Filtration of biological suspension: membrane performance

2005 ◽  
Vol 5 (3-4) ◽  
pp. 227-232
Author(s):  
S. Delgado ◽  
F. Díaz ◽  
R. Villarroel ◽  
M.D. García ◽  
L. Vera ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Wastewater Reuse ◽  
Process Efficiency ◽  
Government Regulations ◽  
Quality Requirements ◽  
Membrane Performance ◽  
Several Variables ◽  
Dead End ◽  
Appropriate Treatment ◽  
Treatment Technologies

Wastewater reuse provides a substantial non-conventional water resource, mainly for agriculture. However, it requires appropriate treatment technologies and previous evaluation so as to meet quality requirements imposed by government regulations and crop needs. Among all the technologies applied to wastewater treatment, membrane-based systems have gained increasing importance, although their main drawback is progressive membrane fouling, which affects process efficiency enormously. The present study analyses the filterability of some biological suspensions as well as the influence of several variables in membrane fouling. Classic dead–end filtration models are used in an attempt to better understand fouling mechanisms and develop methods to prevent or retard it.

MBR/RO/ozone processes for TFT-LCD industrial wastewater treatment and recycling

2005 ◽  
Vol 51 (6-7) ◽  
pp. 411-419
Author(s):  
T.K. Chen ◽  
C.H. Ni ◽  
Y.C. Chan ◽  
M.C. Lu
Keyword(s):  
Water Quality ◽  
Industrial Wastewater ◽  
Bubble Column ◽  
Wastewater Reuse ◽  
Experimental Period ◽  
Membrane Unit ◽  
Treated Water ◽  
Effluent Quality ◽  
Appropriate Treatment ◽  
Treatment Technologies

This research is mainly to explore the treatment capacity for TFT-LCD industrial wastewater recycling by the processes combined with membrane bioreactor (MBR), reverse osmosis (RO) and ozone(O3). The organic wastewater from the TFT-LCD industry was selected as the target. MBR, RO and ozone plants were established for evaluation. An MBR plant consisted of a 2-stage anoxic/aerobic bioreactor and an immersed UF membrane unit was employed. The effluent of MBR was conducted into the RO system then into the ozone system. The RO system consisted of a spiral membrane in the vessel. One bubble column, 75 cm high and diameter 5 cm, were used as the ozonation reactor. On the bottom of ozonation reactor is a porous diffuser for releasing gas, with an aperture of 100 μm (0.1 cm). Over the whole experimental period, the MBR process achieved a satisfactory organic removal. The COD could be removed with an average of over 98.5%. For the TOC item, the average removal efficiency was 97.4%. The stable effluent quality and satisfactory removal performance were ensured by the efficient interception performance of an immersed UF membrane device incorporated with the biological reactor. Moreover, the MBR effluent did not contain any suspended solids and the SDI value was under 3. After the treatment of RO, excellent water quality was found. The water quality of permeate was under 5 mg/l, 2 mg/l and 50 μs/cm for COD, TOC and conductivity respectively. The treated water can be recycled and reused for the cooling tower make-up water or other purposes. After the treatment of ozone, the treated water quality was under 5 mg/l and 0.852 mg/l for COD and TOC respectively. The test results of MBR, MBR/RO and MBR/RO/ozone processes were compared as possible appropriate treatment technologies applied in TFT-LCD industrial wastewater reuse and recycling.

scholarly journals Effect of Ultrafiltration of Milk Prior to Fermentation on Mass Balance and Process Efficiency in Greek-Style Yogurt Manufacture

Foods ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 144 ◽  
Author(s):  
Adriana Paredes Valencia ◽  
Alain Doyen ◽  
Scott Benoit ◽  
Manuele Margni ◽  
Yves Pouliot
Keyword(s):  
Energy Consumption ◽  
Membrane Fouling ◽  
Skim Milk ◽  
Solid Content ◽  
Reduction Factor ◽  
Process Efficiency ◽  
Total Flux ◽  
Whey Permeate ◽  
Membrane Performance ◽  
Flux Decline

Ultrafiltration (UF) can be used to concentrate yogurt to produce Greek-style yogurt (GSY) (UF-YOG), but this generates acid whey permeate, which is an environmental issue. However, when UF is applied before fermentation (UF-MILK), a nonacidified whey permeate is generated. For this study, two model GSYs (UF-YOG and UF-MILK) were produced to compare the composition, UF performance, and energy consumption of the two processes. For UF-MILK, skim milk was ultrafiltered with a 30 kDa spiral-wound UF membrane to achieve a 3× volume reduction factor (VRF). The retentate was fermented to a pH of 4.5. The UF-YOG process was the same except that regular yogurt was ultrafiltered. Both GSYs had similar protein (~10%) and solid content (~17%). As expected, lactic acid/lactate was not detected in UF-MILK permeate, while 7.3 g/kg was recovered from the UF-YOG permeate. Permeation flux values (11.6 to 13.3 L m−2 h−1) and total flux decline (47% to 50%) were constant during UF-MILK, whereas drastic decreases in these two membrane performance indicators (average flux: 38.5 to 10.9 L m−2 h−1; total flux decline: 2% to 38%) were calculated for UF-YOG. Moreover, for UF-YOG, UF membrane performance never recovered, even when drastic and repeated cleaning steps were applied. Energy consumption was 1.6 kWh/kg GSY and remained constant for UF-MILK, whereas it increased from 0.6 to 1.5 kWh/kg GSY for UF-YOG. Our results show that, although the composition of GSYs was similar for both processes, the UF step of yogurt concentration affected process efficiency due to drastic and permanent membrane fouling.

scholarly journals Optimization of Air Backwash Frequency during the Ultrafiltration of Seawater

Membranes ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 78
Author(s):  
Clemence Cordier ◽  
Tarik Eljaddi ◽  
Nadjim Ibouroihim ◽  
Christophe Stavrakakis ◽  
Patrick Sauvade ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Module ◽  
Industrial Scale ◽  
Membrane Performance ◽  
Operation Conditions ◽  
Dead End ◽  
Variation Versus ◽  
In Series ◽  
Seawater Quality

The main objective of this paper is to study the effect of new air backwash on dead-end ultrafiltration of seawater with a pilot at semi-industrial scale (20 m3/day). To control membrane fouling, two different backwashes were used to clean the membrane: classical backwash (CB) and new air backwash (AB) that consists of injecting air into the membrane module before a classical backwash. To evaluate the efficiency of AB and CB, a resistance in series model was used to calculate each resistance: membrane (Rm), reversible (Rrev) and irreversible (Rirr). The variation of the seawater quality was considered by integrating the turbidity variation versus time. The results indicate clearly that AB was more performant than CB and frequency of AB/CB cycles was important to control membrane fouling. In this study, frequencies of 1/5 and 1/3 appear more efficient than 1/7 and 1/9. In addition, the operation conditions (flux and time of filtration) had an important role in maintaining membrane performance—whatever the variation of the seawater quality.

Technological aspects of wastewater management in coastal tourist areas

1999 ◽  
Vol 39 (8) ◽  
pp. 177-184 ◽  
Author(s):  
Derin Orhon ◽  
Seval Sözen ◽  
Erdem Görgün ◽  
Emine Ubay Çokgör ◽  
Nazik Artan
Keyword(s):  
Technology Selection ◽  
Specific Reference ◽  
Wastewater Management ◽  
Residential Areas ◽  
Treatment Technology ◽  
Environmentally Sensitive Areas ◽  
Appropriate Treatment ◽  
Treatment Technologies ◽  
Impact On Treatment ◽  
New Applications

Coastal tourist areas should be classified as environmentally sensitive areas. Effective nutrient control should be implemented to safeguard the quality of receiving waters in these areas. In this context, the applicable discharge limitations are reviewed with specific reference to European directives and criteria developed for small coastal residential areas in Turkey are reported; wastewater characterization and its impact on treatment technology selection is reviewed; appropriate treatment technologies are evaluated in terms of selecting new applications and upgrading and retrofitting existing systems.

scholarly journals Potential Pitfalls in Membrane Fouling Evaluation: Merits of Data Representation as Resistance Instead of Flux Decline in Membrane Filtration

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 460
Author(s):  
Bastiaan Blankert ◽  
Bart Van der Bruggen ◽  
Amy E. Childress ◽  
Noreddine Ghaffour ◽  
Johannes S. Vrouwenvelder
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Data Representation ◽  
Strong Impact ◽  
Experimental Conditions ◽  
Permeable Membrane ◽  
Dead End ◽  
Flux Decline ◽  
The Difference ◽  
Filtration Flux

The manner in which membrane-fouling experiments are conducted and how fouling performance data are represented have a strong impact on both how the data are interpreted and on the conclusions that may be drawn. We provide a couple of examples to prove that it is possible to obtain misleading conclusions from commonly used representations of fouling data. Although the illustrative example revolves around dead-end ultrafiltration, the underlying principles are applicable to a wider range of membrane processes. When choosing the experimental conditions and how to represent fouling data, there are three main factors that should be considered: (I) the foulant mass is principally related to the filtered volume; (II) the filtration flux can exacerbate fouling effects (e.g., concentration polarization and cake compression); and (III) the practice of normalization, as in dividing by an initial value, disregards the difference in driving force and divides the fouling effect by different numbers. Thus, a bias may occur that favors the experimental condition with the lower filtration flux and the less-permeable membrane. It is recommended to: (I) avoid relative fouling performance indicators, such as relative flux decline (J/J0); (II) use resistance vs. specific volume; and (III) use flux-controlled experiments for fouling performance evaluation.

scholarly journals Microwave and Ultrasound Based Methods in Sludge Treatment: A Review

2021 ◽  
Vol 11 (15) ◽  
pp. 7067
Author(s):  
Zoltán Jákói ◽  
Balázs Lemmer ◽  
Cecilia Hodúr ◽  
Sándor Beszédes
Keyword(s):  
Wastewater Sludge ◽  
Process Efficiency ◽  
H2o2 Treatment ◽  
Treatment Conditions ◽  
Appropriate Treatment ◽  
Scientific Papers ◽  
Health Related ◽  
Scientific Results ◽  
Treatment Procedures ◽  
Anaerobic Digestibility

The amount of waste activated sludge (WAS) is increasing annually, and since it presents potential environmental and health-related risks, an appropriate treatment and stabilization process is needed. It has been shown in numerous studies in the past few decades that amongst the advanced treatment methods of sludge, microwave and ultrasound-based processes offer promising and effective alternatives. The main advantage of these physical methods is that they are energy-efficient, easy to implement and can be combined with other types of treatment procedures without major difficulties. In this review article we would like to present the recent scientific results of the microwave, ultrasound and combined (microwave-alkaline, microwave-H2O2, ultrasound-alkaline and ultrasound-H2O2) treatment of wastewater sludge, in terms of different process-efficiency indicators. Although the obtained results somewhat vary between the different scientific papers, it can be undoubtedly stated that both MW and US—either individually or in combination with chemical treatments—can enhance several aspects of sludge processing, like increasing the SCOD/TCOD rate, disintegration degree (DD), or the anaerobic digestibility (AD), but the extent of these increments clearly depends on the treatment conditions or parameters.

scholarly journals Membrane Fouling Controlled by Adjustment of Biological Treatment Parameters in Step-Aerating MBR

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 553
Author(s):  
Dimitra C. Banti ◽  
Manassis Mitrakas ◽  
Petros Samaras
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Municipal Wastewater ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Aeration Tank ◽  
Filamentous Bacteria ◽  
Membrane Performance ◽  
Low Concentrations ◽  
Fouling Reduction

A promising solution for membrane fouling reduction in membrane bioreactors (MBRs) could be the adjustment of operating parameters of the MBR, such as hydraulic retention time (HRT), food/microorganisms (F/M) loading and dissolved oxygen (DO) concentration, aiming to modify the sludge morphology to the direction of improvement of the membrane filtration. In this work, these parameters were investigated in a step-aerating pilot MBR that treated municipal wastewater, in order to control the filamentous population. When F/M loading in the first aeration tank (AT1) was ≤0.65 ± 0.2 g COD/g MLSS/d at 20 ± 3 °C, DO = 2.5 ± 0.1 mg/L and HRT = 1.6 h, the filamentous bacteria were controlled effectively at a moderate filament index of 1.5–3. The moderate population of filamentous bacteria improved the membrane performance, leading to low transmembrane pressure (TMP) at values ≤2 kPa for a great period, while at the control MBR the TMP gradually increased reaching 14 kPa. Soluble microbial products (SMP), were also maintained at low concentrations, contributing additionally to the reduction of ΤΜP. Finally, the step-aerating MBR process and the selected imposed operating conditions of HRT, F/M and DO improved the MBR performance in terms of fouling control, facilitating its future wider application.

The Role of Wastewater Reuse in Water Resources Management in Israel

1991 ◽  
Vol 23 (10-12) ◽  
pp. 2081-2089 ◽  
Author(s):  
G. Shelef
Keyword(s):  
Crop Rotation ◽  
Water Resources Management ◽  
Agricultural Sector ◽  
Wastewater Reuse ◽  
Total Water ◽  
Quality Requirements ◽  
Resources Management ◽  
Effluent Quality ◽  
Tel Aviv

Wastewater reuse is considered as a major vital water resource in Israel with an annual flow of 420 million m planned for the year 2010 constituting 19% of the total water supply and about one third of the overall water allocated to the agricultural sector. The trend is for less crop restriction and wider crop rotation and thus higher effluent quality requirements. The economical considerations are favourable even with the need for seasonal storage and extra treatment. A brief description of the major wastewater reuse schemes, i.e. the Dan Region (Greater Tel-Aviv) and Greater Haifa - Tishlovet Hakishon is also given.

scholarly journals Flow and fouling in a pleated membrane filter

2016 ◽  
Vol 795 ◽  
pp. 36-59 ◽  
Author(s):  
P. Sanaei ◽  
G. W. Richardson ◽  
T. Witelski ◽  
L. J. Cummings
Keyword(s):  
Membrane Fouling ◽  
Membrane Filter ◽  
Small Particles ◽  
Porous Support ◽  
Equal Area ◽  
Membrane Filters ◽  
Membrane Pores ◽  
Dead End ◽  
Large Particles ◽  
Membrane Geometry

Pleated membrane filters are widely used in many applications, and offer significantly better surface area to volume ratios than equal-area unpleated membrane filters. However, their filtration characteristics are markedly inferior to those of equivalent unpleated membrane filters in dead-end filtration. While several hypotheses have been advanced for this, one possibility is that the flow field induced by the pleating leads to spatially non-uniform fouling of the filter, which in turn degrades performance. In this paper we investigate this hypothesis by developing a simplified model for the flow and fouling within a pleated membrane filter. Our model accounts for the pleated membrane geometry (which affects the flow), for porous support layers surrounding the membrane, and for two membrane fouling mechanisms: (i) adsorption of very small particles within membrane pores; and (ii) blocking of entire pores by large particles. We use asymptotic techniques based on the small pleat aspect ratio to solve the model, and we compare solutions to those for the closest-equivalent unpleated filter.

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