three phase modelling of a biofilter for the removal of toluene and trichloroethylene.

    PubMed

    Das, Chhaya; Chowdhury, Ranjana; Bhattacharya, Pinaki

    2011-05-01

    Volatile organic compounds, namely, toluene, trichloroethylene, styrene, etc., disposed off by electronics and polymer industries, are very harmful. The treatment of VOC laden air through biochemical route is one of the potential options for reduction of their concentration in parts per million or parts per billion level. Under the present investigation, a 0.05-m diameter and 0.58-m high trickle bed biofilter has been studied for the removal of VOCs namely toluene and trichloroethylene from a simulated air-VOC mixture using pure strain of Pseudomonas putida (NCIM2650) in immobilized form. Inlet concentrations of VOCs have been varied in two ranges, the lower being 0.20-2.00 g/m(3) and higher being 10-20 g/m(3), respectively. The Monod type rate kinetics of removal of VOCs has been determined. A three-phase deterministic mathematical model has been developed taking the simultaneous reaction kinetics and interphase (gas to liquid to biofilm) mass transfer rate of VOCs into consideration. Experimentally determined kinetic parameters and mass transfer coefficients calculated using standard correlations have been used. Concentrations have been simulated for all the three phases. Simulated results based on the model have been compared with the experimental ones for both gas and liquid phases satisfactorily. The mathematical model validated through the successful comparison with experimental data may be utilized for the prediction of performance of biofilters undergoing removal of different VOCs in any further investigation and may be utilized for the scale-up of the system to industrial scale.

  10. Methodologies for pre-validation of biofilters and wetlands for stormwater treatment.

    PubMed

    Zhang, Kefeng; Randelovic, Anja; Aguiar, Larissa M; Page, Declan; McCarthy, David T; Deletic, Ana

    2015-01-01

    Water Sensitive Urban Design (WSUD) systems are frequently used as part of a stormwater harvesting treatment trains (e.g. biofilters (bio-retentions and rain-gardens) and wetlands). However, validation frameworks for such systems do not exist, limiting their adoption for end-uses such as drinking water. The first stage in the validation framework is pre-validation, which prepares information for further validation monitoring. A pre-validation roadmap, consisting of five steps, is suggested in this paper. Detailed methods for investigating target micropollutants in stormwater, and determining challenge conditions for biofilters and wetlands, are provided. A literature review was undertaken to identify and quantify micropollutants in stormwater. MUSIC V5.1 was utilized to simulate the behaviour of the systems based on 30-year rainfall data in three distinct climate zones; outputs were evaluated to identify the threshold of operational variables, including length of dry periods (LDPs) and volume of water treated per event. The paper highlights that a number of micropollutants were found in stormwater at levels above various worldwide drinking water guidelines (eight pesticides, benzene, benzo(a)pyrene, pentachlorophenol, di-(2-ethylhexyl)-phthalate and a total of polychlorinated biphenyls). The 95th percentile LDPs was exponentially related to system design area while the 5th percentile length of dry periods remained within short durations (i.e. 2-8 hours). 95th percentile volume of water treated per event was exponentially related to system design area as a percentage of an impervious catchment area. The out-comings of this study show that pre-validation could be completed through a roadmap consisting of a series of steps; this will help in the validation of stormwater treatment systems.

  11. 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.

  12. Start-up, performance and optimization of a compost biofilter treating gas-phase mixture of benzene and toluene.

    PubMed

    Rene, Eldon R; Kar, Saurajyoti; Krishnan, Jagannathan; Pakshirajan, K; López, M Estefanía; Murthy, D V S; Swaminathan, T

    2015-08-01

    The performance of a compost biofilter inoculated with mixed microbial consortium was optimized for treating a gas-phase mixture of benzene and toluene. The biofilter was acclimated to these VOCs for a period of ∼18d. The effects of concentration and flow rate on the removal efficiency (RE) and elimination capacity (EC) were investigated by varying the inlet concentration of benzene (0.12-0.95g/m(3)), toluene (0.14-1.48g/m(3)) and gas-flow rate (0.024-0.072m(3)/h). At comparable loading rates, benzene removal in the mixture was reduced in the range of 6.6-41% in comparison with the individual benzene degradation. Toluene removal in mixture was even more affected as observed from the reductions in REs, ranging from 18.4% to 76%. The results were statistically interpreted by performing an analysis of variance (ANOVA) to elucidate the main and interaction effects.

  13. Autotrophic denitrification by nitrate-dependent Fe(II) oxidation in a continuous up-flow biofilter.

    PubMed

    Zhou, Jun; Wang, Hongyu; Yang, Kai; Ji, Bin; Chen, Dan; Zhang, Huining; Sun, Yuchong; Tian, Jun

    2016-02-01

    A continuous-upflow biofilter packed with sponge iron was constructed for nitrate removal under an anaerobic atmosphere. Microbacterium sp. W5, a nitrate reducing and Fe(II) oxidizing strain, was added to the biofilter as an inoculum. The best results were achieved when NO3 (-)-N concentration was 30 mg/L and Fe(2+) was 800 mg/L. Nitrite in influent would inhibit nitrate removal and aqueous Fe(2+) resulted in encrustation. Fe(II)EDTA would prevent cells from encrustation and the maximum nitrogen removal efficiency was about 90 % with Fe(II)EDTA level of 1100 mg/L. Nitrate reduction followed first-order reaction kinetics. Characteristics of biofilms were analyzed by X-ray fluorescence spectroscopy.

  14. Silica sol-gel encapsulated methylotrophic yeast as filling of biofilters for the removal of methanol from industrial wastewater.

    PubMed

    Kamanina, Olga A; Lavrova, Daria G; Arlyapov, Viacheslav A; Alferov, Valeriy A; Ponamoreva, Olga N

    2016-10-01

    This research suggests the use of new hybrid biomaterials based on methylotrophic yeast cells covered by an alkyl-modified silica shell as biocatalysts. The hybrid biomaterials are produced by sol-gel chemistry from silane precursors. The shell protects microbial cells from harmful effects of acidic environment. Potential use of the hybrid biomaterials based on methylotrophic yeast Ogataea polymorpha VKM Y-2559 encapsulated into alkyl-modified silica matrix for biofilters is represented for the first time. Organo-silica shells covering yeast cells effectively protect them from exposure to harmful factors, including extreme values of pH. The biofilter based on the organic silica matrix encapsulated in the methylotrophic yeast Ogataea polymorpha BKM Y-2559 has an oxidizing power of 3 times more than the capacity of the aeration tanks used at the chemical plants during methyl alcohol production. This may lead to the development of new and effective industrial wastewater treatment technologies. Copyright © 2016. Published by Elsevier Inc.

  15. Resistance and resilience of removal efficiency and bacterial community structure of gas biofilters exposed to repeated shock loads.

    PubMed

    Cabrol, Léa; Malhautier, Luc; Poly, Franck; Roux, Xavier Le; Lepeuple, Anne-Sophie; Fanlo, Jean-Louis

    2012-11-01

    Since full-scale biofilters are often operated under fluctuating conditions, it is critical to understand their response to transient states. Four pilot-scale biofilters treating a composting gas mixture and undergoing repeated substrate pulses of increasing intensity were studied. A systematic approach was proposed to quantify the resistance and resilience capacity of their removal efficiency, which enabled to distinguish between recalcitrant (ammonia, DMDS, ketones) and easily degradable (esters and aldehyde) compounds. The threshold of disturbing shock intensity and the influence of disturbance history depended on the contaminant considered. The spatial and temporal distribution of the bacterial community structure in response to the perturbation regime was analysed by Denaturing Gradient Gel Electrophoresis (DGGE). Even if the substrate-pulses acted as a driving force for some community characteristics (community stratification), the structure-function relationships were trickier to evidence: the distributions of resistance and composition were only partially coupled, with contradictory results depending on the contaminant considered.

  16. Water transformation in the media of biofilters controlled by Rhodococcus fascians in treating an ethyl acetate-contaminated airstream.

    PubMed

    Hwang, Sz-Chwun John; Wu, Shang-Ju; Lee, Chi-Mei

    2002-05-01

    Biofilters do not provide much water for bacteria to grow. To use them efficiently and properly, it is essential to understand the kinetics of water transformation and to control moisture levels. This study aims to clarify whether the metabolism of microorganisms will improve the water-holding capacity of media or will intensify drying. This experiment was conducted in duplicate, that is, both with and without bacterial inoculation. Both the constant water content mode and the declining water content mode show that microbial growth in a log phase will enhance drying. In contrast, the bacteria growing in a logarithmic decline phase will improve water-holding capacity. Basically, water evaporation can result from the latent heat obtained from microbial respiration or from the physical temperature difference between the unsaturated air and the wet media. Two ways that biofilters can gain water are from water incorporated into bacteria cells and from water obtained from the oxidation of volatile organic compounds (VOCs).

  17. Characterization of the denitrifying bacterial community in a full-scale rockwool biofilter for compost waste-gas treatment.

    PubMed

    Yasuda, Tomoko; Waki, Miyoko; Fukumoto, Yasuyuki; Hanajima, Dai; Kuroda, Kazutaka; Suzuki, Kazuyoshi

    2017-07-07

    The potential denitrification activity and the composition of the denitrifying bacterial community in a full-scale rockwool biofilter used for treating livestock manure composting emissions were analyzed. Packing material sampled from the rockwool biofilter was anoxically batch-incubated with (15)N-labeled nitrate in the presence of different electron donors (compost extract, ammonium, hydrogen sulfide, propionate, and acetate), and responses were compared with those of activated sludge from a livestock wastewater treatment facility. Overnight batch-incubation showed that potential denitrification activity for the rockwool samples was higher with added compost extract than with other potential electron donors. The number of 16S rRNA and nosZ genes in the rockwool samples were in the range of 1.64-3.27 × 10(9) and 0.28-2.27 × 10(8) copies/g dry, respectively. Denaturing gradient gel electrophoresis analysis targeting nirK, nirS, and nosZ genes indicated that the distribution of nir genes was spread in a vertical direction and the distribution of nosZ genes was spread horizontally within the biofilter. The corresponding denitrifying enzymes were mainly related to those from Phyllobacteriaceae, Bradyrhizobiaceae, and Alcaligenaceae bacteria and to environmental clones retrieved from agricultural soil, activated sludge, freshwater environments, and guts of earthworms or other invertebrates. A nosZ gene fragment having 99% nucleotide sequence identity with that of Oligotropha carboxidovorans was also detected. Some nirK fragments were related to NirK from micro-aerobic environments. Thus, denitrification in this full-scale rockwool biofilter might be achieved by a consortium of denitrifying bacteria adapted to the intensely aerated ecosystem and utilizing mainly organic matter supplied by the livestock manure composting waste-gas stream.

  18. The use of oak chips and coconut fiber as biofilter media to remove vocs in rendering process.

    PubMed

    Tymczyna, Leszek; Chmielowiec-Korzeniowska, Anna; Paluszak, Zbigniew; Dobrowolska, Magadalena; Banach, Marcin; Pulit, Jolanta

    2013-01-01

    The study evaluated the effectiveness of air biofiltration in rendering plants. The biofilter material comprised compost soil (40%) and peat (40%) mixed up with coconut fiber (medium A) and oak bark (medium B). During biofiltration average VOCs reduction reached 88.4% for medium A and 89.7% for medium B. A positive relationship of aldehyde reduction from material humidity (r = 0.502; α<0.05) was also noted. Other biomaterial parameters did not affect the treatment efficiency.

  19. Enhancing simultaneous nitritation and anammox in recirculating biofilters: effects of unsaturated zone depth and alkalinity dissolution of packing materials.

    PubMed

    Wen, Jianfeng; Tao, Wendong; Wang, Ziyuan; Pei, Yuansheng

    2013-01-15

    This study investigated effects of unsaturated zone depth on nitrogen removal via simultaneous nitritation and anammox in three vertical flow recirculating biofilters. The biofilters had different depths (25, 40, and 60 cm) of an unsaturated zone and the same depth (35 cm) of a saturated zone. Unsaturated zone depth could be regulated to maintain suitable dissolved oxygen concentrations and enhance entrapment of carbon dioxide for co-occurrence of aerobic ammonia oxidation and anammox in the saturated zones. The biofilters with the larger unsaturated zones had higher ammonium and total inorganic nitrogen removal rates (16.2-33.5 g N/m(3)/d and 4.6-16.7 g N/m(3)/d, respectively) than the biofilter with the smallest unsaturated zone (11.9-18.1 g N/m(3)/d and 4.4-7.9 g N/m(3)/d, respectively). Electric arc furnace slag and marble chips were packed in the unsaturated and saturated zones, respectively, as low-cost materials to supplement alkalinity and buffer pH. Laboratory experiments showed that the maximum alkalinity dissolution efficiency was 513 mg CaCO(3)/kg marble chips and 761 mg CaCO(3)/kg electric arc furnace slag. Marble chips and electric arc furnace slag could increase dairy wastewater pH up to 7 and 9, respectively. The laboratory results are also useful for utilization of furnace slag and marble chips in constructed wetlands. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Elimination of hydrophobic volatile organic compounds in fungal biofilters: reducing start-up time using different carbon sources.

    PubMed

    Vergara-Fernández, Alberto; Hernández, Sergio; Revah, Sergio

    2011-04-01

    Fungal biofilters have been recently studied as an alternative to the bacterial systems for the elimination of hydrophobic volatile organic compounds (VOC). Fungi foster reduced transport limitation of hydrophobic VOCs due to their hydrophobic surface and extended gas exchange area associated to the hyphal growth. Nevertheless, one of their principal drawbacks is their slow growth, which is critical in the start-up of fungal biofilters. This work compares the use of different carbon sources (glycerol, 1-hexanol, wheat bran, and n-hexane) to reduce the start-up period and sustain high n-hexane elimination capacities (EC) in biofilters inoculated with Fusarium solani. Four parallel experiments were performed with the different media and the EC, the n-hexane partition coefficient, the biomass production and the specific consumption rate were evaluated. Biofilters were operated with a residence time of 1.3 min and an inlet n-hexane load of 325 g m(-3) (reactor) h(-1). The time to attain maximum EC once gaseous n-hexane was fed was reduced in the three experiments with alternate substrates, as compared to the 36 days needed with the control where only n-hexane was added. The shortest adaptation period was 7 days when wheat bran was initially used obtaining a maximum EC of 160 g m(-3) (reactor) h(-1) and a critical load of 55 g m(-3) (reactor) h(-1). The results were also consistent with the pressure drop, the amount of biomass produced and its affinity for the gaseous n-hexane, as represented by its partition coefficient. Copyright © 2010 Wiley Periodicals, Inc.

  1. Escherichia coli removal in biochar-augmented biofilter: effect of infiltration rate, initial bacterial concentration, biochar particle size, and presence of compost.

    PubMed

    Mohanty, Sanjay K; Boehm, Alexandria B

    2014-10-07

    Bioretention systems and biofilters are used in low impact development to passively treat urban stormwater. However, these engineered natural systems are not efficient at removing fecal indicator bacteria, the contaminants responsible for a majority of surface water impairments. The present study investigates the efficacy of biochar-augmented model sand biofilters for Escherichia coli removal under a variety of stormwater bacterial concentrations and infiltration rates. Additionally, we test the role of biochar particle size and "presence of compost on model" biofilter performance. Our results show that E. coli removal in a biochar-augmented sand biofilter is ∼ 96% and is not greatly affected by increases in stormwater infiltration rates and influent bacterial concentrations, particularly within the ranges expected in field. Removal of fine (<125 μm) biochar particles from the biochar-sand biofilter decreased the removal capacity from 95% to 62%, indicating biochar size is important. Addition of compost to biochar-sand biofilters not only lowered E. coli removal capacity but also increased the mobilization of deposited bacteria during intermittent infiltration. This result is attributed to exhaustion of attachment sites on biochar by the dissolved organic carbon leached from compost. Overall, our study indicates that biochar has potential to remove bacteria from stormwater under a wide range of field conditions, but for biochar to be effective, the size should be small and biochar should be applied without compost. Although the results aid in the optimization of biofilter design, further studies are needed to examine biochar potential in the field over an entire rainy season.

  2. Treatment of dynamic mixture of hexane and benzene vapors in a Trickle Bed Air Biofilter integrated with cyclic adsorption/desorption beds.

    PubMed

    Aly Hassan, Ashraf; Sorial, George A

    2011-01-01

    One of the main challenges that face successful biofiltration is the erratic loading pattern and long starvation periods. However, such patterns are common in practical applications. In order to provide long-term stable operation of a biofilter under these conditions, a cyclic adsorption/desorption beds system with flow switching was installed prior to a biofilter. Different square waves of a mixture containing n-hexane and benzene at a 2:1 ratio were applied to the cyclic adsorption/desorption beds and then fed to a biofilter. The performance of this integrated system was compared to a biofilter unit receiving the same feed of both VOCs. The cyclic adsorption/desorption beds unit successfully achieved its goal of stabilizing erratic loading even with very sharp peaks at the influent concentration equalizing influent concentrations ranging from 10-470 ppmv for n-hexane to 30-1410 ppmv for benzene. The study included different peak concentrations with durations ranging from 6 to 20 min. The cyclic beds buffered the fluctuating influent load and the followed biofilter had all the time a continuous stable flow. Another advantage achieved by the cyclic adsorption/desorption beds was the uninterrupted feed to the biofilter even during the starvation where there was no influent in the feed. The results of the integrated system with regard to removal efficiency and kinetics are comparable to published results with continuous feed studies at the same loading rates. The removal efficiency for benzene had a minimum of 85% while for n-hexane ranged from 50% to 77% according to the loading rate. The control unit showed very erratic performance highlighting the benefit of the utilization of the cyclic adsorption/desorption beds. The biofilter was more adaptable to concentration changes in benzene than n-hexane. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. Ein Unscented Kalman Filter zur Schätzung von Schaltungsnichtidealitäten eines zeitkontinuierlichen Sigma-Delta Wandlers mit impliziter Dezimation

    NASA Astrophysics Data System (ADS)

    Buhmann, A.; Keller, M.; Maurer, M.; Ortmanns, M.; Manoli, Y.

    2008-05-01

    Nichtidealitäten einer Schaltung, wie z.B. nicht ideale Charakteristik des Operationsverstärkers und Streuungen in den Filterkoeffizienten, sind dahingehend bekannt die Effizienz von zeitkontinuierlichen Sigma-Delta Wandlern in drastischer Weise zu reduzieren. Daher stellt diese Veröffentlichung eine mögliche Methode vor, um die genannten Nichtidealitäten durch eine Schätzung mit Hilfe eines Unscented Kalman Filters zu bestimmen und in einem möglichen weiteren Schritt zu korrigieren. Des Weiteren kann durch eine leichte Modifikation des vorgestellten Algorithmus auch gleichzeitig eine implizite Dezimation des Ausgangssignals durchgeführt werden. Hierdurch wird die Gesamteffizienz des vorgestellten Ansatzes gesteigert, da kein zusätzlicher Dezimationsfilter mehr benötigt wird. Simulationsergebnisse des Filteralgorithmus zeigen die prinzipielle Funktion des Algorithmus.

  4. Microbial Biotreatment of Actual Textile Wastewater in a Continuous Sequential Rice Husk Biofilter and the Microbial Community Involved

    PubMed Central

    Lindh, Markus V.; Pinhassi, Jarone; Welander, Ulrika

    2017-01-01

    Textile dying processes often pollute wastewater with recalcitrant azo and anthraquinone dyes. Yet, there is little development of effective and affordable degradation systems for textile wastewater applicable in countries where water technologies remain poor. We determined biodegradation of actual textile wastewater in biofilters containing rice husks by spectrophotometry and liquid chromatography mass spectrometry. The indigenous microflora from the rice husks consistently performed >90% decolorization at a hydraulic retention time of 67 h. Analysis of microbial community composition of bacterial 16S rRNA genes and fungal internal transcribed spacer (ITS) gene fragments in the biofilters revealed a bacterial consortium known to carry azoreductase genes, such as Dysgonomonas, and Pseudomonas and the presence of fungal phylotypes such as Gibberella and Fusarium. Our findings emphasize that rice husk biofilters support a microbial community of both bacteria and fungi with key features for biodegradation of actual textile wastewater. These results suggest that microbial processes can substantially contribute to efficient and reliable degradation of actual textile wastewater. Thus, development of biodegradation systems holds promise for application of affordable wastewater treatment in polluted environments. PMID:28114377

  5. Performance of double-layer biofilter packed with coal fly ash ceramic granules in treating highly polluted river water.

    PubMed

    Jing, Zhaoqian; Li, Yu-You; Cao, Shiwei; Liu, Yuyu

    2012-09-01

    To improve trickling filters' denitrification efficiency, a biofilter with a trickling upper layer and a submerged lower layer was developed and applied in treating highly polluted river water. It was packed with porous coal fly ash ceramic granules. Its start-up characteristics, influence of hydraulic loading rates (HLR), carbon/nitrogen (C/N) ratio and filter depth on pollutants removal were investigated. The results indicated this biofilter was started quickly in 16 days with river sediment as inoculum. Alternating nitrification and denitrification were achieved when water flowed downwards. COD and nitrogen were mainly removed in the upper layer and the lower layer, respectively. With HLR of 4.0-5.0m(3)/(m(2)d), chemical oxygen demand (COD), ammonium (NH(4)(+)-N) and total nitrogen (TN) in the effluent were below 50, 5 and 15 mg/L, respectively. This biofilter removed more than 80% of COD, 85% of NH(4)(+)-N and 60% of TN with C/N ratios ranging from 6 to 10.

  6. Biofilter design for effective nitrogen removal from stormwater - influence of plant species, inflow hydrology and use of a saturated zone.

    PubMed

    Payne, Emily G I; Pham, Tracey; Cook, Perran L M; Fletcher, Tim D; Hatt, Belinda E; Deletic, Ana

    2014-01-01

    The use of biofilters to remove nitrogen and other pollutants from urban stormwater runoff has demonstrated varied success across laboratory and field studies. Design variables including plant species and use of a saturated zone have large impacts upon performance. A laboratory column study of 22 plant species and designs with varied outlet configuration was conducted across a 1.5-year period to further investigate the mechanisms and influences driving biofilter nitrogen processing. This paper presents outflow concentrations of total nitrogen from two sampling events across both 'wet' and 'dry' frequency dosing, and from sampling across two points in the outflow hydrograph. All plant species were effective under conditions of frequent dosing, but extended drying increased variation between species and highlighted the importance of a saturated zone in maintaining biofilter function. The saturated zone also effectively treated the volume of stormwater stored between inflow events, but this extended detention provided no additional benefit alongside the rapid processing of the highest performing species. Hence, the saturated zone reduced performance differences between plant species, and potentially acts as an 'insurance policy' against poor sub-optimal plant selection. The study shows the importance of biodiversity and inclusion of a saturated zone in protecting against climate variability.

  7. Management of Microbial Communities through Transient Disturbances Enhances the Functional Resilience of Nitrifying Gas-Biofilters to Future Disturbances.

    PubMed

    Cabrol, Léa; Poly, Franck; Malhautier, Luc; Pommier, Thomas; Lerondelle, Catherine; Verstraete, Willy; Lepeuple, Anne-Sophie; Fanlo, Jean-Louis; Le Roux, Xavier

    2016-01-05

    Microbial communities have a key role for the performance of engineered ecosystems such as waste gas biofilters. Maintaining constant performance despite fluctuating environmental conditions is of prime interest, but it is highly challenging because the mechanisms that drive the response of microbial communities to disturbances still have to be disentangled. Here we demonstrate that the bioprocess performance and stability can be improved and reinforced in the face of disturbances, through a rationally predefined strategy of microbial resource management (MRM). This strategy was experimentally validated in replicated pilot-scale nitrifying gas-biofilters, for the two steps of nitrification. The associated biological mechanisms were unraveled through analysis of functions, abundances and community compositions for the major actors of nitrification in these biofilters, that is, ammonia-oxidizing bacteria (AOB) and Nitrobacter-like nitrite-oxidizers (NOB). Our MRM strategy, based on the application of successive, transient perturbations of increasing intensity, enabled to steer the nitrifier community in a favorable way through the selection of more resistant AOB and NOB sharing functional gene sequences close to those of, respectively, Nitrosomonas eutropha and Nitrobacter hamburgensis that are well adapted to high N load. The induced community shifts resulted in significant enhancement of nitrification resilience capacity following the intense perturbation.

  8. A two-stage combined trickle bed reactor/biofilter for treatment of styrene/acetone vapor mixtures.

    PubMed

    Vanek, Tomas; Halecky, Martin; Paca, Jan; Zapotocky, Lubos; Gelbicova, Tereza; Vadkertiova, Renata; Kozliak, Evguenii; Jones, Kim

    2015-01-01

    Performance of a two-stage biofiltration system was investigated for removal of styrene-acetone mixtures. High steady-state acetone loadings (above C(in)(Ac) = 0.5 g.m(-3) corresponding to the loadings > 34.5 g.m(-3).h(-1)) resulted in a significant inhibition of the system's performance in both acetone and styrene removal. This inhibition was shown to result from the acetone accumulation within the upstream trickle-bed bioreactor (TBR) circulating mineral medium, which was observed by direct chromatographic measurements. Placing a biofilter (BF) downstream to this TBR overcomes the inhibition as long as the biofilter has a sufficient bed height. A different kind of inhibition of styrene biodegradation was observed within the biofilter at very high acetone loadings (above C(in)(Ac) = 1.1 g.m(-3) or 76 g.m(-3).h(-1) loading). In addition to steady-state measurements, dynamic tests confirmed that the reactor overloading can be readily overcome, once the accumulated acetone in the TBR fluids is degraded. No sizable metabolite accumulation in the medium was observed for either TBR or BF. Analyses of the biodegradation activities of microbial isolates from the biofilm corroborated the trends observed for the two-stage biofiltration system, particularly the occurrence of an inhibition threshold by excess acetone.

  9. Effect of the continuous addition of ozone on biomass clogging control in a biofilter treating ethyl acetate vapors.

    PubMed

    Covarrubias-García, Itzel; Aizpuru, Aitor; Arriaga, Sonia

    2017-04-15

    Biofiltration systems have been recognized as a cost-effective and environmentally friendly control technique for volatile organic compounds (VOC) removal. However, the long-term operation of biofilters causes biomass accumulation, and thus the occurrence of bed clogging, leading to a major decrease in biofilter performance. Control methods have been carried out in order to solve clogging problems, including backwashing, bed stirring, modification of flow patterns, predation, starvation and others. Ozone (O3) has been used in biofiltration systems at low concentrations to control the excess of biomass. It is worth mentioning that all these biofiltration studies involving O3 treated recalcitrant pollutants such as chlorobenzene, formaldehyde and toluene, which do not produce enough biomass to effectively prove clogging prevention. Thus, this study evaluated the effect of the continuous addition of O3 as a chemical oxidant at a very low concentration (90ppbv) as a practical solution to overcoming clogging in a process of biofiltration of ethyl acetate (EA), a readily degradable molecule. The maximum elimination capacities achieved ranged from 200 to 120gm(-3)h(-1), with and without O3, respectively. The biomass concentrations in these systems ranged from 23.3-180.1 to 43.31-288.46mgbiomassgperlite(-1) with and without O3 addition, respectively. Based on the results, it was concluded that the continuous addition of O3 could be an attractive solution to improving biofilter performance and extending the lifetime of the filter bed. Copyright © 2017. Published by Elsevier B.V.

  10. The role of water in the performance of biofilters: parameterization of pressure drop and sorption capacities for common packing materials.

    PubMed

    Dorado, Antonio D; Lafuente, Javier; Gabriel, David; Gamisans, Xavier

    2010-08-15

    The presence of water in a biofilter is critical in keeping microorganisms active and abating pollutants. In addition, the amount of water retained in a biofilter may drastically affect the physical properties of packing materials and packed beds. In this study, the influence of water on the pressure drop and sorption capacities of 10 different packing materials were experimentally studied and compared. Pressure drop was characterized as a function of dynamic hold-up, porosity and gas flow rate. Experimental data were fitted to a mathematical expression based on a modified Ergun correlation. Sorption capacities for toluene were determined for both wet and dry materials to obtain information about the nature of interactions between the contaminant, the packing materials and the aqueous phase. The experimental sorption capacities of materials were fitted to different isotherm models for gas adsorption in porous materials. The corresponding confidence interval was determined by the Fisher information matrix. The results quantified the dynamic hold-up effect resulting from the significant increase in the pressure drop throughout the bed, i.e. the financial cost of driving air, and the negative effect of this air on the total amount of hydrophobic pollutant that can be adsorbed by the supports. Furthermore, the results provided equations for ascertaining water presence and sorption capacities that could be widely used in the mathematical modeling of biofilters.

  11. Biofilters for stormwater harvesting: understanding the treatment performance of key metals that pose a risk for water use.

    PubMed

    Feng, Wenjun; Hatt, Belinda E; McCarthy, David T; Fletcher, Tim D; Deletic, Ana

    2012-05-01

    A large-scale stormwater biofilter column study was conducted to evaluate the impact of design configurations and operating conditions on metal removal for stormwater harvesting and protection of aquatic ecosystems. The following factors were tested over 8 months of operation: vegetation selection (plant species), filter media type, filter media depth, inflow volume (loading rate), and inflow pollutant concentrations. Operational time was also integrated to evaluate treatment performance over time. Vegetation and filter type were found to be significant factors for treatment of metals. A larger filter media depth resulted in increased outflow concentrations of iron, aluminum, chromium, zinc, and lead, likely due to leaching and mobilization of metals within the media. Treatment of all metals except aluminum and iron was generally satisfactory with respect to drinking water quality standards, while all metals met standards for irrigation. However, it was shown that biofilters could be optimized for removal of iron to meet the required drinking water standards. Biofilters were generally shown to be resilient to variations in operating conditions and demonstrated satisfactory removal of metals for stormwater-harvesting purposes.

  12. Reduction of toxic products and bioaerosol emission of a combined ultraviolet-biofilter process for chlorobenzene treatment.

    PubMed

    Wang, Can; Xi, Jin-Ying; Hu, Hong-Ying

    2009-04-01

    A combined process involving ultraviolet (UV) photodegradation and biofiltration was developed to treat gaseous chlorobenzene. The toxicity of the photodegradation products and the bioaerosol emissions from the biofilter were investigated. The experimental results showed that a standalone UV photodegradation of chlorobenzene can result in products having significant acute toxicity and genotoxicity, whereas a biofiltration process can produce a high concentration of bioaerosols, which are a potential health risk. In the combined process, the toxic products produced by the UV photodegradation were removed by the subsequent biofilter. The acute toxicity of the products was reduced from 0.042 to 0.005 mg zinc/mg total organic carbon (TOC). Also the genotoxicity was reduced from 0.76 to 0.16 microg 4-nitroquinoline-N-oxide per milligram TOC. On the other hand, the bioaerosol concentration emitted from the biofilter decreased from 1.38 x 10(3) colony-forming units (CFU) x m(-3) (without UV pretreatment) to 60 CFU x m(-3) (with UV pretreatment), nearly the same as the background level of 40 CFU x m(-3). The significant decrease in bioaerosol emission might be due to a high concentration of ozone (50 mg x m(-3) or 25 parts per million by volume produced by the UV pretreatment. Hence, the UV photodegradation and biofiltration process exhibited synergistic effects. Also, the combined UV-biofiltration process was ecologically safer and exhibited a lower degree of infectivity as compared with standalone UV or biofiltration processes.

  13. A laboratory-scale comparison of compost and sand--compost--perlite as methane-oxidizing biofilter media.

    PubMed

    Philopoulos, Andrew; Ruck, Juliane; McCartney, Daryl; Felske, Christian

    2009-03-01

    Municipal solid waste landfills produce methane, a potent greenhouse gas. A treatment approach is to passively vent landfill gas through a methane-oxidizing biofilter medium, a porous substrate that facilitates the growth of methanotrophic bacteria. Two substrates, compost and a sand-compost-perlite (SCP) mixture, were evaluated in a laboratory-scale experiment for their suitability as biofilter media. The SCP mixture was investigated to minimize settlement and was based on a particle size distribution specification used for turf grass. The long-term (218 days) methane removal rates showed that both compost and SCP were capable of removing 100% of the methane influent flux (134 g CH(4) m( -2) day(-1)). The post-experiment analysis showed that compost had compacted more than SCP. This did not affect the results; however, in a field installation, traffic on the biofilter surface (e.g. maintenance) could cause further compaction and negatively affect performance. Exopolymeric substance produced by the methanotrophic bacteria, attributed by others for declining removal rates due to bio-clogging, was not observed to affect the results. The maximum exopolymeric substance values measured were 23.9 and 7.8 mg D-glucose g(-1) (dry basis) for compost and SCP, respectively.

  14. Microbial Biotreatment of Actual Textile Wastewater in a Continuous Sequential Rice Husk Biofilter and the Microbial Community Involved.

    PubMed

    Forss, Jörgen; Lindh, Markus V; Pinhassi, Jarone; Welander, Ulrika

    2017-01-01

    Textile dying processes often pollute wastewater with recalcitrant azo and anthraquinone dyes. Yet, there is little development of effective and affordable degradation systems for textile wastewater applicable in countries where water technologies remain poor. We determined biodegradation of actual textile wastewater in biofilters containing rice husks by spectrophotometry and liquid chromatography mass spectrometry. The indigenous microflora from the rice husks consistently performed >90% decolorization at a hydraulic retention time of 67 h. Analysis of microbial community composition of bacterial 16S rRNA genes and fungal internal transcribed spacer (ITS) gene fragments in the biofilters revealed a bacterial consortium known to carry azoreductase genes, such as Dysgonomonas, and Pseudomonas and the presence of fungal phylotypes such as Gibberella and Fusarium. Our findings emphasize that rice husk biofilters support a microbial community of both bacteria and fungi with key features for biodegradation of actual textile wastewater. These results suggest that microbial processes can substantially contribute to efficient and reliable degradation of actual textile wastewater. Thus, development of biodegradation systems holds promise for application of affordable wastewater treatment in polluted environments.

  15. Synthese von analogen Filtern auf einer rekonfigurierbaren Hardware-Architektur mittels eines Genetischen Algorithmus

    NASA Astrophysics Data System (ADS)

    Trendelenburg, S.; Becker, J.; Henrici, F.; Manoli, Y.

    2008-05-01

    Rekonfigurierbare Analog-Arrays (FPAAs) sind der Versuch, die Vorteile der aus der digitalen Welt bekannten FPGAs (Flexibilität, Entwurfsgeschwindigkeit) auch für analoge Anwendungen verfügbar zu machen. Aufgrund der Vielfalt der analogen Schaltungstechnik ist die Abbildung von vorgegebenen Schaltungskonzepten auf eine FPAA-Architektur nicht immer einfach lösbar. Diese Arbeit stellt einen neuen Ansatz für die Synthese von Filtern auf einer FPAA-Architektur für zeitkontinuierliche Analogfilter mittels eines Genetischen Algorithmus (GA) vor. Anhand eines Matlab-Modells des FPAA, das eine gute übereinstimmung mit Simulationen des FPAA auf Transistorebene aufweist, wurde gezeigt, dass eine große Vielzahl verschiedener Filterstrukturen auf dieser Architektur dargestellt werden kann. Daraufhin wurde ein Genetischer Algorithmus entwickelt, der es erlaubt, aus einer gegebenen Filterspezifikation Konfigurationsdatensätze zu synthetisieren, die den gewünschten Filter auf die FPAA-Architektur abbilden.

  16. Fungal removal of gaseous hexane in biofilters packed with poly(ethylene carbonate) pine sawdust or peat composites.

    PubMed

    Hernández-Meléndez, Oscar; Bárzana, Eduardo; Arriaga, Sonia; Hernández-Luna, Martín; Revah, Sergio

    2008-08-01

    The removal of volatile organic compounds (VOC) in biofilters packed with organic filter beds, such as peat moss (PM) and pine sawdust (PS), frequently presents drawbacks associated to the collapse of internal structures affecting the long-term operation. Poly(ethylene ether carbonate) (PEEC) groups grafted to these organic carriers cross linked with 4,4'-methylenebis(phenylisocyanate) (MDI) permitted fiber aggregation into specific shapes and with excellent hexane sorption performance. Modified peat moss (IPM) showed very favorable characteristics for rapid microbial development. Water-holding capacity in addition to hexane adsorption almost equal to the dry samples was obtained. Pilot scale hexane biofiltration experiments were performed with the composites after inoculation with the filamentous fungus Fusarium solani. During the operation of the biofilter under non-aseptic conditions, the addition of bacterial antibiotics did not have a relevant effect on hexane removal, confirming the role of fungi in the uptake of hexane and that bacterial growth was intrinsically limited by an adequate performance of the composites. IPM biofilter had a start-up period of 8-13 days with concurrent CO(2) production of approximately 90 g m(-3) h(-1) at day 11. The final pressure drop after 70 days of operation was 5.3 mmH(2)O m(-1) reactor. For modified pine sawdust (IPS) packed biofilter, 5 days were required to develop an EC of about 100 g m(-3) h(-1) with an inlet hexane load of approximately 190 g m(-3) h(-1). Under similar conditions, 12-17 days were required to observe a significant start-up in the reference perlite biofilter to reach gradually an EC of approximately 100 g m(-3) h(-1) at day 32. Under typical biofiltration conditions, the physical-chemical properties of the modified supports maintained a minimum water activity (a(w)) of 0.925 and a pH between 4 and 5.5, which allowed the preferential fungal development and limited bacterial growth.

  17. Apple EIN3 BINDING F-box 1 inhibits the activity of three apple EIN3-like transcription factors

    PubMed Central

    Tacken, Emma J.; Ireland, Hilary S.; Wang, Yen-Yi; Putterill, Jo; Schaffer, Robert J.

    2012-01-01

    Background and aims Fruit ripening in Malus× domestica (apple) is controlled by ethylene. Work in model species has shown that following the detection of ethylene, the ETHYLENE INSENSITIVE 3 (EIN3) transcription factor is stabilized, leading to an increase in transcript accumulation of ethylene-responsive genes, such as POLYGALACTURONASE1 (PG1). In the absence of ethylene, the EIN3 BINDING F-box (EBF) proteins rapidly degrade EIN3 via the ubiquitination/SCF (Skp, Cullin, F-Box) proteasome pathway. In this study, we aim to identify and characterize the apple EBF genes, and test their activity against apple EIN3-like proteins (EILs). Methodology The apple genome sequence was mined for EBF-like genes. The expression of EBF-like genes was measured during fruit development. Using a transient assay in Nicotiana benthamiana leaves, the activity of three apple EILs was tested against the PG1 promoter, with and without ethylene and EBF1. Principal results Four EBF-like genes in apple were identified and grouped into two sub-clades. Sub-clade I genes had constant expression over fruit development while sub-clade II genes increased in expression at ripening. EBF1 was shown to reduce the transactivation of the apple PG1 promoter by the EIL1, EIL2 and EIL3 transcription factors in the presence of ethylene. Conclusions The apple EBF1 gene identified here is likely to be a functionally conserved EBF orthologue, modulating EIL activity in apples. The activity of EBF1 suggests that it is not specific to a single EIL, instead acting as a global regulator of apple EIL transcription factors. PMID:23585922

  18. Effects of inorganic nitrogen (NH₄Cl) and biodegradable organic carbon (CH₃COONa) additions on a pilot-scale seawater biofilter.

    PubMed

    Xavier Simon, F; Rudé, Elisabet; Berdalet, Elisa; Llorens, Joan; Baig, Sylvie

    2013-05-01

    Biofilters degrade a small fraction of the natural organic matter (NOM) contained in seawater which is the leading cause of biofouling in downstream processes. This work studies the effects of chemical additions on NOM biodegradation by biofilters. In this work, biofiltration of seawater with an empty bed contact time (EBCT) of 6 min and a hydraulic loading rate of 10 mh(-1) reduces the biological oxygen demand (BOD7) by 8%, the dissolved organic carbon (DOC) by 6% and the UV absorbance at 254 nm (A₂₅₄) by 7%. Different amounts of ammonium chloride are added to the seawater (up to twice the total dissolved nitrogen in untreated seawater) to study its possible effect on the removal of NOM by a pilot-scale biofilter. Seawater is amended with different amounts of easily biodegradable dissolved organic carbon (BDOC) supplied as sodium acetate (up to twice the DOC) for the same purpose. The results of this work reveal that the ammonium chloride additions do not significantly affect NOM removal and the sodium acetate is completely consumed by the biofiltration process. For both types of chemical additions, the BOD₇, DOC and A₂₅₄ in the outlet stream of the biofilter are similar to the values for the untreated control. These results indicate that this biofilter easily removes the BDOC from the seawater when the EBCT is not above 6 min. Furthermore, nitrogen does not limit the NOM biodegradation in seawater under these experimental conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Evaluation of bioaerosol exposures during conditioning of biofilter organic media beds.

    PubMed

    Barth, Ed; Talbott, Nancy; Gable, Robert; Richter, Sheri; Reponen, Tiina

    2002-01-01

    Biological media air filters (biofilters) are currently being used for the treatment of inorganic and organic gases from sewage treatment plants, industrial processes, and remediation systems. The media may be organic material such as compost, wood chips, or synthetic plastic media, each with a large surface area for microorganism growth and activity. An occupational health and safety graduate student team (OHS team) evaluated potential particulate and bioaerosol exposure from a biofilter unit process used to treat hydrogen sulfide (H2S) gas generated from a primary sludge settling unit process. The OHS team included an industrial hygiene/environmental health engineering specialist, an occupational safety specialist, an occupational health physician, and an occupational health nurse. Concerns were raised regarding the possibility of adverse health effects to maintenance workers during "conditioning" of the biofilter compost-like media beds. Conditioning activities may include in-situ rearrangement of the existing media, removal from the tank/surface, drying/reinsertion of the existing media, or complete removal of the media, and replacement with new. Neither the design engineering firm nor the manufacturer had specific written recommendations or precautions regarding exposure during the conditioning of the compost beds. No personal protection equipment has been used for this activity. The expected agents for adverse health effects associated with this unit process are respirable particulate dust and bioaerosols, which may contain viable bacteria and fungi, as well as endotoxin. Safety procedures are already in place for H2S. Mixed dust from the compost media bed may cause irritation of pre-existing health conditions such as asthma, chronic lung disease, and some skin conditions, and may also lead to new health problems such as inhalation fever, occupational asthma, hypersensitivity pneumonitis, skin rashes and/or skin infections, and upper or lower respiratory

  20. Effects of biofilter media depth and moisture content on removal of gases from a swine barn.

    PubMed

    Liu, Tongshuai; Dong, Hongmin; Zhu, Zhiping; Shang, Bin; Yin, Fubin; Zhang, Wanqin; Zhou, Tanlong

    2017-04-28

    Media depth (MD) and moisture content (MC) are two important factors that greatly influence biofilters performance. The purpose of this study was to investigate the combined effect of MC and MD on removing ammonia (NH3), hydrogen sulfide (H2S), and nitrous oxide (N2O) from swine barns. Biofiltration performance of different MDs and MCs combination based on the mixed medium of wood chips and compost were monitored. A 3×3 factorial design was adopted, which included three levels of the two factors (MC: 45%, 55%, and 67% (wet basis); MD: 0.17, 0.33, and 0.50 m). Results indicated that high MC and MD could improve NH3 removal efficiency, but increase outlet N2O concentration. When MC was 67%, the average NH3 removal efficiency of three MDs (0.17, 0.33, and, 0.50 m) ranged from 77.4% to 78.7%; and the range of average H2S removal efficiency dropped from 68.1%-90.0% (1-34 days of the test period) to 36.8%-63.7% (35-58 days of the test period); and the average outlet N2O concentration increased by 25.5%-60.1%. When MC was 55%, the average removal efficiency of NH3, H2S, and N2O for treatment with 0.33 m MD was 72.8%±5.9%, 70.9%±13.3%, and ?18.9%±8.1%, respectively; and the average removal efficiency of NH3, H2S, and N2O for treatment with 0.50 m MD was 77.7%±4.2%, 65.8%±13.7%, and ?24.5%±12.1%, respectively. When MC was 45%, the highest average NH3 reduction efficiency among three MDs was 60.7% for 0.5 m MD, and the average N2O removal efficiency for three MDs ranged from ?18.8% to ?12.7%. In addition, the pressure drop of 0.33 m MD was significantly lower than that of 0.50 m MD (P < 0.05). To obtain high mitigation of NH3 and H2S and avoid elevated emission of N2O and large pressure drop, 0.33 m MD at 55% MC is recommended. Implications The performances of biofilters with three different media depths (0.17, 0.33, and 0.50 m) and three different media moisture contents (45%, 55%, and 67% (wet basis)) were compared to remove gases from a swine barn. Using wood chips

  1. Freshwater Recirculating Aquaculture System Operations Drive Biofilter Bacterial Community Shifts around a Stable Nitrifying Consortium of Ammonia-Oxidizing Archaea and Comammox Nitrospira.

    PubMed

    Bartelme, Ryan P; McLellan, Sandra L; Newton, Ryan J

    2017-01-01

    Recirculating aquaculture systems (RAS) are unique engineered ecosystems that minimize environmental perturbation by reducing nutrient pollution discharge. RAS typically employ a biofilter to control ammonia levels produced as a byproduct of fish protein catabolism. Nitrosomonas (ammonia-oxidizing), Nitrospira, and Nitrobacter (nitrite-oxidizing) species are thought to be the primary nitrifiers present in RAS biofilters. We explored this assertion by characterizing the biofilter bacterial and archaeal community of a commercial scale freshwater RAS that has been in operation for >15 years. We found the biofilter community harbored a diverse array of bacterial taxa (>1000 genus-level taxon assignments) dominated by Chitinophagaceae (~12%) and Acidobacteria (~9%). The bacterial community exhibited significant composition shifts with changes in biofilter depth and in conjunction with operational changes across a fish rearing cycle. Archaea also were abundant, and were comprised solely of a low diversity assemblage of Thaumarchaeota (>95%), thought to be ammonia-oxidizing archaea (AOA) from the presence of AOA ammonia monooxygenase genes. Nitrosomonas were present at all depths and time points. However, their abundance was >3 orders of magnitude less than AOA and exhibited significant depth-time variability not observed for AOA. Phylogenetic analysis of the nitrite oxidoreductase beta subunit (nxrB) gene indicated two distinct Nitrospira populations were present, while Nitrobacter were not detected. Subsequent identification of Nitrospira ammonia monooxygenase alpha subunit genes in conjunction with the phylogenetic placement and quantification of the nxrB genotypes suggests complete ammonia-oxidizing (comammox) and nitrite-oxidizing Nitrospira populations co-exist with relatively equivalent and stable abundances in this system. It appears RAS biofilters harbor complex microbial communities whose composition can be affected directly by typical system operations while

  2. Freshwater Recirculating Aquaculture System Operations Drive Biofilter Bacterial Community Shifts around a Stable Nitrifying Consortium of Ammonia-Oxidizing Archaea and Comammox Nitrospira

    PubMed Central

    Bartelme, Ryan P.; McLellan, Sandra L.; Newton, Ryan J.

    2017-01-01

    Recirculating aquaculture systems (RAS) are unique engineered ecosystems that minimize environmental perturbation by reducing nutrient pollution discharge. RAS typically employ a biofilter to control ammonia levels produced as a byproduct of fish protein catabolism. Nitrosomonas (ammonia-oxidizing), Nitrospira, and Nitrobacter (nitrite-oxidizing) species are thought to be the primary nitrifiers present in RAS biofilters. We explored this assertion by characterizing the biofilter bacterial and archaeal community of a commercial scale freshwater RAS that has been in operation for >15 years. We found the biofilter community harbored a diverse array of bacterial taxa (>1000 genus-level taxon assignments) dominated by Chitinophagaceae (~12%) and Acidobacteria (~9%). The bacterial community exhibited significant composition shifts with changes in biofilter depth and in conjunction with operational changes across a fish rearing cycle. Archaea also were abundant, and were comprised solely of a low diversity assemblage of Thaumarchaeota (>95%), thought to be ammonia-oxidizing archaea (AOA) from the presence of AOA ammonia monooxygenase genes. Nitrosomonas were present at all depths and time points. However, their abundance was >3 orders of magnitude less than AOA and exhibited significant depth-time variability not observed for AOA. Phylogenetic analysis of the nitrite oxidoreductase beta subunit (nxrB) gene indicated two distinct Nitrospira populations were present, while Nitrobacter were not detected. Subsequent identification of Nitrospira ammonia monooxygenase alpha subunit genes in conjunction with the phylogenetic placement and quantification of the nxrB genotypes suggests complete ammonia-oxidizing (comammox) and nitrite-oxidizing Nitrospira populations co-exist with relatively equivalent and stable abundances in this system. It appears RAS biofilters harbor complex microbial communities whose composition can be affected directly by typical system operations while

  3. Evaluation of compost and a mixture of compost and activated carbon as biofilter media for the treatment of indoor air pollution.

    PubMed

    Ondarts, M; Hort, C; Sochard, S; Platel, V; Moynault, L; Seby, F

    2012-01-01

    Indoor air pollution (IAP), defined by a lot of pollutants at low concentrations (microg m(-3)), is recognized as a major environmental health issue. In order to remove this pollution, biofiltration was investigated in this study. Two biofilters packed with compost and a mixture of compost and activated carbon (AC) were compared during the treatment of an influent with characteristics close to those of IAP. Very high removal efficiencies (RE) were achieved for the two biofilters (RE more than 90% for butyl acetate, butanol, formaldehyde, limonene, toluene and undecane at mass loading from 6-24mg m(-3) h(-1) and 19s empty bed retention time). The fact that high RE of hydrophobic compounds (undecane and limonene) were achieved, along with the results of an abiotic sorption study, lead us to suggest a mechanism including adsorption followed by biodegradation at the interface of the biofilm where microorganisms tend to concentrate near the available substrate. Both chemical reactions with the packing materials and biological degradation led to average RE greater than 91.4% for nitrogen dioxide. It was observed that adding AC to compost had significant effects. First, its buffering capacity led to shorter acclimation duration and more stable operation efficiencies than for the compost biofilter. Secondly, the only compound which was not removed by the compost biofilter, trichloroethylene, was strongly adsorbed by the compost/AC biofilter. Finally, the concentration profile along the two biofilters demonstrated that adding of AC could lead to a reduction of the retention time required to reach the maximal RE.

  4. Soluble microbial products in pilot-scale drinking water biofilters with acetate as sole carbon source.

    PubMed

    Zhang, Ying; Ye, Chengsong; Gong, Song; Wei, Gu; Yu, Xin; Feng, Lin

    2013-04-01

    A comprehensive study on formation and characteristics of soluble microbial products (SMP) during drinking water biofiltration was made in four parallel pilot-scale ceramic biofilters with acetate as the substrate. Excellent treatment performance was achieved while microbial biomass and acetate carbon both declined with the depth of filter. The SMP concentration was determined by calculating the difference between the concentration of dissolved organic carbon (DOC), biodegradable dissolved organic carbon (BDOC) and acetate carbon. The results revealed that SMP showed an obvious increase from 0 to 100 cm depth of the filter. A rising specific ultraviolet absorbance (SUVA) was also found, indicating that benzene or carbonyl might exist in these compounds. SMP produced during this drinking water biological process were proved to have weak mutagenicity and were not precursors of by-products of chlorination disinfection. The volatile parts of SMP were half-quantity analyzed and most of them were dicarboxyl acids, others were hydrocarbons or benzene with 16-17 carbon atoms.

  5. Vapor-phase biofilters make bid for VOC control in industrial applications

    SciTech Connect

    Stewart, W.C.; Thom, R.R.

    1996-09-01

    Biofiltration of contaminated air streams containing volatile organic compounds (VOCs) is a relatively new application of biotechnology in the waste management industry. The primary stimulus for development of vapor-phase biofiltration in Europe is its capability for efficient and reliable VOC destruction without forming hazardous by-products, coupled with low operating and life-cycle costs compared to conventional physical-chemical alternatives. The filters operate by passing the contaminated air stream through a bed of compost, peat, soil or other permeate material, which acts as an attachment site for rich microbial fauna. After the VOCs have been sorbed from the air stream while passing through the bed, the microorganisms use the sorbed organics as a food source, converting the pollutant into carbon dioxide and water vapor. As the organic pollutant is metabolized, the binding site to which it was attached again becomes available to strip additional VOC molecules from the incoming air stream. Thus, the biofilters reach a steady state, and sorption and biological destruction is followed by re-sorption of fresh volatile pollutants. Under proper conditions, this sequence of reactions occurs quite rapidly.

  6. Composition and dynamics of microbial community in a zeolite biofilter-membrane bioreactor treating coking wastewater.

    PubMed

    Zhu, Xiaobiao; Tian, Jinping; Liu, Cong; Chen, Lujun

    2013-10-01

    In this study, a lab-scale anaerobic/anoxic/zeolite biofilter-membrane bioreactor (A1/A2/ZB-MBR) was designed to treat coking wastewater. The 454 pyrosequencing was used to obtain the composition and dynamics of microbial community about the treatment system. The results showed that the system yielded stable effluent chemical oxidation demand (158.5 ± 21.8 mg/L) and ammonia (8.56 ± 7.30 mg/L), but fluctuant total nitrogen (31.4-165.1 mg/L) concentrations. In addition, 66,256 16S rRNA gene sequences were obtained from A2 and ZB-MBR, and the microbial diversity and richness for five samples were determined. Although community compositions in the five samples were quite different, bacteria assigned to phylum Proteobacteria and class Flavobacteria commonly existed and dominated the microbial populations. The pyrosequencing analysis revealed that the microbial community shifted in the ZB-MBR with the presence of zeolite. Some taxa began to appear in ZB-MBR and contributed to the system performance. Additionally, Nitrosomonas and Nitrobacter gradually became the dominant ammonia-oxidizing bacteria and nitrite-oxidizing bacteria during the operation, respectively, which are favorable for the stabilized ammonia removal. Our results proved that the ZB-MBR is an alternative technique for treating coking wastewater.

  7. Submerged aerated bio-filter (SAB)--a post treatment option for UASB effluent treating sewage.

    PubMed

    Sudhir, Padigala; Gaur, Rubia Zahid; Khan, Abid Ali; Kazmi, A A; Mehrotra, Indu

    2013-07-01

    This paper presents exploratory results of the performance of submerged aerated bio-filter (SAB-1.5 L) for the post treatment of UASB effluent treating sewage in order to bring the effluent quality in compliance with discharge standards. The study was carried out in three stages with varied dissolved oxygen (DO) levels of 0 to 2.0, 2.0 to 4.0, 4.0 to 6.0 and > 6.0 mg/L. The hydraulic retention time (HRT) and hydraulic loading rate (HLR) were maintained 0.67 h & 0.1 m3/ m2 x h respectively in all stage of study. The performance in terms of BOD removal efficiency was increased with increase in DO levels. Results revealed that the average BOD and SS removal efficiencies in phases 3 and 4 were 51.3 and 59.5% and 58.8 and 67.5% respectively. Significant ammonical nitrogen (NH4-N) removal of 60% was observed in phase 4. The BOD and SS in phases 3 and 4 were reduced to well below the effluent disposal standards. The SAB at DO ≥ 4 mg/L can be considered a viable alternative for the post treatment of effluent from UASB treating domestic wastewater.

  8. Use of aged refuse-based bioreactor/biofilter for landfill leachate treatment.

    PubMed

    Hassan, Muhammad; Xie, Bing

    2014-08-01

    Sanitary landfilling is a proven way for disposal of municipal solid waste (MSW) in developed countries in general and in developing countries in particular, owing to its low immediate costs. On the other hand, landfilling is a matter of concern due to its generation of heavily polluted leachate. Landfill leachate becomes more refractory with time and is very difficult to treat using conventional biological processes. The aged refuse-based bioreactor/biofilter (ARB) has been shown to be a promising technology for the removal of various pollutants from landfill leachate and validates the principle of waste control by waste. Based on different environmental and operational factors, many researchers have reported remarkable pollutant removal efficiencies using ARB. This paper gives an overview of various types of ARBs used; their efficiencies; and certain factors like temperatures, loading rates, and aerobic/anaerobic conditions which affect the performance of ARBs in eliminating pollutants from leachate. Treating leachate by ARBs has been proved to be more cost-efficient, environment friendly, and simple to operate than other traditional biological techniques. Finally, future research and developments are also discussed.

  9. Dynamic model for nitric oxide removal by a rotating drum biofilter.

    PubMed

    Chen, Jun; Jiang, Yifeng; Chen, Jianmeng; Sha, Haolei; Zhang, Wei

    2009-09-15

    To illustrate the process of nitric oxide (NO) denitrifying removal by a novel rotating drum biofilter (RDB), a dynamic model has been developed and further validated. Based on the mass component profile of NO at the gas-liquid interface combined with a Monod kinetic equation, the model was used to depict the mass transfer-reaction process of NO in RDB, focusing on the concentration distribution of NO in the gas, liquid, and biofilm phases. The NO distribution equation on the biofilm carrier was thereby achieved, as well as a dynamic model for NO elimination in the test system. Additionally, effects of operating parameters such as inlet NO concentration and empty-bed residence time on NO removal efficiency were evaluated through a sensitivity analysis of the model. The model was then modified taking the absorption of NO by nutrition liquid in the bottom of RDB into consideration. The results showed that the simulated data agreed well with the experimental data. The model made it possible to simulate a relatively high NO removal efficiency by RDB.

  10. Optimizing and real-time control of biofilm formation, growth and renewal in denitrifying biofilter.

    PubMed

    Liu, Xiuhong; Wang, Hongchen; Long, Feng; Qi, Lu; Fan, Haitao

    2016-06-01

    A pilot-scale denitrifying biofilter (DNBF) with a treatment capacity of 600m(3)/d was used to study real-time control of biofilm formation, removal and renewal. The results showed biofilm formation, growth and removal can be well controlled using on-line monitored turbidity. The status of filter layer condition can be well indicated by Turb break points on turbidity profile. There was a very good linear relationship between biofilm growth degree (Xbiof) and filter clogging degree (Cfilter) with R(2) higher than 0.99. Filter layer clogging coefficient (Yc) lower than 0.27 can be used to determine stable filter layer condition. Since variations of turbidity during backwash well fitted normal distribution with R(2) higher than 0.96, biofilm removal during backwash also can be well optimized by turbidity. Although biofilm structure and nirK-coding denitrifying communities using different carbon sources were much more different, DNBF was still successfully and stably optimized and real-time controlled via on-line turbidity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Enhanced phosphorus recovery and biofilm microbial community changes in an alternating anaerobic/aerobic biofilter.

    PubMed

    Tian, Qing; Ong, Say Kee; Xie, Xuehui; Li, Fang; Zhu, Yanbin; Wang, Feng Rui; Yang, Bo

    2016-02-01

    The operation of an alternating anaerobic/aerobic biofilter (AABF), treating synthetic wastewater, was modified to enhance recovery of phosphorus (P). The AABF was periodically fed with an additional carbon source during the anaerobic phase to force the release of biofilm-sequestered P which was then harvested and recovered. A maximum of 48% of the total influent P was found to be released in the solution for recovery. Upon implementation of periodic P bio-sequestering and P harvesting, the predominant bacterial communities changed from β-Proteobacteria to γ-Proteobacteria groups. The genus Pseudomonas of γ-Proteobacteria was found to enrich greatly with 98% dominance. Dense intracellular poly-P granules were found within the cells of the biofilm, confirming the presence of P accumulating organisms (PAOs). Periodic addition of a carbon source to the AABF coupled with intracellular P reduction during the anaerobic phase most probably exerted environmental stress in the selection of Pseudomonas PAOs over PAOs of other phylogenic types. Results of the study provided operational information on the selection of certain microbial communities for P removal and recovery. This information can be used to further advance P recovery in biofilm systems such as the AABFs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Nitrate and COD removal in an upflow biofilter under an aerobic atmosphere.

    PubMed

    Ji, Bin; Wang, Hongyu; Yang, Kai

    2014-04-01

    A continuous-upflow submerged biofilter packed with ceramsite was constructed for nitrate removal under an aerobic atmosphere. Pseudomonas stutzeri X31, an aerobic denitrifier isolate, was added to the bioreactor as an inoculum. The influent NO3(-)-N concentrations were 63.0-73.8 mg L(-1). The best results were achieved when dissolved oxygen level was 4.6 mg L(-1) and C/N ratio was 4.5. The maximum removal efficiencies of carbon oxygen demand (COD) and NO3(-)-N were 94.04% and 98.48%, respectively at 30°C, when the hydraulic load was 0.75 m h(-1). The top section of the bioreactor possessed less biofilm but higher COD and NO3(-)-N removal rates than the bottom section. Polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) technique combined with electron microscopic examination indicated P. stutzeri X31 and Paracoccus versutus were the most dominant bacteria. Amoeba sp., Vorticella sp., Philodina sp., and Stephanodiscus sp. were also found in the bioreactor. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. A combined upflow anaerobic sludge bed and trickling biofilter process for the treatment of swine wastewater.

    PubMed

    Zhao, Bowei; Li, Jiangzheng; Buelna, Gerardo; Dubé, Rino; Le Bihan, Yann

    2016-01-01

    A combined upflow anaerobic sludge blanket (UASB)-trickling biofilter (TBF) process was constructed to treat swine wastewater, a typical high-strength organic wastewater with low carbon/nitrogen ratio and ammonia toxicity. The results showed that the UASB-TBF system can remarkably enhance the removal of pollutants in the swine wastewater. At an organic loading rate of 2.29 kg/m(3) d and hydraulic retention time of 48 h in the UASB, the chemical oxygen demand (COD), Suspended Solids and Total Kjeldahl Nitrogen removals of the combined process reached 83.6%, 84.1% and 41.2%, respectively. In the combined system the UASB served as a pretreatment process for COD removal while nitrification and denitrification occurred only in the TBF process. The TBF performed reasonably well at a surface hydraulic load as high as 0.12 m(3)/m(2) d. Since the ratio of influent COD to total mineral nitrogen was less than 3.23, it is reasonable to suggest that the wood chips in TBF can serve as a new carbon source for denitrification.

  14. Evaluation of aerated biofilter systems for microbial methane oxidation of poor landfill gas.

    PubMed

    Haubrichs, R; Widmann, R

    2006-01-01

    In the long-term, landfills are producing landfill gas (LFG) with low calorific values. Therefore, the utilization of LFG in combined heat and power plants (CHP) is limited to a certain period of time. A feasible method for LFG treatment is microbial CH(4) oxidation. Different materials were tested in actively aerated lab-scale bio-filter systems with a volume of 0.167 m(3). The required oxygen for the microbial CH(4) oxidation was provided through perforated probes, which distributed ambient air into the filter material. Three air input levels were installed along the height of the filter, each of them adjusted to a particular flow rate. During the tests, stable degradation rates of around 28 g/(m(3) h) in a fine-grained compost material were observed at a CH(4) inlet concentration of 30% over a period of 148 days. Compared with passive (not aerated) tests, the CH(4) oxidation rate increased by a factor of 5.5. Therefore, the enhancement of active aeration on the microbial CH(4) oxidation was confirmed. At a O(2)/CH(4) ratio of 2.5, nearly 100% of the CH(4) load was decomposed. By lowering the ratio from 2.5 to 2, the efficiency fell to values from 88% to 92%. By varying the distribution to the three air input levels, the CH(4) oxidation process was spread more evenly over the filter volume.

  15. Mesquite wood chips (Prosopis) as filter media in a biofilter system for municipal wastewater treatment.

    PubMed

    Sosa-Hernández, D B; Vigueras-Cortés, J M; Garzón-Zúñiga, M A

    2016-01-01

    The biofiltration system over organic bed (BFOB) uses organic filter material (OFM) to treat municipal wastewater (MWW). This study evaluated the performance of a BFOB system employing mesquite wood chips (Prosopis) as OFM. It also evaluated the effect of hydraulic loading rates (HLRs) in order to achieve the operational parameters required to remove organic matter, suspended material, and pathogens, thus meeting Mexican and US regulations for reuse in irrigation. Two biofilters (BFs) connected in series were installed; the first one aerated (0.62 m(3)air m(-2)h(-1)) and the second one unaerated. The source of MWW was a treatment plant located in Durango, Mexico. For 200 days, three HLRs (0.54, 1.07, and 1.34 m(3)m(-2)d(-1)) were tested. The maximum HLR at which the system showed a high removal efficiency of pollutants and met regulatory standards for reuse in irrigation was 1.07 m(3)m(-2)d(-1), achieving removal efficiencies of biochemical oxygen demand (BOD5) 92%, chemical oxygen demand (COD) 78%, total suspended solids (TSS) 95%, and four log units of fecal coliforms. Electrical conductivity in the effluent ensures that it would not cause soil salinity. Therefore, mesquite wood chips can be considered an innovative material suitable as OFM for BFs treating wastewaters.

  16. Structure of archaeal communities in membrane-bioreactor and submerged-biofilter wastewater treatment plants.

    PubMed

    Gómez-Silván, C; Molina-Muñoz, M; Poyatos, J M; Ramos, A; Hontoria, E; Rodelas, B; González-López, J

    2010-04-01

    A cultivation independent approach (PCR-TGGE) was used to evaluate the occurrence of Archaea in four wastewater treatments based on technologies other than activated sludge, and to comparatively analyze their community structure. TGGE fingerprints (based on partial archaeal 16S-rRNA amplicons) were obtained from sludge samples taken from a pilot-scale aerated MBR fed with urban wastewater and operated under two different sets of conditions (MBR1 and MBR2 treatments), and also from biofilms sampled from two pilot-scale submerged biofilters (SBs) consisting of one aerated and one anoxic column each, fed with urban (USB treatment) or industrial (ISB treatment) wastewater, respectively. Analysis of TGGE fingerprints revealed clear and significant differences of the community structure of Archaea between the wastewater treatments studied, primarily according to wastewater origin and the type of technology. Thirty-two different band classes were detected among the 23 sludge and biofilm samples analyzed, from which five were selected as dominant or distinctive of the four treatments studied. Sixteen predominant TGGE bands were identified, revealing that all of them were related to methanogenic Archaea. Neither other Euryarchaeota groups nor Crenarchaeota members were identified amongst the 16S-rRNA fragments sequenced from separated TGGE bands.

  17. Treatment of gas-phase methanol in conventional biofilters packed with lava rock.

    PubMed

    Prado, Oscar J; Veiga, María C; Kennes, Christian

    2005-06-01

    The performance of laboratory scale methanol-degrading biofilters packed with lava rock was checked during almost 1 yr under different conditions. The biomass concentration and biomass adaptation of the inoculum dramatically affected the start-up and the performance of the systems during the first stages of operation. A fast start-up was obtained when using concentrated and adapted inocula, while diluted or non-adapted inocula proved to be much less efficient. The performance of the reactor during long-term operation was significantly affected by the toxic load and moisture content of the gas. Critical loads between 120 and 280 g/m(3)h were reached during different phases of the study. The reactor had a high stability to EBRT changes when working at values between 48.0 and 91.1s, showing little or no negative effect when decreasing the EBRT. Hardly any difference was observed regarding performance when using either a downflow or upflow feed, although slightly better results were obtained when working in a downflow mode.

  18. Performance evaluation of biofilters and biotrickling filters in odor control of n-butyric acid.

    PubMed

    Ding, Ying; Han, Zhiying; Wu, Weixiang; Shi, Dezhi; Chen, Yingxu; Li, Wenhong

    2011-01-01

    With the rapid development of swine production in China, odor pollution associated with piggery facilities has become an increasing environmental concern. N-butyric acid (n-BA) is one of the key odor compounds selected to represent volatile fatty acids (VFAs) found in piggery facilities. In this study, two biofilters (BFs) packed with compost (BFC) or sludge (BFS) and two biotrickling filters (BTFs) packed with pall rings (BTFP) or multidimensional hollow balls (BTFM), respectively, were compared with regard to their performances in the removal of n-BA. The non-biological removal capacities of packing material of the bioreactors on a per unit volume basis were BFS>BFC>BTFM>BTFP. Maximum biological removal capacities per unit volume of packing material of the bioreactors all exceeded 9.1 kg/m(3)·d and in the order of BFC>BTFM>BFS>BTFP. Kinetic analysis as well as overall evaluation by radar graphs showed that the BTFs achieved superior removal rates to the BFs in the order of BTFM>BTFP>BFC>BFS. The biotrickling filter packed with multidimensional hollow balls could be an effective technology for VFAs removal. Results from this research provide economical and effective alternatives for odor control in piggery facilities.

  19. Removal of chlorinated and non-chlorinated alkanes in a trickle-bed biofilter

    SciTech Connect

    Klasson, K.T.; Davison, B.H.; Barton, J.W.; Jacobs, J.E.

    1998-01-01

    Increasing restrictions in emissions from a variety of industrial settings demand low cost removal of dilute contaminants in air. Many of these contaminants such as volatile organic components (VOCs) and sulfur compounds are biodegradable and can be removed from air streams via biofiltration. The simplest form of biofiltration consists of compost-based systems. More advanced systems designed for unique contaminants are biofilters with bioactive structured packing operating in trickle-bed mode. These advanced systems rely on a microbial consortium capable of degrading the contaminants of concern and the consortium usually is isolated or enriched from a more complex microbial mixture. This paper describes the use of a trickle-bed reactor seeded with a microbial consortium enriched from a methanotrophic culture. The microbial consortium has been found to degrade chlorinated alkanes as the sole carbon source. Degradation rates of alkane mixtures are presented for the trickle-bed as well as results from batch cultures experiments designed to study degradation of various chlorinated and non-chlorinated VOCs.

  20. Predictive mathematical modeling of trickling bed biofilters for elucidating mass transfer and kinetic effects

    SciTech Connect

    Barton, J.W.; Zhang, X.S.; Klasson, K.T.; Davison, B.H.

    1998-03-01

    Mathematical models of varying complexity have been proposed in the open literature for describing uptake of volatile organics in trickling bed biofilters. Many simpler descriptions yield relatively accurate solutions, but are limited as predictive tools by numerous assumptions which decrease the utility of the model. Trickle bed operation on the boundary between mass transfer and kinetic limitation regimes serves as one example in which these models may be insufficient. One-dimensional models may also fail to consider important effects/relationships in multiple directions, limiting their usefulness. This paper discusses the use of a predictive, two-dimensional mathematical model to describe microbial uptake, diffusion through a biofilm, and mass transfer of VOCs from gas to liquid. The model is validated by experimental data collected from operating trickle-bed bioreactors designed for removing sparingly soluble gaseous contaminants. Axial and radial (biofilm) concentration profiles are presented, along with validation results. Operation in regimes in which both mass transfer and kinetic factors play significant roles are discussed, along with predictive modeling implications.

  1. [Removal pathway and influence factors of hydroponic bio-filter method for nitrogen and phosphorus].

    PubMed

    Li, Xian-ning; Song, Hai-liang; Lü, Xi-wu; Osamu, Nishimura; Yuhei, Inamori

    2007-05-01

    Study was made on the use of hydroponic bio-filter method (HBFM) for eutrophic surface water. Results show that HBFM can remove 16.8% of TN and 30.8% of TP at the hydraulic loading rate (HLR) of 3.0 m3/(m2 x d). The removal loading rate of TN and TP can accordingly reach 1.0 and 0.1 g/(m2 x d) respectively. The sedimentation of particulate nitrogen and particulate phosphorus plays a major role in nitrogen and phosphorus removal, and its contribution is 62.2% and 75.9% respectively. The optimal HLR of HBFM ranges from 3.0 to 4.0 m3/(m x d). The intension of secateur for Nasturtium officinale has some effect on its uptake rate, thus the length of cut when harvesting should be less than 10 cm. The harvesting frequency of once a month for Nasturtium officinale has no effect on nitrogen and phosphorus removal of HBFM.

  2. Co-treatment of landfill leachate and domestic wastewater using a submerged aerobic biofilter.

    PubMed

    Ferraz, F M; Povinelli, J; Pozzi, E; Vieira, E M; Trofino, J C

    2014-08-01

    This study used a pilot-scale submerged aerobic biofilter (SAB) to evaluate the co-treatment of domestic wastewater and landfill leachate that was pre-treated by air stripping. The leachate tested volumetric ratios were 0, 2, and 5%. At a hydraulic retention time of 24 h, the SAB was best operated with a volumetric ratio of 2% and removed 98% of the biochemical oxygen demand (BOD), 80% of the chemical oxygen demand (COD) and dissolved organic carbon (DOC), and 90% of the total suspended solids (TSS). A proposed method, which we called the "equivalent in humic acid" (Eq.HA) approach, indicated that the hardly biodegradable organic matter in leachate was removed by partial degradation (71% of DOC Eq.HA removal). Adding leachate at a volumetric ratio of 5%, the concentration of the hardly biodegradable organic matter was decreased primarily as a result of dilution rather than biodegradation, which was confirmed by Fourier transform infrared (FTIR) spectroscopy. The total ammoniacal nitrogen (TAN) was mostly removed (90%) by nitrification, and the SAB performances at the volumetric ratios of 0 and 2% were equal. For the three tested volumetric ratios of leachate (0, 2, and 5%), the concentrations of heavy metals in the treated samples were below the local limits.

  3. Utilization of toxic and vapors as alternate electron acceptors in biofilters

    SciTech Connect

    Lee, B.D.; Apel, W.A.; Walton, M.R.

    1997-08-01

    Conceptually, biofilters are vapor phase bioreactors that rely on microorganisms in the bed medium to oxidize contaminants in off-gases flowing through the bed to less hazardous compounds. In the most studied and utilized systems reduced compounds such as fuel hydrocarbons are enzymatically oxidized to compounds such as carbon dioxide and water. In these types of reactions the microorganisms in the bed oxidize the contaminant and transfer the electrons to oxygen which is the terminal electron acceptor in the process. In essence the contaminant is the carbon and energy source for the microorganisms in the bed medium and through this catabolic process oxygen is reduced to water. An example of this oxidation process can be seen during the degradation of benzene and similar aromatic compounds. Aromatics are initially attacked by a dioxygenase enzyme which oxidizes the compounds to a labile dihydrodiole which is spontaneously converted to a catechol. The dihydroxylated aromatic rings is then opened by oxidative {open_quotes}ortho{close_quotes} or {open_quotes}meta{close_quotes} cleavage yielding cis, cis-muconic acid or 2-hydroxy-cis, cis-muconic semialdehyde, respectively. These organic compounds are further oxidized to carbon dioxide or are assimilated for cellular material. This paper describes the conversion of carbon tetrachloride using methanol as the primary carbon and energy source.

  4. Assoziativspeicher und eine erste Skizze von Konrad Zuse aus dem Jahre 1943

    NASA Astrophysics Data System (ADS)

    Waldschmidt, Klaus

    In dem Beitrag wird eine Handskizze von Konrad Zuse aus dem Jahre 1943 eines assoziativen Speichers in Relaistechnik diskutiert. Die Diskussion ist eingebettet in die Grundlagen des assoziativen Speicherproblems. Zum Schluss des Beitrages werden einige Vorschläge zu MOSRealisierung der Zuse-Schaltung unterbreitet.

  5. Bifurkationsanalyse eines LC Tank VCOs unter Berücksichtigung der variablen Kapazität

    NASA Astrophysics Data System (ADS)

    Bremer, J.-K.; Zorn, C.; Mathis, W.

    2009-05-01

    In dieser Arbeit präsentieren wir einen neuartigen Ansatz für den systematischen Entwurf von integrierten LC Tank VCO-Schaltungen basierend auf dem Andronov Hopf Theorem und der Störungstheorie. Der Ansatz ermöglicht es, eine Abschätzung des resultierenden Abstimmbereichs, eine Stabilitätsanalyse und eine Berechnung der Amplitude des VCOs im Vorfeld des eigentlichen Entwurfs durchzuführen. Des Weiteren erlaubt die vorgestellte Methode eine Optimierung des VCOs hinsichtlich der in den Spezifikationen geforderte Amplitude und eine Minimierung der höheren Harmonischen. Mit Hilfe eines ladungsbasierten MOS-Modells ist es möglich die spannungsabhängige Kapazität der Varaktortransistoren durch einen analytischen Ausdruck zu beschreiben. Auf Basis dieses analytischen Ausdrucks wird die amplitudenabhängige Großsignalkapazität des VCOs in Abhängigkeit von Designparametern und der Tuningspannung modelliert. Die Gültigkeit der vorgestellte Entwurfsmethode wird anhand eines Beispielentwurfes eines 2.4 GHz VCO unter Verwendung einer 0.25 μm HF-CMOS Technologie verifiziert.

  6. Indoor-biofilter growth and exposure to airborne chemicals drive similar changes in plant root bacterial communities.

    PubMed

    Russell, Jacob A; Hu, Yi; Chau, Linh; Pauliushchyk, Margarita; Anastopoulos, Ioannis; Anandan, Shivanthi; Waring, Michael S

    2014-08-01

    Due to the long durations spent inside by many humans, indoor air quality has become a growing concern. Biofiltration has emerged as a potential mechanism to clean indoor air of harmful volatile organic compounds (VOCs), which are typically found at concentrations higher indoors than outdoors. Root-associated microbes are thought to drive the functioning of plant-based biofilters, or biowalls, converting VOCs into biomass, energy, and carbon dioxide, but little is known about the root microbial communities of such artificially grown plants, how or whether they differ from those of plants grown in soil, and whether any changes in composition are driven by VOCs. In this study, we investigated how bacterial communities on biofilter plant roots change over time and in response to VOC exposure. Through 16S rRNA amplicon sequencing, we compared root bacterial communities from soil-grown plants with those from two biowalls, while also comparing communities from roots exposed to clean versus VOC-laden air in a laboratory biofiltration system. The results showed differences in bacterial communities between soil-grown and biowall-grown plants and between bacterial communities from plant roots exposed to clean air and those from VOC-exposed plant roots. Both biowall-grown and VOC-exposed roots harbored enriched levels of bacteria from the genus Hyphomicrobium. Given their known capacities to break down aromatic and halogenated compounds, we hypothesize that these bacteria are important VOC degraders. While different strains of Hyphomicrobium proliferated in the two studied biowalls and our lab experiment, strains were shared across plant species, suggesting that a wide range of ornamental houseplants harbor similar microbes of potential use in living biofilters.

  7. Indoor-Biofilter Growth and Exposure to Airborne Chemicals Drive Similar Changes in Plant Root Bacterial Communities

    PubMed Central

    Hu, Yi; Chau, Linh; Pauliushchyk, Margarita; Anastopoulos, Ioannis; Anandan, Shivanthi; Waring, Michael S.

    2014-01-01

    Due to the long durations spent inside by many humans, indoor air quality has become a growing concern. Biofiltration has emerged as a potential mechanism to clean indoor air of harmful volatile organic compounds (VOCs), which are typically found at concentrations higher indoors than outdoors. Root-associated microbes are thought to drive the functioning of plant-based biofilters, or biowalls, converting VOCs into biomass, energy, and carbon dioxide, but little is known about the root microbial communities of such artificially grown plants, how or whether they differ from those of plants grown in soil, and whether any changes in composition are driven by VOCs. In this study, we investigated how bacterial communities on biofilter plant roots change over time and in response to VOC exposure. Through 16S rRNA amplicon sequencing, we compared root bacterial communities from soil-grown plants with those from two biowalls, while also comparing communities from roots exposed to clean versus VOC-laden air in a laboratory biofiltration system. The results showed differences in bacterial communities between soil-grown and biowall-grown plants and between bacterial communities from plant roots exposed to clean air and those from VOC-exposed plant roots. Both biowall-grown and VOC-exposed roots harbored enriched levels of bacteria from the genus Hyphomicrobium. Given their known capacities to break down aromatic and halogenated compounds, we hypothesize that these bacteria are important VOC degraders. While different strains of Hyphomicrobium proliferated in the two studied biowalls and our lab experiment, strains were shared across plant species, suggesting that a wide range of ornamental houseplants harbor similar microbes of potential use in living biofilters. PMID:24878602

  8. Molecular cloning and expression analysis of the ethylene insensitive3 (EIN3) gene in cucumber (Cucumis sativus).

    PubMed

    Bie, B B; Pan, J S; He, H L; Yang, X Q; Zhao, J L; Cai, R

    2013-10-07

    The plant gaseous hormone ethylene regulates many aspects of plant growth, development, and responses to the environment. Ethylene insensitive3 (EIN3) is a key transcription factor involved in the ethylene signal transduction pathway. To gain a better understanding of this particular pathway in cucumber, the full-length cDNA encoding EIN3 (designated as CsEIN3) was cloned from cucumber for the first time by rapid amplification of cDNA ends. The full length of CsEIN3 was 2560 bp, with an open reading frame of 1908 bp encoding 635 amino acids. Sequence alignment and phylogenetic analyses revealed that CsEIN3 has high homology with other plant EIN3/EIL proteins that were derived from a common ancestor during evolution, and CsEIN3 was grouped into a cluster along with melon. Homology modeling demonstrated that CsEIN3 has a highly similar structure to the specific DNA-binding domain contained in EIN3/EIL proteins. Based on quantitative reverse transcription-polymerase chain reaction analysis, we found that CsEIN3 was constitutively expressed in all organs examined, and was increased during flower development and maturation in both male and female flowers. Our results suggest that CsEIN3 is involved in processes of flower development. In conclusion, this study will provide the basis for further study on the role of EIN3 in relevant biological processes of cucumber and on the molecular mechanism of the cucumber ethylene signaling pathway.

  9. Performance of a new suspended filler biofilter for removal of nitrogen oxides under thermophilic conditions and microbial community analysis.

    PubMed

    Han, Li; Shaobin, Huang; Zhendong, Wei; Pengfei, Chen; Yongqing, Zhang

    2016-08-15

    A suspended biofilter, as a new bioreactor, was constructed for the removal of nitrogen oxides (NOX) from simulated flue gas under thermophilic conditions. The suspended biofilter could be quickly started up by inoculating the thermophilic denitrifying bacterium Chelatococcus daeguensis TAD1. The NO concentration in the inlet stream ranged from 200mg/m(3) to 2000mg/m(3) during the operation, and inlet loading ranged from 8.2-164g/(m(3)·h). The whole operation period was divided into four phases according to the EBRT. The EBRT of phases I, II, III and IV were 88s (9-43d), 44s (44-61d), 66s (62-79d) and 132s (80-97d), respectively. An average NO removal efficiency of 90% was achieved during the whole operation period, and the elimination capacity increased linearly with the increase in NO inlet loading and the maximum elimination capacity reached 146.9g/(m(3)·h). No clogging was observed, although there was a high biomass concentration in the biofilter bed. The remarkable performance in terms of NO removal could be attributed to the rich bacterial communities. The microbial community structure in the biofilm was investigated by high throughput sequencing analysis (16S rRNA MiSeq sequencing). The experimental results showed that the microbial community structure of the biofilm was very rich in diversity, with the most abundant bacterial class of the Alphaproteobacteria, which accounted for 36.5% of the total bacteria, followed by Gammaproteobacteria (30.7%) and Clostridia (27.5%). It was worthwhile to mention that the dominant species in the suspended biofilter biofilm were all common denitrifying bacteria including Rhizobiales (inoculated microbe), Rhodospirillales, Enterobacteriales and Pseudomonadales, which accounted for 19.4%, 17%, 21.6% and 7%, respectively. The inoculated strain TAD1 belonged to Alphaproteobacteria class. Because high-throughput 16S rRNA gene paired-end sequencing has improved resolution of bacterial community analysis, 16S rRNA gene

  10. Influence of synthetic packing materials on the gas dispersion and biodegradation kinetics in fungal air biofilters.

    PubMed

    Prenafeta-Boldú, Frances X; Illa, Josep; van Groenestijn, Johan W; Flotats, Xavier

    2008-05-01

    The biodegradation of toluene was studied in two lab-scale air biofilters operated in parallel, packed respectively with perlite granules (PEG) and polyurethane foam cubes (PUC) and inoculated with the same toluene-degrading fungus. Differences on the material pore size, from micrometres in PEG to millimetres in PUC, were responsible for distinct biomass growth patterns. A compact biofilm was formed around PEG, being the interstitial spaces progressively filled with biomass. Microbial growth concentrated at the core of PUC and the excess of biomass was washed-off, remaining the gas pressure drop comparatively low. Air dispersion in the bed was characterised by tracer studies and modelled as a series of completely stirred tanks (CSTR). The obtained number of CSTR (n) in the PEG packing increased from 33 to 86 along with the applied gas flow (equivalent to empty bed retention times from 48 to 12 s) and with operation time (up to 6 months). In the PUC bed, n varied between 9 and 13, indicating that a stronger and steadier gas dispersion was achieved. Michaelis-Menten half saturation constant (km) estimates ranged 71-113 mg m(-3), depending on the experimental conditions, but such differences were not significant at a 95% confidence interval. The maximum volumetric elimination rate (rm) varied from 23 to 50 g m(-3) h(-1). Comparison between volumetric and biomass specific biodegradation activities indicated that toluene mass transfer was slower with PEG than with PUC as a consequence of a smaller biofilm surface and to the presence of larger zones of stagnant air.

  11. Equalization characteristics of an upflow sludge blanket-aerated biofilter (USB-AF) system.

    PubMed

    Jun, H B; Park, S M; Park, J K; Lee, S H

    2005-01-01

    Equalization characteristics of the upflow sludge blanket-aerated bio-filter (USB-AF) were investigated with the fluctuated raw domestic sewage. Recycle of nitrified effluent from AF to USB triggered the equalization characteristics of the sludge blanket on both soluble and particulate organic matter. Increment of EPS in sludge blanket by nitrate recycle was detected and removal of turbidity and particulates increased at higher recycle ratios by bio-flocculation. Increased TCOD removal in the USB was due to both denitrification of recycled nitrate and entrapment of the particulate organic matter in sludge blanket. Capture of both soluble and particulate organic matter increased sludge blanket layer in the USB, which improved the reactor performances and reduced the organic load on the subsequent AF. Overall TCOD and SS removal efficiencies were about 98% and 96%, respectively in the USB-AF system. Turbidity in the USB effluent was about 44, 20 and 5.5 NTU, at recycle ratios of 0, 100 and 200%, respectively. Particle counts in the range 2-4 microm in the USB effluent were higher than those in influent without nitrate recycle, while particle counts in the range of 0.5-15 microm in the USB effluent decreased 70% at recycle ratio of 200%. The major constituent of EPS extracted from anaerobic sludge was protein and total EPS increased from 109.1 to 165.7 mg/g-VSS with nitrate recycle of 100%. Removal efficiency and concentration of T-N in the UBS-AF effluent was over 70% and below 16 mg/L, respectively.

  12. Nutrient gradients in a granular activated carbon biofilter drives bacterial community organization and dynamics.

    PubMed

    Boon, Nico; Pycke, Benny F G; Marzorati, Massimo; Hammes, Frederik

    2011-12-01

    The quality of drinking water is ensured by hygienic barriers and filtration steps, such as ozonation and granular activated carbon (GAC) filtration. Apart from adsorption, GAC filtration involves microbial processes that remove biodegradable organic carbon from the ozonated ground or surface water and ensures biological stability of the treated water. In this study, microbial community dynamics in were monitored during the start-up and maturation of an undisturbed pilot-scale GAC filter at 4 depths (10, 45, 80 and 115 cm) over a period of 6 months. New ecological tools, based on 16S rRNA gene-DGGE, were correlated to filter performance and microbial activity and showed that the microbial gradients developing in the filter was of importance. At 10 cm from the top, receiving the freshly ozonated water with the highest concentration of nutrients, the microbial community dynamics were minimal and the species richness remained low. However, the GAC samples at 80-115 cm showed a 2-3 times higher species richness than the 10-45 cm samples. The highest biomass densities were observed at 45-80 cm, which corresponded with maximum removal of dissolved and assimilable organic carbon. Furthermore, the start-up period was clearly distinguishable using the Lorenz analysis, as after 80 days, the microbial community shifted to an apparent steady-state condition with increased evenness. This study showed that GAC biofilter performance is not necessarily correlated to biomass concentration, but rather that an elevated functionality can be the result of increased microbial community richness, evenness and dynamics. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Peat and coconut fiber as biofilters for chromium adsorption from contaminated wastewaters.

    PubMed

    Henryk, Kołoczek; Jarosław, Chwastowski; Witold, Żukowski

    2016-01-01

    Batch adsorption experiments were performed for the removal of chromium (III) and chromium (VI) ions from aqueous solutions using Canadian peat and coconut fiber. The Langmuir model was used to describe the adsorption isotherm. The maximum adsorption for peat reached 18.75 mg/g for Cr(III) and 8.02 mg/g for Cr(VI), whereas the value for fiber was slightly higher and reached 19.21 mg/g for Cr(III) and 9.54 mg/g for Cr(VI). Both chromium forms could be easily eluted from the materials. The adsorption of chromium forms to organic matter could be explained in terms of formation of donor-acceptor chemical covalent bound with hydroxyl groups as ligands and chromium as the central atom in the formed complex. The chromate-reducing activities were monitored with the use of electron paramagnetic resonance spectroscopy. The results showed that both adsorption and reduction occurred simultaneously and the maximum adsorption capacity of hexavalent chromium being equal to 95% for fiber and 92% for peat was obtained at pH 1.5. The reduction of Cr(VI) in wastewaters began immediately and disappeared after 20 h. Both materials contained yeast and fungi species which can be responsible for reduction of chromium compounds, due to their enzymatic activity (Chwastowski and Koloczek (Acta Biochim Pol 60: 829-834, 2013)). The reduction of Cr(VI) is a two-phase process, the first phase being rapid and based on chemical reaction and the second phase having biological features. After the recovery step, both types of organic materials can be used again for chromium adsorption without any loss in the metal uptake. Both of the materials could be used as biofilters in the wastewater treatment plants.

  14. Distribution and genetic diversity of the microorganisms in the biofilter for the simultaneous removal of arsenic, iron and manganese from simulated groundwater.

    PubMed

    Yang, Liu; Li, Xiangkun; Chu, Zhaorui; Ren, Yuhui; Zhang, Jie

    2014-03-01

    A biofilter was developed in this study, which showed an excellent performance with the simultaneous removal of AsIII from 150 to 10mg L(-1) during biological iron and manganese oxidation. The distribution and genetic diversity of the microorganisms along the depth of the biofilter have been investigated using DGGE. Results suggested that Iron oxidizing bacteria (IOB, such as Gallionella, Leptothrix), Manganese oxidizing bacteria (MnOB, such as Leptothrix, Pseudomonas, Hyphomicrobium, Arthrobacter) and AsIII-oxidizing bacteria (AsOB, such as Alcaligenes, Pseudomonas) are dominant in the biofilter. The spatial distribution of IOB, MnOB and AsOB at different depths of the biofilter determined the removal zone of FeII, MnII and AsIII, which site at the depths of 20, 60 and 60cm, respectively, and the corresponding removal efficiencies were 86%, 84% and 87%, respectively. This process shows great potential to the treatment of groundwater contaminated with iron, manganese and arsenic due to its stable performance and significant cost-savings. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Isolation and characterization of dimethyl sulfide (DMS)-degrading bacteria from soil and biofilter treating waste gas containing DMS from the laboratory and pulp and paper industry.

    PubMed

    Giri, Balendu Shekher; Juwarkar, Asha A; Satpute, D B; Mudliar, S N; Pandey, R A

    2012-07-01

    Dimethyl sulfide (DMS) is one of the sulfurous pollutants present in the waste gas generated from the pulp and paper industry. DMS has environmental health implications; therefore, it is necessary to treat the waste gas containing DMS prior to discharge into the environment. A bench-scale biofilter was operated in the laboratory as well as in a pulp and paper industry for the treatment of DMS. Both the biofilters were packed with pre-sterilized wood chips and cow dung/compost of the same origin seeded with biomass developed from garden soil enriched with DMS. The biofilters were operated for the generation of process parameters, and the potential microorganisms isolated from both the biofilters have been purified and characterized for degradation of DMS. Further, these cultures were purified on a basal medium using DMS as a sole carbon source for the growth. Further, the purified cultures were characterized through standard fatty acid methyl esters (FAME)-gas chromatography method, and the isolates were found to be mesophilic, aerobic microbes. These microbes were identified as Bacillus sphaericus-GC subgroup F, Paenibacillus polymyxa, B. sphaericus-GC subgroup F, B. sphaericus-GC subgroup F, and Bacillus megaterium-GC subgroup A, respectively. The potential culture for degradation of DMS was identified as B. sphaericus by 16s rRNA molecular analysis.

  16. Comparative investigation on integrated vertical-flow biofilters applying sulfur-based and pyrite-based autotrophic denitrification for domestic wastewater treatment.

    PubMed

    Kong, Zhe; Li, Lu; Feng, Chuanping; Dong, Shanshan; Chen, Nan

    2016-07-01

    Two parallel biofilters applying sulfur/pyrite-based autotrophic denitrification were investigated for removing COD, TP and TN by a coordinated process. Results demonstrated good performance by removing 86.32% vs 87.14% COD and 92.56% vs 89.65% NH4(+)-N. Biofilter with sulfur (BS) was superior on nitrate (89.74% vs 80.72%) and TN removal (83.18% vs 70.42%) while biofilter with pyrite (BP) was better on TP removal (82.58% vs 77.40%) and maintaining sulfate (27.56mgL(-1) vs 41.55mgL(-1)) and pH (7.13 vs 6.31). Water-permeable adsorbents lowered clogging risk and buffered loading. Clone library revealed reasons of diversities, pH variation and sulfate accumulation of both biofilters. Sulfur was efficient on denitrification but whose byproducts were troublesome, pyrite produced less byproduct but which was sensitive to organics. This research was the first attempt to systematically compare two promising alternatives and their merits/demerits for rural wastewater on-site treatment.

  17. Biodegradation studies and sequencing of microcystin-LR degrading bacteria isolated from a drinking water biofilter and a fresh water lake.

    PubMed

    Eleuterio, Lazaro; Batista, Jacimaria R

    2010-07-01

    The presence of microcystin-LR -degrading bacteria in an active anthracite biofilter and in Lake Mead, Nevada was investigated. Four bacterial isolates from enrichment culture were identified using 16S rRNA analysis. Microcystin biodegradation tests were performed with both, the enrichment cultures and the respective isolates, using microcystin alone and acetate as carbon sources. A newly recognized microcystin-degrading bacterium, Morganella morganii, was isolated from the biofilter and from Lake Mead. The results of the biodegradation tests indicated that addition of a carbon source (acetate), significantly repressed the degradation of microcystin-LR. The findings of this study inform on the prevalence of microcystin-degrading bacteria in the environment indicating bioaugmentation may not be needed, if biofiltration is used to remove microcystin from waters. The results also imply that, in a biofilter, biodegradable naturally organic matter (NOM) and microcystin will compete and therefore lower toxin removals are likely in waters with higher NOM content. The feasibility of removing microcystin by biofiltration depends on the toxin concentration and the concentration of biodegradable carbon sources in the biofilter.

  18. Gas dispersion and immobile gas volume in solid and porous particle biofilter materials at low air flow velocities.

    PubMed

    Sharma, Prabhakar; Poulsen, Tjalfe G

    2010-07-01

    Gas-phase dispersion in granular biofilter materials with a wide range of particle sizes was investigated using atmospheric air and nitrogen as tracer gases. Two types of materials were used: (1) light extended clay aggregates (LECA), consisting of highly porous particles, and (2) gravel, consisting of solid particles. LECA is a commercial material that is used for insulation, as a soil conditioner, and as a carrier material in biofilters for air cleaning. These two materials were selected to have approximately the same particle shape. Column gas transport experiments were conducted for both materials using different mean particle diameters, different particle size ranges, and different gas flow velocities. Measured breakthrough curves were modeled using the advection-dispersion equation modified for mass transfer between mobile and immobile gas phases. The results showed that gas dispersivity increased with increasing mean particle diameter for LECA but was independent of mean particle diameter for gravel. Gas dispersivity also increased with increasing particle size range for both media. Dispersivities in LECA were generally higher than for gravel. The mobile gas content in both materials increased with increasing gas flow velocity but it did not show any strong dependency on mean particle diameter or particle size range. The relative fraction of mobile gas compared with total porosity was highest for gravel and lowest for LECA likely because of its high internal porosity.

  19. Rural Sewage Treatment by using Combined Process of Multi-layer Bio-filter and Constructed Wetland

    NASA Astrophysics Data System (ADS)

    Li, Xudong; Paul, Etienne; Qiu, Jiangping; Roustan, Michel; Wisniewski, Christelle; Mauviot, Patrice

    2010-11-01

    A combined process of multi-layer bio-filter and constructed wetland has been used to treat the rural sewage in eastern China. The capacity of the system was 60 m3/d, the hydraulic loading rate (HLR) of the bio-filter and the constructed wetland was 4.0 m3/(m3ṡd) and 0.50 m3/(m3ṡd), respectively. The system has been operated automatically for 2 years. The results showed that the average concentrations of COD, NH4+-N, TN and TP in the effluent were 58.2, 8.1, 12.1 and 0.9 mg/L with the removal efficiency of 79.2%, 62.8%, 55.1% and 77.1% respectively, which could meet the first grade of Chinese national pollutants discharge standard for municipal wastewater treatment plant (GB 18918-2002). The track studies showed that the organic pollutants were mainly removed in the first 4 layers and the ammonia was mainly removed in the 4th˜6th layers of the filter. It was observed that the COD removal efficiency in the whole system decreased from 84.6% to 73.3% following the sequences of summer, autumn, spring and winter. Comparing with traditional techniques, the combined process could provide a higher nitrogen and phosphorus removal capacity.

  20. Application of light-weight filtration media in an anoxic biofilter for nitrate removal from micro-polluted surface water.

    PubMed

    Wang, Zheng; Fei, Xiang; He, Shengbing; Huang, Jungchen; Zhou, Weili

    The research investigated nitrate removal from micro-polluted surface water by the single-stage process of anoxic biofilter using light-weight polystyrene beads as filtration media. In this study, sodium acetate was used as an external carbon source and the nitrate removal efficiency under different regimes of hydraulic loading rate (HLR), water temperature, and C/N ratio was studied. In addition, the effect of backwash on denitrification efficiency was investigated. The results show that the biofilter achieved a high nitrate removal efficiency in 2 weeks at water temperatures ranging between 22 and 25 °C at a C/N ratio (COD:NO3(-)-N) of 6:1. Besides, the average removal efficiency of nitrate at HLRs of 5.66, 7.07 and 8.49 m(3) m(-2) h(-1) were 87.5, 87.3 and 87.1%, respectively. The average removal efficiency of nitrate nitrogen was 13.9% at a HLR of 5.66 m(3) m(-2) h(-1) at water temperatures of 12-14 °C, then it increased to 93.7% when the C/N ratio increased to 10. It suggests that the optimal hydraulic retention time is at water temperatures of 8-10 °C. The water consumption rate of backwash was about 0.2-0.3%, and denitrification efficiency returned to the normal level in 12 h after backwash.

  1. A novel anoxic-aerobic biofilter process using new composite packing material for the treatment of rural domestic wastewater.

    PubMed

    Pan, L T; Han, Y

    2016-01-01

    A pilot scale experiment was conducted to evaluate the characteristics of contaminants removal in a continuously two-stage biological process composed of an anoxic biofilter (AF) and an biological aerated filter (BAF). This novel process was developed by introducing new composite packing material (MZF) into bioreactors to treat rural domestic wastewater. A comparative study conducted by the same process with ceramsite as packing material under the same conditions showed that a MZF system with a Fe proportion in the packing material performed better in chemical oxygen demand (COD) removal (average 91.5%), ammonia (NH4(+)-N) removal (average 98.3%), total nitrogen (TN) removal (average 64.8%) and total phosphorus (TP) removal (average 90%). After treatment of the MZF system, the concentrations of COD, NH4(+)-N, TN and TP in effluent were 20.3 mg/L, 0.5 mg/L, 11.5 mg/L and 0.3 mg/L, respectively. The simultaneously high efficiencies of nitrification, denitrification and phosphorus removal were achieved by the coupling effects of biological and chemical processes in the MZF system. The results of this study showed that the application of MZF might be a favorable choice as packing material in biofilters for treatment of rural domestic wastewater.

  2. Biodegradation of methyl tert-butyl ether by cometabolism with hexane in biofilters inoculated with Pseudomonas aeruginosa.

    PubMed

    Salazar, Margarita; Morales, Marcia; Revah, Sergio

    2012-01-01

    Biodegradation of methyl tert-butyl ether (MTBE) vapors by cometabolism with gaseous hexane (n-hexane > 95%) was investigated using Pseudomonas aeruginosa utilizing short chain aliphatic hydrocarbon (C(5)-C(8)). Kinetic batch experiments showed that MTBE was degraded even when hexane was completely exhausted with a cometabolic coefficient of 1.06 ± 0.16 mg MTBE mg hexane(-1). Intermediate tert-butyl alcohol (TBA) accumulation was observed followed by its gradual consumption. A maximum MTBE elimination capacity (EC(MAX)) of 35 g m(-3) h(-1) and removal efficiency (RE) of 70% were attained in mineral medium amended biofilters having an empty bed residence time (EBRT) of 1 min. For these experimental conditions, a maximum hexane EC of approximately 60 g m(-3) h(-1) was obtained at a load of 75 g m(-3) h(-1). Experiments under transient conditions revealed a competitive substrate interaction between MTBE and hexane. Biomass densities between 5.8 and 12.6 g L(biofilter) (-1) were obtained. Nevertheless, production of biopolymers caused non-uniform distribution flow rates that reduced the performance. Residence time distribution profiles showed an intermediate dispersion flow rate with a dispersion coefficient of 0.8 cm(2) s(-1).

  3. Remediation of nitrate-contaminated wastewater using denitrification biofilters with straws of ornamental flowers added as carbon source.

    PubMed

    Chang, Junjun; Ma, Luyao; Zhou, Yuanyang; Zhang, Shenghua; Wang, Weilu

    Straws of four ornamental flowers (carnation, rose, lily, and violet) were added into denitrification biofilters using gravel as matrix through vertically installed perforated polyvinylchloride pipes to provide organic carbon for the treatment of nitrate-contaminated wastewater operating in batch mode. Removal efficiencies of nitrate and phosphate, as well as temporal variations of nitrogen and carbon during batches 10 and 19, were investigated and assessed. Nitrate removal was efficiently enhanced by the addition of flower straws, but decreased gradually as the organic substances were consumed. Phosphate removal was also improved, although this very limited. High nitrate removal rates were achieved during the initial 12 h in the two batches each lasting for 3 days, along with the depletion of influent dissolved oxygen due to aerobic degradation of the organic compounds. NO2(-)-N of 0.01-2.83 mg/L and NH4(+)-N of 0.02-1.69 mg/L were formed and both positively correlated to the nitrate reduced. Inorganic carbon (IC) concentrations increased during the batches and varied conversely with the nitrate contents, and could be indicative of nitrate removal due to the highly significant positive correlation between NO3(-)-N removed and IC concentration (r(2) = 0.881, p < 0.0001). It is feasible and economical to use the denitrification biofilter to treat nitrate-contaminated wastewater, although further optimization of carbon source addition is still required.

  4. High-load domestic wastewater treatment using a combined anaerobic-aerobic bio-filter with coal cinder as medium.

    PubMed

    Liu, Yaoxing; Lei, Yuxin; Xi, Yin; Liao, Zaiyi; Zhang, Xia

    2017-03-13

    A combined anaerobic-aerobic bio-filter technology was used for field treatment of high-organic-load domestic wastewater with coal cinder as the bio-filter medium. The effects of parameters, including hydraulic retention time (HRT) and backflow ratio, on the decrease in the chemical oxygen demand (COD), NH3-N, total nitrogen (TN), total phosphorus (TP), and turbidity were investigated. The results showed the obvious influence of the HRT and ratio of backflow on wastewater treatment. Under the optimal HRT condition of 18 h, the removal efficiencies of COD, NH3-N, TN, TP, and turbidity were 67.9%, 95.6%, 30.4%, 65.6%, and 83.8%, respectively. When the backflow ratio (2:1) was added to the treatment system, the TN removal obviously increased, and the removal efficiencies of COD, NH3-N, TN, TP, and turbidity were 88.1%, 91.7%, 69.9%, 69.6%, and 97.5%, respectively. These results indicated that the combined technology has the potential as a treatment method for high-organic-load domestic wastewater.

  5. Biodegradation of BTEX in a fungal biofilter: influence of operational parameters, effect of shock-loads and substrate stratification.

    PubMed

    Rene, Eldon R; Mohammad, Balsam T; Veiga, María C; Kennes, Christian

    2012-07-01

    The effect of relative humidity (RH: 30% to >95%) of a gas-phase mixture composed of benzene, toluene, ethylbenzene and para-, meta- and ortho-xylenes (BTEX), inlet concentrations (0.2-12.6 g m(-3)), and empty bed residence times (EBRTs) (48-144 s) was tested in a fungi-dominant biofilter. A maximum elimination capacity (EC(max)) of 244.2 gBTEX m(-3) h(-1) was achieved at a total inlet loading rate (ILR(T)) of 371.2 gBTEXm(-3) h(-1) (RH: 65%). The transient-state response was tested by increasing the ILR(T), in two steps, from ~50 to 850 gm(-3) h(-1) and from ~50 to 320 g m(-3) h(-1), at a constant EBRT of 41.7s. Increasing the ILR(T) reduced the total BTEX removal efficiency (RE(T)) from >97% to 35%, and from >90% to 60% during medium and high shock-load, respectively. When subjected to short (4d) and long-term (7d) shut-down periods, the biofilter was able to recover high EC(max) of, respectively, 200 and 72 gBTEX m(-)3 h(-1) after resuming operation.

  6. Influences of hydraulic loading rate on SVOC removal and microbial community structure in drinking water treatment biofilters.

    PubMed

    Zhang, Xu-Xiang; Zhang, Zong-Yao; Ma, Li-Ping; Liu, Ning; Wu, Bing; Zhang, Yan; Li, Ai-Min; Cheng, Shu-Pei

    2010-06-15

    Six biofilters were used for advanced treatment of Yangtze River source water to investigate the effects of hydraulic loading rate (HLR) on pollutant removal and microbial community. HLR was found to exert significant influences on the removal efficiency of the conventional pollutants and 24 detectable semivolatile organic compounds (SVOCs). More than 85% of chemical oxygen demand and assimilable organic carbon was removed at the optimal HLR of 3.0 m h(-1). With the increase of HLR, SVOC removal showed a decreasing trend. Di-n-butyl phthalate and bis(2-ethylhexyl)phthalate, two main SVOCs in the source water, had the highest removals of 71.2% and 84.4%, respectively. Nearly 65% of 2,6-dinitrotoluene and 80% of isophorone were removed at the lowest HLR. Phylogenetic analysis showed that Escherichia coli, Shigella sp., E. fergusonii and Firmicutes bacteria predominated in the bioreactors. The dominance of E. coli in the low-HLR biofilters might contribute greatly to the high SVOC removal.

  7. Spatial distribution of microorganisms and measurements of oxygen uptake rate and ammonia uptake rate activity in a drinking water biofilter.

    PubMed

    Madoni, P; Davoli, D; Fontani, N; Cucchi, A; Rossi, F

    2001-04-01

    The biofilm characteristics (population dynamics and biofilm composition) in a biological filter for the removal of iron, manganese and ammonium were studied in a drinking water treatment plant. The objective was to examine the spatial distribution and biological composition of active biomass that grows in a biological filter and to verify the effect of the backwashing on the quantity of fixed biomass and on the density and activity of the biological population. Heterotrophic microorganisms activity was higher in the upper layer of the filter. Nitrifying microorganisms colonized the biofilter in a stratified manner and their activity was higher in the second layer of the filter. A total of 14 species of ciliated protozoa and 7 species of filamentous microorganisms were found in the biofilters. Ciliates were concentrated in the filterbed layer in which the heterotrophic activity was higher. The grazing activity of ciliates on heterotrophic bacteria reduced the competition pressure on nitrifying microorganisms, supporting their growth and thus raising the ammonium removal efficiency. In general, filamentous microorganisms appeared to be indifferent to operating changes in the plant such as backwashing and filtering cycles. Crenothrix was the prevalent filamentous microorganism in terms of both frequency and abundance; it was found prevalently in the first layer where the oxidisation of iron and manganese occurred.

  8. Organic Carbon Amendments for Enhanced Biological Attenuation of Trace Organic Contaminants in Biochar-Amended Stormwater Biofilters.

    PubMed

    Ulrich, Bridget A; Vignola, Marta; Edgehouse, Katelynn; Werner, David; Higgins, Christopher P

    2017-08-15

    This study sought to evaluate how dissolved organic carbon (DOC) affects attenuation of trace organic contaminants (TOrCs) in biochar-amended stormwater biofilters. It was hypothesized that (1) DOC-augmented runoff would demonstrate enhanced TOrC biodegradation and (2) biochar-amended sand bearing DOC-cultivated biofilms would achieve enhanced TOrC attenuation due to sorptive retention and biodegradation. Microcosm and column experiments were conducted utilizing actual runoff, DOC from straw and compost, and a suite of TOrCs. Biodegradation of TOrCs in runoff was more enhanced by compost DOC than straw DOC (particularly for atrazine, prometon, benzotriazole, and fipronil). 16S rRNA gene quantification and sequencing revealed that growth-induced microbial community changes were, among replicates, most consistent for compost-augmented microcosms and least consistent for raw runoff microcosms. Compost DOC most robustly enhanced utilization of TOrCs as carbon substrates, possibly due to higher residual nutrient levels upon TOrC exposure. Sand columns containing just 0.5 wt % biochar maintained sorptive TOrC retention in the presence of compost-DOC-cultivated biofilms, and TOrC removal was further enhanced by biological activity. Overall, these results suggest that coamendment with biochar and compost may robustly enhance TOrC attenuation in stormwater biofilters, a finding of significance for efforts to mitigate the impacts of runoff on water quality.

  9. Development and calibration of a nitrification PDE model based on experimental data issued from biofilter treating drinking water.

    PubMed

    Queinnec, I; Ochoa, J C; Wouwer, A Vande; Paul, E

    2006-06-05

    To remove ammonia for production of drinking water, nitrification can be performed in a bio-filter. At least 1 month is necessary to capture from the groundwater and then grow a sufficient amount of nitrifying bacteria to reach the desired removal efficiency. Improving start-up of bio-filters at low substrate concentration is therefore a major challenge. In this connection, it is important to develop appropriate models for designing, monitoring or analysing biofilm systems during start-up or following disinfection events. This study discusses the development and calibration of a nitrification PDE model which reflects the compromise between the complexity associated with the description of the full physical and biochemical mechanisms and the search for a simplified model with identifiable parameters. This model takes only the relevant phenomena (considering the full operating range) into account. The validity of the calibrated model has been evaluated through experiments under very different operational conditions, at the laboratory and under real industrial conditions, involving the full upstream chain of water treatment (iron oxidation and sand filter). Copyright 2006 Wiley Periodicals, Inc.

  10. Enhanced nitrogen removal in the combined activated sludge-biofilter system of the Southpest Wastewater Treatment Plant.

    PubMed

    Jobbágy, A; Tardy, G M; Literáthy, B

    2004-01-01

    In 1999 the existing activated sludge unit of the Southpest Wastewater Treatment Plant was supplemented by a two-stage biofilter system aiming for nitrification and post-denitrification. In this arrangement excess biomass of the filters is wasted through the activated sludge unit, facilitating backseeding, and recirculation of the nitrate-rich effluent of the N-filter serves for decreasing the methanol demand of the DN-filter and for saving aeration energy at the same time. The paper reports on the development of an ASM1-based mathematical model that proved to be adequate for describing the interactions in the combined system and was used to compare the efficiency of different treatment options. Full-scale results verified that backseeding may considerably improve performance. However, nitrification ability of the activated sludge unit depends on the treatment temperature and, if unexpected, can be limited by insufficient oxygen supply. The upgrading possibilities outlined may serve as a new perspective for implementation of combined activated sludge-biofilter systems.

  11. Evaluation of the bioremoval of Cr(VI) and TOC in biofilters under continuous operation using response surface methodology.

    PubMed

    Leles, Daniela M A; Lemos, Diego A; Filho, Ubirajara C; Romanielo, Lucienne L; de Resende, Miriam M; Cardoso, Vicelma L

    2012-06-01

    In the present study, the bioremoval of Cr(VI) and the removal of total organic carbon (TOC) were achieved with a system composed by an anaerobic filter and a submerged biofilter with intermittent aeration using a mixed culture of microorganisms originating from contaminated sludge. In the aforementioned biofilters, the concentrations of chromium, carbon, and nitrogen were optimized according to response surface methodology. The initial concentration of Cr(VI) was 137.35 mg l(-1), and a bioremoval of 85.23% was attained. The optimal conditions for the removal of TOC were 4 to 8 g l(-1) of sodium acetate, >0.8 g l(-1) of ammonium chloride and 60 to 100 mg l(-1) of Cr(VI). The results revealed that ammonium chloride had the strongest effect on the TOC removal, and 120 mg l(-1) of Cr(VI) could be removed after 156 h of operation. Moreover, 100% of the Cr(VI) and the total chromium content of the aerobic reactor output were removed, and TOC removals of 80 and 87% were attained after operating the anaerobic and aerobic reactors for 130 and 142 h, respectively. The concentrations of cells in both reactors remained nearly constant over time. The residence time distribution was obtained to evaluate the flow through the bioreactors.

  12. Analysis of Metabolites and Carbon Balance in the Biofilteration of Cumene Using Loofa Sponge as Biofilter Media.

    PubMed

    Shahi, Amrita; Rai, B N; Singh, R S

    2016-09-01

    A laboratory-scale biofilter study was performed to treat cumene-inoculated mixed culture of bacterial community and loofa sponge (Luffa cylindrica) as support media for a period of 120 days in five distinct phases. The removal efficiency was obtained in the range of 40-85 % with maximum elimination capacity of 700 g m(-3) h(-1) at the inlet load of 1167 g m(-3) h(-1). The result demonstrated that loofa sponge is good support media for the removal of cumene at higher loading rates. Loofa sponge was characterized via chemical analysis and analytical techniques such as XRD; FTIR; XPS; and CHN, and the result obtained confirms its suitability as biofilter media. The SEM results of loofa with inoculum shows the formation of a biofilm layer on the surface of loofa. The GC-MS analysis of leachate confirms the presence of different organic compounds such as acetaldehyde and 4-hydroxy-2-oxopentanoic acids which are stable metabolites during cumene biodegradation. About 12.69 % of carbon present in inlet cumene was converted to biomass.

  13. Field evaluation of wood bark-based down-flow biofilters for mitigation of odor, ammonia, and hydrogen sulfide emissions from confined swine nursery barns.

    PubMed

    Kafle, Gopi Krishna; Chen, Lide; Neibling, Howard; Brian He, B

    2015-01-01

    Two down-flow wood bark-based biofilters were evaluated for their effectiveness in treating odor, NH3 and H2S under actual swine farm conditions. The water requirement for maintaining proper media moisture contents (MC) under different ventilation rates and intervals were determined. The effect of media depth and MC on the biofilters' performance was also evaluated. The aerodynamic resistance on biofilters was studied using computational fluid dynamics (CFD) software. Water requirements for biofilters were obtained in the range of 3.8-556.0 L/m(3)/d for ventilation duration of 1-24 h/d (depending on the age of the pig and environmental conditions). The highest reductions in odor, NH3 and H2S, obtained in this study at empty bed residence times (EBRT) of 1.6-3.1 s, were 73.5-76.9%, 95.2-97.9% and 95.8-100.0%, respectively. The pressure drop was 28.8-68.8 Pa for a media depth of 381 mm at an EBRT of 1.6-3.1 s and an MC of 64-65%. The pressure drop followed a secondary order polynomial line with both airflow rate and media MC (R(2) = 0.927-0.982). The results of odor, NH3 and H2S reduction efficiency and pressure drop suggest a media depth of ≥254 mm, MC ≥ 35-50% and EBRT of 2-3 s for successful operations of the wood bark-based biofilters. A high correlation was found between the measured and predicted pressured drops obtained using CFD software (R(2) = 0.921, RMSE = 0.145). Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Ein Organic Computing Ansatz zur Steuerung einer sechsbeinigen Laufmaschine

    NASA Astrophysics Data System (ADS)

    Auf, Adam El Sayed; Larionova, Svetlana; Mösch, Florian; Litza, Marek; Jakimovski, Bojan; Maehle, Erik

    Obwohl die Rechengeschwindigkeit von Computern und die Komplexität unserer Systeme ständig zunimmt, sind die heutigen Laufmaschinen nicht in der Lage, sich mit den Fähigkeiten von Landtieren wie zum Beispiel Insekten zu messen. Das Verständnis biologischer Konzepte und das Lernen von der Natur könnten zur Verbesserung der heutigen Maschinen beitragen und sie ein wenig “lebensähnlicher“ machen. Dieser Artikel stellt einen Kontrollarchitekturansatz basierend auf “Organic Computing“-Prinzipien vor, der die Nutzung von Dezentralisierung und Selbstorganisation an einer sechsbeinigen Laufmaschine demonstriert. Die vorliegende Arbeit erklärt die elementaren Mechanismen für das gerade Laufen, das Kurvenlaufen sowie das Drehen auf der Stelle und den Umgang mit strukturellen körperlichen Änderungen wie einer Beinamputation und stellt die Ergebnisse experimenteller Versuche vor.

  15. Evolutionstheorie als Geschichtstheorie - Ein neuer Ansatz historischer Institutionenforschung

    NASA Astrophysics Data System (ADS)

    Patzelt, Werner J.

    Werden und Vergehen kennzeichnen die Natur. Dass Einzelwesen geboren werden, reifen, altern und sterben, lernen schon Kinder. Dass auch Arten, einschließlich der des Menschen, entstehen und vergehen, gerät während der Schulzeit ins Blickfeld. Erwachsene begreifen dann, dass Individuen gleichsam die Träger und "Realisatoren“ des Bauplans einer Art sind: Als solche werden sie gezeugt, als solche tragen sie ihre Art während der eigenen Lebensspanne, als solche geben viele den ihnen eingeschriebenen Bauplan an Nachfolger weiter, und all dies leistend wirken Einzelwesen wie "Durchlaufposten“ ihrer Art. Diese besteht zwar nie ohne ihre Individuen; doch meist kommt es auf kein einzelnes Lebewesen als solches an, um dessen Art fortbestehen zu lassen. Zu verdanken ist der Wandel einer Art mancherlei Veränderungen (z. B. Variationen, Rekombinationen) bei der Weitergabe des Bauplans von Individuum zu Individuum, desgleichen den Besonderheiten einer je konkreten Realisierung des allgemeinen Bauplans einer Art unter spezifischen Umständen. Durchsetzungskraft, weitere Verbreitung und somit Dauerhaftigkeit ("Mutation“) erlangt solcher Wandel dann, wenn die bei der Weitergabe unterlaufenen Veränderungen und die von der Umwelt oder der ökologischen Nische einem Individuum oder einer Gruppe von Individuen aufgezwungenen Variationen ihrerseits Weitergabevorteile bei der Reproduktion des Bauplans eröffnen. Die individueller Veränderung geschuldete Ausnahme mag dann nach einigen Generationen sogar der Normalfall geworden sein. Umwelt ist dabei alles, was ein Individuum oder eine Art umgibt. Die "ökologische Nische“ ist hingegen jener Teil der Umwelt, welcher für das Individuum oder die Art unmittelbar wichtig ist, vor allem weil aus ihr die nötigen Ressourcen bezogen werden oder in ihr die Auseinandersetzung mit Konkurrenten zu bestehen ist.

  16. The Arabidopsis EIN2 restricts organ growth by retarding cell expansion

    PubMed Central

    Feng, Guanping; Liu, Gang; Xiao, Jianhua

    2015-01-01

    The growth of plant organ to its characteristic size is a fundamental developmental process, but the mechanism is still poorly understood. Plant hormones play a great role in organ size control by modulating cell division and/or cell expansion. ETHYLENE INSENSITVE 2 (EIN2) was first identified by a genetic screen for ethylene insensitivity and is regarded as a central component of ethylene signaling, but its role in cell growth has not been reported. Here we demonstrate that changed expression of EIN2 led to abnormity of cell expansion by morphological and cytological analyses of EIN2 loss-of-function mutants and the overexpressing transgenic plant. Our findings suggest that EIN2 controls final organ size by restricting cell expansion. PMID:26039475

  17. Berechnung der auftretenden lokalen Kräfte auf der magnetischen Beschichtung eines magnetischen Rasterkraftmikroskops

    NASA Astrophysics Data System (ADS)

    Preisner, T.; Mathis, W.

    2009-05-01

    Die numerische Berechnung entstehender Kraftwirkungen auf Körper aufgrund magnetischer Wechselwirkungen zwischen diesen, ist in Bezug auf die mechanische Deformation dieser Körper ein noch nicht vollständig gelöstes Problem. In dieser Arbeit wird ein Vergleich vorhandener Kraftberechnungsmethoden hinsichtlich der totalen Kraft anhand eines analytisch berechenbaren Beispiels vorgestellt, sowie Unterschiede der lokalen Kraftdichten dieser Methoden in Anwendung auf die magnetische Beschichtung eines magnetischen Rasterkraftmikroskops aufgezeigt. Due to magnetic interactions between magnetic field inducing bodies, force effects occur on the materials. The numerical computation of those occuring forces with respect to a subsequent structural analysis of a deformable material is still a topic of interest in research. In this paper a comparison between several existent force calculation methods regarding the total force is given for an example with two magnetic cubes. Furthermore, differences are shown concerning the local force densities on the magnetic coating of a magnetic force microscope.

  18. Ein Framework für echtzeitfähige Ethernet-Netzwerke

    NASA Astrophysics Data System (ADS)

    Dopatka, Frank

    Im Rahmen dieser Arbeit wird die Entwicklung eines formalen Framewoks vorgestellt, mit dessen Hilfe zwischen der Kompatibilität zum verbreiteten baumförmigen Standard-Ethernet und der Einhaltung von Echtzeitanforderungen einer automatisierten Anlage variiert werden kann. Damit kann bereits vor der Auswahl einer bestimmten Technologie eine Schedule der Echtzeit-Übertragungen offline kalkuliert und simuliert werden, sobald die Anforderungen der Geräte im industriellen Echtzeit-Netzwerk bekannt sind.

  19. Two distinct EIN2 genes cooperatively regulate ethylene signaling in Lotus japonicus.

    PubMed

    Miyata, Kana; Kawaguchi, Masayoshi; Nakagawa, Tomomi

    2013-09-01

    Leguminous plants establish a mutualistic symbiosis with bacteria, collectively referred to as rhizobia. Host plants positively and negatively regulate the symbiotic processes to keep the symbiosis at an appropriate level. Although the plant hormone ethylene is known as a negative regulator of symbiotic processes, the molecular mechanisms of ethylene signaling remain unresolved, especially in the model plant Lotus japonicus. Here, we identified two genes, LjEIN2-1 and LjEIN2-2, from L. japonicus. These genes share moderate similarity in their amino acid sequences, are located on different chromosomes and are composed of different numbers of exons. Suppression of either LjEIN2-1 or LjEIN2-2 expression significantly promoted the root growth of transformed plants on plates containing 1-amino-cyclopropane-carboxylic acid (ACC), the biosynthetic precursor of ethylene. Simultaneous suppression of both LjEIN2-1 and LjEIN2-2 markedly increased the ethylene insensitivity of transgenic roots and resulted in an increased nodulation phenotype. These results indicate that LjEIN2-1 and LjEIN2-2 concertedly regulate ethylene signaling in L. japonicus. We also observed that Nod factor (NF) induced the expression of the ethylene-responsive gene LjACO2, and simultaneous treatment with NF and ACC markedly increases its transcript level compared with either NF or ACC alone. Because LjACO2 encodes ACC oxidase, which is a key enzyme in ethylene biosynthesis, this result suggests the existence of an NF-triggered negative feedback mechanism through ethylene signaling.

  20. Nitric oxide regulates dark-induced leaf senescence through EIN2 in Arabidopsis.

    PubMed

    Niu, Yun-Han; Guo, Fang-Qing

    2012-08-01

    The nitric oxide (NO)-deficient mutant nos1/noa1 exhibited an early leaf senescence phenotype. ETHYLENE INSENSITIVE 2 (EIN2) was previously reported to function as a positive regulator of ethylene-induced senescence. The aim of this study was to address the question of how NO interacts with ethylene to regulate leaf senescence by characterizing the double mutant ein2-1 nos1/noa1 (Arabidopsis thaliana). Double mutant analysis revealed that the nos1/noa1-mediated, dark-induced early senescence phenotype was suppressed by mutations in EIN2, suggesting that EIN2 is involved in nitric oxide signaling in the regulation of leaf senescence. The results showed that chlorophyll degradation in the double mutant leaves was significantly delayed. In addition, nos1/noa1-mediated impairment in photochemical efficiency and integrity of thylakoid membranes was reverted by EIN2 mutations. The rapid upregulation of the known senescence marker genes in the nos1/noa1 mutant was severely inhibited in the double mutant during leaf senescence. Interestingly, the response of dark-grown nos1/noa1 mutant seedlings to ethylene was similar to that of wild type seedlings. Taken together, our findings suggest that EIN2 is involved in the regulation of early leaf senescence caused by NO deficiency, but NO deficiency caused by NOS1/NOA1 mutations does not affect ethylene signaling. © 2012 Institute of Botany, Chinese Academy of Sciences.

  1. Isolates identification and characteristics of microorganisms in biotrickling filter and biofilter system treating H2S and NH3.

    PubMed

    Guang-Hui, Yu; Xiao-Jun, Xu; Pin-Jing, He

    2007-01-01

    A combination system of biotrickling filter (BTF) and biofilter (BF), adopting surfactant-modified clinoptilolite and surfactant-modified wood chip as the media respectively, was applied to treat H2S and NH3 simultaneously. The identification and sole carbon sources utilization patterns of isolates in the combination system were studied by Biolog system. The isolates were identified as Bacillus sphaericus, Geobacillus themoglucosidasius (55 degrees C) and Micrococcus luteus (ATCC 9341) in BTF, and Aspergillus sydowii (Bainier & Sartory) Thorm & Church in BF. Among 95 substrate classes supplied by Biolog system, the carboxylic acids and methyl esters had the highest utilization extent for the four species, followed by the amino acids and peptides. The descending sequence of carbon sources utilization capability of isolates was A. sydowii (52.6%), M. luteus (39.5%), B. sphaericus (21.6%), and G. thermoglucosidasius (17.7%).

  2. Microbiological removal of hydrogen sulfide from biogas by means of a separate biofilter system: experience with technical operation.

    PubMed

    Schieder, D; Quicker, P; Schneider, R; Winter, H; Prechtl, S; Faulstich, M

    2003-01-01

    The "BIO-Sulfex" biofilter of ATZ-EVUS removes hydrogen sulfide from biogas in a biological way. Hydrogen sulfide causes massive problems during power generation from biogas in a power plant, e.g. corrosion of engines and heat exchangers, and thus causes frequent and therefore expensive engine oil changes. The BIO-Sulfex module is placed between the digester and the power-plant and warrants a cost-effective, reliable and fully biological desulfurization. In the cleaned gas concentrations of less than 100 ppm can be achieved. Power-plant manufacturers usually demand less than 500 or less than 200 ppm. At present, several plants with biogas flow rates between 20 and 350 m3/h are in operation.

  3. Effectiveness of probiotic Phaeobacter bacteria grown in biofilters against Vibrio anguillarum infections in the rearing of Turbot (Psetta maxima) larvae.

    PubMed

    Prol-García, María J; Pintado, José

    2013-12-01

    The rearing environment of first-feeding turbot larvae, usually with high larvae densities and organic matter concentrations, may promote the growth of opportunistic pathogenic Vibrionaceae bacteria, compromising the survival of the larvae. The aim of this study was to assess the effectiveness of the biofilm-forming probiotic Phaeobacter 27-4 strain grown on a ceramic biofilter (probiofilter) in preventing Vibrio anguillarum infections in turbot larvae. In seawater with added microalgae and maintained under turbot larvae rearing conditions, the probiofilter reduced the total Vibrionaceae count and the concentration of V. anguillarum, which was undetectable after 144 h by real-time PCR. The probiofilter also improved the survival of larvae challenged with V. anguillarum, showing an accumulated mortality similar to that of uninfected larvae (35-40 %) and significantly (p < 0.05) lower than that of infected larvae with no probiofilter (76 %) due to a decrease in the pathogen concentration and in total Vibrionaceae. Furthermore, the probiofilter improved seawater quality by decreasing turbidity. Phaeobacter 27-4 released from the probiofilters was able to survive in the seawater for at least 11 days. The bacterial diversity in the larvae, analysed by denaturing gradient gel electrophoresis, was low, as in the live prey (rotifers), and remained unchanged in the presence of V. anguillarum or the probiofilter; however, the probiofilter reduced the bacterial carrying capacity of the seawater in the tanks. Phaeobacter-grown biofilters can constantly inoculate probiotics into rearing tanks and are therefore potentially useful for bacterial control in both open and recirculating industrial units.

  4. Butyric Acid- and Dimethyl Disulfide-Assimilating Microorganisms in a Biofilter Treating Air Emissions from a Livestock Facility▿

    PubMed Central

    Kristiansen, Anja; Lindholst, Sabine; Feilberg, Anders; Nielsen, Per H.; Neufeld, Josh D.; Nielsen, Jeppe L.

    2011-01-01

    Biofiltration has proven an efficient tool for the elimination of volatile organic compounds (VOCs) and ammonia from livestock facilities, thereby reducing nuisance odors and ammonia emissions to the local environment. The active microbial communities comprising these filter biofilms have not been well characterized. In this study, a trickle biofilter treating air from a pig facility was investigated and proved efficient in removing carboxylic acids (>70% reduction), mainly attributed to the primary filter section within which reduced organic sulfur compounds were also depleted (up to 50%). The secondary filter eliminated several aromatic compounds: phenol (81%), p-cresol (89%), 4-ethylphenol (68%), indole (48%), and skatole (69%). The active butyric acid degrading bacterial community of an air filter sample was identified by DNA stable-isotope probing (DNA-SIP) and microautoradiography, combined with fluorescence in situ hybridization (MAR-FISH). The predominant 16S rRNA gene sequences from a clone library derived from “heavy” DNA from [13C4]butyric acid incubations were Microbacterium, Gordonia, Dietzia, Rhodococcus, Propionibacterium, and Janibacter, all from the Actinobacteria. Actinobacteria were confirmed and quantified by MAR-FISH as being the major bacterial phylum assimilating butyric acid along with several Burkholderiales-related Betaproteobacteria. The active bacterial community assimilating dimethyl disulfide (DMDS) was characterized by DNA-SIP and MAR-FISH and found to be associated with the Actinobacteria, along with a few representatives of Flavobacteria and Sphingobacteria. Interestingly, ammonia-oxidizing Betaproteobacteria were also implicated in DMDS degradation, as were fungi. Thus, multiple isotope-based methods provided complementary data, enabling high-resolution identification and quantitative assessments of odor-eliminating Actinobacteria-dominated populations of these biofilter environments. PMID:22003018

  5. Identification of bacteria potentially responsible for oxic and anoxic sulfide oxidation in biofilters of a recirculating mariculture system.

    PubMed

    Cytryn, Eddie; van Rijn, Jaap; Schramm, Andreas; Gieseke, Armin; de Beer, Dirk; Minz, Dror

    2005-10-01

    Bacteria presumably involved in oxygen- or nitrate-dependent sulfide oxidation in the biofilters of a recirculating marine aquaculture system were identified using a new application of reverse transcription-PCR denaturing gradient gel electrophoresis (DGGE) analysis termed differential-transcription (DT)-DGGE. Biofilter samples were incubated in various concentrations of sulfide or thiosulfate (0 to 5 mM) with either oxygen or nitrate as the sole electron acceptor. Before and after short-term incubations (10 to 20 h), total DNA and RNA were extracted, and a 550-bp fragment of the 16S rRNA genes was PCR amplified either directly or after reverse transcription. DGGE analysis of DNA showed no significant change of the original microbial consortia upon incubation. In contrast, DGGE of cDNA revealed several phylotypes whose relative band intensities markedly increased or decreased in response to certain incubation conditions, indicating enhanced or suppressed rRNA transcription and thus implying metabolic activity under these conditions. Specifically, species of the gammaproteobacterial genus Thiomicrospira and phylotypes related to symbiotic sulfide oxidizers could be linked to oxygen-dependent sulfide oxidation, while members of the Rhodobacteraceae (genera Roseobacter, Rhodobacter, and Rhodobium) were putatively active in anoxic, nitrate-dependent sulfide oxidation. For all these organisms, the physiology of their closest cultured relatives matches their DT-DGGE-inferred function. In addition, higher band intensities following exposure to 5 mM sulfide and nitrate were observed for Thauera-, Hydrogenophaga-, and Dethiosulfovibrio-like phylotypes. For these genera, nitrate-dependent sulfide oxidation has not been documented previously and therefore DT-DGGE might indicate a higher relative tolerance to high sulfide concentrations than that of other community members. We anticipate that DT-DGGE will be of general use in tracing functionally equivalent yet

  6. Innovative BI-Lösungen als Basis für eine erfolgreiche Transformation zu Utility 4.0

    NASA Astrophysics Data System (ADS)

    Phillipp, Daniel; Ebert, Sebastian

    Für eine erfolgreiche Transformation, vom reinen Energieversorger hin zum Energiedienstleister, werden innovative Business-Intelligence-Lösungen notwendig sein und eine zentrale Rolle einnehmen. Dabei ist es zunächst essenziell, die Herausforderungen zu kennen und ihnen mit geeigneten Analysen zu begegnen. Die Basis hierzu bildet eine abgestimmte und auf die strategischen Unternehmensziele ausgerichtete Architektur und Vorgehensweise. Zwei Beispiele veranschaulichen, wie ein gesamtheitlicher Ansatz, auch bei Datenvielfalt und hoher Komplexität, operative Prozesse optimiert, und fortgeschrittene Analysen zukünftig einen Beitrag zum Unternehmenserfolg liefern können.

  7. Prediction of coexistent carcinomas risks by subjective EIN diagnosis and comparison with WHO classification in endometrial hyperplasias.

    PubMed

    Yang, Yu-Feng; Liao, Ying-Yang; Peng, Ning-Fu; Li, Le-Qun; Xie, Shu-Rui; Wang, Run-Bang

    2012-12-15

    Endometrial intraepithelial neoplasia (EIN) classification is proposed as a new diagnostic system to resolve the limitations of the World Health Organization (WHO) classification in routine practice. Our aim was to find out whether EIN classification excels the WHO classification regarding the accurate prediction of coexisting endometrial carcinomas (EC) in biopsy specimens. We retrospectively re-classified 139 WHO-classified endometrial hyperplasia (EH) cases by subjective EIN diagnosis and compared the incidence of coexisting carcinomas using two classification systems by re-evaluating biopsy and corresponding hysterectomy specimens. Of 139 WHO-classified hyperplasia cases, 36 and 103 were classified as benign and EIN cases, respectively. Forty of 93 cases with atypical EH had EC at hysterectomy as compared with 2/46 cases without atypical EH, while EC was detected in 42/103 cases with EIN, and in 0 of 36 cases without EIN. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for atypical EH vs. non-atypical EH in biopsy specimen was 95.2%, 45.4%, 43.0% and 95.7%, respectively. For EIN vs. benign, the sensitivity was 100% and the specificity was 37.1%. The incidence of coexisting carcinomas in EIN cases was similar to that in atypical EH cases. However, regarding the exclusion of coexisting carcinomas, EIN criteria of benign lesions excelled the WHO criteria of non-atypical EH/CH.

  8. Effect of extended and daily short-term starvation/shut-down events on the performance of a biofilter treating toluene vapors.

    PubMed

    Jiménez, Lucero; Arriaga, Sonia; Muñoz, Raúl; Aizpuru, Aitor

    2017-12-01

    Industrial emissions of Volatile Organic Compounds are usually discontinuous. To assess the impact of interruptions in pollutant supply on the performance of biological treatment systems, two identical biofilters previously operated under continuous toluene loadings were subjected for 110 days to extended (12, 24, 36, 48, 60, 72, 84 and 96 h) and for a week to daily (8 h on, 16 h off) toluene starvation/shutdown events. One biofilter was operated under complete shutdowns (both air and toluene supply were interrupted), while the other maintained the air supply under toluene starvation. The biofilter operated under complete shutdowns was able to withstand both the extended and daily pollutant interruptions, while starvation periods >24 h severely impacted the performance of the other biofilter, with a removal efficiency decrease from 97.7 ± 0.1% to 45.4 ± 6.7% at the end of the extended starvation periods. This deterioration was likely due to a reduction in liquid lixiviation (from a total volume of 2380 mL to 1800 mL) mediated by the countercurrent airflow during the starvation periods. The presence of air under toluene starvation also favored the accumulation of inactive biomass, thus increasing the pressure drop from 337 to 700 mm H2O.m(-1), while decreasing the wash out of acidic by-products with a significantly higher pH of leachates (Student paired t-test <0.05). This study confirmed the need to prevent the accumulation of inhibitory compounds produced during process perturbation in order to increase biofiltration robustness. Process operation with sufficient drainage in the packing material and the absence of countercurrent airflow are highly recommended during toluene deprivation periods. Copyright © 2017. Published by Elsevier Ltd.

  9. Back Propagation Neural Network Model for Predicting the Performance of Immobilized Cell Biofilters Handling Gas-Phase Hydrogen Sulphide and Ammonia

    PubMed Central

    Rene, Eldon R.; López, M. Estefanía; Kim, Jung Hoon; Park, Hung Suck

    2013-01-01

    Lab scale studies were conducted to evaluate the performance of two simultaneously operated immobilized cell biofilters (ICBs) for removing hydrogen sulphide (H2S) and ammonia (NH3) from gas phase. The removal efficiencies (REs) of the biofilter treating H2S varied from 50 to 100% at inlet loading rates (ILRs) varying up to 13 g H2S/m3 ·h, while the NH3 biofilter showed REs ranging from 60 to 100% at ILRs varying between 0.5 and 5.5 g NH3/m3 ·h. An application of the back propagation neural network (BPNN) to predict the performance parameter, namely, RE (%) using this experimental data is presented in this paper. The input parameters to the network were unit flow (per min) and inlet concentrations (ppmv), respectively. The accuracy of BPNN-based model predictions were evaluated by providing the trained network topology with a test dataset and also by calculating the regression coefficient (R 2) values. The results from this predictive modeling work showed that BPNNs were able to predict the RE of both the ICBs efficiently. PMID:24307999

  10. Effects of concentration and gas flow rate on the removal of gas-phase toluene and xylene mixture in a compost biofilter.

    PubMed

    Rene, Eldon R; Sergienko, Natalia; Goswami, Torsha; López, M Estefanía; Kumar, Gopalakrishnan; Saratale, Ganesh D; Venkatachalam, Perumal; Pakshirajan, K; Swaminathan, T

    2017-08-09

    The aim of this work was to study the performance of a compost/ceramic bead biofilter (6:4 v/v) for the removal of gas-phase toluene and xylene at different inlet loading rates (ILR). The inlet toluene (or) xylene concentrations were varied from 0.1 to 1.5gm(-3), at gas flow rates of 0.024, 0.048 and 0.072m(3)h(-1), respectively, corresponding to total ILR varying between 7 and 213gm(-3)h(-1). Although there was mutual inhibition, xylene removal was severely inhibited by the presence of toluene than toluene removal by the presence of xylene. The biofilter was also exposed to transient variations such as prolonged periods of shutdown (30days) and shock loads to envisage the response and recuperating ability of the biofilter. The maximum elimination capacity (EC) for toluene and xylene were 29.2 and 16.4gm(-3)h(-1), respectively, at inlet loads of 53.8 and 43.7gm(-3)h(-1). Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Datenkompression, Prozessoptimierung, Aerodynamik: Eine Tour Durch die Skalen

    NASA Astrophysics Data System (ADS)

    Dahmen, Wolfgang; Marquardt, Wolfgang

    Enorm gestiegene Rechnerkapazitäten ermutigen zu einer immer genaueren Erschließung komplexer Prozesse in Natur- und Ingenieurwissenschaften durch numerische Simulation. Die Mathematik als Schnittstelle zwischen realer und digitaler Welt liefert einerseits die Grundlagen zur Formulierung notwendigerweise vereinfachter Modelle der Realität. Andererseits bietet sie aber auch die methodischen Grundlagen für den Entwurf effizienter Algorithmen, die aus solchen Modellen quantitative Information gewinnen können. Eine zentrale Herausforderung liegt dabei in der Tatsache, dass reale Prozesse meist durch relevante Anteile auf einer riesigen Spannweite von Längenskalen getrieben werden. Die Entwicklung mathematischer Methoden zur Behandlung von Mehrskaligkeit ist daher von wesentlicher Bedeutung. In diesem Artikel wird dies anhand jüngster Entwicklungen in ganz unterschiedlichen Anwendungsbereichen erklärt und illustriert, auch um deutlich zu machen, wieviele "Fliegen“ man mit einer "mathematischen Klappe“ schlagen kann. Insbesondere werden grundlegende, auf Waveletzerlegung beruhende Prinzipien zunächst im Rahmen der Bildkompression und -kodierung auf weitgehend elementare Weise erklärt. Es wird dann aufgezeigt, dass diese Konzepte in ganz ähnlicher Weise bei der Datenanalyse im Zusammenhang mit verfahrenstechnischen Anwendungen, bei großskaligen Optimierungsproblemen der Prozessindustrie sowie bei komplexen Strömungsproblemen wie in aerodynamischen Anwendungen zum Tragen kommen. Stabile Zerlegungen in Anteile unterschiedlicher Längenskalen eröffnen dabei einen Zugang zu adaptiven Lösungskonzepten, die in der Lage sind, automatisch Rechnerresourcen dort zu plazieren, wo sie zu einer ökonomischen Realisierung der gewünschten Lösungsqualität, etwa in Form von Genauigkeitstoleranzen, benötigt werden.

  12. Rekonfigurationstechniken und Anwendungsgebiete für ein programmierbares Gm-C Analog-Filter

    NASA Astrophysics Data System (ADS)

    Becker, J.; Henrici, F.; Manoli, Y.

    2006-09-01

    FPAAs (Field Programmable Analog Arrays) erlauben es, analoge Signalübertragungsfunktionen auf Hardware abzubilden, die von veränderbaren digitalen Konfigurationsdaten abhängen. Sowohl für das Design von Filterstrukturen auf Systemebene als auch für die genaue Simulation ihrer analogen Übertragungsfunktion auf Transistorebene ist es dabei notwendig, die entsprechenden Konfigurationsdaten einzugeben bevor die Phasen/Betragsanalyse durchgeführt werden kann. Die vorliegende Arbeit stellt ein graphisches Entwurfsprogramm zur Instantiierung von analogen Filtern für ein FPAA mit 17 gm-C Blöcken vor. Es wird über erste Simulationsergebnisse berichtet, die die Machbarkeit mit Eckfrequenzen bis zu hundert Mhz bestätigen. Simulierte Übertragungsfunktionen von grundlegenden Bausteinen werden mit der Theorie verglichen und zu einer exemplarischen Instantiierung eines Butterworth-Filters der vierten Ordnung weitergeführt.

  13. Eine Beziehung seit 650 Jahren: Universität Wien und Kloster Melk - Katalog zur Sonderausstellung

    NASA Astrophysics Data System (ADS)

    Bruckmüller, Ernst; Niederkorn-Bruck, Meta; Beck, Paul G.; Deibl, Jakob; Deibl, Johannes; Denk, Ulrike; Ellegast, Burkard; Floßmann, Gerhard; Glaßner, Gottfried; Kalteis, Bernadette; Kowarik, Wilfried; Rotheneder, Martin

    2015-04-01

    University of Vienna was founded in 1365 and celebrates its 650 anniversary in 2015. Due to the university's anniversary, the Benedictine abbey of Melk, Austria presents an exhibition, depicting six and half centuries of university history and collaboration between the university as well as the abbey in all disciplines present at medieval universities. The publication describes the historic frame work as well as case-by-case descriptions of displayed manuscripts, prints and artifacts. Die Universität Wien wurde 1365 gegründet und feiert 2015 ihr 650jähriges Bestehen. Aus Anlass dieses Jubiläums präsentiert das Benediktiner Stift Melk eine Ausstellung, in der sechseinhalb Jahrhunderte Universistaetsgeschichte aufgearbeitet werden, sowie die Zusammenarbeit zwischen Universität und Abtei auf allen Themenbereichen, die an mittelalterlichen Universitäten angeboten wurden. Die Publikation bietet eine historische Zusammenfassung sowie eine Detailbeschreibung der ausgestellten Handschriften, Drucke sowie Gegenstände.

  14. Transcriptome Analysis Provides a Preliminary Regulation Route of the Ethylene Signal Transduction Component, SlEIN2, during Tomato Ripening.

    PubMed

    Wang, Rui-Heng; Yuan, Xin-Yu; Meng, Lan-Huan; Zhu, Ben-Zhong; Zhu, Hong-Liang; Luo, Yun-Bo; Fu, Da-Qi

    2016-01-01

    Ethylene is crucial in climacteric fruit ripening. The ethylene signal pathway regulates several physiological alterations such as softening, carotenoid accumulation and sugar level reduction, and production of volatile compounds. All these physiological processes are controlled by numerous genes and their expression simultaneously changes at the onset of ripening. Ethylene insensitive 2 (EIN2) is a key component for ethylene signal transduction, and its mutation causes ethylene insensitivity. In tomato, silencing SlEIN2 resulted in a non-ripening phenotype and low ethylene production. RNA sequencing of SlEIN2-silenced and wild type tomato, and differential gene expression analyses, indicated that silencing SlEIN2 caused changes in more than 4,000 genes, including those related to photosynthesis, defense, and secondary metabolism. The relative expression level of 28 genes covering ripening-associated transcription factors, ethylene biosynthesis, ethylene signal pathway, chlorophyll binding proteins, lycopene and aroma biosynthesis, and defense pathway, showed that SlEIN2 influences ripening inhibitor (RIN) in a feedback loop, thus controlling the expression of several other genes. SlEIN2 regulates many aspects of fruit ripening, and is a key factor in the ethylene signal transduction pathway. Silencing SlEIN2 ultimately results in lycopene biosynthesis inhibition, which is the reason why tomato does not turn red, and this gene also affects the expression of several defense-associated genes. Although SlEIN2-silenced and green wild type fruits are similar in appearance, their metabolism is significantly different at the molecular level.

  15. EIN3 interferes with the sulfur deficiency signaling in Arabidopsis thaliana through direct interaction with the SLIM1 transcription factor.

    PubMed

    Wawrzyńska, Anna; Sirko, Agnieszka

    2016-12-01

    Sulfur deficiency in plants leads to metabolic reprogramming through changes of gene expression. SLIM1 is so far the only characterized transcription factor associated strictly with sulfur deficiency stress in Arabidopsis thaliana. It belongs to the same protein family as EIN3, a major positive switch of ethylene signaling pathway. It binds to the specific cis sequence called UPE-box. Here we show that SLIM1 interacts with UPE-box as a homodimer. Interestingly, the same region of the protein is used for heterodimerization with EIN3; however, the heterodimer is not able to recognize UPE-box. Expression of several SLIM1-dependent genes is enhanced in sulfur deficiency grown Arabidopsis ein3-1 seedlings (with mutated EIN3 protein). This implies a possible regulatory mechanism of ethylene in sulfur metabolism through direct EIN3-SLIM1 interaction.

  16. Effect of ciprofloxacin antibiotic on the partial-nitritation process and bacterial community structure of a submerged biofilter.

    PubMed

    Gonzalez-Martinez, A; Rodriguez-Sanchez, A; Martinez-Toledo, M V; Garcia-Ruiz, M-J; Hontoria, E; Osorio-Robles, F; Gonzalez-Lopez, J

    2014-04-01

    A partial-nitritation bench-scale submerged biofilter was used for the treatment of synthetic wastewater containing a high concentration of ammonium in order to study the influence of the antibiotic ciprofloxacin on the partial-nitritation process and biodiversity of the bacterial community structure. The influence of ciprofloxacin was evaluated in four partial-nitritation bioreactors working in parallel, which received sterile synthetic wastewater amended with 350 ng/L of ciprofloxacin (Experiment 1), synthetic wastewater without ciprofloxacin (Experiment 2), synthetic wastewater amended with 100 ng/L of ciprofloxacin (Experiment 3) and synthetic wastewater amended with 350 ng/L of ciprofloxacin (Experiment 4). The concentration of 100 ng/L of antibiotics demonstrated that the partial-nitritation process, microbial biomass and bacterial structure generated by tag-pyrosequencing adapted progressively to the conditions in the bioreactor. However, high concentrations of ciprofloxacin (350 ng/L) induced a decay of the partial-nitritation process, while the total microbial biomass was increased. Within the same experiment, the bacterial community experienced sequential shifts with a clear reduction of the ammonium oxidation bacteria (AOB) and an evident increase of Commamonas sp., which have been previously reported to be ciprofloxacin-resistant. Our study suggests the need for careful monitoring of the concentration of antibiotics such as ciprofloxacin in partial-nitritation bioreactors, in order to choose and maintain the most appropriate conditions for the proper operation of the system.

  17. Upflow bio-filter circuit (UBFC): biocatalyst microbial fuel cell (MFC) configuration and application to biodiesel wastewater treatment.

    PubMed

    Sukkasem, Chontisa; Laehlah, Sunee; Hniman, Adilan; O'thong, Sompong; Boonsawang, Piyarat; Rarngnarong, Athirat; Nisoa, Mudtorlep; Kirdtongmee, Pansak

    2011-11-01

    A biodiesel wastewater treatment technology was investigated for neutral alkalinity and COD removal by microbial fuel cell. An upflow bio-filter circuit (UBFC), a kind of biocatalyst MFC was renovated and reinvented. The developed system was combined with a pre-fermented (PF) and an influent adjusted (IA) procedure. The optimal conditions were operated with an organic loading rate (OLR) of 30.0 g COD/L-day, hydraulic retention time (HRT) of 1.04 day, maintained at pH level 6.5-7.5 and aerated at 2.0 L/min. An external resistance of circuit was set at 10 kΩ. The purposed process could improve the quality of the raw wastewater and obtained high efficiency of COD removal of 15.0 g COD/L-day. Moreover, the cost of UBFC system was only US$1775.7/m3 and the total power consumption was 0.152 kW/kg treated COD. The overall advantages of this invention are suitable for biodiesel wastewater treatment.

  18. Membrane fouling mitigation in a moving bed membrane bioreactor combined with anoxic biofilter for treatment of saline wastewater from mariculture.

    PubMed

    Song, Weilong; You, Hong; Li, Zhipeng; Liu, Feng; Qi, Peishi; Wang, Fang; Li, Yizhu

    2017-11-01

    Membrane fouling mitigation in a novel AF-MBMBR system (moving bed membrane bioreactor (10L) coupled with anoxic biofilter (4L)) under high salinity condition (35‰) was systematically investigated. Pre-positioned AF served as a pretreatment induced significant decrease of suspended biomass by 85% and dissolved organic matters by 51.7% in subsequent MBR, which resulted in a reduction of cake layer formation. Based on this, sponge bio-carriers in MBMBR further alleviated the fouling propensity by modifying extracellular polymeric substances (EPS) properties. The protein component in EPS decreased from 181.4 to 116.5mg/g MLSS, with a decline of protein/carbohydrate ratio from 4.6 to 3.4. In particular, elimination of hydrophobic groups like aromatic protein-like substance in EPS was detected. These caused the less biomass deposition on membrane surface, thereby alleviating membrane fouling. In summary, mitigation of membrane fouling in AF-MBMBR should be attributed to contributions from both pre-positioned AF and sponge bio-carriers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Phenol Biodegradation by Free and Immobilized Candida tropicalis RETL-Crl on Coconut Husk and Loofah Packed in Biofilter Column

    NASA Astrophysics Data System (ADS)

    Shazryenna, D.; Ruzanna, R.; Jessica, M. S.; Piakong, M. T.

    2015-04-01

    Phenols and its derivatives are environmental pollutant commonly found in many industrial effluents. It is toxic in nature and causes various health hazards. However, they are poorly removed in conventional biological processes due to their toxicity. Immobilization of microbial cells has received increasing interest in the field of waste treatment and creates opportunities in a wide range of sectors including environmental pollution control. Live cells of phenol-degrading yeast, Candida tropicalis RETL-Crl, were immobilized on coconut husk and loofah by adsorption. The immobolized particle was packed into biofilter column which used for continuous treatment of a phenol with initial phenol concentration of 3mM. Both loofah and coconut husk have similar phenol biodegradation rate of 0.0188 gL-1h-1 within 15 hours to achieve a phenol removal efficiency of 100%. However loofah have lower biomass concentration of 4.22 gL-1 compared to biomass concentration on coconut husk, 4.39 gL-1. Coconut husk contain higher biomass concentration which makes it better support material than loofah. Fibrous matrices such as loofah and coconut husk provide adequate supporting surfaces for cell adsorption, due to their high specific surface area. Therefore, coconut husk and loofah being an agricultural waste product have the potential to be used as low-cost adsorbent and support matrix for microbial culture immobilization for the removal of organic pollutant from wastewater.

  20. Kinetics of microbial growth and biodegradation of methanol and toluene in biofilters and an analysis of the energetic indicators.

    PubMed

    Avalos Ramirez, Antonio; Bénard, Sandrine; Giroir-Fendler, Anne; Jones, J Peter; Heitz, Michèle

    2008-11-25

    The kinetics of microbial growth and the biodegradation of methanol and toluene in (a) biofilters (BFs), and (b) biotrickling filters (BTFs), packed with inert materials, has been studied and analyzed. The specific growth rate, mu, for the treatment of methanol was 0.037h(-1) for a wide range of operating conditions. In the BF, mu was found to be a function of the methanol and toluene concentrations in the biofilm. In the BF used for treating methanol, mu was found to be affected by (1) the nitrogen concentration present in the nutrient solution, and (2) the kind of packing material employed. The kinetics of the methanol and toluene biodegradations were also analyzed using "mixed order" models. A Michaelis-Menten model type provided a good fit for the elimination capacity (EC) of the BTF treating methanol, while a Haldane model type provided a good fit to the EC of the BF treating methanol and toluene. The carbon dioxide production rate was related to the packed bed temperature and the content of the volatile solids within the biofilm. For the BF, the ratio of temperature/carbon dioxide production rate (PCO(2)) was 0.024 degrees C per unit of PCO(2), and for the BTF it was 0.15 degrees C per unit of PCO(2).

  1. Realization of microbial community stratification for single-stage nitrogen removal in a sequencing batch biofilter granular reactor.

    PubMed

    Sun, Na; Ge, Chenghao; Ahmad, Hafiz Adeel; Gao, Baoyu; Ni, Shou-Qing

    2017-10-01

    A permanent microbial stratified nitrogen removal system coupling anammox with partial nitrification (SNAP) in a sequencing batch biofilter granular reactor (SBBGR) was successfully constructed for the treatment of ammonia-rich wastewater. With a nitrogen loading rate of 0.1kgNm(-3)·d(-1), the maximal ammonia and total nitrogen removal efficiencies could reach up to 96.08% and 84.86% on day 108, respectively. The pH, DO profiles revealed a switch of functional species (AOB and anammox) at a typical intermittent aeration cycle. qPCR and high throughput analyses certified a stable spatial microbial stratified community structure. Although, anammox preferred strict anaerobic environment while AOB needed oxygen, a special stratified community structure contributed to conquer this obstacle. Moreover, Bacteroidet, Chlorobi, OD1, Planctomycetes, and Proteobacteria were the dominant species in the SBBGR. Although we have predicted the possible pathways of nitrogen transformation, further studies are needed to validate the pathways in enzymology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Genetic associations as indices of nitrogen cycling rates in an aerobic denitrification biofilter used for groundwater remediation.

    PubMed

    Zhang, Yan; Ji, Guodong; Wang, Rongjing

    2015-10-01

    An aerobic denitrification biofilter (ADB) for groundwater remediation was developed with high removal efficiencies (total nitrogen (TN): 82.3-95.8%; NO3(-)-N: 93.2-98.2%). Nitrate (NO3(-)-N) transformation rates stabilized between 21.0 and 23.4 g/(m(3) h), whereas nitrite (NO2(-)-N) and ammonium (NH4(+)-N) transformation rates remained less than 6.0 g/(m(3) h) as the dissolved oxygen (DO) level increased from 1.0 mg/L to 6.0 mg/L. Nitric oxide (NO) and nitrous oxide (N2O) accumulated with great fluctuations (NO: 0-1.6×10(-3) g/(m(3) h); N2O: 0.1-1.1g/(m(3)h)) throughout the experiment. This study suggested that gene associations reflect quantitative relationships with aerobic denitrification rates and can provide useful information regarding aerobic denitrification processes in groundwater. Especially, the qnorB/nosZ ratio acts as the main driver for NO3(-)-N and NH4(+)-N transformation, while the qnorB/nosZ ratio followed by the (nirS+nirK)/nosZ ratio serve a dominant role in the accumulation of N2O and NO. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. The effects of different seeding ratios on nitrification performance and biofilm formation in marine recirculating aquaculture system biofilter.

    PubMed

    Zhu, Songming; Shen, Jiazheng; Ruan, Yunjie; Guo, Xishan; Ye, Zhangying; Deng, Yale; Shi, Mingming

    2016-07-01

    Rapid start-up of biofilter is essential for intensive marine recirculating aquaculture system (RAS) production. This study evaluated the nitrifying biofilm formation using mature biofilm as an inoculum to accelerate the process in RAS practice. The effects of inoculation ratios (0-15 %) on the reactor performance and biofilm structure were investigated. Complete nitrification was achieved rapidly in reactors with inoculated mature biofilm (even in 32 days when 15 % seeding ratio was applied). However, the growth of target biofilm on blank carrier was affected by the mature biofilm inoculated through substrate competition. The analysis of extracellular polymeric substance (EPS) and nitrification rates confirmed the divergence of biofilm cultivation among reactors. Besides, three N-acyl-homoserine lactones (AHLs) were found in the process, which might regulate the activities of biofilm. Multivariate analysis based on non-metric multidimensional scaling (nMDS) also indicated the great roles of AHLs and substrate supply which might fundamentally determine varied cultivation performance on target biofilm.

  4. Use of plant genotoxicity bioassay for the evaluation of efficiency of algal biofilters in bioremediation of toxic industrial effluent.

    PubMed

    Abdel Migid, Hala M; Azab, Yehia A; Ibrahim, Waeel M

    2007-01-01

    The toxicity and efficacy of an algal-based bioremediation technology were assessed through bioassays for ecological risk of contaminated industrial effluents. The algal bioremoval of heavy metals was evaluated using an in vitro approach. Phytogenotoxicity tests were conducted with Allium cepa and Vicia faba plants to evaluate the genotoxicity of the industrial effluents before and after treatment with different kinds of algal biofilters (BF). Root cells were exposed for 24 h to different dilutions of both raw and treated effluent of a chemical fertilizer factory. Three cytogenetic endpoints were used to assess the mutagenic potencies of the industrial effluent: mitotic inhibition, mitotic chromosome aberrations, and nuclear irregularities in interphase cells. Before algal treatment, the industrial effluent caused strong genotoxic effects represented by severe inhibition in mitotic activity of meristematic cells and high frequency of both chromosome and nucleus abnormalities. After algal treatment, the cytotoxic effects of 30% and 60% concentrations of the treated effluent were comparable to those of 5% and 10% concentrations before treatment, respectively, and the frequency of both chromosome and nuclear abnormalities declined by approximately 50%. Statistical analysis of the data indicates a significant reduction in genotoxicity associated with a remarkable reduction in heavy metal concentrations after bioremediation by algal BF. The Allium and Vicia genotoxicity approach was effective in monitoring bioremediated effluent for toxicity.

  5. An advanced anaerobic biofilter with effluent recirculation for phenol removal and methane production in treatment of coal gasification wastewater.

    PubMed

    Li, Yajie; Tabassum, Salma; Zhang, Zhenjia

    2016-09-01

    An advanced anaerobic biofilter (AF) was introduced for the treatment of coal gasification wastewater (CGW), and effluent recirculation was adopted to enhance phenol removal and methane production. The results indicated that AF was reliable in treating diluted CGW, while its efficiency and stability were seriously reduced when directly treating raw CGW. However, its performance could be greatly enhanced by effluent recirculation. Under optimal effluent recirculation of 0.5 to the influent, concentrations of chemical oxygen demand (COD) and total phenol in the effluent could reach as low as 234.0 and 14.2mg/L, respectively. Also, the rate of methane production reached 169.0mLCH4/L/day. Though CGW seemed to restrain the growth of anaerobic microorganisms, especially methanogens, the inhibition was temporary and reversible, and anaerobic bacteria presented strong tolerance. The activities of methanogens cultivated in CGW could quickly recover on feeding with glucose wastewater (GW). However, the adaptability of anaerobic bacteria to the CGW was very poor and the activity of methanogens could not be improved by long-term domestication. By analysis using the Haldane model, it was further confirmed that high effluent recirculation could result in high activity for hydrolytic bacteria and substrate affinity for toxic matters, but only suitable effluent recirculation could result in high methanogenic activity. Copyright © 2016. Published by Elsevier B.V.

  6. Inhibition of boric acid and sodium borate on the biological activity of microorganisms in an aerobic biofilter.

    PubMed

    Güneş, Y

    2013-01-01

    The aim of this work was to study the inhibition effect of boric acid and sodium borate on the treatment of boron containing synthetic wastewater by a down flow aerobic fixed bed biofilm reactor at various chemical oxygen demand (COD)/boron ratios (0.47-20.54). The inhibitory effect of boron on activated sludge was evaluated on the basis of COD removal during the experimental period. The biofilter (effective volume = 2.5 L) was filled with a ring of plastic material inoculated with acclimated activated sludge. The synthetic wastewater composed of glucose, urea, KH2PO4, MgSO4, Fe2 SO4, ZnSO4 x 7H20, KCl, CaCl2, and di-sodium tetraborate decahydrate or boric acid (B = 100-2000 mg L(-1)). The biological treatment of boron containing wastewater resulted in a low treatment removal rate due to the reduced microbial activity as a result of toxic effects of high boron concentrations. The decrease in the COD removal rate by the presence of either boric acid or sodium borate was practically indistinguishable. It was observed from the experiments that about 90-95% of COD removal was possible at high COD/boron ratios.

  7. Separation anxiety: An analysis of ethylene-induced cleavage of EIN2

    USDA-ARS?s Scientific Manuscript database

    Since the discovery of the CTR1 protein kinase and the endoplasmic reticulum (ER)-localized EIN2 protein nearly 20 y ago, plant biologists have wondered how these proteins respectively serve as negative and positive regulators of ethylene-mediated signal transduction in plants. Now with the publicat...

  8. New paradigm in ethylene signaling: EIN2, the central regulator of the signaling pathway, interacts directly with the upstream receptors.

    PubMed

    Bisson, Melanie M A; Groth, Georg

    2011-01-01

    The membrane protein ETHYLENE INSENSITIVE2 (EIN2), which is supposed to act between the soluble serine/threonine kinase CTR1 and the EIN3/EIL family of transcription factors, is a central and most critical element of the ethylene signaling pathway in Arabidopsis. In a recent study, we have identified that EIN2 interacts tightly with all members of the Arabidopsis ethylene receptor family - proteins that mark the starting point of the signaling pathway. Our studies show consistently that the kinase domain of the receptors is essential for the formation of the EIN2-receptor complex. Furthermore, mutational analysis demonstrates that phosphorylation is a key mechanism in controlling the interaction of EIN2 and the ethylene receptors. Interaction studies in the presence of the ethylene agonist cyanide revealed a causal link between hormone binding and complex formation. In the presence of the plant hormone agonist the auto-kinase activity of the receptors is inhibited and the non-phosphorylated kinase domain of the receptors binds tightly to the carboxyl-terminal domain of EIN2. In the absence of cyanide inhibition of the auto-kinase activity is relieved and complex formation with the phosphorylated kinase domain of the receptors is reduced. Our data suggest a novel model on the integration of EIN2 in the ethylene signaling pathway.

  9. ORA59 and EIN3 interaction couples jasmonate-ethylene synergistic action to antagonistic salicylic acid regulation of PDF expression.

    PubMed

    He, Xiang; Jiang, Jishan; Wang, Changquan; Dehesh, Katayoon

    2017-02-07

    Hormonal crosstalk is central for tailoring plant responses to the nature of challenges encountered. The role of antagonism between the two major defense hormones, salicylic acid (SA) and jasmonic acid (JA), and modulation of this interplay by ethylene (ET) in favor of JA signaling pathway in plant stress responses is well recognized, but the underlying mechanism is not fully understood. Here, we show the opposing function of two transcription factors, ethylene insensitive3 (EIN3) and EIN3-Like1 (EIL1), in SA-mediated suppression and JA-mediated activation of PLANT DEFENSIN1.2 (PDF1.2). This functional duality is mediated via their effect on protein, not transcript levels of the PDF1.2 transcriptional activator octadecanoid-responsive arabidopsis59 (ORA59). Specifically, JA induces ORA59 protein levels independently of EIN3/EIL1, whereas SA reduces the protein levels dependently of EIN3/EIL1. Co-infiltration assays revealed nuclear co-localization of ORA59 and EIN3, and split-luciferase together with yeast-two-hybrid assays established their physical interaction. The functional ramification of the physical interaction is EIN3-dependent degradation of ORA59 by the 26S proteasome. These findings allude to SA-responsive reduction of ORA59 levels mediated by EIN3 binding to and targeting of ORA59 for degradation, thus nominating ORA59 pool as a coordination node for the antagonistic function of ET/JA and SA.

  10. Effect of loading types on performance characteristics of a trickle-bed bioreactor and biofilter during styrene/acetone vapor biofiltration.

    PubMed

    Halecky, Martin; Paca, Jan; Kozliak, Evguenii; Jones, Kim

    2016-07-02

    A 2:1 (w/w) mixture of styrene (STY) and acetone (AC) was subjected to lab-scale biofiltration under varied loading in both a trickle bed reactor (TBR) and biofilter (BF) to investigate substrate interactions and determine the limits of biofiltration efficiency of typical binary air pollutant mixtures containing both hydrophobic and polar components. A comparison of the STY/AC mixture degradation in the TBR and BF revealed higher pollutant removal efficiencies and degradation rates in the TBR, with the pollutant concentrations increasing up to the overloading limit. The maximum styrene degradation rates were 12 and 8 gc m(-3) h(-1) for the TBR and BF, respectively. However, the order of performance switched in favor of the BF when the loading was conducted by increasing air flow rate while keeping the inlet styrene concentration (Cin) constant in contrast to loading by increasing Cin. This switch may be due to a drastic difference in the effective surface area between these two reactors, so the biofilter becomes the reactor of choice when the rate-limiting step switches from biochemical processes to mass transfer by changing the loading mode. The presence of acetone in the mixture decreased the efficiency of styrene degradation and its degradation rate at high loadings. When the overloading was lifted by lowering the pollutant inlet concentrations, short-term back-stripping of both substrates in both reactors into the outlet air was observed, with a subsequent gradual recovery taking several hours and days in the BF and TBR, respectively. Removal of excess biomass from the TBR significantly improved the reactor performance. Identification of the cultivable strains, which was performed on Day 763 of continuous operation, showed the presence of 7 G(-) bacteria, 2 G(+) bacteria and 4 fungi. Flies and larvae of Lycoriella nigripes survived half a year of the biofilter operation by feeding on the biofilm resulting in the maintenance of a nearly constant pressure drop.

  11. Community Analysis of Biofilters Using Fluorescence In Situ Hybridization Including a New Probe for the Xanthomonas Branch of the Class Proteobacteria

    PubMed Central

    Friedrich, Udo; Naismith, Michèle M.; Altendorf, Karlheinz; Lipski, André

    1999-01-01

    Domain-, class-, and subclass-specific rRNA-targeted probes were applied to investigate the microbial communities of three industrial and three laboratory-scale biofilters. The set of probes also included a new probe (named XAN818) specific for the Xanthomonas branch of the class Proteobacteria; this probe is described in this study. The members of the Xanthomonas branch do not hybridize with previously developed rRNA-targeted oligonucleotide probes for the α-, β-, and γ-Proteobacteria. Bacteria of the Xanthomonas branch accounted for up to 4.5% of total direct counts obtained with 4′,6-diamidino-2-phenylindole. In biofilter samples, the relative abundance of these bacteria was similar to that of the γ-Proteobacteria. Actinobacteria (gram-positive bacteria with a high G+C DNA content) and α-Proteobacteria were the most dominant groups. Detection rates obtained with probe EUB338 varied between about 40 and 70%. For samples with high contents of gram-positive bacteria, these percentages were substantially improved when the calculations were corrected for the reduced permeability of gram-positive bacteria when formaldehyde was used as a fixative. The set of applied bacterial class- and subclass-specific probes yielded, on average, 58.5% (± a standard deviation of 23.0%) of the corrected eubacterial detection rates, thus indicating the necessity of additional probes for studies of biofilter communities. The Xanthomonas-specific probe presented here may serve as an efficient tool for identifying potential phytopathogens. In situ hybridization proved to be a practical tool for microbiological studies of biofiltration systems. PMID:10427047

  12. Quantification of uncertainty in modelled partitioning and removal of heavy metals (Cu, Zn) in a stormwater retention pond and a biofilter.

    PubMed

    Vezzaro, L; Eriksson, E; Ledin, A; Mikkelsen, P S

    2012-12-15

    Strategies for reduction of micropollutant (MP) discharges from stormwater drainage systems require accurate estimation of the potential MP removal in stormwater treatment systems. However, the high uncertainty commonly affecting stormwater runoff quality modelling also influences stormwater treatment models. This study identified the major sources of uncertainty when estimating the removal of copper and zinc in a retention pond and a biofilter by using a conceptual dynamic model which estimates MP partitioning between the dissolved and particulate phases as well as environmental fate based on substance-inherent properties. The two systems differ in their main removal processes (settling and filtration/sorption, respectively) and in the time resolution of the available measurements (composite samples and pollutographs). The most sensitive model factors, identified by using Global Sensitivity Analysis (GSA), were related to the physical characteristics of the simulated systems (flow and water losses) and to the fate processes related to Total Suspended Solids (TSS). The model prediction bounds were estimated by using the Generalized Likelihood Uncertainty Estimation (GLUE) technique. Composite samples and pollutographs produced similar prediction bounds for the pond and the biofilter, suggesting a limited influence of the temporal resolution of samples on the model prediction bounds. GLUE highlighted model structural uncertainty when modelling the biofilter, due to disregard of plant-driven evapotranspiration, underestimation of sorption and neglect of oversaturation with respect to minerals/salts. The results of this study however illustrate the potential for the application of conceptual dynamic fate models base on substance-inherent properties, in combination with available datasets and statistical methods, to estimate the MP removal in different stormwater treatment systems and compare with environmental quality standards targeting the dissolved MP fraction

  13. Long-term ammonia removal in a coconut fiber-packed biofilter: analysis of N fractionation and reactor performance under steady-state and transient conditions.

    PubMed

    Baquerizo, Guillermo; Maestre, Juan P; Machado, Vinicius C; Gamisans, Xavier; Gabriel, David

    2009-05-01

    A comprehensive study of long-term ammonia removal in a biofilter packed with coconut fiber is presented under both steady-state and transient conditions. Low and high ammonia loads were applied to the reactor by varying the inlet ammonia concentration from 90 to 260 ppm(v) and gas contact times ranging from 20 to 36 s. Gas samples and leachate measurements were periodically analyzed and used for characterizing biofilter performance in terms of removal efficiency (RE) and elimination capacity (EC). Also, N fractions in the leachate were quantified to both identify the experimental rates of nitritation and nitratation and to determine the N leachate distribution. Results showed stratification in the biofilter activity and, thus, most of the NH(3) removal was performed in the lower part of the reactor. An average EC of 0.5 kg N-NH(3)m(-3)d(-1) was obtained for the whole reactor with a maximum local average EC of 1.7 kg N-NH(3)m(-3)d(-1). Leachate analyses showed that a ratio of 1:1 of ammonium and nitrate ions in the leachate was obtained throughout steady-state operation at low ammonia loads with similar values for nitritation and nitratation rates. Low nitratation rates during high ammonia load periods occurred because large amounts of ammonium and nitrite accumulated in the packed bed, thus causing inhibition episodes on nitrite-oxidizing bacteria due to free ammonia accumulation. Mass balances showed that 50% of the ammonia fed to the reactor was oxidized to either nitrite or nitrate and the rest was recovered as ammonium indicating that sorption processes play a fundamental role in the treatment of ammonia by biofiltration.

  14. Chemo-mechanical modification of cottonwood for Pb(2+) removal from aqueous solutions: Sorption mechanisms and potential application as biofilter in drip-irrigation.

    PubMed

    Mosa, Ahmed; El-Ghamry, Ayman; Trüby, Peter; Omar, Mahmoud; Gao, Bin; Elnaggar, Abdelhamid; Li, Yuncong

    2016-10-01

    Using biomass (e.g. crop residues) and its derivatives as biosorbents have been recognized as an eco-friendly technique for wastewater decontamination. In this study, mechanically modified cottonwood was further activated with KOH to improve its sorption of Pb(2+). In addition, its potential as a biofilter to safeguard radish (Raphanus sativus, L.) against Pb-stress was evaluated in a gravity-fed drip irrigation system. Physiochemical properties of the chemo-mechanically activated cottonwood (CMACW) and the mechanically activated cottonwood (MACW) before and after sorption process were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), digital selected-area electron diffraction (SAED) and Fourier transform infrared spectroscopy (FTIR). After activation, several sorption mechanisms (i.e. precipitation, electrostatic outer- and inner-sphere complexation) were responsible for the higher sorption capacity of CMACW as compared with MACW (8.55 vs. 7.28 mg g(-1)). Sorption kinetics and isotherms fitted better with the pseudo-second-order and Langmuir models as compared with the pseudo-first-order and Freundlich models, respectively. In the gravity-fed drip irrigation system, the CMACW biofilter reduced the accumulation of Pb in radish roots and shoots and avoided reaching the toxic limits in some cases. Soil types had a significant effect on Pb(2+) bioavailability because of the difference in sorption ability. Findings from this study showed that CMACW biofilter can be used as a safeguard for wastewater irrigation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Coal-Packed Methane Biofilter for Mitigation of Green House Gas Emissions from Coal Mine Ventilation Air

    PubMed Central

    Limbri, Hendy; Gunawan, Cindy; Thomas, Torsten; Smith, Andrew; Scott, Jason; Rosche, Bettina

    2014-01-01

    Methane emitted by coal mine ventilation air (MVA) is a significant greenhouse gas. A mitigation strategy is the oxidation of methane to carbon dioxide, which is approximately twenty-one times less effective at global warming than methane on a mass-basis. The low non-combustible methane concentrations at high MVA flow rates call for a catalytic strategy of oxidation. A laboratory-scale coal-packed biofilter was designed and partially removed methane from humidified air at flow rates between 0.2 and 2.4 L min−1 at 30°C with nutrient solution added every three days. Methane oxidation was catalysed by a complex community of naturally-occurring microorganisms, with the most abundant member being identified by 16S rRNA gene sequence as belonging to the methanotrophic genus Methylocystis. Additional inoculation with a laboratory-grown culture of Methylosinus sporium, as investigated in a parallel run, only enhanced methane consumption during the initial 12 weeks. The greatest level of methane removal of 27.2±0.66 g methane m−3 empty bed h−1 was attained for the non-inoculated system, which was equivalent to removing 19.7±2.9% methane from an inlet concentration of 1% v/v at an inlet gas flow rate of 1.6 L min−1 (2.4 min empty bed residence time). These results show that low-cost coal packing holds promising potential as a suitable growth surface and contains methanotrophic microorganisms for the catalytic oxidative removal of methane. PMID:24743729

  16. Abatement of styrene waste gas emission by biofilter and biotrickling filter: comparison of packing materials and inoculation procedures.

    PubMed

    Pérez, M C; Álvarez-Hornos, F J; Portune, K; Gabaldón, C

    2015-01-01

    The removal of styrene was studied using two biofilters packed with peat and coconut fibre (BF1-P and BF2-C, respectively) and one biotrickling filter (BTF) packed with plastic rings. Two inoculation procedures were applied: an enriched culture with strain Pseudomonas putida CECT 324 for BFs and activated sludge from a municipal wastewater treatment plant for the BTF. Inlet loads (ILs) between 10 and 45 g m(-3) h(-1) and empty bed residence times (EBRTs) from 30 to 120 s were applied. At inlet concentrations ranging between 200 and 400 mg Nm(-3), removal efficiencies between 70 % and 95 % were obtained in the three bioreactors. Maximum elimination capacities (ECs) of 81 and 39 g m(-3) h(-1) were obtained for the BF1-P and BF2-C, respectively (IL of 173 g m(-3) h(-1) and EBRT of 60 s in BF1-P; IL of 89 g m(-3) h(-1) and EBRT of 90 s in BF2-C). A maximum EC of 52 g m(-3) h(-1) was obtained for the BTF (IL of 116 g m(-3) h(-1), EBRT of 45 s). Problems regarding high pressure drop appeared in the peat BF, whereas drying episodes occurred in the coconut fibre BF. DGGE revealed that the pure culture used for BF inoculation was not detected by day 105. Although two different inoculation procedures were applied, similar styrene removal at the end of the experiments was observed. The use as inoculum of activated sludge from municipal wastewater treatment plant appears a more feasible option.

  17. Evaluation of a cost effective technique for treating aquaculture water discharge using Lolium perenne Lam as a biofilter.

    PubMed

    Nduwimana, André; Yang, Xiang-Long; Wang, Li-Ren

    2007-01-01

    Wastewater stabilization ponds generate low cost by-products that are useful for agriculture. The utilization of these by-products for soil amendment and as a source of nutrients for plants requires a high level of sanitation and stabilization of the organic matter, to maintain acceptable levels of soil, water and air quality. In this study, two aquaculture wastewater treatment systems; recirculating system and a floating plant bed system were designed to improve the quality of irrigation water in local communities with low income. In both systems the grass species Lolium perenne Lam was used as a plant biofilter while vegetable specie Amaranthus viridis was used to evaluate the performance of the system and the suitability of the phyto-treated water for irrigation. It was found that the harmful material removal rate for recirculating system was 88.9% for TAN (total ammonia nitrogen), 90% for NO2(-)-N, 64.8% for NO3(-)-N while for floating plant bed system 82.7% for TAN, 82% for NO2(-)-N and 60.5% for NO3(-)-N. Comparative analysis of the efficiency of waste element removal between the two systems revealed that both systems performed well, however, plant growth was not robust for floating plant bed system while recirculating system is energy consuming. Although both systems did not attain sufficient levels of TN (total nitrogen) and TP (total phosphorus) load reduction, the treatment with L. perenne remarkably improved the irrigation water quality. A. viridis plants irrigated with the phyto-treated discharge water had lesser concentrations of heavy metals in their tissues compared to those irrigated with untreated discharge. The control plants irrigated with untreated discharge were also found to be highly lignified with few stems and small leaves.

  18. Coal-packed methane biofilter for mitigation of green house gas emissions from coal mine ventilation air.

    PubMed

    Limbri, Hendy; Gunawan, Cindy; Thomas, Torsten; Smith, Andrew; Scott, Jason; Rosche, Bettina

    2014-01-01

    Methane emitted by coal mine ventilation air (MVA) is a significant greenhouse gas. A mitigation strategy is the oxidation of methane to carbon dioxide, which is approximately twenty-one times less effective at global warming than methane on a mass-basis. The low non-combustible methane concentrations at high MVA flow rates call for a catalytic strategy of oxidation. A laboratory-scale coal-packed biofilter was designed and partially removed methane from humidified air at flow rates between 0.2 and 2.4 L min-1 at 30°C with nutrient solution added every three days. Methane oxidation was catalysed by a complex community of naturally-occurring microorganisms, with the most abundant member being identified by 16S rRNA gene sequence as belonging to the methanotrophic genus Methylocystis. Additional inoculation with a laboratory-grown culture of Methylosinus sporium, as investigated in a parallel run, only enhanced methane consumption during the initial 12 weeks. The greatest level of methane removal of 27.2±0.66 g methane m-3 empty bed h-1 was attained for the non-inoculated system, which was equivalent to removing 19.7±2.9% methane from an inlet concentration of 1% v/v at an inlet gas flow rate of 1.6 L min-1 (2.4 min empty bed residence time). These results show that low-cost coal packing holds promising potential as a suitable growth surface and contains methanotrophic microorganisms for the catalytic oxidative removal of methane.

  19. A comprehensive evaluation of re-circulated bio-filter as a pretreatment process for petroleum refinery wastewater.

    PubMed

    Dai, Xiaoli; Chen, Chunmao; Yan, Guangxu; Chen, Yu; Guo, Shaohui

    2016-12-01

    Conventional biological treatment process is not very efficient for the treatment of petroleum refinery wastewater (PRW) that contains high-concentration of organic contaminants. Prior to biological treatment, an additional pretreatment process for PRW is required for the effluent to meet the discharge standards. While re-circulated bio-filter (RBF) has been applied as a pretreatment process in several PRW treatment plants, its effects have not been comprehensively evaluated. In this study, the parameters of operation, the changes in pollution indexes and contaminant composition in an engineered RBF have been investigated. We found that mainly highly active de-carbonization bacteria were present in the RBF, while no nitrification bacteria were found in the RBF. This indicated the absence of nitrification in this process. The biodegradable organic contaminants were susceptible to degradation by RBF, which decreased the Biological Oxygen Demand (BOD5) by 83.64% and the Chemical Oxygen Demand (CODCr) by 54.63%. Consequently, the alkalinity and pH value of RBF effluent significantly increased, which was unfavorable for the control of operating parameters in subsequent biological treatment. Along with the decrease of CODCr, the RBF effluent exhibited a reduction in biodegradability. 834 kinds of recalcitrant polar organic contaminants remained in the effluent; most of the contaminant molecules having complex structures of aromatic, polycyclic and heterocyclic rings. The results of this study showed that RBF could efficiently treat PRW for biodegradable organic contaminants removal; however, it is difficult to treat bio-refractory organic contaminants, which was unfavorable for the subsequent biological treatment process operation. An improved process might provide overall guarantees for the PRW treatment.

  20. "Hochleistern über die Schulter geschaut" - Konzeption eines Lehrvideos zur Vermittlung von Problemlösekompetenz

    NASA Astrophysics Data System (ADS)

    Kujath, Bertold; Schwill, Andreas

    Leistungsstarke Problemlöser zeigen ein deutlich anderes Vorgehen beim Bearbeiten von typischen Informatikproblemen als schwächere Problemlöser, das hat eine Vergleichsstudie mit Hoch- und Niedrigleistern ergeben. Auffällig war das Fehlen informatikspezifischer Herangehensweisen bei der Problembearbeitung durch Niedrigleister, obwohl die dazu notwendigen Werkzeuge wie etwa Baumstrukturen oder Rekursion durchaus bekannt waren. Aber auch viele allgemeine Empfehlungen der Problemlöseforschung, wie etwa das Zerlegen eines Problems in Teilprobleme oder das Durchführen einer Problemanalyse vor der eigentlichen Bearbeitung, bleiben bei schwachen Problemlösern unbeachtet. Die Frage, wie nun die deutlich effizienteren Strategien der Hochleister didaktisch aufgearbeitet werden können, um sie an Niedrigleister zu vermitteln, soll im vorliegen Beitrag anhand der Konzeption eines Lehrvideos beantwortet werden.

  1. Transcriptome Analysis Provides a Preliminary Regulation Route of the Ethylene Signal Transduction Component, SlEIN2, during Tomato Ripening

    PubMed Central

    Wang, Rui-Heng; Yuan, Xin-Yu; Meng, Lan-Huan; Zhu, Ben-Zhong; Zhu, Hong-liang; Luo, Yun-Bo; Fu, Da-Qi

    2016-01-01

    Ethylene is crucial in climacteric fruit ripening. The ethylene signal pathway regulates several physiological alterations such as softening, carotenoid accumulation and sugar level reduction, and production of volatile compounds. All these physiological processes are controlled by numerous genes and their expression simultaneously changes at the onset of ripening. Ethylene insensitive 2 (EIN2) is a key component for ethylene signal transduction, and its mutation causes ethylene insensitivity. In tomato, silencing SlEIN2 resulted in a non-ripening phenotype and low ethylene production. RNA sequencing of SlEIN2-silenced and wild type tomato, and differential gene expression analyses, indicated that silencing SlEIN2 caused changes in more than 4,000 genes, including those related to photosynthesis, defense, and secondary metabolism. The relative expression level of 28 genes covering ripening-associated transcription factors, ethylene biosynthesis, ethylene signal pathway, chlorophyll binding proteins, lycopene and aroma biosynthesis, and defense pathway, showed that SlEIN2 influences ripening inhibitor (RIN) in a feedback loop, thus controlling the expression of several other genes. SlEIN2 regulates many aspects of fruit ripening, and is a key factor in the ethylene signal transduction pathway. Silencing SlEIN2 ultimately results in lycopene biosynthesis inhibition, which is the reason why tomato does not turn red, and this gene also affects the expression of several defense-associated genes. Although SlEIN2-silenced and green wild type fruits are similar in appearance, their metabolism is significantly different at the molecular level. PMID:27973616

  2. Culture scale-up and immobilisation of a mixed methanotrophic consortium for methane remediation in pilot-scale bio-filters.

    PubMed

    Karthikeyan, Obulisamy Parthiba; Saravanan, Nadarajan; Cirés, Samuel; Alvarez-Roa, Carlos; Razaghi, Ali; Chidambarampadmavathy, Karthigeyan; Velu, Chinnathambi; Subashchandrabose, Gobalakrishnan; Heimann, Kirsten

    2017-02-01

    Robust methanotrophic consortia for methane (CH4) remediation and by-product development are presently not readily available for industrial use. In this study, a mixed methanotrophic consortium (MMC), sequentially enriched from a marine sediment, was assessed for CH4 removal efficiency and potential biomass-generated by-product development. Suitable packing material for bio-filters to support MMC biofilm establishment and growth was also evaluated. The enriched MMC removed ∼7-13% CH4 under a very high gas flow rate (2.5 L min(-1); 20-25% CH4) in continuous-stirred tank reactors (∼10 L working volume) and the biomass contained long-chain fatty acids (i.e. C16 and C18). Cultivation of the MMC on plastic bio-balls abated ∼95-97% CH4 in pilot-scale non-sterile outdoor-operated bio-filters (0.1 L min(-1); 1% CH4). Contamination by cyanobacteria had beneficial effects on treating low-level CH4, by providing additional oxygen for methane oxidation by MMC, suggesting that the co-cultivation of MMC with cyanobacterial mats does not interfere with and may actually be beneficial for remediation of CH4 and CO2 at industrial scale.

  3. Distribution and genetic diversity of microbial populations in the pilot-scale biofilter for simultaneous removal of ammonia, iron and manganese from real groundwater.

    PubMed

    Cheng, Qingfeng; Nengzi, Lichao; Bao, Linlin; Huang, Yang; Liu, Shengyu; Cheng, Xiuwen; Li, Bo; Zhang, Jie

    2017-09-01

    A pilot-scale biofilter treating real groundwater was developed in this study, which showed that ammonia, iron and manganese were mainly removed at 0.4, 0.4 and 0.8 m of the filter bed, respectively, and the corresponding removal efficiencies were 90.82%, 95.48% and 95.90% in steady phase, respectively. The variation of microbial populations in the biofilter during start-up process was also investigated using high-throughput pyrosequencing (HTP). Results indicated that the main functional microbes for ammonia, iron and manganese removal were Nitrosomonas, Crenothrix and Crenothrix, respectively, which was mainly distributed at 0.8, 0, and 0.8 m of the filter bed with a corresponding abundance of 8.7%, 28.12% and 11.33% in steady phase, respectively. Kinds of other bacteria which may be related to methane, hydrogen sulfide and organic matter removal, were also found. In addition, small part of archaea was also detected, such as Candidatus Nitrososphaera, which plays a role in nitritation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Ein mobiler und offener Kernspintomograph: Kernspintomographie für Medizin und Materialforschung

    NASA Astrophysics Data System (ADS)

    Blümich, Bernhard; Kölker, Christian; Casanova, Federico; Perlo, Juan; Felder, Jörg

    2005-09-01

    An der RWTH Aachen wurde der erste offene und mobile Kernspintomograph entwickelt. Anders als die normalerweise riesigen und unbeweglichen Geräte besitzt er keine enge Magnetröhre. So kann er auch in große Untersuchungsobjekte hinein schauen, ohne dass diese zerstört werden müssen. Wie eine Lupe erfasst er dabei ein begrenztes Volumen um den Aufsatzpunkt herum. Neben der Medizin ermöglicht der offene Tomograph viele neue Anwendungsgebiete, vor allem in der Materialprüfung und Qualitätskontrolle. Der Aachener Prototyp kann auch das Fließprofil und die Geschwindigkeitsverteilung strömender Flüssigkeiten sichtbar machen. Sein offenes Prinzip erforderte neue technische Komponenten und modifizierte bildgebende Verfahren. Die Messzeit pro Bild kann heute schon unter einer Viertelstunde liegen.

  5. Die chronische venöse Insuffizienz - Eine Zusammenfassung der Pathophysiologie, Diagnostik und Therapie.

    PubMed

    Santler, Bettina; Goerge, Tobias

    2017-05-01

    Die chronische Venenerkrankung ist eine weit verbreitete Krankheit, die in späteren Stadien mit einer Vielzahl an Symptomen, aber auch Komplikationen wie dem Ulcus cruris, einhergeht. Dies wiederum hat weitreichende Auswirkungen auf die Lebensqualität der Patienten wie auch auf das Gesundheitssystem. Für die Diagnostik der chronischen Venenerkrankungen steht eine Auswahl an Verfahren zur Verfügung, wobei sich die farbkodierte Duplexsonographie als Goldstandard etabliert hat. Im Bereich der Therapie kam es in den letzten Jahrzehnten zu großen Fortschritten, sodass heute auch Alternativen zum klassischen Stripping durch die endoluminalen Verfahren zur Verfügung stehen. Die Wahl der Therapieoption ist jedoch weiterhin stark abhängig von mehreren Faktoren, unter anderem von den anatomischen Gegebenheiten und dem Krankheitsstadium. Im folgenden Artikel werden die Anatomie und Pathophysiologie, sowie die aktuellen Standards der Diagnostik und Therapie zusammengefasst. © 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  6. Variationeller Ansatz für eine integrierte Segmentierung und nicht-lineare Registrierung

    NASA Astrophysics Data System (ADS)

    Schmidt-Richberg, Alexander; Ehrhardt, Jan; Handels, Heinz

    Vierdimensionale tomographische Bilddaten ermöglichen neuartige Therapie- und Diagnoseverfahren in der medizinischen Praxis. Voraussetzung dafür sind oft die räumlich-zeitliche Segmentierung anatomischer Strukturen in den 4D- Daten und die Bestimmung ihrer dynamischen Eigenschaften durch Schätzung der 3D-Bewegungsfelder mittels nicht-linearer Registrierungsverfahren. In dieser Arbeit wird ein Ansatz vorgestellt, mit dem sich Level-Set-Segmentierung und diffusive, nicht-lineare Registrierung unter Berücksichtigung ihrer wechelseitigen Abhängigkeiten integriert lösen lassen. Die Aufgabe wird als Energieminimierung formuliert und ein variationelles Lösungsverfahren angegeben. Anschließend wird der Ansatz an Phantom- und CT-Patientendaten am Beispiel der Leber validiert.

  7. Toolmanagement - Werkzeuge und Prozesse als Schlüssel für eine effiziente Produktion

    NASA Astrophysics Data System (ADS)

    Enßle, Magnus

    In Bezug auf die Fertigungskosten nehmen die Werkzeugkosten mit 3% einen sehr kleinen und daher vermeintlich unwichtigen Posten ein. HoheKosten ergeben sich aber meist indirekt durch Maschinenstillstandszeiten wegen fehlender oder falscher Werkzeuge, wegen ineffektiven Rüstvorgängen, umständlicher Werkzeuglogistik, unnötig hoher Bestände, unabgestimmter Abläufe, nicht aktueller Fertigungsunterlagen sowie mangelhafter Informationsflüsse zwischen Planung, Vorbereitung und Ausführung in der Fertigung [1].

  8. Ustekinumab in der Therapie der Pustulosis palmoplantaris - Eine Fallserie mit neun Patienten.

    PubMed

    Buder, Valeska; Herberger, Katharina; Jacobi, Arnd; Augustin, Matthias; Radtke, Marc Alexander

    2016-11-01

    Die Pustulosis palmoplantaris ist eine chronisch entzündliche Hauterkrankung, die mit bedeutenden Einschränkungen der Lebensqualität und der Belastbarkeit einhergeht. Aufgrund von Zulassungsbeschränkungen und einem häufig therapierefraktären Verlauf sind die Behandlungsmöglichkeiten limitiert. Nach zuvor frustranen Therapien erhielten 9 Patienten mit Pustulosis palmoplantaris nach Ausschluss einer latenten Tuberkulose Ustekinumab (45 mg Ustekinumab bei < 100 kg Körpergewicht [KG], 90 mg Ustekinumab > 100 kg KG) in Woche 0, 4, 12 und 24. Reguläre Visiten erfolgten nach 4 und 12 Wochen, im weiteren Verlauf alle 12 Wochen. Das Durchschnittsalter bei Therapiebeginn betrug 48 Jahre. Drei Patienten waren männlich. Bei n  =  4 Patienten (44,4 %) wurde eine Verbesserung um 75 % des Palmoplantar-Psoriasis-Area-Severity-Index (PPPASI) erreicht. Insgesamt verbesserte sich der PPPASI nach 24 Wochen durchschnittlich um 71,6 %. Eine komplette Abheilung zeigte sich bei n  =  2 Patienten nach 24 Wochen. Bis auf lokale Injektionsreaktionen und leichte Infekte wurden keine unerwünschten Wirkungen beobachtet. Die Fallserie ist ein weiterer Beleg für die Wirksamkeit und Verträglichkeit von Ustekinumab in der Therapie der Pustulosis palmoplantaris. Zur Beurteilung der Langzeitwirkung und -sicherheit sowie der Wirksamkeit einer intermittierenden Therapie sind kontrollierte Studiendaten sowie Beobachtungen im Rahmen von Patientenregistern notwendig. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  9. Pax2 expression in simultaneously diagnosed WHO and EIN classification systems.

    PubMed

    Joiner, Amy K; Quick, Charles M; Jeffus, Susanne K

    2015-01-01

    PAX2 has been cited as a technically robust biomarker which nicely delineates precancerous lesions of the endometrium when the endometrial intraepithelial neoplasia (EIN) classification scheme is used. Its utility in distinguishing between atypical and nonatypical hyperplasia when applied within the 1994 World Health Organization classification system is questionable. The purpose of this study was to evaluate PAX2 in a side by side comparison of its staining patterns in a series of endometrial samples that were classified using both systems. A total of 108 precancerous endometrial cases were identified, of which 30 cases were deemed nonhyperplastic by consensus agreement and 11 cases lost the tissue of interest on deeper sections. The remaining 67 cases were categorized according to the 1994 World Health Organization criteria and EIN scheme by 2 gynecologic pathologists. PAX2 staining was scored in lesional tissue as normal or altered (lost, increased, or decreased) compared with nonlesional background. The most common pattern of alteration was complete loss of nuclear PAX2 staining (86.3%) followed by decreased staining (11.3%) and markedly increased staining (2.3%). PAX2 alterations correlated well with EIN diagnoses (33/36, 92%) compared with benign hyperplasia (2/13, 15%) but were less useful when the 1994 World Health Organization classification system was applied (PAX2 alteration in 22/25 (88%) of atypical hyperplasia cases versus 16/25 (64%) of nonatypical hyperplasia cases). Forty-five percent of follow-up hysterectomies with a previous PAX2-altered biopsy case harbored adenocarcinoma. In conclusion, PAX2 may be a helpful adjunct stain and training tool when the features of atypical hyperplasia/EIN are in question.

  10. Antikollisionssystem PRORETA - Integrierte Lösung für ein unfallvermeidendes Fahrzeug

    NASA Astrophysics Data System (ADS)

    Isermann, Rolf; Bender, Eva; Bruder, Ralph; Darms, Michael; Schorn, Matthias; Stählin, Ulrich; Winner, Hermann

    Dank einer zunehmenden Verbreitung von aktiven und passiven Sicherheitssystemen in Kraftfahrzeugen konnte die Zahl der Verkehrstoten in den letzten Jahren stetig gesenkt werden. Bei der Bearbeitung des Projekts PRORETA wurde mit der Entwicklung eines elektronischen Fahrerassistenzsystems zur Unfallvermeidung das Ziel verfolgt, durch Notbremsen und Notausweichen Unfälle zu vermeiden. Das System wurde an der TU Darmstadt in Kooperation mit der Continental AG entwickelt. Im Folgenden werden die Grundlagen des Systems, Fahrversuche und Ergebnisse einer ergonomischen Studie dargestellt.

  11. Unsere Sonne - ein rätselhafter Stern? Erkenntnisse und Spekulationen der Astrophysik.

    NASA Astrophysics Data System (ADS)

    Gribbin, J.

    This book is a German translation, by A. Ehlers, of the English original "Blinded by the light. The secret life of the Sun", published in 1991. Contents: 1. Vorgeschichte. 2. Quelle gewaltiger Energien. 3. Im Innern der Sonne. 4. Zuwenig Geister. 5. Ein verrückter Gedanke. 6. Die atmende Sonne. 7. Die zitternde Sonne. 8. Das Große und das Kleine. 9. Der Beitrag der Supernova.

  12. Die histologischen Typen der lymphomatoiden Papulose - Ein Vorschlag für die Vereinfachung des Buchstabenchaos.

    PubMed

    Kempf, Werner; Mitteldorf, Christina; Karai, Laszlo J; Robson, Alistair

    2017-04-01

    Die lymphomatoide Papulose (LYP) ist klinisch durch rezidivierende papulonoduläre Läsionen charakterisiert. Im Gegensatz zu dieser stereotypen klinischen Präsentation zeigt die Erkrankung ein breites histologisches Spektrum mit verschiedenen Infiltratmustern, unterschiedlichen Tumorzellgrößen und variablen Phänotypen. Die revidierte WHO-Klassifikation 2016 umfasst die histologischen LYP-Typen A bis E und einen sechsten Typ, dem eine spezielle Mutation zugrunde liegt. Darüber hinaus werden jedoch immer wieder neue Typen vorgeschlagen, wobei sich die Ausweitung nicht ausschließlich auf histologische Muster bezieht, sondern sich auch auf klinische und genetische Aspekte ausdehnt. Dies führt zu einer Ausweitung der alphabetischen Liste mit zunehmender Komplexität der Terminologie und kann anstelle eines vereinfachten diagnostischen Zugangs zur Verwirrung führen. Zudem kann es zu Überschneidungen unterschiedlicher Typen kommen. Diese Entwicklung wirft die Frage auf, wie die Terminologie der lymphomatoiden Papulose vereinfacht werden kann, ohne dabei auf die histologischen Besonderheiten zu verzichten. Wir schlagen daher einen praktischen Zugang zur Terminologie der lymphomatoide Papulosen vor, welcher sich ausschließlich auf deskriptive Begriffe beschränkt und nicht auf einer alphabetischen Bezeichnung der LYP-Typen beruht. Unser Vorschlag soll einen praktikablen und benutzerfreundlichen Zugang zur Terminologie der lymphomatoiden Papulose ermöglichen und damit den diagnostischen Prozess sowie die Kommunikation zwischen Klinikern und Pathologen vereinfachen. © 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  13. Untersuchung der Richtwirkung der Einkopplung von ebenen Wellen in eine Leitung

    NASA Astrophysics Data System (ADS)

    Magdowski, M.; Vick, R.

    2013-07-01

    Elektrische Leitungen und Kabel stellen häufig die Haupteinfallstore für elektromagnetische Felder in die daran angeschlossenen Geräte und Systeme dar. Für die Einkopplung einer ebenen Welle kann der in eine Leitung eingekoppelte Strom unter bestimmten Voraussetzungen mit Hilfe der Leitungstheorie sehr effizient bestimmt werden. Er hängt dabei von den Abmessungen der Leitung, den Leitungsabschlüssen sowie der Amplitude, der Wellenlänge und der Einfallsrichtung der ebenen Welle ab. In dieser Arbeit wird die Abhängigkeit der Einkopplung von der Einfallsrichtung näher untersucht. Dazu werden Richtdiagramme der Einkopplung berechnet, dargestellt und hinsichtlich der mittleren und maximalen Einkopplung über alle Einfallsrichtungen und Polarisationen ausgewertet. Die Ergebnisse werden genutzt, um die maximale Direktivität der Einkopplung in eine Leitung zu bestimmen. Fasst man die Einkopplung externer Felder in eine Leitung als einen Störfestigkeitstest auf, so kann die maximale Direktivität benutzt werden, um einen Vergleich zwischen unterschiedlichen Messumgebungen wie Absorberhallen und Modenverwirbelungskammern herzustellen.

  14. Isolate PM1 populations are dominant and novel methyl tert-butyl ether-degrading bacterial in compost biofilter enrichments.

    PubMed

    Bruns, M A; Hanson, J R; Mefford, J; Scow, K M

    2001-03-01

    The gasoline additive MTBE, methyl tert-butyl ether, is a widespread and persistent groundwater contaminant. MTBE undergoes rapid mineralization as the sole carbon and energy source of bacterial strain PM1, isolated from an enrichment culture of compost biofilter material. In this report, we describe the results of microbial community DNA profiling to assess the relative dominance of isolate PM1 and other bacterial strains cultured from the compost enrichment. Three polymerase chain reaction (PCR)-based profiling approaches were evaluated: denaturing gradient gel electrophoresis (DGGE) analysis of 230 bp 16S rDNA fragments; thermal gradient gel electrophoresis (TGGE) analysis of 575 bp 16S rDNA fragments; and non-denaturing polyacrylamide gel electrophoresis of 300-1,500 bp fragments containing 16S/23S ribosomal intergenic transcribed spacer (ITS) regions. Whereas all three DNA profiling approaches indicated that PM1-like bands predominated in mixtures from MTBE-grown enrichments, ITS profiling provided the most abundant and specific sequence data to confirm strain PM1's presence in the enrichment. Moreover, ITS profiling did not produce non-specific PCR products that were observed with T/DGGE. A further advantage of ITS community profiling over other methods requiring restriction digestion (e.g. terminal restriction fragment length polymorphisms) was that it did not require an additional digestion step or the use of automated sequencing equipment. ITS bands, excised from similar locations in profiles of the enrichment and PM1 pure culture, were 99.9% identical across 750 16S rDNA positions and 100% identical across 691 spacer positions. BLAST comparisons of nearly full-length 16S rDNA sequences showed 96% similarity between isolate PM1 and representatives of at least four different genera in the Leptothrix subgroup of the beta-Proteobacteria (Aquabacterium, Leptothrix, Rubrivivax and Ideonella). Maximum likelihood and parsimony analyses of 1,249 nucleotide

  15. The Interplay of Chromatin Landscape and DNA-Binding Context Suggests Distinct Modes of EIN3 Regulation in Arabidopsis thaliana

    PubMed Central

    Zemlyanskaya, Elena V.; Levitsky, Victor G.; Oshchepkov, Dmitry Y.; Grosse, Ivo; Mironova, Victoria V.

    2017-01-01

    The plant hormone ethylene regulates numerous developmental processes and stress responses. Ethylene signaling proceeds via a linear pathway, which activates transcription factor (TF) EIN3, a primary transcriptional regulator of ethylene response. EIN3 influences gene expression upon binding to a specific sequence in gene promoters. This interaction, however, might be considerably affected by additional co-factors. In this work, we perform whole genome bioinformatics study to identify the impact of epigenetic factors in EIN3 functioning. The analysis of publicly available ChIP-Seq data on EIN3 binding in Arabidopsis thaliana showed bimodality of distribution of EIN3 binding regions (EBRs) in gene promoters. Besides a sharp peak in close proximity to transcription start site, which is a common binding region for a wide variety of TFs, we found an additional extended peak in the distal promoter region. We characterized all EBRs with respect to the epigenetic status appealing to previously published genome-wide map of nine chromatin states in A. thaliana. We found that the implicit distal peak was associated with a specific chromatin state (referred to as chromatin state 4 in the primary source), which was just poorly represented in the pronounced proximal peak. Intriguingly, EBRs corresponding to this chromatin state 4 were significantly associated with ethylene response, unlike the others representing the overwhelming majority of EBRs related to the explicit proximal peak. Moreover, we found that specific EIN3 binding sequences predicted with previously described model were enriched in the EBRs mapped to the chromatin state 4, but not to the rest ones. These results allow us to conclude that the interplay of genetic and epigenetic factors might cause the distinct modes of EIN3 regulation. PMID:28119721

  16. Treatment of waste gas from the breather vent of a vertical fixed roof p-xylene storage tank by a trickle-bed air biofilter.

    PubMed

    Chang, Shenteng; Lu, Chungsying; Hsu, Shihchieh; Lai, How-Tsan; Shang, Wen-Lin; Chuang, Yeong-Song; Cho, Chi-Huang; Chen, Sheng-Han

    2011-01-01

    This study applied a pilot-scale trickle-bed air biofilter (TBAB) system for treating waste gas emitted from the breather vent of a vertical fixed roof storage tank containing p-xylene (p-X) liquid. The volatile organic compound (VOC) concentration of the waste gas was related to ambient temperature as well as solar radiation, peaking at above 6300 ppmv of p-X and 25000 ppmv of total hydrocarbons during the hours of 8 AM to 3 PM. When the activated carbon adsorber was employed as a VOC buffer, the peak waste gas VOC concentration was significantly reduced resulting in a stably and efficiently performing TBAB system. The pressure drop appeared to be low, reflecting that the TBAB system could be employed in the prolonged operation with a low running penalty. These advantages suggest that the TBAB system is a cost-effective treatment technology for VOC emission from a fixed roof storage tank.

  17. Application and advantages of novel clay ceramic particles (CCPs) in an up-flow anaerobic bio-filter (UAF) for wastewater treatment.

    PubMed

    Han, Wei; Yue, Qinyan; Wu, Suqing; Zhao, Yaqin; Gao, Baoyu; Li, Qian; Wang, Yan

    2013-06-01

    Utilization of clay ceramic particles (CCPs) as the novel filter media employed in an up-flow anaerobic bio-filter (UAF) was investigated. After a series of tests and operations, CCPs have presented higher total porosity and roughness, meanwhile lower bulk and grain density. When CCPs were utilized as fillers, the reactor had a shorter start up period of 45 days comparing with conventional reactors, and removal rate of chemical oxygen demand (COD) still reached about 76% at a relatively lower temperature during the stable state. In addition, degradation of COD and ammonia nitrogen (NH4-N) at different media height along the reactor was evaluated, and the dates showed that the main reduction process happened within the first 30 cm media height from the bottom flange. Five phases were observed according to different organic loadings during the experiment period, and the results indicated that COD removal increased linearly when the organic loading was increased.

  18. Differentiation of Gram-Negative, Nonfermentative Bacteria Isolated from Biofilters on the Basis of Fatty Acid Composition, Quinone System, and Physiological Reaction Profiles

    PubMed Central

    Lipski, André; Klatte, Stefan; Bendinger, Bernd; Altendorf, Karlheinz

    1992-01-01

    Gram-negative, nonfermentative bacteria isolated from biofilters for off-gas treatment of animal-rendering-plant emissions were differentiated by whole-cell fatty acid analysis, quinone analysis, and numerical taxonomy based on their physiological reaction profiles. The last system consisted of 60 physiological tests and was arranged as a microtest system on microtitration plates. Based on fatty acid analyses, 31 isolates were separated into six clusters and five single-member clusters. The isolates of two clusters were identified as Alcaligenes faecalis and Pseudomonas diminuta. The remaining nine clusters were characterized by their fatty acid profiles, quinone systems, and physiological reaction profiles. Clusters resulting from fatty acid analyses were compared with those resulting from physiological reaction profiles. Six clusters could be confirmed this way. The efficiency of the physiological test system was increased by the prearrangement of the isolates according to their quinone type. PMID:16348724

  19. Aquaculture solids management using a combination of sand/gravel or unwoven fabric bed with Lolium perenne Lam as a plant biofilter.

    PubMed

    Nduwimana, André; Yang, Xiang-Long; Wang, Li-Ren

    2007-12-01

    This work is an evaluation of the efficiency of a sand-gravel or unwoven fabric bed system and Lolium perenne Lam as plant biofilter in the reduction of solids and nutrients removal from aquaculture discharge water. The first step consisted of the collection of wastewater in the tank and the distribution at three different hydraulic loading regimes (0.5, 1, 1.5 L/hour) to the different experimental systems. The second step was to evaluate the performance of the different systems. The first system consisted of a bucket filled with a substrate of sand/gravel (20 cm in depth), on the bottom of which was a 80 mesh/inch2 of nylon (S1); the second was similar, but was planted with Lolium perenne lam (S2); the third was planted with a grass plate consisting of 7 layers of unwoven fabric planted with L perenne (S3). The second system showed the best performance in reducing solids as well as in nutrients (TN, TP, and COD) reduction. The removal rates for TS, TN, and TP were negatively correlated with the loading regimes, with 0.5 L/hour being the most efficient and thus taken as the reference. Solids management using a sand/gravel substrate as bed culture and Lolium perenne L. as plant biofilter has proved to be an efficient technique for solids reduction with low operating cost. This grass plays an important role in wastewater eco-treatment by absorbing dissolved pollutants (TAN) as nutrients for its growth.

  20. Denitrification and biofilm growth in a pilot-scale biofilter packed with suspended carriers for biological nitrogen removal from secondary effluent.

    PubMed

    Shi, Yunhong; Wu, Guangxue; Wei, Nan; Hu, Hongying

    2015-06-01

    Tertiary denitrification is an effective method for nitrogen removal from wastewater. A pilot-scale biofilter packed with suspended carriers was operated for tertiary denitrification with ethanol as the organic carbon source. Long-term performance, biokinetics of denitrification and biofilm growth were evaluated under filtration velocities of 6, 10 and 14 m/hr. The pilot-scale biofilter removed nitrate from the secondary effluent effectively, and the nitrate nitrogen (NO3-N) removal percentage was 82%, 78% and 55% at the filtration velocities of 6, 10 and 14 m/hr, respectively. At the filtration velocities of 6 and 10 m/hr, the nitrate removal loading rate increased with increasing influent nitrate loading rates, while at the filtration velocity of 14 m/hr, the removal loading rate and the influent loading rate were uncorrelated. During denitrification, the ratio of consumed chemical oxygen demand to removed NO3-N was 3.99-4.52 mg/mg. Under the filtration velocities of 6, 10 and 14 m/hr, the maximum denitrification rate was 3.12, 4.86 and 4.42 g N/(m2·day), the half-saturation constant was 2.61, 1.05 and 1.17 mg/L, and the half-order coefficient was 0.22, 0.32 and 0.24(mg/L)1/2/min, respectively. The biofilm biomass increased with increasing filtration velocity and was 2845, 5124 and 7324 mg VSS/m2 at filtration velocities of 6, 10 and 14 m/hr, respectively. The highest biofilm density was 44 mg/cm3 at the filtration velocity of 14 m/hr. Due to the low influent loading rate, biofilm biomass and thickness were lowest at the filtration velocity of 6m/hr. Copyright © 2015. Published by Elsevier B.V.

  1. ETHYLENE-INSENSITIVE5 encodes a 5'-->3' exoribonuclease required for regulation of the EIN3-targeting F-box proteins EBF1/2.

    PubMed

    Olmedo, Gabriela; Guo, Hongwei; Gregory, Brian D; Nourizadeh, Saeid D; Aguilar-Henonin, Laura; Li, Hongjiang; An, Fengying; Guzman, Plinio; Ecker, Joseph R

    2006-09-05

    Ethylene is a gaseous plant growth regulator that controls a multitude of developmental and stress responses. Recently, the levels of Arabidopsis EIN3 protein, a key transcription factor mediating ethylene-regulated gene expression, have been demonstrated to increase in response to the presence of ethylene gas. Furthermore, in the absence of ethylene, EIN3 is quickly degraded through a ubiquitin/proteasome pathway mediated by two F-box proteins, EBF1 and EBF2. Here we report the identification of ETHYLENE-INSENSITIVE5 as the 5'-->3' exoribonuclease XRN4. Specifically, we demonstrate that EIN5 is a component of the ethylene signal transduction cascade acting downstream of CTR1 that is required for ethylene-mediated gene expression changes. Furthermore, we find that the ethylene insensitivity of ein5 mutant plants is a consequence of the over-accumulation of EBF1 and EBF2 mRNAs resulting in the under-accumulation of EIN3 even in the presence of ethylene gas. Together, our results suggest that the role of EIN5 in ethylene perception is to antagonize the negative feedback regulation on EIN3 by promoting EBF1 and EBF2 mRNA decay, which consequently allows the accumulation of EIN3 protein to trigger the ethylene response.

  2. EIN2-dependent regulation of acetylation of histone H3K14 and non-canonical histone H3K23 in ethylene signalling

    PubMed Central

    Zhang, Fan; Qi, Bin; Wang, Likai; Zhao, Bo; Rode, Siddharth; Riggan, Nathaniel D.; Ecker, Joseph R.; Qiao, Hong

    2016-01-01

    Ethylene gas is essential for many developmental processes and stress responses in plants. EIN2 plays a key role in ethylene signalling but its function remains enigmatic. Here, we show that ethylene specifically elevates acetylation of histone H3K14 and the non-canonical acetylation of H3K23 in etiolated seedlings. The up-regulation of these two histone marks positively correlates with ethylene-regulated transcription activation, and the elevation requires EIN2. Both EIN2 and EIN3 interact with a SANT domain protein named EIN2 nuclear associated protein 1 (ENAP1), overexpression of which results in elevation of histone acetylation and enhanced ethylene-inducible gene expression in an EIN2-dependent manner. On the basis of these findings we propose a model where, in the presence of ethylene, the EIN2 C terminus contributes to downstream signalling via the elevation of acetylation at H3K14 and H3K23. ENAP1 may potentially mediate ethylene-induced histone acetylation via its interactions with EIN2 C terminus. PMID:27694846

  3. Endometrial Intraepithelial Neoplasia (EIN) in endometrial biopsy specimens categorized by the 1994 World Health Organization classification for endometrial hyperplasia.

    PubMed

    Li, Xiao-Chao; Song, Wen-Jing

    2013-01-01

    Our study is to determine the presence of endometrial intraepithelial neoplasia (EIN) in endometrial biopsy specimens classified by the 1994 World Health Organization (WHO) criteria for endometrial hyperplasia. Endometrial biopsy specimens that were stained with hematoxylin and eosin (HE) were examined and categorized by the WHO 1994 criteria and for the presence of EIN as defined by the International Endometrial Collaborative Group. β-catenin expression was examined by immunohistochemistry. A total of 474 cases of HE stained endometrial biopsy tissues were reviewed. There were 379 cases of simple endometrial hyperplasia, 16 with simple atypical endometrial hyperplasia, 48 with complex endometrial hyperplasia, and 31 with complex atypical endometrial hyperplasia. Among the 474 endometrial hyperplasia cases, there were 46 (9.7%) that were classified as EIN. Of these 46 cases, 11(2.9%) were classified as simple endometrial hyperplasia, 1 (6.3%) as simple atypical endometrial hyperplasia, 6 (12.5%) as complex endometrial hyperplasia, and 28 (90.3%) as complex atypical endometrial hyperplasia. EIN was associated with a higher rate of β-catenin positivity than endometrium classified as benign hyperplasia (72% vs. 22.5%, respectively, P < 0.001), but a lower rate than endometrial adenocarcinoma (72% vs. 96.2%, respectively, P < 0.001). In benign endometrial hyperplasia, high β-catenin expression was noted in the cell membranes, whereas in EIN and endometrial adenocarcinoma high expression was noted in the cytoplasm. In conclusion, EIN is more accurate than the WHO classification for the diagnosis of precancerous lesions of the endometrium.

  4. Responses of community structure of amoA-encoding archaea and ammonia-oxidizing bacteria in ammonia biofilter with rockwool mixtures to the gradual increases in ammonium and nitrate.

    PubMed

    Yasuda, T; Waki, M; Kuroda, K; Hanajima, D; Fukumoto, Y; Yamagishi, T; Suwa, Y; Suzuki, K

    2013-03-01

    To investigate community shifts of amoA-encoding archaea (AEA) and ammonia-oxidizing bacteria (AOB) in biofilter under nitrogen accumulation process. A laboratory-scale rockwool biofilter with an irrigated water circulation system was operated for 436 days with ammonia loading rates of 49-63 NH(3) g m(-3) day(-1). The AEA and AOB communities were investigated by denaturing gradient gel electrophoresis, sequencing and real-time PCR analysis based on amoA genes. The results indicated that changes in abundance and community compositions occurred in a different manner between archaeal and bacterial amoA during the operation. However, both microbial community structures mainly varied when free ammonia (FA) concentrations in circulation water were increasing, which caused a temporal decline in reactor performance. Dominant amoA sequences after this transition were related to Thaumarchaeotal Group I.1b, Nitrosomonas europaea lineages and one subcluster within Nitrosospira sp. cluster 3, for archaea and bacteria, respectively. The specific FA in circulation water seems to be the important factor, which relates to the AOB and AEA community shifts in the biofilter besides ammonium and pH. One of the key factors for regulating AEA and AOB communities was proposed that is useful for optimizing biofiltration technology. © 2013 The Society for Applied Microbiology.

  5. EIN3 and ORE1 Accelerate Degreening during Ethylene-Mediated Leaf Senescence by Directly Activating Chlorophyll Catabolic Genes in Arabidopsis.

    PubMed

    Qiu, Kai; Li, Zhongpeng; Yang, Zhen; Chen, Junyi; Wu, Shouxin; Zhu, Xiaoyu; Gao, Shan; Gao, Jiong; Ren, Guodong; Kuai, Benke; Zhou, Xin

    2015-07-01

    Degreening, caused by chlorophyll degradation, is the most obvious symptom of senescing leaves. Chlorophyll degradation can be triggered by endogenous and environmental cues, and ethylene is one of the major inducers. ETHYLENE INSENSITIVE3 (EIN3) is a key transcription factor in the ethylene signaling pathway. It was previously reported that EIN3, miR164, and a NAC (NAM, ATAF, and CUC) transcription factor ORE1/NAC2 constitute a regulatory network mediating leaf senescence. However, how this network regulates chlorophyll degradation at molecular level is not yet elucidated. Here we report a feed-forward regulation of chlorophyll degradation that involves EIN3, ORE1, and chlorophyll catabolic genes (CCGs). Gene expression analysis showed that the induction of three major CCGs, NYE1, NYC1 and PAO, by ethylene was largely repressed in ein3 eil1 double mutant. Dual-luciferase assay revealed that EIN3 significantly enhanced the promoter activity of NYE1, NYC1 and PAO in Arabidopsis protoplasts. Furthermore, Electrophoretic mobility shift assay (EMSA) indicated that EIN3 could directly bind to NYE1, NYC1 and PAO promoters. These results reveal that EIN3 functions as a positive regulator of CCG expression during ethylene-mediated chlorophyll degradation. Interestingly, ORE1, a senescence regulator which is a downstream target of EIN3, could also activate the expression of NYE1, NYC1 and PAO by directly binding to their promoters in EMSA and chromatin immunoprecipitation (ChIP) assays. In addition, EIN3 and ORE1 promoted NYE1 and NYC1 transcriptions in an additive manner. These results suggest that ORE1 is also involved in the direct regulation of CCG transcription. Moreover, ORE1 activated the expression of ACS2, a major ethylene biosynthesis gene, and subsequently promoted ethylene production. Collectively, our work reveals that EIN3, ORE1 and CCGs constitute a coherent feed-forward loop involving in the robust regulation of ethylene-mediated chlorophyll degradation

  6. Arabidopsis thaliana responses to mechanical stimulation do not require ETR1 or EIN2

    NASA Technical Reports Server (NTRS)

    Johnson, K. A.; Sistrunk, M. L.; Polisensky, D. H.; Braam, J.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    Plants exposed to repetitive touch or wind are generally shorter and stockier than sheltered plants. These mechanostimulus-induced developmental changes are termed thigmomorphogenesis and may confer resistance to subsequent stresses. An early response of Arabidopsis thaliana to touch or wind is the up-regulation of TCH (touch) gene expression. The signal transduction pathway that leads to mechanostimulus responses is not well defined. A role for ethylene has been proposed based on the observation that mechanostimulation of plants leads to ethylene evolution and exogenous ethylene leads to thigmomorphogenetic-like changes. To determine whether ethylene has a role in plant responses to mechanostimulation, we assessed the ability of two ethylene-insensitive mutants, etr1-3 and ein2-1, to undergo thigmomorphogenesis and TCH gene up-regulation of expression. The ethylene-insensitive mutants responded to wind similarly to the wild type, with a delay in flowering, decrease in inflorescence elongation rate, shorter mature primary inflorescences, more rosette paraclades, and appropriate TCH gene expression changes. Also, wild-type and mutant Arabidopsis responded to vibrational stimulation, with an increase in hypocotyl elongation and up-regulation of TCH gene expression. We conclude that the ETR1 and EIN2 protein functions are not required for the developmental and molecular responses to mechanical stimulation.

  7. Arabidopsis thaliana responses to mechanical stimulation do not require ETR1 or EIN2

    NASA Technical Reports Server (NTRS)

    Johnson, K. A.; Sistrunk, M. L.; Polisensky, D. H.; Braam, J.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    Plants exposed to repetitive touch or wind are generally shorter and stockier than sheltered plants. These mechanostimulus-induced developmental changes are termed thigmomorphogenesis and may confer resistance to subsequent stresses. An early response of Arabidopsis thaliana to touch or wind is the up-regulation of TCH (touch) gene expression. The signal transduction pathway that leads to mechanostimulus responses is not well defined. A role for ethylene has been proposed based on the observation that mechanostimulation of plants leads to ethylene evolution and exogenous ethylene leads to thigmomorphogenetic-like changes. To determine whether ethylene has a role in plant responses to mechanostimulation, we assessed the ability of two ethylene-insensitive mutants, etr1-3 and ein2-1, to undergo thigmomorphogenesis and TCH gene up-regulation of expression. The ethylene-insensitive mutants responded to wind similarly to the wild type, with a delay in flowering, decrease in inflorescence elongation rate, shorter mature primary inflorescences, more rosette paraclades, and appropriate TCH gene expression changes. Also, wild-type and mutant Arabidopsis responded to vibrational stimulation, with an increase in hypocotyl elongation and up-regulation of TCH gene expression. We conclude that the ETR1 and EIN2 protein functions are not required for the developmental and molecular responses to mechanical stimulation.

  8. Einstellung und Wissen von Lehramtsstudierenden zur Evolution - ein Vergleich zwischen Deutschland und der Türkei

    NASA Astrophysics Data System (ADS)

    Graf, Dittmar; Soran, Haluk

    Es wird eine Untersuchung vorgestellt, in der Wissen und Überzeugungen von Lehramtsstudierenden aller Fächer zum Thema Evolution an zwei Universitäten in Deutschland und der Türkei erhoben worden sind. Die Befragung wurde in Dortmund und in Ankara durchgeführt. Es stellte sich heraus, dass ausgeprägte Defizite im Verständnis der Evolutionsmechanismen herrschen. Viele Studierende, insbesondere aus der Türkei, sind nicht von der Faktizität der Evolution überzeugt. Dies gilt sowohl für Studierende mit Fach Biologie als auch für Studierende mit anderen Fächern. Näher untersucht worden sind die Faktoren, die die Überzeugungen zur Evolution beeinflussen können, was ja in Anbetracht der hohen Ablehnungsrate der Evolution von besonderem Interesse ist. Das Vertrauen in die Wissenschaft spielt hierbei eine besondere Rolle: Wer der Wissenschaft vertraut, ist auch eher von der Evolution überzeugt, als diejenigen, die skeptisch gegenüber der Wissenschaft sind.

  9. EIN3-like gene expression during fruit ripening of Cavendish banana (Musa acuminata cv. Grande naine).

    PubMed

    Mbéguié-A-Mbéguié, Didier; Hubert, Olivier; Fils-Lycaon, Bernard; Chillet, Marc; Baurens, Franc-Christophe

    2008-06-01

    Ethylene signal transduction initiates with ethylene binding at receptor proteins and terminates in a transcription cascade involving the EIN3/EIL transcription factors. Here, we have isolated four cDNAs homologs of the Arabidopsis EIN3/EIN3-like gene, MA-EILs (Musa acuminata ethylene insensitive 3-like) from banana fruit. Sequence comparison with other banana EIL gene already registered in the database led us to conclude that, at this day, at least five different genes namely MA-EIL1, MA-EIL2/AB266318, MA-EIL3/AB266319, MA-EIL4/AB266320 and AB266321 exist in banana. Phylogenetic analyses included all banana EIL genes within a same cluster consisting of rice OsEILs, a monocotyledonous plant as banana. However, MA-EIL1, MA-EIL2/AB266318, MA-EIL4/AB266320 and AB266321 on one side, and MA-EIL3/AB266319 on the other side, belong to two distant subclusters. MA-EIL mRNAs were detected in all examined banana tissues but at lower level in peel than in pulp. According to tissues, MA-EIL genes were differentially regulated by ripening and ethylene in mature green fruit and wounding in old and young leaves. MA-EIL2/AB266318 was the unique ripening- and ethylene-induced gene; MA-EIL1, MA-EIL4/Ab266320 and AB266321 genes were downregulated, while MA-EIL3/AB266319 presented an unusual pattern of expression. Interestingly, a marked change was observed mainly in MA-EIL1 and MA-EIL3/Ab266319 mRNA accumulation concomitantly with changes in ethylene responsiveness of fruit. Upon wounding, the main effect was observed in MA-EIL4/AB266320 and AB266321 mRNA levels, which presented a markedly increase in both young and old leaves, respectively. Data presented in this study suggest the importance of a transcriptionally step control in the regulation of EIL genes during banana fruit ripening.

  10. CTR1 phosphorylates the central regulator EIN2 to control ethylene hormone signaling from the ER membrane to the nucleus in Arabidopsis.

    PubMed

    Ju, Chuanli; Yoon, Gyeong Mee; Shemansky, Jennifer Marie; Lin, David Y; Ying, Z Irene; Chang, Jianhong; Garrett, Wesley M; Kessenbrock, Mareike; Groth, Georg; Tucker, Mark L; Cooper, Bret; Kieber, Joseph J; Chang, Caren

    2012-11-20

    The gaseous phytohormone ethylene C(2)H(4) mediates numerous aspects of growth and development. Genetic analysis has identified a number of critical elements in ethylene signaling, but how these elements interact biochemically to transduce the signal from the ethylene receptor complex at the endoplasmic reticulum (ER) membrane to transcription factors in the nucleus is unknown. To close this gap in our understanding of the ethylene signaling pathway, the challenge has been to identify the target of the CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) Raf-like protein kinase, as well as the molecular events surrounding ETHYLENE-INSENSITIVE2 (EIN2), an ER membrane-localized Nramp homolog that positively regulates ethylene responses. Here we demonstrate that CTR1 interacts with and directly phosphorylates the cytosolic C-terminal domain of EIN2. Mutations that block the EIN2 phosphorylation sites result in constitutive nuclear localization of the EIN2 C terminus, concomitant with constitutive activation of ethylene responses in Arabidopsis. Our results suggest that phosphorylation of EIN2 by CTR1 prevents EIN2 from signaling in the absence of ethylene, whereas inhibition of CTR1 upon ethylene perception is a signal for cleavage and nuclear localization of the EIN2 C terminus, allowing the ethylene signal to reach the downstream transcription factors. These findings significantly advance our understanding of the mechanisms underlying ethylene signal transduction.

  11. Inzidenz von bullösen Autoimmunerkrankungen in Serbien: eine retrospektive Studie über 20 Jahre.

    PubMed

    Milinković, Mirjana; Janković, Slavenka; Medenica, Ljiljana; Nikolić, Miloš; Reljić, Vesna; Popadić, Svetlana; Janković, Janko

    2016-10-01

    Die meisten früheren Arbeiten zu den klinisch-epidemiologischen Merkmalen von bullösen Autoimmunerkrankungen (AIBD) konzentrierten sich vor allem auf eine einzige Krankheitsentität oder nur eine Krankheitsgruppe; nur in wenigen Studien wurde die Inzidenz verschiedener AIBD untersucht. Bei der vorliegenden Studie war es unser Ziel, das gesamte Spektrum der AIBD zu betrachten, die Inzidenz der häufigsten AIBD zu ermitteln und die zeitlichen Trends ihres Auftretens in Zentralserbien über einen Zeitraum von 20 Jahren zu untersuchen. Wir rekrutierten retrospektiv 1161 AIBD-Fälle, die in Zentralserbien von Januar 1991 bis Dezember 2010 neu diagnostiziert wurden. Die Diagnose stützte sich auf eine strikte klinische, histologische und immunhistologische Beurteilung. Folgende Inzidenzraten wurden für die einzelnen Erkrankungen ermittelt: 4,35 pro eine Million Einwohner/Jahr (pME/Jahr) für Pemphigus, 4,47 pME/Jahr für Pemphigoid, 1,42 pME/Jahr für Dermatitis herpetiformis (DH), 0,25 pME/Jahr IgA-Dermatose und 0,08 pME/Jahr für Epidermolysis bullosa acquisita. Im betrachteten Zeitraum stieg die altersbereinigte Inzidenzrate für Pemphigus und insbesondere für Pemphigoid signifikant an, während sie für DH, allerdings nicht signifikant, abnahm. Unsere Studie befasst sich zum ersten Mal mit den Inzidenzraten des gesamten Spektrums der AIBD in Serbien und untersucht die zeitlichen Trends ihres Auftretens über einen Zeitraum von 20 Jahren. Nach unserem besten Wissen wurde ein ähnlicher Befund wie der unsere, dass nämlich die Inzidenzraten von Pemphigus und Pemphigoid vergleichbar sind, bisher noch nicht publiziert. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  12. AtMYB44 regulates resistance to the green peach aphid and diamondback moth by activating EIN2-affected defences in Arabidopsis.

    PubMed

    Lü, B-B; Li, X-J; Sun, W-W; Li, L; Gao, R; Zhu, Q; Tian, S-M; Fu, M-Q; Yu, H-L; Tang, X-M; Zhang, C-L; Dong, H-S

    2013-09-01

    Recently we showed that the transcription activator AtMYB44 regulates expression of EIN2, a gene essential for ethylene signalling and insect resistance, in Arabidopsis thaliana (Arabidopsis). To link the transactivation with insect resistance, we investigated the wild-type and atmyb44 mutant plants, genetically Complemented atmyb44 (Catmyb44) and AtMYB44-Overexpression Transgenic Arabidopsis (MYB44OTA). We found that AtMYB44 played a critical role in Arabidopsis resistance to the phloem-feeding generalist green peach aphid (Myzus persicae Sulzer) and leaf-chewing specialist caterpillar diamondback moth (Plutella xylostella L.). AtMYB44 was required not only for the development of constitutive resistance but also for the induction of resistance by both herbivorous insects. Levels of constitutive and herbivore-induced resistance were consistent with corresponding amounts of the AtMYB44 protein constitutively produced in MYB44OTA and induced by herbivory in Catmyb44. In both cases, AtMYB44 promoted EIN2 expression to a greater extent in MYB44OTA than in Catmyb44. However, AtMYB44-promoted EIN2 expression was arrested with reduced resistance levels in the EIN2-deficient Arabidopsis mutant ein2-1 and the MYB44OTA ein2-1 hybrid. In the different plant genotypes, only MYB44OTA constitutively displayed phloem-based defences, which are specific to phloem-feeding insects, and robust expression of genes involved in the biosynthesis of glucosinolates, which are the secondary plant metabolites known as deterrents to generalist herbivores. Phloem-based defences and glucosinolate-related gene expression were not detected in ein2-1 and MYB44OTA ein2-1. These results establish a genetic connection between the regulatory role of AtMYB44 in EIN2 expression and the development of Arabidopsis resistance to insects.

  13. Effects of pollutant concentration ratio on the simultaneous removal of NH3, H2S and toluene gases using rock wool-compost biofilter.

    PubMed

    Galera, Melvin Maaliw; Cho, Eulsaeng; Tuuguu, Enkhdul; Park, Shin-Jung; Lee, Changhee; Chung, Wook-Jin

    2008-04-01

    The biological treatment of a tri-component mixed waste gas system in BRC1 and BRC2 biofilters packed with rock wool-compost media was studied. The model gases were NH(3), H(2)S and toluene. The gases were fed initially at about 50-55 ppm each. H(2)S was found to have the shortest start-up while toluene had the longest. Under two different NH(3):H(2)S:toluene concentration ratios of 250:120:55 and 120:220:55 (in ppm) for BRC1 and BRC2, the removal efficiencies of NH(3), H(2)S and toluene were found to be affected by their respective loading rate. On the other hand, toluene removal was observed to be inhibited at H(2)S concentration of 220 ppm as well. Almost complete removal of NH(3) and H(2)S was achieved when loading rate was applied up to 16.14 g-NH(3)/(m(3) bed h) and 36.09 g-H(2)S/(m(3) bed h), respectively. The maximum elimination capacity for NH(3) was determined to be 23.67 g-NH(3)/(m(3) bed h) at 78.6% removal efficiency and for H(2)S, 38.50 g-H(2)S/(m(3) bed h) at 68.1% removal efficiency. The maximum toluene elimination capacity was 30.75 g-toluene/(m(3) bed h) at 87.9% removal efficiency when the concentration of NH(3):H(2)S:toluene was 250:120:55 in BRC1, and was 16.60 g-toluene/(m(3) bed h) at 45.5% removal efficiency when the concentration of NH(3):H(2)S:toluene was 120:220:55 in BRC2. The pressure drops along both columns were low and the ratio of bed compactions over biofilter height was observed to be less than 0.02.

  14. NEXT-GENERATION ANALYSIS OF CATARACTS: DETERMINING KNOWLEDGE DRIVEN GENE-GENE INTERACTIONS USING BIOFILTER, AND GENE-ENVIRONMENT INTERACTIONS USING THE PHENX TOOLKIT*

    PubMed Central

    Pendergrass, Sarah A.; Verma, Shefali S.; Holzinger, Emily R.; Moore, Carrie B.; Wallace, John; Dudek, Scott M.; Huggins, Wayne; Kitchner, Terrie; Waudby, Carol; Berg, Richard; McCarty, Catherine A.; Ritchie, Marylyn D.

    2013-01-01

    Investigating the association between biobank derived genomic data and the information of linked electronic health records (EHRs) is an emerging area of research for dissecting the architecture of complex human traits, where cases and controls for study are defined through the use of electronic phenotyping algorithms deployed in large EHR systems. For our study, 2580 cataract cases and 1367 controls were identified within the Marshfield Personalized Medicine Research Project (PMRP) Biobank and linked EHR, which is a member of the NHGRI-funded electronic Medical Records and Genomics (eMERGE) Network. Our goal was to explore potential gene-gene and gene-environment interactions within these data for 529,431 single nucleotide polymorphisms (SNPs) with minor allele frequency > 1%, in order to explore higher level associations with cataract risk beyond investigations of single SNP-phenotype associations. To build our SNP-SNP interaction models we utilized a prior-knowledge driven filtering method called Biofilter to minimize the multiple testing burden of exploring the vast array of interaction models possible from our extensive number of SNPs. Using the Biofilter, we developed 57,376 prior-knowledge directed SNP-SNP models to test for association with cataract status. We selected models that required 6 sources of external domain knowledge. We identified 5 statistically significant models with an interaction term with p-value < 0.05, as well as an overall model with p-value < 0.05 associated with cataract status. We also conducted gene-environment interaction analyses for all GWAS SNPs and a set of environmental factors from the PhenX Toolkit: smoking, UV exposure, and alcohol use; these environmental factors have been previously associated with the formation of cataracts. We found a total of 288 models that exhibit an interaction term with a p-value ≤ 1×10−4 associated with cataract status. Our results show these approaches enable advanced searches for epistasis

  15. A comparative study by electron paramagnetic resonance of free radical species in the mainstream and sidestream smoke of cigarettes with conventional acetate filters and 'bio-filters'.

    PubMed

    Valavanidis, A; Haralambous, E

    2001-01-01

    Tobacco smoking is the most important extrinsic cause, after the diet, for increasing morbidity and mortality in humans. Unless current tobacco smoking patterns in industrialised and non-industrialised countries change, cigarettes will kill prematurely 10 million people a year by 2025. Greece is at the top of the list of European countries in cigarette consumption. In 1997, a Greek tobacco company introduced a new 'bio-filter' (BF) claiming that it reduces substantially the risks of smoking. In a recent publication [Deliconstantinos G, Villiotou V, Stavrides J. Scavenging effects of hemoglobin and related heme containing compounds on nitric oxide, reactive oxidants and carcinogenic volatile nitrosocompounds of cigarette smoke. A new method for protection against the dangerous cigarette constituents. Anticancer Res 1994; 14: 2717-2726] it was claimed that the new 'bio-filter' (activated carbon impregnated with dry hemoglobin) reduces certain toxic substances and oxidants (like NO, CO, NOx, H2O2, aldehydes, trace elements and nitroso-compounds) in the gas-phase of the mainstream smoke. We have investigated by electron paramagnetic resonance (EPR) the mainstream and sidestream smoke of the BF cigarette, in comparison with three other cigarettes with similar tar and nicotine contents, that have conventional acetate filters. We found that BF cigarette smoke has similar tar radical species with the same intensity EPR signals to those of the other cigarettes. The ability of the aqueous cigarette tar extracts to produce hydroxyl radicals (HO*), which were spin trapped by DMPO, was very similar to, or even higher than, the other 3 brands. The gas-phase of the mainstream smoke of the BF cigarette showed a 30-35% reduction in the production of oxygen-centered radicals (spin trapped with PBN). In the case of the sidestream smoke, BF cigarettes produced substantially higher concentrations of gas-phase radicals, compared to the other brands. These results suggest that BF is

  16. Soil mycoflora from the Dead Sea Oases of Ein Gedi and Einot Zuqim (Israel).

    PubMed

    Steiman, R; Guiraud, P; Sage, L; Seigle-Murandi, F

    1997-10-01

    Samples were taken from the top 10 cm of soils from 24 points in the Ein Gedi area. Among 329 isolates, 142 species were identified: 11 genera of ascomycetes, one genus of coelomycetes, 28 genera of hyphomycetes, 7 genera of zygomycetes and one yeast, in addition to some unidentified basidiomycetes. The hyphomycetes were represented by 17 dematiaceous, 9 mucedinaceous and two tuberculariaceous. Melanconiaceous and stilbellaceous genera were not found. Two new varieties of Microascus recently described were reisolated. No strict thermophiles or halophiles were obtained. There is apparently no very characteristic or specific fungal flora of the Dead Sea Oases although it was different from that found in the desert soil surrounding this area.

  17. [Investigation of effect and process of nitric oxide removal in rotating drum biofilter coupled with absorption by Fe(II) (EDTA)].

    PubMed

    Chen, Jun; Yang, Xuan; Yu, Jian-Ming; Jiang, Yi-Feng; Chen, Jian-Meng

    2012-02-01

    In order to accelerate the NO removal efficiency, a novel and effective system was developed for the complete treatment of NO from flue gases. The system features NO absorption by Fe(II) (EDTA) and biological denitrification in a rotating drum biofilter (RDB) so as to promote biological reduction. The experimental results show that a moderate amount of Fe(II) (EDTA) was added to the nutrient solution to improve the mass transfer efficiency of NO from gas to liquid, with the concomitant formation of nitrosyl complex Fe(II) (EDTA)-NO. Under the experimental conditions of rotational speed was at 0.5 r x min(-1), EBRT of 57.7 s, temperature was at 30 degrees C, pH was 7-8, with the increasing concentration of Fe(II) (EDTA) was from 0 mg x L(-1) to 500 mg x L(-1), the NO removal efficiency was improved from 61.1% to 97.6%, and the elimination capacity was from 16.2 g (m3 x h)(-1) to 26.7 g (m3 x h)(-1). In order to simulate the denitrifying process of waste gas containing NO by using RDB coupled with Fe(II) (EDTA) absorption, a tie-in equation of NO removal and the Fe(II) (EDTA) concentration added in RDB was established. The experimental NO removal efficiency change tendency agrees fairly with that predicted by the proposed equation.

  18. Dreissena polymorpha (Bivalvia: Dreissenidae) in the Neva Estuary (eastern Gulf of Finland, Baltic Sea): is it a biofilter or source for pollution?

    PubMed

    Orlova, M; Golubkov, S; Kalinina, L; Ignatieva, N

    2004-08-01

    The zebra mussel Dreissena polymorpha, a ponto-caspian byssate bivalve, forms permanent dense populations along the shoreline in the northern part of the inner Neva Estuary. Its total biomass along a 17 km transect reached 4980 tons (mean 1060 g m(-2)) in 2000 and 6510 tons (mean 1385 g m(-2)) in 2001. Being persistent and abundant, the zebra mussel populations played an important role in benthic-pelagic coupling in inner Neva River Estuary. The D. polymorpha population released up to 514 kg day(-1) of dissolved inorganic phosphorus and was, therefore, a major source of bioavailable nutrients in the area. Mussel beds were also efficient biofilters and precipitate 15,020 kg day(-1) of particulate organic matter during the warm season. About 50% of precipitated matter had a relatively long retention time, being utilized within zebra mussel populations, while the rest was deposited as faeces and pseudofaeces and served as a source for organic pollution to the eastern Gulf of Finland.

  19. Enhanced long-term ammonium removal and its ranked contribution of microbial genes associated with nitrogen cycling in a lab-scale multimedia biofilter.

    PubMed

    Wang, Honglei; Ji, Guodong; Bai, Xueyuan

    2015-11-01

    The multimedia biofilter achieved high and stable removal efficiencies for chemical oxygen demand (COD, 62-98%) and NH4(+) (68-98%) without costly aeration. Results revealed that lower CL (less than 13.9gCOD/m(3)d) and ACL (less than 2.8gNH4(+)-N/m(3)d) or a C/N ratio exceeding five was required to reduce NO3(-)-N accumulation and NO/N2O emission. Integrated analyses indicated that the coupling of simultaneous nitrification, anammox and denitrification processes (SNAD) were the primary reason accounted for the enhanced NH4(+)-N treatment performance. NH4(+)-N removal pathways can be ranked as follows: nitrification (amoA, archaeal) (54.6%)>partial denitrification (nirS, nirK) and anammox (37.8%)>anammox and partial denitrification (narG, napA) (12.6%). Specifically, NH4(+)-N removal was significantly inhibited by NO2(-)-N accumulation in the system (-21.6% inhibition). Results from stepwise regression analysis suggested that the NH4(+) removal rate was collectively controlled by amoA, archaeal, anammox, nirS, nirK, narG and napA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Effect of operating temperature on transient behaviour of a biofilter treating waste-air containing n-butanol vapour during intermittent loading.

    PubMed

    Feizi, Farzaneh; Nasernejad, Bahram; Zamir, Seyed Morteza

    2016-01-01

    Transient-state removal of n-butanol vapour was investigated in a biofilter (BF) packed with compost and lava rock at different operating temperatures in the range of 30-45°C under intermittent loading (8 h per day). Adsorption on the inactive bed and biodegradation in the microbial-active bed were studied separately at an empty bed residence time (EBRT) of 1 min and inlet concentrations of 2.6-3.2 g m(-3), respectively. According to the transient experiments, the highest removal efficiency (RE) around 86% was obtained at 40°C due to a high microbial activity. Comparison of CO2 production and pure adsorption of n-butanol showed that adsorption was the major mechanism in the start-up of BF at each operating condition; although the impact of adsorption declined as temperature increased from 30°C to 45°C. The process was reaction limited at all operating conditions. Based on the determination of stoichiometric coefficients of n-butanol biodegradation, the CO2 production level was significantly lower than that of the chemical oxidation process which resulted in a decrease in environmental pollution.

  1. RCN1-regulated phosphatase activity and EIN2 modulate hypocotyl gravitropism by a mechanism that does not require ethylene signaling.

    PubMed

    Muday, Gloria K; Brady, Shari R; Argueso, Cristiana; Deruère, Jean; Kieber, Joseph J; DeLong, Alison

    2006-08-01

    The roots curl in naphthylphthalamic acid1 (rcn1) mutant of Arabidopsis (Arabidopsis thaliana) has altered auxin transport, gravitropism, and ethylene response, providing an opportunity to analyze the interplay between ethylene and auxin in control of seedling growth. Roots of rcn1 seedlings were previously shown to have altered auxin transport, growth, and gravitropism, while rcn1 hypocotyl elongation exhibited enhanced ethylene response. We have characterized auxin transport and gravitropism phenotypes of rcn1 hypocotyls and have explored the roles of auxin and ethylene in controlling these phenotypes. As in roots, auxin transport is increased in etiolated rcn1 hypocotyls. Hypocotyl gravity response is accelerated, although overall elongation is reduced, in etiolated rcn1 hypocotyls. Etiolated, but not light grown, rcn1 seedlings also overproduce ethylene, and mutations conferring ethylene insensitivity restore normal hypocotyl elongation to rcn1. Auxin transport is unaffected by treatment with the ethylene precursor 1-aminocyclopropane carboxylic acid in etiolated hypocotyls of wild-type and rcn1 seedlings. Surprisingly, the ethylene insensitive2-1 (ein2-1) and ein2-5 mutations dramatically reduce gravitropic bending in hypocotyls. However, the ethylene resistant1-3 (etr1-3) mutation does not significantly affect hypocotyl gravity response. Furthermore, neither the etr1 nor the ein2 mutation abrogates the accelerated gravitropism observed in rcn1 hypocotyls, indicating that both wild-type gravity response and enhanced gravity response in rcn1 do not require an intact ethylene-signaling pathway. We therefore conclude that the RCN1 protein affects overall hypocotyl elongation via negative regulation of ethylene synthesis in etiolated seedlings, and that RCN1 and EIN2 modulate hypocotyl gravitropism and ethylene responses through independent pathways.

  2. Activation of HLS1 by Mechanical Stress via Ethylene-Stabilized EIN3 Is Crucial for Seedling Soil Emergence

    PubMed Central

    Shen, Xing; Li, Yanli; Pan, Ying; Zhong, Shangwei

    2016-01-01

    The seeds of terrestrial flowering plants often start their life cycle in subterranean darkness. To protect the fragile apical meristematic tissues and cotyledons from mechanical injuries during soil penetration, dicotyledonous seedlings form an elegant apical hook at the top of the hypocotyl. The apical hook has been considered as an adaption structure to the subterranean environment. However, the role of the apical hook in seedling emergence and the molecular mechanism of apical hook formation under real-life conditions remain highly speculative. Here, we find that HOOKLESS 1 (HLS1), a critical gene in apical hook formation in Arabidopsis thaliana, is required for seedling emergence from the soil. When grown under soil, hls1 mutant exhibits severe emergence defects. By contrast, HLS1 overexpression in the hls1 background fully restores emergence defects and displays better emergence capacity than that of WT. Our results indicate that HLS1 transcription is stimulated in response to the mechanical stress of soil cover, which is dependent on the function of the transcription factors ETHYLENE INSENSITIVE 3 (EIN3) and EIN3-LIKE 1 (EIL1). Soil-conferred mechanical stress activates the ethylene signaling pathway to stabilize EIN3 by repressing the activity of the F-box proteins EBF1 and EBF2. These combined results reveal a signaling pathway in which plant seedlings transduce the mechanical pressure of soil cover to correctly modulate apical hook formation during soil emergence. PMID:27822221

  3. Activation of HLS1 by Mechanical Stress via Ethylene-Stabilized EIN3 Is Crucial for Seedling Soil Emergence.

    PubMed

    Shen, Xing; Li, Yanli; Pan, Ying; Zhong, Shangwei

    2016-01-01

    The seeds of terrestrial flowering plants often start their life cycle in subterranean darkness. To protect the fragile apical meristematic tissues and cotyledons from mechanical injuries during soil penetration, dicotyledonous seedlings form an elegant apical hook at the top of the hypocotyl. The apical hook has been considered as an adaption structure to the subterranean environment. However, the role of the apical hook in seedling emergence and the molecular mechanism of apical hook formation under real-life conditions remain highly speculative. Here, we find that HOOKLESS 1 (HLS1), a critical gene in apical hook formation in Arabidopsis thaliana, is required for seedling emergence from the soil. When grown under soil, hls1 mutant exhibits severe emergence defects. By contrast, HLS1 overexpression in the hls1 background fully restores emergence defects and displays better emergence capacity than that of WT. Our results indicate that HLS1 transcription is stimulated in response to the mechanical stress of soil cover, which is dependent on the function of the transcription factors ETHYLENE INSENSITIVE 3 (EIN3) and EIN3-LIKE 1 (EIL1). Soil-conferred mechanical stress activates the ethylene signaling pathway to stabilize EIN3 by repressing the activity of the F-box proteins EBF1 and EBF2. These combined results reveal a signaling pathway in which plant seedlings transduce the mechanical pressure of soil cover to correctly modulate apical hook formation during soil emergence.

  4. Verbesserte Ausbildung für neue Betriebsleiter und -ingenieure - eine wichtige Investition in die Zukunft

    NASA Astrophysics Data System (ADS)

    Franta, Oliver

    Bedingt durch die Globalisierung und die damit einhergehende Verschärfung des Wettbewerbs befinden sich die Produktionsbetriebe der chemischen Industrie in stetigem Wandel. Für Betriebsleiter und Betriebsingenieure werden damit Fähigkeiten wie Kostenmanagement, Sozial- und Organisationskompetenz, Führungsqualifikationen und unternehmerisches Handeln immer wichtiger. Neben den Anforderungsprofilen bei Neueinstellungen ist dies auch bei der Fortbildung zu berücksichtigen. Das Trainingsprogramm der Evonik Degussa wurde daher durch die Konzeption neuer Seminare und die Anpassung bestehender Weiterbildungsmaßnahmen weiterentwickelt. Neben Vorträgen und Fallbeispielen sind ebenfalls die Durchführung von Planspielen sowie das Kennenlernen eines Produktionsbetriebes einer anderen Organisationseinheit enthalten. Ziel ist es vor allem die unternehmerische Orientierung neuer Betriebsleiter und -ingenieure zu fördern, die Innovationsgeschwindigkeit zu erhöhen und durch Kenntnis und Nutzung bereits anderweitig entwickelter Lösungen und Methoden die Produktivität zu steigern. Die Produktionsmeister werden aufgrund der Bedeutung dieser Funktion für die Führung der Mitarbeiter und bei der Umsetzung von Veränderungsprojekten in das Ausbildungsprogramm einbezogen. Der Erfolg des Trainingsprogramms zeigt sich an den Teilnehmerzahlen und den ausgesprochen positiven Rückmeldungen.

  5. Schönheit und andere Provokationen - Eine neue evolutionsbiologische Theorie der Kunst

    NASA Astrophysics Data System (ADS)

    Junker, Thomas

    Die Evolution hat viele spektakuläre Phänomene hervorgebracht - von der Eleganz des Vogelflugs über die gigantischen Körper der Dinosaurier und die farbenprächtige Vielfalt der Korallenriffe bis hin zu ihrem jüngsten Geniestreich - der menschlichen Kunst. Die schönen Künste - Malerei, Bildhauerei und Architektur, Theater, Tanz, Oper und Filmkunst, Musik und Literatur - Produkte der Evolution? Diese Vorstellung mutet vielen Menschen fremd an, aber wie könnte es anders sein? Denn wenn Charles Darwin recht hat, dann sind nicht nur die körperlichen Merkmale der Menschen als Antworten auf die Erfordernisse des Lebens entstanden, sondern auch ihre geistigen Fähigkeiten und Verhaltensweisen. Im Jahr 1859 hatte er auf den letzten Seiten seines berühmten Buches über die Entstehung der Arten eine kühne Prophezeiung gemacht: Durch die Evolutionstheorie werde es "zu einer bemerkenswerten Revolution in der Naturwissenschaft kommen […]. Die Psychologie wird auf die neue Grundlage gestellt, dass jede geistige Kraft und Fähigkeit notwendigerweise durch graduelle Übergänge erworben wird“ (Darwin 1859, S. 484, 488; Junker 2008).

  6. Structure of the NPr:EIN(Ntr) Complex: Mechanism for Specificity in Paralogous Phosphotransferase Systems.

    PubMed

    Strickland, Madeleine; Stanley, Ann Marie; Wang, Guangshun; Botos, Istvan; Schwieters, Charles D; Buchanan, Susan K; Peterkofsky, Alan; Tjandra, Nico

    2016-12-06

    Paralogous enzymes arise from gene duplication events that confer a novel function, although it is unclear how cross-reaction between the original and duplicate protein interaction network is minimized. We investigated HPr:EI(sugar) and NPr:EI(Ntr), the initial complexes of paralogous phosphorylation cascades involved in sugar import and nitrogen regulation in bacteria, respectively. Although the HPr:EI(sugar) interaction has been well characterized, involving multiple complexes and transient interactions, the exact nature of the NPr:EI(Ntr) complex was unknown. We set out to identify the key features of the interaction by performing binding assays and elucidating the structure of NPr in complex with the phosphorylation domain of EI(Ntr) (EIN(Ntr)), using a hybrid approach involving X-ray, homology, and sparse nuclear magnetic resonance. We found that the overall fold and active-site structure of the two complexes are conserved in order to maintain productive phosphorylation, however, the interface surface potential differs between the two complexes, which prevents cross-reaction.

  7. Nahal Ein Gev II, a Late Natufian Community at the Sea of Galilee

    PubMed Central

    Grosman, Leore; Munro, Natalie D.; Abadi, Itay; Boaretto, Elisabetta; Shaham, Dana; Belfer-Cohen, Anna; Bar-Yosef, Ofer

    2016-01-01

    The Natufian culture is of great importance as a starting point to investigate the dynamics of the transition to agriculture. Given its chronological position at the threshold of the Neolithic (ca. 12,000 years ago) and its geographic setting in the productive Jordan Valley, the site of Nahal Ein Gev II (NEG II) reveals aspects of the Late Natufian adaptations and its implications for the transition to agriculture. The size of the site, the thick archaeological deposits, invested architecture and multiple occupation sub-phases reveal a large, sedentary community at least on par with Early Natufian camps in the Mediterranean zone. Although the NEG II lithic tool kit completely lacks attributes typical of succeeding Pre Pottery Neolithic A (PPNA) assemblages, the artistic style is more closely related to the early PPNA world, despite clear roots in Early Natufian tradition. The site does not conform to current perceptions of the Late Natufians as a largely mobile population coping with reduced resource productivity caused by the Younger Dryas. Instead, the faunal and architectural data suggest that the sedentary populations of the Early Natufian did not revert back to a nomadic way of life in the Late Natufian in the Jordan Valley. NEG II encapsulates cultural characteristics typical of both Natufian and PPNA traditions and thus bridges the crossroads between Late Paleolithic foragers and Neolithic farmers. PMID:26815363

  8. Ein Entscheidungsmodell zur Weitergabe persönlicher Daten im Internet

    NASA Astrophysics Data System (ADS)

    Treiblmaier, Horst

    In den vergangenen zwei Jahrzehnten wandelte sich das Internet von einer Spielwiese für technikbegeisterte Computerspezialisten zu einem vielseitig einsetzbaren weltweiten Netzwerk für Privatpersonen und Unternehmen. Maßgeblichen Anteil daran besaß die rasante Entwicklung des World Wide Web (WWW), das, durch die Möglichkeit multimediale Inhalte zu vermitteln, für einen großen Teil der Bevölkerung industrialisierter Länder zu einem wesentlichen Bestandteil des täglichen Lebens wurde. Dass diese Entwicklung noch lange nicht abgeschlossen ist, zeigt die derzeitige Diskussion zum Thema Web 2.0 bzw. 3.0. Waren es in den letzten Jahren die hohen Umsatzzuwächse im E-Commerce und multimedial gestaltete Webseiten in Kombination mit aufwändigen Applikationen, die für ständig steigende Nutzerzahlen im World Wide Web sorgten, so wird dieser Innovationsschub nunmehr durch eine Vielzahl von Anwendungen fortgesetzt, die sich durch die zunehmende Vernetzung der Nutzer untereinander auszeichnen.

  9. Comparative assessment of a biofilter, a biotrickling filter and a hollow fiber membrane bioreactor for odor treatment in wastewater treatment plants.

    PubMed

    Lebrero, Raquel; Gondim, Ana Celina; Pérez, Rebeca; García-Encina, Pedro A; Muñoz, Raúl

    2014-02-01

    A low abatement efficiency for the hydrophobic fraction of odorous emissions and a high footprint are often pointed out as the major drawbacks of conventional biotechnologies for odor treatment. In this work, two conventional biotechnologies (a compost-based biofilter, BF, and a biotrickling filter, BTF), and a hollow-fiber membrane bioreactor (HF-MBR) were comparatively evaluated in terms of odor abatement potential and pressure drop (ΔP) at empty bed residence times (EBRTs) ranging from 4 to 84 s, during the treatment of methyl-mercaptan, toluene, alpha-pinene and hexane at trace level concentrations (0.75-4.9 mg m(-3)). High removal efficiencies (RE > 90% regardless of the air pollutant) were recorded in the BF at EBRTs ≥ 8 s, although the high ΔP across the packed bed limited its cost-effective operation to EBRTs > 19 s. A complete methyl-mercaptan, toluene and alpha-pinene removal was recorded in the BTF at EBRTs ≥ 4 s and ΔP lower than 33 mmH2O (∼611 Pa mbed(-1)), whereas slightly lower REs were observed for hexane (∼88%). The HF-MBR completely removed methyl-mercaptan and toluene at all EBRTs tested, but exhibited an unstable alpha-pinene removal performance as a result of biomass accumulation and a low hexane abatement efficiency. Thus, a periodical membrane-cleaning procedure was required to ensure a steady abatement performance. Finally, a high bacterial diversity was observed in the three bioreactors in spite of the low carbon source spectrum present in the air emission. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Efficiency of a locally designed pilot-scale trickling biofilter (TBF) system in natural environment for the treatment of domestic wastewater.

    PubMed

    Rasool, Tabassum; Rehman, Abdul; Naz, Iffat; Ullah, Rahat; Ahmed, Safia

    2017-06-07

    In the present study, a cost-effective and simple stone media pilot-scale trickling biofilter (TBF) was designed, constructed and operated in a continuous recirculation mode for wastewater treatment with a hydraulic flow rate of 1.2 L/min (Q = 0.072 m(3)/h) and hydraulic loading (Q/A) of 0.147 m(3)/day for 15 weeks at a temperature range of 14.5-36°C. A substantial reduction in the average concentration of different pollution indicators, such as chemical oxygen demand (COD) (85.6%), biochemical oxygen demand (BOD5) (85.6%), total dissolved solid (TDS) (62.8%), total suspended solid (TSS) (99.9%), electrical conductivity (EC) (15.1%), phosphates (63.22%), sulfates (28.5%) and total nitrogen (TN) (34.4%), was observed during 15 weeks of operational period. Whereas a considerable average increase in the levels of dissolved oxygen (DO) (63.2%) was found after treatment of wastewater by the TBF system. No significant reduction in most probable number (MPN) index of fecal coliforms was observed in the effluent in first 9 weeks of operation. However, a significant reduction in the MPN of fecal coliforms was observed, i.e. 80-90% in the last few weeks of treatment. Thus, overall results suggest that pilot-scale TBF has a great potential to be transferred to field scale for treating sewage for small communities in developing countries, in order to produce effluent of good quality, which can be safely used for irrigation as well as ornamental purposes.

  11. Tertiary nitrogen removal for municipal wastewater using a solid-phase denitrifying biofilter with polycaprolactone as the carbon source and filtration medium.

    PubMed

    Li, Peng; Zuo, Jiane; Wang, Yajiao; Zhao, Jian; Tang, Lei; Li, Zaixing

    2016-04-15

    Tertiary nitrogen removal technologies are needed to reduce the excess nitrogen that is discharged into sensitive aquatic ecosystems. An integrated solid-phase denitrification biofilter (SDNF) was developed with dual media to remove nitrate and suspended solids (SS) from the secondary effluent of municipal wastewater treatment plants. Biodegradable polymer pellets of polycaprolactone (PCL) served as the biofiltration medium and carbon source for denitrification. Long-term continuous operation of the SDNF was conducted with real secondary effluent to evaluate the denitrification performance and effects of influent nitrate loading rates (NLR) and operating temperatures. The results indicated that both nitrate and SS were effectively removed. The SDNF had a strong tolerance for fluctuations in influent NLR, and a maximum denitrification rate of 3.80 g N/(L·d) was achieved. The low temperature had a significant impact on nitrogen removal, yet the denitrification rate was still maintained at a relative high level to as much as 1.23 g N/(L·d) even at approximately 8.0 °C in winter. Nitrite accumulation and excessive organics residue in the effluent were avoided throughout the whole experiment, except on occasional days in the lag phase. The observed biomass yield was calculated to be 0.44 kgVSS/kgPCL. The microbial diversity and community structure of the biofilm in the SDNF were revealed by Illumina high-throughput sequencing. The special carbon source led to an obvious succession of microbial community from the initial inoculum (activated sludge from aerobic tanks), and included a decrease in microbial diversity and a shift in the dominant groups, which were identified to be members of the family Comamonadaceae in the SDNF. The SDNF developed in this study was verified to be an efficient technology for tertiary nitrogen removal from secondary effluent. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Olivibacter oleidegradans sp. nov., a hydrocarbon-degrading bacterium isolated from a biofilter clean-up facility on a hydrocarbon-contaminated site.

    PubMed

    Szabó, István; Szoboszlay, Sándor; Kriszt, Balázs; Háhn, Judit; Harkai, Péter; Baka, Erzsébet; Táncsics, András; Kaszab, Edit; Privler, Zoltán; Kukolya, József

    2011-12-01

    A novel hydrocarbon-degrading, Gram-negative, obligately aerobic, non-motile, non-sporulating, rod-shaped bacterium, designated strain TBF2/20.2(T), was isolated from a biofilter clean-up facility set up on a hydrocarbon-contaminated site in Hungary. It was characterized by using a polyphasic approach to determine its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate is affiliated with the genus Olivibacter in the family Sphingobacteriaceae. It was found to be related most closely to Olivibacter ginsengisoli Gsoil 060(T) (93.3% 16S rRNA gene sequence similarity). Strain TBF2/20.2(T) grew at pH 6-9 (optimally at pH 6.5-7.0) and at 15-42 °C (optimally at 30-37 °C). The major fatty acids were iso-C(15:0) (39.4%), summed feature 3 (iso-C(15:0) 2-OH and/or C(16:1)ω7c; 26.0%), iso-C(17:0) 3-OH (14.5%) and C(16:0) (4.5%). The major menaquinone was MK-7 and the predominant polar lipid was phosphatidylethanolamine. The DNA G+C content of strain TBF2/20.2(T) was 41.2 mol%. Physiological and chemotaxonomic data further confirmed the distinctiveness of strain TBF2/20.2(T) from recognized members of the genus Olivibacter. Thus, strain TBF2/20.2(T) is considered to represent a novel species of the genus Olivibacter, for which the name Olivibacter oleidegradans sp. nov. is proposed. The type strain is TBF2/20.2(T) (=NCAIM B 02393(T) =CCM 7765(T)).

  13. Ansätze für eine Bifurkationsanalyse von RF LC-Tank VCOs unter Berücksichtigung nichtlinearer Bauelementegleichungen

    NASA Astrophysics Data System (ADS)

    Zorn, C.; Bremer, J.-K.; Mathis, W.

    2008-05-01

    Es wird ein alternativer Ansatz zum Entwurf von vollintegrierten LC Oszillatoren mit Hilfe der Andronov-Hopf Bifurkationsanalyse unter Einbeziehung eines nichtlinearen Overall-Modells für MOS-Transistoren (EKV-Modell) vorgestellt. Das in dieser Arbeit vorgestellte Verfahren beschreibt die MOS-Kapazität des VCOs über geometrische Gundgrößen, die damit nur als Längen- und Weitenverhältnisse in die Bifurkationsanalyse eingehen. Zur Beschreibung der MOS-Kapazität wurde ein Basic-Charge-Modell, wie es in den Arbeiten von Enz und Vittoz vorgestellt wurde, in Verbindung einer expliziten analytischen Näherung des Oberflächenpotenzials verwendet. Das Verfahren ermöglicht es, als zusätzlichen Freiheitsgrad für den Designer auch die Amplitude zur Optimierung der Bauteilparameter heranzuziehen und vorab eine genauere Abschätzung der Parameter des Varaktors zu erhalten. Zusammengefasst in einer Toolbox führt die Anwendung des Verfahrens auf einen grafischen Optimierungsprozess, mit dessen Hilfe die Parameter analytisch bestimmt werden können. Die verwendete Methode erweitert den von Hajimiri und Ham vorgestellten Entwurfsprozess von LC-Tank VCOs um eine Stabilitätsanalyse, die Berücksichtigung harmonischer höherer Ordnung und die physikalisch exakte Modellierung der Varaktorkapazitäten.

  14. [Homöopathisch-phytotherapeutische Behandlung des Reizdarmsyndroms mit Magen-Darm-Entoxin N®: Eine Anwendungsbeobachtung].

    PubMed

    Märtens, Diane; Range, Natasha; Günnewich, Nils; Gruber, Nicola; Schmidt, Stefan

    2017-01-01

    Hintergrund: In dieser Anwendungsbeobachtung wird zum ersten Mal die Behandlung des Reizdarmsyndroms (RDS) mit einem homöopathisch-phytotherapeutischen Komplexpräparat beschrieben. Methodik: Ziel der 6-wöchigen Therapie mit dem Magen-Darm-Entoxin N® war die Reduzierung der RDS-Symptomatik sowie die Verbesserung der Lebensqualität. Zielkriterien waren die Veränderungen in der Irritable Bowel Syndrome - Severity Scoring System (IBS-SSS) und der Irritable Bowel Syndrome - Quality-of-Life Scale (IBS-QoL). Die Patient/innen (N = 41; Alter 44,0 ± 15,74 Jahre) wurden zu gleichen Teilen in einer Hausarztpraxis (N = 20) und einer Heilpraktikerpraxis (N = 21) rekrutiert. Ergebnisse: Der IBS-QoL-Score verringerte sich signifikant (prä: 35,9 ± 16,3; post: 20,1 ± 13,4; t = 8,504; p < 0,001). Die Effektstärke betrug 1,34 (Cohens d). Der IBS-SSS-Score verringerte sich ebenfalls signifikant (prä: 239,4 ± 83,4; post: 123,7 ± 80,9; t = 7,825; p < 0,001) mit einer Effektstärke von d = 1,24. Die Neben- und Wechselwirkungen waren minimal und signifikante Unterschiede zwischen beiden Praxen wurden nicht gefunden. Schlussfolgerungen: Magen-Darm-Entoxin N® ist eine sichere und sinnvolle Therapieoption bei der Behandlung des RDS. Allerdings sollten randomisierte kontrollierte Studien folgen, um die Spezifizität der Ergebnisse dieser Anwendungsbeobachtung zu stützen. © 2017 S. Karger GmbH, Freiburg.

  15. Vernachlässigte klinische Merkmale der follikulotropen Mycosis fungoides: eine große klinische Fallserie.

    PubMed

    Baykal, Can; Atci, Tugba; Ozturk Sari, Sule; Polat Ekinci, Algun; Buyukbabani, Nesimi

    2017-03-01

    Als seltene Form der Mycosis fungoides (MF), ist die follikulotrope MF (FMF) durch ein breites Spektrum klinischer Symptome gekennzeichnet. Dazu gehören, neben den vorherrschenden follikulären Läsionen, auch viele atypische Manifestationen. Das Ziel der vorliegenden Studie war eine klinische Bewertung von FMF-Patienten, unter besonderer Berücksichtigung von vernachlässigten dermatologischen Merkmalen. Insgesamt wurden 27 FMF-Patienten aus dem 572 Patienten umfassenden MF-Register unserer Abteilung retrospektiv bezüglich ihrer Demographie sowie der klinischen Merkmale, Behandlungsformen, Nachsorge und Therapieergebnisse bewertet. Neben den bekannten klinischen Symptomen der FMF fanden wir Lichen-spinulosus-artige Läsionen mit begleitender Hypopigmentierung (n = 3) und Alopezie (n = 2), infiltrierte/erhabene, erythematöse Plaques im Gesicht, die zunächst als Lupus tumidus angesehen wurden (n = 2), pseudotumorale Läsionen, die klinisch eine MF im Tumorstadium vortäuschten (n = 1), dauerhafte Exkoriationen (n = 1), erythematöse, Rosazea-artige Papeln im Gesicht (n = 1) sowie kuppelförmige, asymptomatische, mit Muzin gefüllte (in der Histologie) Papeln/Knoten (n = 2), die andere krankheitsbedingte Läsionen überlagerten. Es kamen mehrere Therapieansätze mit unterschiedlichem Ergebnis zur Anwendung. Acht (29,6 %) Patienten hatten FMF im Spätstadium. Das Bewusstsein für vernachlässigte klinische Symptome kann wesentlich dazu beitragen, verspätete Diagnosen dieser aggressiven MF-Variante zu verringern. © 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  16. Unterstützung der IT-Service-Management-Prozesse an der Technischen Universität München durch eine Configuration-Management-Database

    NASA Astrophysics Data System (ADS)

    Knittl, Silvia

    Hochschulprozesse in Lehre und Verwaltung erfordern durch die steigende Integration und IT-Unterstützung ein sogenanntes Business Alignment der IT und damit auch ein professionelleres IT-Service-Management (ITSM). Die IT Infrastructure Library (ITIL) mit ihrer Beschreibung von in der Praxis bewährten Prozessen hat sich zum de-facto Standard im ITSM etabliert. Ein solcher Prozess ist das Konfigurationsmanagement. Es bildet die IT-Infrastruktur als Konfigurationselemente und deren Beziehungen in einem Werkzeug, genannt Configuration Management Database (CMDB), ab und unterstützt so das ITSM. Dieser Bericht beschreibt die Erfahrungen mit der prototypischen Einführung einer CMDB an der Technischen Universität München.

  17. Nitric Oxide Has a Concentration-Dependent Effect on the Cell Cycle Acting via EIN2 in Arabidopsis thaliana Cultured Cells

    PubMed Central

    Novikova, Galina V.; Mur, Luis A. J.; Nosov, Alexander V.; Fomenkov, Artem A.; Mironov, Kirill S.; Mamaeva, Anna S.; Shilov, Evgeny S.; Rakitin, Victor Y.; Hall, Michael A.

    2017-01-01

    Ethylene is known to influence the cell cycle (CC) via poorly characterized roles whilst nitric oxide (NO) has well-established roles in the animal CC but analogous role(s) have not been reported for plants. As NO and ethylene signaling events often interact we examined their role in CC in cultured cells derived from Arabidopsis thaliana wild-type (Col-0) plants and from ethylene-insensitive mutant ein2-1 plants. Both NO and ethylene were produced mainly during the first 5 days of the sub-cultivation period corresponding to the period of active cell division. However, in ein2-1 cells, ethylene generation was significantly reduced while NO levels were increased. With application of a range of concentrations of the NO donor, sodium nitroprusside (SNP) (between 20 and 500 μM) ethylene production was significantly diminished in Col-0 but unchanged in ein2-1 cells. Flow cytometry assays showed that in Col-0 cells treatments with 5 and 10 μM SNP concentrations led to an increase in S-phase cell number indicating the stimulation of G1/S transition. However, at ≥20 μM SNP CC progression was restrained at G1/S transition. In the mutant ein2-1 strain, the index of S-phase cells was not altered at 5–10 μM SNP but decreased dramatically at higher SNP concentrations. Concomitantly, 5 μM SNP induced transcription of genes encoding CDKA;1 and CYCD3;1 in Col-0 cells whereas transcription of CDKs and CYCs were not significantly altered in ein2-1 cells at any SNP concentrations examined. Hence, it is appears that EIN2 is required for full responses at each SNP concentration. In ein2-1 cells, greater amounts of NO, reactive oxygen species, and the tyrosine-nitrating peroxynitrite radical were detected, possibly indicating NO-dependent post-translational protein modifications which could stop CC. Thus, we suggest that in Arabidopsis cultured cells NO affects CC progression as a concentration-dependent modulator with a dependency on EIN2 for both ethylene production and a NO

  18. Nitric Oxide Has a Concentration-Dependent Effect on the Cell Cycle Acting via EIN2 in Arabidopsis thaliana Cultured Cells.

    PubMed

    Novikova, Galina V; Mur, Luis A J; Nosov, Alexander V; Fomenkov, Artem A; Mironov, Kirill S; Mamaeva, Anna S; Shilov, Evgeny S; Rakitin, Victor Y; Hall, Michael A

    2017-01-01

    Ethylene is known to influence the cell cycle (CC) via poorly characterized roles whilst nitric oxide (NO) has well-established roles in the animal CC but analogous role(s) have not been reported for plants. As NO and ethylene signaling events often interact we examined their role in CC in cultured cells derived from Arabidopsis thaliana wild-type (Col-0) plants and from ethylene-insensitive mutant ein2-1 plants. Both NO and ethylene were produced mainly during the first 5 days of the sub-cultivation period corresponding to the period of active cell division. However, in ein2-1 cells, ethylene generation was significantly reduced while NO levels were increased. With application of a range of concentrations of the NO donor, sodium nitroprusside (SNP) (between 20 and 500 μM) ethylene production was significantly diminished in Col-0 but unchanged in ein2-1 cells. Flow cytometry assays showed that in Col-0 cells treatments with 5 and 10 μM SNP concentrations led to an increase in S-phase cell number indicating the stimulation of G1/S transition. However, at ≥20 μM SNP CC progression was restrained at G1/S transition. In the mutant ein2-1 strain, the index of S-phase cells was not altered at 5-10 μM SNP but decreased dramatically at higher SNP concentrations. Concomitantly, 5 μM SNP induced transcription of genes encoding CDKA;1 and CYCD3;1 in Col-0 cells whereas transcription of CDKs and CYCs were not significantly altered in ein2-1 cells at any SNP concentrations examined. Hence, it is appears that EIN2 is required for full responses at each SNP concentration. In ein2-1 cells, greater amounts of NO, reactive oxygen species, and the tyrosine-nitrating peroxynitrite radical were detected, possibly indicating NO-dependent post-translational protein modifications which could stop CC. Thus, we suggest that in Arabidopsis cultured cells NO affects CC progression as a concentration-dependent modulator with a dependency on EIN2 for both ethylene production and a NO

  19. Kopplung eines auf der Momentenmethode basierenden Computerprogramms mit einem FEM-Algorithmus zur Berechnung von elektromagnetischen Streuproblemen im medizinischen Bereich

    NASA Astrophysics Data System (ADS)

    Schick, M.; Landstorfer, F. M.

    2004-05-01

    Am Beispiel der Verkopplung von medizinischen Geräten über den menschlichen Körper werden elektromagnetische Störphänomene im Klinikbereich betrachtet. Für die Berechnung dieser komplexen Szenarien wird zum einen die Momentenmethode (MoM) verwendet, die sich in besonderem Maße für die Berücksichtigung metallischer Strukturen und offener Streuprobleme eignet, und zum anderen die Methode der Finiten Elemente (FEM), mit der die Eigenschaften des menschlichen Körpers besser berücksichtigt werden können. Mit Hilfe des Äquivalenzprinzips lässt sich das Gesamtproblem in zwei Teile zerlegen, in ein inneres und in ein äußeres. Der Außenraum wird dabei mit der MoM behandelt und das Innere, d.h. der Körper mit der FEM. Die Kopplung der beiden Methoden erfolgt an der Körperoberfläche über äquivalente Oberflächenströme. Durch Lösen des resultierenden linearen Gleichungssystems für das gesamte Problem lassen sich dann die Oberflächenströme und die über die Kontinuitätsgleichung miteinander verknüpften elektromagnetischen Felder bestimmen.

  20. Introduction of a Diagnosis Related Groups’ Case Flat Rate System: Hopes and Fears (einfuerhrng eines drg-fallpauschalensystems - hoffnungen und aengste)

    DTIC Science & Technology

    2000-06-01

    GOnter Neubauer Universittt der Bundeswehr M(Jnchen Neuordnung der KrankenhausvergUtung 15 Gerhard Knorr Bayerisches Staatsministerium fOr Arbeit und...Erlbse zu stellen. Nur eine solche trans- parente Vorgehensweise wird auch der entsprechenden Sachlage gerecht. -10- Schr ~itt zu e1 in U411 duc...user gelten. Unterschiede in der Entgelthohe sind dabei nur sehr be- schr ~nkt m5glich: Zum einen, soweit es sich um Finanzierungstatbesttn- de handelt

  1. Effect of hypergravity on lignin formation and expression of lignin-related genes in inflorescence stems of an ethylene-insensitive Arabidopsis mutant ein3-1

    NASA Astrophysics Data System (ADS)

    Karahara, Ichirou; Kobayashi, Mai; Tamaoki, Daisuke; Kamisaka, Seiichiro

    Our previous studies have shown that hypergravity inhibits growth and promotes lignin forma-tion in inflorescence stems of Arabidopsis thaliana by up-regulation of genes involved in lignin biosynthesis (Tamaoki et al. 2006, 2009). In the present study, we have examined whether ethylene is involved in these responses using an ethylene-insensitive Arabidopsis mutant ein3-1. Our results revealed that hypergravity treatment at 300 G for 24 h significantly inhibited growth of inflorescence stems, promoted both deposition of acetyl bromide extractable lignin and gene expression involved in lignin formation in inflorescence stems of wild type plants. Growth inhibition of inflorescence stems was also observed in ein3-1. However, the effects of hypergravity on the promotion of the deposition of acetyl bromide lignin and the expression of genes involved in lignin formation were not observed in ein3-1, indicating that ethylene sig-naling is involved in the up-regulation of the expression of lignin-related genes as well as the promotion of deposition of lignin by hypergravity in Arabidopsis inflorescence stems.

  2. Members of the tomato LeEIL (EIN3-like) gene family are functionally redundant and regulate ethylene responses throughout plant development.

    PubMed

    Tieman, D M; Ciardi, J A; Taylor, M G; Klee, H J

    2001-04-01

    The plant hormone ethylene regulates many aspects of growth, development and responses to the environment. The Arabidopsis ETHYLENE INSENSITIVE3 (EIN3) protein is a nuclear-localized component of the ethylene signal-transduction pathway with DNA-binding activity. Loss-of-function mutations in this protein result in ethylene insensitivity in Arabidopsis. To gain a better understanding of the ethylene signal-transduction pathway in tomato, we have identified three homologs of the Arabidopsis EIN3 gene (LeEILs). Each of these genes complemented the ein3-1 mutation in transgenic Arabidopsis, indicating that all are involved in ethylene signal transduction. Transgenic tomato plants with reduced expression of a single LeEIL gene did not exhibit significant changes in ethylene response; reduced expression of multiple tomato LeEIL genes was necessary to reduce ethylene sensitivity significantly. Reduced LeEIL expression affected all ethylene responses examined, including leaf epinasty, flower abscission, flower senescence and fruit ripening. Our results indicate that the LeEILs are functionally redundant and positive regulators of multiple ethylene responses throughout plant development.

  3. Isolation and identification of highly pathogenic avian influenza virus subtype H5N1 from emus from the Ein Gedi oasis by the Dead Sea.

    PubMed

    Amnon, Inbar; Shkoda, Irina; Lapin, Ekaterina; Raibstein, Israel; Rosenbluth, Ezra; Nagar, Sagit; Perk, Shimon; Bellaiche, Michel; Davidson, Irit

    2011-09-01

    An avian influenza virus (AIV), A/Emu/Israel/552/2010/(H5N1), was isolated from a dead emu that was found in the Ein Gedi oasis near the Dead Sea. The virus molecular characterization was performed by reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time RT-PCR using AIV subtype-specific primers. The virus was of high pathogenicity, according to its intravenous pathogenicity index of 2.85 and the nucleotide sequencing at the cleavage site of the hemagglutinin gene, GERRRKKR, which is typical for highly pathogenic chicken influenza A viruses.

  4. Networking as a Seismograph for Social Development. A Contribution to the Function Expansion of Networks Using the Example of Health Promotion of the Socially Disadvantaged (Netzwerkbildung als Seismograph gesellschaftlicher Entwicklungen: Ein Beitrag zur Funktionserweiterung von Netzwerken am Beispiel der Gesundheitsfoerderung von sozial Benachteiligten)

    DTIC Science & Technology

    2008-03-01

    vollzieht sich in den letzten Jahren Ober eine Vielzahl von Netzwerken, uber die sich unterschiedlichste Akteure miteinander verknQ~pft haben. In...indirekt, politische 2 Akteure zu adressieren und bisherige Handlungsdefizite der Gesundheitsf6rderung bei sozial Benachteiligten auch uber neue...klassischen Sinne der Korporatismusanalyse impliziert, sondern gar eine Form der Einwandvorwegnahme darsteilt. Auf der Grundlage der durch die bislang uber

  5. Nitric oxide induces cotyledon senescence involving co-operation of the NES1/MAD1 and EIN2-associated ORE1 signalling pathways in Arabidopsis

    PubMed Central

    Du, Jing; Li, Manli; Kong, Dongdong; Wang, Lei; Lv, Qiang; Wang, Jinzheng; Bao, Fang; Gong, Qingqiu; Xia, Jinchan; He, Yikun

    2014-01-01

    After germination, cotyledons undertake the major role in supplying nutrients to the pre-photoautorophy angiosperm seedlings until they senesce. Like other senescence processes, cotyledon senescence is a programmed degenerative process. Nitric oxide can induce premature cotyledon senescence in Arabidopsis thaliana, yet the underlying mechanism remains elusive. A screen for genetic mutants identified the nes1 mutant, in which cotyledon senescence was accelerated by nitric oxide. Map-based cloning revealed that NES1 is allelic to a previously reported mitotic checkpoint family gene, MAD1. The nes1/mad1 mutants were restored to the wild type, in response to nitric oxide, by transforming them with pNES1::NES1. Ectopic expression of NES1 in the wild type delayed nitric oxide-mediated cotyledon senescence, confirming the repressive role of NES1. Moreover, two positive regulators of leaf senescence, the ethylene signalling component EIN2 and the transcription factor ORE1/AtNAC2/ANAC092, were found to function during nitric oxide-induced senescence in cotyledons. The block of ORE1 function delayed senescence and ectopic expression induced the process, revealing the positive role of ORE1. EIN2 was required to induce ORE1. Furthermore, the genetic interaction analysis between NES1 and ORE1 showed that the ore1 loss-of-function mutants were epistatic to nes1, suggesting the dominant role of ORE1 and the antagonistic role of NES1 during nitric oxide-induced cotyledon senescence in Arabidopsis. PMID:24336389

  6. Melker Meilensteine auf dem Weg in ein naturwissenschaftliches Zeitalter - Glanzlichter der Ausstellung zum Internationalen Astronomiejahr 2009 in der Melker Stiftsbibliothek.

    NASA Astrophysics Data System (ADS)

    Beck, Paul G.; Zotti, Georg

    2009-06-01

    Das Mittelalter wird weithin als die dunkle Epoche in der Geschichte der Europäischen Wissenschaften betrachtet, und insbesondere das Leben in den Klöstern galt lange Zeit als frei von jeglichem Interesse für Naturwissenschaften abseits der Medizin. Im Mittelalter galt die Astronomie bloß als Mittel zum Zweck, um religiöse und zivile Kalender erstellen zu können. Durch den Bestand der Handschriftenkammer der Melker Stiftsbibliothek eröffnet sich uns eine neue Sichtweise auf das gegen Ende des Mittelalters wachsende Interesse an den Naturwissenschaften. Dies wurde durch die starke Aufwertung der Klosterbibliothek im Rahmen der 'Melker Reform' im 15. Jahrhundert noch weiter verstärkt. Diese Epoche fällt mit der Frühphase der Universität Wien und der 'ersten Wiener Schule der Astronomie' zusammen. Dieser Artikel beleuchtet ausgewählte astronomischen Werke in der Melker Stiftsbibliothek zwischen dem frühen 9 und dem 18. Jahrhundert. Einen Schwerpunkt stellt das Wirken der Wiener Schule der Astronomie dar, wobei wir u.a. die Melker Abschrift von Peuerbachs Gutachten über den Kometen von 1456 sowie die im Stift Melk durchgeführte Beobachtung der Mondfinsternis von 1457 durch Regiomontanus und Peuerbach beleuchten. Dieser Beitrag ist der einführende Übersichtsartikel zum Ausstellungsprojekt in der Melker Stiftsbibliothek im Rahmen des Internationalen Jahres der Astronomie 2009. The medieval period is commonly seen as a dark epoch for science in Europe. Especially monasteries were seen as institutions without interest in natural sciences except for medicine. Astronomy was allegedly only a tool to construct religious and civil calendars. The inventory of the medieval manuscript collection of the library of the Abbey of Melk allows a new view on the growing interest in the exact sciences towards the end of the medieval ages. This interest was intensified through the increased importance of the monastery library due to the monastery reform

  7. A Unique Assemblage of Engraved Plaquettes from Ein Qashish South, Jezreel Valley, Israel: Figurative and Non-Figurative Symbols of Late Pleistocene Hunters-Gatherers in the Levant

    PubMed Central

    Yaroshevich, Alla; Bar-Yosef, Ofer; Boaretto, Elisabeta; Caracuta, Valentina; Greenbaum, Noam; Porat, Naomi; Roskin, Joel

    2016-01-01

    Three engraved limestone plaquettes from the recently excavated Epipaleolithic open-air site Ein Qashish South in the Jezreel Valley, Israel comprise unique evidence for symbolic behavior of Late Pleistocene foragers in the Levant. The engravings, uncovered in Kebaran and Geometric Kebaran deposits (ca. 23ka and ca. 16.5ka BP), include the image of a bird—the first figurative representation known so far from a pre-Natufian Epipaleolithic—along with geometric motifs such as chevrons, crosshatchings and ladders. Some of the engravings closely resemble roughly contemporary European finds interpreted as "systems of notations" or "artificial memory systems"–records related to timing of seasonal resources and associated aggregation events of nomadic groups. Moreover, similarly looking signs and patterns are well known from the context of the local Natufian—a final Epipaleolithic culture of sedentary or semi-sedentary foragers who started practicing agriculture. The investigation of the engravings found in Ein Qashish South involves conceptualizations developed in studies of European and local parallels, a selection of ethnographic examples and preliminary microscopic observations of the plaquettes. This shows that the figurative and non-figurative images comprise a coherent assemblage of symbols that might have been applied in order to store, share and transmit information related to social and subsistence realms of mobile bands. It further suggests that the site functioned as a locality of groups' aggregation and indicates social complexity of pre-Natufian foragers in the Levant. While alterations in social and subsistence strategies can explain the varying frequency of image use characterizing different areas of the Late Pleistocene world—the apparent similarity in graphics and the mode of their application support the possibility that symbol-mediated behavior has a common and much earlier origin. PMID:27557110

  8. A Unique Assemblage of Engraved Plaquettes from Ein Qashish South, Jezreel Valley, Israel: Figurative and Non-Figurative Symbols of Late Pleistocene Hunters-Gatherers in the Levant.

    PubMed

    Yaroshevich, Alla; Bar-Yosef, Ofer; Boaretto, Elisabeta; Caracuta, Valentina; Greenbaum, Noam; Porat, Naomi; Roskin, Joel

    2016-01-01

    Three engraved limestone plaquettes from the recently excavated Epipaleolithic open-air site Ein Qashish South in the Jezreel Valley, Israel comprise unique evidence for symbolic behavior of Late Pleistocene foragers in the Levant. The engravings, uncovered in Kebaran and Geometric Kebaran deposits (ca. 23ka and ca. 16.5ka BP), include the image of a bird-the first figurative representation known so far from a pre-Natufian Epipaleolithic-along with geometric motifs such as chevrons, crosshatchings and ladders. Some of the engravings closely resemble roughly contemporary European finds interpreted as "systems of notations" or "artificial memory systems"-records related to timing of seasonal resources and associated aggregation events of nomadic groups. Moreover, similarly looking signs and patterns are well known from the context of the local Natufian-a final Epipaleolithic culture of sedentary or semi-sedentary foragers who started practicing agriculture. The investigation of the engravings found in Ein Qashish South involves conceptualizations developed in studies of European and local parallels, a selection of ethnographic examples and preliminary microscopic observations of the plaquettes. This shows that the figurative and non-figurative images comprise a coherent assemblage of symbols that might have been applied in order to store, share and transmit information related to social and subsistence realms of mobile bands. It further suggests that the site functioned as a locality of groups' aggregation and indicates social complexity of pre-Natufian foragers in the Levant. While alterations in social and subsistence strategies can explain the varying frequency of image use characterizing different areas of the Late Pleistocene world-the apparent similarity in graphics and the mode of their application support the possibility that symbol-mediated behavior has a common and much earlier origin.

  9. Transcriptional regulation of three EIN3-like genes of carnation (Dianthus caryophyllus L. cv. Improved White Sim) during flower development and upon wounding, pollination, and ethylene exposure.

    PubMed

    Iordachescu, Mihaela; Verlinden, Sven

    2005-08-01

    Using a combination of approaches, three EIN3-like (EIL) genes DC-EIL1/2 (AY728191), DC-EIL3 (AY728192), and DC-EIL4 (AY728193) were isolated from carnation (Dianthus caryophyllus) petals. DC-EIL1/2 deduced amino acid sequence shares 98% identity with the previously cloned and characterized carnation DC-EIL1 (AF261654), 62% identity with DC-EIL3, and 60% identity with DC-EIL4. DC-EIL3 deduced amino acid sequence shares 100% identity with a previously cloned carnation gene fragment, Dc106 (CF259543), 61% identity with Dianthus caryophyllus DC-EIL1 (AF261654), and 59% identity with DC-EIL4. DC-EIL4 shared 60% identity with DC-EIL1 (AF261654). Expression analyses performed on vegetative and flower tissues (petals, ovaries, and styles) during growth and development and senescence (natural and ethylene-induced) indicated that the mRNA accumulation of the DC-EIL family of genes in carnation is regulated developmentally and by ethylene. DC-EIL3 mRNA showed significant accumulation upon ethylene exposure, during flower development, and upon pollination in petals and styles. Interestingly, decreasing levels of DC-EIL3 mRNA were found in wounded leaves and ovaries of senescing flowers whenever ethylene levels increased. Flowers treated with sucrose showed a 2 d delay in the accumulation of DC-EIL3 transcripts when compared with control flowers. These observations suggest an important role for DC-EIL3 during growth and development. Changes in DC-EIL1/2 and DC-EIL4 mRNA levels during flower development, and upon ethylene exposure and pollination were very similar. mRNA levels of the DC-EILs in styles of pollinated flowers showed a positive correlation with ethylene production after pollination. The cloning and characterization of the EIN3-like genes in the present study showed their transcriptional regulation not previously observed for EILs.

  10. Analysis of combinatorial loss-of-function mutants in the Arabidopsis ethylene receptors reveals that the ers1 etr1 double mutant has severe developmental defects that are EIN2 dependent.

    PubMed

    Hall, Anne E; Bleecker, Anthony B

    2003-09-01

    Ethylene responses in Arabidopsis are controlled by the ETR receptor family. The receptors function as negative regulators of downstream signal transduction components and fall into two distinct subfamilies based on sequence similarity. To clarify the levels of functional redundancy between receptor isoforms, combinatorial mutant lines were generated that included the newly isolated ers1-2 allele. Based on the etiolated seedling growth response, all mutant combinations tested exhibited some constitutive ethylene responsiveness but also remained responsive to exogenous ethylene, indicating that all five receptor isoforms can contribute to signaling and no one receptor subtype is essential. On the other hand, light-grown seedlings and adult ers1 etr1 double mutants exhibited severe phenotypes such as miniature rosette size, delayed flowering, and sterility, revealing a distinct role for subfamily I receptors in light-grown plants. Introduction of an ein2 loss-of-function mutation into the ers1 etr1 double mutant line resulted in plants that phenocopy ein2 single mutants, indicating that all phenotypes observed in the ers1 etr1 double mutant are EIN2 dependent.

  11. Analysis of Combinatorial Loss-of-Function Mutants in the Arabidopsis Ethylene Receptors Reveals That the ers1 etr1 Double Mutant Has Severe Developmental Defects That Are EIN2 Dependent

    PubMed Central

    Hall, Anne E.; Bleecker, Anthony B.

    2003-01-01

    Ethylene responses in Arabidopsis are controlled by the ETR receptor family. The receptors function as negative regulators of downstream signal transduction components and fall into two distinct subfamilies based on sequence similarity. To clarify the levels of functional redundancy between receptor isoforms, combinatorial mutant lines were generated that included the newly isolated ers1-2 allele. Based on the etiolated seedling growth response, all mutant combinations tested exhibited some constitutive ethylene responsiveness but also remained responsive to exogenous ethylene, indicating that all five receptor isoforms can contribute to signaling and no one receptor subtype is essential. On the other hand, light-grown seedlings and adult ers1 etr1 double mutants exhibited severe phenotypes such as miniature rosette size, delayed flowering, and sterility, revealing a distinct role for subfamily I receptors in light-grown plants. Introduction of an ein2 loss-of-function mutation into the ers1 etr1 double mutant line resulted in plants that phenocopy ein2 single mutants, indicating that all phenotypes observed in the ers1 etr1 double mutant are EIN2 dependent. PMID:12953109

  12. Herstellung eines federelastischen Spangutes geringer Dichte als Matrix für Schüttdämmstoffe, für plattenförmige Dämmstoffe und leichte Spanplatten

    NASA Astrophysics Data System (ADS)

    Tröger, Johannes; Groß, Lucia

    Klimaschutz und die ständig steigenden Energiekosten erfordern eine kontinuierliche Verbesserung der Dämmstoffe. Eine Alternative zur relativ kostenaufwändigen Wärmedämmung durch Platten bzw. Matten auf Basis von mineralischen Stoffen, ist der Einsatz von schütt-bzw. einblasbaren Dämmstoffpartikeln. Späne aus Holz und andere Dämmstoffe aus nachwachsenden Rohstoffen waren schon vor dem ersten Weltkrieg die gebräuchlichsten Dämmstoffe überhaupt. Seit etwa fünfzehn Jahren werden u.a. für den Holzhausbau im zunehmenden Maße auch Fräs-, Säge und Hobelspäne für Wärmedämmzwecke eingesetzt [1], [2], [3]. Hervorzuheben ist der ökologische Aspekt dieser Dämmstoffe durch die Bindung von CO2 und den sinkenden Heizenergiebedarf. Die bisherige Philosophie bei der Gewinnung von Dämmstoffspänen beruhte darauf, anfallendes Spangut stofflich weiter zu nutzen. Die Recyclingspäne sollten dabei sowohl die Setzungssicherheit als auch eine möglichst gute Wärmedämmung gewährleisten.

  13. Common carp (Cyprinus carpio) response to two pieces of music ("Eine Kleine Nachtmusik" and "Romanza") combined with light intensity, using recirculating water system.

    PubMed

    Papoutsoglou, Sofronios E; Karakatsouli, Nafsika; Papoutsoglou, Eustratios S; Vasilikos, Georgios

    2010-09-01

    The objective of this study was to further investigate the effects of music on fish physiology, bearing in mind available information regarding the involvement of endogenous and exogenous factors in fish farming. Therefore, Cyprinus carpio (50.5 +/- 0.36 g) were reared in a recirculating water system under 80 and 200 lux and subjected to no music at all (control, ambient noise only), 4 h of Mozart's "Eine Kleine Nachtmusik", or 4 h of anonymous "Romanza-Jeux Interdits" for 106 days. Both music treatments resulted in increased growth performance at both light intensities, with Romanza treatment at 200 lux resulting in better growth performance than Mozart treatment. Furthermore, feed efficiency for the Romanza groups was significantly better than for the control. Although no significant music effect was apparent for brain neurotransmitters, lower anterior intestine alkaline protease levels were detected for both music treatments. Taking into consideration the numerous advantages of recirculating water systems, it should be emphasised that fish response to music expresses the results of various physiological and biochemical processes, especially when fish notably respond differently when subjected to two different pieces of music.

  14. Identification of rice ethylene-response mutants and characterization of MHZ7/OsEIN2 in distinct ethylene response and yield trait regulation.

    PubMed

    Ma, Biao; He, Si-Jie; Duan, Kai-Xuan; Yin, Cui-Cui; Chen, Hui; Yang, Chao; Xiong, Qing; Song, Qing-Xin; Lu, Xiang; Chen, Hao-Wei; Zhang, Wan-Ke; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2013-11-01

    Ethylene plays essential roles in adaptive growth of rice plants in water-saturating environment; however, ethylene signaling pathway in rice is largely unclear. In this study, we report identification and characterization of ethylene-response mutants based on the specific ethylene-response phenotypes of etiolated rice seedlings, including ethylene-inhibited root growth and ethylene-promoted coleoptile elongation, which is different from the ethylene triple-response phenotype in Arabidopsis. We establish an efficient system for screening and a set of rice mutants have been identified. Genetic analysis reveals that these mutants form eight complementation groups. All the mutants show insensitivity or reduced sensitivity to ethylene in root growth but exhibit differential responses in coleoptile growth. One mutant group mhz7 has insensitivity to ethylene in both root and coleoptile growth. We identified the corresponding gene by a map-based cloning method. MHZ7 encodes a membrane protein homologous to EIN2, a central component of ethylene signaling in Arabidopsis. Upon ethylene treatment, etiolated MHZ7-overexpressing seedlings exhibit enhanced coleoptile elongation, increased mesocotyl growth and extremely twisted short roots, featuring enhanced ethylene-response phenotypes in rice. Grain length was promoted in MHZ7-transgenic plants and 1000-grain weight was reduced in mhz7 mutants. Leaf senescent process was also affected by MHZ7 expression. Manipulation of ethylene signaling may improve adaptive growth and yield-related traits in rice.

  15. Dr.Phil. et Med. Hermann Von Schrötter: Skizzen eines feldarztes aus Montenegro- observations of a military physician on his visit to Montenegro.

    PubMed

    Vujovic, Veselin

    2008-01-01

    This essay gives a review of a book by an Austrian physician Hermann von Schrötter Skizzen Eines Feldartes aus Montenegro (Observations of a Military Physician from Montenegro), Berlin - Wien 1913 on the occasion of its translation to Montenegrin and reprint in Cetinje, Montenegro in 2007. The book takes us back to the time of the preparations and attack on Scutari, which took place in 1912 and 1913. The Montenegrin army achieved their military goal, but with numerous casualties, whose exact number has never been determined. The author, Hermann von Schrötter, confirmed this in his observations in the book. When the Montenegrin Red Cross asked for help, the organizations of the following countries responded: Austria, Czechoslovakia, England, France, The Netherlands, Italy, Germany, Russia, Switzerland, and Sweden. Apart from them, physicians were sent by the Slavonic Voluntary Society from St. Petersburg, the Boards of the Red Cross from Dubrovnik and Split, the National Board from Zadar; seven physicians came from the Bay of Boka and three physicians with three nurses came from Bosnia. I wish to stress that in those times the Red Cross offered aid, as it does today, to all the people in need, regardless of their political beliefs. The relations between Montenegro and Austria were poor back then, yet the Mission of the Austrian Red Cross generously gave assistance and relief to the Montenegrin people!

  16. A DELLA gene, RhGAI1, is a direct target of EIN3 and mediates ethylene-regulated rose petal cell expansion via repressing the expression of RhCesA2.

    PubMed

    Luo, Jing; Ma, Nan; Pei, Haixia; Chen, Jiwei; Li, Jing; Gao, Junping

    2013-11-01

    Ethylene plays an important role in organ growth. In Arabidopsis, ethylene can inhibit root elongation by stabilizing DELLA proteins. In previous work, it was found that ethylene suppressed cell expansion in rose petals, and five unisequences of DELLA genes are induced by ethylene. However, the mechanism of transcriptional regulation of DELLA genes by ethylene is still not clear. The results showed that the expression of RhGAI1 was induced in both ethylene-treated and ETR gene-silenced rose petals, and the promoter activity of RhGAI1 was strongly induced by RhEIN3-3 in Arabidopsis protoplasts. What is more, RhEIN3-3 could bind to the promoter of RhGAI1 directly in an electrophoretic mobility shift assay (EMSA). Cell expansion was suppressed in RhGAI1-Δ17-overexpressed Arabidopsis petals and promoted in RhGAI1-silenced rose petals. Moreover, in RhGAI1-silenced petals, the expression of nine cell expansion-related genes was clearly changed, and RhGAI1 can bind to the promoter of RhCesA2 in an EMSA. These results suggested that RhGAI1 was regulated by ethylene at the transcriptional level, and RhGAI1 was a direct target of RhEIN3-3. Also, RhGAI1 was shown to be involved in cell expansion partially through regulating the expression of cell expansion-related genes. Furthermore, RhCesA2 was a direct target of RhGAI1. This work uncovers the transcriptional regulation of RhGAI1 by ethylene and provides a better understanding of how ethylene regulates petal expansion in roses.

  17. A DELLA gene, RhGAI1, is a direct target of EIN3 and mediates ethylene-regulated rose petal cell expansion via repressing the expression of RhCesA2

    PubMed Central

    Gao, Junping

    2013-01-01

    Ethylene plays an important role in organ growth. In Arabidopsis, ethylene can inhibit root elongation by stabilizing DELLA proteins. In previous work, it was found that ethylene suppressed cell expansion in rose petals, and five unisequences of DELLA genes are induced by ethylene. However, the mechanism of transcriptional regulation of DELLA genes by ethylene is still not clear. The results showed that the expression of RhGAI1 was induced in both ethylene-treated and ETR gene-silenced rose petals, and the promoter activity of RhGAI1 was strongly induced by RhEIN3-3 in Arabidopsis protoplasts. What is more, RhEIN3-3 could bind to the promoter of RhGAI1 directly in an electrophoretic mobility shift assay (EMSA). Cell expansion was suppressed in RhGAI1-Δ17-overexpressed Arabidopsis petals and promoted in RhGAI1-silenced rose petals. Moreover, in RhGAI1-silenced petals, the expression of nine cell expansion-related genes was clearly changed, and RhGAI1 can bind to the promoter of RhCesA2 in an EMSA. These results suggested that RhGAI1 was regulated by ethylene at the transcriptional level, and RhGAI1 was a direct target of RhEIN3-3. Also, RhGAI1 was shown to be involved in cell expansion partially through regulating the expression of cell expansion-related genes. Furthermore, RhCesA2 was a direct target of RhGAI1. This work uncovers the transcriptional regulation of RhGAI1 by ethylene and provides a better understanding of how ethylene regulates petal expansion in roses. PMID:24014864

  18. IntegraTUM Teilprojekt E-Mail: Aufbau eines mandantenfähigen Groupware-Services und seine Integration in Identity Management und E-Mail Infrastruktur der Technischen Universität München

    NASA Astrophysics Data System (ADS)

    Diehn, Max

    Die E-Mail-Infrastruktur an der Technischen Universität München (TUM) ist historisch bedingt sehr heterogen und komplex. Viele Einrichtungen müssen wertvolle Arbeitskraft auf die Administration eigener Mailserver verwenden. Auf der anderen Seite wird bei einigen Einrichtungen der Ruf nach Groupware-Funktionalitäten wie z.B. gemeinsame Kalender immer lauter. Das Teilprojekt E-Mail stellt einen zentralen Mail- und Groupware-Service bereit, der den Einrichtungen ermöglichen soll, den Betrieb eigener Server und zugehöriger Systeme (etwa lokaler Benutzerverwaltungen) für diesen Zweck aufzugeben und diese Dienste an das Teilprojekt E-Mail zu migrieren, ohne ihre Verwaltungshoheit oder ihre Maildomains aufgeben zu müssen. Dieser Service versteht sich als eine Ergänzung zur bestehenden Grundversorgung der TUM mit den Maildiensten des myTUM-Mailers, ist mandantenfähig aufgebaut und kann daher künftig neben der TUM auch weiteren Organisationen im Münchner Wissenschaftsnetz zur Verfügung gestellt werden.

  19. Charakterisierung von Sulfotransferasen im Gastrointestinaltrakt von Mensch und Ratte und Aktivierung von Promutagenen in V79-Zellen, die eine intestinale Form (1B1) des Menschen und der Ratte exprimieren

    NASA Astrophysics Data System (ADS)

    Teubner, Wera

    2001-05-01

    Die Ausstattung der gastrointestinalen Mukosa des Menschen und der Ratte mit Sulfotransferasen wurde mit Hilfe von Immunodetektion und Enzymaktivitätsmessungen untersucht. In Proben aus Colon und Rektum von 39 Personen wurden die Formen h1A1, h1A3 und h1B1 identifiziert, wobei in einer weiteren Probe, die als einzige von einem an Colitis Ulcerosa erkrankten Patienten stammte, keine Sulfotransferasen nachgewiesen werden konnten. Bei der Immunblot-Analyse war das Expressionsmuster der einzelnen Formen in allen Proben ähnlich. In wenigen Proben waren die relativen Signalintensitäten der h1A1 und der h1B1 um die Hälfte erniedrigt. Der Gehalt von SULT an zytosolischem Protein zeigte einen bis zu 8 - 10fachen Unterschied, er betrug jedoch bei zwei Dritteln der Proben zwischen 0,15 und 0,3 (h1A1 und h1A3) bzw. 0,6 und 0,8 Promille (h1B1). Die Variation konnte nicht auf Alter, Geschlecht oder Krankheitsbild der Patienten zurückgeführt werden. Auch der für die allelischen Varianten der h1A1 beschriebene Effekt auf die Enzymaktiviät bzw. Stabilität konnte in der Menge an immunreaktivem Protein nicht in diesem Ausma detektiert werden. Die Allelhäufigkeit von h1A1*R und h1A1*H war gegenüber der gesunden Bevölkerung nicht verändert. In den sieben Proben aus dem Dünndarm (Coecum, viermal Ileum, Jejunum) konnten zusätzlich die Formen h1E1 und h2A1 identifiziert werden. Ein möglicherweise der Form h1C1 entsprechendes Protein wurde im Magen detektiert. Im Vergleich zum Menschen war die Expression in der Ratte stärker auf die Leber konzentriert. Während beim Menschen in allen untersuchten Abschnitten Sulfotransferasen in Mengen detektiert wurden, die in zwei Fällen (h1B1 und h1A3) sogar den Gehalt in der Leber überstiegen, beschränkte sich die Expression in der Ratte auf im Vergleich zur Leber geringe Mengen im Magen und Dickdarm. Nachgewiesen wurden die r1B1, r1A1 sowie eine nicht identifizierte Form von 35kD, bei der es sich vermutlich um die r1C2 handelt. Im

  20. 2016 CAPS ethics session/Ein debate: 1. Regionalization of pediatric surgical care 2. Ethical introduction of surgical innovation 3. Addressing stress in a surgical practice: resiliency, well-being, and burnout.

    PubMed

    Bagwell, Charles E; Chiu, Priscilla; Fecteau, Annie; Gow, Kenneth W; Mueller, Claudia M; Price, David; Zigman, Andrew F

    2017-05-01

    The following is the conference proceeding of the Second Ein Debate from the 48th Annual Meeting of the Canadian Association of Paediatric Surgeons held in Vancouver, BC, from September 22 to 24, 2016. The three main topics for debate, as prepared by the members of the CAPS Ethics Committee, are: 1. Regionalization of care: pros and cons, 2. Innovation in clinical care: ethical considerations, and 3. Surgeon well-being: caring for the caregiver. The authors of this paper, as participants in the debate, were assigned their positions at random. Therefore, the opinions they express within this summary might not reflect their own viewpoints. In the first discussion, arguments for and against the regionalization of pediatric surgical care are discussed, primarily in the context of a case of BA. In the pro argument, the evidence and lessons learned from different European countries are explored as well as different models to provide the best BA care outside of large teaching centers. In the counterargument, the author explains how regionalization of care could be detrimental for the patient, the family, the regional center, and for the health care system in general. In the debate on surgical innovation the authors define surgical innovation. They review the pertinent ethical principles, explore a model for its implementation, and the role of the institution at which the innovation is proposed. In the third section, surgeon well-being is examined, and recent literature on surgeon resiliency and burnout both at the attending and resident level is reviewed. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Performance of innovative textile biofilters for domestic wastewater treatment.

    PubMed

    Spychała, Marcin; Błazejewski, Ryszard; Nawrot, Tadeusz

    2013-01-01

    Two types of geotextile, TS 50 and TC/PP 300, were investigated as experimental filters. The raw wastewater, pre-treated in a septic tank, was intermittently dosed and filtered under hydrostatic pressure. At the beginning, the filter reactor comprised nine filters made of geotextiles (of three types: TS 10, TS 50 and TC/PP 300). At the end of the start-up period the TS 10 filters were removed due to their high outflow instability. After four months of working, the hydraulic capacities of the remaining filters were: 3.23 cm3/cm2/d for TS 50 and 4.14 cm3/cm2/d for TC/PP 300. The efficiencies of COD and BOD5 removal were similar for both types of geotextile (COD: 64%, BOD5: 80%). A small but statistically significant difference between ammonium nitrogen removal was observed (40% for TS 50 and 35% for TC/PP 300), most probably due to their different structure. Biological removal of P(tot) was relatively poor and similar for both geotextile types. The mean concentration of matter accumulated on the geotextiles was over one order of magnitude higher than conventional activated sludge concentrations. During the last weeks of the experiments the values of basic pollution indicators in the effluent were lower than the maximum permissible values (according to Polish law).

  2. Heterotrophic denitrification of aquaculture effluent using fluidized sand biofilters

    USDA-ARS?s Scientific Manuscript database

    The ability to consistently and cost-effectively reduce nitrate-nitrogen loads in effluent from recirculating aquaculture systems would enhance the industry's environmental stewardship and allow improved facility proximity to large markets in sensitive watersheds. Heterotrophic denitrification techn...

  3. Experimental study on nitrification in a submerged aerated biofilter.

    PubMed

    Farabegoli, G; Chiavola, A; Rolle, E; Stracquadanio, S

    2004-01-01

    The aim of the present work was to evaluate the performance of a semi-pilot scale BAF in order to obtain a highly polished effluent in terms of removal of organic matter, suspended solids and ammonia and to observe the influence of temperature, pH and nitrite accumulation on the nitrification process. The ammonia removal efficiency during summer and winter and the nitrite accumulation in presence of free ammonia were observed. The biomass density was measured at different filter bed heights and the sludge production from the effluent of the backwashing water was evaluated. The results obtained were used to calibrate a mathematical model for the prediction of the ammonia removal profile in the filter bed and of biomass thickness.

  4. Microbial Removals by a Novel Biofilter Water Treatment System

    PubMed Central

    Wendt, Christopher; Ives, Rebecca; Hoyt, Anne L.; Conrad, Ken E.; Longstaff, Stephanie; Kuennen, Roy W.; Rose, Joan B.

    2015-01-01

    Two point-of-use drinking water treatment systems designed using a carbon filter and foam material as a possible alternative to traditional biosand systems were evaluated for removal of bacteria, protozoa, and viruses. Two configurations were tested: the foam material was positioned vertically around the carbon filter in the sleeve unit or horizontally in the disk unit. The filtration