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Sample records for aeration tank settling

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

    DEFF Research Database (Denmark)

    Nielsen, M. K.; Bechmann, H.; Henze, Mogens

    2000-01-01

    The use of aeration tank settling during high hydraulic loads on large wastewater treatment plants has previously been demonstrated as a reliable technique and proven valuable. The paper proposes a simplified deterministic model to predict the efficiency of the method. It is shown that a qualitat......The use of aeration tank settling during high hydraulic loads on large wastewater treatment plants has previously been demonstrated as a reliable technique and proven valuable. The paper proposes a simplified deterministic model to predict the efficiency of the method. It is shown that a...

  2. Computational Fluid Dynamics Modelling of Hydraulics and Sedimentation in Process Reactors during Aeration Tank Settling

    DEFF Research Database (Denmark)

    Jensen, M.D.; Ingildsen, P.; Rasmussen, Michael R.;

    2006-01-01

    Aeration tank settling is a control method allowing settling in the process tank during highhydraulic load. The control method is patented. Aeration tank settling has been applied in several wastewater treatment plants using the present design of the process tanks. Some process tank designs...... and outletcausing a disruption of the sludge blanket at the outlet and thereby reducing the retention of sludge in theprocess tank. The model has allowed us to establish a clear picture of the problems arising at the plantduring aeration tank settling. Secondly, several process tank design changes...

  3. Computational Fluid Dynamics Modelling of Hydraulics and Sedimentation in Process Reactors During Aeration Tank Settling

    DEFF Research Database (Denmark)

    Dam Jensen, Mette; Ingildsen, Pernille; Rasmussen, Michael R.;

    2005-01-01

    Aeration Tank Settling is a control method alowing settling in the process tank during high hydraulic load. The control method is patented. Aeration Tank Settling has been applied in several waste water treatment plant's using present design of the process tanks. Some process tank designs have...... and outlet causing a disruption of the sludge blanket at the outlet and thereby reducing the retention of sludge in the process tank. The model has allowed us to establish a clear picture of the problems arising at the plant during Aeration Tank Settling. Secondly, several process tank design changes...

  4. Numerical Modelling of Flow and Settling in Secondary Settling Tanks

    DEFF Research Database (Denmark)

    Dahl, Claus Poulsen

    This thesis discusses the development of a numerical model for the simulation of secondary settling tanks. In the first part, the status on the development of numerical models for settling tanks and a discussion of the current design practice are presented. A study of the existing numerical models...

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

    Institute of Scientific and Technical Information of China (English)

    Xiaohong Zhou; Yuanyuan Wu; Hanchang Shi; Yanqing Song

    2013-01-01

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

  6. Phosphorus removal in aerated stirred tank reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ghigliazza, R.; Lodi, A.; Rovatti, M. [Inst. of Chemical and Process Engineering ``G.B. Bonino``, Univ. of Genoa (Italy)

    1999-03-01

    The possibility to obtain biological phosphorus removal in strictly aerobic conditions has been investigated. Experiments, carried out in a continuous stirred tank reactor (CSTR), show the feasibility to obtain phosphorus removal without the anaerobic phase. Reactor performance in terms of phosphorus abatement kept always higher then 65% depending on adopted sludge retention time (SRT). In fact increasing SRT from 5 days to 8 days phosphorus removal and reactor performance increase but overcoming this SRT value a decreasing in reactor efficiency was recorded. (orig.) With 6 figs., 3 tabs., 18 refs.

  7. Tank 21 and Tank 24 Blend and Feed Study: Blending Times, Settling Times, and Transfers

    International Nuclear Information System (INIS)

    The Salt Disposition Integration (SDI) portfolio of projects provides the infrastructure within existing Liquid Waste facilities to support the startup and long term operation of the Salt Waste Processing Facility (SWPF). Within SDI, the Blend and Feed Project will equip existing waste tanks in the Tank Farms to serve as Blend Tanks where salt solutions of up to 1.2 million gallons will be blended in 1.3 million gallon tanks and qualified for use as feedstock for SWPF. In particular, Tanks 21 and 24 are planned to be used for blending and transferring to the SDI feed tank. These tanks were evaluated here to determine blending times, to determine a range of settling times for disturbed sludge, and to determine that the SWPF Waste Acceptance Criteria that less than 1200 mg/liter of solids will be entrained in salt solutions during transfers from the Tank 21 and Tank 24 will be met. Overall conclusions for Tank 21 and Tank 24 operations include: (1) Experimental correction factors were applied to CFD (computational fluid dynamics) models to establish blending times between approximately two and five hours. As shown in Phase 2 research, blending times may be as much as ten times greater, or more, if lighter fluids are added to heavier fluids (i.e., water added to salt solution). As the densities of two salt solutions converge this effect may be minimized, but additional confirmatory research was not performed. (2) At the current sludge levels and the presently planned operating heights of the transfer pumps, solids entrainment will be less than 1200 mg/liter, assuming a conservative, slow settling sludge simulant. (3) Based on theoretical calculations, particles in the density range of 2.5 to 5.0 g/mL must be greater than 2-4 (micro)m in diameter to ensure they settle adequately in 30-60 days to meet the SWPF feed criterion ( 60 days) settling times in Tank 21.

  8. Relative importance of secondary settling tank models in WWTP simulations

    DEFF Research Database (Denmark)

    Ramin, Elham; Flores-Alsina, Xavier; Sin, Gürkan;

    2012-01-01

    Results obtained in a study using the Benchmark Simulation Model No. 1 (BSM1) show that a one-dimensional secondary settling tank (1-D SST) model structure and its parameters are among the most significant sources of uncertainty in wastewater treatment plant (WWTP) simulations [Ramin et al., 2011...... simulations (SRC method); and (b) Morris screening. The overall objective of assessing the 1-D SST model selection and parameters in GSA is to provide a parameter sensitivity ranking for WWTP calibration exercises, aiming at predicting key plant performance criteria, including methane production and effluent...... water quality index. Results obtained in this study show that, 1-D SST model parameters strongly influence biogas production via anaerobic digestion and the plant’s effluent water quality, but they have limited effect on estimating the quality of nitrogen rich returns from the digester....

  9. EXPERIMENTAL AND NUMERICAL SIMULATION OF THREE-PHASE FLOW IN AN AERATION TANK

    Institute of Scientific and Technical Information of China (English)

    Cheng Wen; Zhou Xiao-de; Song Ce; Min Tao; Murai Yuichi; Yamamoto Fujio

    2003-01-01

    Aeration plays an important role in the treatment of activated sludge due to the interactions among bubbles, sewage and activated sludge in an aeration tank. The aeration performance is directly concerned with the efficiency of sewage disposal. So the three-dimensional two-fluid model was established with emphasis on the phase interaction terms in this paper. This model, as an extension of the two-phase flow model, involved the motion laws of three-phases, and was compared with experimental studies. The finite volume method was used in the numerical simulation of gas-liquid two-phase flow and gas-liquid-solid three-phase flow. In order to discuss the influence of gas-phase, liquid-phase and solid-phase motions in an aeration tank on the sewage disposal, three kinds of boundary and initial conditions were adopted. The simulated results of the flow structure show qualitatively good agreement with the experimental data. And the theoretical basis for designing the best aeration tank was discussed according to the simulated results.

  10. Processes to improve energy efficiency during pumping and aeration of recirculating water in circular tank systems

    Science.gov (United States)

    Conventional gas transfer technologies for aquaculture systems occupy a large amount of space, require considerable capital investment, and can contribute to high electricity demand. In addition, diffused aeration in a circular tank can interfere with the hydrodynamics of water rotation and the spee...

  11. Characterization of a hydraulic flow in the aeration tanks of Suzano wastewater treatment by using radioactive tracer, Sao Paulo State, Brazil

    International Nuclear Information System (INIS)

    Previous studies carried out by Suzano's Wastewater Treatment Station staff responsible for its operation and optimization indicated a mixing efficiency reduction of the existing aeration system, (Filstar superficial mechanical aerator). In this work instantaneous injection of radioactive tracer, bromine-82, was used in order to determine the mean residence time - MRT and dispersion numbers, in actual scale, with the objective of verifying the hydraulic flow behavior and the possible existence of dead zones in the Suzano Station aeration tanks, operating with different aeration systems: ABS submersible aerators, Frings System (tank A) and Filstar aerators (tank D). The obtained results showed that all essayed tanks have their hydraulic flow modeled by only one mixed reactor with dispersion numbers close to 1,0 ( 0,9473 and 0,9403 respectively ), and did not present dead zones. The best homogenization was reached in tank A operated with ABS aerators. (author)

  12. A consistent modelling methodology for secondary settling tanks in wastewater treatment.

    Science.gov (United States)

    Bürger, Raimund; Diehl, Stefan; Nopens, Ingmar

    2011-03-01

    The aim of this contribution is partly to build consensus on a consistent modelling methodology (CMM) of complex real processes in wastewater treatment by combining classical concepts with results from applied mathematics, and partly to apply it to the clarification-thickening process in the secondary settling tank. In the CMM, the real process should be approximated by a mathematical model (process model; ordinary or partial differential equation (ODE or PDE)), which in turn is approximated by a simulation model (numerical method) implemented on a computer. These steps have often not been carried out in a correct way. The secondary settling tank was chosen as a case since this is one of the most complex processes in a wastewater treatment plant and simulation models developed decades ago have no guarantee of satisfying fundamental mathematical and physical properties. Nevertheless, such methods are still used in commercial tools to date. This particularly becomes of interest as the state-of-the-art practice is moving towards plant-wide modelling. Then all submodels interact and errors propagate through the model and severely hamper any calibration effort and, hence, the predictive purpose of the model. The CMM is described by applying it first to a simple conversion process in the biological reactor yielding an ODE solver, and then to the solid-liquid separation in the secondary settling tank, yielding a PDE solver. Time has come to incorporate established mathematical techniques into environmental engineering, and wastewater treatment modelling in particular, and to use proven reliable and consistent simulation models. PMID:21334042

  13. Research advances and challenges in one-dimensional modeling of secondary settling tanks--a critical review.

    Science.gov (United States)

    Li, Ben; Stenstrom, M K

    2014-11-15

    Sedimentation is one of the most important processes that determine the performance of the activated sludge process (ASP), and secondary settling tanks (SSTs) have been frequently investigated with the mathematical models for design and operation optimization. Nevertheless their performance is often far from satisfactory. The starting point of this paper is a review of the development of settling theory, focusing on batch settling and the development of flux theory, since they played an important role in the early stage of SST investigation. The second part is an explicit review of the established 1-D SST models, including the relevant physical law, various settling behaviors (hindered, transient, and compression settling), the constitutive functions, and their advantages and disadvantages. The third part is a discussion of numerical techniques required to solve the governing equation, which is usually a partial differential equation. Finally, the most important modeling challenges, such as settleability description, settling behavior understanding, are presented. PMID:25090623

  14. Oxygen Mass Transfer in an Aerated Stirred Tank with Double Impellers: A Generalized Correlation Including Spacing Impact

    Directory of Open Access Journals (Sweden)

    Hayder Mohammed Issa

    2016-01-01

    Full Text Available Stirred aerated tanks by double impellers are used in fermentation and various biological processes for water treatment, food industry, and pharmaceutical production. In this study, a generalized correlation model was developed for the dependent parameter (kla/N. The oxygen mass transfer from air to liquid takes place by rotating the double impellers (IBRC and PBPU in the aerated tank. This model considers Reynolds number, Froude number, power number, the liquid height, and the spacing between impellers as the most significant specifications that are related to aerated tank performance. The spacing between the impellers is considered to be a design factor of such industrial equipment due to its remarkable impact on the oxygen mass transfer.

  15. Three-dimensional numerical simulation of settling and resuspension of solids in storage tanks with air injection recirculators

    International Nuclear Information System (INIS)

    Transient three-dimensional finite-difference numerical modeling of flow with settling solids in a 3.7 x 103 m3 tank was performed. The number-average diameter of the particles was 15μm and nominal volumetric concentration was 24 percent. Using dilute suspension, concentration dependent viscosity, and settling velocity assumption, modeled air lift circulators were shown to be sufficient to maintain solids in suspension during normal operation. Resuspension of solids was also shown to be accomplished by impulsive circulator startup in the absence of particle agglomeration. Settling velocity was shown to be a dominant parameter under the assumptions made

  16. Development of a CFD Model for Secondary Final Settling Tanks in Water Pollution Control Plants

    Science.gov (United States)

    Gong, Minwei; Xanthos, Savvas; Ramalingam, Krish; Fillos, John

    2007-11-01

    To assess performance and evaluate alternatives to improve efficiency of the New York City the Wards Island Water Pollution Control Plant (WPCP) FSTs at peak loads, a 3D CFD model has been developed. Fluent was utilized as the base platform, where sub-models of the Suspended Solids (SS), settling characteristics, density currents and SS flocculation were incorporated. This was supplemented by field and bench scale experiments to quantify the coefficients integral to the sub-models. Model calibration and validation have been carried out by using the extensive set of data collected. The model can be used to evaluate different modes of operation, alternate hydraulic and solids loading rates, as well as addition of auxiliary components such as baffles to improve process performance. The model is being used to compare potential benefits for different alternatives of design and operation of the existing FSTs. After comparing series of inlet baffles, a baffle with 4 horizontal and 7 vertical slots has been recommended for installation in the FSTs. Additional baffle type, configurations and locations within the tank are also being evaluated to improve the performance of the FSTs especially during periods of poor settling and peak flow conditions.

  17. Bench-scale enhanced sludge washing and gravity settling of Hanford Tank C-106 Sludge

    International Nuclear Information System (INIS)

    This report summarizes the results of a bench-scale sludge pretreatment demonstration of the Hanford baseline flowsheet using liter-quantities of sludge from Hanford Site single-shell tank 241-C-106 (tank C-106). The leached and washed sludge from these tests provided Envelope D material for the contractors supporting Tank Waste Remediation System (TWRS) Privatization. Pretreatment of the sludge included enhanced sludge washing and gravity settling tests and providing scale-up data for both these unit operations. Initial and final solids as well as decanted supernatants from each step of the process were analyzed chemically and radiochemically. The results of this work were compared to those of Lumetta et al. (1996a) who performed a similar experiment with 15 grams of C-106, sludge. A summary of the results are shown in Table S.1. Of the major nonradioactive components, those that were significantly removed with enhanced sludge washing included aluminum (31%), chromium (49%), sodium (57%), and phosphorus (35%). Of the radioactive components, a significant amount of 137Cs (49%) were removed during the enhanced sludge wash. Only a very small fraction of the remaining radionuclides were removed, including 90Sr (0.4%) and TRU elements (1.5%). These results are consistent with those of the screening test. All of the supernatants (both individually and as a blend) removed from these washing steps, once vitrified as LLW glasses (at 20 wt% Na2O), would be less than NRC Class C in TRU elements and less than NRC Class B in 90Sr

  18. In-tank aeration, a necessary compliment of loaded systems in an airlift recirculating aquaculture system

    Science.gov (United States)

    Water treatment components in recirculating aquaculture systems in generally address solids removal, nitrification, circulation, aeration, and degasification. Airlift pumps in a recirculating aquaculture system can address water circulation, aeration, and degasification. Recent data indicates oxygen...

  19. STUDY ON APPLICATION OF AERATION BIOLOGICAL FLUID TANK TECHNOLGY IN NH4+—N WASTE WATER TREATMENT

    Institute of Scientific and Technical Information of China (English)

    CHENYi; LUJian-guo

    2003-01-01

    This paper introduces an application of "Aeration biological fluid tank"technology (ABFT) for the treatment of waste water containing NH4+-N and high concentrated chemicals.Highlights were focused on the effects of dissolved oxygen,pH,temperature and retention time on waste water bilogical treatment in order to find out a new approach in treatment of waste time on containing high concentrated NH4+-N.

  20. Significance of uncertainties derived from settling tank model structure and parameters on predicting WWTP performance - A global sensitivity analysis study

    DEFF Research Database (Denmark)

    Ramin, Elham; Sin, Gürkan; Mikkelsen, Peter Steen;

    2011-01-01

    Uncertainty derived from one of the process models – such as one-dimensional secondary settling tank (SST) models – can impact the output of the other process models, e.g., biokinetic (ASM1), as well as the integrated wastewater treatment plant (WWTP) models. The model structure and parameter...... from the last aerobic bioreactor upstream to the SST (Garrett/hydraulic method). For model structure uncertainty, two one-dimensional secondary settling tank (1-D SST) models are assessed, including a first-order model (the widely used Takács-model), in which the feasibility of using measured...... parameters for calibration is limited. The other SST model is a state-of-the-art, second-order, convection-dispersion tool (Plósz et al., 2007). The sensitivity results obtained from the four scenarios consistently indicate that the settler models and their parameters are among the most significant sources...

  1. Research on jet mixing of settled sludges in nuclear waste tanks at Hanford and other DOE sites: A historical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Powell, M.R.; Onishi, Y.; Shekarriz, R.

    1997-09-01

    Jet mixer pumps will be used in the Hanford Site double-shell tanks to mobilize and mix the settled solids layer (sludge) with the tank supernatant liquid. Predicting the performance of the jet mixer pumps has been the subject of analysis and testing at Hanford and other U.S. Department of Energy (DOE) waste sites. One important aspect of mixer pump performance is sludge mobilization. The research that correlates mixer pump design and operation with the extent of sludge mobilization is the subject of this report. Sludge mobilization tests have been conducted in tanks ranging from 1/25-scale (3 ft-diameter) to full scale have been conducted at Hanford and other DOE sites over the past 20 years. These tests are described in Sections 3.0 and 4.0 of this report. The computational modeling of sludge mobilization and mixing that has been performed at Hanford is discussed in Section 5.0.

  2. Research on jet mixing of settled sludges in nuclear waste tanks at Hanford and other DOE sites: A historical perspective

    International Nuclear Information System (INIS)

    Jet mixer pumps will be used in the Hanford Site double-shell tanks to mobilize and mix the settled solids layer (sludge) with the tank supernatant liquid. Predicting the performance of the jet mixer pumps has been the subject of analysis and testing at Hanford and other U.S. Department of Energy (DOE) waste sites. One important aspect of mixer pump performance is sludge mobilization. The research that correlates mixer pump design and operation with the extent of sludge mobilization is the subject of this report. Sludge mobilization tests have been conducted in tanks ranging from 1/25-scale (3 ft-diameter) to full scale have been conducted at Hanford and other DOE sites over the past 20 years. These tests are described in Sections 3.0 and 4.0 of this report. The computational modeling of sludge mobilization and mixing that has been performed at Hanford is discussed in Section 5.0

  3. 污水站曝气沉淀池改造%Renovation on sedimentation tank sewage aeration station

    Institute of Scientific and Technical Information of China (English)

    居鹏飞; 吴志峰

    2016-01-01

    对曝气沉淀池中心导流管进行改造,重新设计中心导流管长度,确定中心导流管喇叭口尺寸,加装底部反射板,使整个污水处理系统运行更加平稳高效。%The central draft tube sedimentation tanks aeration transform redesigned center draft tube length to determine the center of the draft tube flare size, the installation of the bottom of the reflector plate, the entire sewage treatment system run more smoothly and efficiently.

  4. Pengaruh Jumlah Pemakaian Air Di Continuous Settling Tank Terhadap Potensi Minyak Yang Dihasilkan Dan Kadar Minyak Hilang

    OpenAIRE

    Zuhairi, Novia

    2011-01-01

    The process separate oil in Continuous Settling Tank (CST) will get oil and sludge has been separated according to density. One of the important factor must give more attention is using dilute water which influence with measure of oil losses and the result of potential oil. Analysis potential of oil has been done with kind of presentation water are 24%, 27% and 30% using centrifuge method. Extraction methode for analysis measure of oil losses using n-hexane. The result of analysis is using w...

  5. Bench-scale feasibility testing of pulsed-air technology for in-tank mixing of dry cementitious solids with tank liquids and settled solids

    International Nuclear Information System (INIS)

    This report documents the results of testing performed to determine the feasibility of using a pulsed-air mixing technology (equipment developed by Pulsair Systems, Inc., Bellevue, WA) to mix cementitious dry solids with supernatant and settled solids within a horizontal tank. The mixing technology is being considered to provide in situ stabilization of the open-quotes Vclose quotes tanks at the Idaho National Engineering and Environmental Laboratory (INEEL). The testing was performed in a vessel roughly 1/6 the scale of the INEEL tanks. The tests used a fine soil to simulate settled solids and water to simulate tank supernatants. The cementitious dry materials consisted of Portland cement and Aquaset-2H (a product of Fluid Tech Inc. consisting of clay and Portland cement). Two scoping tests were conducted to allow suitable mixing parameters to be selected. The scoping tests used only visual observations during grout disassembly to assess mixing performance. After the scoping tests indicated the approach may be feasible, an additional two mixing tests were conducted. In addition to visual observations during disassembly of the solidified grout, these tests included addition of chemical tracers and chemical analysis of samples to determine the degree of mixing uniformity achieved. The final two mixing tests demonstrated that the pulsed-air mixing technique is capable of producing slurries containing substantially more cementitious dry solids than indicated by the formulations suggested by INEEL staff. Including additional cement in the formulation may have benefits in terms of increasing mobilization of solids, reducing water separation during curing, and increasing the strength of the solidified product. During addition to the tank, the cementitious solids had a tendency to form clumps which broke down with continued mixing

  6. DEMONSTRATION OF MIXING AND TRANSFERRING SETTLING COHESIVE SLURRY SIMULANTS IN THE AY-102 TANK

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D.; Gauglitz, P.

    2012-01-03

    In support of Hanford's feed delivery of high level waste (HLW) to the Waste Treatment and Immobilization Plant (WTP), pilot-scale testing and demonstrations with simulants containing cohesive particles were performed as a joint collaboration between Savannah River National Laboratory (SRNL) and the Pacific Northwest National Laboratory (PNNL) staff. The objective of the demonstrations was to determine the impact that cohesive particle interactions in the simulants, and the resulting non-Newtonian rheology, have on tank mixing and batch transfer of large and dense seed particles. The work addressed the impacts cohesive simulants have on mixing and batch transfer performance in a pilot-scale system. Kaolin slurries with a range of wt% concentrations to vary the Bingham yield stress were used in all the non-Newtonian simulants. To study the effects of just increasing the liquid viscosity (no yield stress) on mixing and batch transfers, a glycerol/water mixture was used. Stainless steel 100 micron particles were used as seed particles due to their density and their contrasting color to the kaolin and glycerol. In support of Hanford's waste certification and delivery of tank waste to the Waste Treatment and Immobilization Plant (WTP), Savannah River National Laboratory (SRNL) was tasked by Washington River Protection Solutions (WRPS) to evaluate the effectiveness of mixing and transferring tank waste in a Double Shell Tank (DST) to the WTP Receipt Tank. The work addresses the impacts cohesive simulants have on mixing and batch transfer performance. This work is follow-on to the previous tasks 'Demonstration of Mixer Jet Pump Rotational Sensitivity on Mixing and Transfers of the AY-102 Tank' and 'Demonstration of Simulated Waste Transfers from Tank AY-102 to the Hanford Waste Treatment Facility'. The cohesive simulants were investigated and selected jointly by SRNL and PNNL and a white paper was written on this evaluation. The testing and

  7. Influence of selecting secondary settling tank sub-models on the calibration of WWTP models – A global sensitivity analysis using BSM2

    DEFF Research Database (Denmark)

    Ramin, Elham; Flores Alsina, Xavier; Sin, Gürkan;

    2014-01-01

    This study investigates the sensitivity of wastewater treatment plant (WWTP) model performance to the selection of one-dimensional secondary settling tanks (1-D SST) models with first-order and second-order mathematical structures. We performed a global sensitivity analysis (GSA) on the benchmark...... settling parameters were found to be as influential as the biokinetic parameters on the uncertainty of WWTP model predictions, particularly for biogas production and treated water quality. However, the sensitivity measures were found to be dependent on the 1-D SST models selected. Accordingly, we suggest a...... different optimum parameter selection for the calibration of WWTP models when either of the 1-D SST models is used. Using first-order models, the calibration should give equal importance to the adjustment of the hindered settling and slow settling parameter values. The adjusted hindered settling parameters...

  8. Sidewall-box airlift pump provides large flows for aeration, CO2 stripping, and water rotation in large dual-drain circular tanks

    Science.gov (United States)

    Conventional gas transfer technologies for aquaculture systems occupy a large amount of space, require a considerable capital investment, and can contribute to high electricity demand. In addition, diffused aeration in a circular culture tank can interfere with the hydrodynamics of water rotation a...

  9. Tank 241-AZ-101 steam bumping and settling Process Test report

    International Nuclear Information System (INIS)

    This report summarizes the process test in which the airlift circulators in Tank 241-AZ-101 were shutdown. The test was successful, in that no extreme temperature excursions occurred. Only general data was obtianed through the use of a gamma energy probe

  10. Modelling of the Bubble Size Distribution in an Aerated Stirred Tank: Theoretical and Numerical Comparison of Different Breakup Models

    Directory of Open Access Journals (Sweden)

    Kálal Zbyněk

    2014-09-01

    Full Text Available The main topic of this study is the mathematical modelling of bubble size distributions in an aerated stirred tank using the population balance method. The air-water system consisted of a fully baffled vessel with a diameter of 0.29 m, which was equipped with a six-bladed Rushton turbine. The secondary phase was introduced through a ring sparger situated under the impeller. Calculations were performed with the CFD software CFX 14.5. The turbulent quantities were predicted using the standard k-ε turbulence model. Coalescence and breakup of bubbles were modelled using the MUSIG method with 24 bubble size groups. For the bubble size distribution modelling, the breakup model by Luo and Svendsen (1996 typically has been used in the past. However, this breakup model was thoroughly reviewed and its practical applicability was questioned. Therefore, three different breakup models by Martínez-Bazán et al. (1999a, b, Lehr et al. (2002 and Alopaeus et al. (2002 were implemented in the CFD solver and applied to the system. The resulting Sauter mean diameters and local bubble size distributions were compared with experimental data.

  11. Interdependences between flow patterns and oxygen entry in aeration tanks of wastewater treatment plants; Der Zusammenhang von Stroemungsstrukturen und Sauerstoffeintrag bei druckbeluefteten Belebungsbecken

    Energy Technology Data Exchange (ETDEWEB)

    Thiersch, B.

    2001-07-01

    The flow field, turbulence intensities and the distribution of the relative gas-holdup of aeration tanks of operating wastewater treatment plants were investigated experimentally with Acoustic-Doppler-Velocimeter probes. Based on the experimental results a hydrodynamical model in Euler-Euler-Formulation was developed and numerical studies of different tank and diffuser arrangements were performed. It was found that the flow pattern is mainly influenced by the gas sparger arrangement and the tank aspect-ratio. Combining the experimental and numerical results reasons for different aeration efficiencies were identified. Increasing the diffuser density changed the flow field from the spiral type to the cellular pattern with instable and dynamical structures. These flow patterns improved the aeration efficiency by increasing the residence time of the bubbles and the recirculating flows. (orig.) [German] In der vorliegenden Arbeit werden grundlegende Stroemungsstrukturen von druckbeluefteten Belebungsbecken anhand messtechnischer Untersuchungen der Geschwindigkeitsverteilungen, Turbulenzgroessen und relativer Gasgehaltsverteilungen von Belebungsbecken im Betriebszustand aufgezeigt. Vorab wird die Einsatzfaehigkeit von Akkustik-Doppler-Sonden in dispersen Zweiphasenstroemungen detailliert ueberprueft. Aufbauend auf den Messergebnissen wird ein numerisches Simulationsprogramm zur dynamischen Berechnung unterschiedlicher Beckenkonfigurationen entwickelt. Aus den experimentellen Ergebnissen in Verbindung mit den Berechnungsergebnissen sowie den Auswertungen frueherer Untersuchungen konnten hydromechanische Ursachen der unterschiedlichen Sauerstoffeintragseffizienz bei verschiedenen Beckenkonzeptionen abgeleitet werden. Dabei stellen die Anordnung sowie Gleichverteilung der Belueftungselemente sowie das Querschnittsverhaeltnis der Belebungsbecken die wesentlichen Einflussgroessen auf die Ausbildung der Stroemungsstrukturen dar. Mit zunehmender Belegungsdichte und

  12. Influence of aeration-homogenization system in stirred tank bioreactors, dissolved oxygen concentration and pH control mode on BHK-21 cell growth and metabolism.

    Science.gov (United States)

    Núñez, Eutimio Gustavo Fernández; Leme, Jaci; de Almeida Parizotto, Letícia; Chagas, Wagner Antonio; de Rezende, Alexandre Gonçalves; da Costa, Bruno Labate Vale; Monteiro, Daniela Cristina Ventini; Boldorini, Vera Lucia Lopes; Jorge, Soraia Attie Calil; Astray, Renato Mancini; Pereira, Carlos Augusto; Caricati, Celso Pereira; Tonso, Aldo

    2014-08-01

    This work focused on determining the effect of dissolved oxygen concentration (DO) on growth and metabolism of BHK-21 cell line (host cell for recombinant proteins manufacturing and viral vaccines) cultured in two stirred tank bioreactors with different aeration-homogenization systems, as well as pH control mode. BHK-21 cell line adapted to single-cell suspension was cultured in Celligen without aeration cage (rotating gas-sparger) and Bioflo 110, at 10, 30 and 50 % air saturation (impeller for gas dispersion from sparger-ring). The pH was controlled at 7.2 as far as it was possible with gas mixtures. In other runs, at 30 and 50 % (DO) in Bioflo 110, the cells grew at pH controlled with CO2 and NaHCO3 solution. Glucose, lactate, glutamine, and ammonium were quantified by enzymatic methods. Cell concentration, size and specific oxygen consumption were also determined. When NaHCO3 solution was not used, the optimal DOs were 10 and 50 % air saturation for Celligen and Bioflo 110, respectively. In this condition maximum cell concentrations were higher than 4 × 10(6) cell/mL. An increase in maximum cell concentration of 36 % was observed in batch carried out at 30 % air saturation in a classical stirred tank bioreactor (Bioflo 110) with base solution addition. The optimal parameters defined in this work allow for bioprocess developing of viral vaccines, transient protein expression and viral vector for gene therapy based on BHK-21 cell line in two stirred tank bioreactors with different agitation-aeration systems. PMID:23846480

  13. Protozoan Fauna and Abundance in Aeration Tanks of Three Municipal Wastewater Treatment Plants in the Eastern Cape Province of South Africa

    Science.gov (United States)

    Sibewu, M.; Momba, M. N. B.; Okoh, A. L.

    This study focuses on the assessment of the protozoan fauna and abundance in the mixed liquors of aeration tanks of the three municipal wastewater treatment plants located in Fort Beaufort, Dimbaza and East London in the Eastern Cape Province of South Africa and their implication to the production of effluents of good quality. The samples were collected between September and December 2005 and protozoa species were identified by direct microscopic observations at x400 magnification by comparison with existing protozoa gallery collections. A total of 68 protozoan genera made up of 44 ciliates, 16 flagellates and 8 others were identified in wastewater treatment plants. Although in all aerobic zones the average density of ciliates was 104 cells mL-1, which indicated that these plants were able to produce clear effluent of good quality, a better performance was found in Dimbaza and East London, which had total protozoan genera of 27 and 26, respectively.

  14. Characterisation of raw sewage and performance assessment of primary settling tanks at Firle Sewage Treatment Works, Harare, Zimbabwe

    Science.gov (United States)

    Muserere, Simon Takawira; Hoko, Zvikomborero; Nhapi, Innocent

    The need for more stringent effluent discharge standards as prescribed by the Environmental Management Act 20:27 to protect the environment can be sustainably achieved with the aid of Activated Sludge Models. Thus, the researchers believe it is time to re-evaluate wastewater characteristics at Firle Sewage Treatment Works (STW) and make use of activated sludge simulators to address pollution challenges caused by the sewage plant. Therefore, this paper characterizes raw sewage and assesses settled and unsettled sewage in order to evaluate the performance of the primary treatment system and the suitability of the settled sewage for treatment by the subsequent Biological Nutrient Removal (BNR) system at Firle STW. Parameters studied included COD, BOD, TKN, TP, NH3, TSS, pH and Alkalinity. Composite samples were collected over a 9-day campaign period (27 June to 6 July 2012), hourly grab samples over 24 hrs and composite samples on 6 March 2012 which were then analysed in the lab in accordance with Standard Methods for the Examination of Water and Wastewater to support the City of Harare 2004-2012 lab historical records. Concentrations for unsettled sewage in mg/L were COD (527 ± 32), BOD (297 ± 83) TKN (19.0 ± 2.0), TP (18 ± 3), NH3 (24.0 ± 12.9), TSS (219 ± 57), while pH was 7.0 ± 0 and Alkalinity 266 ± 36 mg/L. For settled sewage the corresponding values in mg/L were COD (522 ± 15), BOD (324 ± 102), TKN (21.0 ± 3.0), TP (19.0 ± 2.0), NH3 (25.6 ± 11.2), TSS (250 ± 66), while pH was 7.0 ± 0 and Alkalinity 271 ± 17 mg/L. The plant design values for raw sewage are COD (650 mg/L), BOD (200 mg/L), TKN (40 mg/L) and TP (11 mg/L). Thus, COD and nitrogen were within the plant design range while BOD and TP were higher. Treatability of sewage in BNR systems is often inferred from the levels of critical parameters and also the ratios of TKN/COD and COD/TP. The wastewater average settled COD/BOD, COD/TP and TKN/COD ratio were 1.7 ± 0.5, 27.1 ± 3.1 and 0.04 ± 0

  15. Gravity settling

    Science.gov (United States)

    Davis, Hyman R.; Long, R. H.; Simone, A. A.

    1979-01-01

    Solids are separated from a liquid in a gravity settler provided with inclined solid intercepting surfaces to intercept the solid settling path to coalesce the solids and increase the settling rate. The intercepting surfaces are inverted V-shaped plates, each formed from first and second downwardly inclined upwardly curved intersecting conical sections having their apices at the vessel wall.

  16. STUDY ON APPLICATION OF AERATION BIOLOGICAL FLUID TANK TECHNOLGY IN NH+4-N WASTE WATER TREATMENT%曝气生物流化池(ABFT)技术在含氨氮污水治理的应用研究

    Institute of Scientific and Technical Information of China (English)

    陈怡; 卢建国

    2003-01-01

    This paper introduces an application of "Aeration biological fluid tank" technology (ABFT) for the treatment of waste water containing NH+4-N and high concentrated organic chemicals. Highlights were focused on the effects of dissolved oxygen, pH, temperature and retention time on waste water biological treatment in order to find out a new approach in treatment of waste water containing high concentrated NH+4-N.

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

    OpenAIRE

    Ala Sokolova; Mindaugas Rimeika

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ala Sokolova

    2011-02-01

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

  19. Effect of Aeration on Seafood Processing Wastewater

    OpenAIRE

    Neena Sunny; Jinu John

    2014-01-01

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

  20. Impact of aeration control on N2O emission in a full-scale activated sludge wastewater treatment plant

    OpenAIRE

    Filali, A.; Fayolle, Y.; Peu, P.; Philippe, L.; Nauleau, F.; Gillot, S.

    2013-01-01

    International audience This work investigated the impact of aeration control strategy on energy consumption and nitrous oxide (N2O) emission in a full-scale wastewater treatment plant. Two identical activated sludge processes treating the same effluent but operated with different aeration control strategies were compared. Aeration tank 1 was operated with a new control strategy favouring the simultaneous nitrification denitrification (SND) whereas aeration tank 2 was operated with a conven...

  1. Improving Settling Dynamics of Activated Sludge by Adding Fine Talc Powder

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Larsen, Torben; Clauss, F.

    1996-01-01

    The effect of adding varying mixtures of talc and chlorite powder to activated sludge in order to improve the settling characteristic has been studied. The powder is found to improve the settling velocity of the sludge, strictly by increasing the average density of the sludge floc aggregate. The...... settling velocity was measured with a recirculated settling column under different concentrations and turbulence levels. Numerical simulation of a secondary settling tank indicates that adding fine powder will improve the overall performance considerably....

  2. Solar powered dugout aeration

    International Nuclear Information System (INIS)

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

  3. Aerator Placement Strategies

    Science.gov (United States)

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

  4. Settled and unsettled issues in particle settling

    International Nuclear Information System (INIS)

    Colloid sedimentation has played a seminal role in the development of statistical physics thanks to the celebrated experiments by Perrin, which provided a concrete demonstration of molecular reality and gave strong support to Einstein's theory of Brownian motion. This review, which mostly focuses on settling at low Peclét number, where Brownian fluctuations are dominant, aims to show that a lot more can be learnt both from the sedimentation equilibrium and from the particle settling dynamics of a wide class of systems, ranging from simple colloids to mesogenic suspensions, from soft solids to active particles and living organisms. At the same time, the occurrence of unexpected and surprising effects brings about challenging questions in statistical and fluid mechanics that make sedimentation an exciting field of research. (review article)

  5. Effect of Aeration on Seafood Processing Wastewater

    Directory of Open Access Journals (Sweden)

    Neena Sunny

    2014-04-01

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

  6. Aeration control in a full-scale activated sludge wastewater treatment plant: impact on performances, energy consumption and N2O emission

    OpenAIRE

    Filali, A.; Fayolle, Y.; Peu, P.; Philippe, L.; Nauleau, F.; Gillot, S.

    2013-01-01

    International audience This work investigated the impact of aeration control strategy on energy consumption and nitrous oxide (N2O) emission in a full-scale wastewater treatment plant. Two identical activated sludge processes treating the same effluent but operated with different aeration control strategies were compared. Aeration tank 1 was operated with a new control strategy favouring the simultaneous nitrification denitrification (SND) whereas aeration tank 2 was operated with a conven...

  7. Nitrous oxide emissions from an intermittent aeration activated sludge system of an urban wastewater treatment plant

    OpenAIRE

    William Z. de Mello; Renato P. Ribeiro; Ariane C. Brotto; Débora C. Kligerman; Andrezza de S. Piccoli; Jaime L. M. Oliveira

    2013-01-01

    This study investigated the emission of N2O during the sequential aerated (60-min) and non-aerated (30-min) stages of an intermittent aeration cycle in an activated sludge wastewater treatment plant (WWTP). N2O emission occurred during both stages; however, emission was much higher during aeration. Air stripping is the major factor controlling transfer of N2O from the sewage to the atmosphere. The N2O emissions exclusively from the aeration tank represented 0.10% of the influent total nitroge...

  8. Aeration tank settling and real time control as a tool to improve the hydraulic capacity and treatment efficiency during wet weather: Results from 7 years' full-scale operational data

    DEFF Research Database (Denmark)

    Sharma, Anitha Kumari; Guildal, T.; Thomsen, H.A.R.;

    2013-01-01

    with RTC operation resulted in lower effluent concentrations for total phosphate (40-50%), suspended solids (30-60%) and chemical oxygen demand (30-50%), whereas no significant effect was observed on total nitrogen. Apart from the reduced effluent concentrations, the RTC resulted in economic savings in...

  9. Interaction between afternoon aeration and tilapia stocking density

    OpenAIRE

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

    2016-01-01

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

  10. Influence of the waste oil concentration in water on the efficiency of the aeration process in refinery wastewater treatment:

    OpenAIRE

    PAVLOVIĆ, Milan; Simić, Stojan N.; Stanojević, Miroslav; Ševaljević, Mirjana

    2008-01-01

    Process, aeration system and aeration method for biological treatment of wastewater with activated sludge in bio-aeration tanks are chosen based on theflow parameters, composition of the wastewater and required characteristicsof the purified water. Choosing an aeration system is a very complex question, as the capacity of oxygen introduced into the wastewater should correspond to the oxygen consumption in order to achieve the most efficient purification. This paper presents the results of exp...

  11. Case study of aeration performance under changing process conditions

    DEFF Research Database (Denmark)

    Iranpour, R.; Shao, Y.J.; Ahring, Birgitte Kiær;

    2002-01-01

    Off gas analyses of oxygen transfer efficiency (OTE) at Terminal Island Treatment Plant of Los Angeles document changing performance of fine-pore diffusers in an activated sludge plant from 1991 to 1998. Although the plant treats a challenging waste stream, the aeration tanks are little different...... from other plants. Recent sessions provided improved time and space resolution, compared to previous work. Samples were more closely spaced, and some samples were taken in the intervals between the aeration grids, at the ends of the tanks, and near the edges of the grids. Very short term fluctuations...

  12. Sludge Settling Rate Observations and Projections at the Savannah River Site - 13238

    International Nuclear Information System (INIS)

    Since 2004, sludge batches have included a high percentage of stored sludge generated from the H- modified (HM) process. The slow-settling nature of HM sludge means that the settling is often the major part of the washing tank quiescent period between required pump runs to maintain flammability control. Reasonable settling projections are needed to wash soluble salts from sludge in an efficient manner, to determine how much sludge can be washed in a batch within flammability limits, and to provide composition projections for batch qualification work done in parallel with field preparation. Challenges to providing reasonably accurate settling projections include (1) large variations in settling behavior from tank-to-tank, (2) accounting for changing initial concentrations, sludge masses, and combinations of different sludge types, (3) changing the settling behavior upon dissolving some sludge compounds, and (4) sludge preparation schedules that do not allow for much data collection for a particular sludge before washing begins. Scaling from laboratory settling tests has provided inconsistent results. Several techniques have been employed to improve settling projections and therefore the overall batch preparation efficiency. Before any observations can be made on a particular sludge mixture, projections can only be made based on historical experience with similar sludge types. However, scaling techniques can be applied to historical settling models to account for different sludge masses, concentrations, and even combinations of types of sludge. After sludge washing/settling cycles begin, the direct measurement of the sludge height, once generally limited to a single turbidity meter measurement per settle period, is now augmented by examining the temperature profile in the settling tank, to help determine the settled sludge height over time. Recently, a settling model examined at PNNL [1,2,3] has been applied to observed thermocouple and turbidity meter readings to

  13. Turbulência induzida por jatos bifásicos do tipo gás-líquido em tanques de aeração Turbulence induced by two-phase gas-liquid jets in aeration tanks

    Directory of Open Access Journals (Sweden)

    Iran Eduardo Lima Neto

    2010-03-01

    Full Text Available Jatos bifásicos do tipo gás-líquido são bastante usados nas engenharias sanitária e ambiental para fins de aeração artificial e mistura turbulenta. O presente trabalho investiga a turbulência gerada por meio desses jatos em um tanque de água, utilizando velocimetria por imagem de partículas. As condições experimentais incluíram jatos bifásicos com frações volumétricas de ar de até 70% e números de Reynolds variando entre 10.600 e 17.700. Os resultados dos ensaios indicaram que a fração volumétrica de ar afeta consideravelmente as propriedades turbulentas da fase líquida, enquanto o número de Reynolds apresenta efeito secundário. Correlações adimensionais foram então obtidas para expressar a energia cinética turbulenta e a taxa de dissipação de energia em função desses dois parâmetros. Finalmente, são apresentadas possíveis aplicações dos resultados deste trabalho.Two-phase gas-liquid jets are widely used in the sanitary and environmental engineering field for artificial aeration and turbulent mixing. The present work investigates the turbulence generated by these jets in a water tank, using particle image velocimetry. The experimental conditions included two-phase jets with gas volume fractions of up to 70% and Reynolds numbers ranging from 10,600 to 17,700. The results indicated that the gas volume fraction affects significantly the turbulent properties of the liquid phase, while the Reynolds number presents a secondary effect. Dimensionless correlations were then obtained to express the turbulent kinetic energy and dissipation rate as a function of these two parameters. Finally, possible applications of the results obtained in this work are presented.

  14. A Method for Measuring Sludge Settling Characteristics in Turbulent Flows

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Larsen, Torben

    1996-01-01

    A method for the determination of the settlilng velocity for sludge as a funktion of turbulence intensity and sludge concentration has been developed. The principle of the method is to continuously feed the top of a settling column with sludge so that a steady state and uniform concentration dist...... velocities can be measured at arbitrarily selected combinations of turbulence and concentration. The foremost advantage of the method is that settlilng characteristics measured in this way can be utilized directly in numerical models of sedimentation tanks, process tanks, etc....... a mass balance involving concentration at the top and the middle of the column as well as the inlet sludge flow. The resulting mass balance is used to calculate a lokal settling velocity. The turbulence is introduced by an oscillating grid in the whole depth of the settling column. Settling...

  15. Catfish production using intensive aeration

    Science.gov (United States)

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

  16. A new settling velocity model to describe secondary sedimentation

    DEFF Research Database (Denmark)

    Ramin, Elham; Wágner, Dorottya Sarolta; Yde, Lars;

    2014-01-01

    Secondary settling tanks (SSTs) are the most hydraulically sensitive unit operations in biological wastewater treatment plants. The maximum permissible inflow to the plant depends on the efficiency of SSTs in separating and thickening the activated sludge. The flow conditions and solids distribut......Secondary settling tanks (SSTs) are the most hydraulically sensitive unit operations in biological wastewater treatment plants. The maximum permissible inflow to the plant depends on the efficiency of SSTs in separating and thickening the activated sludge. The flow conditions and solids...

  17. Settling with the government

    Energy Technology Data Exchange (ETDEWEB)

    Macbeth, A.

    The nature of both litigation and settlement with the government is different from private litigation. In the environmental field, the growth of hazardous substances litigation, particularly under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA or Superfund), has made some real changes in this pattern. Nevertheless, the Environmental Protection Agency's (EPA) past and present litigation and settlement practices can best be understood by starting with this precept. This article discusses the problems of settling disputes with environmental agencies by focusing on the characteristics and instincts that distinguish the environmental agencies from private litigants. This is not meant to suggest that all the normal skills and talents of a negotiator are not important to reaching a settlement with the government; they are. But the environmental agencies have institutional habits and restraints that are important to understand for effective dispute resolution.

  18. Limit of stokesian settling concentration characterizes sludge settling velocity.

    Science.gov (United States)

    Mancell-Egala, William A S K; Kinnear, David J; Jones, Kimberly L; De Clippeleir, Haydée; Takács, Imre; Murthy, Sudhir N

    2016-03-01

    Flocculent settling (stokesian) is predominant within ideally operating clarifiers, and the shift to 'slower' hindered settling (non-stokesian) causes both failure and poor effluent quality. Therefore, a new metric for settling characteristics was developed and classified as Limit of Stokesian Settling (LOSS). The technique consisted of determining the total suspended solids (TSS) concentration at which mixed liquor settling characteristics transition from stokesian to non-stokesian settling. An image analytical technique was developed with the aid of MATLAB(®) to identify this transition. The MATLAB tool analyzed RGB images from video, and identified the presence of an interface by a dramatic shift in the Red indices. LOSS data for Secondary activated-sludge systems were analyzed for a period of 60 days at the Blue Plains Advanced Wastewater Treatment Plant. LOSS for secondary systems typically occurred between 600 and 700 mg TSS/L but reached 1000 mg TSS/L for a good settling secondary sludge and 500 mg TSS/L for a poor settling secondary sludge, settling quality was based on hindered settling rates. In addition, LOSS was collected for granular systems seeded with cyclone underflow from Strass Wastewater Treatment Plant, it was observed that LOSS was higher for granular systems ranging from 1600 to 5500 mg TSS/L for low and high levels of granulation, respectively. The monovalent to divalent cation ratio (M/D) was increased with the addition of sodium ions to deteriorate settling properties. Samples adjusted with higher M/D consistently had 100 mg TSS/L (15%) decrease in LOSS from the control. LOSS numbers collected experimentally were validated with the Takacs et al. (1991) settling model. When compared to flux curves with small changes in sludge matrix, LOSS was proven to be faster at characterizing hindered settling velocity and was less erratic. This is the first time a measurement method has been developed to characterize the transition from stokesian

  19. Modeling and optimization of poly(3hydroxybutyrate-co-3hydroxyvalerate) production from cane molasses by Azohydromonas lata MTCC 2311 in a stirred-tank reactor: effect of agitation and aeration regimes.

    Science.gov (United States)

    Zafar, Mohd; Kumar, Shashi; Kumar, Surendra; Dhiman, Amit K

    2012-07-01

    The effects of agitation and aeration rates on copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] production by Azohydromonas lata MTCC 2311 using cane molasses supplemented with propionic acid in a bioreactor were investigated. The experiments were conducted in a three-level factorial design by varying the impeller (150-500 rev min(-1)) and aeration (0.5-1.5 vvm) rates. Further, the data were fitted to mathematical models [quadratic polynomial equation and artificial neural network (ANN)] and process variables were optimized by genetic algorithm-coupled models. ANN and hybrid ANN-GA were found superior for modeling and optimization of process variables, respectively. The maximum copolymer concentration of 7.45 g l(-1) with 21.50 mol% of 3HV was predicted at process variables: agitation speed, 287 rev min(-1); and aeration rate, 0.85 vvm, which upon validation gave 7.20 g l(-1) of P(3HB-co-3HV) with 21 mol% of 3HV with the prediction error (%) of 3.38 and 2.32, respectively. Agitation speed established a relative high importance of 72.19% than of aeration rate (27.80%) for copolymer accumulation. The volumetric gas-liquid mass transfer coefficient (k (L) a) was strongly affected by agitation and aeration rates. The highest P(3HB-co-3HV) productivity of 0.163 g l(-1) h(-1) was achieved at 0.17 s(-1) of k (L) a value. During the early phase of copolymer production process, 3HB monomers were accumulated, which were shifted to 3HV units (9-21%) during the cultivation period of 24-42 h. The enhancement of 7.5 and 34% were reported for P(3HB-co-3HV) production and 3HV content, respectively, by hybrid ANN-GA paradigm, which revealed the significant utilization of cane molasses for improved copolymer production. PMID:22361743

  20. Microthrix parvicella abundance associates with activated sludge settling velocity and rheology - Quantifying and modelling filamentous bulking

    DEFF Research Database (Denmark)

    Wágner, Dorottya Sarolta; Ramin, Elham; Szabo, Peter;

    2015-01-01

    The objective of this work is to identify relevant settling velocity and rheology model parameters and to assess the underlying filamentous microbial community characteristics that can influence the solids mixing and transport in secondary settling tanks. Parameter values for hindered, transient...

  1. Radon removal equipment based on aeration: A literature study of tests performed in Sweden between 1981 and 1996

    Energy Technology Data Exchange (ETDEWEB)

    Mjoenes, L

    2000-02-01

    In Sweden some principles to reduce the radon concentration in drinking water were tested in the beginning of the 1980s. Spray aeration under atmospheric pressure, diffused bubble aeration, aeration in the pressure tank and different combinations of these principles were studied. Aeration in the drill hole and adsorption on granulated activated char-coal were also tested. The best results, about 70 % reduction, were obtained with aeration in the pressure tank with a spray system combined with diffused air bubbling. The Oerebro project in the beginning of the 1990s included on site testing of five different aeration solutions: Aeration in the drill hole, aeration in the storage tank, ejector aeration, shallow tray aeration and packed column aeration. The radon removal efficiency varied between 20 % and 99 %. In 1994 a study intended to test the radon removal capacity of different water treatment equipment was performed. Six units of radon separators were included but most of the tested equipment was installed for other water treatment purposes. The performed measurements showed that the only types of equipment that reduce the radon concentration efficiently are radon separators and reverse osmosis filters. The radon removal capacity of the radon separators varied between 23 % and 97 %. In 1996 the nine most common radon separators on the Swedish market were tested. The results showed that the tested radon removal equipment worked well, although the technical quality and chosen technical solutions were not always the best. The radon removal capacity of the units participating in this test was in most cases between 96 and 99 %. In some cases the capacity exceeded 99 %. In order to reach this radon removal capacity the water must be recirculated in a storage tank under atmospheric pressure.

  2. Radon removal equipment based on aeration: A literature study of tests performed in Sweden between 1981 and 1996

    International Nuclear Information System (INIS)

    In Sweden some principles to reduce the radon concentration in drinking water were tested in the beginning of the 1980s. Spray aeration under atmospheric pressure, diffused bubble aeration, aeration in the pressure tank and different combinations of these principles were studied. Aeration in the drill hole and adsorption on granulated activated char-coal were also tested. The best results, about 70 % reduction, were obtained with aeration in the pressure tank with a spray system combined with diffused air bubbling. The Oerebro project in the beginning of the 1990s included on site testing of five different aeration solutions: Aeration in the drill hole, aeration in the storage tank, ejector aeration, shallow tray aeration and packed column aeration. The radon removal efficiency varied between 20 % and 99 %. In 1994 a study intended to test the radon removal capacity of different water treatment equipment was performed. Six units of radon separators were included but most of the tested equipment was installed for other water treatment purposes. The performed measurements showed that the only types of equipment that reduce the radon concentration efficiently are radon separators and reverse osmosis filters. The radon removal capacity of the radon separators varied between 23 % and 97 %. In 1996 the nine most common radon separators on the Swedish market were tested. The results showed that the tested radon removal equipment worked well, although the technical quality and chosen technical solutions were not always the best. The radon removal capacity of the units participating in this test was in most cases between 96 and 99 %. In some cases the capacity exceeded 99 %. In order to reach this radon removal capacity the water must be recirculated in a storage tank under atmospheric pressure

  3. Nitrous oxide emissions from an intermittent aeration activated sludge system of an urban wastewater treatment plant

    Directory of Open Access Journals (Sweden)

    William Z. de Mello

    2013-01-01

    Full Text Available This study investigated the emission of N2O during the sequential aerated (60-min and non-aerated (30-min stages of an intermittent aeration cycle in an activated sludge wastewater treatment plant (WWTP. N2O emission occurred during both stages; however, emission was much higher during aeration. Air stripping is the major factor controlling transfer of N2O from the sewage to the atmosphere. The N2O emissions exclusively from the aeration tank represented 0.10% of the influent total nitrogen load and the per capita emission factor was almost 3 times higher than that suggested by the IPCC for inventories of N2O emission from WWTPs.

  4. WWTP Process Tank Modelling

    DEFF Research Database (Denmark)

    Laursen, Jesper

    solution of the Navier-Stokes equations in a multiphase scheme. After a general introduction to the activated sludge tank as a system, the activated sludge tank model is gradually setup in separate stages. The individual sub-processes that are often occurring in activated sludge tanks are initially...... investigated individually, with the purpose of obtaining a better understanding before the final integrated model is setup. In the sub-process investigations focus is addressed especially at aeration by bottom mounted diffusers and mechanical mixing of the activated sludge suspension via slowly rotating...... hydrofoil shaped propellers. These two sub-processes deliver the main part of the supplied energy to the activated sludge tank, and for this reason they are important for the mixing conditions in the tank. For other important processes occurring in the activated sludge tank, existing models and measurements...

  5. Optimization of aeration for biodiesel production by Scenedesmus obliquus grown in municipal wastewater.

    Science.gov (United States)

    Han, Song-Fang; Jin, Wenbiao; Tu, Renjie; Abomohra, Abd El-Fatah; Wang, Zhi-Han

    2016-07-01

    Despite the significant breakthroughs in research on microalgae as a feedstock for biodiesel, its production cost is still much higher than that of fossil diesel. One possible solution to overcome this problem is to optimize algal growth and lipid production in wastewater. The present study examines the optimization of pretreatment of municipal wastewater and aeration conditions in order to enhance the lipid productivity of Scenedesmus obliquus. Results showed that no significant differences were recorded in lipid productivity of S. obliquus grown in primary settled or sterilized municipal wastewater; however, ultrasound pretreatment of wastewater significantly decreased the lipid production. Whereas, aeration rates of 0.2 vvm significantly increased lipid content by 51 %, with respect to the non-aerated culture, which resulted in maximum lipid productivity (32.5 mg L(-1) day(-1)). Furthermore, aeration enrichment by 2 % CO2 resulted in increase of lipid productivity by 46 % over the CO2 non-enriched aerated culture. Fatty acid profile showed that optimized aeration significantly enhanced monounsaturated fatty acid production, composed mainly of C18:1, by 1.8 times over the non-aerated S. obliquus culture with insignificant changes in polyunsaturated fatty acid proportion; suggesting better biodiesel characteristics for the optimized culture. PMID:26969589

  6. Intermittent feeding of wastewater in combination with alternating aeration for complete denitrification and control of filaments.

    Science.gov (United States)

    Kantartzi, Styliani; Melidis, Paraschos; Aivasidis, Alexander

    2010-01-01

    In the present study, a laboratory scale system, consisting of a primary settling tank, a continuous stirred tank reactor and a clarifier were constructed and operated, using wastewater from the municipal wastewater treatment plant in Xanthi, Greece. The system operated under intermittent aeration in aerobic/anoxic conditions and feeding of the wastewater once in every cycle. The unit was inoculated with sludge, which originated from the recirculation stream of the local wastewater treatment plant. The wastewater was processed with hydraulic retention time (HRT) of 12 h, in which various experimental states were studied regarding the combination of aerobic and anoxic intervals. The wastewater was fed in limited time once in every cycle of aerobic/anoxic conditions at the beginning of the anoxic period. The two states that exhibited highest performance in nitrification and total nitrogen removal were, then, repeated with HRT of 10 h. The results show that, regarding the nitrification stage and the organic load removal, the intermittent system achieved optimum efficiency, with an overall removal of biological oxygen demand (BOD(5)) and ammonium nitrogen in the range of 93-96% and 91-95% respectively. As far as the total nitrogen removal is concerned, and if the stage of the denitrification is taken into account, the performance of the intermittent system surpassed other methods, as it is shown by the total Kjeldahl nitrogen (TKN) removal efficiency of 85-87%. These operating conditions suppressed the growth of filamentous organisms, a fact reflected at the SVI values, which were lower than 150 ml/g. PMID:20418622

  7. Flocculent Settling of Food Wastes.

    Science.gov (United States)

    Chowdhury, Mohammad Monirul Islam; Kim, Mingu; Haroun, Basem Mikhaeil; Nakhla, George; Keleman, Michael

    2016-07-01

    This study evaluated the flocculent settling in water and municipal wastewater (MWW) in a 10.6 ft deep column. A total of eight runs at three different testing conditions involving MWW alone, food waste (FW) alone, and FW in MWW (FW+MWW) were conducted. Total suspended solid (TSS), total BOD (TBOD), total COD (TCOD), total nitrogen (TN), and total phosphorous (TP) removal efficiencies after 3 hours of settling were 62%, 46%, 49%, 46% and 62% for FW, and 50%, 43%, 39%, 37% and 24% for MWW. Removal efficiencies of particulate COD (PCOD) and particulate BOD (PBOD) at the lowest surface overflow rate (SOR) of 1.1 m(3)/m(2)/hr corresponding to the longest settling time of 3 hours were 59% and 64% for FW, and 65% and 70% for FW with MWW samples. On the other hand, no significant variation between FW and FW with MWW was observed for PN removal after 3 hours of settling. PMID:27329062

  8. Aeration equipment for small depths

    Science.gov (United States)

    Sluše, Jan; Pochylý, František

    2015-05-01

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

  9. Deflector plants turbine aeration

    International Nuclear Information System (INIS)

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

  10. Settling velocities in batch sedimentation

    International Nuclear Information System (INIS)

    The sedimentation of mixtures containing one and two sizes of spherical particles (44 and 62 μm in diameter) was studied. Radioactive tracing with 57Co was used to measure the settling velocities. The ratio of the settling velocity U of uniformly sized particles to the velocity predicted to Stokes' law U0 was correlated to an expression of the form U/U0 = epsilon/sup α/, where epsilon is the liquid volume fraction and α is an empirical constant, determined experimentally to be 4.85. No effect of viscosity on the ratio U/U0 was observed as the viscosity of the liquid medium was varied from 1x10-3 to 5x10-3 Pa.s. The settling velocities of particles in a bimodal mixture were fit by the same correlation; the ratio U/U0 was independent of the concentrations of different-sized particles

  11. Improving Settling Characteristics of Pure Oxygen Activated Sludge by Stripping of Carbon Dioxide.

    Science.gov (United States)

    Kundral, Somshekhar; Mudragada, Ratnaji; Coro, Ernesto; Moncholi, Manny; Mora, Nelson; Laha, Shonali; Tansel, Berrin

    2015-06-01

    Increased microbial activity at high ambient temperatures can be problematic for secondary clarifiers and gravity concentrators due to carbon dioxide (CO2) production. Production of CO2 in gravity concentrators leads to septic conditions and poor solids separation. The CO2 production can also be corrosive for the concrete surfaces. Effectiveness of CO2 stripping to improve solids settling was investigated using the sludge volume index (SVI) as the indicator parameter. Carbon dioxide was stripped by aeration from the sludge samples. Results from the study show that aeration also increased the pH values in the mixed liquor while removing CO2 and improving sludge settling. After 10 minutes of aeration at a rate of 0.37 m3 air/m3 water/min, 90% CO2 stripping was achieved. Based on the 30 min settling tests, the SVI increased by 26±1% after CO2 stripping while the pH increased by 0.8±0.1 pH units. PMID:26459818

  12. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    WU JianHua; RUAN ShiPing

    2008-01-01

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

  13. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

  15. Who's working on fishpond aeration

    OpenAIRE

    Kibria, S.

    1991-01-01

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

  16. Aeration equipment for small depths

    Directory of Open Access Journals (Sweden)

    Sluše Jan

    2015-01-01

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

  17. Reducing aeration energy consumption in a large-scale membrane bioreactor: Process simulation and engineering application.

    Science.gov (United States)

    Sun, Jianyu; Liang, Peng; Yan, Xiaoxu; Zuo, Kuichang; Xiao, Kang; Xia, Junlin; Qiu, Yong; Wu, Qing; Wu, Shijia; Huang, Xia; Qi, Meng; Wen, Xianghua

    2016-04-15

    Reducing the energy consumption of membrane bioreactors (MBRs) is highly important for their wider application in wastewater treatment engineering. Of particular significance is reducing aeration in aerobic tanks to reduce the overall energy consumption. This study proposed an in situ ammonia-N-based feedback control strategy for aeration in aerobic tanks; this was tested via model simulation and through a large-scale (50,000 m(3)/d) engineering application. A full-scale MBR model was developed based on the activated sludge model (ASM) and was calibrated to the actual MBR. The aeration control strategy took the form of a two-step cascaded proportion-integration (PI) feedback algorithm. Algorithmic parameters were optimized via model simulation. The strategy achieved real-time adjustment of aeration amounts based on feedback from effluent quality (i.e., ammonia-N). The effectiveness of the strategy was evaluated through both the model platform and the full-scale engineering application. In the former, the aeration flow rate was reduced by 15-20%. In the engineering application, the aeration flow rate was reduced by 20%, and overall specific energy consumption correspondingly reduced by 4% to 0.45 kWh/m(3)-effluent, using the present practice of regulating the angle of guide vanes of fixed-frequency blowers. Potential energy savings are expected to be higher for MBRs with variable-frequency blowers. This study indicated that the ammonia-N-based aeration control strategy holds promise for application in full-scale MBRs. PMID:26905799

  18. Microthrix parvicella abundance associates with activated sludge settling velocity and rheology - Quantifying and modelling filamentous bulking.

    Science.gov (United States)

    Wágner, Dorottya S; Ramin, Elham; Szabo, Peter; Dechesne, Arnaud; Plósz, Benedek Gy

    2015-07-01

    The objective of this work is to identify relevant settling velocity and rheology model parameters and to assess the underlying filamentous microbial community characteristics that can influence the solids mixing and transport in secondary settling tanks. Parameter values for hindered, transient and compression settling velocity functions were estimated by carrying out biweekly batch settling tests using a novel column setup through a four-month long measurement campaign. To estimate viscosity model parameters, rheological experiments were carried out on the same sludge sample using a rotational viscometer. Quantitative fluorescence in-situ hybridisation (qFISH) analysis, targeting Microthrix parvicella and phylum Chloroflexi, was used. This study finds that M. parvicella - predominantly residing inside the microbial flocs in our samples - can significantly influence secondary settling through altering the hindered settling velocity and yield stress parameter. Strikingly, this is not the case for Chloroflexi, occurring in more than double the abundance of M. parvicella, and forming filaments primarily protruding from the flocs. The transient and compression settling parameters show a comparably high variability, and no significant association with filamentous abundance. A two-dimensional, axi-symmetrical computational fluid dynamics (CFD) model was used to assess calibration scenarios to model filamentous bulking. Our results suggest that model predictions can significantly benefit from explicitly accounting for filamentous bulking by calibrating the hindered settling velocity function. Furthermore, accounting for the transient and compression settling velocity in the computational domain is crucial to improve model accuracy when modelling filamentous bulking. However, the case-specific calibration of transient and compression settling parameters as well as yield stress is not necessary, and an average parameter set - obtained under bulking and good settling

  19. Research on the Effectiveness of Aerators

    Directory of Open Access Journals (Sweden)

    Vytenis Leonavičius

    2013-02-01

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

  20. Research on the Effectiveness of Aerators

    Directory of Open Access Journals (Sweden)

    Vytenis Leonavičius

    2012-12-01

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

  1. Estimate of Hanford Waste Rheology and Settling Behavior

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) Office of River Protection's Waste Treatment and Immobilization Plant (WTP) will process and treat radioactive waste that is stored in tanks at the Hanford Site. Piping, pumps, and mixing vessels have been selected to transport, store, and mix the high-level waste slurries in the WTP. This report addresses the analyses performed by the Rheology Working Group (RWG) and Risk Assessment Working Group composed of Pacific Northwest National Laboratory PNNL, Bechtel National Inc. (BNI), CH2M HILL, DOE Office of River Protection (ORP) and Yasuo Onishi Consulting, LLC staff on data obtained from documented Hanford waste analyses to determine a best-estimate of the rheology of the Hanford tank wastes and their settling behavior. The actual testing activities were performed and reported separately in referenced documentation. Because of this, many of the required topics below do not apply and are so noted

  2. Estimate of Hanford Waste Rheology and Settling Behavior

    Energy Technology Data Exchange (ETDEWEB)

    Poloski, Adam P.; Wells, Beric E.; Tingey, Joel M.; Mahoney, Lenna A.; Hall, Mark N.; Thomson, Scott L.; Smith, Gary Lynn; Johnson, Michael E.; Meacham, Joseph E.; Knight, Mark A.; Thien, Michael G.; Davis, Jim J.; Onishi, Yasuo

    2007-10-26

    The U.S. Department of Energy (DOE) Office of River Protection’s Waste Treatment and Immobilization Plant (WTP) will process and treat radioactive waste that is stored in tanks at the Hanford Site. Piping, pumps, and mixing vessels have been selected to transport, store, and mix the high-level waste slurries in the WTP. This report addresses the analyses performed by the Rheology Working Group (RWG) and Risk Assessment Working Group composed of Pacific Northwest National Laboratory (PNNL), Bechtel National Inc. (BNI), CH2M HILL, DOE Office of River Protection (ORP) and Yasuo Onishi Consulting, LLC staff on data obtained from documented Hanford waste analyses to determine a best-estimate of the rheology of the Hanford tank wastes and their settling behavior. The actual testing activities were performed and reported separately in referenced documentation. Because of this, many of the required topics below do not apply and are so noted.

  3. Intermittent Aeration in Biological Treatment of Wastewater

    Directory of Open Access Journals (Sweden)

    H. Doan

    2009-01-01

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

  4. COMPUTER AIDED DESIGN OF DIFFUSED AERATION SYSTEMS

    Science.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-15

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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  7. Factors governing the ability of clean-up plant to remove settling particles from contaminants: theory for stable particles

    International Nuclear Information System (INIS)

    Consideration is given to the processes by which particles are removed from fluid systems. In particular, it is noted that in tank, as opposed to loop, systems the natural process of gravitational settling competes with engineered removal systems. Calculational methods are given for estimating the relative amounts of settling and removal to clean-up plant for well-mixed fluids, unmixed fluids with horizontal or vertical flow, and turbulent diffusion with incomplete mixing. The criteria for complete mixing are discussed. (author)

  8. Laboratory testing in-tank sludge washing, summary letter report

    International Nuclear Information System (INIS)

    In-tank washing is being considered as a means of pretreating high-level radioactive waste sludges, such as neutralized current acid waste (NCAW) sludge. For this process, the contents of the tank will be allowed to settle, and the supernatant solution will be decanted and removed. A dilute sodium hydroxide/sodium nitrite wash solution will be added to the settled sludge and the tank contents will be mixed with a mixer pump system to facilitate washing of the sludge. After thorough mixing, the mixer pumps will be shut off and the solids will be allowed to re-settle. After settling, the supernatant solution will be withdrawn from the tank, and the wash cycle will be repeated several times with fresh wash solution. Core sample data of double shell tank 241-AZ-101 indicate that settling of NCAW solids may be very slow. A complicating factor is that strong thermal currents are expected to be generated from heat produced by radionuclides in the sludge layer at the bottom of the tank. Additionally, there are concerns that during the settling period (i.e., while mixing pumps and air-lift re-circulators are shut off), the radionuclides may heat the residual interstitial water in the sludge to the extent that violent steam discharges (steam bumping) could occur. Finally, there are concerns that during the washing steps sludge settling may be hindered as a result of the reduced ionic strength of the wash solution. To overcome the postulated reduced settling rates during the second and third washing steps, the use of flocculants is being considered. To address the above concerns and uncertainties associated with in-tank washing, PNL has conducted laboratory testing with simulant tank waste to investigate settling rates, steam bump potential, and the need for and use of flocculating agents

  9. ASPECTS REGARDING THE METHODS OF SOIL AERATION

    OpenAIRE

    A. UNGURAŞU; A. UNGUREANU

    2011-01-01

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

  10. HYDRAULIC RESEARCH OF AERATORS ON TUNNEL SPILLWAYS

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  11. Tank characterization data report: Tank 241-C-112

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, B.C.; Borsheim, G.L.; Jensen, L.

    1993-04-01

    Tank 241-C-112 is a Hanford Site Ferrocyanide Watch List tank that was most recently sampled in March 1992. Analyses of materials obtained from tank 241-C-112 were conducted to support the resolution of the Ferrocyanide Unreviewed Safety Question (USQ) and to support Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-10-00. Analysis of core samples obtained from tank 241-C-112 strongly indicates that the fuel concentration in the tank waste will not support a propagating exothermic reaction. It is probable that tank 241-C-112 exceeds the 1,000 g-mol inventory criteria established for the Ferrocyanide USQ; however, extensive energetic analysis of the waste has determined a maximum exothermic value of -9 cal/g dry waste. This value is substantially below any levels of concern (-75 cal/g). In addition, an investigation of potential mechanisms to generate concentration levels of radionuclides high enough to be of concern was performed. No credible mechanism was postulated that could initiate the formation of such concentration levels in the tank. Tank 241-C-112 waste is a complex material made up primarily of water and inert salts. The insoluble solids are a mixture of phosphates, sulfates, and hydroxides in combination with aluminum, calcium, iron, nickel, and uranium. Disodium nickel ferrocyanide and sodium cesium nickel ferrocyanide probably exist in the tank; however, there appears to have been significant degradation of this material since the waste was initially settled in the tank.

  12. Tank characterization data report: Tank 241-C-112

    International Nuclear Information System (INIS)

    Tank 241-C-112 is a Hanford Site Ferrocyanide Watch List tank that was most recently sampled in March 1992. Analyses of materials obtained from tank 241-C-112 were conducted to support the resolution of the Ferrocyanide Unreviewed Safety Question (USQ) and to support Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-10-00. Analysis of core samples obtained from tank 241-C-112 strongly indicates that the fuel concentration in the tank waste will not support a propagating exothermic reaction. It is probable that tank 241-C-112 exceeds the 1,000 g-mol inventory criteria established for the Ferrocyanide USQ; however, extensive energetic analysis of the waste has determined a maximum exothermic value of -9 cal/g dry waste. This value is substantially below any levels of concern (-75 cal/g). In addition, an investigation of potential mechanisms to generate concentration levels of radionuclides high enough to be of concern was performed. No credible mechanism was postulated that could initiate the formation of such concentration levels in the tank. Tank 241-C-112 waste is a complex material made up primarily of water and inert salts. The insoluble solids are a mixture of phosphates, sulfates, and hydroxides in combination with aluminum, calcium, iron, nickel, and uranium. Disodium nickel ferrocyanide and sodium cesium nickel ferrocyanide probably exist in the tank; however, there appears to have been significant degradation of this material since the waste was initially settled in the tank

  13. The settling-time reducibility ordering

    OpenAIRE

    Csima, Barbara F.; Shore, Richard A.

    2007-01-01

    To each computable enumerable (c.e.) set A with a particular enumeration {As}s∈ ω, there is associated a settling function mA(x), where mA(x) is the last stage when a number less than or equal to x was enumerated into A. One c.e. set A is settling time dominated by another set B (B>stA) if for every computable function f, for all but finitely many x, mB(x)>f(mA(x)). This settling-time ordering, which is a natural extension to an ordering of the idea of domination, was fir...

  14. Numerical and experimental investigation of the self-inducing turbine aeration capacity

    International Nuclear Information System (INIS)

    Highlights: • Numerical and experimental study of kLa coefficient of a self-inducing turbine. • Validation of experimental results. • Numerical study of kLa variation with the variation of impeller submersion and blade inclination. • Numerical study of the flow field and hydrodynamic parameters. - Abstract: Self-inducing turbines are a model of mixers that ensure the aeration of a fluid field without using a sparger and a surface aerator. Nevertheless, this type of turbines remain quite complicated in terms of behavior of the fluid within the tank, and its actual aeration capacity varies depending on the type of turbine used. The studied turbine is self-inducing and made of three blades and each blade contains five holes. In this work, we evaluated experimentally – using the technique of dynamic oxygenation and deoxygenating – the aeration capacity of our impeller by calculating the volumetric mass transfer coefficient kLa for various submergences and various inclination angles of the blade. This work was then validated by a numerical modeling using the commercial code Fluent, and the flow within the tank as well as the evolution of the hydrodynamic parameters was also studied. The simulation is steady state with a VOF multiphase model and the realizable k–ε turbulence model. We finally concluded that kLa decreases with the increase of the inclination angle and with the increase of the submergence of our turbine. We could also study the hydrodynamic parameters of the flow such as the power number, the aeration number and the shear rate

  15. DESIGN MANUAL: FINE PORE AERATION SYSTEMS

    Science.gov (United States)

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

  16. EMERGENCE ANGLE OF FLOW OVER AN AERATOR

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  17. T.A. BROWN MECHANICAL AERATOR

    Science.gov (United States)

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

  18. Aerobics trainer, health club settle discrimination lawsuit.

    Science.gov (United States)

    1995-04-01

    A health club settled out-of-court, agreeing to pay an undisclosed sum of money and to train its managers on the legal obligations of people with HIV and other disabilities, following litigation brought by an aerobics instructor at the club. The instructor filed the suit after he was forced to either disclose his HIV status to the 3,000 members or be fired. He was fired after he refused to sign a letter drafted by the club's manager. Six months later the club's president gave club employees the letter which the plaintiff argued violated his right to privacy. This is the second time a health club has settled an AIDS discrimination case. Both cases focused on the Americans with Disabilities Act (ADA). In settling the case, the club denied any wrongdoing and said they settled out of court to avoid the costs of litigation. PMID:11362274

  19. Intermittent Aeration in Biological Treatment of Wastewater

    OpenAIRE

    Doan, H.; Lohi, A.

    2009-01-01

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

  20. Yield Stress and Physical Data Results for the Tank 19F Radioactive Mound Sample and Tank 19F Simulant Samples

    International Nuclear Information System (INIS)

    The purpose of this work was to characterize and compare the settling behavior of the radioactive Tank 19F mound sample and non-radioactive Pacific Northwest Nation Laboratory simulants at 6, 11, and 16 weight percent total solids

  1. Rheology Of Settled Solids In The Small Column Ion Exchange Process

    International Nuclear Information System (INIS)

    The Small Column Ion Exchange (SCIX) process is being developed to remove cesium, strontium, and actinides from Savannah River Site (SRS) Liquid Waste using an existing waste tank (i.e., Tank 41H) to house the process. This process adds monosodium titanate (MST) to a waste tank containing salt solution (and entrained sludge solids). While the process is operating, the solid particles will begin to settle at temperatures up to 45 C. Previous testing has shown that sludge-MST slurries that sit for extended periods (i.e., 1-61 days) at elevated temperatures (i.e., 23-80 C) can develop large shear strengths which could make them difficult to resuspend and remove from the tank. The authors are conducting rheological testing of mixtures containing various concentrations of sludge, MST, and crystalline silicotitanate (CST, ground and unground) that have been aged at different times (i.e., 0 to 13 weeks) and isothermally heated to 30, 45, or 60 C. Additional tests are being conducted that will allow the solid particles to settle at 45 C for 6, 12, and 24 months. The objectives of this task are to determine the impact of settling time and temperature on the shear strength, yield stress, and consistency of the slurries and to determine the impact of radiation on slurry rheology. The testing will determine the relative impact of these parameters rather than predict the shear strength, yield stress, and consistency as a function of feed and operating conditions. This document describes the rheology of slurries containing MST and simulated sludge that sat at elevated temperatures (i.e., up to 60 C) for up to 13 weeks. Rheology of CST-containing slurries, as well as results of the long term settling (6, 12, and 24 months) and irradiation tests (10 and 100 MRad), will be reported later. The conclusions from this analysis follow: (1) MST only slurries that sat at elevated temperatures had larger shear strength, yield stress, and consistency than MST plus sludge slurries that

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

    Directory of Open Access Journals (Sweden)

    Solomin E.E

    2013-12-01

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

  3. Effects of aeration on gamma irradiation of sewage sludge

    International Nuclear Information System (INIS)

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

  4. Effects of aeration on gamma irradiation of sewage sludge

    Science.gov (United States)

    Chu, Libing; Wang, Jianlong; Wang, Bo

    2010-08-01

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

  5. Tank 241-Z-361 process and characterization history

    Energy Technology Data Exchange (ETDEWEB)

    Jones, S.A.

    1998-08-06

    An Unreviewed Safety Question (Wagoner, 1997) was declared based on lack of adequate authorization basis for Tank 241-Z-361 in the 200W Area at Hanford. This document is a summary of the history of Tank 241-Z-361 through December 1997. Documents reviewed include engineering files, laboratory notebooks from characterization efforts, waste facility process procedures, supporting documents and interviews of people`s recollections of over twenty years ago. Records of transfers into the tank, past characterization efforts, and speculation were used to estimate the current condition of Tank 241-Z-361 and its contents. Information about the overall waste system as related to the settling tank was included to help in understanding the numbering system and process relationships. The Plutonium Finishing Plant was built in 1948 and began processing plutonium in mid-1949. The Incinerator (232-Z) operated from December 1961 until May 1973. The Plutonium Reclamation Facility (PRF, 236-Z) began operation in May 1964. The Waste Treatment Facility (242-Z) operated from August 1964 until August 1976. Waste from some processes went through transfer lines to 241-Z sump tanks. High salt and organic waste under normal operation were sent to Z-9 or Z-18 cribs. Water from the retention basin may have also passed through this tank. The transfer lines to 241-Z were numbered D-4 to D-6. The 241-Z sump tanks were numbered D-4 through D-8. The D-4, 5, and 8 drains went to the D-6 sump tank. When D-6 tank was full it was transferred to D-7 tank. Prior to transfer to cribs, the D-7 tank contents was sampled. If the plutonium content was analyzed to be more than 10 g per batch, the material was (generally) reprocessed. Below the discard limit, caustic was added and the material was sent to the cribs via the 241-Z-361 settling tank where solids settled out and the liquid overflowed by gravity to the cribs. Waste liquids that passed through the 241-Z-361 settling tank flowed from PFP to ground in

  6. On-line Measurements of Settling Charateristics in Activated Sludge

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Larsen, Torben

    An on-line settling column for measuring the dynamic variations of settling velocity of activated sludge has been developed. The settling column is automatic and self-cleansing insuring continuous and reliable measurements. The settling column was tested on sludge from a batch reactor where sucrose...

  7. Sawdust discharge rate from aerated hoppers

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

  8. FLOW REGIMES BELOW AERATORS FOR DISCHARGE TUNNELS

    Institute of Scientific and Technical Information of China (English)

    MA Fei; WU Jian-hua

    2012-01-01

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

  9. PRESSURE CHARACTERISTICS OF CAVITATION CONTROL BY AERATION

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  10. Acid mine water aeration and treatment system

    Science.gov (United States)

    Ackman, Terry E.; Place, John M.

    1987-01-01

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

  11. Application of airlift bioreactor for the cultivation of aerobic oleaginous yeast Rhodotorula glutinis with different aeration rates.

    Science.gov (United States)

    Yen, Hong-Wei; Liu, Yi Xian

    2014-08-01

    The high cost of microbial oils produced from oleaginous microorganisms is the major obstacle to commercial production. In this study, the operation of an airlift bioreactor is examined for the cultivation of oleaginous yeast-Rhodotorula glutinis, due to the low process cost. The results suggest that the use of a high aeration rate could enhance cell growth. The maximum biomass concentration of 25.40 g/L was observed in the batch with a 2.0 vvm aeration rate. In addition, a higher aeration rate of 2.5 vvm could achieve the maximum growth rate of 0.46 g/L h, about twice the 0.22 g/L h obtained in an agitation tank. However, an increase in tank pressure instead of the aeration rate did not enhance cell growth. The operation of airlift bioreactor described in this work has the advantages of simple operation and low energy consumption, thus making it suitable for the accumulation of microbial oils. PMID:24503421

  12. Evaluating Feed Delivery Performance in Scaled Double-Shell Tanks

    International Nuclear Information System (INIS)

    The Hanford Tank Operations Contractor (TOC) and the Hanford Waste Treatment and Immobilization Plant (WTP) contractor are both engaged in demonstrating mixing, sampling, and transfer system capability using simulated Hanford High-Level Waste (HLW) formulations. This work represents one of the remaining technical issues with the high-level waste treatment mission at Hanford. The TOCs' ability to adequately mix and sample high-level waste feed to meet the WTP WAC Data Quality Objectives must be demonstrated. The tank mixing and feed delivery must support both TOC and WTP operations. The tank mixing method must be able to remove settled solids from the tank and provide consistent feed to the WTP to facilitate waste treatment operations. Two geometrically scaled tanks were used with a broad spectrum of tank waste simulants to demonstrate that mixing using two rotating mixer jet pumps yields consistent slurry compositions as the tank is emptied in a series of sequential batch transfers. Testing showed that the concentration of slow settling solids in each transfer batch was consistent over a wide range of tank operating conditions. Although testing demonstrated that the concentration of fast settling solids decreased by up to 25% as the tank was emptied, batch-to-batch consistency improved as mixer jet nozzle velocity in the scaled tanks increased

  13. Evaluating Feed Delivery Performance in Scaled Double-Shell Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kearn P.; Thien, Michael G.

    2013-11-07

    The Hanford Tank Operations Contractor (TOC) and the Hanford Waste Treatment and Immobilization Plant (WTP) contractor are both engaged in demonstrating mixing, sampling, and transfer system capability using simulated Hanford High-Level Waste (HLW) formulations. This work represents one of the remaining technical issues with the high-level waste treatment mission at Hanford. The TOCs' ability to adequately mix and sample high-level waste feed to meet the WTP WAC Data Quality Objectives must be demonstrated. The tank mixing and feed delivery must support both TOC and WTP operations. The tank mixing method must be able to remove settled solids from the tank and provide consistent feed to the WTP to facilitate waste treatment operations. Two geometrically scaled tanks were used with a broad spectrum of tank waste simulants to demonstrate that mixing using two rotating mixer jet pumps yields consistent slurry compositions as the tank is emptied in a series of sequential batch transfers. Testing showed that the concentration of slow settling solids in each transfer batch was consistent over a wide range of tank operating conditions. Although testing demonstrated that the concentration of fast settling solids decreased by up to 25% as the tank was emptied, batch-to-batch consistency improved as mixer jet nozzle velocity in the scaled tanks increased.

  14. Shear reinforced beams in autoclaved aerated concrete

    DEFF Research Database (Denmark)

    Cornelius, Thomas

    2010-01-01

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

  15. Soil Aeration Variability as Affected by Reoxidation

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-07-25

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

  17. Landfill aeration worldwide: Concepts, indications and findings

    International Nuclear Information System (INIS)

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

  18. The biological treatment of petroleum tank draw waters

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Jose L. [Envirosystems Supply, Inc., Hollywood, FL (United States); Stephens, Greg [Plantation Pipeline, Atlanta, GA (United States)

    1993-12-31

    This work reviews and summarizes the performance of a biological process (followed by the state-of-the-art) for the removal of organic compounds in petroleum tank draw waters. Trickling filter and the extended aeration modification of activated sludge were selected as the biological processes tested in pilot units. 4 refs., 2 figs., 3 tabs.

  19. Experimental evaluation of the oxygen transfer in bubble aeration systems. Full scale experiences in lengthened activated sludge reactors

    International Nuclear Information System (INIS)

    The results of some full-scale oxygen transfer measurements conduced at the lengthened activate sludge tanks of two WWTPs of Trentino Region, are presented and discussed. As far at the tests in clean water are concerned, the non-liner regression method seems non accurate; important conclusion on the correlation between oxygen transfer process and typical parameters (i.e., fine-bubble diffusers, specific air flux) are derived. As far as the test in the wastewater is concerned, an increase of α-value from the inlet to the end of aeration tanks has been observed in the 'Andalo' WWTP

  20. Competing jurisdictions: settling land claims in Africa

    OpenAIRE

    Evers, Sandra; Spierenburg, M.; Wels, H.

    2005-01-01

    The papers included in this volume were earlier presented at a conference on the settlement of land claims in Africa, which was held in Amsterdam in September 2003. The papers are written primarily from an anthropological perspective. Contributions: Introduction: competing jurisdictions: settling land claims in Africa, including Madagascar (Sandra Evers, Marja Spierenburg and Harry Wels); Communal tenure 'from above' and 'from below': land rights, authority and livelihoods in rural South Afri...

  1. Reduced particle settling speed in turbulence

    CERN Document Server

    Fornari, Walter; Sardina, Gaetano; Brandt, Luca

    2016-01-01

    We study the settling of finite-size rigid spheres in sustained homogeneous isotropic turbulence (HIT) using Direct Numerical Simulations. In particular, an immersed boundary method is used to account for the dispersed solid phase. We study semi-dilute suspensions of spheres at different Galileo numbers, Ga. The Galileo number is the ratio between buoyancy and viscous forces, and is here varied via the solid-to-fluid density ratio. The focus is on particles that are slightly heavier than the fluid. We find that in HIT, the mean settling speed is less than in quiescent fluid and it reduces by 6 to 60\\% with respect to the terminal velocity of an isolated sphere in quiescent fluid "Vt", as the ratio between "Vt" and the turbulent velocity fluctuations u' is decreased. Analysing the fluid-particle relative motion, we find that the mean settling speed is progressively reduced while reducing due to the increase of the vertical drag induced by the particle cross-flow velocity. Unsteady effects contribute to the mea...

  2. In-Tank Elutriation Test Report And Independent Assessment

    International Nuclear Information System (INIS)

    period of decades. 2. The radionuclides were apparently either in the form of soluble compounds, like cesium, or micrometer sized particles of actinide oxides or hydroxides. 3. After the initial tank retrieval the tank contained cobble which is not conducive to elutriation. Only after the tank contents were treated with thousands of gallons of 50 wt% caustic, were the solids converted to sand which is compatible with elutriation. Discussions between SRNL and PNNL resulted in plans to test elutriation in two phases; in Phase 1 particles would be separated by differences in settling velocity in an existing scaled tank with its associated hardware and in Phase 2 additional hardware, such as a hydrocyclone, would be added downstream to separate slow settling partciels from liquid. Phase 1 of in-tank elutriation was tested for Proof of Principle in theEngineering Development Laboratory of SRNL in a 41' diameter, 87 gallon tank. The tank had been previously used as a 1/22 scale model of Hanford Waste Tank AY-102. The objective of the testing was to determine which tank operating parameters achieved the best separation between fast- and slow-settling particles. For Phase 1 testing a simulated waste tank supernatant, slow-settling particles and fast-settling particles were loaded to the scaled tank. Because this was a Proof of Principle test, readily available solids particles were used that represented fast-settling and slow-settling particles. The tank contents were agitated using rotating mixer jet pumps (MJP) which suspended solids while liquids and solids were drawn out of the tank with a suction tube. The goal was to determine the optimum hydraulic operating conditions to achieve clean separation in which the residual solids in the tank were nearly all fast-settling particles and the solids transferred out of the tank were nearly all slow-settling particles. Tests were conducted at different pump jet velocities, suction tube diameters and suction tube elevations. Testing

  3. Radon in water aeration system operational performance

    International Nuclear Information System (INIS)

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

  4. The Settling and Compaction of Nuclear Waste Slurries

    International Nuclear Information System (INIS)

    The settling and compaction of simulated and real nuclear waste slurries were extensively studied. Experiments were carried out with simulated wastes at laboratory and large-scale sizes, and the results compared. A model of settling was derived and a method developed to correlate and scale-up settling data for different slurries and vessel sizes

  5. Design aspects and performance of a settling tube system

    NARCIS (Netherlands)

    Slot, R.E.; Geldof, H.J.

    1979-01-01

    The DUST (Delft University Settling Tube) is a settling tube system intended to analyse particle size (settling velocity) of sand ranging from 0.06 mm to 2 mm, with the sample mass varying from 0.5 g to 20 g. The main parts of the system are (see fig. 1): a. the sample introduction device (venetian

  6. The Settling and Compaction of Nuclear Waste Slurries

    Energy Technology Data Exchange (ETDEWEB)

    MACLEAN, G.T.

    1999-11-15

    The settling and compaction of simulated and real nuclear waste slurries were extensively studied. Experiments were carried out with simulated wastes at laboratory and large-scale sizes, and the results compared. A model of settling was derived and a method developed to correlate and scale-up settling data for different slurries and vessel sizes.

  7. CFD model of an aerating hydrofoil

    International Nuclear Information System (INIS)

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

  8. Aeration and hydrodynamics in submerged membrane bioreactors

    OpenAIRE

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

    2011-01-01

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

  9. Biosolids reduction by the oxic-settling-anoxic process: Impact of sludge interchange rate.

    Science.gov (United States)

    Semblante, Galilee U; Hai, Faisal I; Bustamante, Heriberto; Guevara, Nelly; Price, William E; Nghiem, Long D

    2016-06-01

    The impact of sludge interchange rate (SIR) on sludge reduction by oxic-settling-anoxic (OSA) process was investigated. The sludge yield of an OSA system (a sequencing batch reactor, SBR, integrated with external anoxic reactors) was compared to that of a control (an SBR attached to a single-pass aerobic digester). SIR (%) is the percentage by volume of sludge returned from the external reactor into the main bioreactor of the OSA, and was varied from 0% to 22%. OSA achieved greater sludge reduction when fed with unsettled sewage (sCOD=113mg/L) rather than settled sewage (sCOD=60mg/L). The SIR of 11% resulted in the highest OSA performance. At the optimum SIR, higher volatile solids destruction and nitrification/denitrification (i.e., conversion of destroyed volatile solids into inert forms) were observed in the external anoxic and intermittently aerated (i.e., aerobic/anoxic) reactors, respectively. Denitrification in the aerobic/anoxic reactor was inefficient without SIR. Effluent quality and sludge settleability of the main SBR were unaffected by SIR. PMID:26810193

  10. Cavity filling water control below aerator devices

    Institute of Scientific and Technical Information of China (English)

    钱尚拓; 吴建华; 马飞; 徐建荣; 彭育; 汪振

    2014-01-01

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

  11. Solar silicon refining; Inclusions, settling, filtration, wetting

    OpenAIRE

    Ciftja, Arjan

    2009-01-01

    The main objective of the present work is the removal of inclusions from silicon scrap and metallurgical grade silicon. To reach this goal, two various routes are investigated. First, settling of SiC particles from molten silicon followed by directional solidification is reported in this thesis. Then, removal of SiC and Si3N4 inclusions in silicon scrap by filtration with foam filters and wettabilities of silicon on graphite materials are studied.To supply the increasing needs of the photovol...

  12. POTENTIAL IMPACT OF BLENDING RESIDUAL SOLIDS FROM TANKS 18/19 MOUNDS WITH TANK 7 OPERATIONS

    International Nuclear Information System (INIS)

    High level waste tanks 18F and 19F have residual mounds of waste which may require removal before the tanks can be closed. Conventional slurry pump technology, previously used for waste removal and tank cleaning, has been incapable of removing theses mounds from tanks 18F and 19F. A mechanical cleaning method has been identified that is potentially capable of removing and transferring the mound material to tank 7F for incorporation in a sludge batch for eventual disposal in high level waste glass by the Defense Waste Processing Facility. The Savannah River National Laboratory has been requested to evaluate whether the material transferred from tanks 18F/19F by the mechanical cleaning technology can later be suspended in Tank 7F by conventional slurry pumps after mixing with high level waste sludge. The proposed mechanical cleaning process for removing the waste mounds from tanks 18 and 19 may utilize a high pressure water jet-eductor that creates a vacuum to mobilize solids. The high pressure jet is also used to transport the suspended solids. The jet-eductor system will be mounted on a mechanical crawler for movement around the bottom of tanks 18 and 19. Based on physical chemical property testing of the jet-eductor system processed IE-95 zeolite and size-reduced IE-95 zeolite, the following conclusions were made: (1) The jet-eductor system processed zeolite has a mean and median particle size (volume basis) of 115.4 and 43.3 microns in water. Preferential settling of these large particles is likely. (2) The jet-eductor system processed zeolite rapidly generates settled solid yield stresses in excess of 11,000 Pascals in caustic supernates and will not be easily retrieved from Tank 7 with the existing slurry pump technology. (3) Settled size-reduced IE-95 zeolite (less than 38 microns) in caustic supernate does not generate yield stresses in excess of 600 Pascals in less than 30 days. (4) Preferential settling of size-reduced zeolite is a function of the amount of

  13. Inverse problem of bottom slope design for aerator devices

    Institute of Scientific and Technical Information of China (English)

    吴建华; 樊博; 许唯临

    2013-01-01

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

  14. Variability of Energy Dissipation and Shear Rate with Geometry in Unbaffled Surface Aerator

    Directory of Open Access Journals (Sweden)

    Bimlesh Kumar

    2009-12-01

    Full Text Available mixing in surface aerators. At constant dynamic variables (rotational speed, both  and γ are greatly affected by the geometric parameters (impeller diameter, cross-sectional area of the tank, liquid height, rotor blade length and immersion height. By doing numerical computation by VISIMIX ®, present work analyzes the effect of non-dimensional (which is non-dimensionalized through rotor diameter geometric parameters on e and g. With an increase in liquid height, there is an increase in the case of energy dissipation and shear rate values. In the case of tank area and blade length, it is vice versa. Energy dissipation and shear rate are not affected by the variation in immersion height of the impeller. © 2009 BCREC UNDIP. All rights reserved[Received: 17 October 2009, Revised: 12 December 2009, Accepted: 20 December 2009][How to Cite: B. Kumar. (2009. Variability of Energy Dissipation and Shear Rate with Geometry in Unbaffled Surface Aerator. Bulletin of Chemical Reaction Engineering and Catalysis, 4(2: 55-60. doi:10.9767/bcrec.4.2.30.55-60][How to Link/ DOI: http://dx.doi.org/10.9767/bcrec.4.2.30.55-60

  15. Variability of Energy Dissipation and Shear Rate with Geometry in Unbaffled Surface Aerator

    Directory of Open Access Journals (Sweden)

    Bimlesh Kumar

    2009-12-01

    Full Text Available mixing in surface aerators. At constant dynamic variables (rotational speed, both  and γ are greatly affected by the geometric parameters (impeller diameter, cross-sectional area of the tank, liquid height, rotor blade length and immersion height. By doing numerical computation by VISIMIX ®, present work analyzes the effect of non-dimensional (which is non-dimensionalized through rotor diameter geometric parameters on e and g. With an increase in liquid height, there is an increase in the case of energy dissipation and shear rate values. In the case of tank area and blade length, it is vice versa. Energy dissipation and shear rate are not affected by the variation in immersion height of the impeller. © 2009 BCREC UNDIP. All rights reserved[Received: 17 October 2009, Revised: 12 December 2009, Accepted: 20 December 2009][How to Cite: B. Kumar. (2009. Variability of Energy Dissipation and Shear Rate with Geometry in Unbaffled Surface Aerator. Bulletin of Chemical Reaction Engineering and Catalysis, 4(2: 55-60. doi:10.9767/bcrec.4.2.7110.55-60][How to Link/ DOI: http://dx.doi.org/10.9767/bcrec.4.2.7110.55-60 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/7110

  16. Computer modeling of forced mixing in waste storage tanks

    International Nuclear Information System (INIS)

    Numerical simulation results of fluid dynamic and physical processes in radioactive waste storage tanks are presented. Investigations include simulation of jet mixing pump induced flows intended to mix and maintain particulate material uniformly distributed throughout the liquid volume. Physical effects of solids are included in the code. These are particle size through a settling velocity and mixture properties through density and viscosity. Calculations have been accomplished for a centrally located, rotationally-oscillating, horizontally-directed jet mixing pump for two cases. One case is with low jet velocity and high settling velocity. It results in nonuniform distribution. The other case is with high jet velocity and low settling velocity. It results in uniform conditions. Results are being used to aid in experiment design and to understand mixing in the waste tanks. These results are to be used in conjunction with scaled experiments to define limits of pump operation to maintain uniformity of the mixture in the storage tanks during waste retrieval operations

  17. Tank design

    International Nuclear Information System (INIS)

    This paper reports that aboveground tanks can be designed with innovative changes to complement the environment. Tanks can be constructed to eliminate the vapor and odor emanating from their contents. Aboveground tanks are sometimes considered eyesores, and in some areas the landscaping has to be improved before they are tolerated. A more universal concern, however, is the vapor or odor that emanates from the tanks as a result of the materials being sorted. The assertive posture some segments of the public now take may eventually force legislatures to classify certain vapors as hazardous pollutants or simply health risks. In any case, responsibility will be leveled at the corporation and subsequent remedy could increase cost beyond preventive measures. The new approach to design and construction of aboveground tanks will forestall any panic which might be induced or perceived by environmentalists. Recently, actions by local authorities and complaining residents were sufficient to cause a corporation to curtail odorous emissions through a change in tank design. The tank design change eliminated the odor from fuel oil vapor thus removing the threat to the environment that the residents perceived. The design includes reinforcement to the tank structure and the addition of an adsorption section. This section allows the tanks to function without any limitation and their contents do not foul the environment. The vapor and odor control was completed successfully on 6,000,000 gallon capacity tanks

  18. 池塘微孔曝气和叶轮式增氧机的增氧性能比较%Comparison of oxygen-enriched performances of micropore and impeller aerators in pond

    Institute of Scientific and Technical Information of China (English)

    谷坚; 徐皓; 丁建乐; 车轩; 顾兆俊

    2013-01-01

    In high stocking density closed pond aquaculture, the farmed fish will suffer death from suffocation if no additional oxygen is supplied. Currently, there are various kinds of aeration methods in China, mainly including the types of impeller, water wheel, jet, propeller, and micropore aerator. The micropore aeration as the main form of bottom aeration method has been becoming one of the main aeration methods applied and expanded in China pond aquaculture in recent years. This study aimed at a systematic comparative analysis on the aeration effect and practical usage between a micropore aerator and an impeller aerator that has the best comprehensive performance and currently holds the dominant position in mechanical aeration in China, through a clean water test and a fishpond experiment. In order to study the oxygen-enriched performance of a micropore aerator and an impeller aerator in pond fish culture, we conducted the clean water oxygen-enriched performance test with the same power (2.2 kW) micropore aerator and an impeller aerator in the standard tank with a diameter of 10 meters according to the requirements described in the fisheries industry standard-“SC/T 6009-1999, the test method of oxygen-enriched capacity for aerator.”According to the experiment requirements, the tap water which was kept for a period was deoxidized using sodium sulfite (Na2SO3), and then was aerated again, while the time-variable data of dissolved oxygen (DO) concentration were measured and recorded. The oxygen-enriched capacity (Qs) and power efficiency (Es) were calculated for the impeller aerator and the micropore aerator with the obtained experiment data. The comparative experiments of actual oxygen-enriched performance and pond dissolved oxygen values variation for both aerators were conducted in a fishpond. One micropore aerator (combined with a 2.2 kW blower, 8 35-metre-long pipes were arranged in parallel with 10-meter intervals at the bottom of fish pond, the total pipe

  19. An Approach to Understanding Cohesive Slurry Settling, Mobilization, and Hydrogen Gas Retention in Pulsed Jet Mixed Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Gauglitz, Phillip A.; Wells, Beric E.; Fort, James A.; Meyer, Perry A.

    2009-05-22

    The Hanford Waste Treatment and Immobilization Plant (WTP) is being designed and built to pretreat and vitrify a large portion of the waste in Hanford’s 177 underground waste storage tanks. Numerous process vessels will hold waste at various stages in the WTP. Some of these vessels have mixing-system requirements to maintain conditions where the accumulation of hydrogen gas stays below acceptable limits, and the mixing within the vessels is sufficient to release hydrogen gas under normal conditions and during off-normal events. Some of the WTP process streams are slurries of solid particles suspended in Newtonian fluids that behave as non-Newtonian slurries, such as Bingham yield-stress fluids. When these slurries are contained in the process vessels, the particles can settle and become progressively more concentrated toward the bottom of the vessels, depending on the effectiveness of the mixing system. One limiting behavior is a settled layer beneath a particle-free liquid layer. The settled layer, or any region with sufficiently high solids concentration, will exhibit non-Newtonian rheology where it is possible for the settled slurry to behave as a soft solid with a yield stress. In this report, these slurries are described as settling cohesive slurries.

  20. Group Settling Velocity of Non-Cohesive Sediment Mixtures

    Institute of Scientific and Technical Information of China (English)

    WU Hualin; SHEN Huanting; ZHU Jianrong; ZHANG Xiaofeng

    2000-01-01

    Settling velocity is a fundamental parameter in sediment transport dynamics. For uniform par-ticles, there are abundant formulas for calculation of their settling velocities. But in natural fields, sediment consists of non-uniform particles. The interaction among particles is complex and should not be neglected. In this paper, based on the analysis of settling mechanism of non-cohesive and non-uniform particles, a theoretical model to describe settling mechanism is proposed. Besides suspension concentration andupward turbulent flow caused by other particles, collision among particles is another main factor influencing settling velocity. By introducing the collision theory, equations of fall velocity before collision, collision probability, and fall velocity after collision are established. Finally, a formula used to calculate the settling velocity of non-cohesive particles with wide grain gradation is presented, which agrees well with the experimental data.

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

    Science.gov (United States)

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

    2006-05-01

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

  2. Tank 241-C-112 vapor sampling and analysis tank characterization report

    International Nuclear Information System (INIS)

    Tank C-112 headspace gas and vapor samples were collected and analyzed to help determine the potential risks to tank farm workers due to fugitive emissions from the tank. Tank C-112 is a single-shell tank which received first-cycle decontamination waste from B Plant and was later used as a settling tank. Samples were collected from Tank C-112 using the vapor sampling system (VSS) on August 11, 1994 by WHC Sampling and Mobile Laboratories. The tank headspace temperature was determined to be 28 C. Air from the Tank C-112 headspace was withdrawn via a 7.9 m-long heated sampling probe mounted in riser 4, and transferred via heated tubing to the VSS sampling manifold. All heated zones of the VSS were maintained at approximately 50 C. Sampling media were prepared and analyzed by WHC, Oak Ridge National Laboratories, Pacific Northwest Laboratories, and Oregon Graduate Institute of Science and Technology through a contract with Sandia National Laboratories. The 39 tank air samples and 2 ambient air control samples collected are listed in Table X-1 by analytical laboratory. Table X-1 also lists the 14 trip blanks and 2 field blanks provided by the laboratories

  3. Oxidation of magnetite in aerated aqueous media

    International Nuclear Information System (INIS)

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

  4. HYDRODYNAMICS INfluence on oxidative capacity of AERATION BASIN

    OpenAIRE

    Kulkov Viktor Nikolaevich; Solopanov Evgenij Jurjevich

    2012-01-01

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

  5. Composting paper mill deinking sludge with forced aeration

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

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

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

    Science.gov (United States)

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

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

    International Nuclear Information System (INIS)

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiangju; LUO Lin; ZHAO Wenqian; LI Ran

    2004-01-01

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

  10. Investigation of abandoned surface settling ponds

    International Nuclear Information System (INIS)

    One of the problems that may appear during the ground reclamation of surface settling ponds of underground mines is enhanced radon exhalation from bottom sediments. This problem becomes more important when the concentration of radium isotopes in sediments is enhanced due to the discharge of radium-bearing waters into the pond. For investigations, special radon accumulation chambers have been designed and constructed. The concentration of radon in these chambers can be measured with the application of Lucas cells or activated charcoal detectors. In the latter method, radon is extracted from charcoal into a liquid scintillator and the sample is measured in a liquid scintillation spectrometer. Therefore the lower limit of detection (LLD) of the second method is as low as 0.1 mBq·m-2s-1, while the LLD for Lucas cells is 1.5 mBq·m-2s-1. The above-mentioned methods for the measurement of radon exhalation have been applied to investigations of a surface settling pond of one Polish coal mine, abandoned and emptied at the beginning of 2002. An agreement between the mine management and the local authority was to make the ground reclamation of the pond. A thick layer of sediments with an enhanced concentration of radium isotopes covers the bottom of the pond. The maximum concentration of radium isotopes in these sediments is as high as 2000 Bq/kg for 226Ra and up to 4000 Bq/kg for 228Ra. Two years after the complete release of brines from the pond, bottom sediments are still soaked with water. Therefore, measurements of radon in soil gas were not possible. On the other hand, in some parts of the pond investigations of radon exhalation coefficient were done. The preliminary results of measurements, conducted in 2002, showed that radon exhalation rates in specific parts of the pond were higher than the highest values of radon exhalation from the ground in the Upper Silesia region. Values of exhalation coefficient up to 200 mBq·m-2s-1 were found. It must be pointed out that

  11. Fluid interaction with spinning toroidal tanks

    Science.gov (United States)

    Fester, D. A.; Anderson, J. E.

    1977-01-01

    An experimental study was conducted to evaluate propellant behavior in spinning torroidal tanks that could be used in a retropropulsion system of an advanced outer-planet Pioneer orbiter. Information on propellant slosh and settling and on ullage orientation and stability was obtained. The effects of axial acceleration, spin rate, spin-rate change, and spacecraft wobble, both singly and in combination, were evaluated using a one-eighth scale transparent tank in one-g and low-g environments. Liquid loadings ranged from 5% to 96% full. The impact of a surface tension acquisition device was assessed by comparison with bare-tank results. The testing simulated the behavior of the fluorine/hydrazine and nitrogen textroxide/monomethylhydrazine propellants. Results are presented that indicate that no major fluid behavior problems would be encountered with any of the four propellants in the toroidal tanks of a spin-stabilized orbiter spacecraft.

  12. Parameter Calculation Technique for the Waste Treatment Facilities Using Naturally-Aerated Blocks in the Bog Ecosystems

    International Nuclear Information System (INIS)

    Technique for the domestic wastewater treatment in the small residential areas and oil and gas facilities of the natural and man-made systems including a settling tank for mechanical treatment and a biological pond with peat substrate and bog vegetation for biological treatment has been substantiated. Technique for parameters calculation of the similar natural and man-made systems has been developed. It was proven that effective treatment of wastewater can be performed in Siberia all year round

  13. Parameter Calculation Technique for the Waste Treatment Facilities Using Naturally-Aerated Blocks in the Bog Ecosystems

    Science.gov (United States)

    Akhmed-Ogly, K. V.; Savichev, O. G.; Tokarenko, O. G.; Pasechnik, E. Yu; Reshetko, M. V.; Nalivajko, N. G.; Vlasova, M. V.

    2014-08-01

    Technique for the domestic wastewater treatment in the small residential areas and oil and gas facilities of the natural and man-made systems including a settling tank for mechanical treatment and a biological pond with peat substrate and bog vegetation for biological treatment has been substantiated. Technique for parameters calculation of the similar natural and man-made systems has been developed. It was proven that effective treatment of wastewater can be performed in Siberia all year round.

  14. Bulking sludge for PHA production: Energy saving and comparative storage capacity with well-settled sludge

    Institute of Scientific and Technical Information of China (English)

    Qinxue Wen; Zhiqiang Chen; Changyong Wang; Nanqi Ren

    2012-01-01

    Two acetate-fed sequencing batch reactors (SBR) were operated under an aerobic dynamic feeding (ADF) model (SBR#2) and with anaerobic phase before aerobic phase (SBR#1) to select mixed cultures with a high polyhydroxyalkanoates (PHA) storage response.Although kinetic selection based on storage response should bring about a predominance of floc-formers,a bulking sludge with storage response comparable to well-settled sludge was steadily established.An anaerobic phase was introduced before the aerobic phase in the ADF model to improve the sludge settleability (SBR #1),however,due to the consequent increased feast/famine ratio,the performance of SBR #1,in terms of both the maximum PHB (polyhydroxybutyrate) cell content and △PHB,was lower than that of SBR #2.SBR #2 gradually reached a steady state while SBR #1 failed suddenly after 50 days of operation.The maximum specific substrate uptake rate and storage rate for the selected bulking sludge were 0.4 Cmol Ac/(Cmol X.hr) and 0.18 Cmol Ac/(Cmol PHB.hr),respectively,resulting a yield of 0.45 Cmol PHB/(Cmol Ac) in SBR #2 in the culture enrichment phase.A maximum PHB content of 53% of total suspended solids and PHB storage rate of 1.36 Cmol Ac/(Cmol PHB.hr) was achieved at 10.2 hr in batch accumulation tests under nitrogen starvation.The results indicated that it was feasible to utilize filamentous bacteria to accumulate PHA with a rate comparable to well-settled sludge.Furthermore,the lower dissolved oxygen demand of filamentous bacteria would save energy required for aeration in the culture enrichment stage.

  15. In-Tank Elutriation Test Report And Independent Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Burns, H. H.; Adamson, D. J.; Qureshi, Z. H.; Steeper, T. J.

    2011-04-13

    grown in size over a period of decades. 2. The radionuclides were apparently either in the form of soluble compounds, like cesium, or micrometer sized particles of actinide oxides or hydroxides. 3. After the initial tank retrieval the tank contained cobble which is not conducive to elutriation. Only after the tank contents were treated with thousands of gallons of 50 wt% caustic, were the solids converted to sand which is compatible with elutriation. Discussions between SRNL and PNNL resulted in plans to test elutriation in two phases; in Phase 1 particles would be separated by differences in settling velocity in an existing scaled tank with its associated hardware and in Phase 2 additional hardware, such as a hydrocyclone, would be added downstream to separate slow settling partciels from liquid. Phase 1 of in-tank elutriation was tested for Proof of Principle in theEngineering Development Laboratory of SRNL in a 41" diameter, 87 gallon tank. The tank had been previously used as a 1/22 scale model of Hanford Waste Tank AY-102. The objective of the testing was to determine which tank operating parameters achieved the best separation between fast- and slow-settling particles. For Phase 1 testing a simulated waste tank supernatant, slow-settling particles and fast-settling particles were loaded to the scaled tank. Because this was a Proof of Principle test, readily available solids particles were used that represented fast-settling and slow-settling particles. The tank contents were agitated using rotating mixer jet pumps (MJP) which suspended solids while liquids and solids were drawn out of the tank with a suction tube. The goal was to determine the optimum hydraulic operating conditions to achieve clean separation in which the residual solids in the tank were nearly all fast-settling particles and the solids transferred out of the tank were nearly all slow-settling particles. Tests were conducted at different pump jet velocities, suction tube diameters and suction tube

  16. Nitrogen tank

    CERN Multimedia

    2006-01-01

    Wanted The technical file about the pressure vessel RP-270 It concerns the Nitrogen tank, 60m3, 22 bars, built in 1979, and installed at Point-2 for the former L3 experiment. If you are in possession of this file, or have any files about an equivalent tank (probably between registered No. RP-260 and -272), please contact Marc Tavlet, the ALICE Glimos.

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

    OpenAIRE

    Ala Sokolova

    2011-01-01

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

  18. Significance of settling model structures and parameter subsets in modelling WWTPs under wet-weather flow and filamentous bulking conditions.

    Science.gov (United States)

    Ramin, Elham; Sin, Gürkan; Mikkelsen, Peter Steen; Plósz, Benedek Gy

    2014-10-15

    Current research focuses on predicting and mitigating the impacts of high hydraulic loadings on centralized wastewater treatment plants (WWTPs) under wet-weather conditions. The maximum permissible inflow to WWTPs depends not only on the settleability of activated sludge in secondary settling tanks (SSTs) but also on the hydraulic behaviour of SSTs. The present study investigates the impacts of ideal and non-ideal flow (dry and wet weather) and settling (good settling and bulking) boundary conditions on the sensitivity of WWTP model outputs to uncertainties intrinsic to the one-dimensional (1-D) SST model structures and parameters. We identify the critical sources of uncertainty in WWTP models through global sensitivity analysis (GSA) using the Benchmark simulation model No. 1 in combination with first- and second-order 1-D SST models. The results obtained illustrate that the contribution of settling parameters to the total variance of the key WWTP process outputs significantly depends on the influent flow and settling conditions. The magnitude of the impact is found to vary, depending on which type of 1-D SST model is used. Therefore, we identify and recommend potential parameter subsets for WWTP model calibration, and propose optimal choice of 1-D SST models under different flow and settling boundary conditions. Additionally, the hydraulic parameters in the second-order SST model are found significant under dynamic wet-weather flow conditions. These results highlight the importance of developing a more mechanistic based flow-dependent hydraulic sub-model in second-order 1-D SST models in the future. PMID:25003213

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

    Science.gov (United States)

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

  20. Retainment of the antimicrobial agent triclosan in a septic tank

    DEFF Research Database (Denmark)

    Kirjanova, Ala; Rimeika, Mindaugas; Vollertsen, Jes; Nielsen, Asbjørn Haaning

    2014-01-01

    Laboratory experiments were conducted to investigate the fate of the antimicrobial agent triclosan (TCS) in a conventional septic tank. The main mechanism of TCS removal from wastewater was identified to be rapid TCS sorption to suspended particles followed by settling of these particles to the...

  1. Crystal accumulation in the Hanford Waste Treatment Plant high level waste melter. Preliminary settling and resuspension testing

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fowley, M. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Miller, D. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-01

    The full scale, room temperature Hanford Tank Waste Treatment and Immobilization Plant (WTP) High-Level Waste (HLW) melter riser test system was successfully operated with silicone oil and magnetite particles at a loading of 0.1 vol %. Design and construction of the system and instrumentation, and the selection and preparation of simulant materials, are briefly reviewed. Three experiments were completed. A prototypic pour rate was maintained, based on the volumetric flow rate. Settling and accumulation of magnetite particles were observed at the bottom of the riser and along the bottom of the throat after each experiment. The height of the accumulated layer at the bottom of the riser, after the first pouring experiment, approximated the expected level given the solids loading of 0.1 vol %. More detailed observations of particle resuspension and settling were made during and after the third pouring experiment. The accumulated layer of particles at the bottom of the riser appeared to be unaffected after a pouring cycle of approximately 15 minutes at the prototypic flow rate. The accumulated layer of particles along the bottom of the throat was somewhat reduced after the same pouring cycle. Review of the time-lapse recording showed that some of the settling particles flow from the riser into the throat. This may result in a thicker than expected settled layer in the throat.

  2. Comparison of Energy Dissipation with and without Aerators

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

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

    Science.gov (United States)

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

  4. Rheology and TIC/TOC results of ORNL tank samples

    Energy Technology Data Exchange (ETDEWEB)

    Pareizs, J. M.; Hansen, E. K.

    2013-04-26

    The Savannah River National Laboratory (SRNL)) was requested by Oak Ridge National Laboratory (ORNL) to perform total inorganic carbon (TIC), total organic carbon (TOC), and rheological measurements for several Oak Ridge tank samples. As received slurry samples were diluted and submitted to SRNL-Analytical for TIC and TOC analyses. Settled solids yield stress (also known as settled shear strength) of the as received settled sludge samples were determined using the vane method and these measurements were obtained 24 hours after the samples were allowed to settled undisturbed. Rheological or flow properties (Bingham Plastic viscosity and Bingham Plastic yield stress) were determined from flow curves of the homogenized or well mixed samples. Other targeted total suspended solids (TSS) concentrations samples were also analyzed for flow properties and these samples were obtained by diluting the as-received sample with de-ionized (DI) water.

  5. Generating CO2-credits through landfill in situ aeration

    International Nuclear Information System (INIS)

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

  6. CAVITATION CONTROL BY AERATION AND ITS COMPRESSIBLE CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-yong; SU Pei-lan

    2006-01-01

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

  7. Effect of aeration on fast gas pressure tests

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  8. Experimental characterization of jet forces on waste tank components

    International Nuclear Information System (INIS)

    This paper reports that scaled experiment were performed to characterize the forces of fluid jets impacting waste tank components. The fluid jets will be produced by mixer pumps used to resuspend settled solids in million-gallon buried waste tanks on the Hanford site. Components were modeled at 1.6-scale. Forces on the full-scale tank components are predicted based on experimental data and theoretical scaling relationships. Drag coefficients, determined for the radiation dry well and air lift circulator, were used to develop relationships between fluid jet parameters and the impact forces on these two components

  9. Monitoring and troubleshooting of non-filamentous settling and dewatering problems in an industrial activated sludge treatment plant

    DEFF Research Database (Denmark)

    Kjellerup, B. V.; Keiding, Kristian; Nielsen, Per Halkjær

    2001-01-01

    A large industrial activated sludge wastewater treatment plant had temporary problems with settling and dewatering of the sludge. Microscopical investigations revealed that the poor settling properties were not due to presence of filamentous bacteria, but poor floc properties. In order to...... had started after summer closedown. Possible reasons for the changes in floc properties in the process tanks were found by a) analysing change in wastewater composition by evaluating the different production lines in the industrial plant, b) evaluating the operation of the plant, and c) performing...... at this industrial plant. The described strategy can be useful in general to find and solve many solid/liquid separation problems in activated sludge wastewater treatment plants....

  10. Winery Wastewater Treatment Applying Aerated Submerged

    Directory of Open Access Journals (Sweden)

    Alessandra Pellizzaro Bento

    2010-06-01

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

  11. Settling of almost neutrally buoyant particles in homogeneous isotropic turbulence

    Science.gov (United States)

    van Hinsberg, Michel; Clercx, Herman; Toschi, Federico

    2015-11-01

    Settling of particles in a turbulent flow occurs in various industrial and natural phenomena, examples are clouds and waste water treatment. It is well known that turbulence can enhance the settling velocity of particles. Many studies have been done, numerically and experimentally to investigate this behavior for the case of ``heavy'' particles, with particle to fluid density ratios above 100. Here we investigate the case of almost neutrally buoyant particles, i.e. density ratios between 1 and 100. In the case of light particles the Maxey-Riley equations cannot be simplified to only the Stokes drag and gravity force as pressure gradient, added mass and Basset history force are important as well. We investigate the influence of these forces on the settling velocity of particles and show that the extra forces can both increase or decrease the settling velocity, depending on the combination of the Stokes number and gravity applied.

  12. A Case of Language Revitalisation in "Settled" Australia.

    Science.gov (United States)

    Walsh, Michael

    2001-01-01

    Presents a case of language revitalisation in "settled" Australia, considers the nature of the language ecology in indigenous Australia, and advances some of the reasons for the success of this case of language revitalization. (Author/VWL)

  13. Postconstruction report for the mercury tanks interim action at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Three underground concrete settling tanks (tanks 2101-U, 2104-U, and 2100-U) at the Y-12 Plant on the Oak Ridge Reservation in Oak Ridge, Tennessee, contained contaminated sludges contributing mercury to the Upper East Fork Poplar Creek (UEFPC). These tanks were cleaned out as an interim action under the Comprehensive Environmental Response, Compensation, and Liability Act as part of the Reduction of Mercury in Plant Effluent subproject. Cleaning out these tanks prevented the sludge that had settled in the bottom from resuspending and carrying mercury into UEFPC. Tanks 2104-U and 2100-U were returned to service and will continue to receive effluent from buildings 9201-4 and 9201-5. Tank 2101-U had been abandoned and its effluent redirected to Tank 2100-U during previous activities. This interim action permanently sealed Tank 2101-U from the storm sewer system. Upon removal of materials and completion of cleanup, inspections determined that the project's cleanup criteria had been met. The structural integrity of the tanks was also inspected, and minor cracks identified in tanks 2101-U and 2104-U were repaired. This project is considered to have been completed successfully because it met its performance objectives as addressed in the Interim Record of Decision and the work plan: to remove the waste from the three storage tanks; to ensure that the tanks were cleaned to the levels specified; to return tanks 2100-U and 2104-U to service; to isolate Tank 2101-U permanently; and to manage the wastes in an appropriate fashion

  14. THE MILLER OPERATIONAL AMPLIFIER’S SETTLING RESPONSE

    Directory of Open Access Journals (Sweden)

    E. Ruíz-May

    2007-08-01

    Full Text Available This paper presents a third-order transfer function to model the settling response of the Miller operationalamplifier. The amplifier was simulated (spice and designed according to design rules of a standard 1.5μmCMOS fabrication process. The proposed mathematical model -based on design parameters under thedesigner’s control- is the best settling approach reported up to now

  15. An Analysis of Nanoparticle Settling Times in Liquids

    OpenAIRE

    Liyanage, D. D.; Rajika J. K. A. Thamali; Kumbalatara, A. A. K; Weliwita, J A; Witharana, S

    2016-01-01

    Aggregation and settling are crucial phenomena that involve particulate systems. For particle sizes of millimetre and above, there are reasonable accurate predicting tools. However for smaller particle sizes, there appears to be a void in knowledge. This paper presents an analytical model to predict the settling rates of nano-to-micro size particulate systems. The model was developed as a combination of modified classical equations and graphical methods. A calculation sequence also is present...

  16. Assessment of performing an MST strike in Tank 21H

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, Michael R.

    2014-09-29

    Previous Savannah River National Laboratory (SRNL) tank mixing studies performed for the Small Column Ion Exchange (SCIX) project have shown that 3 Submersible Mixer Pumps (SMPs) installed in Tank 41 are sufficient to support actinide removal by MST sorption as well as subsequent resuspension and removal of settled solids. Savannah River Remediation (SRR) is pursuing MST addition into Tank 21 as part of the Large Tank Strike (LTS) project. The preliminary scope for LTS involves the use of three standard slurry pumps (installed in N, SE, and SW risers) in a Type IV tank. Due to the differences in tank size, internal interferences, and pump design, a separate mixing evaluation is required to determine if the proposed configuration will allow for MST suspension and strontium and actinide sorption. The author performed the analysis by reviewing drawings for Tank 21 [W231023] and determining the required cleaning radius or zone of influence for the pumps. This requirement was compared with previous pilot-scale MST suspension data collected for SCIX that determined the cleaning radius, or zone of influence, as a function of pump operating parameters. The author also reviewed a previous Tank 50 mixing analysis that examined the ability of standard slurry pumps to suspend sludge particles. Based on a review of the pilot-scale SCIX mixing tests and Tank 50 pump operating experience, three standard slurry pumps should be able to suspend sludge and MST to effectively sorb strontium and actinides onto the MST. Using the SCIX data requires an assumption about the impact of cooling coils on slurry pump mixing. The basis for this assumption is described in this report. Using the Tank 50 operating experience shows three standard slurry pumps should be able to suspend solids if the shear strength of the settled solids is less than 160 Pa. Because Tank 21 does not contain cooling coils, the shear strength could be larger.

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

    Science.gov (United States)

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

    2015-12-01

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

  18. Aggregation and settling in aqueous polydisperse alumina nanoparticle suspensions

    CERN Document Server

    Witharana, Sanjeeva; Xu, Dan; Lai, Xiaojun; Ding, Yulong

    2012-01-01

    Nanoparticle suspensions (also called nanofluids) are often polydisperse and tend to settle with time. Settling kinetics in these systems are known to be complex and hence challenging to understand. In this work, polydisperse spherical alumina (Al2O3) nanoparticles in the size range of ~10-100nm were dispersed in water and examined for aggregation and settling behaviour near its isoelectric point (IEP). A series of settling experiments were conducted and the results were analysed by photography and by Small Angle X-ray Scattering (SAXS). The settling curve obtained from standard bed height measurement experiments indicated two different types of behaviour, both of which were also seen in the SAXS data. But the SAXS data were remarkably able to pick out the rapid settling regime as a result of the high temporal resolution (10s) used. By monitoring the SAXS intensity, it was further possible to record the particle aggregation process for the first time. Optical microscopy images were produced on drying and drie...

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

    Science.gov (United States)

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

    2016-04-01

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

  20. Pure and aerated water entry of a flat plate

    Science.gov (United States)

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

    2016-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  2. Tank 241-S-111: Tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, ORNL, and PNL tank vapor program. Scope of this plan is to provide guidance for sampling and analysis of vapor samples from tank 241-S-111 (this tank is on the organic and flammable gas watch list). This tank received Redox plant waste, among other wastes

  3. Tank 241-U-204 tank characterization plan

    International Nuclear Information System (INIS)

    This document is the tank characterization plan for Tank 241-U-204 located in the 200 Area Tank Farm on the Hanford Reservation in Richland, Washington. This plan describes Data Quality Objectives (DQO) and presents historical information and scheduled sampling events for tank 241-U-204

  4. Tank 241-S-111: Tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Homi, C.S.

    1995-03-07

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, ORNL, and PNL tank vapor program. Scope of this plan is to provide guidance for sampling and analysis of vapor samples from tank 241-S-111 (this tank is on the organic and flammable gas watch list). This tank received Redox plant waste, among other wastes.

  5. Improvement performance of Al-Wathba settling tank by a computational fluid dynamics model

    OpenAIRE

    Kriš, Jozef; Hadi, Ghawi A.

    2010-01-01

    An investigation has been carried out using the FLUENT Computational Fluid Dynamics (CFD) software, which uses the finite-volume method to determine whether it is feasible to improve the capacity and quality of the clarifier at the Al-Wathba Water Treatment Works (Iraq) by some relatively inexpensive means. Simulations were carried out with two dimensional, radially symmetric models, representing the existing configuration as well as a number of proposed modifications involving baffles and ad...

  6. Lattice Boltzmann simulations of settling behaviors of irregularly shaped particles

    Science.gov (United States)

    Zhang, Pei; Galindo-Torres, S. A.; Tang, Hongwu; Jin, Guangqiu; Scheuermann, A.; Li, Ling

    2016-06-01

    We investigated the settling dynamics of irregularly shaped particles in a still fluid under a wide range of conditions with Reynolds numbers Re varying between 1 and 2000, sphericity ϕ and circularity c both greater than 0.5, and Corey shape factor (CSF) less than 1. To simulate the particle settling process, a modified lattice Boltzmann model combined with a turbulence module was adopted. This model was first validated using experimental data for particles of spherical and cubic shapes. For irregularly shaped particles, two different types of settling behaviors were observed prior to particles reaching a steady state: accelerating and accelerating-decelerating, which could be distinguished by a critical CSF value of approximately 0.7. The settling dynamics were analyzed with a focus on the projected areas and angular velocities of particles. It was found that a minor change in the starting projected area, an indicator of the initial particle orientation, would not strongly affect the settling velocity for low Re. Periodic oscillations developed for all simulated particles when Re>100 . The amplitude of these oscillations increased with Re. However, the periods were not sensitive to Re. The critical Re that defined the transition between the steady and periodically oscillating behaviors depended on the inertia tensor. In particular, the maximum eigenvalue of the inertia tensor played a major role in signaling this transition in comparison to the intermediate and minimum eigenvalues.

  7. Feed tank transfer requirements

    International Nuclear Information System (INIS)

    This document presents a definition of tank turnover. Also, DOE and PC responsibilities; TWRS DST permitting requirements; TWRS Authorization Basis (AB) requirements; TWRS AP Tank Farm operational requirements; unreviewed safety question (USQ) requirements are presented for two cases (i.e., tank modifications occurring before tank turnover and tank modification occurring after tank turnover). Finally, records and reporting requirements, and documentation which will require revision in support of transferring a DST in AP Tank Farm to a privatization contractor are presented

  8. Ethanol production from xylose by pichia stipitis NRRL Y-7124 in a stirred tank bioreactor

    OpenAIRE

    Silva, J. P. A.; S. I. Mussatto; Roberto, I. C.; Teixeira, J.A.

    2011-01-01

    The ethanol production by Pichia stipitis was evaluated in a stirred tank bioreactor using semi-defined medium containing xylose (90.0 g/l) as the main carbon source. Experimental assays were performed according to a 2² full factorial design to evaluate the influence of aeration (0.25 to 0.75 vvm) and agitation (150 to 250 rpm) conditions on ethanol production. In the studied range of values, the agitation increase and aeration decrease favored ethanol production, which was maximum (26.7 g/l)...

  9. A study of aeration treatment of uranium-contained wastewater by saccharomyces cerevisiae-activated sludge

    International Nuclear Information System (INIS)

    Experiments of the aeration treatment of uranium-contained wastewater by saccharomyces cerevisiae-activated sludge were carried out. The experimental results indicate that, saccharomyces cerevisiae (S.C) can accumulate UO22+ effectively from aqueous solution: the removal ratio of 100 mg·L-1 UO22+ is 78.2% when S.C dosage is 10 g·L-1, while with 8 g·L-1 activated sludge (A.S.) added in the solution the ratio has increased to 96.3%; then, 5-10 min effluent settling is clarified as a result of sludge flocculation; the optimum conditions of biosorption of U from wastewater by S.C.-A.S. are at pH 5, A.S concentration=8 g·L-1, added dry weight of S.C.=10 g·L-1, granularity of S.C=100-120 mesh; the quantity of U increases with the enhanced initial concentration of UO22+ in the process of biosorption by S.C.-A.S., but the removal ratio decreases. The uptake of U could be described by the Freundlich and the Langmuir adsorption isotherms, which demonstrated that the adsorption was regarded as a physical adsorption. (authors)

  10. Results Of Initial Analyses Of The Macrobatch 7 Tank 21H Qualification Samples

    International Nuclear Information System (INIS)

    Savannah River National Laboratory (SRNL) analyzed samples from Tank 21H in support of qualification of Salt (Macro) Batch 7 for the Interim Salt Disposition Program (ISDP) through ARP/MCU. This document reports the initial results of the analyses of samples of Tank 21H. Further results on the chemistry and other tests will be issued in the future. No issues with the projected Salt Batch 7 strategy are identified, other than the presence of visible quantities of dark colored solids. Based upon a SRNL settling test, the solids should settle well within the months-long settling period to be employed in Tank 21H. However, SRNL recommends analyzing the solids to provide input to OLI modeling in order to evaluate the impacts of these solids to present and future salt batches

  11. Tank Insulation

    Science.gov (United States)

    1979-01-01

    For NASA's Apollo program, McDonnell Douglas Astronautics Company, Huntington Beach, California, developed and built the S-IVB, uppermost stage of the three-stage Saturn V moonbooster. An important part of the development task was fabrication of a tank to contain liquid hydrogen fuel for the stage's rocket engine. The liquid hydrogen had to be contained at the supercold temperature of 423 degrees below zero Fahrenheit. The tank had to be perfectly insulated to keep engine or solar heat from reaching the fuel; if the hydrogen were permitted to warm up, it would have boiled off, or converted to gaseous form, reducing the amount of fuel available to the engine. McDonnell Douglas' answer was a supereffective insulation called 3D, which consisted of a one-inch thickness of polyurethane foam reinforced in three dimensions with fiberglass threads. Over a 13-year development and construction period, the company built 30 tanks and never experienced a failure. Now, after years of additional development, an advanced version of 3D is finding application as part of a containment system for transporting Liquefied Natural Gas (LNG) by ship.

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

    Science.gov (United States)

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

    2010-08-01

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

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

    International Nuclear Information System (INIS)

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

  14. Experimental Analysis of Pressure Fluctuations behind a Bottom Aerator

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

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

  15. RE-AERATION LAW OF WATER FLOW OVER SPILLWAYS

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  16. Studies of radon mitigation in well water by aeration

    International Nuclear Information System (INIS)

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

  17. An Analysis of Nanoparticle Settling Times in Liquids

    CERN Document Server

    Liyanage, D D; Kumbalatara, A A K; Weliwita, J A; Witharana, S

    2016-01-01

    Aggregation and settling are crucial phenomena that involve particulate systems. For particle sizes of millimetre and above, there are reasonable accurate predicting tools. However for smaller particle sizes, there appears to be a void in knowledge. This paper presents an analytical model to predict the settling rates of nano-to-micro size particulate systems. The model was developed as a combination of modified classical equations and graphical methods. A calculation sequence also is presented. By validation with available experimental data for settling nano-to-micro systems, it was found that the two schemes show order of magnitude agreement. A significant feature of this model is its ability to accommodate non-spherical particles and different fractal dimensions.

  18. Characterization of the variability of settling in wastewater treatment

    International Nuclear Information System (INIS)

    The processes of biological treatment of wastewater in activated sludge are complex dynamic processes are difficult to manage. The ability of the sludge settling is a key parameter for the overall effectiveness of pollution control process and for preserving the quality of the receiving environment. So for better management of wastewater treatment plants, a study of interactions between the couple reactor clarifier is necessary. A new management technique must notify the operator to problems related to sludge mainly to the loss of the sludge blanket which will have adverse effects on the environment. The approach is widely adopted and applied an approach aims to identify factors that may explain the observed phenomena in order to draw strategies that could improve the sludge settling on an industrial scale. The widely used approach is based on measuring Mohlman index and gives an impression, on the ability of the mud settling, but does not prevent the operator to anomalies that have places in the decanter.

  19. Investigating the effect of ballasting by CaCO 3 in Emiliania huxleyi: I. Formation, settling velocities and physical properties of aggregates

    Science.gov (United States)

    Engel, Anja; Szlosek, Jennifer; Abramson, Lynn; Liu, Zhanfei; Lee, Cindy

    2009-08-01

    To investigate the role of ballasting by biogenic minerals in the export of organic matter in the ocean, a laboratory experiment was conducted comparing aggregate formation and settling velocity of non-calcifying and calcifying strains of the coccolithophore Emiliania huxleyi. Experiments were conducted by making aggregates using a roller table and following aggregate properties during incubation for a period of 40 days. Size, shape, and settling velocities of aggregates were described by image analysis of video pictures recorded during the roller tank incubation. Our results show that biogenic calcite has a strong effect on the formation rate and abundance of aggregates and on aggregate properties such as size, excess density, porosity, and settling velocity. Aggregates of calcifying cells (AGG CAL) formed faster, were smaller and had higher settling velocities, excess densities, and mass than those of non-calcifying cells (AGG NCAL). AGG CAL showed no loss during the duration of the experiment, whereas AGG NCAL decreased in size after 1 month of incubation. Potential mechanisms that can explain the different patterns in aggregate formation are discussed. Comparison of settling velocities of AGG CAL and AGG NCAL with aggregates formed by diatoms furthermore indicated that the ballast effect of calcite is greater than that of opal. Together these results help to better understand why calcite is of major importance for organic matter fluxes to the deep ocean.

  20. Settling-velocity specific SOC distribution on hillslopes

    Science.gov (United States)

    Hu, Yaxian; Asefaw Berhe, Asmeret; Fogel, Marilyn L.; Heckrath, Goswin J.; Kuhn, Nikolaus J.

    2016-04-01

    The net effect of soil erosion by water, as a sink or source of atmospheric CO2, is determined by the spatial (re-)distribution and stability of eroded soil organic carbon (SOC). The depositional position of eroded SOC is a function of the transport distances of soil fractions where the SOC is stored. In theory, the transport distances of soil fractions are related to their settling velocities under given flow conditions. Yet, very few field investigations have been conducted to examine the actual movement of eroded soil fractions along hillslopes, let alone the re-distribution pattern of SOC fractions. Eroding sandy soils and sediment were sampled after a series of rainfall events along a slope on a freshly seeded cropland in Jutland, Denmark. All the soil samples were fractionated into five settling classes using a settling tube apparatus. The spatial distribution of soil settling classes shows a coarsening effect immediately below the eroding slope, followed by a fining trend at the slope tail. The δ13C values of soil fractions were more positive at the footslope than on the slope shoulder or at the slope tail, suggesting enhanced decomposition rate of fresh SOC input at the footslope during or after erosion-induced transport. Overall, our results illustrate that immediate deposition of fast settling soil fractions and the associated SOC at footslopes must be appropriately accounted for in attempts to quantify the role of soil erosion in terrestrial carbon sequestration. A SOC erodibility parameter based on actual settling velocity distribution of eroded fractions is needed to better calibrate soil erosion models.

  1. INVESTIGATION ON THE SPLASH LENGTH OF THE AERATED JET

    Institute of Scientific and Technical Information of China (English)

    Liu Shi-he; Qu Bo

    2003-01-01

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

  2. Hydrodynamic behaviour of the lateral flow biological aerated filter

    Institute of Scientific and Technical Information of China (English)

    HE Qiang; WANG Yin; FANG Jun-hua; ZHANG Hong-jing; XU Jing

    2006-01-01

    Pulsed signal experiment was carried out to determine the hydrodynamic behaviours of lateral flow biological aerated filter(LBAF). With the analysis of experimental results, LBAF is viewed as an approximate plug flow reactor, and hydraulic retention time distribution function was derived based on LBAF. The results show that flow rate and aeration strength are two critical factors which influence flow patterns in LBAF reactor. The hydrodynamic behaviour analysis of LBAF is the theoretical basis of future research on improving capacity factor and developing kinetic model for the reactor.

  3. AERATION EFFECT OF SUBMERGED JET ON HYDRAULIC CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A water-air two-phase turbulence mathematical model was proposed, The mass-weighted average was adoptedfor velocity, air mass fraction and turbulent parameters. Thealgebraic stress equation was used to calculate the Reynoldsstress. The pulsating flux of air mass fraction was simulatedby employing the concept of the eddy viscosity. The numericalsimulation of aerated flow in plunge pool shows that, for the same depth, aeration may decrease the time-averaged pressureon pool floor and increase slightly the turbulent intensity. Thecomputed concentration and pressure distributions coincidewith the experimental data.

  4. Characteristics of integrated biological aerated filter in municipal wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    HE Qiang; ZHANG Yu-ping; XU Jian-bin

    2005-01-01

    In this paper, the characteristics of integrated biological aerated filter (IBAF) applied to municipal wastewater treatment were studied in a pilot scale experiment. The experimental results showed that IBAF has high efficiencies in removing organic pollutants, such as CODCr and SS, in municipal wastewater. The removal rates of CODCr and SS can reach over 90% and 80%, respectively, when COD and SS in the influent are 234 mg L-1 and 112 mg L-1, hydraulic retention time (HRT) is 8 h, and the aerated intensity is in the range of (0.5 to 0.6) L m-2 s-1.

  5. Relation between Shunt, Aeration, and Perfusion in Experimental Acute Lung Injury

    OpenAIRE

    Musch, Guido; Bellani, Giacomo; Vidal Melo, Marcos F; Harris, R. Scott; Winkler, Tilo; Schroeder, Tobias; Venegas, Jose G

    2007-01-01

    Rationale: In a pulmonary process characterized by spatially heterogeneous loss of aeration, the impairment of gas exchange is expected to depend on the regional distribution of perfusion relative to that of aeration.

  6. 49 CFR 172.331 - Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. 172.331 Section 172.331 Transportation Other Regulations... packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. (a) Each...

  7. Swarms of particles settling under gravity in a viscous fluid

    CERN Document Server

    Ekiel-Jezewska, Maria L

    2012-01-01

    We investigate swarms made of a small number of particles settling under gravity in a viscous fluid. The particles do not touch each other and can move relative to each other. The dynamics is analyzed in the point-particle approximation. A family of swarms is found with periodic oscillations of all the settling particles. In the presence of an additional particle above the swarm, the trajectories are horizontally repelled from the symmetry axis, and flattened vertically. The results are used to explain how a spherical cloud, made of a large number of particles distributed at random, evolves and destabilizes.

  8. Modeling of Spinel Settling in Waste Glass Melter

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel; Schill, Petr; Nemec, Lubomir; Klouzek, Jaroslav, Mika, Martin; Brada, Jiri Glass Service, Ltd., Vsetin, Czech Republic

    2000-06-01

    Our objective is to determine the fraction and size of spinel crystals in molten HLW glass that are compatible with low-risk melter operation. To this end, we are investigating spinel behavior in HLW glass and obtaining data to be used in a mathematical model for spinel settling in a HLW glass melter. We will modify the current glass-furnace model to incorporate spinel concentration distribution and to predict the rate of spinel settling. Also, we will determine the nucleation agents that control the number density and size of spinel crystals in HLW glass.

  9. Sequential Aeration of Membrane-Aerated Biofilm Reactors for High-Rate Autotrophic Nitrogen Removal: Experimental Demonstration

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Sun, Sheng-Peng; Lackner, Susanne;

    2010-01-01

    One-stage autotrophic nitrogen (N) removal, requiring the simultaneous activity of aerobic and anaerobic ammonium oxidizing bacteria (AOB and AnAOB), can be obtained in spatially redox-stratified biofilms. However, previous experience with Membrane-Aerated Biofilm Reactors (MABRs) has revealed a...... difficulty in reducing the abundance and activity of nitrite oxidizing bacteria (NOB), which drastically lowers process efficiency. Here we show how sequential aeration is an effective strategy to attain autotrophic N removal in MABRs: Two separate MABRs, which displayed limited or no N removal under......S rRNA gene confirmed that sequential aeration, even at elevated average O2 loads, stimulated the abundance of AnAOB and AOB and prevented the increase in NOB. Nitrous oxide (N2O) emissions were 100-fold lower compared to other anaerobic ammonium oxidation (Anammox)-nitritation systems. Hence, by...

  10. Mechanisms of ammonium transformation and loss in intermittently aerated leachfield soil.

    Science.gov (United States)

    Richard, John T; Potts, David A; Amador, José A

    2014-11-01

    Optimization of N removal in soil-based wastewater treatment systems requires an understanding of the microbial processes involved in N transformations. We examined the fate of NH in intermittently aerated leachfield mesocosms over a 24-h period. Septic tank effluent (STE) was amended with NHCl to help determine N speciation and distribution in drainage water, soil, and headspace gases. Our results show that 5.7% of the N was found in soil, 10.0% in drainage water, and 84.3% in the gas pool. Ammonium accounted for 41.7% of the soil N pool, followed by NO (29.2%), organic N (21.7%), and microbial biomass N (7.5%). In drainage water, NO constituted ∼80% of the N pool, whereas NH was absent from this pool. Nitrous oxide was the dominant form of N in the gas phase 6 h after addition of NH-amended STE to the mesocosms, after which its mass declined exponentially; by contrast, the mass of N was initially low but increased linearly with time to become the dominant form of N after 24 h. Analysis based on the isotopic enrichment of NO and N indicates that nitrification contributed 98.8 and 23.1% of the NO flux after 6 and 24 h, respectively. Our results show that gaseous losses are the main mechanism for NH removal from wastewater in intermittently aerated soil. In addition, nitrification, which is generally not considered a significant pathway for N loss in soil-based wastewater treatment, is an important source process for NO. PMID:25602229

  11. Development and evaluation of a new aerator for the catfish industry

    Science.gov (United States)

    Traditional paddle-wheel aerators have been used for supplemental and emergency aeration in the aquaculture industry for over 30 years but distribute a high volume of water which dilutes the aeration effort over the entire pond volume. Thus, a great deal of equipment and a large amount of power is r...

  12. Influence of aeration degree of cultural liquid on biosintetical activity of fungus culture Blakeslea trispora

    OpenAIRE

    A. S. Anatsky; Y. A. Kunshchikova

    2009-01-01

    Β-carotene biosynthetic processes of the fungus Blakeslea trispora are studied for different technological modes of cultural liquid aeration under industrial conditions. It is shown, that the increase of aeration degree stimulates the accumulation of biomass and carotene’s formation. The operating practices of the maximal aeration since the 10th hour of cultivation are recommended to the use.

  13. Effect of pond aeration on growth and survival of Penaeus monodon Fab.

    OpenAIRE

    R. K. Mohanty

    2001-01-01

    The effect of paddle wheel aeration on shrimp growth and survival were studied at a commercial farm at Chandipur coast of Orissa, India, at different stocking densities of Penaeus monodon. Four different aeration patterns were adopted and evaluated. Influence of individual aeration pattern on average survival rate was not highly significant (p

  14. Intermittent aeration to improve wastewater treatment efficiency in pilot-scale constructed wetland.

    Science.gov (United States)

    Uggetti, Enrica; Hughes-Riley, Theodore; Morris, Robert H; Newton, Michael I; Trabi, Christophe L; Hawes, Patrick; Puigagut, Jaume; García, Joan

    2016-07-15

    Forced aeration of horizontal subsurface flow constructed wetlands (HSSF CWs) is nowadays a recognized method to improve treatment efficiency, mainly in terms of ammonium removal. While numerous investigations have been reported testing constant aeration, scarce information can be found about the efficiency of intermittent aeration. This study aims at comparing continuous and intermittent aeration, establishing if there is an optimal regime that will increase treatment efficiency of HSSF CWs whilst minimizing the energy requirement. Full and intermittent aeration were tested in a pilot plant of three HSSF CWs (2.64m(2) each) fed with primary treated wastewater. One unit was fully aerated; one intermittently aerated (i.e. by setting a limit of 0.5mg/L dissolved oxygen within the bed) with the remaining unit not aerated as a control. Results indicated that intermittent aeration was the most successful operating method. Indeed, the coexistence of aerobic and anoxic conditions promoted by the intermittent aeration resulted in the highest COD (66%), ammonium (99%) and total nitrogen (79%) removals. On the other hand, continuous aeration promotes ammonium removal (99%), but resulted in nitrate concentrations in the effluent of up to 27mg/L. This study demonstrates the high potential of the intermittent aeration to increase wastewater treatment efficiency of CWs providing an extreme benefit in terms of the energy consumption. PMID:27062558

  15. Directional Flow of Summer Aeration to Manage Insect Pests in Stored Wheat

    Science.gov (United States)

    Field trials were conducted in metal wheat storage bins to determine whether pressure aeration, pushing ambient air from the bottom, or suction aeration, pulling air down from the top, would be more efficient at cooling the wheat mass and thereby limiting insect population growth. Aeration was accom...

  16. 7 CFR 201.55a - Moisture and aeration of substratum.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Moisture and aeration of substratum. 201.55a Section... and aeration of substratum. (a) The substratum must be moist enough to supply the needed moisture to the seeds at all times. Excessive moisture which will restrict aeration of the seeds should be...

  17. Interaction of two spheres settling in a linearly stratified fluid

    Science.gov (United States)

    Mercier, Matthieu; Toupoint, Clement; Ern, Patricia

    2015-11-01

    The settling dynamics of small objects in stratified fluids is important to understand the fate of the biomass in lakes or oceanic environments, for industrial applications such as waste-water disposal. More specifically, the interaction of two settling bodies is a fundamental problem recently studied numerically for spheres. Experimental results are needed for validation, especially at low and moderate values of the Reynolds number, for different values of the Froude number, the other parameter of interest. We present experimental results on the interaction of two spheres settling in a linearly stratified fluid. The settling dynamics is investigated by tracking their trajectories in three dimensions, using a pair of cameras imaging two perpendicular planes. Two typical cases are observed, the horizontal repulsion of particles initially aligned horizontally, and the Drafting-Kissing-Tumbling of spheres initially aligned vertically. The influence of the initial positions of the spheres, the Reynolds and Froude numbers, is investigated to quantify these effects and their robustness, in comparison to the dynamics in an homogeneous fluid.

  18. Probing Dust Settling in Proto-planetary Disks with ALMA

    CERN Document Server

    Boehler, Y; Guilloteau, S; Piétu, V; 10.1093/mnras/stt278

    2013-01-01

    Investigating the dynamical evolution of dust grains in proto-planetary disks is a key issue to understand how planets should form. We identify under which conditions dust settling can be constrained by high angular resolution observations at mm wavelengths, and which observational strategies are suited for such studies. Exploring a large range of models, we generate synthetic images of disks with different degrees of dust settling, and simulate high angular resolution (~ 0.05-0.3") ALMA observations of these synthetic disks. The resulting data sets are then analyzed blindly with homogeneous disk models (where dust and gas are totally mixed) and the derived disk parameters are used as tracers of the settling factor. Our dust disks are partially resolved by ALMA and present some specific behaviors on radial and mainly vertical directions, which can be used to quantify the level of settling. We find out that an angular resolution better than or equal to ~ 0.1" (using 2.3 km baselines at 0.8mm) allows us to cons...

  19. Settling of a cylindrical particle in a stagnant fluid

    DEFF Research Database (Denmark)

    Sørensen, Henrik; Rosendahl, Lasse; Yin, Chungen;

    2007-01-01

    The objective of this work is to collect data and develop models for cylindrical particles which could be used in numerical multiphase flow modeling. Trajectories of cylindrical particles settling in stagnant water are filmed from two directions in order to derive detailed information on their...

  20. Geochemistry of suspended and settling solids in two freshwater lakes.

    NARCIS (Netherlands)

    Koelmans, A.A.

    1998-01-01

    This study describes the 1987–1992 time variationof the bulk chemical composition, levels of heavymetals, arsenic, nitrogen and phosporous insuspended and settling solids in Lake Volkerak andLake Zoom (The Netherlands). Suspended and setlingsolids were collected with continuous flowcentrifuges and s

  1. MODELING OF SPINEL SETTLING IN WASTE GLASS MELTER

    Science.gov (United States)

    The topic of this multi-institutional bi-national research is the formation and settling of spinel, the most common crystalline phase that precipitates in molten high-level waste HLW) glass. For the majority of HLW streams, spinel formation in the HLW melter limits the waste fra...

  2. Manganese uptake and its redistribution in sugar cane settlings

    International Nuclear Information System (INIS)

    Investigation was conducted to study manganese uptake and partitioning after 2 hr of feeding and its redistribution in settlings after 30 days of growth in two cultivars of sugar cane which differed in their yield, maturity and nutritional and physiological characteristics. (author). 6 refs

  3. SVOC partitioning between the gas phase and settled dust indoors

    DEFF Research Database (Denmark)

    Weschler, Charles J.; Nazaroff, W. W.

    2010-01-01

    Semivolatile organic compounds (SVOCs) are a major class of indoor pollutants. Understanding SVOC partitioning between the gas phase and settled dust is important for characterizing the fate of these species indoors and the pathways by which humans are exposed to them. Such knowledge also helps in...

  4. Non-autoclaved aerated concrete with mineral additives

    Science.gov (United States)

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

    2016-01-01

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

  5. Little River Pond Mill a wind-powered lagoon aerator

    International Nuclear Information System (INIS)

    The Little River Pond Mill is a wind-driven surface aerator designed to be used in facultative wastewater treatment plants. The aerator consists of an eight-blade wind turbine which is mounted to a gear box that transmits torque through the shaft to the impeller. A swing tail rotates the turbine into the wind and stabilizes the unit in high winds. This study was designed to investigate how the Little River Pond Mill operated in a lagoon environment, how it affected the performance of the lagoon, and to measure the oxygen transfer rate for a field-determined wind speed. Strong mixing capabilities have been observed in both the dugout and the lagoon installations even at low windspeeds. With the installation of the aerator there was a reduction in BOD and NH3N. The oxygen transfer rate was found to be 1.47 g O2/W h at an average wind speed of 19 km/h. Due to the Pond Mill's low power requirement, this aeration efficiency has been rated as 'quite reasonable' for this wind speed. 5 refs., 10 figs

  6. Tailwater concerns and the history of turbine aeration

    International Nuclear Information System (INIS)

    All new proposals for hydropower development and many of the almost 300 hydroelectric projects which will be relicensed before 2000 will have to address the issue of minimum dissolved oxygen concentrations. This paper highlights some of the causes and concerns of low dissolved oxygen concentrations in releases from hydropower projects and describes the history of hydroturbine aeration for reaerating these releases

  7. Fin characteristics of aerator devices with lateral deflectors

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; LI Dan; MA Fei; QIAN Shang-tuo

    2013-01-01

    The fins will be formed if the lateral deflectors in the side-walls with a bottom aerator device are improperly designed,and the flow regime downstream of the aerator device will be worsened.In this paper,the height and the length of the fins induced by the lateral deflectors are theoretically analyzed along with their influencing factors,and the fin characteristics are experimentally investigated on the basis of the theoretical analysis.It is shown that the intensities of the fins are strongly dependent on the ratio of the lateral cavity length to the bottom cavity length,and other factors,like the working head,the height and the angle of the lateral deflector,the flow Froude number around the aerator device,affect the fins indirectly through the changes of the lateral cavity length.When an aerator device with lateral deflectors is designed,it is crucial to match the above mentioned ratio,and to make the ratio of the two cavity lengths less than 1.0 in order to avoid the generation of the fins.

  8. No-till bioenergy cropping systems effect on soil aeration

    Science.gov (United States)

    Bioenergy cropping systems have been proposed as a way to enhance United States energy security. However, research on soil quality, such as the effects of maize stover harvesting on soil aeration and the relationships to soil structure and water, associated with bioenergy cropping systems has been l...

  9. HYDRAULIC CHARACTERISTICS OF CHUTE AERATORS FOR RELEASE WORKS

    Institute of Scientific and Technical Information of China (English)

    RUAN Shi-ping

    2008-01-01

    On the basis of model tests and theoretical analysis, hydraulic characteristics, air demand, air concentration distribution and their relationships between prototype and model of an aerator were studied. Some computational examples show that the present methods have higher accuracy, and can meet the need of engineering design.

  10. Aeration of bread dough influenced by different way processing

    NARCIS (Netherlands)

    Peighambardoust, S.H.; Fallah, E.; Hamer, R.J.; Goot, van der A.J.

    2010-01-01

    The effect of steady shearing versus z-blade mixing on mechanical aeration and gas retaining ability of the dough during processing and subsequent proofing and bread baking stages was investigated. Reduction in moisture content led to reduction in both static and dynamic densities of z-blade mixed d

  11. Nutrients removal using moving beds with aeration cycles

    International Nuclear Information System (INIS)

    Moving Bed Biofilm Reactors (MBBR) are based on the biomass growth over a media that moves into the reactor due to aeration, mechanical agitation or recirculation. These reactors have been gaining popularity and they are employed in hundreds of plants everywhere with different treatment purposes (organic matter removal, nitrification/denitrification), both for urban and industrial wastewater. (Author)

  12. Settling velocity of marine microplastic particles: laboratory tests

    Science.gov (United States)

    Isachenko, Igor; Khatmullina, Lilia; Chubarenko, Irina; Stepanova, Natalia

    2016-04-01

    An assessment of the settling velocity of different classes of microplastic particles (105). Even for such transitional regime, the settling velocity of the particles that could be treated as more or less smooth spheres can be predicted with high accuracy by relationships available in publications. This is not the case for the non-spherical particles like fibres or flakes. There are quite a large number of quasi-theoretical or semi-empirical approaches that take into account the shape and roughness of the particles, usually in the applications to transport of natural sediments. Some engineering formulas for the settling velocity are also developed which have simpler structure along with high degree of accuracy on the set of experimental data. For marine microplastic particles, the absence of relationship between the settling velocity and the properties of the particle requires testing on the samples of marine microplastics. Besides small fragments of rigid plastic (granules, microbeads), there are also fibres and thin plastic sheets (flakes) with some degree of flexibility. The applicability of available formulae to thin and/or flexible plastic particles again requires verification by experiments. The set of laboratory experiments on settling of microplastic particles of various shapes and excess densities in homogeneous water is reported. The particles were collected in water column, bottom sediments and on the beaches of the South-Eastern Baltic. The experiments demonstrate not just different regimes of motion but different manner of the sinking of spheres, flakes and fibres. The very definition of the "settling velocity" has a specific meaning for every kind of a particle shape. The results of test measurements are compared with predictions by several published semi-empirical formulae. We conclude that there are several new questions to discuss in this regard: (i) proper definition of the meaning of "settling velocity" for complicated motion of particles of

  13. Aggregate Settling Velocities in San Francisco Estuary Margins

    Science.gov (United States)

    Allen, R. M.; Stacey, M. T.; Variano, E. A.

    2015-12-01

    One way that humans impact aquatic ecosystems is by adding nutrients and contaminants, which can propagate up the food web and cause blooms and die-offs, respectively. Often, these chemicals are attached to fine sediments, and thus where sediments go, so do these anthropogenic influences. Vertical motion of sediments is important for sinking and burial, and also for indirect effects on horizontal transport. The dynamics of sinking sediment (often in aggregates) are complex, thus we need field data to test and validate existing models. San Francisco Bay is well studied and is often used as a test case for new measurement and model techniques (Barnard et al. 2013). Settling velocities for aggregates vary between 4*10-5 to 1.6*10-2 m/s along the estuary backbone (Manning and Schoellhamer 2013). Model results from South San Francisco Bay shoals suggest two populations of settling particles, one fast (ws of 9 to 5.8*10-4 m/s) and one slow (ws of < 1*10-7 to 1.4*10-5 m/s) (Brand et al. 2015). While the open waters of San Francisco Bay and other estuaries are well studied and modeled, sediment and contaminants often originate from the margin regions, and the margins remain poorly characterized. We conducted a 24 hour field experiment in a channel slough of South San Francisco Bay, and measured settling velocity, turbulence and flow, and suspended sediment concentration. At this margin location, we found average settling velocities of 4-5*10-5 m/s, and saw settling velocities decrease with decreasing suspended sediment concentration. These results are consistent with, though at the low end of, those seen along the estuary center, and they suggest that the two population model that has been successful along the shoals may also apply in the margins.

  14. AX Tank Farm tank removal study

    Energy Technology Data Exchange (ETDEWEB)

    SKELLY, W.A.

    1999-02-24

    This report examines the feasibility of remediating ancillary equipment associated with the 241-AX Tank Farm at the Hanford Site. Ancillary equipment includes surface structures and equipment, process waste piping, ventilation components, wells, and pits, boxes, sumps, and tanks used to make waste transfers to/from the AX tanks and adjoining tank farms. Two remedial alternatives are considered: (1) excavation and removal of all ancillary equipment items, and (2) in-situ stabilization by grout filling, the 241-AX Tank Farm is being employed as a strawman in engineering studies evaluating clean and landfill closure options for Hanford single-shell tanks. This is one of several reports being prepared for use by the Hanford Tanks Initiative Project to explore potential closure options and to develop retrieval performance evaluation criteria for tank farms.

  15. Ventilation/perfusion mismatch during lung aeration at birth.

    Science.gov (United States)

    Lang, Justin A R; Pearson, James T; te Pas, Arjan B; Wallace, Megan J; Siew, Melissa L; Kitchen, Marcus J; Fouras, Andreas; Lewis, Robert A; Wheeler, Kevin I; Polglase, Graeme R; Shirai, Mikiyasu; Sonobe, Takashi; Hooper, Stuart B

    2014-09-01

    At birth, the transition to newborn life is triggered by lung aeration, which stimulates a large increase in pulmonary blood flow (PBF). Current theories predict that the increase in PBF is spatially related to ventilated lung regions as they aerate after birth. Using simultaneous phase-contrast X-ray imaging and angiography we investigated the spatial relationships between lung aeration and the increase in PBF after birth. Six near-term (30-day gestation) rabbits were delivered by caesarean section, intubated and an intravenous catheter inserted, before they were positioned for X-ray imaging. During imaging, iodine was injected before ventilation onset, after ventilation of the right lung only, and after ventilation of both lungs. Unilateral ventilation increased iodine levels entering both left and right pulmonary arteries (PAs) and significantly increased heart rate, iodine ejection per beat, diameters of both left and right PAs, and number of visible vessels in both lungs. Within the 6th intercostal space, the mean gray level (relative measure of iodine level) increased from 68.3 ± 11.6 and 70.3 ± 7.5%·s to 136.3 ± 22.6 and 136.3 ± 23.7%·s in the left and right PAs, respectively. No differences were observed between vessels in the left and right lungs, despite the left lung not initially being ventilated. The increase in PBF at birth is not spatially related to lung aeration allowing a large ventilation/perfusion mismatch, or pulmonary shunting, to occur in the partially aerated lung at birth. PMID:24994883

  16. The potential for aeration of MSW landfills to accelerate completion

    International Nuclear Information System (INIS)

    Landfilling is a popular waste disposal method, but, as it is practised currently, it is fundamentally unsustainable. The low short-term financial costs belie the potential long-term environmental costs, and traditional landfill sites require long-term management in order to mitigate any possible environmental damage. Old landfill sites might require aftercare for decades or even centuries, and in some cases remediation may be necessary. Biological stabilisation of a landfill is the key issue; completion criteria provide a yardstick by which the success of any new technology may be measured. In order for a site to achieve completion it must pose no risk to human health or the environment, meaning that attenuation of any emissions from the site must occur within the local environment without causing harm. Remediation of old landfill sites by aerating the waste has been undertaken in Germany, the United States, Italy and The Netherlands, with considerable success. At a pilot scale, aeration has also been used in newly emplaced waste to accelerate stabilisation. This paper reviews the use of aerobic landfill worldwide, and assesses the ways in which the use of aerobic landfill techniques can decrease the risks associated with current landfill practices, making landfill a more sustainable waste disposal option. It focuses on assessing ways to utilise aeration to enhance stabilisation. The results demonstrated that aeration of old landfill sites may be an efficient and cost-effective method of remediation and allow the date of completion to be brought forward by decades. Similarly, aeration of newly emplaced waste can be effective in enhancing degradation, assisting with completion and reducing environmental risks. However, further research is required to establish what procedure for adding air to a landfill would be most suitable for the UK and to investigate new risks that may arise, such as the possible emission of non-methane organic compounds

  17. Computer modeling of jet mixing in INEL waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, P.A.

    1994-01-01

    The objective of this study is to examine the feasibility of using submerged jet mixing pumps to mobilize and suspend settled sludge materials in INEL High Level Radioactive Waste Tanks. Scenarios include removing the heel (a shallow liquid and sludge layer remaining after tank emptying processes) and mobilizing and suspending solids in full or partially full tanks. The approach used was to (1) briefly review jet mixing theory, (2) review erosion literature in order to identify and estimate important sludge characterization parameters (3) perform computer modeling of submerged liquid mixing jets in INEL tank geometries, (4) develop analytical models from which pump operating conditions and mixing times can be estimated, and (5) analyze model results to determine overall feasibility of using jet mixing pumps and make design recommendations.

  18. 49 CFR 172.330 - Tank cars and multi-unit tank car tanks.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Tank cars and multi-unit tank car tanks. 172.330..., TRAINING REQUIREMENTS, AND SECURITY PLANS Marking § 172.330 Tank cars and multi-unit tank car tanks. (a... material— (1) In a tank car unless the following conditions are met: (i) The tank car must be marked...

  19. Aeration to degas CO2, increase pH, and increase iron oxidation rates for efficient treatment of net alkaline mine drainage

    International Nuclear Information System (INIS)

    (II) concentration. The maximum oxidation rate was 1.3 x 10-4 mol L-1 s-1. The model was modified to predict alkalinity, PCO2, dissolved O2, and pH changes based on initial conditions and aeration rate. This more complex model also fits the data well, is more predictive than the first model, and should serve as a tool for predicting pond size needed for aerated Fe(II) oxidation at the field scale without the need for field pilot studies. Iron(II) oxidation modeling of actively aerated systems predicted that a 1-m deep pond with 10 times less area than estimated for passive treatment would lower Fe(II) concentrations to less than 1 mg L-1 at summer and winter temperatures for both sites. The use of active aeration for treatment of CO2-rich, net-alkaline discharges (including partially treated effluent from anoxic limestone drains) can result in considerably reduced treatment area for oxidation and may lower treatment costs, but settling of Fe hydroxides was not considered in this study. The reduced capital cost for earthmoving will need to be compared to energy and maintenance costs for aeration.

  20. Redox potential driven aeration during very-high-gravity ethanol fermentation by using flocculating yeast.

    Science.gov (United States)

    Liu, Chen-Guang; Hao, Xue-Mi; Lin, Yen-Han; Bai, Feng-Wu

    2016-01-01

    Ethanol fermentation requires oxygen to maintain high biomass and cell viability, especially under very-high-gravity (VHG) condition. In this work, fermentation redox potential (ORP) was applied to drive the aeration process at low dissolved oxygen (DO) levels, which is infeasible to be regulated by a DO sensor. The performance and characteristics of flocculating yeast grown under 300 and 260 g glucose/L conditions were subjected to various aeration strategies including: no aeration; controlled aeration at -150, -100 and -50 mV levels; and constant aeration at 0.05 and 0.2 vvm. The results showed that anaerobic fermentation produced the least ethanol and had the highest residual glucose after 72 h of fermentation. Controlled aerations, depending on the real-time oxygen demand, led to higher cell viability than the no-aeration counterpart. Constant aeration triggered a quick biomass formation, and fast glucose utilization. However, over aeration at 0.2 vvm caused a reduction of final ethanol concentration. The controlled aeration driven by ORP under VHG conditions resulted in the best fermentation performance. Moreover, the controlled aeration could enhance yeast flocculating activity, promote an increase of flocs size, and accelerate yeast separation near the end of fermentation. PMID:27161047

  1. Performance of completely autotrophic nitrogen removal over nitrite process under different aeration modes and dissolved oxygen

    Institute of Scientific and Technical Information of China (English)

    Jinsong GUO; Guohong YANG; Fang FANG; Yu QIN

    2008-01-01

    In this study, three sequential batch biofilm reactors (SBBRs) were operated for 155 days to evaluate the performance of completely autotrophic nitrogen removal over nitrite (CANON) process under different aeration modes and dissolved oxygen (DO). Synthetic wastewater with 160-mg NH4+-N/L was fed into the reac-tors. In the continuously-aerated reactor, the efficiency of the ammonium nitrogen conversion and total nitrogen (TN) removal reached 80% and 70%, respectively, with DO between 0.8-1.0 mg/L. Whereas in the intermit-tently-aerated reactor, at the aeration/non-aeration ratio of 1.0, ammonium was always under the detection limit and 86% of TN was removed with DO between 2.0 2.5 mg/L during the aeration time. Results show that CANON could be achieved in both continuous and inter-mittent aeration pattern. However, to achieve the same nitrogen removal efficiency, the DO needed in the inter-mittently-aerated sequential batch biofilm reactor (SBBR) during the aeration period was higher than that in the continuously-aerated SBBR. In addition, the DO in the CANON system should be adjusted to the aeration mode, and low DO was not a prerequisite to CANON process.

  2. Effect of Temperature on Gas Hold—up in Aerated Stirred Tanks

    Institute of Scientific and Technical Information of China (English)

    高正明; 施力田

    2003-01-01

    Gas holdups in ambient gassed and hot sparged systems with multiple modern impellers and the effect of temperature on gas holdup are reported,The operating temperature has a great impact on gas holdup though the gas dispersion regime in the hot sparged system is similar to the ambient gassed condition,The gas holdup under the elevated temperature and the ambient gassed operation is successfully correlated.With the sarme total gas flow rate and power input,the gas holdup in the hot sparged system(say near the boiling point)is only about half of that in the ambient system ,The results imply that almost all existing hot sparged reactors have been designed on the basis of incorrect estimates of the gas holdup during operation.

  3. Hydrodynamic aspects of the design of feed heaters and de-aerator storage tanks

    International Nuclear Information System (INIS)

    Regenerative feed heaters of the direct-contact type and feed water deaerators transmit large quantities of saturated, i.e. boiling, water. Drainage of saturated flows has long been a problem because of the possibility of the flow flashing to steam. Adequate drainage of direct-contact heaters is particularly important because of the danger of condensate returning to the turbine and causing serious damage. Likewise, a deaerator must drain easily or the boiler feed pump to which it drains will lose suction head and cavitate. This paper examines a number of hydrodynamic aspects of heater design and operating experience with particular emphasis on the problem of drainage. Formulae are derived and presented with recommendations for their use by designers in the power plant industry. (author)

  4. THE ROLE OF DUCKWEED (LEMNA MINOR L.) IN SECONDARY CLARIFIER TANKS

    OpenAIRE

    Engin Gürtekin; Nusret Şekerdağ

    2008-01-01

    In this study, the effects of duckweed (Lemna minor L.) presence on the effluent water quality and settling characteristics in the secondary clarifier tank of a conventional biological treatment plant were investigated. For this purpose, the performances of the secondary clarifier with and without duckweed were compared. In the secondary clarifier tank with duckweed, COD, BOD5, ammonium and phosphate removal efficiencies were higher by 15, 25, 35 and 45%, respectively. SS concentration of eff...

  5. Blending Of Radioactive Salt Solutions In Million Gallon Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Leishear, Robert A.; Lee, Si Y.; Fowley, Mark D.; Poirier, Michael R.

    2012-12-10

    Research was completed at Savannah River National Laboratory (SRNL) to investigate processes related to the blending of radioactive, liquid waste, salt solutions in 4920 cubic meter, 25.9 meter diameter storage tanks. One process was the blending of large salt solution batches (up to 1135 ? 3028 cubic meters), using submerged centrifugal pumps. A second process was the disturbance of a settled layer of solids, or sludge, on the tank bottom. And a third investigated process was the settling rate of sludge solids if suspended into slurries by the blending pump. To investigate these processes, experiments, CFD models (computational fluid dynamics), and theory were applied. Experiments were performed using simulated, non-radioactive, salt solutions referred to as supernates, and a layer of settled solids referred to as sludge. Blending experiments were performed in a 2.44 meter diameter pilot scale tank, and flow rate measurements and settling tests were performed at both pilot scale and full scale. A summary of the research is presented here to demonstrate the adage that, ?One good experiment fixes a lot of good theory?. Experimental testing was required to benchmark CFD models, or the models would have been incorrectly used. In fact, CFD safety factors were established by this research to predict full-scale blending performance. CFD models were used to determine pump design requirements, predict blending times, and cut costs several million dollars by reducing the number of required blending pumps. This research contributed to DOE missions to permanently close the remaining 47 of 51 SRS waste storage tanks.

  6. Effective pine bark composting with the Dome Aeration Technology

    International Nuclear Information System (INIS)

    In South Africa garden refuse is primarily disposed of in domestic landfills. Due to the large quantities generated, any form of treatment would be beneficial for volume reduction, waste stabilization and resource recovery. Dome Aeration Technology (DAT) is an advanced process for aerobic biological degradation of garden refuse and general waste [Paar, S., Brummack, J., Gemende, B., 1999a. Advantages of dome aeration in mechanical-biological waste treatment. In: Proceedings of the 7th International Waste Management and Landfill Symposium, Cagliari, 4-8 October 1999; Paar, S., Brummack, J., Gemende, B., 1999b. Mechanical-biological waste stabilization by the dome aeration method. Environment Protection Engineering 25 (3/99). Mollekopf, N., Brummack, J., Paar, S., Vorster, K., 2002. Use of the Dome Aeration Technology for biochemical stabilization of waste prior to landfilling. In: Proceedings of the Wastecon 2002, Waste Congress and Exhibition, Durban, South Africa.]. It is a non-reactor open windrow composting process, with the main advantage being that the input material needs no periodic turning. A rotting time of only 3-4 months indicates the high efficiency. Additionally, the low capital/operational costs, low energy inputs and limited plant requirements provide potential for use in aerobic refuse stabilization. The innovation in the DAT process is the passive aeration achieved by thermally driven advection through open windrows caused by temperature differences between the degrading material and the outside environment. This paper investigates the application of Dome Aeration Technology to pine bark composting as part of an integrated waste management strategy. A full-scale field experiment was performed at the Bisasar Road Landfill Site in Durban to assess the influence of climate, waste composition and operational conditions on the process. A test windrow was constructed and measurements of temperature and airflow through the material were taken. The process

  7. AX Tank Farm tank removal study

    International Nuclear Information System (INIS)

    This report considers the feasibility of exposing, demolishing, and removing underground storage tanks from the 241-AX Tank Farm at the Hanford Site. For the study, it was assumed that the tanks would each contain 360 ft3 of residual waste (corresponding to the one percent residual Inventory target cited in the Tri-Party Agreement) at the time of demolition. The 241-AX Tank Farm is being employed as a ''strawman'' in engineering studies evaluating clean and landfill closure options for Hanford single-shell tank farms. The report is one of several reports being prepared for use by the Hanford Tanks Initiative Project to explore potential closure options and to develop retrieval performance evaluation criteria for tank farms

  8. AX Tank Farm tank removal study

    Energy Technology Data Exchange (ETDEWEB)

    SKELLY, W.A.

    1998-10-14

    This report considers the feasibility of exposing, demolishing, and removing underground storage tanks from the 241-AX Tank Farm at the Hanford Site. For the study, it was assumed that the tanks would each contain 360 ft{sup 3} of residual waste (corresponding to the one percent residual Inventory target cited in the Tri-Party Agreement) at the time of demolition. The 241-AX Tank Farm is being employed as a ''strawman'' in engineering studies evaluating clean and landfill closure options for Hanford single-shell tank farms. The report is one of several reports being prepared for use by the Hanford Tanks Initiative Project to explore potential closure options and to develop retrieval performance evaluation criteria for tank farms.

  9. Settling the Complexity of Computing Two-Player Nash Equilibria

    OpenAIRE

    Chen, Xi; Deng, Xiaotie; Teng, Shang-Hua

    2007-01-01

    We settle a long-standing open question in algorithmic game theory. We prove that Bimatrix, the problem of finding a Nash equilibrium in a two-player game, is complete for the complexity class PPAD Polynomial Parity Argument, Directed version) introduced by Papadimitriou in 1991. This is the first of a series of results concerning the complexity of Nash equilibria. In particular, we prove the following theorems: Bimatrix does not have a fully polynomial-time approximation scheme unless every ...

  10. Settling accretion onto slowly rotating X-ray pulsars

    OpenAIRE

    Shakura, N. I.; Postnov, K. A.; Kochetkova, A. Yu.; Hjalmarsdotter, L.

    2013-01-01

    Quasi-spherical subsonic accretion onto slowly rotating magnetized NS is considered, when the accreting matter settles down subsonically onto the rotating magnetosphere, forming an extended quasi-static shell. The shell mediates the angular momentum transfer to/from the rotating NS magnetosphere by large-scale convective motions, which lead to an almost iso-angular-momentum rotation law inside the shell. The accretion rate through the shell is determined by the ability of the plasma to enter ...

  11. The nature of particulate organic matter settled on solid substrata

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, M.O.; Wagh, A.B.

    National Institute of Oceanography, Dona Paula, Goa, 403004, India. Received 25/0 I/90, in revised form 16/02/90, accepted 22/03/90. Particulate material settled on aluminium and glass panels during their immersion in estuarine water was analysed... etre principale ment d'origine hactcrienne. Oceollo!ogica Acta, 1990, 13.4,471-474. INTRODUCTION Solid substrata placed in an aquatic environment adsorb organic molecules from the ambient waters onto their surfaces, making them readily available...

  12. Radium-226 removal by precipitation and sedimentation in settling ponds

    International Nuclear Information System (INIS)

    A recent pilot plant program carried out at Rio Algom's Quirke uranium mine at Elliot Lake, Ontario, is described. The goal was the production of tailings basin effluents which were low in total radium 226. The process tested involved precipitation of radium with barium chloride and sedimentation in plastic-lined settling ponds. Adjustment of the tailings basin overflow from its normal value of pH 9.5 by addition of sulphuric acid to about pH 7.5 was found to give approximately a five-fold improvement in total radium 226 removal. A five-month demonstration test resulted in an effluent with a mean total radium 226 activity of 44 pCi/l after 2.5 days settling time and 29 pCi/l after five days. The results are used to propose a schedule of achievable total radium 226 activities where precipitation and sedimentation are employed. The maximum suggested values after five days nominal settling time are: 30 pCi/l in an annual mean, 60 pCi/l in a monthly mean, 60 pCi/l in a weekly mean, and 80 pCi/l in any single grab sample. (auth)

  13. Radon removal from water supplies by diffused bubble aeration system

    International Nuclear Information System (INIS)

    The removal efficiency of moderate levels of radon from groundwater supplies was evaluated using the diffused bubble aeration technique. An aeration system was designed, constructed and operated for that purpose. The effect of air-to-water ratio and detention time on radon removal were evaluated through 32 runs. The possibility to reduce the radon activity in the influent stream to the U.S. Environmental Protection Agency proposed maximum contaminant level (MCL) was verified through many alternative combined values of both air-to-water ratios and detention times. The results showed that at detention time of 19 minutes and air-to-water ratio of 12, the average radon removal is about 97%. The stripping constant characterizing this system was calculated and the removal efficiency at extended values of detention time was predicted. The data obtained are site specific, being dependent on container size, type of diffusers, temperature, and influent radon radioactivity. (author)

  14. Feasibility of biological aerated filters (BAFs) for treating landfill leachate.

    OpenAIRE

    Stephenson, Tom; Pollard, Simon J. T.; Cartmell, Elise

    2004-01-01

    Ammonia can be removed from landfill leachate through aerobic biological processes. The biological aerated filter (BAF) combines biological treatment and subsequent biomass separation in one reactor providing a small footprint alternative to conventional systems. Leachate from an operational landfill was found to be aerobically treatable using the OECD recommended Modified Zahn- Wellens test. This leachate was used as feed to a pilot-scale BAF at influent COD and ammoniacal-...

  15. Landfill aeration for emission control before and during landfill mining.

    Science.gov (United States)

    Raga, Roberto; Cossu, Raffaello; Heerenklage, Joern; Pivato, Alberto; Ritzkowski, Marco

    2015-12-01

    The landfill of Modena, in northern Italy, is now crossed by the new high velocity railway line connecting Milan and Bologna. Waste was completely removed from a part of the landfill and a trench for the train line was built. With the aim of facilitating excavation and further disposal of the material extracted, suitable measures were defined. In order to prevent undesired emissions into the excavation area, the aerobic in situ stabilisation by means of the Airflow technology took place before and during the Landfill Mining. Specific project features involved the pneumatic leachate extraction from the aeration wells (to keep the leachate table low inside the landfill and increase the volume of waste available for air migration) and the controlled moisture addition into a limited zone, for a preliminary evaluation of the effects on process enhancement. Waste and leachate were periodically sampled in the landfill during the aeration before the excavation, for quality assessment over time; the evolution of biogas composition in the landfill body and in the extraction system for different plant set-ups during the project was monitored, with specific focus on uncontrolled migration into the excavation area. Waste biological stability significantly increased during the aeration (waste respiration index dropped to 33% of the initial value after six months). Leachate head decreased from 4 to 1.5m; leachate recirculation tests proved the beneficial effects of moisture addition on temperature control, without hampering waste aerobization. Proper management of the aeration plant enabled the minimization of uncontrolled biogas emissions into the excavation area. PMID:26445364

  16. Modeling of damage due to shrinkage in autoclaved aerated concrete

    OpenAIRE

    Koudelka, T.; Kruis, J.; Sysala, S.; M. Vokáč

    2015-01-01

    The paper deals with numerical modeling of damage evolution in autoclaved aerated concrete (AAC) due to shrinkage. It represents coupled thermo-hydro-mechanical problem where the temperature and moisture transports are fully coupled. The mechanical problem is partially coupled with transport part because the AAC shrinkage is influenced by moisture evolution. These models were implemented to the SIFEL software package and they were used for numerical simulation of drying wall made from AAC blo...

  17. Tank 241-C-103 tank characterization plan

    International Nuclear Information System (INIS)

    The data quality objective (DQO) process was chosen as a tool to be used to identify the sampling analytical needs for the resolution of safety issues. A Tank Characterization Plant (TCP) will be developed for each double shell tank (DST) and single-shell tank (SST) using the DQO process. There are four Watch list tank classifications (ferrocyanide, organic salts, hydrogen/flammable gas, and high heat load). These classifications cover the six safety issues related to public and worker health that have been associated with the Hanford Site underground storage tanks. These safety issues are as follows: ferrocyanide, flammable gas, organic, criticality, high heat, and vapor safety issues. Tank C-103 is one of the twenty tanks currently on the Organic Salts Watch List. This TCP will identify characterization objectives pertaining to sample collection, hot cell sample isolation, and laboratory analytical evaluation and reporting requirements in accordance with the appropriate DQO documents. In addition, the current contents and status of the tank are projected from historical information. The relevant safety issues that are of concern for tanks on the Organic Salts Watch List are: the potential for an exothermic reaction occurring from the flammable mixture of organic materials and nitrate/nitrite salts that could result in a release of radioactive material and the possibility that other safety issues may exist for the tank

  18. Tank 241-AW-101 tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Sathyanarayana, P.

    1994-11-22

    The first section gives a summary of the available information for Tank AW-101. Included in the discussion are the process history and recent sampling events for the tank, as well as general information about the tank such as its age and the risers to be used for sampling. Tank 241-AW-101 is one of the 25 tanks on the Flammable Gas Watch List. To resolve the Flammable Gas safety issue, characterization of the tanks, including intrusive tank sampling, must be performed. Prior to sampling, however, the potential for the following scenarios must be evaluated: the potential for ignition of flammable gases such as hydrogen-air and/or hydrogen-nitrous oxide; and the potential for secondary ignition of organic-nitrate/nitrate mixtures in crust layer initiated by the burning of flammable gases or by a mechanical in-tank energy source. The characterization effort applicable to this Tank Characterization Plan is focused on the resolution of the crust burn flammable gas safety issue of Tank AW-101. To evaluate the potential for a crust burn of the waste material, calorimetry tests will be performed on the waste. Differential Scanning Calorimetry (DSC) will be used to determine whether an exothermic reaction exists.

  19. Tank 241-AW-101 tank characterization plan

    International Nuclear Information System (INIS)

    The first section gives a summary of the available information for Tank AW-101. Included in the discussion are the process history and recent sampling events for the tank, as well as general information about the tank such as its age and the risers to be used for sampling. Tank 241-AW-101 is one of the 25 tanks on the Flammable Gas Watch List. To resolve the Flammable Gas safety issue, characterization of the tanks, including intrusive tank sampling, must be performed. Prior to sampling, however, the potential for the following scenarios must be evaluated: the potential for ignition of flammable gases such as hydrogen-air and/or hydrogen-nitrous oxide; and the potential for secondary ignition of organic-nitrate/nitrate mixtures in crust layer initiated by the burning of flammable gases or by a mechanical in-tank energy source. The characterization effort applicable to this Tank Characterization Plan is focused on the resolution of the crust burn flammable gas safety issue of Tank AW-101. To evaluate the potential for a crust burn of the waste material, calorimetry tests will be performed on the waste. Differential Scanning Calorimetry (DSC) will be used to determine whether an exothermic reaction exists

  20. Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits.

    Science.gov (United States)

    Ozkan, Fahri; Tuna, M Cihat; Baylar, Ahmet; Ozturk, Mualla

    2014-01-01

    Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number. PMID:25225935

  1. In situ nitrogen removal from leachate by bioreactor landfill with limited aeration

    International Nuclear Information System (INIS)

    The feasibility of simultaneous nitrification and denitrification in a bioreactor landfill with limited aeration was assessed. Three column reactors, simulating bioreactor landfill operations under anaerobic condition (as reference), intermittent forced aeration and enhanced natural aeration were hence established, where aerated columns passed through two phases, i.e., fresh landfill and well-decomposed landfill. The experimental results show that limited aeration decreased nitrogen loadings of leachate distinctly in the fresh landfill. In the well-decomposed landfill, the NH4+-N of the input leachate could be nitrified completely in the aerated landfill columns. The nitrifying loadings of the column cross section reached 7.9 g N/m2 d and 16.9 g N/m2 d in the simulated landfill columns of intermittent forced aeration and enhanced natural aeration, respectively. The denitrification was influenced by oxygen distribution in the landfill column. Intermittent existence of oxygen in the landfill with the intermittent forced aeration was favorable to denitrify the NO2--N and NO3--N, indicated by the high denitrification efficiency (>99%) under the condition of BOD5/TN of more than 5.4 in leachate; locally persistent existence of oxygen in the landfill with enhanced natural aeration could limit the denitrification, indicated by relatively low denitrification efficiency of about 75% even when the BOD5/TN in leachate had an average of 7.1

  2. Modelling, Optimization and Optimal Control of Small Scale Stirred Tank Bioreactors

    OpenAIRE

    Mitko Petrov; Uldis Viesturs; Stoyan Tzonkov; Tatjana Ilkova

    2004-01-01

    Models of the mass-transfer in a stirred tank bioreactor depending on general indexes of the processes of aeration and mixing in concrete simplifications of the hydrodynamic structure of the flows are developed. The offered combined model after parameters identification is used for optimization of the parameters of the apparatus construction. The optimization problem is solved by using of the fuzzy sets theory and in this way the unspecified as a result of the model simplification are read. I...

  3. Theoretical comparison between solar combisystems based on bikini tanks and tank-in-tank solar combisystems

    DEFF Research Database (Denmark)

    Yazdanshenas, Eshagh; Furbo, Simon; Bales, Chris

    2008-01-01

    Theoretical investigations have shown that solar combisystems based on bikini tanks for low energy houses perform better than solar domestic hot water systems based on mantle tanks. Tank-in-tank solar combisystems are also attractive from a thermal performance point of view. In this paper......, theoretical comparisons between solar combisystems based on bikini tanks and tank-in-tank solar combisystems are presented....

  4. Comparative hydraulics of two fishery research circular tanks and recommendations for control of experimental bias

    Science.gov (United States)

    Odeh, M.; Schrock, R.M.; Gannam, A.

    2003-01-01

    Hydraulic characteristics inside two research circular tanks (1.5-m and 1.2-m diameter) with the same volume of water were studied to understand how they might affect experimental bias by influencing the behavior and development of juvenile fish. Water velocities inside each tank were documented extensively and flow behavior studied. Surface inflow to the 1.5-m tank created a highly turbulent and aerated surface, and produced unevenly distributed velocities within the tank. A low-flow velocity, or "dead" zone, persisted just upstream of the surface inflow. A single submerged nozzle in the 1.2-m tank created uniform flow and did not cause undue turbulence or introduce air. Flow behavior in the 1.5-m tank is believed to have negatively affected the feeding behavior and physiological development of a group of juvenile fall chinook salmon, Oncorhynchus tshawytscha. A new inflow nozzle design provided comparable flow behavior regardless of tank size and water depth. Maintaining similar hydraulic conditions inside tanks used for various biological purposes, including fish research, would minimize experimental bias caused by differences in flow behavior. Other sources of experimental bias are discussed and recommendations given for reporting and control of experimental conditions in fishery research tank experiments.

  5. 16 CFR 1209.4 - Test procedures for determining settled density.

    Science.gov (United States)

    2010-01-01

    ... density. 1209.4 Section 1209.4 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT... procedures for determining settled density. The settled density of lose fill insulation must be determined.... This section describes the procedure for determining the settled density of loose fill insulation....

  6. Tank characterization report: Tank 241-C-109

    International Nuclear Information System (INIS)

    Single-shell tank 241-C-109 is a Hanford Site Ferrocyanide Watch List tank that was most recently sampled in September 1992. Analyses of materials obtained from tank 241-C-109 were conducted to support the resolution of the ferrocyanide unreviewed safety question (USQ) and to support Hanford Federal Facility Agreement and consent Order (Tri- Party Agreement) Milestone M-10-00. This report describes this analysis

  7. Tank characterization report: Tank 241-C-109

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, B.C.; Borshiem, G.L.; Jensen, L.

    1993-09-01

    Single-shell tank 241-C-109 is a Hanford Site Ferrocyanide Watch List tank that was most recently sampled in September 1992. Analyses of materials obtained from tank 241-C-109 were conducted to support the resolution of the ferrocyanide unreviewed safety question (USQ) and to support Hanford Federal Facility Agreement and consent Order (Tri- Party Agreement) Milestone M-10-00. This report describes this analysis.

  8. TANK 50 BATCH 0 SALTSTONE FORMULATION CONFIRMATION

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C.

    2006-06-05

    Savannah River National Laboratory (SRNL) personnel were requested to confirm the Tank 50 Batch 0 grout formulation per Technical Task Request, SSF-TTR-2006-0001 (task 1 of 2) [1]. Earlier Batch 0 formulation testing used a Tank 50 sample collected in September 2005 and is described elsewhere [2]. The current testing was performed using a sample of Tank 50 waste collected in May 2006. This work was performed according to the Technical Task and Quality Assurance Plan (TT/QAP), WSRC-RP-2006-00594 [3]. The salt solution collected from Tank 50 in May 2006 contained approximately 3 weight percent more solids than the sample collected in September 2005. The insoluble solids took longer to settle in the new sample which was interpreted as indicating finer particles in the current sample. The saltstone formulation developed for the September 2005 Tank 50 Batch 0 sample was confirmed for the May 2006 sample with one minor exception. Saltstone prepared with the Tank 50 sample collected in May 2006 required 1.5 times more Daratard 17 set retarding admixture than the saltstone prepared with the September In addition, a sample prepared with lower shear mixing (stirring with a spatula) had a higher plastic viscosity (57 cP) than samples made with higher shear mixing in a blender (23cP). The static gel times of the saltstone slurries made with low shear mixing were also shorter ({approx}32 minutes) than those for comparable samples made in the blender ({approx}47 minutes). The addition of the various waste streams (ETP, HEU-HCAN, and GPE-HCAN) to Tank 50 from September 2005 to May 2006 has increased the amount of set retarder, Daratard 17, required for processing saltstone slurries through the Saltstone facility. If these streams are continued to be added to Tank 50, the quantity of admixtures required to maintain the same processing conditions for the Saltstone facility will probably change and additional testing is recommended to reconfirm the Tank 50 Saltstone formulation.

  9. TANK 50 BATCH 0 SALTSTONE FORMULATION CONFIRMATION

    International Nuclear Information System (INIS)

    Savannah River National Laboratory (SRNL) personnel were requested to confirm the Tank 50 Batch 0 grout formulation per Technical Task Request, SSF-TTR-2006-0001 (task 1 of 2) [1]. Earlier Batch 0 formulation testing used a Tank 50 sample collected in September 2005 and is described elsewhere [2]. The current testing was performed using a sample of Tank 50 waste collected in May 2006. This work was performed according to the Technical Task and Quality Assurance Plan (TT/QAP), WSRC-RP-2006-00594 [3]. The salt solution collected from Tank 50 in May 2006 contained approximately 3 weight percent more solids than the sample collected in September 2005. The insoluble solids took longer to settle in the new sample which was interpreted as indicating finer particles in the current sample. The saltstone formulation developed for the September 2005 Tank 50 Batch 0 sample was confirmed for the May 2006 sample with one minor exception. Saltstone prepared with the Tank 50 sample collected in May 2006 required 1.5 times more Daratard 17 set retarding admixture than the saltstone prepared with the September In addition, a sample prepared with lower shear mixing (stirring with a spatula) had a higher plastic viscosity (57 cP) than samples made with higher shear mixing in a blender (23cP). The static gel times of the saltstone slurries made with low shear mixing were also shorter (∼32 minutes) than those for comparable samples made in the blender (∼47 minutes). The addition of the various waste streams (ETP, HEU-HCAN, and GPE-HCAN) to Tank 50 from September 2005 to May 2006 has increased the amount of set retarder, Daratard 17, required for processing saltstone slurries through the Saltstone facility. If these streams are continued to be added to Tank 50, the quantity of admixtures required to maintain the same processing conditions for the Saltstone facility will probably change and additional testing is recommended to reconfirm the Tank 50 Saltstone formulation

  10. 涌浪机标准参数研究%Research on the standard parameters of wave aerator

    Institute of Scientific and Technical Information of China (English)

    王玮; 韩梦遐

    2014-01-01

    由于养殖池塘水体受温度、气压、光合作用、盐度、养殖鱼类等多种因素影响而不断发生变化,使涌浪机的质量较难定量分析。为了制定切实可行的涌浪机行业标准,开展了涌浪机标准参数的研究。试验参考了SC/T 6009《增氧机增氧能力试验方法》的标准检测程序,利用实验室直径8.0 m的标准水池作为试验平台,试验水温20℃,气压101.325 kPa,初始溶氧浓度为0 mg/L,试验用水为自来水,对3种涌浪机进行对比试验研究。结果表明:净浮力、绝缘电阻等基本参数用增氧机标准评判仍然可行;空载噪声、增氧能力、动力效率等参数变化较大;宜增加提水能力和造浪强度参数,以适应对涌浪机的评判。%It is difficult to quantitatively analyze the performance of wave aerator, due to the fact that the water in culture pond constantly changes with various factors such as temperature, air pressure, photosynthesis, salinity and farmed species, etc. we carried out the research on the standard parameters of wave aerator in order to develop its practical and feasible industry standard. Using the eight-meter diameter laboratory standard tank as a testing platform, the experiment was conducted at 20 ℃ water temperature, 101. 325 kPa air pressure, and 0 mg/L initial concentration of dissolved oxygen, by reference to the standard testing procedure described in the "SC/T 6009-1999 Test methods of oxygen-enriched capacity for aerator". The comparative experiment was done for three types of wave aerators in clean water. The experiment results showed that it was still feasible to judge the basic parameters such as net buoyancy rate and insulation resistivity by using the criteria of aerator; and the other parameters such as no-load noise, oxygen transfer capacity and power efficiency changed greatly;the parameter values of water-lifting capacity and wave-generating intensity should be increased to

  11. Tank 241-B-101 tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, R.D. [Westinghouse Hanford Co., Richland, WA (United States)

    1995-04-28

    The Defense Nuclear Facilities Safety Board (DNFSB) has advised the US Department of Energy (DOE) to concentrate the near-term sampling and analysis activities on identification and resolution of safety issues (Conway 1993). The data quality objective (DQO) process was chosen as a tool to be used to identify the sampling and analytical needs for the resolution of safety issues. As a result, a revision in the Federal Facility Agreement and Consent Order (Tri-Party Agreement or TPA) milestone M-44 has been made, which states that ``A Tank Characterization Plan (TCP) will be developed for each double-shell tank (DST) and single-shell tank (SST) using the DQO process``. This document satisfies that requirement for tank 241-B-101 (B-101) sampling activities. Tank B-101 is identified as a low-heat load non-Watch List tank, and is classified as an assumed leaker. The tank is passively ventilated, interim stabilized, and intrusion prevention measures have been completed. As of January 31, 1995, approximately 428,000 liters of non-complexed waste was contained in the tank. Tank B-101 is expected to have two primary layers. A layer of saltcake waste generated from the 242-B evaporator, followed by a top layer of sludge composed of B-Plant high-level, B-Plant low-level, and unknown waste.

  12. Tank 244A tank characterization plan

    International Nuclear Information System (INIS)

    The Double-Shell Tank (DST) System currently receives waste from the Single-Shell Tank (SST) System in support of SST stabilization efforts or from other on-site facilities which generate or store waste. Waste is also transferred between individual DSTs. The mixing or commingling of potentially incompatible waste types at the Hanford Site must be addressed prior to any waste transfers into the DSTs. The primary goal of the Waste Compatibility Program is to prevent the formation of an Unreviewed Safety Question (USQ) as a result of improper waste management. Tank 244A is a Double Contained Receiver Tank (DCRT) which serves as any overflow tank for the East Area Farms. Waste material is able to flow freely between the underground storage tanks and tank 244A. Therefore, it is necessary to test the waste in tank 244A for compatibility purposes. Two issues related to the overall problem of waste compatibility must be evaluated: Assurance of continued operability during waste transfer and waste concentration and Assurance that safety problems are not created as a result of commingling wastes under interim storage. The results of the grab sampling activity prescribed by this Tank Characterization Plan shall help determine the potential for four kinds of safety problems: criticality, flammable gas accumulation, energetics, and corrosion and leakage

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  14. Transferência de massa em sistemas de aeração por jatos bifásicos Mass transfer in two-phase jet aeration systems

    Directory of Open Access Journals (Sweden)

    Iran Eduardo Lima Neto

    2013-03-01

    Full Text Available A injeção de misturas de ar e água na forma de jatos bifásicos é bastante usada para a aeração artificial em tanques e corpos hídricos. No presente trabalho, foram realizados experimentos para investigar a transferência de massa induzida por estes jatos em um tanque de aeração. Os resultados forneceram eficiências de transferência de oxigênio padrão variando entre aproximadamente 5 e 9%. Combinando-se os dados obtidos nesta pesquisa com os disponíveis na literatura, foram geradas correlações adimensionais para o coeficiente de transferência de massa em função da fração volumétrica de ar e do número de Froude densimétrico. Finalmente, os resultados foram aplicados a situações práticas envolvendo sistemas de aeração por jatos bifásicos.The injection of air-water mixtures through two-phase jets is widely used for artificial aeration in tanks and water bodies. In this study, experiments were conducted to investigate mass transfer induced by such jets in an aeration tank. The results provided standard oxygen transfer efficiencies ranging from about 5 to 9%. Combining the results obtained here with those from previous investigations allowed to generate dimensionless correlations for the mass transfer coefficient as a function of the gas volume fraction and the densimetric Froude number. Finally, the results were applied to practical situations involving two-phase jet aeration systems.

  15. Modeling of Spinel Settling in Waste Glass Melter

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel R.; Nemec, Lubomir; Schill, Petr

    1999-06-01

    Each 1% increase of waste loading (W), defined as the high-level waste (HLW) mass fraction in glass, can save the U.S. Department of Energy (DOE) over a half billion U.S. dollars for vitrification and disposal. For a majority of Hanford and Savannah River waste streams, W is limited by spinel precipitation and settling in waste glass melters. Therefore, a fundamental understanding of spinel behavior is crucial for economy and the low-risk operation of HLW vitrification. The goal of this research is to develop a basic understanding of the dynamics of spinel formation and motion in velocity, temperature, and redox fields that are characteristic for the glass-melting process. This goal is being achieved by directly studying spinel formation and settling in molten glass and by developing a mathematical tool for predicting the spinel behavior and accumulation rate in the melter. The main potential benefit of this study is achieving a lower waste-glass volume, which translates into a shorter cleanup time, a smaller processing facility, a smaller repository space, and, hence, a reduced investment of time and money to reach acceptable technical risks. Additional benefits include (1) more accurately assessing sensible limits for problem constituents (such as chromium) in the melter feed, (2) reducing the blending requirements, and (3) comparing cost and risk with other options (pretreatment, blending or diluting the waste) to determine the best path forward. The results of this study will allow alternate melter designs and operating conditions to be evaluated. The study will also address the option of removing the settled sludge from the melter.

  16. Decontamination technology of contaminated water with flocculating and settling technology

    International Nuclear Information System (INIS)

    In the joint research and development of treatment systems of cooling water for cutting asphalt pavement surface with our authors' group, the liquid-solid separation technology by flocculating and settling technology, and the flocculants for the use of systems were developed. In this paper, the developed flocculating and settling technology and the flocculants are discussed first. Next, the demonstration tests of decontamination technology on the contaminated water in swimming pools in an elementary school located at Motomiya City, Fukushima Prefecture had been conducted by use of the stationary purification system of contaminated water and the flocculants compounding with or without iron ferrocianide developed by the preliminary test. It was clarified from the results that ionized cesium (Cs) rarely exists in the stagnant water in pools, ponds, lakes and so on at the time when nine months have passed since Fukushima Dai-ichi nuclear power plant accidents. Further, it is necessary to use the flocculants compounding iron ferrocianide in the case where ionized Cs exists in water. From the above-mentioned results, the following problems were pointed out: One problem was cyanide dissolution in the purified water and the other one was the dissolution from the dehydration sludge. Finally, the high-performance mobile purification units of contaminated water which is capable for carrying with trucks have been developed, and the demonstration test was performed in Minami-soma City, Fukushima Prefecture to purify the contaminated water in a pond and generated by the high-pressure water washing in a Public Hall. From the test results, it was made clear that the dehydration sludge separated by liquid-solid settling of the contaminated water of around 1,000Bq/l became a high radiation dose of about 185,000Bq/l. (author)

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

    Science.gov (United States)

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

    2015-12-01

    Given that few studies investigated the effects of aeration position (AP) on the performance of aerated constructed wetlands, the aim of this study was to evaluate the effects of AP on organics, nitrogen and phosphorus removal in lab-scale combined oxidation pond-constructed wetland (OP-CW) systems. Results showed that middle aeration allowed the CW to possess more uniform oxygen distribution and to achieve greater removals of COD and NH3-N, while the CW under bottom aeration and surface aeration demonstrated more distinct stratification of oxygen distribution and surface aeration brought about better TN removal capacity for the OP-CW system. However, no significant influence of artificial aeration or AP on TP removal was observed. Overall, AP could significantly affect the spatial distribution of dissolved oxygen by influencing the oxygen diffusion paths in aerated CWs, thereby influencing the removal of pollutants, especially organics and nitrogen, which offers a reference for the design of aerated CWs. PMID:26360599

  18. Modeling of mixing for stirred bioreactors: 3. Mixing time for aerated simulated broths

    OpenAIRE

    Cascaval Dan; Oniscu Corneliu; Galaction Anca-Irina; Ungureanu Fiorina

    2002-01-01

    This paper presents the experiments on mixing efficiency for aerated media for a laboratory stirred bioreactor with a double turbine impeller. The effects of stirrer rotation speed, air volumetric flow rate and stirrer position on the shaft on mixing time for aerated water and simulated broths (CMCNa solutions) were analyzed. Compared to non-aerated broths, the results indicated that the variation of mixing time with the considered parameters is very different, due to the complex flow mechani...

  19. The Influence of Micropore Oxygen Aeration on the Pond Water Quality Environment

    OpenAIRE

    Xiao-Jiang Chen; Yun-Gan Zhu; Zi-Ming Zhao

    2013-01-01

    In order to know the effects of micropore oxygen aeration on the water quality and economic output, take each 3 of micropore oxygen aeration (experimental pond) and impeller oxygenation (control pond) to make the comparison, indexs of two different aeration methods water were detected from May, 2012 to October, 2012. Such as water temperature, dissolved oxygen, ammonia nitrogen and nitrite, phytoplankton, chemical oxygen demand (CODMn). Results showed that, (1) the indexes of the dissolved ox...

  20. Aeration for fouling control in Submerged Membrane Bioreactors for wastewater treatment: shear simulation and experimental validations

    OpenAIRE

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

    2012-01-01

    Aeration for fouling prevention in SMBRs represents a great part of energy consumption of the process. To decrease it a better understanding of the impact of aeration on filtration performances is required. In spite of its beneficial effect (shear stress on membrane surface, turbulences...), the aeration has an impact on a potential destructuration of mixed liquor that could be detrimental to filtration. Our study aims at estimating this impact for SADm and SADp close to those used in full sc...

  1. Municipal wastewater treatment plant aeration systems and their comparison at WWTP Ljutomer and Murska Sobota

    OpenAIRE

    Kolbl, Sabina

    2009-01-01

    Graduation thesis discusses aeration systems at wastewater treatment plants (WWTP), and compares the operation of the WWTPs at Ljutomer and Murska Sobota. The first four chapters cover the theoretical fundamentals of WWTP aeration and aeration systems. In the introductory section of thesis, the biological treatment of wastewater and its basic processes are briefly discussed. According to the DVWK-ATV-A 131E standards, fundamental equations are discussed for both the rate of consumption and th...

  2. Influence of aeration intensity and medium acidity on phosphate mobilization affected by soil bacteria

    OpenAIRE

    K. V. Lavrentyeva; P. I. Kharchenko; N. V. Cherevach; A. I. Vinnikov

    2009-01-01

    The paper deals with the investigation of phosphate solubilisation conducted by two bacteria Pseudomonas putida and Enterobacter dissolvens under conditions of different rates of aeration and рН. Bacterial development was characterized by different media acidity and aeration levels. It was established optimal aeration rates and potential of hydrogen for soil bacteria growth and phosphate solubilisation – 0.5721 mole О2/l per hour and pH ≈ 6.0.

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

    OpenAIRE

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

    2009-01-01

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

  4. Characteristics of aeration properties of selected soil profiles from central europe

    OpenAIRE

    Brzezińska M.; Włodarczyk T.; Stępniewska Z.; Stępniewski W.; Gliński J.

    2000-01-01

    The purpose of this paper was to characterise soil structure from the point of view of its aeration properties and to verify applicability of some methods for the determination of different properties related to aeration. The studies were performed on 15 representative soil samples from Austria, Czech Republic, Hungary, Poland and Slovakia. The paper presents results of measurements of different soil aeration properties such as oxygen diffusion rate (ODR), redox potential (Eh), relative gas d...

  5. Redox potential driven aeration during very-high-gravity ethanol fermentation by using flocculating yeast

    OpenAIRE

    Liu, Chen-Guang; Hao, Xue-Mi; Lin, Yen-Han; Bai, Feng-Wu

    2016-01-01

    Ethanol fermentation requires oxygen to maintain high biomass and cell viability, especially under very-high-gravity (VHG) condition. In this work, fermentation redox potential (ORP) was applied to drive the aeration process at low dissolved oxygen (DO) levels, which is infeasible to be regulated by a DO sensor. The performance and characteristics of flocculating yeast grown under 300 and 260 g glucose/L conditions were subjected to various aeration strategies including: no aeration; controll...

  6. Low-cost/low-technology aeration techniques for removing radon from drinking water. Environmental research brief

    International Nuclear Information System (INIS)

    Simple treatment techniques designed as low-cost/low-technology aeration techniques were investigated as to determine their effectiveness for the removal of radon from drinking water. The techniques investigated consisted of flow through storage and minimal aeration in various configurations and were found to be effective in varying degrees for the reduction of radon. These low-cost/low-technology aeration techniques may be easily applied in small communities

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

    OpenAIRE

    Abdel E. Ghaly; Ashley Thistle

    2011-01-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Science.gov (United States)

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

    2013-09-01

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

  10. The impact of the adult blue mussel (Mytilus edulis) population on settling of conspecific larvae

    DEFF Research Database (Denmark)

    Dolmer, Per; Stenalt, Ea

    2010-01-01

    The choice of a mussel bed as a settling locality by conspecific mussel larvae is a trade-off between reduced fitness due to an increased risk of larval predation and post-settling food competition with the filtering adults and the benefit from a reduced post-settling mortality. This reduced post......-settling mortality may be due to a reduced benthic predation in habitats with high complexity. In a field experiment, the larval settling of blue mussels, Mytilus edulis, was recorded on an artificial substrate 0.25, 1 and 2 m above the bottom during six periods in spring 1999. The experiment was conducted at four...

  11. The use of mechanical aeration and its effects on water mass

    Directory of Open Access Journals (Sweden)

    SIPAÚBA-TAVARES L. H.

    1999-01-01

    Full Text Available Due to the increasing use of artificial aerators in fish ponds, and to the lack of studies on this subject, this work studied some of the aspects associated with their use. The influence of a diffuser type aerator (AR 120 on the biotic and abiotic variables was evaluated in a fish pond. Three points of the pond were marked for the taking of samples: 5, 10 and 23 m from the aerator. Samples were taken every day for 15 consecutive days: 5 days before the use of the aerator, 5 days with the aerator functioning and 5 days with it not functioning. The limnological variables studied did not show significant differences (P > 0.05 when the three sampling points were compared, but regarding the use of the aerator, variables such as water temperature, transparency, pH, dissolved oxygen, bicarbonate, free CO2, total phosphorus, orthophosphate, ammonia nitrate and nitrite concentrations showed significant differences (P 0.05 with the use of the aerator regarding conductivity, alkalinity, total CO2 and chlorophyll a values. The phytoplanktonic community suffered as a direct influence of the aerator (P < 0.05. The community was dominated by Chlorophyta, representing more than 70% of the total organisms present, followed by Cyanophyta and Chrysophyta which tended to increase in number after the use of the aerator. This probably occurred because these groups adapt quickly to changes in the environment.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-28

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

  13. Microstructure and Properties of Silty Siliceous Crushed Stone-lime Aerated Concrete

    Institute of Scientific and Technical Information of China (English)

    WANG Qiankun; CHEN Youzhi; LI Fangxian; SUN Tao; XU Bingbo

    2006-01-01

    The clayish crushed stone was used for making aerated concrete. Through studying hydro-thermal synthesis reaction, mix ratio, gas-forming and performance analysis, Grade-B05 and Grade-B06 aerated concrete were prepared successfully. The proper mix ratio and key processing parameters were achieved. The microstructure of aerated concrete with crush stone was analyzed by means of XRD and SEM. The experimental results indicate that the hydration products are poorly crystalline C-S-H (B), tobermorite and hydrogarnet. No component of clay was found. Unreacted SiO2 can be in existence, and the structure system of aerated concrete is homogeneous and dense.

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

    International Nuclear Information System (INIS)

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

  15. The Effect of Air Hole Location For Aeration Performance in Circular Conduits

    OpenAIRE

    GÖKGÖZ, akın; GÜNEŞ, Muhammed Cemal; AKKOYUNLU, Yusuf; Ergün, Ömer; Ünsal, Mehmet

    2014-01-01

    Dissolved oxygen in the water is one of the important parameters that indicates water quality. İt is also important for aquatic life in water. Aeration methods used for increase theoxygen amount in waters.The injection of air from the atmosphere into water is called aeration. Hydroulic structures widely used in aeration. İn this study, the effect of air hole location to aeration percformance in circular conduits way investigated. As a result,there is no significant effect of air hole location...

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-15

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

  18. Landfill aeration in the framework of a reclamation project in Northern Italy.

    Science.gov (United States)

    Raga, Roberto; Cossu, Raffaello

    2014-03-01

    In situ aeration by means of the Airflow technology was proposed for landfill conditioning before landfill mining in the framework of a reclamation project in Northern Italy. A 1-year aeration project was carried out on part of the landfill with the objective of evaluating the effectiveness of the Airflow technology for landfill aerobization, the evolution of waste biological stability during aeration and the effects on leachate and biogas quality and emissions. The main outcomes of the 1-year aeration project are presented in the paper. The beneficial effect of the aeration on waste biological stability was clear (63% reduction of the respiration index); however, the effectiveness of aeration on the lower part of the landfill is questionable, due to the limited potential for air migration into the leachate saturated layers. During the 1-year in situ aeration project approx. 275 MgC were discharged from the landfill body with the extracted gas, corresponding to 4.6 gC/kgDM. However, due to the presence of anaerobic niches in the aerated landfill, approx. 46% of this amount was extracted as CH4, which is higher than reported in other aeration projects. The O2 conversion quota was lower than reported in other similar projects, mainly due to the higher air flow rates applied. The results obtained enabled valuable recommendations to be made for the subsequent application of the Airflow technology to the whole landfill. PMID:24411985

  19. Postconstruction report for the mercury tanks interim action at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Voskuil, T.L.

    1993-09-01

    Three underground concrete settling tanks (tanks 2101-U, 2104-U, and 2100-U) at the Y-12 Plant on the Oak Ridge Reservation in Oak Ridge, Tennessee, contained contaminated sludges contributing mercury to the Upper East Fork Poplar Creek (UEFPC). These tanks were cleaned out as an interim action under the Comprehensive Environmental Response, Compensation, and Liability Act as part of the Reduction of Mercury in Plant Effluent subproject. Cleaning out these tanks prevented the sludge that had settled in the bottom from resuspending and carrying mercury into UEFPC. Tanks 2104-U and 2100-U were returned to service and will continue to receive effluent from buildings 9201-4 and 9201-5. Tank 2101-U had been abandoned and its effluent redirected to Tank 2100-U during previous activities. This interim action permanently sealed Tank 2101-U from the storm sewer system. Upon removal of materials and completion of cleanup, inspections determined that the project`s cleanup criteria had been met. The structural integrity of the tanks was also inspected, and minor cracks identified in tanks 2101-U and 2104-U were repaired. This project is considered to have been completed successfully because it met its performance objectives as addressed in the Interim Record of Decision and the work plan: to remove the waste from the three storage tanks; to ensure that the tanks were cleaned to the levels specified; to return tanks 2100-U and 2104-U to service; to isolate Tank 2101-U permanently; and to manage the wastes in an appropriate fashion.

  20. Think tanks in Denmark

    DEFF Research Database (Denmark)

    Ørsten, Mark; Nørgaard Kristensen, Nete

    2016-01-01

    Though think tanks have a long history internationally, they have especially in recent years come to play an increasingly important role in both policy-formulation and public debate. In this article, we analyse the growing presence of think tanks in a Danish context during the 2000s and the first...... half of the 2010s, because in this national setting think tanks are still a relatively new phenomenon. Based on theories of mediatization and de-corporatization, we present 1) an analysis of the visibility of selected Danish think tanks in the media and 2) an analysis of their political networks...... outside the media. The study shows that the two largest and oldest think tanks in Denmark, the liberal think tank CEPOS and the social democratic think tank ECLM, are very active and observable in the media; that the media’s distribution of attention to these think tanks, to some extent, confirms a re...

  1. Tank 241-TY-101 Tank Characterization Plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-TY-101

  2. Tank 241-U-105 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-U-105

  3. Tank 241-U-103 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-U-103

  4. Tank 241-SX-103 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-SX-103

  5. Tank 241-BX-104 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-BX-104

  6. Tank 241-T-107 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-T-107

  7. Tank 241-TY-101 Tank Characterization Plan

    Energy Technology Data Exchange (ETDEWEB)

    Homi, C.S.

    1995-03-20

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-TY-101.

  8. Tank 241-T-111 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-T-111

  9. Tank 241-TX-105 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, WHC 222-S Laboratory, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-TX-105

  10. Settling accretion onto slowly rotating X-ray pulsars

    CERN Document Server

    Shakura, N I; Kochetkova, A Yu; Hjalmarsdotter, L

    2013-01-01

    Quasi-spherical subsonic accretion onto slowly rotating magnetized NS is considered, when the accreting matter settles down subsonically onto the rotating magnetosphere, forming an extended quasi-static shell. The shell mediates the angular momentum transfer to/from the rotating NS magnetosphere by large-scale convective motions, which lead to an almost iso-angular-momentum rotation law inside the shell. The accretion rate through the shell is determined by the ability of the plasma to enter the magnetosphere due to Rayleigh-Taylor instability while taking cooling into account. The settling regime of accretion is possible for moderate X-ray luminosities L <4 10^36 erg/s. At higher luminosities a free-fall gap above the NS magnetosphere appears due to rapid Compton cooling, and accretion becomes highly non-stationary. From observations of spin-up/spin-down rates of wind accreting equilibrium XPSRs with known orbital periods (GX 301-2, Vela X-1), the main dimensionless parameters of the model and be determin...

  11. Tank 49H salt batch supernate qualification for ARP/MCU

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Peters, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fink, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Foster, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2008-08-25

    This report covers the laboratory testing and analyses of Tank 49H Qualification Sample Sets A and C, performed in support of initial radioactive operations of Actinide Removal Process (ARP) and Modular Caustic-Side Solvent Extraction Unit (MCU). Major goals of this work include checking that Tank 49H was well mixed after the last receipt of Tank 23H, characterizing Tank 49H supernate after solids are settled so that its composition can be compared to waste acceptance and hazard criteria, verifying actinide and strontium adsorption with a small scale test using monosodium titanate (MST) and filtration, checking MCU solvent performance when applied to the liquid produced from MST contact, and verifying that in-tank settling after a minimum of 30 days was at least as good or better at reducing solids content after a Tank 49H to Tank 50H transfer occurred than what was observed in less time in the lab. The first four items were covered by Sample Set A. The fifth item was covered by Sample Set C, which had several analyses after compositing as required in the nuclear criticality safety evaluation (NCSE).

  12. Feed tank transfer requirements

    International Nuclear Information System (INIS)

    This document presents a definition of tank turnover; DOE responsibilities; TWRS DST permitting requirements; TWRS Authorization Basis (AB) requirements; TWRS AP Tank Farm operational requirements; unreviewed safety question (USQ) requirements; records and reporting requirements, and documentation which will require revision in support of transferring a DST in AP Tank Farm to a privatization contractor for use during Phase 1B

  13. Tank 241-AZ-101 tank characterization plan

    International Nuclear Information System (INIS)

    The Defense Nuclear Facilities Safety Board has advised the DOE to concentrate the near-term sampling and analysis activities on identification and resolution of safety issues. The Data Quality Objective (DQO) process was chosen as a tool to be used in the resolution of safety issues. As a result, A revision in the Federal Facilities Agreement and Consent Order (Tri-Party Agreement) milestone M-44 has been made, which states that ''A Tank Characterization Plan (TCP) will also be developed for each double-shell tank (DST) and single-shell tank (SST) using the DQO process. Development of TCPs by the DQO process is intended to allow users to ensure their needs will be met and that resources are devoted to gaining only necessary information''. This document satisfies that requirement for Tank 241-AZ-101 (AZ-101) sampling activities. Tank AZ-101 is currently a non-Watch List tank, so the only DQOs applicable to this tank are the safety screening DQO and the compatibility DQO, as described below. The contents of Tank AZ-101, as of October 31, 1994, consisted of 3,630 kL (960 kgal) of dilute non-complexed waste and aging waste from PUREX (NCAW, neutralized current acid waste). Tank AZ-101 is expected to have two primary layers. The bottom layer is composed of 132 kL of sludge, and the top layer is composed of 3,500 kL of supernatant, with a total tank waste depth of approximately 8.87 meters

  14. Tank 241-AZ-102 tank characterization plan

    International Nuclear Information System (INIS)

    The Defense Nuclear Facilities Safety Board has advised the DOE to concentrate the near-term sampling and analysis activities on identification and resolution of safety issues. The Data Quality Objective (DQO) process was chosen as a tool to be used in the resolution of safety issues. As a result, a revision in the Federal Facilities Agreement and Consent Order (Tri-Party Agreement) milestone M-44 has been made, which states that ''A Tank Characterization Plan (TCP) will also be developed for each double-shell tank (DST) and single-shell tank (SST) using the DQO process ... Development of TCPs by the DQO process is intended to allow users to ensure their needs will be met and that resources are devoted to gaining only necessary information''. This document satisfies that requirement for tank 241-AZ-102 (AZ-102) sampling activities. Tank AZ-102 is currently a non-Watch List tank, so the only DQOs applicable to this tank are the safety screening DQO and the compatibility DQO, as described below. The current contents of Tank AZ-102, as of October 31, 1994, consisted of 3,600 kL (950 kgal) of dilute non-complexed waste and aging waste from PUREX (NCAW, neutralized current acid waste). Tank AZ-102 is expected to have two primary layers. The bottom layer is composed of 360 kL of sludge, and the top layer is composed of 3,240 kL of supernatant, with a total tank waste depth of approximately 8.9 meters

  15. Aeration aggressive radon waters in water supply management

    International Nuclear Information System (INIS)

    222Rn and CO2 must be removed in the treatment of drinking water. Three methods are suggested of the aeration of radon waters, where ceramic filter candles, frits, or filter heads are used. A comparison is made of the three methods and tabulated. Taking into account the technical aspects of water treatment and the effects of radiation on the oro.anism, a reduction in 222Rn content down to 5 to 10 Bq/l may be considered purposeful. (E.S.)

  16. DIGITAL IMAGE MEASUREMENT OF BUBBLE MOTION IN AERATED WATER FLOWS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Digital image measurement method, as an ex-tension of Particle Image Velocimetry of single-phase flowmeasurement, was investigated for application to air-watertwo-phase flows. The method has strong potential ability inmeasuring bubble geometrical features and moving velocitiesfor complex bubble motion in aerated water flow. Both dilutedand dense bubble rising flows are measured using the digitalimage method. Measured bubble shapes and sizes, and bubblevelocities are affected by threshold selection for binary image.Several algorithms for selecting threshold are compared andmethods for calculating the time-averaged void fraction arediscussed.

  17. Pulverizing aeration as a method of lakes restoration

    Science.gov (United States)

    Kaczorowska, E.; Podsiadłowski, S.

    2012-04-01

    The principal threat to lakes of the temperate zone is posed by factors accelerating their eutrophication and causing marked deoxygenation of the deeper layers of water, mainly the hypo- and metalimnion. Among their effects are frequent phytoplankton blooms, including those of blue-green algae, and general deterioration of water quality also affecting the abundance and health status of fish. The chief concern is a disturbed proportion between the amount of complex chemical compounds, especially organic, and the oxygen content of lake waters. Natural processes of water oxygenation are not too intensive, because they are practically limited to the epilimnion layer, connected as they are with the activity of aquatic plants of the littoral and sublittoral zone (which tends to disappear in contaminated lakes) and wind energy (the effect of waving). In summer conditions, with a relatively great chemical activity of bottom deposits, the intensity of those processes is usually inadequate. Hence, in 1995 a research was launched in the Institute of Agricultural Engineering of the Agricultural University in Poznań on an integrated lake restoration technology whose core was a self-powered aerator capable of oxygenating also the bottom layers of water (the hypolimnion) of deep lakes. The aerator uses energy obtained from a Savonius rotor mainly to diffuse gases: to release hydrogen sulphide, which usually saturates the hypolimnion water completely, and then to saturate this water with oxygen. Even early studies showed the constructed device to be highly efficient in improving oxygen conditions in the bottom zone. They also made it clear that it should be equipped with an autonomous system designed to inactivate phosphorus, one of the principal factors determining the rate of lake degradation. In 2003 the first wind-driven pulverising aerator equipped with such a system was installed in Town Lake in Chodzież. The aim of this work is to present the principles of operation of a

  18. Optimization of a production line of aerated concrete

    International Nuclear Information System (INIS)

    The process optimization of large-scale production plant for the manufacture of aerated concrete was performed by means of tracer techniques. The behaviour of all components which were labelled with short-lived radionuclides such as 18F, 24Na, 42K, 43Sc, and 140La were investigated both in a 3-chamber ball mill and in a wet mixer. Based on the results obtained the technological parameters of the production plant could be changed in order to increase the economical effectiveness. (author)

  19. Remediation of a former tank farm : Saviktok Point, NWT

    Energy Technology Data Exchange (ETDEWEB)

    Gingras, P. [Biogenie Inc., Quebec City, PQ (Canada)

    2008-07-01

    A former tank farm was remediated in Saviktok Point, Northwest Territories (NWT). This presentation discussed the site characteristics and presented several photographs of the tank farm location. The remote location did not have any source of electrical power and was accessible only by sea. It had limited availability of equipment, materials and manpower. The preferred solution for the hydrocarbon contamination was biological treatment, which requires oxygen gas to maximize the degradation of contaminants. Other key aspects of biological treatment include the need for heat to sustain microbial activity; use of nitrogen and phosphorous; neutral pH and loose structure and moisture content. Several photographs were provided to illustrate treatment technologies; bench scale trials; and the use of wind turbines for soil aeration. A chart that demonstrated bioremediation efficiency at Saviktok Point was presented. The presentation revealed that over a 3 season period 17,000 cubic metres were treated to NWT industrial standards. The average temperatures during treatment was 30 degrees Celsius and soils were recycled as landfill cover material. The presentation concluded with a discussion Saviktok Point benefits, such as the minimization of soil handling; utilization of a wind-powered aeration system; adapted design of the biological treatment to site-specific conditions; and maximum use of local resources. figs.

  20. Numerical simulation of Hanford Tank 241-SY-101 jet initiated fluid dynamics

    International Nuclear Information System (INIS)

    The episodic Gas Release Events (GREs) that have characterized the behavior of Hanford tank 241-SY-101 for the past several years are thought to result from the entrapment of gases generated in the settled solids, i.e., sludge, layer of the tank. Gases consisting of about 36% hydrogen by volume, which are generated by complicated and poorly understood radiological and chemical processes, are apparently trapped in the settled solids layer until their accumulation initiates a buoyant upset of this layer, abruptly releasing large quantities of gas. Once concept for preventing the gas accumulation is to mobilize the settled materials with jet mixing. It is suggested that continual agitation of the settled solids using a mixer pump would free the gas bubbles so that they could continually escape, thus mitigating the potential for accumulation of flammable concentrations of hydrogen in the tank dome space following a GRE. A pump test is planned to evaluate the effectiveness of the jet mixing mitigation concept. The pump will circulate liquid from the upper layer of the tank, discharging it through two horizontal jets located approximately 2 1/2 ft above the tank floor. To prepare for start-up of this pump test, technical, operation, and safety questions concerning an anticipated gas release were addressed by numerical simulation using the TEMPEST computer code. Simulations of the pump initiated gas release revealed that the amount of gas that could potentially be released to the tank dome space is very sensitive to the initial conditions assumed for the amount and distribution of gas in the sludge layer. Calculations revealed that within the assumptions regarding gas distribution and content, the pump might initiate a rollover--followed by a significant gas release--if the sludge layer contains more than about 13 to 14% gas distributed with constant volume fraction

  1. External corrosion of tanks 8D-1 and 8D-2. Final report

    International Nuclear Information System (INIS)

    Tanks 8D-1 and 8D-2 at the West Valley Nuclear Services (WVNS) site, West Valley, New York, rest on layers of perlite brick contained within steel pans. The pans tend to collect water, which can contact the tanks directly and which also can be ''wicked'' to the external surfaces of the tank through the perlite brick. The presence of air in the tank vault is conducive to the formation of oxygen concentration cells, which can promote localized corrosion of the carbon steel tank wall. Pacific Northwest Laboratory conducted an experiment to estimate the extent to which the external surfaces of the tanks could have corroded in the 30 years since their construction. Specimens of carbon steel, similar to that used in the tank construction, were partially embedded in an upright position in particulate perlite in closed containers. The water line in the containers.was maintained at two levels: above the perlite level (high water level tests) and below the bottoms of the specimens (low water level tests). The water used in the tests was obtained from the pan of tank 8D-1. The containers were maintained in an aerated condition. Specimens were examined after 3-, 6-, 12-, 18-, 24-, and 30-month exposures

  2. Industrial mixing techniques for Hanford double-shell tanks

    International Nuclear Information System (INIS)

    Jet mixer pumps are currently the baseline technology for sludge mobilization and mixing in one-million gallon double-shell tanks at the Hanford and Savannah River Sites. Improvements to the baseline jet mixer pump technology are sought because jet mixer pumps have moving parts that may fail or require maintenance. Moreover, jet mixers are relatively expensive, they heat the waste, and, in some cases, may not mobilize enough of the sludge. This report documents a thorough literature search for commercially available applicable mixing technologies that could be used for double-shell tank sludge mobilization and mixing. Textbooks, research articles, conference proceedings, mixing experts, and the Thomas Register were consulted to identify applicable technologies. While there are many commercial methods that could be used to mobilize sludge or mix the contents of a one-million gallon tank, few will work given the geometrical constraints (e.g., the mixer must fit through a 1.07-m-diameter riser) or the tank waste properties (e.g., the sludge has such a high yield stress that it generally does not flow under its own weight). Pulsed fluid jets and submersible Flygt mixers have already been identified at Hanford and Savannah River Sites for double-shell tank mixing applications. While these mixing technologies may not be applicable for double-shell tanks that have a thick sludge layer at the bottom (since too many of these mixers would need to be installed to mobilize most of the sludge), they may have applications in tanks that do not have a settled solids layer. Retrieval projects at Hanford and other U.S. Department of Energy sites are currently evaluating the effectiveness of these mixing techniques for tank waste applications. The literature search did not reveal any previously unknown technologies that should be considered for sludge mobilization and mixing in one-million gallon double-shell tanks

  3. Industrial mixing techniques for Hanford double-shell tanks

    Energy Technology Data Exchange (ETDEWEB)

    Daymo, E.A.

    1997-09-01

    Jet mixer pumps are currently the baseline technology for sludge mobilization and mixing in one-million gallon double-shell tanks at the Hanford and Savannah River Sites. Improvements to the baseline jet mixer pump technology are sought because jet mixer pumps have moving parts that may fail or require maintenance. Moreover, jet mixers are relatively expensive, they heat the waste, and, in some cases, may not mobilize enough of the sludge. This report documents a thorough literature search for commercially available applicable mixing technologies that could be used for double-shell tank sludge mobilization and mixing. Textbooks, research articles, conference proceedings, mixing experts, and the Thomas Register were consulted to identify applicable technologies. While there are many commercial methods that could be used to mobilize sludge or mix the contents of a one-million gallon tank, few will work given the geometrical constraints (e.g., the mixer must fit through a 1.07-m-diameter riser) or the tank waste properties (e.g., the sludge has such a high yield stress that it generally does not flow under its own weight). Pulsed fluid jets and submersible Flygt mixers have already been identified at Hanford and Savannah River Sites for double-shell tank mixing applications. While these mixing technologies may not be applicable for double-shell tanks that have a thick sludge layer at the bottom (since too many of these mixers would need to be installed to mobilize most of the sludge), they may have applications in tanks that do not have a settled solids layer. Retrieval projects at Hanford and other U.S. Department of Energy sites are currently evaluating the effectiveness of these mixing techniques for tank waste applications. The literature search did not reveal any previously unknown technologies that should be considered for sludge mobilization and mixing in one-million gallon double-shell tanks.

  4. Engineering study of 50 miscellaneous inactive underground radioactive waste tanks located at the Hanford Site, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Freeman-Pollard, J.R.

    1994-03-02

    This engineering study addresses 50 inactive underground radioactive waste tanks. The tanks were formerly used for the following functions associated with plutonium and uranium separations and waste management activities in the 200 East and 200 West Areas of the Hanford Site: settling solids prior to disposal of supernatant in cribs and a reverse well; neutralizing acidic process wastes prior to crib disposal; receipt and processing of single-shell tank (SST) waste for uranium recovery operations; catch tanks to collect water that intruded into diversion boxes and transfer pipeline encasements and any leakage that occurred during waste transfer operations; and waste handling and process experimentation. Most of these tanks have not been in use for many years. Several projects have, been planned and implemented since the 1970`s and through 1985 to remove waste and interim isolate or interim stabilize many of the tanks. Some tanks have been filled with grout within the past several years. Responsibility for final closure and/or remediation of these tanks is currently assigned to several programs including Tank Waste Remediation Systems (TWRS), Environmental Restoration and Remedial Action (ERRA), and Decommissioning and Resource Conservation and Recovery Act (RCRA) Closure (D&RCP). Some are under facility landlord responsibility for maintenance and surveillance (i.e. Plutonium Uranium Extraction [PUREX]). However, most of the tanks are not currently included in any active monitoring or surveillance program.

  5. Engineering study of 50 miscellaneous inactive underground radioactive waste tanks located at the Hanford Site, Washington

    International Nuclear Information System (INIS)

    This engineering study addresses 50 inactive underground radioactive waste tanks. The tanks were formerly used for the following functions associated with plutonium and uranium separations and waste management activities in the 200 East and 200 West Areas of the Hanford Site: settling solids prior to disposal of supernatant in cribs and a reverse well; neutralizing acidic process wastes prior to crib disposal; receipt and processing of single-shell tank (SST) waste for uranium recovery operations; catch tanks to collect water that intruded into diversion boxes and transfer pipeline encasements and any leakage that occurred during waste transfer operations; and waste handling and process experimentation. Most of these tanks have not been in use for many years. Several projects have, been planned and implemented since the 1970's and through 1985 to remove waste and interim isolate or interim stabilize many of the tanks. Some tanks have been filled with grout within the past several years. Responsibility for final closure and/or remediation of these tanks is currently assigned to several programs including Tank Waste Remediation Systems (TWRS), Environmental Restoration and Remedial Action (ERRA), and Decommissioning and Resource Conservation and Recovery Act (RCRA) Closure (D ampersand RCP). Some are under facility landlord responsibility for maintenance and surveillance (i.e. Plutonium Uranium Extraction [PUREX]). However, most of the tanks are not currently included in any active monitoring or surveillance program

  6. Vibration Considerations for Cryogenic Tanks Using Glass Bubbles Insulation

    Science.gov (United States)

    Werlink, Rudolph J.; Fesmire, James E.; Sass, Jared P.

    2011-01-01

    The use of glass bubbles as an efficient and practical thermal insulation system has been previously demonstrated in cryogenic storage tanks. One such example is a spherical, vacuum-jacketed liquid hydrogen vessel of 218,000 liter capacity where the boiloff rate has been reduced by approximately 50 percent. Further applications may include non-stationary tanks such as mobile tankers and tanks with extreme duty cycles or exposed to significant vibration environments. Space rocket launch events and mobile tanker life cycles represent two harsh cases of mechanical vibration exposure. A number of bulk fill insulation materials including glass bubbles, perlite powders, and aerogel granules were tested for vibration effects and mechanical behavior using a custom design holding fixture subjected to random vibration on an Electrodynamic Shaker. The settling effects for mixtures of insulation materials were also investigated. The vibration test results and granular particle analysis are presented with considerations and implications for future cryogenic tank applications. A thermal performance update on field demonstration testing of a 218,000 L liquid hydrogen storage tank, retrofitted with glass bubbles, is presented. KEYWORDS: Glass bubble, perlite, aerogel, insulation, liquid hydrogen, storage tank, mobile tanker, vibration.

  7. Updating a model of pulp and paper wastewater treatment in a partial-mix aerated stabilization basin system.

    Science.gov (United States)

    Bryant, Curtis W

    2010-01-01

    A relatively simple set of calculations was presented in 1994 to evaluate the effectiveness of each ASB cell as reactor, clarifier, and digester. The steady-state model, which incorporated estimates of solids settling and benthal feedback of BOD5 and nutrients, has been a reasonable diagnostic tool for municipal and industrial applications. Results have aided in understanding normal system function, the nature of chronic inefficiencies of individual systems, and appropriate modifications to meet changes in discharge requirements. For applications in the pulp and paper industry, several changes have been incorporated recently. Nitrogen limitation is not needed in modeling pulp and paper ASB reactions. Slowly biodegradable material is modeled as a contributor to soluble BOD5, and this contribution becomes a significant factor in the latter segments of an ASB. Phosphorus availability is modeled as a stoichiometric control of soluble BOD5 uptake. Anoxic microorganisms are assumed to be responsible for a portion of the soluble BOD5 consumption in the first ASB aeration zone. Finally, the long-term nutrient capture in ASBs is modeled as 3% for nitrogen and 28% for phosphorus. PMID:20861537

  8. On The Possible Leakage of ET-RR1 Liquid Waste Tank: Hydrological and Migration Modes Studies

    OpenAIRE

    N. S. Mahmoud; EL-Hemamy, S. T.

    2005-01-01

    The first Egyptian (ET-RR1) research reactor has been in operation since 1961 at the Egyptian Atomic Energy Authority (EAEA) Inshas site. Therefore, at present, it faces a serious problem due to aging equipment, especially those directly in contact with the environment such as the underground settling tanks of nuclear and radioactive waste. The possible leakage of radionuclides from these aging tanks and their migration to the aquifer was studied using instantaneous release.This study was don...

  9. Tank 241-B-103 tank characterization plan

    International Nuclear Information System (INIS)

    The Defense Nuclear Facilities Safety Board (DNFSB) has advised the US Department of Energy (DOE) to concentrate the near-term sampling and analysis activities on identification and resolution of safety issues. The data quality objective (DQO) process was chosen as a tool to be used to identify sampling and analytical needs for the resolution of safety issues. As a result, a revision in the Federal Facility Agreement and Consent Order (Tri-Party Agreement or TPA) milestone M-44-00 has been made, which states that ''A Tank Characterization Plan (TCP) will also be developed for each double-shell tank (DST) and single-shell tank (SST) using the DQO process... Development of TCPs by the DQO process is intended to allow users (e.g., Hanford Facility user groups, regulators) to ensure their needs will be met and that resources are devoted to gaining only necessary information.'' This document satisfies that requirement for Tank 241-B-103 (B-103) sampling activities. Tank B-103 was placed on the Organic Watch List in January 1991 due to review of TRAC data that predicts a TOC content of 3.3 dry weight percent. The tank was classified as an assumed leaker of approximately 30,280 liters (8,000 gallons) in 1978 and declared inactive. Tank B-103 is passively ventilated with interim stabilization and intrusion prevention measures completed in 1985

  10. Physical Property and Rheological Testing of Actual Transuranic Waste from Hanford Single-Shell Tanks

    International Nuclear Information System (INIS)

    Composites of sludge from Hanford tanks 241-B-203 (B-203), 241-T-203 (T-203), 241-T-204 (T-204), and 241-T-110 (T-110) were prepared at the Hanford 222-S Laboratory and transferred to the Radiochemical Processing Laboratory at the Pacific Northwest National Laboratory (PNNL) for measurement of the composites' physical properties. These tank composites were prepared from core samples retrieved from these tanks. These core samples may not be representative of the entire contents of the tank but provide some indication of the properties of the waste in these underground storage tanks. Dilutions in water were prepared from the composite samples. The measurements included paint filter tests, viscosity, shear strength, settling and centrifuging behavior, a qualitative test of stickiness, total solids concentration, and extrusion tests to estimate shear strength.

  11. Physical Property and Rheological Testing of Actual Transuranic Waste from Hanford Single-Shell Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Tingey, Joel M.(BATTELLE (PACIFIC NW LAB)); Gao, Johnway (BATTELLE (PACIFIC NW LAB)); Delegard, Calvin H.(BATTELLE (PACIFIC NW LAB)); Bagaasen, Larry M.(BATTELLE (PACIFIC NW LAB)); Wells, Beric E.(BATTELLE (PACIFIC NW LAB))

    2003-08-25

    Composites of sludge from Hanford tanks 241-B-203 (B-203), 241-T-203 (T-203), 241-T-204 (T-204), and 241-T-110 (T-110) were prepared at the Hanford 222-S Laboratory and transferred to the Radiochemical Processing Laboratory at the Pacific Northwest National Laboratory (PNNL) for measurement of the composites' physical properties. These tank composites were prepared from core samples retieved from these tanks. These core samples may not be representative of the entire contents of the tank but provide some indication of the properties of the waste in these underground storage tanks. Dilutions in water were prepared from the composite samples. The measurements included paint filter tests, viscosity, shear strength, settling and centrifuging behavior, a qualitative test of stickiness, total solids concentration, and extrusion tests to estimate shear strength.

  12. Think Tanks in Europe

    DEFF Research Database (Denmark)

    Kelstrup, Jesper Dahl

    The emergence of more think tanks in recent decades has spawned some interest in how they function and impact policy-making in the European Union and its member states. So far however few empirical studies of think tanks have been carried out and think tanks have mainly been studied in their...... national contexts. Questions regarding patterns and differences in think tank organisations and functions across countries have largely been left unanswered. This paper advances a definition and research design that uses different expert roles to categorise think tanks. A sample of 34 think tanks from...... Brussels, Denmark and Germany are categorised according to different expert roles in a pilot analysis. As the analysis is sensitive to the interpretation and weight given to different indicators, besides from picturing the think tank landscape, the analysis is intended to trigger a discussion of how and...

  13. Filling Tanks with Hydrazine

    Science.gov (United States)

    Krueger, K.

    2004-10-01

    At the Hydrazine workshop in 2002 in Noordwijk several presentations dealt with the filling of satellite tanks. I was a bit surprised about the amount of manpower that is needed for this work. But I saw the same during the filling of the SCA system tanks some years ago in Trauen/Germany. I want to present the work flow of filling RESUS Hydrazine tanks. This bladder tanks have a capacity of 64 litres and are similar to some of the satellite tanks. We fill this tanks 25 to 50 times a year. Although the specifications are not exactly the same as those for satellite tank filling, it might be interesting to see how this work can be done half-automatically, because handling with Hydrazine is not a nice job, and the faster it goes, the better.

  14. The use of bottle caps as submerged aerated filter medium.

    Science.gov (United States)

    Damasceno de Oliveira, Laurence; Motlagh, Amir Mohaghegh; Goel, Ramesh; de Souza Missagia, Beatriz; Alves de Abreu Filho, Benício; Lautenschlager, Sandro Rogério

    2014-01-01

    In this study, a submerged aerated filter (SAF) using bottle caps as a support medium was evaluated. The system was fed with effluent from an upflow anaerobic sludge blanket system at ETE 2-South wastewater treatment plant, under different volumetric organic load rates (VOLRs). The population of a particular nitrifying microbial community was assessed by fluorescent in situ hybridization with specific oligonucleotide probes. The system showed an average removal of chemical oxygen demand (COD) equal to 76% for VOLRs between 2.6 and 13.6 kg COD m(-3)_media.day(-1). The process of nitrification in conjunction with the removal of organic matter was observed from applying VOLRs lower than 5.5 kg COD m(-3)_media.day(-1) resulting in 78% conversion of NH4(+)-N. As the applied organic load was reduced, an increase in the nitrifying bacteria population was observed compared with total 4'-6-diamidino-2-phenylindole (DAPI) stained cells. Generally, SAF using bottle caps as a biological aerated filter medium treating wastewater from an anaerobic system showed promising removal of chemical oxygen demand (COD) and conversion of NH4(+)-N. PMID:24718345

  15. 3D CT Imaging Method for Measuring Temporal Bone Aeration

    International Nuclear Information System (INIS)

    Objective: 3D volume reconstruction of CT images can be used to measure temporal bene aeration. This study evaluates the technique with respect to reproducibility and acquisition parameters. Material and methods: Helical CT images acquired from patients with radiographically normal temporal bones using standard clinical protocols were retrospectively analyzed. 3D image reconstruction was performed to measure the volume of air within the temporal bone. The appropriate threshold values for air were determined from reconstruction of a phantom with a known air volume imaged using the same clinical protocols. The appropriate air threshold values were applied to the clinical material. Results: Air volume was measured according to an acquisition algorithm. The average volume in the temporal bone CT group was 5.56 ml, compared to 5.19 ml in the head CT group (p = 0.59). The correlation coefficient between examiners was > 0.92. There was a wide range of aeration volumes among individual ears (0.76-18.84 ml); however, paired temporal bones differed by an average of just 1.11 ml. Conclusions: The method of volume measurement from 3D reconstruction reported here is widely available, easy to perform and produces consistent results among examiners. Application of the technique to archival CT data is possible using corrections for air segmentation thresholds according to acquisition parameters

  16. The Potential of Extended Aeration System for Sago Effluent Treatment

    Directory of Open Access Journals (Sweden)

    Wahi A. Rashid

    2010-01-01

    Full Text Available Problem statement: Sago effluent contains large amount of organic material which has a potential to cause water pollution. In order to reduce this problem, an experiment was conducted to remove organic material from sago effluent using lab scale of Extended Aeration (EA system. Approach: The EA system consisted of the combination of physical and biological treatment unit. For Physical Treatment Unit (PTU, the sago effluent was filtered using 710 µm mesh size filter. For Biological Treatment Unit (BTU, the effluent were mixed and aerated with activated sago sludge for 48 h. The treatment efficiency with respect to Biological Oxygen Demand (BOD, Chemical Oxygen Demand (COD and Total Suspended Solid (TSS removal were evaluated and compared with regulatory requirement by Department of Environment, Malaysia. Results: The result showed, the EA system could reduce BOD, COD and TSS up to 84, 87.8 and 73% respectively, however it did not comply with the regulatory requirement. Conclusion: This study suggested the EA system have potential to be apply on sago effluent, however it should be integrated with additional treatment unit to achieve the effluent quality standard.

  17. Aggregate formation and collision efficiency in differential settling.

    Science.gov (United States)

    Kim, Albert S; Stolzenbach, Keith D

    2004-03-01

    A new method of application of Stokesian dynamics, which can efficiently simulate movements of up to 500 particles with interparticle interactions in reasonable computational times, has been developed for the purpose of investigating particle-cluster aggregation in aqueous systems. The method is applied to monodisperse non-Brownian spherical particles aggregating in differential settling, while repulsive colloidal interaction is presumed to be negligible, so that a minimum separation distance can represent the attractive van der Waals force. The final aggregates formed by this algorithm, composed of 300 primary particles, have a common fractal dimension of approximately 2.0. The computed collision efficiency, defined as the product of a global and a capture efficiency, is about 5.77x10(-3). This value is significantly larger than the collision efficiency of primary particles colliding with an impermeable solid sphere of the same size as the aggregate, illustrating the important interplay between the permeability and the formation of aggregates. PMID:14757083

  18. Hydrodynamic characteristics of high speed settling clarifiers by radiotracer method

    International Nuclear Information System (INIS)

    Results achieved in the evaluation of two high-speed settling cane juice Clarifiers, one denominated ICINAZ The Express and the other one with Low Residence Time (BTR), both located at the sugar factory Orlando Gonzalez employing the well established radiotracer method (Tc-99m) are presented. Several trials performed at the two Clarifiers demonstrated that the one identified as BTR was capable to assimilate the whole flow capacity of the factory with adequate characteristic of the pattern flux and residence time in the environment of 1 hour. In the other side, ICINAZ The Express Clarifier could only work at relative low flow capacity of the factory with residence time closely to the two hours and achieving occasionally a pattern flux seriously affected by fluctuations in the milling process. The radiotracer method was able to detect certain differences between the two clear juice outlet of the BTR Clarifier, probably due some problems in the construction of this equipment

  19. Settling the Complexity of Computing Two-Player Nash Equilibria

    CERN Document Server

    Chen, Xi; Teng, Shang-Hua

    2007-01-01

    We settle a long-standing open question in algorithmic game theory. We prove that Bimatrix, the problem of finding a Nash equilibrium in a two-player game, is complete for the complexity class PPAD Polynomial Parity Argument, Directed version) introduced by Papadimitriou in 1991. This is the first of a series of results concerning the complexity of Nash equilibria. In particular, we prove the following theorems: Bimatrix does not have a fully polynomial-time approximation scheme unless every problem in PPAD is solvable in polynomial time. The smoothed complexity of the classic Lemke-Howson algorithm and, in fact, of any algorithm for Bimatrix is not polynomial unless every problem in PPAD is solvable in randomized polynomial time. Our results demonstrate that, even in the simplest form of non-cooperative games, equilibrium computation and approximation are polynomial-time equivalent to fixed point computation. Our results also have two broad complexity implications in mathematical economics and operations res...

  20. Mesoscopic stability and sedimentation waves in settling periodic arrays.

    Science.gov (United States)

    Felderhof, B U

    2003-11-01

    The stability of a periodic array of particles settling in a viscous incompressible fluid under the influence of gravity is investigated in the framework of the point sedimentation model. The simple cubic array is unstable, but the body-centered and face-centered cubic arrays with gravity directed along one of the crystal axes are mesoscopically stable, i.e., they are stable except for very long wavelength in a certain domain of directions of the wave vector. In such mesoscopically stable arrays the instability is suppressed in periodic boundary conditions for systems smaller than a maximum size. In a stable finite system the particles perform small motions about the positions of the regular array, and sedimentation waves propagate through the system. PMID:14682796

  1. Preparation of air-settled, roll-thinned phosphorus targets

    CERN Document Server

    Lozowski, W R

    1999-01-01

    Red sup 3 sup 1 P targets of 2.6 and 2.9 mg/cm sup 2+-0.1 mg/cm sup 2 with 1-cmx2-cm side dimensions were prepared for a nuclear mass measurement which required good thickness uniformity. The thinner target, with 50 mu g/cm sup 2 of gold flashed on both surfaces, withstood a 173-MeV alpha beam of 175 nA for 18 h. Adaptations will be described for an Indiana University Cyclotron Facility air-settling method used to distribute phosphorus powder, as well as the methods developed for subsequent pressing, roll thinning, and dry release to obtain self-supporting targets. An envelope of gold foil, in contact with the phosphorus during each step, was instrumental in the process.

  2. 49 CFR 179.400 - General specification applicable to cryogenic liquid tank car tanks.

    Science.gov (United States)

    2010-10-01

    ... liquid tank car tanks. 179.400 Section 179.400 Transportation Other Regulations Relating to... MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and... liquid tank car tanks....

  3. Experimental investigations of aeration efficiency in high-head gated circular conduits.

    Science.gov (United States)

    Cihat Tuna, M; Ozkan, Fahri; Baylar, Ahmet

    2014-01-01

    The primary purpose of water aeration is to increase the oxygen saturation of the water. This can be achieved by using hydraulic structures because of substantial air bubble entrainment at these structures. Closed conduit aeration is a particular instance of this. While there has been a great deal of research on air-demand ratio within closed conduit, very little research has specifically addressed aeration efficiency of closed conduit. In the present work an experimental study was conducted to investigate the aeration efficiency of high-head gated circular conduits. Results showed that high-head gated circular conduits were effective for oxygen transfer. The effects of Froude number and ratio of the water cross-sectional flow area to the conduit cross-sectional area on aeration efficiency were particularly significant, whereas the effect of conduit length was only moderate. Further, a design formula for the aeration efficiency was presented relating the aeration efficiency to ratio of water cross-sectional flow area to conduit cross-sectional area and Froude number. The obtained results will be useful in future modeling processes and aid the practicing engineer in predicting aeration efficiency for design purposes. PMID:24647194

  4. Biodegradation of diesel oil and gasoline contaminated effluent employing intermittent aeration.

    Science.gov (United States)

    Vieira, P A; Vieira, R B; Faria, S; Ribeiro, E J; Cardoso, V L

    2009-09-15

    We examined the effects of aeration interval and agitation speed in an effort to optimize the biodegradation of effluent contaminated with diesel oil and gasoline. The biodegradation process employed a C(1) mixed culture and intermittent aeration. Optimization was performed using central composite design (CCD). The independent variables were aeration interval (X(1)) and agitation speed (X(2)) and the dependent variable was the degree of removal of total petroleum hydrocarbons (TPH). The optimum aeration interval (33h) and agitation speed (110rpm) resulted in TPH removal of 75.9% after 3 days. Five hydrocarbons classes were identified using gas chromatography: paraffins, isoparaffins, olefins, naphthenics, and aromatics. The following reductions were observed: 91.8% for the paraffins, 83.3% for the isoparaffins, 80.9% for the olefins, 39.3% for the naphthenics, and 80.9% for the aromatics. In comparative studies performed under constant aeration (CA), without aeration (WA), and intermittent aeration (IA) conditions, intermittent aeration resulted in the highest TPH removals, with 90% reduction after 22 days. Under the IA condition, the degradation percentages were 99.6% for the paraffins, 94% for the isoparaffins, 95.4% for the olefins, 70.8 for the naphthenics, and 83.4% for the aromatics. PMID:19356851

  5. Evaluating aeration techniques for decreasing phosphorus export from grasslands receiving manure

    Science.gov (United States)

    Given that surface-applied manures can contribute to phosphorus (P) in runoff, a study was conducted to examine mechanical aeration of grasslands for reducing P transport by increasing infiltration of rainfall and binding of P with soil minerals. The effects of three aeration treatments and a contr...

  6. Aerated Shewanella oneidensis in Continuously-fed Bioelectrochemical Systems for Power and Hydrogen Production

    Science.gov (United States)

    We studied the effects of aeration of Shewanella oneidensis on potentiostatic current production, iron(III) reduction, hydrogen production in a microbial electrolysis cell, and electric power generation in a microbial fuel cell. The potentiostatic performance of aerated S. oneidensis was considerab...

  7. 40 CFR 265.278 - Unsaturated zone (zone of aeration) monitoring.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Unsaturated zone (zone of aeration) monitoring. 265.278 Section 265.278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., STORAGE, AND DISPOSAL FACILITIES Land Treatment § 265.278 Unsaturated zone (zone of aeration)...

  8. EXPERIMENTAL STUDY ON A NEW TYPE OF AERATOR IN SPILLWAY WITH LOW FROUDE NUMBER AND MILD SLOPE FLOW

    Institute of Scientific and Technical Information of China (English)

    SU Pei-lan; LIAO Hua-sheng; QIU Yue; LI Chen-juan

    2009-01-01

    Experimental study on aeration characteristics of various aeration devices was conducted in the spillway tunnel of the Pubugou hydropower project, Sichuan Province, China. It is shown by comparison that the new type of aeration device, namely, the aerator with a trapezoidal-shaped slot and a steep-slope section(ATSS), can avoid water accumulation in the cavity of the aeration device in the project, thus can effectively solve the backwater problems arising from this project and be used for a wide range of different water levels, without any drain facilities. Above the water level of 840 m, the water contained in the cavity can be eliminated completely, which means that the recommended new type of aerator can meet the aeration demands in the spillway of the project with low Froude number and may be of practical significance and of interest to other projects with similar types of aeration devices.

  9. Status report for inactive miscellaneous underground storage tanks at Hanford Site 200 Areas

    International Nuclear Information System (INIS)

    The purpose of this status report is to summarize updated data and information from the FY 1994 strategy plan that is associated with inactive miscellaneous underground storage tanks (IMUSTs). Assumptions and processes to assess potential risks and operational concerns are documented in this report. Safety issue priorities are ranked based on a number of considerations. Sixty-three IMUSTs have been Identified and placed on the official IMUST list. All the tanks are associated with past Hanford Site operations. Of the 63 tanks., 19 are catch tanks, 20 are vault tanks, 3 are neutralization tanks, 8 are settling tanks, 2 are solvent makeup tanks used to store hexone, 2 are flush tanks, 3 are decontamination tanks, 1 is a diverter station, 1 is a receiver tank, 1 is an experimental tank, and 3 are waste handling tanks. It is important to proactively deal with the risks Imposed by these 63 tanks, and at the same time not jeopardize the existing commitments and schedules for mitigating and resolving identified safety issues related to the 177 SSTs and DSTS. Access controls and signs have been placed on all but the three official IMUSTs added most recently. An accelerated effort to identify authorization documents and perform unreviewed safety question (USQ) screening has been completed. According to a set of criteria consistent with the safety screening data quality objective (DQO) process, 6 IMUSTs are ranked high related to the hydrogen generation potential safety Issue, 1 is ranked high related to the ferrocyanide potential safety issue, 6 are ranked high related to the flammability potential safety issue, and 25 are ranked high related to the vapor emissions potential safety issue

  10. FUNCTIONS AND REQUIREMENTS FOR RUSSIAN PULSATING MONITOR DEPLOYMENT IN THE GUNITE AND ASSOCIATED TANKS AT OAK RIDGE NATIONAL LABORATORY

    International Nuclear Information System (INIS)

    This document provides functions and requirements to support deployment of pulsating mixer pump technology in the Oak Ridge National Laboratory (ORNL) Gunite and Associated Tanks to mobilize and mix the settled sludge and solids in these tanks. In FY 1998 pulsating mixer pump technology, a jet mixer powered by a reciprocating air supply, was selected for FY 1999 deployment in one of the GAAT tanks to mobilize settled solids. Pulsating mixer pump technology was identified in FY 1996 during technical exchanges between the US Department of Energy (DOE) Tanks Focus Area Retrieval and Closure program, the DOE Environmental Management International Programs, and delegates from Russia as a promising technology that could be implemented in the US. The pulsating mixer pump technology, provided by the Russian Integrated Mining Chemical Company, was tested at Pacific Northwest National Laboratory (PNNL) to observe its ability to mobilize settled solids. Based on the results of this demonstration, ORNL and DOE staff determined that a modified pulsating mixer pump would meet project needs for bulk mobilization of Gunite tank sludge prior to deployment of other retrieval systems. The deployment of this device is expected to significantly reduce the costs of operation and maintenance of more expensive retrieval systems. The functions and requirements presented here were developed by evaluating the results and recommendations that resulted from the pulsating mixer pump demonstration at PNNL, and by coupling this with the remediation needs identified by staff at ORNL involved with the remediation of the Gunite and Associated Tanks

  11. FUNCTIONS AND REQUIREMENTS FOR RUSSIAN PULSATING MONITOR DEPLOYMENT IN THE GUNITE AND ASSOCIATED TANKS AT OAK RIDGE NATIONAL LABORATORY

    Energy Technology Data Exchange (ETDEWEB)

    Thomas Albert

    1999-01-01

    This document provides functions and requirements to support deployment of pulsating mixer pump technology in the Oak Ridge National Laboratory (ORNL) Gunite and Associated Tanks to mobilize and mix the settled sludge and solids in these tanks. In FY 1998 pulsating mixer pump technology, a jet mixer powered by a reciprocating air supply, was selected for FY 1999 deployment in one of the GAAT tanks to mobilize settled solids. Pulsating mixer pump technology was identified in FY 1996 during technical exchanges between the US Department of Energy (DOE) Tanks Focus Area Retrieval and Closure program, the DOE Environmental Management International Programs, and delegates from Russia as a promising technology that could be implemented in the US. The pulsating mixer pump technology, provided by the Russian Integrated Mining Chemical Company, was tested at Pacific Northwest National Laboratory (PNNL) to observe its ability to mobilize settled solids. Based on the results of this demonstration, ORNL and DOE staff determined that a modified pulsating mixer pump would meet project needs for bulk mobilization of Gunite tank sludge prior to deployment of other retrieval systems. The deployment of this device is expected to significantly reduce the costs of operation and maintenance of more expensive retrieval systems. The functions and requirements presented here were developed by evaluating the results and recommendations that resulted from the pulsating mixer pump demonstration at PNNL, and by coupling this with the remediation needs identified by staff at ORNL involved with the remediation of the Gunite and Associated Tanks.

  12. Project Execution Plan for Project W-211 Initial Tank Retrieval Systems (ITRS)

    International Nuclear Information System (INIS)

    This Project Execution Plan documents the methodology for managing Project W-211. Project W-211, Initial Tank Retrieval Systems (ITRS), is a fiscal year 1994 Major Systems Acquisition that will provide systems for retrieval of radioactive wastes from selected double-shell tanks (DST). The contents of these tanks are a combination of supernatant liquids and settled solids. To retrieve waste from the tanks, it is first necessary to mix the liquid and solids prior to transferring the slurry to alternative storage or treatment facilities. The ITRS will provide systems to mobilize the settled solids and transfer the wastes out of the tanks. In so doing, ITRS provides feed for the future waste treatment plant, allows for consolidation of tank solids to manage space within existing DST storage capacity, and supports continued safe storage of tank waste. The ITRS scope has been revised to include waste retrieval systems for tanks AP-102, AP-104, AN-102, AN-103, AN-104, AN-105, AY-102, AZ-102, and SY-102. This current tank selection and sequence provides retrieval systems supporting the River Protection Project (RF'P) Waste Treatment Facility and sustains the ability to provide final remediation of several watch list DSTs via treatment. The ITRS is configured to support changing program needs, as constrained by available budget, by maintaining the flexibility for exchanging tanks requiring mixer pump-based retrieval systems and shifting the retrieval sequence. Preliminary design was configured such that an adequate basis exists for initiating Title II design of a mixer pump-based retrieval system for any DST. This Project Execution Plan (PEP), derived from the predecessor Project Management Plan, documents the methodology for managing the ITRS, formalizes organizational responsibilities and interfaces, and identifies project requirements such as change control, design verification, systems engineering, and human factors engineering

  13. Project Management Plan for Initial Tank Retrieval Systems, Project W-211

    International Nuclear Information System (INIS)

    Project W-211, Initial Tank Retrieval Systems (ITRS), is a fiscal year 1994 Major Systems Acquisition that will provide systems for retrieval of radioactive wastes from selected double-shell tanks (DST). The contents of these tanks are a combination of supernatant liquids and settled solids. To retrieve waste from the tanks, it is first necessary to mix the liquid and solids prior to transferring the slurry to alternative storage or treatment facilities. The ITRS will provide systems to mobilize the settled solids and transfer the wastes out of the tanks. In so doing, ITRS provides feed for future processing plants, allows for consolidation of tank solids to manage space within existing DST storage capacity, and supports continued safe storage of tank waste. The ITRS scope has been revised to include waste retrieval systems for tanks AP-102, AP-104, AP-108, AN-103, AN-104, AN-105, AY-102, AZ-102, and SY-102. This current tank selection and sequence provides retrieval systems supporting the Privatized waste processing plant and sustains the ability to provide final remediation of several watch list DSTs via treatment. The ITRS is configured to support changing program needs, as constrained by available budget, by maintaining the flexibility for exchanging tanks requiring mixer pump-based retrieval systems and shifting the retrieval sequence. Preliminary design was configured such that an adequate basis exists for initiating Title II design of a mixer pump based retrieval system for any DST. This Project Management Plan (PMP) documents the methodology for managing the ITRS, formalizes organizational responsibilities and interfaces, and identifies project requirements such as change control, design verification, systems engineering, and human factors engineering

  14. Effects of intermittent aeration on pollutants removal in subsurface wastewater infiltration system.

    Science.gov (United States)

    Pan, Jing; Fei, Hexin; Song, Siyu; Yuan, Fang; Yu, Long

    2015-09-01

    In this study, the pollutant removal performances in two pilot-scale subsurface wastewater infiltration systems (SWISs) with and without intermittent aeration were investigated. Matrix oxidation reduction potential (ORP) results showed that intermittent aeration well developed aerobic conditions in upper matrix and anoxic or anaerobic conditions in the subsequent sections, which resulted in high NH4(+)-N and TN removal. Moreover, intermittent aeration increased removal rates of COD and TP. Microbial populations and enzyme activities analysis proved that intermittent aeration not only obviously boosted the growth and reproduction of bacteria, fungus, actinomyces, nitrifying bacteria and denitrifying bacteria, but also successfully increased nitrate reductase (NR) and nitrite reductase (NIR) in the depth of 80 and 110 cm. The results suggest that the intermittent aeration could be a widespread research and application strategy for achieving the high removal performance in SWISs. PMID:26004389

  15. EXPERIMENTAL INVESTIGATION ON SOUND SPEED PROPAGATING THROUGH HIGH SPEED AERATED FLOW IN OPEN CHANNEL

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An experiment concerning the sound propaga-tion in aerated open channel flow was designed and conductedin a variable slope chute. The acquisition of sound data wasdone by the hydro-phones installed into the bottom wall of thechute. The data were analyzed and processed by the tape re-corder and a 3562A analyzer. The primary experimetal resultsindicated that the sound speed in aerated flow is varied with the air concentration and highly lower than each of the soundspeed in pure water or air. As released by the derived theoryformula, the minimum sound of 24m/s in aerated flow hap-pened when the air concentration achieved to 50%. This resultshows that the compressibility of high speed aerated flowshould be considered when the air concentration is near to50%. A criterion of compressibility of high speed aerated flowwas also giv. En in this paper.

  16. Influence of aeration–homogenization system in stirred tank bioreactors, dissolved oxygen concentration and pH control mode on BHK-21 cell growth and metabolism

    OpenAIRE

    Núñez, Eutimio Gustavo Fernández; Leme, Jaci; de Almeida Parizotto, Letícia; Chagas, Wagner Antonio; de Rezende, Alexandre Gonçalves; da Costa, Bruno Labate Vale; Monteiro, Daniela Cristina Ventini; Boldorini, Vera Lucia Lopes; Jorge, Soraia Attie Calil; Astray, Renato Mancini; Pereira, Carlos Augusto; Caricati, Celso Pereira; Tonso, Aldo

    2013-01-01

    This work focused on determining the effect of dissolved oxygen concentration (DO) on growth and metabolism of BHK-21 cell line (host cell for recombinant proteins manufacturing and viral vaccines) cultured in two stirred tank bioreactors with different aeration-homogenization systems, as well as pH control mode. BHK-21 cell line adapted to single-cell suspension was cultured in Celligen without aeration cage (rotating gas-sparger) and Bioflo 110, at 10, 30 and 50 % air saturation (impeller f...

  17. F-AREA PUMP TANK 1 MIXING ANALYSIS

    International Nuclear Information System (INIS)

    The F-area pump tanks are used to transfer supernate, sludge, and other materials. In any transfer, the solution must stay well mixed without allowing particulate matter to settle out of the liquid and, thus, accumulate in the bottom of the pump tank. Recently, the pulse jet mixing in F-area Pump Tank 1 (FPT1) has been decommissioned. An analysis of the liquid transfer through FPT1 has been performed using computational fluid dynamics (CFD) methods to assess whether or not the velocities throughout the tank will remain high enough to keep all particulate suspended using only transfer and recirculation pumps. The following paragraph is an abbreviated synopsis of the transfer procedure for FPT1 (1, 2). Prior to a transfer, FPT1 begins to be filled with inhibited water through the inlet transfer line (TI). When the tank liquid level reaches 52.5 inches above the absolute tank bottom, the recirculation pump (RI and RO) is activated. At a tank liquid level of 72.5 inches above the absolute tank bottom, the outlet transfer line (TO) is activated to reduce the liquid level in FPT1 and transfer inhibited water to H-area Pump Tank 7 (HPT7). The liquid level is reduced down to 39.5 inches, with an allowable range from 37.5 to 41.5 inches above the absolute tank bottom. HPT7 goes through a similar procedure as FPT1 until both have tank liquid levels of approximately 39.5 inches above the absolute tank bottom. The transfer of inhibited water continues until a steady-state has been reached in both pump tanks. At this point, the supernate/sludge transfer begins with a minimum flow rate of 70 gpm and an average flow rate of 150 gpm. After the transfer is complete, the pump tanks (both FPT1 and HPT7) are pumped down to between 20.5 and 22.5 inches (above absolute bottom) and then flushed with 25,000 gallons of inhibited water to remove any possible sludge heal. After the flushing, the pump tanks are emptied. Note that the tank liquid level is measured using diptubes. Figure 2

  18. Production of xylanolytic enzymes by Aspergillus terricola in stirred tank and airlift tower loop bioreactors.

    Science.gov (United States)

    Michelin, Michele; Polizeli, Maria de Lourdes Teixeira de Moraes; Silva, Daniel Pereira da; Ruzene, Denise Santos; Vicente, António Augusto; Jorge, João Atílio; Terenzi, Héctor Francisco; Teixeira, José António

    2011-12-01

    Fungi producing high xylanase levels have attracted considerable attention because of their potential industrial applications. Batch cultivations of Aspergillus terricola fungus were evaluated in stirred tank and airlift bioreactors, by using wheat bran particles suspended in the cultivation medium as substrate for xylanase and β-xylosidase production. In the stirred tank bioreactor, in physical conditions of 30°C, 300 rpm, and aeration of 1 vvm (1 l min⁻¹), with direct inoculation of fungal spores, 7,475 U l⁻¹ xylanase was obtained after 36 h of operation, remaining constant after 24 h. In the absence of air injection in the stirred tank reactor, limited xylanase production was observed (final concentration 740 U l⁻¹). When the fermentation process was realized in the airlift bioreactor, xylanase production was higher than that observed in the stirred tank bioreactor, being 9,265 U l⁻¹ at 0.07 vvm (0.4 l min⁻¹) and 12,845 U l⁻¹ at 0.17 vvm (1 l min⁻¹) aeration rate. PMID:21626207

  19. 1/12-Scale scoping experiments to characterize double-shell tank slurry uniformity: Test plan

    International Nuclear Information System (INIS)

    Million gallon double-shell tanks (DSTs) at Hanford are used to store transuranic, high-level, and low-level wastes. These wastes generally consist of a large volume of salt-laden solution covering a smaller volume of settled sludge primarily containing metal hydroxides. These wastes will be retrieved and processed into immobile waste forms suitable for permanent disposal. The current retrieval concept is to use submerged dual-nozzle pumps to mobilize the settled solids by creating jets of fluid that are directed at the tank solids. The pumps oscillate, creating arcs of high-velocity fluid jets that sweep the floor of the tank. After the solids are mobilized, the pumps will continue to operate at a reduced flow rate sufficient to maintain the particles in a uniform suspension. The objectives of these 1/12-scale scoping experiments are to determine how Reynolds number, Froude number, and gravitational settling parameter affect the degree of uniformity achieved during jet mixer pump operation in the full-scale double-shell tanks; develop linear models to predict the degree of uniformity achieved by jet mixer pumps operating in the full-scale double-shell tanks; apply linear models to predict the degree of uniformity that will be achieved in tank 241-AZ-101 and determine whether contents of that tank will be uniform to within ± 10% of the mean concentration; and obtain experimental concentration and jet velocity data to compared with the TEMPEST computational and modeling predictions to guide further code development

  20. Submerged culture of phellinus linteus in a stirred tank fermenter and an airlift fermenter

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Keun Ho; Lee, Chang Woo [Dept. of Chemical Engineering, Hanbat National University, Taejeon (Korea)

    2000-04-01

    In this study, to choose a suitable bioreactor type for the mass culture of Phellinus linteus mycelium, we cultured phellinus linteus mycelium using a stirred tank fermenter and an airlift fermenter and compared the performances of the two fermenters. The effects of aeration rate and agitation speed on the culture of Phellinus linteus mycelium were also investigated in the ranges of 1-4L/min, 200-300 rpm, respectively. For the Batch submerged culture, the dry weight of mycelium, pH, and dissolved oxygen concentration changed in four steps, respectively. But the periods of same steps were not consistent with each other. With an increase in aeration rate, the final dry weight of mycelium, dissolved oxygen concentration and pH value until the third step of pH change were increased. As the time increased, the concentration of glucose decreased. However, the effects of aeration rate and agitation speed on the variation of glucose concentration were negligible. The maximum final dry weight of mycelium was obtained when agitation speed was 300 rpm. The dissolved oxygen concentration was increased with agitation speed. The dry weight of mycelium and dissolved oxygen concentration in the continuous stirred tank fermenter were larger than them those in the airlift fermenter. 27 refs., 9 figs.

  1. Quantitative detection of settled dust over green canopy

    Science.gov (United States)

    Brook, Anna

    2016-04-01

    The main task of environmental and geoscience applications are efficient and accurate quantitative classification of earth surfaces and spatial phenomena. In the past decade, there has been a significant interest in employing hyperspectral unmixing in order to retrieve accurate quantitative information latent in hyperspectral imagery data. Recently, the ground-truth and laboratory measured spectral signatures promoted by advanced algorithms are proposed as a new path toward solving the unmixing problem of hyperspectral imagery in semi-supervised fashion. This paper suggests that the sensitivity of sparse unmixing techniques provides an ideal approach to extract and identify dust settled over/upon green vegetation canopy using hyperspectral airborne data. Atmospheric dust transports a variety of chemicals, some of which pose a risk to the ecosystem and human health (Kaskaoutis, et al., 2008). Many studies deal with the impact of dust on particulate matter (PM) and atmospheric pollution. Considering the potential impact of industrial pollutants, one of the most important considerations is the fact that suspended PM can have both a physical and a chemical impact on plants, soils, and water bodies. Not only can the particles covering surfaces cause physical distortion, but particles of diverse origin and different chemistries can also serve as chemical stressors and cause irreversible damage. Sediment dust load in an indoor environment can be spectrally assessed using reflectance spectroscopy (Chudnovsky and Ben-Dor, 2009). Small amounts of particulate pollution that may carry a signature of a forthcoming environmental hazard are of key interest when considering the effects of pollution. According to the most basic distribution dynamics, dust consists of suspended particulate matter in a fine state of subdivision that are raised and carried by wind. In this context, it is increasingly important to first, understand the distribution dynamics of pollutants, and

  2. Grout performance in support of in situ stabilization/solidification of the GAAT tank sludges

    Energy Technology Data Exchange (ETDEWEB)

    Spence, R. D. [Oak Ridge National Lab., TN (United States); Kauschinger, J. L. [Ground Environmental Services, Inc., Alpharetta, GA (United States)

    1997-05-01

    The Gunite{trademark} and associated tanks (GAATs) were constructed at ORNL between 1943 and 1951 and were used for many years to collect radioactive and chemical wastes. These tanks are currently inactive. Varying amounts of the sludge were removed and disposed of through the Hydrofracture Program. Thus, some tanks are virtually empty, while others still contain significant amounts of sludge and supernatant. In situ grouting of the sludges in the tanks using multi-point injection (MPI{trademark}), a patented, proprietary technique, is being investigated as a low-cost alternative to (1) moving the sludges to the Melton Valley Storage Tanks (MVSTs) for later solidification and disposal, (2) ex situ grouting of the sludges followed by either disposal back in the tanks or containerizing and disposal elsewhere, and (3) vitrification of the sludges. The paper discusses the chemical characteristics of the GAATs and the type of chemical surrogate that was used during the leachability tests. T his is followed by the experimental work, which, consisted of scope testing and sensitivity testing. The scope testing explored the rheology of the proposed jetting slurries and the settling properties of the proposed grouts using sand-water mixes for the wet sludge. After establishing a jetting slurry and grout with an acceptable rheology and settling properties, the proposed in situ grout formulation was subjected to sensitivity testing for variations in the formulation.

  3. Grout performance in support of in situ stabilization/solidification of the GAAT tank sludges

    International Nuclear Information System (INIS)

    The Gunite trademark and associated tanks (GAATs) were constructed at ORNL between 1943 and 1951 and were used for many years to collect radioactive and chemical wastes. These tanks are currently inactive. Varying amounts of the sludge were removed and disposed of through the Hydrofracture Program. Thus, some tanks are virtually empty, while others still contain significant amounts of sludge and supernatant. In situ grouting of the sludges in the tanks using multi-point injection (MPI trademark), a patented, proprietary technique, is being investigated as a low-cost alternative to (1) moving the sludges to the Melton Valley Storage Tanks (MVSTs) for later solidification and disposal, (2) ex situ grouting of the sludges followed by either disposal back in the tanks or containerizing and disposal elsewhere, and (3) vitrification of the sludges. The paper discusses the chemical characteristics of the GAATs and the type of chemical surrogate that was used during the leachability tests. This is followed by the experimental work, which, consisted of scope testing and sensitivity testing. The scope testing explored the rheology of the proposed jetting slurries and the settling properties of the proposed grouts using sand-water mixes for the wet sludge. After establishing a jetting slurry and grout with an acceptable rheology and settling properties, the proposed in situ grout formulation was subjected to sensitivity testing for variations in the formulation

  4. Quantitative detection of settled dust over green canopy

    Science.gov (United States)

    Brook, Anna

    2016-04-01

    The main task of environmental and geoscience applications are efficient and accurate quantitative classification of earth surfaces and spatial phenomena. In the past decade, there has been a significant interest in employing hyperspectral unmixing in order to retrieve accurate quantitative information latent in hyperspectral imagery data. Recently, the ground-truth and laboratory measured spectral signatures promoted by advanced algorithms are proposed as a new path toward solving the unmixing problem of hyperspectral imagery in semi-supervised fashion. This paper suggests that the sensitivity of sparse unmixing techniques provides an ideal approach to extract and identify dust settled over/upon green vegetation canopy using hyperspectral airborne data. Atmospheric dust transports a variety of chemicals, some of which pose a risk to the ecosystem and human health (Kaskaoutis, et al., 2008). Many studies deal with the impact of dust on particulate matter (PM) and atmospheric pollution. Considering the potential impact of industrial pollutants, one of the most important considerations is the fact that suspended PM can have both a physical and a chemical impact on plants, soils, and water bodies. Not only can the particles covering surfaces cause physical distortion, but particles of diverse origin and different chemistries can also serve as chemical stressors and cause irreversible damage. Sediment dust load in an indoor environment can be spectrally assessed using reflectance spectroscopy (Chudnovsky and Ben-Dor, 2009). Small amounts of particulate pollution that may carry a signature of a forthcoming environmental hazard are of key interest when considering the effects of pollution. According to the most basic distribution dynamics, dust consists of suspended particulate matter in a fine state of subdivision that are raised and carried by wind. In this context, it is increasingly important to first, understand the distribution dynamics of pollutants, and

  5. Hanford tanks initiative plan

    International Nuclear Information System (INIS)

    Abstract: The Hanford Tanks Initiative (HTI) is a five-year project resulting from the technical and financial partnership of the U.S. Department of Energy's Office of Waste Management (EM-30) and Office of Science and Technology Development (EM-50). The HTI project accelerates activities to gain key technical, cost performance, and regulatory information on two high-level waste tanks. The HTI will provide a basis for design and regulatory decisions affecting the remainder of the Tank Waste Remediation System's tank waste retrieval Program

  6. Hanford tanks initiative plan

    Energy Technology Data Exchange (ETDEWEB)

    McKinney, K.E.

    1997-07-01

    Abstract: The Hanford Tanks Initiative (HTI) is a five-year project resulting from the technical and financial partnership of the U.S. Department of Energy`s Office of Waste Management (EM-30) and Office of Science and Technology Development (EM-50). The HTI project accelerates activities to gain key technical, cost performance, and regulatory information on two high-level waste tanks. The HTI will provide a basis for design and regulatory decisions affecting the remainder of the Tank Waste Remediation System`s tank waste retrieval Program.

  7. Liquid metal storage tank

    International Nuclear Information System (INIS)

    The present invention concerns a liquid metal storage tank used for an FBR type reactor plant. It comprises a tank main body disposed in a pit chamber, a sealing tub disposed at an upper outer circumferential surface of the tank main body, a roof portion which closes the opening a the upper end of the pit chamber, a sealing partitioning cylinder suspended from the lower surface of the roof and having its lower end extended to the inside of the tub and a sealing liquid metal filled in the tub. The tank main body is kept at a high temperature by the liquid metal while the roof in the upper portion of the pit chamber is kept at a low temperature. Further, since the tank main body and the inside of the pit chamber are sealed by the sealing partitioning cylinder, no large thermal stresses are caused to the wall of the tank main body. Even if hydrogen gases are generated in the tank main body, since they can be released to the inside of the pit chamber, the integrity of the tank can be maintained, even if abrupt pressure elevation is caused in the tank main body. (I.S.)

  8. Fuel reprocessing tank

    International Nuclear Information System (INIS)

    A tank of the present invention for spent fuels comprises a stainless steel tank main body for storing a highly corrosive dissolving solution, a steam jet pump disposed to the inside of the tank main body for transferring the dissolving solution to the outside of the tank main body and pipelines connecting them. With such a constitution, abnormal abrasion and drag of mechanical parts are less caused. In addition, a cleaning nozzle and a cleaning liquid pipeline which eliminates clogging of a sucking port of the steam jet pump if clogging is caused by sludges are disposed thereby enabling to avoid possibility of clogging. (T.M.)

  9. Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

    International Nuclear Information System (INIS)

    The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM

  10. Aeration-Controlled Formation of Acid in Heterolactic Fermentations

    DEFF Research Database (Denmark)

    Adler-Nissen, Jens

    1994-01-01

    Controlled aeration of Leuconostoc mesenteroides was studied as a possible mechanism for control of the formation of acetic acid, a metabolite of major influence on the taste of lactic fermented foods. Fermentations were carried out in small scale in a medium in which growth was limited by the...... buffer capacity only. Ethanol and acetic acid formed during the fermentation were analyzed by rapid head space gas chromatography, and the ratio of the molar concentrations of these two volatiles quantitatively predicted the balance between the formation of acetic acid and lactic acid. The oxygen...... concentration during the fermentations decreased rapidly to zero, meaning that oxygen transfer was limited by the volumetric oxygen transfer rate, k1aC*. A linear correlation between k1aC* and the quantity of acetic acid produced was established, and it is suggested that such oxygenated heterolactic...

  11. DOMESTIC WASTEWATER PURIFICATION IN UPFLOW BIOFILM SYSTEM WITH DIFFUSED AERATION

    Directory of Open Access Journals (Sweden)

    A.Mesdaghinia

    1984-08-01

    Full Text Available The objective of this research was to conduct a bench scale study of fixed activated sludge treating domestic sewage. Two different units employing diffused aeration with plastic and aluminum media were studied in four separate phases. Data indicated that the system could produce a high quality effluent without any requirements for sludge recycling through the system. Suspended solids concentrations of 3-6 mg/1, BOD5 concentrations of 4-12 mg/1 and COD concentrations of 35-45 mg/1 were found in the effluent with wastewater retentions ranging from 3-15 hours, whereas an indication of nitrification was observed in higher detention periods. As far as the type of media was concerned, the plastic and aluminum media did not differ significantly once the microbes had grown on the media.

  12. Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, D., E-mail: daniele.ferretti@unipr.it [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, P.co Area delle Scienze 181/A, 43124 Parma (Italy); Michelini, E. [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, P.co Area delle Scienze 181/A, 43124 Parma (Italy); Rosati, G. [Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano (Italy)

    2015-01-15

    The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM.

  13. Modeling of damage due to shrinkage in autoclaved aerated concrete

    Czech Academy of Sciences Publication Activity Database

    Koudelka, T.; Kruis, J.; Sysala, Stanislav; Vokáč, M.

    Vol. 1648. Melville, NY: AIP Publishing, 2015 - (Simos, T.; Tsitouras, C.), 090012-1-090012-4. (AIP Conference Proceedings. 1648). ISBN 978-0-7354-1287-3. ISSN 0094-243X. [International Conference on Numerical Analysis and Applied Mathematics 2014 (ICNAAM-2014). Rhodes (GR), 22.09.2014-28.09.2014] R&D Projects: GA ČR GA13-18652S Institutional support: RVO:68145535 Keywords : autoclaved aerated concrete * isotropic damage * shrinkage * coupled problems Subject RIV: JM - Building Engineering http://scitation.aip.org/docserver/fulltext/aip/proceeding/aipcp/1648/10.1063/1.4912400/1.4912400.pdf?expires=1427792299&id=id&accname=guest&checksum=6AE655B2B43B3EDCD5D3CA15B4C56CB7

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

    DEFF Research Database (Denmark)

    Sorrell, Brian Keith

    Permanent and indefinite survival of plants in flooded soils depends primarily on adaptations that increase the supply of oxygen to tissues in anoxic soil and water, usually associated with features such as (i) increased tissue porosity, (ii) changes in tissue permeability to gases, and (iii...... support many species which have root aeration adaptations but are otherwise unspecialised for aquatic life. Permanent standing water is a much greater challenge for plants, and survival here is restricted to species with special adaptations to their oxygen transport physiology such as the development...... differing in flooding tolerance. Maintaining species diversity in managed wetlands therefore involves hydrological conditions suitable for a variety of plants that differ in their flooding tolerance. The shallowest areas of wetlands, in which soils are waterlogged but there is little standing water, can...

  15. Nitrogen and phosphorus removal under intermittent aeration conditions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A practice wastewater treatment plant was operated usingintermittent aeration activated sludge process to enhancebiological nitrogen and phosphorus removal. When the influentconcentrations of CODCr, BOD5, TN, TP, NH3-N, TKN, and SS varied ina range of 207.5-1640 mg/L, 61.8-637 mg/L, 28.5-75.6 mg/L, 4.38-20.2 mg/L, 13.6-31.9 mg/L, 28.5-75.6 mg/L, and 111-1208 mg/L, theeffluent means were less than 50 mg/L, 20 mg/L, 5 mg/L, 1.0 mg/L,5 mg/L, 10 mg/L, and 20 mg/L, respectively. Based on a long time ofoperating results, this process is very suitable for nutrientbiological removal for treating the municipal wastewater thosewater characteristics are similar as that of the Songjiang Municipal Waste water Treatment plant(SJMWTP).

  16. Visual evaluation of effective cleaning radius in model jet-agitated tank

    International Nuclear Information System (INIS)

    Suspension of monosodium titanate (MST) and sludge in high level waste (HLW) tanks at Savannah River Site (SRS) is needed prior to processing of the salt solution (containing actinides, Sr-90, and Cs-137) from the supernate and the dissolved salt cake. One type III tank model, including cooling coils, was fabricated and used to carry out cost effective evaluation of jet mixing of MST and simulant sludge in surrogate salt solution. The model tank has a diameter of 0.3 m (1 ft). Experimental work was carried out utilizing five different sludge/MST mixtures in surrogate salt solution. The examined solutions included 5% wt sludge, 5% wt 4:1 sludge/MST, 5% wt 2:1 sludge/MST, 5% wt 1:1 sludge/MST, and 5% wt MST. The progress of the effective cleaning radius (ECR) formation was monitored during the mixing and suspension processes with and without the presence of cooling coils and at several pumping flow rates and nozzle orientations. Digital photographs of the bottom of the tank were analyzed and the ECR was measured at different pumping flow rate and nozzle orientation. It was found that it took 20 to 30 minutes in order to reach a fully developed ECR at the bottom of the tank. A qualitative analysis of the images taken for the fully developed ECR (at nozzle angles of 0 deg., 45 deg., and 90 deg. from the centerline of the tank) indicated that two counter-rotating eddies took place in the tank, resulting in full suspension of the sludge and MST except for two islands (spots) of settling sludge and MST particles. These islands of settling sludge and MST vary in size and location depending on the pump flow rate and the angle of the nozzle from the tank centerline. The presence of cooling coils in the tank hindered the suspension process and resulted in an undeveloped ECR even at high flow rates. (authors)

  17. The importance of aeration strategy in fuel alcohol fermentations contaminated with Dekkera/Brettanomyces yeasts.

    Science.gov (United States)

    Abbott, D A; Ingledew, W M

    2005-11-01

    Whole corn mash fermentations infected with industrially-isolated Brettanomyces yeasts were not affected even when viable Brettanomyces yeasts out-numbered Saccharomyces yeasts tenfold at the onset of fermentation. Therefore, aeration, a parameter that is pivotal to the physiology of Dekkera/Brettanomyces yeasts, was investigated in mixed culture fermentations. Results suggest that aeration strategy plays a significant role in Dekkera/Brettanomyces-mediated inhibition of fuel alcohol fermentations. Although growth of Saccharomyces cerevisiae was not impeded, mixed culture fermentations aerated at rates of > or =20 ml air l(-1) mash min(-1) showed decreased ethanol yields and an accumulation of acetic acid. The importance of aeration was examined further in combination with organic acid(s). Growth of Saccharomyces occurred more rapidly than growth of Brettanomyces yeasts in all conditions. The combination of 0.075% (w/v) acetic acid and contamination with Brettanomyces TK 1404W did not negatively impact the final ethanol yield under fermentative conditions. Aeration, however, did prove to be detrimental to final ethanol yields. With the inclusion of aeration in the control condition (no organic acid stress) and in each fermentation containing organic acid(s), the final ethanol yields were decreased. It was therefore concluded that aeration strategy is the key parameter in regards to the negative effects observed in fuel alcohol fermentations infected with Dekkera/Brettanomyces yeasts. PMID:15782293

  18. Composting of tobacco plant waste by manual turning and forced aeration system

    Directory of Open Access Journals (Sweden)

    Nonglak Saithep

    2009-05-01

    Full Text Available The efficiency of tobacco plant waste composting, by the manual turning and the forced aeration system, was compared. Tobacco plant waste, cow manure, urea fertiliser, and a compost inoculum mixture at a 100:10:0.2:0.01 ratio respectively, with 60% (w/v moisture content, were set up in piling forms. The piles of the manual turning system were provided with turning aeration by hand at intervals of 7 days during the composting process. For the forced aeration system, each pile was aerated by a 3-HP air pump with a flow rate of 19 litres min-1 for 15 minutes every morning and evening. The completely randomised design of turned and force-aerated piles was performed in triplicate. The composting activity of both systems during the composting period was measured by several parameters: temperature, pH, moisture content, C/N ratio, growth of microorganisms, cellulase activity, and nicotine degradation in the set-up piles. Both systems had similar temperature, pH, and moisture content conditions in the piles during the composting process. However, the forced aeration system was more advantageous for the growth of mesophilic and thermophilic microorganisms, for cellulase activity from cellulase-producing microorganisms, and for nicotine degradation, when compared to the manual turning system. In conclusion, the forced aeration system was more efficient than the manual turning system in composting and is a viable alternative method for the composting process.

  19. Clustering of settling charged particles in turbulence: theory and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lu Jiang; Nordsiek, Hansen; Shaw, Raymond A, E-mail: rashaw@mtu.edu [Department of Physics, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)

    2010-12-15

    Atmospheric clouds, electrosprays and protoplanetary nebula (dusty plasma) contain electrically charged particles embedded in turbulent flows, often under the influence of an externally imposed, approximately uniform gravitational or electric force. We have developed a theoretical description of the dynamics of such systems of charged, sedimenting particles in turbulence, allowing radial distribution functions (RDFs) to be predicted for both monodisperse and bidisperse particle size distributions. The governing parameters are the particle Stokes number (particle inertial time scale relative to turbulence dissipation time scale), the Coulomb-turbulence parameter (ratio of Coulomb 'terminal' speed to the turbulence dissipation velocity scale) and the settling parameter (the ratio of the gravitational terminal speed to the turbulence dissipation velocity scale). The theory is compared to measured RDFs for water particles in homogeneous, isotropic air turbulence. The RDFs are obtained from particle positions measured in three dimensions using digital holography. The measurements verify the general theoretical expression, consisting of a power law increase in particle clustering due to particle response to dissipative turbulent eddies, modulated by an exponential electrostatic interaction term. Both terms are modified as a result of the gravitational diffusion-like term, and the role of 'gravity' is explored by imposing a macroscopic uniform electric field to create an enhanced, effective gravity.

  20. Hydrodynamic characteristics of high speed settling clarifiers by radiotracer method

    International Nuclear Information System (INIS)

    Results achieved in the evaluation of two high-speed settling cane juice Clarifiers, one denominated ICINAZ The Express and the other one a modified SRI, both located at the sugar factory Orlando Gonzalez employing the well established radiotracer method (Tc-99m) are presented Several trials performed simultaneously at the two Clarifiers demonstrated that the modified SRI was capable to assimilate the whole flow capacity of the factory with adequate characteristic of the pattern flux and residence time in the environment of 1 hour. In the other side, ICINAZ The Express Clarifier could only work at relative low flow capacity of the factory with residence time closely to the two hours and achieving occasionally a pattern flux seriously affected by fluctuations in the milling process. The non-availability of a flow meter did not allow to extract more information related to some pattern flux anomalies, nevertheless, the radiotracer method was able to detect certain differences between the two clear juice outlet of the modified SRI Clarifier, probably due some problems in the construction of this equipment. This fact so as other goals achieved in this work, show once more the potentiality of the radiotracer method for this type of study related to the hydrodynamic characteristics of industrial facilities. (Author)

  1. Clustering of settling charged particles in turbulence: theory and experiments

    International Nuclear Information System (INIS)

    Atmospheric clouds, electrosprays and protoplanetary nebula (dusty plasma) contain electrically charged particles embedded in turbulent flows, often under the influence of an externally imposed, approximately uniform gravitational or electric force. We have developed a theoretical description of the dynamics of such systems of charged, sedimenting particles in turbulence, allowing radial distribution functions (RDFs) to be predicted for both monodisperse and bidisperse particle size distributions. The governing parameters are the particle Stokes number (particle inertial time scale relative to turbulence dissipation time scale), the Coulomb-turbulence parameter (ratio of Coulomb 'terminal' speed to the turbulence dissipation velocity scale) and the settling parameter (the ratio of the gravitational terminal speed to the turbulence dissipation velocity scale). The theory is compared to measured RDFs for water particles in homogeneous, isotropic air turbulence. The RDFs are obtained from particle positions measured in three dimensions using digital holography. The measurements verify the general theoretical expression, consisting of a power law increase in particle clustering due to particle response to dissipative turbulent eddies, modulated by an exponential electrostatic interaction term. Both terms are modified as a result of the gravitational diffusion-like term, and the role of 'gravity' is explored by imposing a macroscopic uniform electric field to create an enhanced, effective gravity.

  2. Time to settle the tax issue for the resource industry

    International Nuclear Information System (INIS)

    This report presented a brief comment on policy issues concerning taxes imposed on the resource industry. It was suggested that if the resource industry in Canada is to remain competitive beyond the current boom, the federal government should provide a more stable tax environment for investment in the longer run. With the current internationally competitive tax rates and high neutrality among energy sectors, there is presently a unique opportunity to settle this issue and to improve the tax system as a whole. It was suggested that the federal corporate income tax rate on resource profits should be reduced from 28 per cent to 21 per cent as it is in other sectors. It was also suggested that the resource allowance should be replaced with deductibility for resource royalties as payment for the cost of using provincially owned resources. This report also described other changes that could be implemented to improve the tax system and to enhance the competitiveness of the resource sector. It was noted that the changes could result in a single corporate income tax rate on all industrial activities by 2005

  3. [Removal nitrogen of integrated vertical-flow constructed wetland under aeration condition].

    Science.gov (United States)

    Tao, Min; He, Feng; Xu, Dong; Zhou, Qiao-Hong; Liang, Wei; Chen, Shui-Ping; Wu, Zhen-Bin

    2011-03-01

    Oxygen is an important limit factor of nitrogen removal in constructed wetlands, so it is the key point for improving nitrogen removal efficiency of constructed wetlands that the optimization of oxygen distribution within wetlands. Therefore, oxygen status, nitrogen removal and purification mechanism of integrated vertical-flow constructed wetland (IVCW) under aeration condition in summer and winter have been studied. The results showed that both oxygen levels and aerobic zones were increased in the wetland substrates. The area of oxic zone I (expressing with depth) extended from 22 cm, 17 cm to 53 cm, 44 cm, in summer and winter, respectively. The electric potential (Eh) profiling demonstrated that artificial aeration maintained the pattern of sequential oxic-anoxic-oxic (O-A-O) redox zones within the aerated IVCW in winter, while only two oxic-anoxic (O-A) zones were present inside the non-aerated IVCW in the cold season. The decomposition of organic matter and nitrification were obviously enhanced by artificial aeration since the removal efficiency of COD, TN and NH4(+) -N were increased by 12.2%, 6.9% and 15.1% in winter, respectively. There was no significant accumulation of NO3(-) -N in the effluent with an aeration cycle of 8 h on and 16 h off in this experiment. Moreover, we found that oxic zone I was the main region of pollutants removal in IVCW system, and artificial aeration mainly acted to enhance the purification capacity of this oxic zone in the aerated IVCW. These results suggest that aeration is important for optimization and application of IVCW system. PMID:21634169

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

    Science.gov (United States)

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

    2016-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Abdel E. Ghaly

    2011-01-01

    Full Text Available Problem statement: The oxidation ditch system has been used to treat various types of wastewaters. Several types of aerators are used to supply the treatment process with oxygen. Among these devices, the disc aerator has certain advantages regarding foam generation over the brush and paddle type rotors, but the main disadvantages of this aerator is the limited oxygenation capacity. The main objectives of this study were to study the effects of various design parameters and system operation parameters on the oxygenation capacity of the system. Approach: A bench scale oxidation ditch system equipped with a disc aerator was used to gain better understanding of the phenomena of oxygen transfer and to study the effects of hole diameter, number of holes per disc, disc thickness, disc speed, immersion depth and number of discs on the oxygenation capacity of the system. The unsteady state method with sulphite oxidation was used to deoxygenate the water. The test involved chemical removal of dissolved oxygen from water followed by oxygenation. The power consumed was measured, the oxygen transfer coefficient was determined and both the oxygenation capacity and oxygenation efficiency were calculated. Results: The oxygen transfer coefficient was affected by the immersion depth, hole diameter, disc speed, disc thickness and number of discs, with the disc speed having the greatest effect. The results showed that three physical processes simultaneously contributed to oxygen transfer by the disc aerator: bubble aeration, eddy aeration and surface aeration. Conclusion: The use of sodium sulphite with cobalt chloride for deoxygenation of the water via the oxidation ditch was effective and the results were very consistent and repeatable. The aerator disc of 2.55 cm thickness, 1.92 cm diameter and 48 holes was found to achieve the highest oxygenation capacity. The system is anticipated to provide a broad range of oxygen transfer rates under actual conditions (23

  6. TANK 7 CHARACTERIZATION AND WASHING STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D.; Pareizs, J.; Click, D.

    2010-02-04

    A 3-L PUREX sludge sample from Tank 7 was characterized and then processed through a series of inhibited water washes to remove oxalate, sodium, and other soluble ions. Current plans use Tank 7 as one of the feed sources for Sludge Batch 7 (SB7). Tank 7 is high in oxalate due to the oxalic acid cleaning of the sludge heels from Tanks 5 and 6 and subsequent transfer to Tank 7. Ten decant and nine wash cycles were performed over a 47 day period at ambient temperature. Initially, seven decants and seven washes were completed based on preliminary estimates of the number of wash cycles required to remove the oxalate in the sludge. After reviewing the composition data, SRNL recommended the completion of 2 or 3 more decant/wash cycles to ensure all of the sodium oxalate had redissolved. In the first 7 washes, the slurry oxalate concentration was 12,300 mg/kg (69.6% oxalate removal compared to 96.1% removal of the other soluble ions). After all ten decants were complete, the slurry oxalate concentration was 3,080 mg/kg (89.2% oxalate removal compared to 99.0% of the other soluble ions). The rate of dissolution of oxalate increased significantly with subsequent washes until all of the sodium oxalate had been redissolved after seven decant/wash cycles. The measured oxalate concentrations agreed very well with LWO predictions for washing of the Tank 7 sample. Highlights of the analysis and washing of the Tank 7 sample include: (1) Sodium oxalate was detected in the as-received filtered solids. 95% of the oxalate was insoluble (undissolved) in the as-received slurry. (2) No sodium oxalate was detected in the post-wash filtered solids. (3) Sodium oxalate is the last soluble species that redissolves during washing with inhibited water. In order to significantly reduce the sodium oxalate concentration, the sludge must be highly washed, leaving the other soluble anions and cations (including sodium) very low in concentration. (4) The post-wash slurry had 1% of the soluble anions

  7. Alteration of Iron Level in Drinking Water by Aeration in Gonbad Kavoos (North East of Iran)

    OpenAIRE

    Abdoljalal Marjani; Abdoljabbar Nazari; Mostefa Seyyed

    2009-01-01

    Problem statement: In this study, removal of iron was surveyed in well water in Gonbad Kavoos City. Approach: Samples were taken before and after aeration. Concentration of iron in each sample was measured by spectrophotometer. Results: The results showed that the iron concentration was decreased after aeration (0.55, 0.44, 0.44, 0.46, 0.40 and 0.41 mg L-1) when compared with before aeration of water (0.64, 0.68, 0.65, 0.62, 0.65 and 0.67 mg L-1), respectiv...

  8. USING AERATION FOR RECARBONATION OF WATER AFTER SOFTENING BY LIME-SODA ASH

    OpenAIRE

    Laith A. Al Anaz

    2013-01-01

    Theresearch focus on using the aeration process as means for water recarbonationafter lime-soda softening. The results indicated that aeration efficientfor  recarbonation of three water sampleswith different characteristics. The lime-soda softening increased the (pH)values of the three samples to  reach(10.08,10.39,10.54) respectively. The aeration decreased these (pH) values to(8.26,8.36,8.23) respectively within (60)minutes. The depression was related tothe convert of the hydroxide and carb...

  9. Aeration effect on Spirulina platensis growth and γ-linolenic acid production

    OpenAIRE

    Srinivasa Reddy Ronda; Chandra Sekhar Bokka; Chandrika Ketineni; Binod Rijal; Prasada Rao Allu

    2012-01-01

    The influence of aeration on algal growth and gamma-linolenic acid (GLA) production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2– 2.5 vvm). Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g-1 dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vv...

  10. Improved Aeration Process - Catalytic Role Of The Iron Oxides In Arsenic Oxidation And Coprecipitation

    DEFF Research Database (Denmark)

    Kowalski, Krysztof; Søgaard, Erik Gydesen

    2013-01-01

    improved aeration process that can also help in developing better arsenic removal treatment. The results present advantages of arsenic oxidation in an aeration process in the presence of ferrihydrite surface that have been shown to adsorb arsenic simultaneously to its oxidation. The presence of...... aeration. Moreover, it was found that the adsorption rate was limited by an excess of dissolved iron, due to competition between arsenic and iron compounds for adsorption sites on iron oxyhydroxide surface. The results were obtained both in lab and pilot scale experiments, which enabled to illustrate...

  11. NUMERICAL SIMULATION OF 3-D AERATED JET BEHIND FLIP BUCKET OF OVERFLOW DAM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Aerated jet,such as the jet flow behind the flip bucket of an overflow dam, widely exists in hydraulic engineering. Up to now the model test and prototype observation have been two main methods of studying the aerated jet for a special hydraulic project. In this paper, a three-dimensional mathematical model for the aerated jet was established. It seems that the suggested model has high predictive power by comparison with the results of model tests and prototype observations, which is very useful in the study of energy dissipation and jet flow atomization.

  12. AN INVESTIGATION OF FLOW CHARACTERISTIC OF AERATED DRAG REDUCTION IN TUBE

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Under the aerated conditions of wall and top intube, the turbulent flow in the tube was measured by usingLDA. The turbulent structure of the flow field and the mech-anism of aerating drag reduction in the tube were discussed. It is shown that the energy dissipations of turbulence flow andmean flow will reduce and the flow velocity (or flow rate) willincrease by injecting mini-bubbles to the wall or top of tube,namely the effect of aerating drag reduction is attained.

  13. Numerical modelling of the strength of highly porous aerated autoclaved concrete

    Energy Technology Data Exchange (ETDEWEB)

    Schenider, T.; Greil, P. [Univ. of Erlangen-Nuernberg, Erlangen (Germany). Dept. of Materials Science; Schober, G. [Hebel AG, Fuerstenfeldbruck (Germany). Materialtechnische Entwicklung

    1998-12-31

    Highly porous building materials like aerated autoclaved concrete are characterized by low thermal conductivity and high mechanical strength, which both strongly depend on porosity. The influence of porosity distribution on the compressive strength of aerated autoclaved concrete was investigated by using finite element analysis and multiaxial Weibull theory. Calculations of failure probability of microstructures with ordered as well as random pore configurations show a dependence of compressive strength on the Weibull modulus of the matrix material and the size and arrangement of pores. The results of the calculations are compared to experimental data of aerated autoclaved concrete.

  14. Improving microalgal growth with reduced diameters of aeration bubbles and enhanced mass transfer of solution in an oscillating flow field.

    Science.gov (United States)

    Yang, Zongbo; Cheng, Jun; Lin, Richen; Zhou, Junhu; Cen, Kefa

    2016-07-01

    A novel oscillating gas aerator combined with an oscillating baffle was proposed to generate smaller aeration bubbles and enhance solution mass transfer, which can improve microalgal growth in a raceway pond. A high-speed photography system (HSP) was used to measure bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure mass-transfer coefficient and mixing time. Bubble diameter and generation time decreased with decreased aeration gas rate, decreased orifice diameter, and increased water velocity in the oscillating gas aerator. The optimized oscillating gas aerator decreased bubble diameter and generation time by 25% and 58%, respectively, compared with a horizontal tubular gas aerator. Using an oscillating gas aerator and an oscillating baffle in a raceway pond increased the solution mass-transfer coefficient by 15% and decreased mixing time by 32%; consequently, microalgal biomass yield increased by 19%. PMID:27035474

  15. Enhanced long-term organics and nitrogen removal and associated microbial community in intermittently aerated subsurface flow constructed wetlands.

    Science.gov (United States)

    Fan, Jinlin; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Wu, Haiming

    2016-08-01

    The long-term enhanced removal efficiency of organics and nitrogen in subsurface flow constructed wetlands (SSF CWs) with and without intermittent aeration for decentralized domestic wastewater was evaluated, and the function of intermittent aeration on microbial community was also investigated in this study. The high and long-term 95.6% COD, 96.1% NH4(+)-N and 85.8% TN removal efficiencies were achieved in experimental intermittently aerated SSF CW compared with non-aerated SSF CW. Aerated SSF CWs also exhibited the excellent removal performance when comparatively comparing with other strategies and techniques applied in CWs. In addition, fluorescence in situ hybridization (FISH) analysis revealed that associated microbial abundance significantly increased owing to intermittent aeration. These results indicated intermittent aeration CWs might be an effective and sustainable strategy for wastewater treatment in rural areas, but require further full-scale investigation in future. PMID:27246456

  16. Institutions for Collective Action among Settled Fulani Agro-Pastoralists in Southwest Nigeria

    Science.gov (United States)

    Fabusoro, E.; Sodiya, C. I.

    2011-01-01

    The study identifies institutions for organizing collective action among settled Fulani agro-pastoralists in southwest Nigeria and examines their functions, processes and tools for fostering collective action. Four Fulani communities were selected purposively in Ekiti State; data were collected from 55 settled pastoralists through informal…

  17. HAWAII UNDERGROUND STORAGE TANKS

    Science.gov (United States)

    This is a point coverage of underground storage tanks(UST) for the state of Hawaii. The original database was developed and is maintained by the State of Hawaii, Dept. of Health. The point locations represent facilities where one or more underground storage tanks occur. Each fa...

  18. Biodegradation of beet molasses vinasse by a mixed culture of micro organisms: Effect of aeration conditions and pH control

    Institute of Scientific and Technical Information of China (English)

    Krzysztof Lutoslawski; Agnieszka Ryznar-Luty; Edmund Cibis; Malgorzata Krzywonos; Tadeusz Mi(s)kiewicz

    2011-01-01

    The effect of aeration conditions and pH control on the progress and efficiency of beet molasses vinasse biodegradation was investigated during four batch processes at 38℃ with the mixed microbial culture composed of Bifidobacterium,Lactobacillus,Lactococcus,Streptococcus,Bacillus,Rhodopseudomonas,and Saccharomyces.The four processes were carried out in a shake flask with no pH control,an aerobic bioreactor without mixing with no pH control,and a stirred-tank reactor (STR) with aeration with and without pH control,respectively.All experiments were started with an initial pH 8.0.The highest efficiency of biodegradation was achieved through the processes conducted in the STR,where betaine (an organic pollutant occurring in beet molasses in very large quantities) was completely degraded by the microorganisms.The process with no pH control carried out in the STR produced the highest reduction in the following pollution measures:organic matter expressed as chemical oxygen demand determined by the dichromatic method + theoretical COD of betaine (CODsum,85.5%),total organic carbon (TOC,78.8%) and five-day biological oxygen demand (BOD5,98.6%).The process conditions applied in the shake flask experiments,as well as those used in the aerobic bioreactor without mixing,failed to provide complete betaine assimilation.As a consequence,reduction in CODwum,TOC and BOD5 was approximately half that obtained with STR.

  19. CARBON REMOVAL FROM METALLIC SILICON BY CARBIDE SETTLING FOR SOLAR GRADE SILICON PRODUCTION

    Directory of Open Access Journals (Sweden)

    Tiago Ramos Ribeiro

    2015-03-01

    Full Text Available The use of solar energy is growing sharply in the past years. The most used material for solar cells is high-purity silicon produced by refining low-purity silicon. With the increasing demand for photovoltaic components, new refining processes have been investigated. Carbon is one of the impurities to be removed and one possible removing technique is based on the settling of silicon carbide particles. Settling tests were carried out at 1,500°C during one and six hours. Results show that differences in settling time do not affect carbon removal significantly and that the carbon contents after settling are still higher than that required by standards for solar grade silicon (43 ppm. Results from this work and from literature show that settling is not a feasible processing step for carbon removal to the level needed for photovoltaic applications.

  20. Tank characterization reference guide

    International Nuclear Information System (INIS)

    Characterization of the Hanford Site high-level waste storage tanks supports safety issue resolution; operations and maintenance requirements; and retrieval, pretreatment, vitrification, and disposal technology development. Technical, historical, and programmatic information about the waste tanks is often scattered among many sources, if it is documented at all. This Tank Characterization Reference Guide, therefore, serves as a common location for much of the generic tank information that is otherwise contained in many documents. The report is intended to be an introduction to the issues and history surrounding the generation, storage, and management of the liquid process wastes, and a presentation of the sampling, analysis, and modeling activities that support the current waste characterization. This report should provide a basis upon which those unfamiliar with the Hanford Site tank farms can start their research

  1. 49 CFR 179.201 - Individual specification requirements applicable to non-pressure tank car tanks.

    Science.gov (United States)

    2010-10-01

    ... to non-pressure tank car tanks. 179.201 Section 179.201 Transportation Other Regulations Relating to... MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes... car tanks....

  2. A BIOPHYSIOCHEMICAL ANALYSIS OF SETTLED LIVESTOCK AND POULTRY HOUSING DUSTS

    Directory of Open Access Journals (Sweden)

    Carresse Gerald

    2014-01-01

    Full Text Available The levels and composition of agricultural dusts are influenced by animal species, production strategy, housing type and ventilation efficiency. Agricultural dust within animal houses is complex and consists of feed particles, microbes and their products, dander, fecal matter, gases, metals and other organic and inorganic components. Livestock and poultry production facilities may be categorized as confinement, semi-confinement or pasture-based. Characterization of animal husbandry building dust will provide insight into understanding exposures experienced by animals, workers and farm visitors. The goal was to characterize biophysiochemical features of livestock dusts from swine, small ruminant, equine, poultry and cattle husbandry units. Settled dust samples were collected from livestock and poultry housing units at the University Farm and other livestock farms across the state. Morphological features were determined by electron microscopy and gravimetry. Biochemical evaluation consisted of pH determination and trace metal detection via mass spectrometry. Biological assessment centered on bacterial characterization via selective media, DNA analysis and endotoxin quantitation. Morphological analyses revealed higher levels of respirable and thoracic particles in poultry, swine, small ruminant and equine units compared to the dairy unit (p<0.01. Dusts were slightly acidic with the exception of the NCAT small ruminant unit (p<0.05. Dust endotoxin levels were consistent and bacterial species detected include Listeria and Escherichia coli. These findings suggest animal husbandry buildings harbor higher levels of smaller respirable and thoracic dust particles compared to inhalable particles. This information may be helpful in understanding dust exposures experienced by animals, farmers and agricultural workers.

  3. Removal of radon by aeration: testing of various aeration techniques for small water works. For European Commission under Contract No FI4PCT960054 TENAWA project

    Energy Technology Data Exchange (ETDEWEB)

    Salonen, L.; Mehtonen, J. [Radiation and Nuclear Safety Authority, Helsinki (Finland); Turunen, H. [Vartiainen Oy, Water Engineering Company (Finland); Mjoenes, L.; Hagberg, N. [SSI, Swedish Radiation Protection Institute (Sweden); Raff, O. [ESWE, Institute of Water Research and Water Technology (Germany)

    2002-12-01

    Capability of various aeration techniques to remove radon from water in small waterworks was studied as a part of project (Treatment Techniques for Removing Natural Radionuclides from Drinking Water), which was carried out during 1997-1999 on a cost-shared basis (contract No. F14PCT960054) with The European Commission (CEC) under the supervision of the Directorate-General XII Radiation Protection Research Unit. In TENAWA project both laboratory and field experiments were performed in order to find reliable methods and equipment for removing natural radionuclides from ground water originating either from private wells or small waterworks. Because such techniques are more often needed in private households than at waterworks, the main emphasis of the research was aimed to solve the water treatment problems related to the private water supplies, especially bedrock wells. Radon was the most important radionuclide to be removed from water at waterworks whereas the removal of other radionuclides ({sup 234,238}U, {sup 226,228}Ra, {sup 210}Pb and {sup 210}Po) was oft required from radonrich bedrock waters. The currently available methods and equipment were mainly tested during the field and laboratory experiments but the project was also aimed to find new materials, absorbents and membranes applicable for radionuclide removal from various types of ground waters (e.g. soft, hard, acidic). Because iron, manganese or organic occur in waters with radionuclides, their simultaneous removal was also studied. The project was divided into 13 work packages. In this report the results of the work package 2.2 are described. Elevated levels of radon and other natural radionuclides in European ground waters have been observed mainly in wide areas of the crystalline Scandinavian bedrock, especially in the granite rock areas of Finland and Sweden but also in more limited crystalline rock areas of Central and Southern Europe, Ukraine and Scotland. The radon removal efficiencies of

  4. Removal of radon by aeration: testing of various aeration techniques for small water works. For European Commission under Contract No FI4PCT960054 TENAWA project

    International Nuclear Information System (INIS)

    Capability of various aeration techniques to remove radon from water in small waterworks was studied as a part of project (Treatment Techniques for Removing Natural Radionuclides from Drinking Water), which was carried out during 1997-1999 on a cost-shared basis (contract No. F14PCT960054) with The European Commission (CEC) under the supervision of the Directorate-General XII Radiation Protection Research Unit. In TENAWA project both laboratory and field experiments were performed in order to find reliable methods and equipment for removing natural radionuclides from ground water originating either from private wells or small waterworks. Because such techniques are more often needed in private households than at waterworks, the main emphasis of the research was aimed to solve the water treatment problems related to the private water supplies, especially bedrock wells. Radon was the most important radionuclide to be removed from water at waterworks whereas the removal of other radionuclides (234,238U, 226,228Ra, 210Pb and 210Po) was oft required from radonrich bedrock waters. The currently available methods and equipment were mainly tested during the field and laboratory experiments but the project was also aimed to find new materials, absorbents and membranes applicable for radionuclide removal from various types of ground waters (e.g. soft, hard, acidic). Because iron, manganese or organic occur in waters with radionuclides, their simultaneous removal was also studied. The project was divided into 13 work packages. In this report the results of the work package 2.2 are described. Elevated levels of radon and other natural radionuclides in European ground waters have been observed mainly in wide areas of the crystalline Scandinavian bedrock, especially in the granite rock areas of Finland and Sweden but also in more limited crystalline rock areas of Central and Southern Europe, Ukraine and Scotland. The radon removal efficiencies of different aeration methods

  5. Sludge Batch 7 (SB7) Washing Demonstration To Determine Sulfate/Oxalate Removal Efficiency And Settling Behavior

    International Nuclear Information System (INIS)

    To support Sludge Batch 7 (SB7) washing, a demonstration of the proposed Tank Farm washing operation was performed utilizing a real-waste test slurry generated from Tank 4, 7, and 12 samples. The purpose of the demonstration was twofold: (1) to determine the settling time requirements and washing strategy needed to bring the SB7 slurry to the desired endpoint; and (2) to determine the impact of washing on the chemical and physical characteristics of the sludge, particularly those of sulfur content, oxalate content, and rheology. Seven wash cycles were conducted over a four month period to reduce the supernatant sodium concentration to approximately one molar. The long washing duration was due to the slow settling of the sludge and the limited compaction. Approximately 90% of the sulfur was removed through washing, and the vast majority of the sulfur was determined to be soluble from the start. In contrast, only about half of the oxalate was removed through washing, as most of the oxalate was initially insoluble and did not partition to the liquid phase until the latter washes. The final sulfur concentration was 0.45 wt% of the total solids, and the final oxalate concentration was 9,900 mg/kg slurry. More oxalate could have been removed through additional washing, although the washing would have reduced the supernatant sodium concentration.The yield stress of the final washed sludge (35 Pa) was an order of magnitude higher than that of the unwashed sludge (∼4 Pa) and was deemed potentially problematic. The high yield stress was related to the significant increase in insoluble solids that occurred (∼8 wt% to ∼18 wt%) as soluble solids and water were removed from the slurry. Reduction of the insoluble solids concentration to ∼14 wt% was needed to reduce the yield stress to an acceptable level. However, depending on the manner that the insoluble solids adjustment was performed, the final sodium concentration and extent of oxalate removal would be prone to

  6. SLUDGE BATCH 7 (SB7) WASHING DEMONSTRATION TO DETERMINE SULFATE/OXALATE REMOVAL EFFICIENCY AND SETTLING BEHAVIOR

    Energy Technology Data Exchange (ETDEWEB)

    Reboul, S.; Click, D.; Lambert, D.

    2010-12-10

    To support Sludge Batch 7 (SB7) washing, a demonstration of the proposed Tank Farm washing operation was performed utilizing a real-waste test slurry generated from Tank 4, 7, and 12 samples. The purpose of the demonstration was twofold: (1) to determine the settling time requirements and washing strategy needed to bring the SB7 slurry to the desired endpoint; and (2) to determine the impact of washing on the chemical and physical characteristics of the sludge, particularly those of sulfur content, oxalate content, and rheology. Seven wash cycles were conducted over a four month period to reduce the supernatant sodium concentration to approximately one molar. The long washing duration was due to the slow settling of the sludge and the limited compaction. Approximately 90% of the sulfur was removed through washing, and the vast majority of the sulfur was determined to be soluble from the start. In contrast, only about half of the oxalate was removed through washing, as most of the oxalate was initially insoluble and did not partition to the liquid phase until the latter washes. The final sulfur concentration was 0.45 wt% of the total solids, and the final oxalate concentration was 9,900 mg/kg slurry. More oxalate could have been removed through additional washing, although the washing would have reduced the supernatant sodium concentration.The yield stress of the final washed sludge (35 Pa) was an order of magnitude higher than that of the unwashed sludge ({approx}4 Pa) and was deemed potentially problematic. The high yield stress was related to the significant increase in insoluble solids that occurred ({approx}8 wt% to {approx}18 wt%) as soluble solids and water were removed from the slurry. Reduction of the insoluble solids concentration to {approx}14 wt% was needed to reduce the yield stress to an acceptable level. However, depending on the manner that the insoluble solids adjustment was performed, the final sodium concentration and extent of oxalate removal

  7. Modeling and analysis of ORNL horizontal storage tank mobilization and mixing

    International Nuclear Information System (INIS)

    The retrieval and treatment of radioactive sludges that are stored in tanks constitute a prevalent problem at several US Department of Energy sites. The tanks typically contain a settled sludge layer with non-Newtonian rheological characteristics covered by a layer of supernatant. The first step in retrieval is the mobilization and mixing of the supernatant and sludge in the storage tanks. Submerged jets have been proposed to achieve sludge mobilization in tanks, including the 189 m3 (50,000 gallon) Melton Valley Storage tanks (MVST) at Oak Ridge National Laboratory (ORNL) and the planned 378 m3 (100,000 gallon) tanks being designed as part of the MVST Capacity Increase Project (MVST-CIP). This report focuses on the modeling of mixing and mobilization in horizontal cylindrical tanks like those of the MVST design using submerged, recirculating liquid jets. The computer modeling of the mobilization and mixing processes uses the TEMPEST computational fluid dynamics program (Trend and Eyler 1992). The goals of the simulations are to determine under what conditions sludge mobilization using submerged liquid jets is feasible in tanks of this configuration, and to estimate mixing times required to approach homogeneity of the contents

  8. Research on factors influencing radon exhalation rate on aerated concrete block

    International Nuclear Information System (INIS)

    The research was carried out on the variation of the radon exhalation rate of aerated concrete block with the water content and dimension by using the RAD7 radon monitor and the radon exhalation rate test cabin of building materials. The result indicates that the amount of the same samples has no influence on the samples' radon exhalation; if the volume of the aerated concrete block in the test cabin is unchanged and the surface area increases, the radon exhalation rate decreases, but the total of the radon exhaling from the surface of the aerated concrete block keeps constant; for the aerated concrete block, its radon exhalation rate increases with water content as logarithmic growth. (authors)

  9. Effects of impeller speed and aeration rate on flotation performance of sulphide ore

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of aeration rate and impeller speed on the concentrate sulfur grade and recovery for batch flotation of a complex sulphide ore were investigated. The relationships between the water recovery and solid entrainment were discussed. It is found that the solid entrainment is linearly related to the water recovery regardless of aeration rate and impeller speed, and the higher sulfur recovery at the aeration rate of 2 and 4 L/min for the impeller speed of 1 500 r/min is considered to be the contribution of true flotation. Finally, the sulfur recovery flux is correlated with the bubble surface area flux based on the froth image at the different aeration rates and impeller speeds.

  10. Improving microalgal growth with small bubbles in a raceway pond with swing gas aerators.

    Science.gov (United States)

    Yang, Zongbo; Cheng, Jun; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2016-09-01

    A novel swing gas aerator was developed to generate small bubbles for improving the mass transfer coefficient and microalgal growth rate in a raceway pond. A high-speed photography system (HSP) was used to measure the bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure the mass transfer coefficient and mixing time. Bubble generation time and diameter decreased by 21% and 9%, respectively, when rubber gas aerators were swung in the microalgae solution. When water pump power and gas aeration rate increased in a raceway pond with swing gas aerators and oscillating baffles (SGAOB), bubble generation time and diameter decreased but solution velocity and mass transfer coefficient increased. The mass transfer coefficient increased by 25% and the solution velocity increased by 11% when SGAOB was used, and the microalgal biomass yield increased by 18%. PMID:27243604

  11. SONIC SPEED AND SHOCK WAVE IN HIGH VELOCITY AERATED FLOWS FROM HIGH HEAD DISCHARGE STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    Dong Zhi-yong

    2003-01-01

    The compressible characteristics in aerated flows at the high velocity of about 50m/s were analyzed. Based on the theory of compressible the relations between the sonic speed and shock wave in high-velocity aerated flow were theoretically deduced. And comparisons with measured data were made. The theoretical and experimental results show the sonic speed in aerated flow is merely of the order of several-dozen meters per second, and its minimum value is only 20m/s, which is far much less than that in water or air alone. So high subsonic flow, supersonic flow and transonic flow as well as compression wave, shock wave and expansion wave similarly to aerodnamics may be produced in high velocity aerated flow at the speed of the order of 50m/s. Hence the influences of these compressible characteristics on high head discharge structures can not be neglected, especially on super high dams over 200m high.

  12. Effects of Aerated Irrigation on Leaf Senescence at Late Growth Stage and Grain Yield of Rice

    Institute of Scientific and Technical Information of China (English)

    ZHU Lian-feng; Yu Sheng-miao; JIN Qian-yu

    2012-01-01

    With the japonica inbred cultivar Xiushui 09,indica hybrid combinations Guodao 6 and Liangyoupeijiu as materials,field experiments were conducted in 2007 and 2008 to study the effects of aerated irrigation on leaf senescence at late growth stage and grain yield of rice.The dissolved oxygen concentration of aerated water evidently increased and decreased at a slow rate.The soil oxidation-reduction potential under aerated irrigation treatment was significantly higher than that of the CK,contributing to significant increases in effective panicles,seed setting rate and grain yield.In addition,the aerated irrigation improved root function,increased superoxide dismutase activity and decreased malondialdehyde content in flag leaves at post-flowering,which delayed leaf senescence process,prolonged leaf functional activity and led to enhanced grain filling.

  13. Fluctuant characteristics of two-phase flow behind a bottom aerator

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  14. Integral Parameters for Characterizing Water, Energy, and Aeration Properties of Soilless Plant Growth Media

    DEFF Research Database (Denmark)

    Chamindu, Deepagoda; Lopez, Jose Choc Chen; Møldrup, Per;

    2013-01-01

    systems are regaining increased worldwide attention. The optimal control of water availability and aeration is an essential prerequisite to successfully operate plant growth systems with soilless substrates such as aggregated foamed glass, perlite, rockwool, coconut coir, or mixtures thereof. While...

  15. Tank 241-C-101 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, WHC 222-S Laboratory, and PNL 325 Analytical Chemistry Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples from tank 241-C-101

  16. Tank 241-C-101 tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, R.D.

    1994-12-06

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, WHC 222-S Laboratory, and PNL 325 Analytical Chemistry Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples from tank 241-C-101.

  17. Tank 241-AX-102 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, WHC 222-S Laboratory, and PNL 325 Analytical Chemistry Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples from tank 241-AX-102

  18. Tank 241-BY-105 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, PNL 325 Analytical Chemistry Laboratory, and WHC 222-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-BY-105

  19. Tank 241-BX-103 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 222-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-BX-103

  20. Tank 241-C-102 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, WHC 222-S Laboratory, and PNL 325 Analytical Chemistry Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples from tank 241-C-102

  1. Tank 241-AP-107 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, WHC 222-S Laboratory, and PNL 325 Analytical Chemistry Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples from tank 241-AP-107

  2. Tank 241-TY-104 Tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, R.D. [Westinghouse Hanford Co., Richland, WA (United States)

    1995-02-15

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 222-C Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-TY-104.

  3. Tank 241-TY-106 Tank Characterization Plan

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, R.D.

    1995-02-22

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 222-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-TY-106.

  4. Tank 241-BX-103 tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Bell, K.E. [Westinghouse Hanford Co., Richland, WA (United States)

    1995-04-21

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 222-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-BX-103.

  5. Tank 241-C-203: Tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, R.D.

    1995-03-06

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 222-S Laboratory. Scope of this plan is to provide guidance for sampling and analysis of samples for tank 241-C-203.

  6. Tank 241-U-201 tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, R.D.

    1995-02-21

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 22-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-U-201.

  7. Tank 241-SX-115 tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, L.M.

    1995-04-24

    This document is a plan which serves as the contractual agreement between the Characterization Project, Sampling Operations, and WHC 222-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-SX-115.

  8. Tank 241-C-202: Tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, R.D.

    1995-03-06

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 222-S Laboratory. Scope of this plan is to provide guidance for sampling and analysis of samples for tank 241-C-202.

  9. Tank 241-U-202 tank characterization plan

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, R.D.

    1995-02-21

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 222-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-U-202.

  10. Tank 241-BY-106 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, PNL 325 Analytical Chemistry Laboratory, and WHC 222-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-BY-106

  11. Tank 241-SX-115 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Project, Sampling Operations, and WHC 222-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-SX-115

  12. Tank 241-BY-103 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, WHC 222-S Laboratory, Oak Ridge National Laboratory, and PNL 329 Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-BY-103

  13. Tank 241-C-105 tank characterization plan

    International Nuclear Information System (INIS)

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, WHC 222-S Laboratory, and PNL 325 Analytical Chemistry Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples from tank 241-C-105

  14. THE ROLE OF DUCKWEED (LEMNA MINOR L. IN SECONDARY CLARIFIER TANKS

    Directory of Open Access Journals (Sweden)

    Engin Gürtekin

    2008-01-01

    Full Text Available In this study, the effects of duckweed (Lemna minor L. presence on the effluent water quality and settling characteristics in the secondary clarifier tank of a conventional biological treatment plant were investigated. For this purpose, the performances of the secondary clarifier with and without duckweed were compared. In the secondary clarifier tank with duckweed, COD, BOD5, ammonium and phosphate removal efficiencies were higher by 15, 25, 35 and 45%, respectively. SS concentration of effluent and values of sludge volume index (SVI were the same. The results showed that duckweed contributes to treatment efficiency of conventional biological treatment plant, which reduces the need of tertiary nutrients removal.

  15. Comparative Analysis of ANN based Intelligent Controllers for Three Tank System

    Directory of Open Access Journals (Sweden)

    Kodali Vijaya Lakshmi

    2016-03-01

    Full Text Available Three tank liquid level control system plays a significant role in process industries and its behavior is nonlinear in nature. Conventional PID controller generally does not work effectively for such systems. This paper deals with the design of three intelligent controllers namely model predictive, model reference and NARMA-L2 controllers based on artificial neural net-works for a three tank level process. These controllers are simulated using MATLAB/SIMULINK. The performance indices of intelligent controllers are compared based on the time domain specifications. The performance of NN predictive controller shows superiority over other controllers in terms of settling time.

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

    OpenAIRE

    U.O. Enwereuzoh; G.N. Onyeagoro

    2014-01-01

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

  17. Subsurface aeration of anaerobic groundwater : iron colloid formation and the nitrification process

    OpenAIRE

    Wolthoorn, A.

    2003-01-01

    Keywords: Iron, anaerobic groundwater, groundwater purification, heterogeneous oxidation, iron colloid formation, electron microscopy, nitrification In anaerobic groundwater iron and ammonium can be found in relatively high concentrations. These substances need to be removed when groundwater is used for the production of drinking water. Subsurface aeration can be applied to remove iron before the groundwater reaches the purification plant. The primary goal of subsurface aeration is to oxidise...

  18. Expired CO2 Levels Indicate Degree of Lung Aeration at Birth

    OpenAIRE

    Hooper, Stuart B.; Fouras, Andreas; Siew, Melissa; Wallace, Megan; Kitchen, Marcus; te Pas, Arjan B; Klingenberg, Claus; Lewis, Robert; Davis, Peter; Morley, Colin J; Schmölzer, Georg M.

    2013-01-01

    As neonatal resuscitation critically depends upon lung aeration at birth, knowledge of the progression of this process is required to guide ongoing care. We investigated whether expired CO2 (ECO2) levels indicate the degree of lung aeration immediately after birth in two animal models and in preterm infants. Lambs were delivered by caesarean section and ventilated from birth. In lambs, ECO2 levels were significantly (p

  19. Microstructure–texture relationships of aerated sugar gels: Novel measurement techniques for analysis and control

    OpenAIRE

    Herremans, Els; Bongaers, Evi; Estrade, Pascal; Gondek, Ewa; Hertog, Maarten; Jakubczyk, Ewa; Nguyen Do Trong, Nghia; Rizzolo, Anna; Saeys, Wouter; Spinelli, Lorenzo; Torricelli, Alessandro; Vanoli, Maristella; Verboven, Pieter; Nicolaï, Bart

    2013-01-01

    Proper control of the texture properties of aerated foods demands accurate measurement tools. Aerated sugar gels with identical composition but different microstructures were produced by applying different mixing times of 2, 4 and 8 minutes. Compression test and acoustic emission measurements were carried out to characterize the mechanical properties of these foams. Significant differences in deformation properties and number of acoustic events were found depending on the foaming time, indic...

  20. Tow Tank #1

    Science.gov (United States)

    1930-01-01

    Digging the channel for the Tow Tank. In the late 1920s, the NACA decided to investigate the aero/hydro dynamics of floats for seaplanes. A Hydrodynamics Branch was established in 1929 and special towing basin was authorized in March of that same year. Starr Truscott (the first head of the new division) described the tank in NACA TR 470: 'The N.A.C.A. tank is of the Froude type; that is, the model which is being tested is towed through still water at successive constant speeds from a carriage spanning the tank. At each constant speed the towing pull is measured, the trim and the rise, or change of draft, are recorded and, if the model is being towed at a fixed trim, the moment required to hold it there is measured and recorded.' 'The reinforced concrete basin containing the water has the following dimensions: (1) Length on water, extreme, 2,020 feet; (2) Normal width of water surface, 24 feet; (3) Normal depth of water, 12 feet; (4) Length of 12 foot depth, 1,980 feet.' The tank was dedicated on May 27, 1931. In 1936 the tank was extended to a total length of 2,960 feet. In 1959 the facility was turned over to the U.S. Navy.Published in NACA TR No. 470, 'The N.A.C.A. Tank: A High-Speed Towing Basin for Testing Models of Seaplane Floats,' by Starr Truscott, 1933.

  1. TANK FARM ENVIRONMENTAL REQUIREMENTS

    International Nuclear Information System (INIS)

    Through regulations, permitting or binding negotiations, Regulators establish requirements, limits, permit conditions and Notice of Construction (NOC) conditions with which the Office of River Protection (ORP) and the Tank Farm Contractor (TFC) must comply. Operating Specifications are technical limits which are set on a process to prevent injury to personnel, or damage to the facility or environment, The main purpose of this document is to provide specification limits and recovery actions for the TFC Environmental Surveillance Program at the Hanford Site. Specification limits are given for monitoring frequencies and permissible variation of readings from an established baseline or previous reading. The requirements in this document are driven by environmental considerations and data analysis issues, rather than facility design or personnel safety issues. This document is applicable to all single-shell tank (SST) and double-shell tank (DST) waste tanks, and the associated catch tanks and receiver tanks, and transfer systems. This Tank Farm Environmental Specifications Document (ESD) implements environmental-regulatory limits on the configuration and operation of the Hanford Tank Farms facility that have been established by Regulators. This ESD contains specific field operational limits and recovery actions for compliance with airborne effluent regulations and agreements, liquid effluents regulations and agreements, and environmental tank system requirements. The scope of this ESD is limited to conditions that have direct impact on Operations/Projects or that Operations Projects have direct impact upon. This document does not supercede or replace any Department of Energy (DOE) Orders, regulatory permits, notices of construction, or Regulatory agency agreements binding on the ORP or the TFC. Refer to the appropriate regulation, permit, or Notice of Construction for an inclusive listing of requirements

  2. NACA Tow Tank

    Science.gov (United States)

    1930-01-01

    L4695 shows the interior view of construction of the Tow Tank. In the late 1920s, the NACA decided to investigate the aero/hydro dynamics of floats for seaplanes. A Hydrodynamics Branch was established in 1929 and special towing basin was authorized in March of that same year. Starr Truscott (the first head of the new division) described the tank in NACA TR 470: 'The N.A.C.A. tank is of the Froude type; that is, the model which is being tested is towed through still water at successive constant speeds from a carriage spanning the tank. At each constant speed the towing pull is measured, the trim and the rise, or change of draft, are recorded and, if the model is being towed at a fixed trim, the moment required to hold it there is measured and recorded.' 'The reinforced concrete basin containing the water has the following dimensions: (1) Length on water, extreme, 2,020 feet; (2) Normal width of water surface, 24 feet; (3) Normal depth of water, 12 feet; (4) Length of 12 foot depth, 1,980 feet.' This picture shows the tank before the coving was added. This brought the rails for the carriage closer together and helped suppress waves produced by the models. The finished tank would be filled with approximately 4 million gallons of salt water pumped in from the Back River. The tank was covered by a shelter which protected the water surface. The tank was dedicated on May 27, 1931. In 1936 the tank was extended to a total length of 2,960 feet. In 1959 the facility was turned over to the U.S. Navy.

  3. Parametric Analyses of Heat Removal from High-Level Waste Tanks

    International Nuclear Information System (INIS)

    The general thermal hydraulics program GOTH-SNF was used to predict the thermal response of the waste in tanks 241-AY-102 and 241-AZ-102 when mixed by two 300 horsepower mixer pumps. This mixing was defined in terms of a specific waste retrieval scenario. Both dome and annulus ventilation system flow are necessary to maintain the waste within temperature control limits during the mixing operation and later during the sludge-settling portion of the scenario are defined

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

    Science.gov (United States)

    Albaek, Mads O; Gernaey, Krist V; Hansen, Morten S; Stocks, Stuart M

    2011-08-01

    The purpose of this article is to demonstrate how a model can be constructed such that the progress of a submerged fed-batch fermentation of a filamentous fungus can be predicted with acceptable accuracy. The studied process was enzyme production with Aspergillus oryzae in 550 L pilot plant stirred tank reactors. Different conditions of agitation and aeration were employed as well as two different impeller geometries. The limiting factor for the productivity was oxygen supply to the fermentation broth, and the carbon substrate feed flow rate was controlled by the dissolved oxygen tension. In order to predict the available oxygen transfer in the system, the stoichiometry of the reaction equation including maintenance substrate consumption was first determined. Mainly based on the biomass concentration a viscosity prediction model was constructed, because rising viscosity of the fermentation broth due to hyphal growth of the fungus leads to significant lower mass transfer towards the end of the fermentation process. Each compartment of the model was shown to predict the experimental results well. The overall model can be used to predict key process parameters at varying fermentation conditions. PMID:21370231

  5. Ecophysiology of wetland plant roots: A modelling comparison of aeration in relation to species distribution

    Science.gov (United States)

    Sorrell, B.K.; Mendelssohn, I.A.; McKee, K.L.; Woods, R.A.

    2000-01-01

    This study examined the potential for inter-specific differences in root aeration to determine wetland plant distribution in nature. We compared aeration in species that differ in the type of sediment and depth of water they colonize. Differences in root anatomy, structure and physiology were applied to aeration models that predicted the maximum possible aerobic lengths and development of anoxic zones in primary adventitious roots. Differences in anatomy and metabolism that provided higher axial fluxes of oxygen allowed deeper root growth in species that favour more reducing sediments and deeper water. Modelling identified factors that affected growth in anoxic soils through their effects on aeration. These included lateral root formation, which occurred at the expense of extension of the primary root because of the additional respiratory demand they imposed, reducing oxygen fluxes to the tip and stele, and the development of stelar anoxia. However, changes in sediment oxygen demand had little detectable effect on aeration in the primary roots due to their low wall permeability and high surface impedance, but appeared to reduce internal oxygen availability by accelerating loss from laterals. The development of pressurized convective gas flow in shoots and rhizomes was also found to be important in assisting root aeration, as it maintained higher basal oxygen concentrations at the rhizome-root junctions in species growing into deep water. (C) 2000 Annals of Botany Company.

  6. Aeration effect on Spirulina platensis growth and γ-linolenic acid production

    Directory of Open Access Journals (Sweden)

    Srinivasa Reddy Ronda

    2012-03-01

    Full Text Available The influence of aeration on algal growth and gamma-linolenic acid (GLA production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2-2.5 vvm. Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g-1 dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vvm enhanced both the specific growth rate and GLA content under periodic sparging in the bicarbonate medium. With a 6-fold increase in the aeration rate, the GLA content of the alga increased by 69.64% (5.6-9.5 mg· g-1 dry cell weight. In addition, the total fatty acid (TFA content in dry biomass increased from 2.22% to 4.41%, whereas the algae maintained a constant GLA to TFA ratio within the aeration rate tested. The dependence of GLA production on the aeration rate was explained by interrelating the GLA production rate with the specific growth rate using the Luedeking and Piret mixed growth model.

  7. Aeration effect on Spirulina platensis growth and γ-Linolenic acid production.

    Science.gov (United States)

    Ronda, Srinivasa Reddy; Bokka, Chandra Sekhar; Ketineni, Chandrika; Rijal, Binod; Allu, Prasada Rao

    2012-01-01

    The influence of aeration on algal growth and gamma-linolenic acid (GLA) production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2- 2.5 vvm). Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g(-1) dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vvm enhanced both the specific growth rate and GLA content under periodic sparging in the bicarbonate medium. With a 6-fold increase in the aeration rate, the GLA content of the alga increased by 69.64% (5.6-9.5 mg· g(-1) dry cell weight). In addition, the total fatty acid (TFA) content in dry biomass increased from 2.22% to 4.41%, whereas the algae maintained a constant GLA to TFA ratio within the aeration rate tested. The dependence of GLA production on the aeration rate was explained by interrelating the GLA production rate with the specific growth rate using the Luedeking and Piret mixed growth model. PMID:24031799

  8. Improving arachidonic acid fermentation by Mortierella alpina through multistage temperature and aeration rate control in bioreactor.

    Science.gov (United States)

    Gao, Min-Jie; Wang, Cheng; Zheng, Zhi-Yong; Zhu, Li; Zhan, Xiao-Bei; Lin, Chi-Chung

    2016-05-18

    Effective production of arachidonic acid (ARA) using Mortierella alpina was conducted in a 30-L airlift bioreactor. Varying the aeration rate and temperature significantly influenced cell morphology, cell growth, and ARA production, while the optimal aeration rate and temperature for cell growth and product formation were quite different. As a result, a two-stage aeration rate control strategy was constructed based on monitoring of cell morphology and ARA production under various aeration rate control levels (0.6-1.8 vvm). Using this strategy, ARA yield reached 4.7 g/L, an increase of 38.2% compared with the control (constant aeration rate control at 1.0 vvm). Dynamic temperature-control strategy was implemented based on the fermentation performance at various temperatures (13-28°C), with ARA level in total cellular lipid increased by 37.1% comparing to a constant-temperature control (25°C). On that basis, the combinatorial fermentation strategy of two-stage aeration rate control and dynamic temperature control was applied and ARA production achieved the highest level of 5.8 g/L. PMID:26038800

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

    Science.gov (United States)

    Raga, Roberto; Cossu, Raffaello

    2013-04-01

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

  10. Development of smart solar tanks

    DEFF Research Database (Denmark)

    Furbo, Simon; Andersen, Elsa

    1999-01-01

    The aim of the project is to develop smart solar tanks. A smart solar tank is a tank in which the domestic water can bee heated both by solar collectors and by an auxiliary energy supply system. The auxiliary energy supply system heats up the hot-water tank from the top and the water volume heated...

  11. A two-fluid model for violent aerated flows

    CERN Document Server

    Dias, Frédéric; Ghidaglia, Jean-Michel

    2008-01-01

    In the study of ocean wave impact on structures, one often uses Froude scaling since the dominant force is gravity. However the presence of trapped or entrained air in the water can significantly modify wave impacts. When air is entrained in water in the form of small bubbles, the acoustic properties in the water change dramatically. While some work has been done to study small-amplitude disturbances in such mixtures, little work has been done on large disturbances in air-water mixtures. We propose a basic two-fluid model in which both fluids share the same velocities and analyze some of its properties. It is shown that this model can successfully mimic water wave impacts on coastal structures. The governing equations are discretized by a second-order finite volume method. Numerical results are presented for two examples: the dam break problem and the drop test problem. It is shown that this basic model can be used to study violent aerated flows, especially by providing fast qualitative estimates.

  12. Fate of Pathogen Indicators During Extended Aeration Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Norshuhaila Mohamed Sunar

    2015-05-01

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

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

    International Nuclear Information System (INIS)

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

  14. Fine-pore aeration diffusers: accelerated membrane ageing studies.

    Science.gov (United States)

    Kaliman, An; Rosso, Diego; Leu, Shao-Yuan; Stenstrom, Michael K

    2008-01-01

    Polymeric membranes are widely used in aeration systems for biological treatment. These membranes may degrade over time and are sensitive to fouling and scaling. Membrane degradation is reflected in a decline in operating performance and higher headloss, resulting in increased energy costs. Mechanical property parameters, such as membrane hardness, Young's modulus, and orifice creep, were used to characterize the performance of membranes over time in operation and to predict their failure. Used diffusers from municipal wastewater treatment plants were collected and tested for efficiency and headloss, and then dissected to facilitate measurements of Young's modulus, hardness, and orifice creep. Higher degree of membrane fouling corresponded consistently with larger orifice creep. A lab-scale membrane ageing simulation was performed with polyurethane and four different ethylene-propylene-diene (EPDM) membrane diffusers by subjecting them to chemical ageing cycles and periodic testing. The results confirmed full-scale plant results and showed the superiority of orifice creep over Young's modulus and hardness in predicting diffuser deterioration. PMID:17706264

  15. Atrazine removal from aqueous solutions using submerged biological aerated filter.

    Science.gov (United States)

    Baghapour, Mohammad Ali; Nasseri, Simin; Derakhshan, Zahra

    2013-01-01

    Atrazine is widely used in the agriculture as an herbicide. Due to its high mobility, Atrazine leaks into the groundwaters, surface waters, and drinking water wells. Many physical and chemical methods have been suggested for removing Atrazine from aquatic environments. However, these methods are very costly, have many performance problems, produce a lot of toxic intermediates which are very harmful and dangerous, and cannot completely mineralize Atrazine. In this study, biodegradation of Atrazine by microbial consortium was evaluated in the aquatic environment. In order to assess the Atrazine removal from the aquatic environment, submerged biological aerated filter (SBAF) was fed with synthetic wastewater based on sucrose and Atrazine at different hydraulic retention times (HRTs). The maximum efficiencies for Atrazine and Soluble Chemical Oxygen Demand (SCOD) removal were 97.9% and 98.9%, respectively. The study findings showed that Stover-Kincannon model had very good fitness (R2 > 99%) in loading Atrazine in the biofilter and by increasing the initial concentration of Atrazine, the removal efficiency increased. Aerobic mixed biofilm culture was observed to be suitable for the treatment of Atrazine from aquatic environment. There was no significant inhibition effect on mixed aerobic microbial consortia. Atrazine degradation depended on the strength of wastewater and the amount of Atrazine in the influent. PMID:24499572

  16. Atrazine Removal from Aqueous Solutions using Submerged Biological Aerated Filter

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Baghapour

    2013-06-01

    Full Text Available Atrazine is widely used in the agriculture as an herbicide. Due to its high mobility, Atrazine leaks into the groundwaters, surface waters, and drinking water wells. Many physical and chemical methods have been suggested for removing Atrazine from aquatic environments. However, these methods are very costly, have many performance problems, produce a lot of toxic intermediates which are very harmful and dangerous, and cannot completely mineralize Atrazine. In this study, biodegradation of Atrazine by microbial consortium was evaluated in the aquatic environment. In order to assess the Atrazine removal from the aquatic environment, submerged biological aerated filter (SBAF was fed with synthetic wastewater based on sucrose and Atrazine at different hydraulic retention times (HRTs. The maximum efficiencies for Atrazine and Soluble Chemical Oxygen Demand (SCOD removal were 97.9% and 98.9%, respectively. The study findings showed that Stover-Kincannon model had very good fitness (R2 > 99% in loading Atrazine in the biofilter and by increasing the initial concentration of Atrazine, the removal efficiency increased. Aerobic mixed biofilm culture was observed to be suitable for the treatment of Atrazine from aquatic environment. There was no significant inhibition effect on mixed aerobic microbial consortia. Atrazine degradation depended on the strength of wastewater and the amount of Atrazine in the influent

  17. Studies on soil aeration with irrigation and response of crops

    International Nuclear Information System (INIS)

    The root zone of the plant must be well supplied with both water and oxygen. Water potential should be kept close to saturation but if a low water tension is maintained, particularly in clay soil, plants will suffer most of the time from a suboptimal level of oxygen supply in the root zone. The diffusion rate of gases in the air is about 10,000 times greater than in water. Thus, it is obvious that the rate of gas diffusion decreases as the water content of the soil increases. These two requirements are apparently contradictory and the assessment of optimum level of soil aeration in the root environment is essential for better crop establishment and growth. Influence of irrigation treatments (three depths of irrigation of 2, 4 and 6 cm and four IW/CPE ratios of 0.45, 0.60, 0.75 and 0.90) on the soil oxygen diffusion rate (ODR) during various growing phases of peanut crop (Arachis hypogaea L.) were studied on a lateritic sandy loam soil (ultisols) for two consecutive seasons. The rate of ODR decreases as water content of the soil increases after irrigation and then increases gradually with the lapse of time. However, it starts decreasing with decrease in soil moisture after 96 hours of irrigation. (author)

  18. Natural radioactivity status in mining settling ponds: Bioaccumulation of Radium in biota and the derived dose

    International Nuclear Information System (INIS)

    A radiological survey has been carried out in two mining settling ponds in Upper Silesia in Poland based on natural radionuclide inventory in abiotic environment and the consequent dose rate assessment for representative species of biota. The distribution of natural radionuclides in the two mining settling ponds was studied in relation to the abiotic environment and the biotic environment interaction. More specific, the study was focused at the abandoned settling ponds of Rontok and Bojszowy, characterized by the presence of high salinity levels and enhanced Radium concentrations, in comparison with the wide Polish territory

  19. Method for measuring settling phenomena by means of frequency domain instrumentation

    Science.gov (United States)

    D'Apuzzo, M.; D'Arco, M.; Liccardo, A.; Vadursi, M.

    2016-05-01

    The paper deals with the analysis of settling phenomena that characterize the step response of digital to analog converters, amplifiers, and several other devices. Settling is described by means of a minimal second order model that is suitable to account for the distortion terms recognized in the signal spectrum. An alternative method for dynamic performance assessment of systems characterized by poor settling performance is then proposed. Thanks to the use of high bandwidth spectrum analyzers, the proposed method overtakes the limits characterizing the measurement approaches based on the use of time-domain instruments in the presence of modern ultra-wideband systems.

  20. System Description for Tank 241-AZ-101 Waste Retrieval Data Acquisition System

    Energy Technology Data Exchange (ETDEWEB)

    ROMERO, S.G.

    2000-02-14

    The proposed activity provides the description of the Data Acquisition System for Tank 241-AZ-101. This description is documented in HNF-5572, Tank 241-AZ-101 Waste Retrieval Data Acquisition System (DAS). This activity supports the planned mixer pump tests for Tank 241-AZ-101. Tank 241-AZ-101 has been selected for the first full-scale demonstration of a mixer pump system. The tank currently holds over 960,000 gallons of neutralized current acid waste, including approximately 12.7 inches of settling solids (sludge) at the bottom of the tank. As described in Addendum 4 of the FSAR (LMHC 2000a), two 300 HP mixer pumps with associated measurement and monitoring equipment have been installed in Tank 241-AZ-101. The purpose of the Tank 241-AZ-101 retrieval system Data Acquisition System (DAS) is to provide monitoring and data acquisition of key parameters in order to confirm the effectiveness of the mixer pumps utilized for suspending solids in the tank. The suspension of solids in Tank 241-AZ-101 is necessary for pretreatment of the neutralized current acid waste and eventual disposal as glass via the Hanford Waste Vitrification Plant. HNF-5572 provides a basic description of the Tank 241-AZ-101 retrieval system DAS, including the field instrumentation and application software. The DAS is provided to fulfill requirements for data collection and monitoring. This document is not an operations procedure or is it intended to describe the mixing operation. This USQ screening provides evaluation of HNF-5572 (Revision 1) including the changes as documented on ECN 654001. The changes include (1) add information on historical trending and data backup, (2) modify DAS I/O list in Appendix E to reflect actual conditions in the field, and (3) delete IP address in Appendix F per Lockheed Martin Services, Inc. request.

  1. Tank 48 - Chemical Destruction

    Energy Technology Data Exchange (ETDEWEB)

    Simner, Steven P.; Aponte, Celia I.; Brass, Earl A.

    2013-01-09

    Small tank copper-catalyzed peroxide oxidation (CCPO) is a potentially viable technology to facilitate the destruction of tetraphenylborate (TPB) organic solids contained within the Tank 48H waste at the Savannah River Site (SRS). A maturation strategy was created that identified a number of near-term development activities required to determine the viability of the CCPO process, and subsequent disposition of the CCPO effluent. Critical activities included laboratory-scale validation of the process and identification of forward transfer paths for the CCPO effluent. The technical documentation and the successful application of the CCPO process on simulated Tank 48 waste confirm that the CCPO process is a viable process for the disposition of the Tank 48 contents.

  2. Tank waste treatment science

    International Nuclear Information System (INIS)

    Remediation efforts at the U.S. Department of Energy's Hanford Site require that many technical and scientific principles be combined for effectively managing and disposing the variety of wastes currently stored in underground tanks. Based on these principles, pretreatment technologies are being studied and developed to separate waste components and enable the most suitable treatment methods to be selected for final disposal of these wastes. The Tank Waste Treatment Science Task at Pacific Northwest Laboratory is addressing pretreatment technology development by investigating several aspects related to understanding and processing the tank contents. The experimental work includes evaluating the chemical and physical properties of the alkaline wastes, modeling sludge dissolution, and evaluating and designing ion exchange materials. This paper gives some examples of results of this work and shows how these results fit into the overall Hanford waste remediation activities. This work is part of series of projects being conducted for the Tank Waste Remediation System

  3. Experimental characterization of jet static forces impacting waste tank components

    Energy Technology Data Exchange (ETDEWEB)

    Bamberger, J.A.; Bates, J.M. (Pacific Northwest Lab., Richland, WA (USA)); Waters, E.D. (Westinghouse Hanford Co., Richland, WA (USA))

    1990-06-01

    Westinghouse Hanford Company plans to install mixer pumps in doubleshell waste tanks to mobilize and suspend settled sludge to allow eventual retrieval for treatment and permanent storage. The mixer pumps produce high momentum, horizontally directed jets that impact and mobilize the sludge and mix it into slurry for removal. There is concern that the force of the jet may damage tank internal components in its path. Scaled experiments were conducted to characterize the velocity profiles of the floor jet and to quantify the drag coefficients and impact forces for three tank components: radiation dry well, air lift circulator, and steam coil. Jet impact forces were measured on the scaled models at a 4 to 1 range of hydraulically scaled flow rates and a scaled range of distances between discharge nozzle and test component. The test were designed to provide hydraulic similarity between test conditions and expected actual waste tank conditions by using equal Reynolds number the jet maximum velocity impacted the test component. Forces measured on the models were used to calculate expected forces on the full scale components. Correlations of force on the test article versus distance from the nozzle were derived for the radiation dry well and air lift circulator based on the velocity correlation and drag parameter. The force data were also used to derive equivalent drag parameters which accounted for component shape factors including variation of jet impact area on the test article with distance from the nozzle. 8 refs., 44 figs., 42 tabs.

  4. TANK 12 SLUDGE CHARACTERIZATION AND ALUMINUM DISSOLUTION DEMONSTRATION

    International Nuclear Information System (INIS)

    A 3-L sludge slurry sample from Tank 12 was characterized and then processed through an aluminum dissolution demonstration. The dominant constituent of the sludge was found to be aluminum in the form of boehmite. The iron content was minor, about one-tenth that of the aluminum. The salt content of the supernatant was relatively high, with a sodium concentration of ∼7 M. Due to these characteristics, the yield stress and plastic viscosity of the unprocessed slurry were relatively high (19 Pa and 27 cP), and the settling rate of the sludge was relatively low (∼20% settling over a two and a half week period). Prior to performing aluminum dissolution, plutonium and gadolinium were added to the slurry to simulate receipt of plutonium waste from H-Canyon. Aluminum dissolution was performed over a 26 day period at a temperature of 65 C. Approximately 60% of the insoluble aluminum dissolved during the demonstration, with the rate of dissolution slowing significantly by the end of the demonstration period. In contrast, approximately 20% of the plutonium and less than 1% of the gadolinium partitioned to the liquid phase. However, about a third of the liquid phase plutonium became solubilized prior to the dissolution period, when the H-Canyon plutonium/gadolinium simulant was added to the Tank 12 slurry. Quantification of iron dissolution was less clear, but appeared to be on the order of 1% based on the majority of data (a minor portion of the data suggested iron dissolution could be as high as 10%). The yield stress of the post-dissolution slurry (2.5 Pa) was an order of magnitude lower than the initial slurry, due most likely to the reduced insoluble solids content caused by aluminum dissolution. In contrast, the plastic viscosity remained unchanged (27 cP). The settling rate of the post-dissolution slurry was higher than the initial slurry, but still relatively low compared to settling of typical high iron content/low salt content sludges. Approximately 40% of the

  5. Tank 12 Sludge Characterization and Aluminum Dissolution Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Reboul, S.; Hay, M.; Zeigler, K; Stone, M.

    2010-05-05

    A 3-L sludge slurry sample from Tank 12 was characterized and then processed through an aluminum dissolution demonstration. The dominant constituent of the sludge was found to be aluminum in the form of boehmite. The iron content was minor, about one-tenth that of the aluminum. The salt content of the supernatant was relatively high, with a sodium concentration of {approx}7 M. Due to these characteristics, the yield stress and plastic viscosity of the unprocessed slurry were relatively high (19 Pa and 27 cP), and the settling rate of the sludge was relatively low ({approx}20% settling over a two and a half week period). Prior to performing aluminum dissolution, plutonium and gadolinium were added to the slurry to simulate receipt of plutonium waste from H-Canyon. Aluminum dissolution was performed over a 26 day period at a temperature of 65 C. Approximately 60% of the insoluble aluminum dissolved during the demonstration, with the rate of dissolution slowing significantly by the end of the demonstration period. In contrast, approximately 20% of the plutonium and less than 1% of the gadolinium partitioned to the liquid phase. However, about a third of the liquid phase plutonium became solubilized prior to the dissolution period, when the H-Canyon plutonium/gadolinium simulant was added to the Tank 12 slurry. Quantification of iron dissolution was less clear, but appeared to be on the order of 1% based on the majority of data (a minor portion of the data suggested iron dissolution could be as high as 10%). The yield stress of the post-dissolution slurry (2.5 Pa) was an order of magnitude lower than the initial slurry, due most likely to the reduced insoluble solids content caused by aluminum dissolution. In contrast, the plastic viscosity remained unchanged (27 cP). The settling rate of the post-dissolution slurry was higher than the initial slurry, but still relatively low compared to settling of typical high iron content/low salt content sludges. Approximately 40

  6. Testing Of Enhanced Chemical Cleaning Of SRS Actual Waste Tank 5F And Tank 12H Sludges

    International Nuclear Information System (INIS)

    using SRS sludge tank sample material. A Task Technical and Quality Assurance Plan (TTQAP) details the experimental plan as outlined by the Technical Task Request (TTR). The TTR identifies that the data produced by this testing and results included in this report will support the technical baseline with portions having a safety class functional classification. The primary goals for SRNL RWT are as follows: (1) to confirm ECC performance with real tank sludge samples, (2) to determine the impact of ECC on fate of actinides and the other sludge metals, and (3) to determine changes, if any, in solids flow and settling behavior.

  7. TESTING OF ENHANCED CHEMICAL CLEANING OF SRS ACTUAL WASTE TANK 5F AND TANK 12H SLUDGES

    Energy Technology Data Exchange (ETDEWEB)

    Martino, C.; King, W.

    2011-08-22

    using SRS sludge tank sample material. A Task Technical and Quality Assurance Plan (TTQAP) details the experimental plan as outlined by the Technical Task Request (TTR). The TTR identifies that the data produced by this testing and results included in this report will support the technical baseline with portions having a safety class functional classification. The primary goals for SRNL RWT are as follows: (1) to confirm ECC performance with real tank sludge samples, (2) to determine the impact of ECC on fate of actinides and the other sludge metals, and (3) to determine changes, if any, in solids flow and settling behavior.

  8. A feasibility study of developing toroidal tanks for a spinning spacecraft. Part 2: Evaluation of fluid behavior in spinning toroidal tanks

    Science.gov (United States)

    Anderson, J. E.

    1974-01-01

    An experimental program was conducted for the purpose of evaluating propellant behavior characteristics in spinning toroidal tanks. The effects of typical mission requirements, and related phenomena upon propellant slosh and settling, and orientation and stability of the ullage were investigated in a subscale model tank under both one-g and low-g acceleration environments. Specific conditions included were axial acceleration, spin rate, spinrate change, and spacecraft wobble, both singly and in combination. Methanol and water in combination with appropriate spin-rates and accelerations of the scale model system were used to simulate the behavior of fluorine, nitrogen tetroxide, monomethylhydrazine, and hydrazine. The experimental results indicate that no major fluid behavior problems would be encountered with the use of toroidal tanks containing any of the four propellants in a proposed spin-stabilized orbiter spacecraft.

  9. Sorption of lead by settling pond soils after reclamation treatments

    Science.gov (United States)

    Asensio, Verónica; Forján, Rubén; Vega, Flora A.; Andrade, Luisa; Covelo, Emma F.

    2013-04-01

    The reclamation of degraded soils adding waste amendments can add significant concentrations of Pb. Because of this, it is important to know the sorption capacity of Pb by the soils where wastes with high concentrations of this metal are applied. To determine the sorption capacity of Pb by mine soils, before and after reclamation treatments, four different sites were selected at a settling pond mine zone: an untreated one as the control sample (B1), a vegetated one with pines for 21 years (B2v), a vegetated with eucalyptus for 6 years (B3v) and an amended with sewage sludges and paper mill residues for 5 months (B4w). All soils had one horizon except B4w, where twice were sampled (B4Aw and B4Bw). The B4Bw is considered analogous of the control soil. To evaluate the sorption capacity by the soils, sorption isotherms were constructed using single-metal solutions of Pb2+ nitrates (0.03, 0.05, 0.08, 0.1 and 0.5 mmol L-1) containing 0.01 M NaNO3 as background electrolyte (Vega et al., 2009). The overall capacity of the soil to sorb Pb was evaluated as the slope Kr (Vega et al., 2008). The obtained results show that the sorption isotherm of Pb by control soil (B1) and its analogous (B4Bw) are of L-type curve, whereas the sorption isotherms of the treated soils (B2v, B3v and B4Aw) are of H-type curve (Giles et al., 1974). The most of the obtained isotherms do not fit with the models of Langmuir or Freundlich, therefore sorption capacity was evaluated by Kr parameter. According to the obtained Kr parameter, B1 and B4Bw have the lowest Pb sorption capacity (Kr = 0.480 and 0.556, respectively), which increased two times after recently waste amending (B4Aw; Kr = 0.998). The vegetated sites (B2v and B3v) also have higher sorption capacity than B1, but lower than B4Aw (Kr = 0.692 and 0.725, respectively). The highest sorption capacity of Pb by the amended soil is due to its characteristics such as high pH and organic carbon content. This is corroborated by the significantly

  10. Liquid Hydrogen Propellant Tank Sub-Surface Pressurization with Gaseous Helium

    Science.gov (United States)

    Stephens, J. R.; Cartagena, W.

    2015-01-01

    A series of tests were conducted to evaluate the performance of a propellant tank pressurization system with the pressurant diffuser intentionally submerged beneath the surface of the liquid. Propellant tanks and pressurization systems are typically designed with the diffuser positioned to apply pressurant gas directly into the tank ullage space when the liquid propellant is settled. Space vehicles, and potentially propellant depots, may need to conduct tank pressurization operations in micro-gravity environments where the exact location of the liquid relative to the diffuser is not well understood. If the diffuser is positioned to supply pressurant gas directly to the tank ullage space when the propellant is settled, then it may become partially or completely submerged when the liquid becomes unsettled in a microgravity environment. In such case, the pressurization system performance will be adversely affected requiring additional pressurant mass and longer pressurization times. This series of tests compares and evaluates pressurization system performance using the conventional method of supplying pressurant gas directly to the propellant tank ullage, and then supplying pressurant gas beneath the liquid surface. The pressurization tests were conducted on the Engineering Development Unit (EDU) located at Test Stand 300 at NASA Marshall Space Flight Center (MSFC). EDU is a ground based Cryogenic Fluid Management (CFM) test article supported by Glenn Research Center (GRC) and MSFC. A 150 ft3 propellant tank was filled with liquid hydrogen (LH2). The pressurization system used regulated ambient helium (GHe) as a pressurant, a variable position valve to maintain flow rate, and two identical independent pressurant diffusers. The ullage diffuser was located in the forward end of the tank and was completely exposed to the tank ullage. The submerged diffuser was located in the aft end of the tank and was completely submerged when the tank liquid level was 10% or greater

  11. Influence of an oxic settling anoxic system on biomass yield, protozoa and filamentous bacteria.

    Science.gov (United States)

    Rodriguez-Perez, Santiago; Fermoso, Fernando G

    2016-01-01

    An oxic settling anoxic system coupled with an activated sludge process has been studied to reduce sewage sludge production. The reduction of sludge yield, excess sludge production and active biomass yield were 51.7%, 52.9% and 67.1%, respectively, compared with the control system. The oxic reactor of the oxic settling anoxic system, even with a lower active biomass concentration than the oxic reactor of control system, showed a higher metabolic activity in their active biomass. Diversity and crawling ciliates group have been shown as promising bioindicators of active biomass yield reduction. The identification of floc-forming bacteria in the control system suggested that oxic settling anoxic system will improve settling properties compared to a Conventional Activated Sludge process. PMID:26479432

  12. Accumulation of Settling Particles in Some Coral Reef Areas of Peninsular Malaysia

    International Nuclear Information System (INIS)

    The aim of this study was to determine the accumulation of settling particles in coral reefs of Peninsular Malaysia. Settling particles were collected from the coral reefs of Port Dickson, Pulau Langkawi, Pulau Tioman, Pulau Redang and Pulau Tinggi from 2005 to 2008. The average total settling particles in Pulau Langkawi and Port Dickson was 49.8 mg/ cm2/ day, while for Pulau Tioman, Pulau Redang, and Pulau Tinggi was 3.5 mg/ cm2/ day. The results showed that accumulations rate in west coast were higher than east coast of Peninsular Malaysia. However, Pulau Tioman in the east coast received high accumulations rate of settling particles in certain times of the year due to sediment resuspension at shallow reefs caused by high energy seasonal yearly wave and monsoon. (author)

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

    OpenAIRE

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

    2003-01-01

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

  14. Investigation of flow dynamics in aeration chamber in biological sewage treatment plant for selection of its optimal working parameters

    International Nuclear Information System (INIS)

    The subject of study was an activated sludge chamber in treatment station of petrochemical effluent. The chamber has been equipped with two surface aerators. A series of tracer evaluations of residence time distribution curves was performed for various immersion of aerators. The measurement of power consumption of aerators and COD reduction occurring in the chamber were recorded. The results obtained were applied to select the optimal working condition of the chamber. (author). 8 refs, 4 figs, 1 tabs

  15. CAVITATION CHARACTERISTICS OF HIGH VELOCITY FLOW WITH AND WITHOUT AERATION ON THE ORDER OF 50 m/s

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Experimental study of cavitation characteristics with and without aeration was conducted at the flow velocity 50m/s in the non-circulating type water tunnel in the Hydraulics Laboratory at Zhejiang University of Technology. Variations of pressure and cavitation number with air concentration, pressure waveforms as well as cavitation erosion level of concrete specimen with and without aeration were obtained. The effects of cavitation control by aeration were analyzed.

  16. Russian Pulsating Mixer Pump Deployment in the Gunite and Associated Tanks at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Hatchell, Brian K.; Lewis, Ben; Johnson, Marshall A.; Randolph, J. G.

    2001-03-01

    In FY 1998, Pulsating Mixer Pump (PMP) technology, consisting of a jet mixer powered by a reciprocating air supply, was selected for deployment in one of the Gunite and Associated Tanks at Oak Ridge National Laboratory (ORNL) to mobilize settled solids. The pulsating mixer pump technology was identified during FY 1996 and FY 1997 technical exchanges between the U.S. Department of Energy (DOE) Tanks Focus Area Retrieval and Closure program, the DOE Environmental Management International Programs, and delegates from Russia as a promising technology that could be implemented in the DOE complex. During FY 1997, the pulsating mixer pump technology, provided by the Russian Integrated Mining Chemical Company, was tested at Pacific Northwest National Laboratory (PNNL) to observe its ability to suspend settled solids. Based on the results of this demonstration, ORNL and DOE staff determined that a modified pulsating mixer pump would meet project needs for remote sludge mobilization of Gunite tank sludge and reduce the cost of operation and maintenance of more expensive mixing systems. The functions and requirements of the system were developed by combining the results and recommendations from the pulsating mixer pump demonstration at PNNL with the requirements identified by staff at ORNL involved with the remediation of the Gunite and Associated Tanks. The PMP is comprised of a pump chamber, check valve, a working gas supply pipe, a discharge manifold, and four jet nozzles. The pump uses two distinct cycles, fill and discharge, to perform its mixing action. During the fill cycle, vacuum is applied to the pump chamber by an eductor, which draws liquid into the pump. When the liquid level inside the chamber reaches a certain level, the chamber is pressurized with compressed air to discharge the liquid through the jet nozzles and back into the tank to mobilize sludge and settled solids.

  17. Thermal balance of aerated lagoons and waste stabilization ponds in temperate climate

    International Nuclear Information System (INIS)

    Very few studies have ever focused on the thermal balance of a wastewater treatment process, despite its major impact on various aspects of sanitary engineering, such as biological growth, oxygen transfer and, most importantly, purification kinetics. This lack of knowledge is particularly worrying for the design of aerated lagoons and waste stabilization ponds, since these two extensive treatment technologies are extremely dependent on climatic conditions and subject to high thermal variations. In temperate regions, a pond annual temperature range can even exceed 20 °C, while a 10 °C variation will induce a more than 60% drop or increase in its removal yield. Our paper intends to present a comprehensive temperature prediction model which accounts for the main heat loss and gain terms exchanged through the pond surface and walls. Our approach includes six different energy inputs and outputs, namely: solar radiation, air-water surface convection, atmospheric radiation, back surface radiation, evaporation and ground-water-walls convection. Each of these components was described extensively by means of a literature review of all previous efforts made to predict equilibrium temperature in lakes, rivers, salt-gradient solar ponds, cooling tanks, even outdoor pools. The best aspects of each prediction model were then incorporated into a new computer model developed as two different but complementary variants: one for steady-state conditions and the other for continuous and therefore also transient simulations. The main difference between these two approaches is that the first one neglects enthalpy variation while the second one takes the form of a differential equation, with basin temperatures being estimated by an iterative calculation procedure and a numerical integration method, respectively. Two hypotheses were necessary to develop this model. The first one posits that pond hydrodynamics correspond to completely mixed conditions. Such hydraulic behavior is extremely

  18. STUDIES ON THE EFFECT OF SETTLING TIME ON COLIFORM REDUCTION USING MORINGA OLEIFERA SEED POWDER

    OpenAIRE

    NWAIWU N.E.; LINGMU B.

    2011-01-01

    This paper studied the effect of settling time on microbe removal for low and medium turbidity pond (surface) water using Moringa oleifera seed powder. A high percentage of turbidity removal alongside a high percentage of microbial population removal with appropriate Moringa oleifera quantity was achieved. The turbidity removal for the low turbid water ranged between 80% and 96.3% within the 24 hours settling period while the microbial population removal efficiency ranged between 62.95% and ...

  19. Innovative tank emptying system for the retrieval of salt, sludge and IX resins from storage tanks of NPPs

    International Nuclear Information System (INIS)

    RWE NUKEM recently developed a new Tank Emptying System (TESY) for the extraction of stored radioactive boric acid/borate salt blocks, sludge and IX resin from NPP stainless steel tanks of several hundred cubic meters content in Russia. RWE NUKEM has chosen the emptying concept consisting of a tracked submersible vehicle ('Crawler'), with jet nozzles for solution, agitation and fluidization, and a suction head to pick up the generated solution or suspension respectively. With the employment of RWE NUKEM's TESY system, spent radioactive salt deposits, ion-exchange resins and sludge, can be emptied and transferred out of the tank. The sediment, crystallized and settled during storage, will be agitated with increased temperature and suitable pH value and then picked up in form of a suspension or solution directly at the point of mobilization. This new Tank Emptying System concept enables efficiently to retrieve stored salt and other sediment waste, reduces operating time, safes cost for spare parts, increases the safety of operation and minimizes radiation exposure to personnel. All emptying tasks are performed remotely from a panel board and TV monitor located in a central control room. The TESY system consists of the following main components: glove box, crawler, submersible pump, heater, TV camera and spot light, control panel and monitor, water separation and feed unit, sodium hydroxide dosing unit. The system is specially requested for the removal of more than 2,500 cubic meter salt solution generated from the dissolution of some 300 cubic meter crystallized salt deposit per tank and per year. The TESY system is able to dissolve efficiently the salts and retrieve solutions and other liquefied suspensions. TESY is adaptable to all liquid waste storage facilities and especially deployable for tanks with limited access openings (<550 mm)

  20. Effect of artificial aeration on the performance of vertical-flow constructed wetland treating heavily polluted river water.

    Science.gov (United States)

    Dong, Huiyu; Qiang, Zhimin; Li, Tinggang; Jin, Hui; Chen, Weidong

    2012-01-01

    Three lab-scale vertical-flow constructed wetlands (VFCWs), including the non-aerated (NA), intermittently aerated (IA) and continuously aerated (CA) ones, were operated at different hydraulic loading rates (HLRs) to evaluate the effect of artificial aeration on the treatment efficiency of heavily polluted river water. Results indicated that artificial aeration increased the dissolved oxygen (DO) concentrations in IA and CA, which significantly favored the removal of organic matter and NH(4+)-N. The DO grads caused by intermittent aeration formed aerobic and anoxic regions in IA and thus promoted the removal of total nitrogen (TN). Although the removal efficiencies of COD(Cr), NH(4+)-N and TN in the three VFCWs all decreased with an increase in HLR, artificial aeration enhanced the reactor resistance to the fluctuation of pollutant loadings. The maximal removal efficiencies of COD(Cr), NH(4+)-N and total phosphorus (TP) (i.e., 81%, 87% and 37%, respectively) were observed in CA at 19 cm/day HLR, while the maximal TN removal (i.e., 57%) was achieved in IA. Although the improvement of artificial aeration on TP removal was limited, this study has demonstrated the feasibility of applying artificial aeration to VFCWs treating polluted river water, particularly at a high HLR. PMID:22894092

  1. Optimizing aeration rates for minimizing membrane fouling and its effect on sludge characteristics in a moving bed membrane bioreactor

    International Nuclear Information System (INIS)

    Research highlights: → There is an optimum aeration rate in the MBMBR process compartments. → Optimum aeration rate maximizes nutrients removal. → Optimum aeration rate minimizes membrane fouling. → Both aeration rates in MBBR and membrane compartment can affect on membrane permeability. - Abstract: In MBR processes, sufficient aeration is necessary to maintain sustainable flux and to retard membrane fouling. Membrane permeability, sludge characteristics, nutrient removal and biomass growth at various air flow rates in the membrane and moving bed biofilm reactor (MBBR) compartments were studied in a pilot plant. The highest nitrogen and phosphorous removal rates were found at MBBR aeration rates of 151 and 85 L h-1 and a specific aeration demand per membrane area (SADm) of 1.2 and 0.4mair3 m-2 h-1, respectively. A linear correlation was found between the amount of attached biofilm and the nutrient removal rate. The aeration rate in the MBBR compartment and SADm significantly influenced the sludge characteristics and membrane permeability. The optimum combination of the aeration rate in the MBBR compartment and SADm were 151 L h-1 and 0.8-1.2mair3mmembrane-2 h-1, respectively.

  2. Nitrogen removal via short-cut simultaneous nitrification and denitrification in an intermittently aerated moving bed membrane bioreactor

    International Nuclear Information System (INIS)

    Highlights: → An intermittently aerated MBMBR was investigated to achieve SND via nitrite. → The intermittent-aeration strategy was an effective approach to achieve nitrition. → The activities of NOBs were inhibited under the intermittently aerated mode. → The intermittently aerated mode had no effect on the activities of AOBs. - Abstract: An intermittently aerated moving bed membrane bioreactor (MBMBR) was developed and crucial parameters affecting nitrogen removal from wastewater by simultaneous nitrification and denitrification via nitrite were investigated, without strict control of solids retention time. Changes in the microbiological community and distribution in the reactor were monitored simultaneously. The intermittent-aeration strategy proved effective in achieving nitrition and the chemical oxygen demand (COD) to total nitrogen (TN) ratio was an important factor affecting TN removal. In the MBMBR, the nitrite accumulation rate reached 79.4% and TN removal efficiency averaged at 87.8% with aeration 2 min/mix 4 min and an influent COD/TN ratio of 5. Batch tests indicated that under the intermittently aerated mode, nitrite-oxidizing bacteria (NOB) were not completely washed out from the reactor but NOB activity was inhibited. The intermittently aerated mode had no effect on the activities of ammonia-oxidizing bacteria. Fluorescence in situ hybridizations (FISH) results also suggested that NOBs remained within the system.

  3. Effect of artificial aeration on the performance of vertical-flow constructed wetland treating heavily polluted river water

    Institute of Scientific and Technical Information of China (English)

    Huiyu Dong; Zhimin Qiang; Tinggang Li; Hui Jin; Weidong Chen

    2012-01-01

    Three lab-scale vertical-flow constructed wetlands (VFCWs),including the non-aerated (NA),intermittently aerated (IA) and continuously aerated (CA) ones,were operated at different hydraulic loading rates (HLRs) to evaluate the effect of artificial aeration on the treatment efficiency of heavily polluted river water.Results indicated that artificial aeration increased the dissolved oxygen (DO) concentrations in IA and CA,which significantly favored the removal of organic matter and NH4+-N.The DO grads caused by intermittent aeration formed aerobic and anoxic regions in IA and thus promoted the removal of total nitrogen (TN).Although the removal efficiencies of CODcr,NH4+-N and TN in the three VFCWs all decreased with an increase in HLR,artificial aeration enhanced the reactor resistance to the fluctuation of pollutant loadings.The maximal removal efficiencies of CODcr,NH4+-N and total phosphorus (TP) (i.e.,81%,87% and 37%,respectively) were observed in CA at 19 cm/day HLR,while the maximal TN removal (i.e.,57%) was achieved in IA.Although the improvement of artificial aeration on TP removal was limited,this study has demonstrated the feasibility of applying artificial aeration to VFCWs treating polluted eiver water,particularly at a high HLR.

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

    DEFF Research Database (Denmark)

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

    2003-01-01

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

  5. Impact of post-infiltration soil aeration at different growth stages of sub-surface trickle-irrigated tomato plants

    Science.gov (United States)

    Li, Yuan; Jia, Zong-xia; Niu, Wen-Quan; Wang, Jing-wei

    2016-07-01

    Sensitivity to low rhizosphere soil aeration may change over time and therefore plant response may also depend on different growth stages of a crop. This study quantified effects of soil aeration during 5 different periods, on growth and yield of trickle-irrigated potted single tomato plants. Irrigation levels were 0.6 to 0.7 (low level) or 0.7 to 0.8 (high level) of total water holding capacity of the pots. Soil was aerated by injecting 2.5 l of air into each pot through the drip tubing immediately after irrigation. Fresh fruit yield, above ground plant dry weight, plant height, and leaf area index response to these treatments were measured. For all these 4 response variables, means of post-infiltration aeration between 58 to 85 days after sowing were 13.4, 43.5, 13.7, and 37.7% higher than those for the non-aerated pots, respectively. The results indicated that: post-infiltration soil aeration can positively impact the yield and growth of sub-surface trickle-irrigated potted tomato plants; positive effects on plant growth can be obtained with aeration during the whole growth period or with aeration for partial periods; positive growth effects of partial periods of aeration appears to persist and result in yield benefit.

  6. Project Specific Quality Assurance Plan Project (QAPP) W-211 Initial Tank Retrieval Systems (ITRS)

    International Nuclear Information System (INIS)

    This Quality Assurance Program Plan (QAPP) provides information on how the Project Hanford Quality Assurance Program is implemented by CH2M HILL Hanford Group Inc (CHG) for managing the Initial Tank Retrieval Systems (ITRS), Project W-211. This QAPP is responsive to the CHG Quality Assurance Program Description (QAPD) (LMH-MP-599) which provides direction for compliance to 10 CFR 830 120, ''Nuclear Safety Management, Quality Assurance Requirements'', and DOE Order 5700 6C, ''Quality Assurance'' Project W-211 modifies existing facilities and provides systems for retrieval of radioactive wastes from selected double-shell tanks (DST). The contents of these tanks are a combination of supernatant liquids and settled solids. To retrieve waste from the tanks, it is first necessary to mix the liquid and solids prior to transferring the slurry to alternative storage or treatment facilities. The ITRS will provide systems to mobilize the settled solids and transfer the wastes out of the tanks. In so doing, ITRS provides feed for future processing plants, allows for consolidation of tank solids to manage space within existing DST storage capacity, and supports continued safe storage of tank waste. This project includes the design, procurement, construction, startup and turnover of these retrieval systems This QAPP identifies organizational structures and responsibilities. Implementing procedures used by CHG project management can be found in the CHG Quality Assurance Program (CHG QAP) Implementation Matrix located in HNF-IP-0842, Volume XI, Attachment Proposed verification and inspection activities for critical items within the scope of project W-211 are identified in Attachment 1 W-211. Project participants will identify the implementing procedures used by their organization within their QAF'Ps. This project specific QAPP is used to identify requirements in addition to the QAPD and provide, by reference, additional information to other project documents

  7. In situ determination of flocculated suspended material settling velocities and characteristics using a floc camera

    Science.gov (United States)

    Schoellhamer, David H.; Haught, Dan; Manning, Andrew

    2012-01-01

    Estimates of suspended sediment settling are necessary for numerical sediment models, water quality studies, and rehabilitation of coastal ecosystems. Settling of cohesive sediment, which is common in estuaries, is more difficult to quantify than noncohesive sediment because of flocculation. Flocs are composed of an aggregation of finer silts, clays, and organic material. Floc characteristics, such as the diameter, density, porosity, and water content determine floc settling velocities. A floc camera provides the ability to capture the settling velocities and other desired characteristics of individual flocs in situ. Water samples taken using a Van Dorn sampler are immediately subsampled using a pipette and transferred to the floc camera. The Perspex settling column is outfitted with a LED backlighting to distinguish flocs. The floc camera’s high pixel and temporal resolution allows image analysis software to detect individual flocs and process floc statistics per image. Observed changes in floc location with respect to time presents a way of calculating settling velocities. This work presents results of validation tests with known sediment size distributions and of deployment of the camera during a field study.

  8. Direct numerical simulation of finite sized particles settling for high Reynolds number and dilute suspension

    International Nuclear Information System (INIS)

    Highlights: • It is observed that particle clustering is inversely proportional to Reynolds number. • A better relation is proposed for average settling velocity in dilute suspension. • Froude number and power spectrum can be used for estimating particle clustering. • For φ = 0.03 and 0.05, unfavorable wake structures reduces the formation of close particles pairs. - Abstract: Finite sized particles settling under the action of gravity are investigated by immersed boundary method for dilute suspensions and low to high range of Reynolds number. The Reynolds number based on the terminal velocity of a single particle is varied from 1 to 300 and the solid volume fraction (φ) is varied from 0.005 to 0.05. The studied range of Reynolds number corresponds from streamlined flow to downstream vortex shedding flow for single particle. For φ = 0.005, 0.01 and high Reynolds number (Re ≧ 175), settling particles clusters due to the entrapment in high fluid shear regions. However for Re = 50 and 100, particles form separated pairs due to relatively weak strength of wakes that promote to drafting–kissing and tumbling scenario. These particle structures at high Reynolds number changes the settling behaviors of particles e.g. increase in the settling velocity and fluid velocity fluctuations. For φ = 0.03, 0.05, hindered settling effects dominate and reduce the effects of particles clustering due to Reynolds number

  9. Food Poverty Profile in Settled Pastrol Households of Lowland Marsabit: Evidence from Micro Data

    International Nuclear Information System (INIS)

    Frequent and severe droughts experienced in ASALs push pastoralists out of the traditional livestock monoculture, which together with the growing human population lead to increasing settlement. Unlike nomads who access traditional livestock foods at all times, settled households have limited access, which does not guarantee their food security. To achieve the food security the settled households supplement limited livestock foods with market foods. High demand for market foods increases demand for money and since pastoral communities have limited income-generating opportunities, many households are relegated to below food poverty line. Most studies on food security in ASALs focus on livestock productivity without considering that settled households depend, to a small extent, on livestock foods. Since settled households experience a lot of socio-economic changes,their food security status needs to be appropriately evaluated. The aim of this study t is to establish the food poverty profile of the settled households and recommend appropriate measures for attaining food security in the settled households

  10. Laboratory Scale Study of Activated Sludge Process in Jet Loop Reactor for Waste WaterTreatment

    OpenAIRE

    M. S. Patil; G. A. Usmani

    2014-01-01

    The present study was undertaken to evaluate the feasibility of Activated Sludge Process (ASP) for the treatment of synthetic wastewater and to develop a simple design criteria under local conditions.A laboratory scale Compact jet loop reactor model comprising of an aeration tank and final clarifier was used for this purpose.Settled synthetic wastewater was used as influent to the aeration tank. The Chemical Oxygen Demand (COD) of the influent and effluent was measured to find...

  11. Final Report - Crystal Settling, Redox, and High Temperature Properties of ORP HLW and LAW Glasses, VSL-09R1510-1, Rev. 0, dated 6/18/09

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A.; Wang, C.; Gan, H.; Pegg, I. L.; Chaudhuri, M.; Kot, W.; Feng, Z.; Viragh, C.; McKeown, D. A.; Joseph, I.; Muller, I. S.; Cecil, R.; Zhao, W.

    2013-11-13

    The radioactive tank waste treatment programs at the U. S. Department of Energy (DOE) have featured joule heated ceramic melter technology for the vitrification of high level waste (HLW). The Hanford Tank Waste Treatment and Immobilization Plant (WTP) employs this same basic technology not only for the vitrification of HLW streams but also for the vitrification of Low Activity Waste (LAW) streams. Because of the much greater throughput rates required of the WTP as compared to the vitrification facilities at the West Valley Demonstration Project (WVDP) or the Defense Waste Processing Facility (DWPF), the WTP employs advanced joule heated melters with forced mixing of the glass pool (bubblers) to improve heat and mass transport and increase melting rates. However, for both HLW and LAW treatment, the ability to increase waste loadings offers the potential to significantly reduce the amount of glass that must be produced and disposed and, therefore, the overall project costs. This report presents the results from a study to investigate several glass property issues related to WTP HLW and LAW vitrification: crystal formation and settling in selected HLW glasses; redox behavior of vanadium and chromium in selected LAW glasses; and key high temperature thermal properties of representative HLW and LAW glasses. The work was conducted according to Test Plans that were prepared for the HLW and LAW scope, respectively. One part of this work thus addresses some of the possible detrimental effects due to considerably higher crystal content in waste glass melts and, in particular, the impact of high crystal contents on the flow property of the glass melt and the settling rate of representative crystalline phases in an environment similar to that of an idling glass melter. Characterization of vanadium redox shifts in representative WTP LAW glasses is the second focal point of this work. The third part of this work focused on key high temperature thermal properties of

  12. Optical Cryogenic Tank Level Sensor

    Science.gov (United States)

    Duffell, Amanda

    2005-01-01

    Cryogenic fluids play an important role in space transportation. Liquid oxygen and hydrogen are vital fuel components for liquid rocket engines. It is also difficult to accurately measure the liquid level in the cryogenic tanks containing the liquids. The current methods use thermocouple rakes, floats, or sonic meters to measure tank level. Thermocouples have problems examining the boundary between the boiling liquid and the gas inside the tanks. They are also slow to respond to temperature changes. Sonic meters need to be mounted inside the tank, but still above the liquid level. This causes problems for full tanks, or tanks that are being rotated to lie on their side.

  13. Development of a stepwise aeration control strategy for efficient docosahexaenoic acid production by Schizochytrium sp.

    Science.gov (United States)

    Ren, Lu-Jing; Ji, Xiao-Jun; Huang, He; Qu, Liang; Feng, Yun; Tong, Qian-Qian; Ouyang, Ping-Kai

    2010-08-01

    The effect of aeration on the performance of docosahexaenoic acid (DHA) production by Schizochytrium sp. was investigated in a 1,500-L bioreactor using fed-batch fermentation. Six parameters, including specific growth rate, specific glucose consumption rate, specific lipid accumulation rate, cell yield coefficient, lipid yield coefficient, and DHA yield coefficient, were used to understand the relationship between aeration and the fermentation characteristics. Based on the information obtained from the parameters, a stepwise aeration control strategy was proposed. The aeration rate was controlled at 0.4 volume of air per volume of liquid per minute (vvm) for the first 24 h, then shifted to 0.6 vvm until 96 h, and then switched back to 0.4 vvm until the end of the fermentation. High cell density (71 g/L), high lipid content (35.75 g/L), and high DHA percentage (48.95%) were achieved by using this strategy, and DHA productivity reached 119 mg/L h, which was 11.21% over the best results obtained by constant aeration rate. PMID:20445973

  14. Aeration strategy: a need for very high ethanol performance in Saccharomyces cerevisiae fed-batch process.

    Science.gov (United States)

    Alfenore, S; Cameleyre, X; Benbadis, L; Bideaux, C; Uribelarrea, J-L; Goma, G; Molina-Jouve, C; Guillouet, S E

    2004-02-01

    In order to identify an optimal aeration strategy for intensifying bio-fuel ethanol production in fermentation processes where growth and production have to be managed simultaneously, we quantified the effect of aeration conditions--oxygen limited vs non limited culture (micro-aerobic vs aerobic culture)--on the dynamic behaviour of Saccharomyces cerevisiae cultivated in very high ethanol performance fed-batch cultures. Fermentation parameters and kinetics were established within a range of ethanol concentrations (up to 147 g l(-1)), which very few studies have addressed. Higher ethanol titres (147 vs 131 g l(-1) in 45 h) and average productivity (3.3 vs 2.6 g l(-1) h(-1)) were obtained in cultures without oxygen limitation. Compared to micro-aerobic culture, full aeration led to a 23% increase in the viable cell mass as a result of the concomitant increase in growth rate and yield, with lower ethanol inhibition. The second beneficial effect of aeration was better management of by-product production, with production of glycerol, the main by-product, being strongly reduced from 12 to 4 g l(-1). We demonstrate that aeration strategy is as much a determining factor as vitamin feeding (Alfenore et al. 2002) in very high ethanol performance (147 g l(-1) in 45 h) in order to achieve a highly competitive dynamic process. PMID:12879304

  15. Nitrogen transformations and retention in planted and artificially aerated constructed wetlands.

    Science.gov (United States)

    Maltais-Landry, Gabriel; Maranger, Roxane; Brisson, Jacques; Chazarenc, Florent

    2009-02-01

    Nitrogen (N) processing in constructed wetlands (CWs) is often variable, and the contribution to N loss and retention by various pathways (nitrification/denitrification, plant uptake and sediment storage) remains unclear. We studied the seasonal variation of the effects of artificial aeration and three different macrophyte species (Phragmites australis, Typha angustifolia and Phalaris arundinacea) on N processing (removal rates, transformations and export) using experimental CW mesocosms. Removal of total nitrogen (TN) was higher in summer and in planted and aerated units, with the highest mean removal in units planted with T. angustifolia. Export of ammonium (NH(4)(+)), a proxy for nitrification limitation, was higher in winter, and in unplanted and non-aerated units. Planted and aerated units had the highest export of oxidized nitrogen (NO(y)), a proxy for reduced denitrification. Redox potential, evapotranspiration (ETP) rates and hydraulic retention times (HRT) were all predictors of TN, NH(4)(+) and NO(y) export, and significantly affected by plants. Denitrification was the main N sink in most treatments accounting for 47-62% of TN removal, while sediment storage was dominant in unplanted non-aerated units and units planted with P. arundinacea. Plant uptake accounted for less than 20% of the removal. Uncertainties about the long-term fate of the N stored in sediments suggest that the fraction attributed to denitrification losses could be underestimated in this study. PMID:19036399

  16. [Effect of Intermittent Aeration on Nitrogen Removal Efficiency in Vertical Subsurface Flow Constructed Wetland].

    Science.gov (United States)

    Wang, Jian; Li, Huai-zheng; Zhen, Bao-chong; Liu, Zhen-dong

    2016-03-15

    One-stage vertical subsurface flow constructed wetlands (CWs) were used to treat effluent from grit chamber in municipal wastewater treatment plant. The CW was divided into aerobic zone and anoxic zone by means of raising the effluent level and installing a perforated pipe. Two parameters (the ratio of aeration time and nonaeration time, aeration cycle) were optimized in the experiment to enhance nitrogen removal efficiency. The results suggested that the removal rates of COD and NH₄⁺-N increased while TN showed a trend of first increasing and then decreasing with the increasing ratio. When the ratio was 3:1, the C/N value in the anoxic zone was 4. 8. And the TN effluent concentration was 15.8 mg · L⁻¹ with the highest removal rate (62.1%), which was increased by 12.7% compared with continuous aeration. As the extension of the aeration cycle, the DO effluent concentration as well as the removal rates of COD and NH: -N declined gradually. The TN removal rate reached the maximum (65.5%) when the aeration cycle was 6h. However, the TN removal rate dropped rapidly when the cycle exceeded the hydraulic retention time in the anoxic zone. PMID:27337890

  17. Aerated Shewanella oneidensis in continuously fed bioelectrochemical systems for power and hydrogen production.

    Science.gov (United States)

    Rosenbaum, Miriam; Cotta, Michael A; Angenent, Largus T

    2010-04-01

    We studied the effects of aeration of Shewanella oneidensis on potentiostatic current production, hydrogen production in a microbial electrolysis cell, and electric power generation in a microbial fuel cell (MFC). The potentiostatic performance of aerated S. oneidensis was considerably enhanced to a maximum current density of 0.45 A/m(2) or 80.3 A/m(3) (mean: 0.34 A/m(2), 57.2 A/m(3)) compared to anaerobically grown cultures. Biocatalyzed hydrogen production rates with aerated S. oneidensis were studied within the applied potential range of 0.3-0.9 V and were highest at 0.9 V with 0.3 m(3) H(2)/m(3) day, which has been reported for mixed cultures, but is approximately 10 times higher than reported for an anaerobic culture of S. oneidensis. Aerated MFC experiments produced a maximum power density of 3.56 W/m(3) at a 200-Omega external resistor. The main reasons for enhanced electrochemical performance are higher levels of active biomass and more efficient substrate utilization under aerobic conditions. Coulombic efficiencies, however, were greatly reduced due to losses of reducing equivalents to aerobic respiration in the anode chamber. The next challenge will be to optimize the aeration rate of the bacterial culture to balance between maximization of bacterial activation and minimization of aerobic respiration in the culture. PMID:19998276

  18. Optimisation of pressure aeration systems in waste water treatment; Optimierung von Druckbelueftungssystemen in der Abwasserbehandlung

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.

    2002-07-01

    This paper investigates, evaluates and places in context a diverse range of factors impacting on the performance of aerator elements used in the pressure aeration of wastewater treatment. To perform the investigation, a large-scale test basin and column were installed to allow oxygen transfer tests to be conducted under identical and hence reproducible boundary conditions. In addition to standard model aerators, numerous prototypes of disc, pipe and hose aerators were produced which differed in individual design characteristics or other properties. The various designs were installed in the experimental set-up and their performance measured by means of oxygen transfer tests using the desorption method. Based on these findings as well as on the detailed theoretical principles and the empirical investigations, recommendations were drawn up for the optimisation of pressurised aerator systems which will allow a significant reduction in the required volumes of air and hence in the cost of electricity for the compressors and blowers without a reduction in performance. (orig.)

  19. Nitrogen removal in the bioreactor landfill system with intermittent aeration at the top of landfilled waste

    International Nuclear Information System (INIS)

    High ammonia concentration of recycled landfill leachate makes it very difficult to treat. In this work, a vertical aerobic/anoxic/anaerobic lab-scale bioreactor landfill system, which was constructed by intermittent aeration at the top of landfilled waste, as a bioreactor for in situ nitrogen removal was investigated during waste stabilization. Intermittent aeration at the top of landfilled waste might stimulate the growth of nitrifying bacteria and denitrifying bacteria in the top and middle layers of waste. The nitrifying bacteria population for the landfill bioreactor with intermittent aeration system reached between106 and 108 cells/dry g waste, although it decreased 2 orders of magnitude on day 30, due to the inhibitory effect of the acid environment and high organic matter in the landfilled waste. The denitrifying bacteria population increased by between 4 and 13 orders of magnitude compared with conventional anaerobic landfilled waste layers. Leachate NO3--N concentration was very low in both two experimental landfill reactors. After 105 days operation, leachate NH4+-N and TN concentrations for the landfill reactor with intermittent aeration system dropped to 186 and 289 mg/l, respectively, while they were still kept above 1000 mg/l for the landfill reactor without intermittent aerobic system. In addition, there is an increase in the rate of waste stabilization as well as an increase of 12% in the total waste settlement for the landfill reactor with intermittent aeration system

  20. Influence of Gabcikovo hydro power structures on the dynamics of water in the aeration zone

    International Nuclear Information System (INIS)

    For the quantification of the influence of ground water level changes and fluctuation on water dynamics in the aeration zone the three following characteristics have been choseN: 1) the course of cumulative water content in the aeration zone, monitored during the period 1990 to 1994; 2) quarterly averages of water content in the aeration zone in the zone in the period 1990 to 1994; 3) the quantification of the participation of individual soil horizons on cumulative water content in the aeration zone in given time intervals for selected typical monitored locations. The negative changes of the ground water after setting the Gabcikovo structures into operation as predicted by some authors, were not confirmed in the monitoring period (two years prior to setting the Gabcikovo structures into operation, one year during the transitional period, and two years after damming) and were not negatively reflected in the changes of water content in the soil zone of aeration. (authors). 1 tabs., figs., 1 map, 21 refs