scholarly journals Design, simulation, and laboratory test of a single sludge drainage pipe for wastewater treatment sedimentation tank

2020 ◽  
Vol 82 (5) ◽  
pp. 905-917
Author(s):  
Hao Feilin ◽  
Shen Mingwei
Keyword(s):  
Wastewater Treatment ◽  
Fluid Dynamic ◽  
Fluid Velocity ◽  
Drainage System ◽  
Multiphase Model ◽  
Two Factors ◽  
Mass Flowrate ◽  
Drainage Pipe ◽  
Single Pipe ◽  
Drainage Ratio

Abstract This study develops a novel design scheme based on engineering fluid mechanics for the single-pipe-type sludge drainage mechanism of sedimentation tanks in the wastewater treatment industry. A laboratory-scale clarifier is fabricated for experimental verification. Sludge drainage ratio and suspended solids (SS) of inflow are selected as two factors for laboratory experiments, and SS values are measured to evaluate the performance of the sludge drainage pipe. Experiment data show that the designed single sludge drainage pipe can successfully achieve the supposed task with a coefficient of variation (CV) of SS less than 8.5%. The variation scope of CV from 1.5% to 8.3% suggests that the sludge drainage performance is relatively steady. Nine sets of 3D computational fluid dynamic (CFD) simulations, which is based on the inhomogeneous Eulerian–Eulerian multiphase model, were conducted for a comprehensive exploration and assessment. Results reveal noticeable deviations of the characteristics of the fluid in the outermost orifice of the sludge drainage pipe from the designed value. Although the fluid velocity through each orifice is matched with the designed values, the mass flowrate differs with a maximum of four times the designed value and a standard deviation of 0.4 of hole among the nine simulations. This study also suggests some considerations in the design process and routine operation of the single-pipe-type sludge drainage system.

Comprehensive Planning of Urban Drainage and Wastewater Treatment

1993 ◽  
Vol 27 (12) ◽  
pp. 205-208
Author(s):  
Dirk-Th Kollatsch
Keyword(s):  
Wastewater Treatment ◽  
Transport Model ◽  
Drainage System ◽  
Simulation Models ◽  
Urban Drainage ◽  
Sewer Systems ◽  
Priority Task ◽  
Treatment Facilities ◽  
Receiving Waters ◽  
Pollution Impacts

For upgrading the urban drainage system (UDS) the reduction of pollution impacts is the priority task concerning the environmental protection of the receiving waters. With simulation models the interactions between surface, sewer systems, overflow structures and treatment facilities within the UDS can be shown. Models to simulate the pollutant impacts, transport and the effects on the receiving waters are available. In a first step a pollutant transport model of sewer systems and a model to simulate the wastewater treatment processes are connected. With these models the efficiency of upgrading measures can be checked in all parts of urban drainage systems.

Integrated modelling: comparison of state variables, processes and parameters in sewer and wastewater treatment plant models

1997 ◽  
Vol 36 (5) ◽  
pp. 373-380 ◽  
Author(s):  
C. Fronteau ◽  
W. Bauwens ◽  
P.A. Vanrolleghem
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Drainage System ◽  
Integrated Modelling ◽  
Urban Drainage ◽  
State Variables ◽  
Sewer System ◽  
Wastewater Treatment Process ◽  
Urban Drainage System

All the parts of an urban drainage system, i.e. the sewer system, the wastewater treatment plant (WWTP) and the river, should be integrated into one single model to assess the performance of the overall system and for the development of design and control strategies assisting in its sustainable and cost effective management. Existing models for the individual components of the system have to be merged in order to develop the integrated tool. One of the problems arising from this methodology is the incompatibility of state variables, processes and parameters used in the different modelling approaches. Optimisation of an urban drainage system, and of the wastewater treatment process in particular, requires a good knowledge of the wastewater composition. As important transformations take place between the emission from the household and the arrival at the treatment facility, sewer models should include these transformations in the sewer system. At present, however, research is still needed in order to increase our knowledge of these in-sewer processes. A comparison of the state variables, processes and parameters has been carried out in both sewer models (SMs) and activated sludge models (ASMs). An ASM approach is used for the description of reactions in sewer models. However, a difference is found in the expression for organic material (expressed in terms of BOD) and heterotrophic biomass is absent as a state variable, resulting in differences in processes and parameters. Reconciliation of both the models seems worthwhile and a preliminary solution is suggested in this paper.

Study on a sequencing batch membrane bioreactor for wastewater treatment

2000 ◽  
Vol 41 (10-11) ◽  
pp. 227-234 ◽  
Author(s):  
W.J. Ng ◽  
S.L. Ong ◽  
M.J. Gomez ◽  
J.Y. Hu ◽  
X.J. Fan
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Extended Period ◽  
Cod Removal ◽  
Nitrification Inhibition ◽  
Test Results ◽  
Two Factors ◽  
High Feed ◽  
Average Flux

This study investigated the effect of MLSS concentration in a sequencing batch membrane bioreactor on COD and nitrogen removal as well as flux. Two values of MLSS (5 g/l and 10 g/l) were investigated in this study. The strength of the feed was varied to achieve a target F/M ratio of 0.5 based on COD. Accordingly, the concentration of COD was determined as 3.5 and 7.0 g/l for the 5 and 10 g/l MLSS targets, respectively. The test results showed that an average COD removal of 98.5% was achievable. However, it was noted that nitrification inhibition occurred. Nitrification inhibition occurred because of two factors, namely high NH4+–N concentration and high DO demand. High NH4+–N in the feed led to the inhibition of nitratation and thus high nitrites are found in the effluent. High DO demand due to high feed COD concentration led to an extended period with low DO levels inside the reactor thus retarding the conversion of NH4+–N. The increase in the MLSS concentration from 5 to 10 g/l led to a decrease in the average flux from11.1 l/m2 · h to 9.6 l/m2 · h. An increase in aeration, from 2.0 to 8.0 l/min, did not lead to any significant improvement in terms of fouling.

Improvement on acoustic performance of the accumulator of double-cylinder rotary compressors

2007 ◽  
Vol 221 (11) ◽  
pp. 1391-1396 ◽  
Author(s):  
Z Y Huang ◽  
W K Jiang ◽  
C H Liu ◽  
H S Jin ◽  
Y Zhou
Keyword(s):  
Noise Level ◽  
Fluid Dynamic ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Rotary Compressor ◽  
Acoustic Performance ◽  
Wall Pressure Fluctuations ◽  
Large Pressure ◽  
Flow Phase ◽  
Single Pipe

Since the accumulator is one of main contributors to the overall noise level of the rotary compressor, research on the acoustic performance of accumulators is essential. Numerical analysis based on the computational fluid dynamic method shows that large pressure fluctuations are caused mainly by periodic rotating piston. The idea that the flow phase differences of two pipes could be utilized for suppressing fluctuations is proposed. The double standpipes of an accumulator are changed to the single pipe with two branches and each branch is connected to the inlet of the compressor. Flow structures and wall pressure fluctuations for the two configurations are computed. Computational results show that wall pressure pulsations of the new accumulator are obviously lower than that of the original. The acoustic experiments were carried out under the real working conditions. Compared with the original, the new accumulator shows that the overall noise level is reduced about 1.2 dB(A) and the sound spectrum levels are also lower in a wide frequency domain, which validate the numerical and theoretical analysis.

Application of Genetic Algorithm to Prediction of Artery Geometry

2007 ◽  
Author(s):  
M. Himeno ◽  
S. Noda ◽  
R. Himeno ◽  
K. Fukasaku
Keyword(s):  
Fluid Dynamics ◽  
Genetic Algorithm ◽  
Fluid Dynamic ◽  
Flow Analysis ◽  
Two Dimensional ◽  
Multi Objective Optimization ◽  
Curved Artery ◽  
Two Factors ◽  
Blood Flow Analysis ◽  
Significant Factors

We used the genetic algorithm (GA) and two-dimensional blood flow analysis to examine the fluid dynamic and engineering factors in multi-objective optimization of blood tubes (vessels). We supposed two factors from fluid dynamics: the wall shear stress (WSS) and the pressure loss, and one materials saving factor: the artery length. As a result, we could get the optimum shapes for each factor. In the case of WSS and artery length, both smoothly curved artery shapes and shapes with bulges were obtained as lower WSS cases. The shapes with bulges were similar to those of aneurysms. In this case, it was found that the WSS increases after the bulge is removed. This means bulges in artery vessel areas with higher WSSs effectively reduce the WSS value. Only the case of WSS and artery length produced a shape like an aneurysm. These results indicate that WSS and artery length are significant factors in determining artery shape.

scholarly journals Pengaruh Aerasi Dalam Constructed Wetland Pada Pengolahan Air Limbah Domestik

2018 ◽  
Vol 16 (2) ◽  
pp. 155
Author(s):  
Euis Nurul Hidayah ◽  
Andrysah Djalalembah ◽  
Gina Aprilliana Asmar ◽  
Okik Hendriyanto Cahyonugroho
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetland ◽  
Drainage System ◽  
Domestic Wastewater ◽  
Septic Tank ◽  
Source Water ◽  
Treatment Technology ◽  
Detention Time ◽  
Domestic Wastewater Treatment ◽  
Natural Treatment

ABSTRAKPenanganan air limbah domestik Kota Surabaya selama ini dilakukan dengan 2 cara, yakni untuk blackwater dialirkan ke tangki septik dan greywater dialirkan ke drainase tanpa pengolahan. Hal ini menyebabkan peningkatan pencemar pada sungai sebagai air baku. Salah satu teknologi alternatif yang dapat diaplikasikan dengan mudah dan rendah biaya operasional dibanding pengolahan air limbah lainnya adalah constructed wetland dengan menggunakan tanaman Iris pseudoacorus sebagai kombinasi pengolahan biofilter dan proses fitoteknologi. Penelitian ini dilakukan untuk mengetahui efisiensi dari constructed wetland dengan tanaman Iris pseudoacorus untuk mengolah limbah domestik, serta menentukan bagaimana pengaruh dari adanya aerasi dan pengaruh waktu tinggal pada sistem constructed wetland dalam menurunkan bahan organik dan nitrogen pada air limbah. Penelitian ini dilakukan dalam skala uji laboratorium menggunakan reaktor berkapasitas 30 liter. Air limbah dialirkan pada reaktor dengan waktu tinggal 2 hari dan 3 hari, dengan variasi aerasi dan efisiensi pencemar diukur dengan parameter BOD, dan ammonia. Hasil penelitian ini menunjukan bahwa kemampuan penyisihan BOD, dan ammonia dari limbah air domestik oleh reaktor constructed wetland dengan tambahan aerasi dan waktu tinggal selama 4 hari sangat efektif. Reaktor ini mampu menurunkan nilai BOD hingga 96% dan nilai ammonia sebesar 97%.ABSTRACTWastewater domestic in Surabaya City has been treated in two methods, including septic tank for blackwater and directly discharged into drainage system for greywater. This caused an increasing pollutant loading in source water. Constructed wetland with Iris pseudoacorus, one of the alternative natural treatment technology through biofilter and phytotechnology process, could be applied easily and less costly to other treatment. This research was conducted to know the efficiency of constructed wetland with Iris pseudoacorus in domestic wastewater treatment, and to reveal the effect of aeration and detention time in reducing organic and nitrogen content in domestic wastewater. Experiment has been conducted on a laboratory scale of continue aerated reactor and without aeration as control reactor. Detention time (days) 2 and 3 was setup, then sample was taken for BOD and ammonia measurement. The results indicated that constructed wetland with aeration and detention time 4 days had a higher performance to remove BOD up to 96% and ammonia up to 97% than without aeration and less than 4 days process.Keywords: Domestic Wastewater, Constructed Wetland, Phytotechnology, Iris pseudoacorus, Aeration.Sitasi: Hidayah, E. N., Djalalembah, A., Asmar, G.A. dan Cahyonugroho, G.A. (2018). Pengaruh aerasi dalam constructed wetland pada pengolahan air limbah domestik. Jurnal Ilmu Lingkungan, 16(2),155-161, doi:10.14710/jil.16.2.155-161

Performance Optimization of Building Integrated-Mounted Wind Turbine

2012 ◽  
Vol 260-261 ◽  
pp. 69-76 ◽  
Author(s):  
Marco Milanese ◽  
Arturo de Risi ◽  
Domenico Laforgia
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Performance Optimization ◽  
Fluid Dynamic ◽  
Geometrical Parameters ◽  
Horizontal Axis Wind Turbine ◽  
Energy Devices ◽  
Two Factors ◽  
High Turbulence ◽  
Computation Fluid Dynamic

Building integrated-mounted wind turbine (BUWT) is one of the most promising renewable energy devices. However, this renewable energy technology is not fully spread principally due to two factors such as uncertainty in the prediction of wind velocity and high turbulence intensity around the building. In this work, the Taguchi method and the analysis of variance (ANOVA) on a horizontal-axis wind turbine has been applied, to study the influence of geometrical parameters such as building depth, width and height, as well as turbine position on the roof and turbine height. To evaluate the above-cited effects, the airflow around an isolated building of parametrical dimension has been simulated using a Computation Fluid Dynamic (CFD) code calibrated against experimental data in a previous paper from the authors. The results reported in the present paper outline the relative effects of the main building geometrical parameters on the performance of a rooftop installed wind turbine and establish basic guidelines for the optimal location of such turbines.

The Instability of a Flexible Sheet in Uniform Parallel Flow

2007 ◽  
Author(s):  
Michael T. Morris-Thomas ◽  
Sverre Steen
Keyword(s):  
Spectral Method ◽  
Ideal Fluid ◽  
Flow Instability ◽  
Fluid Dynamic ◽  
Fluid Velocity ◽  
Critical Value ◽  
Elastic Model ◽  
Elastic Instability ◽  
Mass Ratio ◽  
Unique Aspect

When a flexible sheet immersed in a fluid is under the influence of uniform flow, instability can arise when the fluid velocity reaches some critical value. The fluid-elastic instability known as flutter is the focus of this present work. We present a fluid-elastic model for a flexible sheet whereby the fluid dynamic lift is accounted for by the classical slender body approximation of Lighthill [1] for an ideal fluid. We describe aspects of the system in terms of a mass ratio α and a tension to flexural ratio γ. The model is solved by a spectral method to determine the fluid velocity and frequency at which instability occurs. In addition, we consider the fluid friction and damping on the response of the flexible sheet. Moreover, we compare predictions for the flutter velocity and frequency with published results. The unique aspect of this work is an investigation into the effect of additional tension, in the form of the ratio γ, on stability.

scholarly journals High-beta turbulence in two-dimensional magnetohydrodynamics

1976 ◽  
Vol 16 (2) ◽  
pp. 181-191 ◽  
Author(s):  
David Fyfe ◽  
David Montgomery
Keyword(s):  
Magnetic Fields ◽  
Turbulent Flows ◽  
Fluid Dynamic ◽  
Fluid Velocity ◽  
Navier Stokes ◽  
Magnetic Islands ◽  
Dissipation Energy ◽  
Energy Cascades ◽  
Wide Range ◽  
Current Filaments

Incompressible turbulent flows are investigated in the framework of ideal magnetohydrodynamics. All the field quantities vary with only two spatial dimensions. Equilibrium canonical distributions are determined in a phase space whose co-ordinates are the real and imaginary parts of the Fourier coefficients for the field variables. In the geometry considered, the magnetic field and fluid velocity have variable x and y components, and all field quantities are independent of z. Three constants of the motion are found (one of them new) which survive the truncation in Fourier space and permit the construction of canonical distributions with three independent temperatures. Spectral densities are calculated. One of the more novel physical effects is the appearance of macroscopic structures involving long wavelength, self-generated, magnetic fields (‘magnetic islands’) for a wide range of initial parameters. Current filaments show a tendency toward consolidation in much the same way that vorticity filaments do in the guiding-centre plasma case. In the presence of finite dissipation, energy cascades to higher wavenumbers can be accompanied by vector potential cascades to lower wavenumbers, in much the same way as, in the fluid dynamic (Navier-Stokes) case, energy cascades to lower wavenumbers accompany enstrophy cascades to higher wavenumbers. It is suggested that the techniques may be relevant to theories of the magnetic dynamo problem and to the generation of megagauss magnetic fields when pellets are irradiated by lasers.

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