Pretreatment chemistry for dual media filtration: model simulations and experimental studies

2006 ◽  
Vol 53 (7) ◽  
pp. 167-175 ◽  
Author(s):  
J.Y. Shin ◽  
C.R. O'Melia
Keyword(s):  
Rapid Development ◽  
Experimental Studies ◽  
Raw Water ◽  
Small Particles ◽  
Model Simulations ◽  
Direct Filtration ◽  
Filter Performance ◽  
Suboptimal Dose ◽  
Particle Counts ◽  
Filtration Model

Laboratory dual media filtration experiments were conducted (a) in direct filtration mode using model raw water moderate in turbidity and low in DOC, and (b) in conventional filtration mode treating water moderate in turbidity and high in DOC. Model simulations of filter performance for the removal of particles provided hypotheses for the experimental studies of dual media filtration. An increase in alum dose in direct filtration mode, while improving filter performance, also showed some disadvantages, including rapid development of head loss. Suboptimal dose in direct filtration significantly impaired the filter performance. In conventional mode, the effect of alum dose on the filter performance, while obvious, was not as dramatic as in direct filtration. Ripening indicated by particle counts occurred earlier than by turbidity and breakthrough of particle counts started earlier than breakthrough of turbidity, suggesting that turbidity can be used as a more conservative monitor of filter performance during the ripening period to minimise the risk of passage of small particles, while particle counts can be considered a more sensitive indicator of deteriorating filter performance during the breakthrough period. The lower sand layer served as a multiple barrier for particles when the performance of the anthracite layer was not effective.

Removal of particles using dual media filtration: modeling and experimental studies

2001 ◽  
Vol 1 (4) ◽  
pp. 73-79 ◽  
Author(s):  
C.R. O'Melia ◽  
J.Y. Shin
Keyword(s):  
Mathematical Modeling ◽  
Filtration Rate ◽  
Experimental Studies ◽  
Head Loss ◽  
Particle Removal ◽  
Chemical Pretreatment ◽  
Column Studies ◽  
Filter Performance ◽  
Particle Counts ◽  
Filtration Modeling

The performance of packed beds using dual media for removing particles is examined using both predictive mathematical modeling and experimental column studies. Models for the effectiveness of clean filter beds were used to simulate the effects of chemical pretreatment and filtration rate on particle removal at the onset of filtration runs. Experimental studies were conducted over complete filtration runs and were evaluated using measurements of head loss development and removals of turbidity, UV254 absorbance, and particles. The results indicate that dual media beds have significant advantages over monomedia beds during both filter ripening and filter breakthrough; they are particularly helpful at high filtration rates and during periods of inadequate chemical pretreatment. Finally, particle counts provide an earlier indicator of deteriorating filter performance than turbidity measurements at the end of a run.

Évolution du nombre de particules dans l'eau filtrée d'une filière de filtration directe utilisant le polychlorure d'aluminium

1999 ◽  
Vol 26 (6) ◽  
pp. 771-781
Author(s):  
Souleymane Ndiongue ◽  
Raymond Desjardins ◽  
Michèle Prévost ◽  
Chantal Morissette
Keyword(s):  
The Other ◽  
Raw Water ◽  
Polyaluminum Chloride ◽  
Direct Filtration ◽  
Total Particle ◽  
High Turbidity ◽  
Particle Counts ◽  
St Lawrence River ◽  
Do So

This text presents and discusses the performances of direct filtration evaluated by means of particle counts and turbidity of raw water in periods of low and high turbidity. It also deals with the relationships between the removals of particles measuring from 2 to 150 µm (total counts) and those of particles in the other size ranges, which vary from 2 to 5 and from 5 to 15 µm. The tests were carried out on a pilot plant (20 m3/h) that treats waters from the St. Lawrence River (Canada) using the polyaluminum chloride (PACl) coagulation method followed by rapid filtration at 10 m/h. The results show that when the turbidity of the raw water is low, it is not always possible to predict a filter breakthrough based on the turbidity of its effluent, whereas it is possible to do so by observing the evolution of the particle counts. There exist good correlations between the removals of the total particle counts (2-150 µm) and those of the counts of particles in the other size ranges (2-5 and 5-15 µm). Furthermore, the evolution of all these ranges of particle size reveals the same tendencies with respect to the quality of the filtered water.Key words: direct filtration, in-line filtration, filtration, particle counts, turbidity, polyaluminum chloride.

Experimental study on non-woven filamentous fibre micro-filter with high filtration speed

2015 ◽  
Vol 71 (9) ◽  
pp. 1414-1422 ◽  
Author(s):  
Siping Niu ◽  
Kisoo Park ◽  
Heidi B. Guerra ◽  
Youngchul Kim
Keyword(s):  
Filtration Rate ◽  
Experimental Studies ◽  
Head Loss ◽  
High Rate ◽  
High Porosity ◽  
Raw Water ◽  
Water Turbidity ◽  
Filter Performance ◽  
Filter Process ◽  
Filter Aid

A laboratory study was undertaken to pursue the filter performance of a micro-filter module employing highly porous fibre media under a high filtration rate (≥1,500 m/day), faster than that of any conventional filter process. The effects of filtration rate, head loss, raw water turbidity, and filter aid chemicals on filter performance were analysed. In spite of the extremely high filtration rate, the filter achieved an attractive efficiency, reducing the raw water turbidity by over 80%. As with other filter systems, the filter aid used ((polyaluminium chloride (PAC)) greatly affected the performance of this particular fibre filter. Long-term repetitive runs were additionally carried out to confirm the reproducibility of the filter performance. Also, a comparison was carried out with other high-rate filter systems which are either being tested for use in experimental studies, or are already commercially available. This study reveals that the filter performance under a high filtration speed is still attractive especially as PAC is used. Due to the high porosity of the fibre, the filter had small head loss even though the filtration rate was high. These results ascertain that it is possible to operate the filters with high filtration rate achieving reliable treatment performance.

Pre-Ozonation-Coagulant Interactions in Direct Filtration

2010 ◽  
Vol 45 (3) ◽  
pp. 317-326 ◽  
Author(s):  
Murat Eyvaz ◽  
Hatice Deniz ◽  
Tuğrul S. Aktaş ◽  
Ebubekir Yüksel ◽  
Ahmet M. Saatçi
Keyword(s):  
Ferric Chloride ◽  
Aluminum Sulfate ◽  
Pilot Scale ◽  
The Other ◽  
Design Parameters ◽  
Dimensionless Number ◽  
Raw Water ◽  
Direct Filtration ◽  
Effluent Quality ◽  
Sulfate Application

Abstract Pre-ozonation–coagulant interactions effects in relation to the coagulant type and dosage in direct filtration of surface waters were investigated. The performance of the process was evaluated by monitoring the effluent quality and head loss development through the filter bed. Two identical pilot scale filter columns filtering the same raw water were operated in parallel. The raw water was brought from Ömerli Reservoir in Istanbul. Before filtering, the raw water flow was split into two equal flows. One of the streams was pre-ozonated and the other was aerated using contact chambers with equal volumes equipped with same number and type of diffusers. In coagulation experiments, one of the filters was operated using aluminum sulfate as a coagulant while the other one was run with ferric chloride. For similar filter run times, the effluent quality was always better with pre-ozonation compared to aeration. It was also observed that, aluminum sulfate application gave more favorable results for both particle and turbidity removal compared to ferric chloride. Ives’ filterability index which incorporates the important filtration design parameters such as: effluent quality, the headloss and the velocity of filtration into a dimensionless number was used for the comparison of the experimental results.

Regulation of myocardial substrate metabolism during increased energy expenditure: insights from computational studies

2006 ◽  
Vol 291 (3) ◽  
pp. H1036-H1046 ◽  
Author(s):  
Lufang Zhou ◽  
Marco E. Cabrera ◽  
Isidore C. Okere ◽  
Naveen Sharma ◽  
William C. Stanley
Keyword(s):  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Myocardial Oxygen Consumption ◽  
Experimental Studies ◽  
Cardiac Metabolism ◽  
Substrate Selection ◽  
Abrupt Increase ◽  
Model Simulations ◽  
Atp Production ◽  
Parallel Activation

In response to exercise, the heart increases its metabolic rate severalfold while maintaining energy species (e.g., ATP, ADP, and Pi) concentrations constant; however, the mechanisms that regulate this response are unclear. Limited experimental studies show that the classic regulatory species NADH and NAD+ are also maintained nearly constant with increased cardiac power generation, but current measurements lump the cytosol and mitochondria and do not provide dynamic information during the early phase of the transition from low to high work states. In the present study, we modified our previously published computational model of cardiac metabolism by incorporating parallel activation of ATP hydrolysis, glycolysis, mitochondrial dehydrogenases, the electron transport chain, and oxidative phosphorylation, and simulated the metabolic responses of the heart to an abrupt increase in energy expenditure. Model simulations showed that myocardial oxygen consumption, pyruvate oxidation, fatty acids oxidation, and ATP generation were all increased with increased energy expenditure, whereas ATP and ADP remained constant. Both cytosolic and mitochondrial NADH/NAD+ increased during the first minutes (by 40% and 20%, respectively) and returned to the resting values by 10–15 min. Furthermore, model simulations showed that an altered substrate selection, induced by either elevated arterial lactate or diabetic conditions, affected cytosolic NADH/NAD+ but had minimal effects on the mitochondrial NADH/NAD+, myocardial oxygen consumption, or ATP production. In conclusion, these results support the concept of parallel activation of metabolic processes generating reducing equivalents during an abrupt increase in cardiac energy expenditure and suggest there is a transient increase in the mitochondrial NADH/NAD+ ratio that is independent of substrate supply.

Direct filtration with preozonation for small water treatment systems

2004 ◽  
Vol 48 (11-12) ◽  
pp. 473-479 ◽  
Author(s):  
E. Yüksel ◽  
Ö Akgiray ◽  
E. Soyer
Keyword(s):  
Treatment Method ◽  
Silica Sand ◽  
Particle Removal ◽  
Raw Water ◽  
Particle Count ◽  
Direct Filtration ◽  
Small Water ◽  
On Line ◽  
Very High ◽  
Different Water Sources

The possibility of applying preozonation followed by direct filtration without the use of a coagulant is investigated. Filtration experiments have been carried out using four different water sources within Istanbul. A 1 m deep bed of 0.8-1.2 mm silica sand was used as the filter medium. The filter was operated at a rate of 11.5 m/hr. Raw water turbidities ranged from 2.3 NTU to 10.0 NTU. Effluent turbidity and particle count values were monitored using an on-line turbidimeter and an on-line particle counter. With all the waters studied in this work, preozonation improved particle removal in direct filtration. With three of the mentioned waters, it was possible to achieve turbidity values below 1.0 NTU without a coagulant by applying ozone at a rate between 1.7-1.8 mg/L. It was not possible to reduce the turbidity of one of the waters to below 2.7 NTU even with very high ozone dosages. The need for pilot testing before deciding if this treatment method is applicable to a given water is underlined.

Experimental Studies on Enhanced Coagulation of Tail Water

2013 ◽  
Vol 295-298 ◽  
pp. 1478-1481
Author(s):  
Feng Xun Tan ◽  
Jiu Mei Wang ◽  
Dao Ji Wu
Keyword(s):  
Ferric Chloride ◽  
Removal Rate ◽  
Reclaimed Water ◽  
Experimental Studies ◽  
Ammonia Nitrogen ◽  
Raw Water ◽  
Nitrogen And Phosphorus ◽  
Enhanced Coagulation ◽  
Tail Water ◽  
Water Eutrophication

Traditional wastewater treatment methods can no longer remove effectively nitrogen and phosphorus that are the direct murderers of water eutrophication hazard. Enhanced coagulation method was adopted to improve the treatment effect by dosing suitable coagulants and coagulant aids. The raw water was from the reclaimed water in a University. TP and ammonia nitrogen removal of the water had been researched through an enhanced coagulation process with dosing ferric chloride, aluminum sulfate, polymeric ferric chloride, and poly-aluminum chloride (PAC) in this study. The coagulants effects were estimated by determining the removal rate of ammonia nitrogen, TP, COD and turbidity. When dosing the raw water with 80 mg/L PAC, the removal rates of ammonia nitrogen, TP, COD and turbidity are respectively 6.12%, 67.79%, 26.21%, 85.41%. The experimental results can be used as a reference of water treatment in the reclaimed water station.

Research on Blue-Algae Removal from Eutrophication Water by Modified Clay

2010 ◽  
Vol 150-151 ◽  
pp. 178-182
Author(s):  
Li Ping Wang ◽  
Lei Lu ◽  
Nai Yuan Gao ◽  
Xia Xu ◽  
Yong Yin Zhang ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Rapid Development ◽  
Source Water ◽  
Raw Water ◽  
Chl A ◽  
Modified Clay ◽  
Algae Removal ◽  
Lake Type

In recent years, the problem of contaminated source water is increasingly outstanding with the rapid development of industry，agriculture and population. Especially, the eutrophication of river and lake is severer. The modified clay was studied to remove algae in lake type raw water in which average concentrations of turbidity, TN, TP and Chl-a were 33NTU, 4.002 mg/L, 0.263mg/L and 29.02 mg/m3. The results showed that the average removal efficiency of turbidity, TN, TP and Chl-a were 88.53%、26.61%、87.45% and 87.97% respectively when the dosage of modified clay was 0.8 g/L.

Pretreatment processes for membrane filtration of raw water containing manganese

2001 ◽  
Vol 1 (5-6) ◽  
pp. 341-348 ◽  
Author(s):  
S. Takizawa ◽  
L. Fu ◽  
N. Pradhan ◽  
T. Ike ◽  
M. Ohtaki ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Manganese Concentration ◽  
Fluidised Bed ◽  
Raw Water ◽  
Biological Pretreatment ◽  
Manganese Removal ◽  
Time Required

Experimental studies on chemical and biological pretreatments in membrane filtration processes were carried out to removal manganese contained in raw water and to prevent membrane fouling due to manganese. Two types of the pretreatment reactors, i.e. the fluidised-bed and fixed-bed configurations, were compared in the biological pretreatment experiments. New synthetic media (tubular polypropylene, I.D. 3 mm, O.D. 4 mm, length 5 mm) were used in all three experiments as a manganese-oxidising catalyst. The chemical pretreatment using sodium hypochlorite was effective in manganese removal and controlling membrane fouling; more than 0.8 mg-Cl2/L of chlorine dose was necessary to bring the manganese concentration from 0.4 mg/L in raw water to less than 0.05 mg/L. The biological pretreatment for manganese removal required a long start-up period of more than 40 days. The fixed-bed biological pretreatment was superior in manganese removal and in control of membrane fouling to the fluidised-bed biological pretreatment, which showed wash-out of the attached bacteria resulting in membrane fouling. The linear velocity and the empty-bed retention time required for the treatment of 0.14 mg-Mn/L in the fixed-bed biological pretreatment was 206 m/d and 8.0 minutes, respectively.

Simulations of atmospheric CO2 and δ13C-CO2 compared to real-time observations at the high altitude station Jungfraujoch

2020 ◽  
Author(s):  
Simone M. Pieber ◽  
Béla Tuzson ◽  
Stephan Henne ◽  
Ute Karstens ◽  
Dominik Brunner ◽  
...  
Keyword(s):  
Stable Isotope ◽  
High Altitude ◽  
Time Resolution ◽  
Experimental Studies ◽  
Isotope Ratios ◽  
Particle Dispersion ◽  
Stable Isotope Ratios ◽  
Research Station ◽  
Data Set ◽  
Model Simulations

<p>Evaluating atmospheric transport simulations against observations helps refining bottom-up estimates of greenhouse gas fluxes and identifying gaps in our understanding of regional and category-specific contributions to atmospheric mole fractions. This insight is critical in the efforts to mitigate anthropogenic environmental impact. Beside total mole fractions, stable isotope ratios provide further constraints on source-sink processes [1-3].</p><p>Here, we present two receptor-oriented model simulations for carbon dioxide (CO<sub>2</sub>) mole fraction and δ<sup>13</sup>C-CO<sub>2</sub> stable isotope ratios for a nine year period (2009-2017) at the High Altitude Research Station Jungfraujoch (Switzerland, 3580 m asl). The model simulations of CO<sub>2</sub> were performed on a 3-hourly time-resolution with two backward Lagrangian particle dispersion models driven by two different numerical weather forecast fields: FLEXPART-COSMO and STILT-ECMWF. Anthropogenic CO<sub>2</sub> fluxes were based on the EDGAR v4.3 emissions inventory aggregated into 14 source categories representing fossil and biogenic fuel uses as well as emissions from cement production. Biospheric CO<sub>2</sub> fluxes representing the photosynthetic uptake and respiration of 8 plant functional types were based on the Vegetation Photosynthesis and Respiration Model (VPRM). The simulated CO<sub>2</sub> emissions per source and sink category were weighted with category-specific δ<sup>13</sup>C-CO<sub>2</sub> signatures from published experimental studies. Background CO<sub>2</sub> values at the boundaries of both model domains were taken from global model simulations and the corresponding δ<sup>13</sup>C-CO<sub>2</sub> values were constructed as suggested in Ref. [3]. We compare the simulations to a unique data set of continuous in-situ observations of CO<sub>2</sub> mole fractions and δ<sup>13</sup>C-CO<sub>2</sub> stable isotope ratios by quantum cascade laser absorption spectroscopy as described in previous work [1, 4-5], available for the whole nine year period at the site.</p><p>The simulated atmospheric CO<sub>2</sub> and δ<sup>13</sup>C-CO<sub>2</sub> time-series are in good agreement with the observations and capture the observed variability at the models' 3-hourly time-resolution. This allows for an in-depth evaluation of the contribution of different CO<sub>2</sub> emission sources and for an allocation of source regions when Jungfraujoch is influenced by air masses from the planetary boundary layer. In brief, the receptor-oriented model simulations suggest that anthropogenic CO<sub>2</sub> contributions are primarily of fossil origin (90%). Anthropogenic emissions contribute between 60% in February, and 20% in July/August, to the CO<sub>2</sub> enhancements observed at Jungfraujoch. The remaining fraction is due to biosphere respiration, which thus largely dominates emissions during the summer season. However, intense photosynthetic CO<sub>2</sub> uptake during June, July and August roughly outweighs CO<sub>2</sub> contributions from anthropogenic activities and biosphere respiration at JFJ.</p><p> </p><p> </p><p>REFERENCES</p><p>[1] Tuzson et al., 2011. ACP, 11, 1685</p><p>[2] Röckmann et al., 2016. ACP, 16, 10469</p><p>[3] Vardag et al., 2016. Biogeosciences, 13, 4237</p><p>[4] Tuzson et al., 2008. Appl. Phys. B, 92, 451</p><p>[5] Sturm et al., 2013. AMT 6, 1659</p>

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