Influence of diazonium‐induced surface grafting on PES NF membrane fouling reduction in algal‐rich water treatment

A rapid small-scale evaluation of ultrafiltration (UF) performance with and without physical–chemical pre-treatment was performed to up-grade the conventional treatment used for drinking water production in Alcantarilha's water treatment works, Algarve, Portugal. Direct UF and pre-ozonation/coagulation/flocculation/sedimentation/UF (O/C/F/S/UF) were evaluated using polysulphone membranes of different apparent molecular weight cut-off (MWCO) (15–47 kDa). The results indicated that (i) UF is an effective barrier against microorganisms, including virus larger than 80 nm; (ii) for surface waters with low to moderate SUVA values, direct UF performance is equivalent or better than the conventional treatment in terms of residual turbidity, while UV254 nm and TOC residuals require the use of O/C/F/S/UF; (iii) the permeate quality improves with the membrane apparent MWCO decrease, especially for the direct UF, although the conventional treatment performance is never reached using UF; (iv) membrane fouling and adsorption phenomena are more severe in direct UF than in O/C/F/S/UF sequence (pre-ozonation decreases the membrane foulants by decreasing their hydrophobicity) and these phenomena increase with the membrane hydraulic permeability and, particularly, with the membrane apparent MWCO.

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Effect of Pre-Oxidation on Coagulation/Ceramic Membrane Treatment of Yangtze River Water

Membranes ◽

10.3390/membranes11050369 ◽

2021 ◽

Vol 11 (5) ◽

pp. 369

Author(s):

Shengji Xia ◽

Xinran Zhang ◽

Yuanchen Zhao ◽

Fibor J. Tan ◽

Pan Li ◽

...

Keyword(s):

Water Treatment ◽

Membrane Fouling ◽

Membrane Filtration ◽

Ceramic Membrane ◽

Membrane Separation ◽

Membrane System ◽

Coagulation System ◽

Fouling Control ◽

Filtration System ◽

Membrane Treatment

The membrane separation process is being widely used in water treatment. It is very important to control membrane fouling in the process of water treatment. This study was conducted to evaluate the efficiency of a pre-oxidation-coagulation flat ceramic membrane filtration process using different oxidant types and dosages in water treatment and membrane fouling control. The results showed that under suitable concentration conditions, the effect on membrane fouling control of a NaClO pre-oxidation combined with a coagulation/ceramic membrane system was better than that of an O3 system. The oxidation process changed the structure of pollutants, reduced the pollution load and enhanced the coagulation process in a pre-oxidation-coagulation system as well. The influence of the oxidant on the filtration system was related to its oxidizability and other characteristics. NaClO and O3 performed more efficiently than KMnO4. NaClO was more conducive to the removal of DOC, and O3 was more conducive to the removal of UV254.

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

Membranes ◽

10.3390/membranes11080553 ◽

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.

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Coupling continuous sand filtration to ultrafiltration for drinking water treatment: Improved performance and membrane fouling control

Journal of Membrane Science ◽

10.1016/j.memsci.2018.09.034 ◽

2018 ◽

Vol 567 ◽

pp. 18-27 ◽

Cited By ~ 10

Author(s):

Yuanqing Guo ◽

Langming Bai ◽

Xiaobin Tang ◽

Qiaojin Huang ◽

Binghan Xie ◽

...

Keyword(s):

Drinking Water ◽

Water Treatment ◽

Membrane Fouling ◽

Drinking Water Treatment ◽

Sand Filtration ◽

Fouling Control ◽

Improved Performance

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Optimal Water Backwashing Condition in Combined Water Treatment of Alumina Microfiltration and PP Beads

Membranes ◽

10.3390/membranes12010092 ◽

2022 ◽

Vol 12 (1) ◽

pp. 92

Author(s):

Hyungmin Cho ◽

Gihoon Yoon ◽

Minjae Kim ◽

Jin Yong Park

Keyword(s):

Water Treatment ◽

Membrane Fouling ◽

Treatment Process ◽

Membrane Separation ◽

Combined Process ◽

Water Treatment Process ◽

A Minor ◽

Membrane Shape ◽

Tubular Membranes ◽

Total Membrane

Membrane fouling is a dominant limit of the membrane separation process. In this research, the optimal water backwashing to solve the membrane fouling problem was investigated in the combined water treatment process of alumina MF and pure polypropylene (PP) beads. Additionally, the influence of membrane shape (tubular or seven channel) was examined, depending on the water backwashing period. The optimal backwashing time (BT) could be 20 s in the combined water treatment process, because of the highest total treated volume (VT) in our BT 6–30 s conditions. The optimal backwashing period (BP) could be 6 min, because of the minimum membrane fouling and the maximum VT in the combined process of tubular alumina MF and PP beads. The resistance of reversible membrane fouling (Rrf) showed a major resistance of total membrane fouling, and that of irreversible membrane fouling (Rif) was a minor one, in the combined process using tubular or seven channel MF. The Rif showed a decreasing trend obviously, as decreasing BT from NBW to 2 min for seven channel MF. It means that the more frequent water backwashing could be more effective to control the membrane fouling, especially irreversible fouling, for seven channel membranes than tubular membranes.

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Effects of magnetization on Fe(iii) species in magnetically enhanced coagulation ultrafiltration processes

RSC Advances ◽

10.1039/c6ra20026e ◽

2016 ◽

Vol 6 (87) ◽

pp. 84397-84405 ◽

Cited By ~ 1

Author(s):

Jie Wang ◽

Sasa Yang ◽

Hui Jia ◽

Hongwei Zhang

Keyword(s):

Water Treatment ◽

Membrane Fouling ◽

Polluted Water ◽

Enhanced Coagulation ◽

Floc Properties

The effects of magnetization on floc properties and membrane fouling in magnetically enhanced coagulation ultrafiltration (MEC-UF) processes for micro-polluted water treatment were investigated in this study.

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