Hydrodynamic characterization in dissolved air flotation (DAF) contact zone

1998 ◽  
Vol 38 (6) ◽  
pp. 245-252 ◽  
Author(s):  
Ayman R. Shawwa ◽  
Daniel W. Smith
Keyword(s):  
Contact Zone ◽  
Peclet Number ◽  
Contact Time ◽  
Loading Rate ◽  
Dispersion Model ◽  
Dissolved Air Flotation ◽  
Péclet Number ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Recycle Ratio

The mechanism of bubble-floc interaction in a DAF contact zone is poorly understood and is usually described by conceptual models. This mechanism is highly dependent on the hydrodynamic conditions within the contact zone, i.e. contact time and degree of mixing. A pulse stimulus-response test was used to characterize the contact zone degree of mixing, in terms of dimensionless Peclet Number, and the contact time, in terms of residence time distribution. The tracer tests were performed at different hydraulic loading rates and recycle ratios. The experimental results confirmed that the axial dispersion model can be used to estimate the degree of mixing inside the contact zone. The results showed that the Peclet Number increased as the hydraulic loading rate increased, for all experiments performed under the same recycle ratio. In addition, the degree of mixing slightly increased as the recycle ratio increased, for all experiments performed under the same hydraulic loading rate.

PEMANFAATAN TANAH VULKANIK DALAM SISTEM MULTIPLE SOIL LAYERING (MSL) TERHADAP PEMURNIAN AIR IRIGASI TERPOLUSI

Jurnal BiBieT ◽  
2017 ◽  
Vol 2 (2) ◽  
pp. 49
Author(s):  
Welly Herman ◽  
Darmawan Darmawan ◽  
Gusnidar Gusnidar
Keyword(s):  
Irrigation Water ◽  
Loading Rate ◽  
Quality Standard ◽  
High Ability ◽  
Volcanic Soil ◽  
Soil Mixture ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Soil Layering ◽  
Mesh Sieve

<p><em>The research aimed to make Volcanic soil of Multiple Soil Layering (MSL) with different Hydraulic Loading Rate (HLR) on the purification of polluted irrigation water and to determine the appropriate HLR against purification of polluted irrigation water. The research used an MSL system of the same Soil Mixture Block (SMB) size from a study done by </em><em>(Chen et al., 2007)</em><em> arranged in an Acrylic box measuring 50 cm x 10 cm x 60 cm (PxLxT). Making SMB is done by mixing volcanic soil, sawdust, iron, charcoal that has been mashed by 50 mesh sieve, with a combination of 7: 1: 1: 1. The MSL system is supplied with irrigation water taken from the Gunuang Nago irrigation and Pasar Baru area, Cupak Tangah village, Pauh IX sub-district, Padang continuously with different HLR of 250 L/m<sup>2</sup>/day,     500 L/m<sup>2</sup>/ day and 1000 L/m<sup>2</sup>/day. From the result of this research, it is found that MSL system can decrease pollutant content in polluted irrigation water until the concentration below the water quality standard based on PP. 82 of 2001 and MSL system with HLR 250 L/m<sup>2</sup>/day have high ability in purifying BOD and COD and HLR 1000 L/m<sup>2</sup>/day has a high ability in purifying NH<sub>4</sub><sup>+</sup>, NO<sub>2</sub><sup>-</sup> and NO<sub>3</sub><sup>-</sup> on polluted irrigation water.</em></p><p class="jbd-alamat"> </p><p class="jbd-alamat">Tujuan penelitian ini adalah untuk menentukan pengaruh tanah vulkanik dalam sistem <em>Multiple Soil Layering</em> (MSL) dengan <em>Hydraulic Loading Rate</em> (HLR) yang berbeda terhadap pemurnian air irigasi terpolusi. Penelitian  menggunakan sistem MSL dengan ukuran <em>Soil Mixture Block</em> (SMB) yang sama dari penelitian yang telah dilakukan (Chen, Sato, Wakatsuki, &amp; Masunaga, 2007)yang disusun di dalam kotak Acrylic berukuran 50 cm x 10 cm x 60 cm (PxLxT).  <em>Soil Mixture Block</em> terdiri dari tanah vulkanik, serbuk gergaji, besi, arang yang telah dihaluskan oleh ayakan 50 mesh, dengan perbandingan kombinasi 7:1:1:1.  Sistem MSL dialirkan air irigasi yang diambil dari irigasi Gunuang Nago dan Kawasan Pasar Baru, Kelurahan Cupak Tangah, Kecamatan Pauh IX, Padang secara terus menerus dengan HLR yang berbeda yaitu 250 L/m<sup>2</sup>/hari,  500 L/m<sup>2</sup>/hari dan 1000 L/m<sup>2</sup>/hari. Dari hasil penelitian diperoleh bahwa sistem MSL mampu menurunkan kandungan zat pencemar pada air irigasi terpolusi  mencapai kosentrasi di bawah baku mutu air berdasarkan PP No. 82 tahun 2001 dengan HLR 250 L/m<sup>2</sup>/hari mempunyai kemampuan yang tinggi dalam memurnikan kadar pencemar BOD dan COD sedangkan HLR 1000 L/m2/hari mempunyai kemampuan yang tinggi dalam memurnikan kadar pencemar NH<sub>4</sub><sup>+</sup>, NO<sub>2</sub><sup>-</sup> dan NO<sub>3</sub><sup>-</sup> pada air irigasi terpolusi.</p>

Aeration characteristics of a rectangular stepped cascade system

2010 ◽  
Vol 61 (2) ◽  
pp. 415-420 ◽  
Author(s):  
Sanjib Moulick ◽  
Naresh V. Tambada ◽  
Basant K. Singh ◽  
B. C. Mal
Keyword(s):  
Surface Area ◽  
Loading Rate ◽  
Experimental Results ◽  
Step Height ◽  
Optimum Number ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Aeration Efficiency ◽  
Stepped Cascade ◽  
Independent Parameters

Aeration experiments, maintaining nappe flow conditions, were carried out on a rectangular stepped cascade of total height 3.0 m to determine the total number of steps, slope of the entire cascade and hydraulic loading rate at which maximum overall aeration efficiency occurs, keeping the surface area of individual steps constant. Based on dimensional analysis, the overall aeration efficiency at standard conditions (E20) was expressed as a function of square of total number of steps (N2) and dimensionless discharge (dc/h), where dc and h represent critical depth in a rectangular prismatic channel and individual step height respectively. An empirical equation with E20 as the response and N2 and dc/h as the independent parameters was developed based on the experimental results subject to 36 ≤ N2 ≤ 196 and 0.009 ≤ dc/h ≤ 0.144. The experimental results showed that the overall aeration efficiency (E20) for a particular step height of stepped cascade increases with increase in dc/h up to a certain value and then decreases. This may be due to at higher dc/h, i.e., at higher hydraulic loading rate, the flow approaches the transition zone and thereby aeration efficiency decreases. E20 was also found to increase with number of steps at any hydraulic loading rate, because of the increased surface area of fall. The optimum number of steps, slope of the entire stepped cascade and hydraulic loading rate were found to be 14, 0.351 and 0.009 m2/s respectively producing the maximum value of overall aeration efficiency of 0.90.

Impact of hydraulic loading rate and media type on removal of bulk organic matter and nitrogen from primary effluent in a laboratory-scale soil aquifer treatment system

2013 ◽  
Vol 68 (1) ◽  
pp. 217-226 ◽  
Author(s):  
Chol D. T. Abel ◽  
Saroj K. Sharma ◽  
Ervin Buçpapaj ◽  
Maria D. Kennedy
Keyword(s):  
Organic Matter ◽  
Loading Rate ◽  
Ammonium Nitrogen ◽  
Silica Sand ◽  
Soil Aquifer Treatment ◽  
Nitrogen Reduction ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Media Type ◽  
Bulk Organic Matter

The effect of hydraulic loading rate (HLR) and media type on the removal of bulk organic matter and nitrogen from primary effluent during soil aquifer treatment was investigated by conducting laboratory-scale soil column studies. Two soil columns packed with silica sand were operated at HLRs of 0.625 and 1.25 m/d, while a third column was packed with dune filtering material and operated at HLR of 1.25 m/d. Bulk organic matter was effectively removed by 47.5 ± 1.2% and 45.1 ± 1.2% in silica sand columns operated at 0.625 and 1.25 m/d, respectively and 57.3 ± 7.6% in dune filtering material column operated at 1.25 m/d. Ammonium-nitrogen reduction of 74.5 ± 18.0% was achieved at 0.625 m/d compared to 39.1 ± 4.3% at 1.25 m/d in silica sand columns, whereas 49.2 ± 5.2% ammonium-nitrogen reduction was attained at 1.25 m/d in the dune filtering material column. Ammonium-nitrogen reduction in the first 3 m was assumed to be dominated by nitrification process evidenced by corresponding increase in nitrate. Part of the ammonium-nitrogen was adsorbed onto the media, which was observed at higher rates between 3 and 5 m in silica sand column operated at HLR of 0.625 m/d and dune filtering material column operated at 1.25 m/d compared to 1.25 m/d silica.

Effect of aeration and hydraulic loading rate on nitrogen removal by subsurface infiltration systems

2019 ◽  
Vol 91 (5) ◽  
pp. 399-406
Author(s):  
Fanping Zheng ◽  
Linli Huang ◽  
Jing Pan ◽  
Shiyue Qi ◽  
Chaoquan Tan ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Loading Rate ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading

Influence of Hydraulic Loading Rate on Horizontal Zeolite Wetland Effluent Quality

2012 ◽  
Vol 573-574 ◽  
pp. 659-662
Author(s):  
Hao Wang
Keyword(s):  
Wastewater Treatment ◽  
Loading Rate ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Secondary Effluent ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Hydraulic Loading Rate ◽  
Effluent Quality ◽  
Hydraulic Loading

In Tangshan area, the secondary effluent of wastewater treatment plants was used for this study. Horizontal zeolite wetland was carried out treating it. Hydraulic loading rate was the parameters for analyzing the nitrogen and phosphorus removal efficiency of pollutants from the secondary effluent of wastewater treatment plant. Zeolite constructed wetlands showed different behaviors for nitrogen and phosphorus removals.Under the optimum hydraulic loading rate, the primary pollutions were removed to a large extent.

Effects of Hydraulic Loading Rate on Nutrient Removal in Multi-Stage Constructed Wetland

2013 ◽  
Vol 864-867 ◽  
pp. 1498-1502
Author(s):  
Qing Feng Chen ◽  
Wen Guo Dong ◽  
Jun Jian Ma ◽  
Qing Li ◽  
Xin Guo Gao ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Loading Rate ◽  
Optimal Parameter ◽  
Removal Rate ◽  
Operational Parameter ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Multi Stage ◽  
Operation Period ◽  
D 12

Hydraulic loading rate (HLR) is an important operational parameter for constructed wetland to purify wastewater. In this paper, it is the main objective to select the optimal parameter of HLR. During the four HLRs (i.e., 6 cm/d, 12 cm/d, 24 cm/d and 48 cm/d) operation period, six days were used as one stage. The experimental results showed that the best average removal rates of CODcr (59.7%) and NH3-N (89.4%) were at the HLR of 6 cm/d. In the meantime, the best average removal rate of total phosphorus (TP, 50.0%) was at the HLR of 24 cm/d. According to the low influent TP concentration, it is suggested that the HLR of 6 cm/d should be used in the multi-stage constructed wetland.

scholarly journals Evaluation method of single blow experiment for the determination of heat transfer coefficient and dispersive Peclet number

2015 ◽  
Vol 36 (4) ◽  
pp. 3-24 ◽  
Author(s):  
Wilfried Roetzel ◽  
Chakkrit Na Ranong
Keyword(s):  
Heat Exchangers ◽  
Peclet Number ◽  
Numerical Evaluation ◽  
Evaluation Method ◽  
Dispersion Model ◽  
Tracer Experiment ◽  
Effective Number ◽  
Péclet Number ◽  
Modified Method

Abstract An evaluation method is developed for single blow experiments with liquids on heat exchangers. The method is based on the unity Mach number dispersion model. The evaluation of one experiment yields merely one equation for the two unknowns, the number of transfer units and the dispersive Peclet number. Calculations on an example confirm that one single blow test alone cannot provide reliable values of the unknowns. A second test with a liquid of differing heat capacity is required, or a tracer experiment for the measurement of the Peclet number. A modified method is developed for gases. One experiment yields the effective number of transfer units and approximate values of the two unknowns. The numerical evaluation of calculated experiments demonstrates the applicability of the evaluation methods.

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