scholarly journals Capillary Nanofiltration under Anoxic Conditions as Post-Treatment after Bank Filtration

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1599 ◽  
Author(s):  
Jeannette Jährig ◽  
Leo Vredenbregt ◽  
Daniel Wicke ◽  
Ulf Miehe ◽  
Alexander Sperlich
Keyword(s):  
Organic Carbon ◽  
Membrane Fouling ◽  
Pilot Scale ◽  
Bank Filtration ◽  
Organic Micropollutants ◽  
Current Water ◽  
Pre Treatment ◽  
Iron And Manganese ◽  
Good Retention

Bank filtration schemes for the production of drinking water are increasingly affected by constituents such as sulphate and organic micropollutants (OMP) in the source water. Within the European project AquaNES, the combination of bank filtration followed by capillary nanofiltration (capNF) is being demonstrated as a potential solution for these challenges at pilot scale. As the bank filtration process reliably reduces total organic carbon and dissolved organic carbon (DOC), biopolymers, algae and particles, membrane fouling is reduced resulting in long term operational stability of capNF systems. Iron and manganese fouling could be reduced with the possibility of anoxic operation of capNF. With the newly developed membrane module HF-TNF a good retention of sulphate (67–71%), selected micropollutants (e.g., EDTA: 84–92%) and hardness (41–55%) was achieved together with further removal of DOC (82–87%). Fouling and scaling could be handled with a good cleaning concept with acid and caustic. With the combination of bank filtration and capNF a possibility for treatment of anoxic well water without further pre-treatment was demonstrated and retention of selected current water pollutants was shown.

scholarly journals Impact of Chlorinated-Assisted Backwash and Air Backwash on Ultrafiltration Fouling Management for Urban Wastewater Tertiary Treatment

Membranes ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 733
Author(s):  
Jiaqi Yang ◽  
Mathias Monnot ◽  
Lionel Ercolei ◽  
Philippe Moulin
Keyword(s):  
Physicochemical Properties ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Pilot Scale ◽  
Urban Wastewater ◽  
Cleaning Efficiency ◽  
Filtration Performance ◽  
Potential Damage ◽  
Wastewater Tertiary Treatment

To improve membrane fouling management, the NaClO-assisted backwash has been developed to improve permeability maintenance and reduce the need for intensive chemical cleanings. This study is aimed to focus on the efficiency of NaClO-assisted backwash in real UF pilot scale and with periodic classic backwash (CB) and air backwash (AB). The impacts on hydraulic filtration performance, physicochemical properties of membrane material under different addition frequencies of NaClO, and the performance of chlorinated CB and AB will be discussed. In result, 10 mg Cl2 L−1 NaClO addition in backwash water is confirmed to greatly improve the overall filtration performance and backwash cleaning efficiency. One condition stands out from the other due to better control of irreversible fouling, less NaClO consumption in 10 years prediction, sustainable and adaptable filtration performance, and less potential damage on the physicochemical properties of the membrane. Additionally, it can be inferred from this experiment that frequent contact with NaClO induced some degradation on the PES-made UF membrane surface properties. To retain the best state of UF membrane on anti-fouling and qualified production, the optimized condition with more frequent NaClO contact was not suggested for long-term filtration.

Performance and membrane foulant in the pilot operation of a novel biofilm-membrane reactor

2002 ◽  
Vol 2 (2) ◽  
pp. 177-183
Author(s):  
K. Kimura ◽  
Y. Watanabe
Keyword(s):  
Membrane Fouling ◽  
Membrane Reactor ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Manganese Concentration ◽  
Membrane Cleaning ◽  
Chemical Washing ◽  
Pre Treatment ◽  
Solid Liquid ◽  
Solid Liquid Separation

We have developed a novel biofilm-membrane reactor (BMR) in which a nitrifying biofilm is fixed on the surface of a rotating membrane disk. With this reactor, both strict solid-liquid separation and oxidation of ammonia nitrogen can be simultaneously performed. Based on the results obtained in previous bench-scale experiments, a pilot-scale study was conducted using river water at a water purification plant. The results obtained in the pilot study can be summarized as follows. (1) By implementation of pre-treatment (coagulation and sedimentation) and simple membrane cleaning (sponge cleaning), the filter run could be continued for 17 months without any chemical washing. (2) Sufficient nitrification was observed when water temperature was high. Deterioration in nitrification efficiency during winter was reduced by the addition of phosphorus. (3) In addition to nitrification, biological oxidation of AOC and manganese can be expected with the BMR. In this study, both AOC and manganese concentration in the permeate decreased to a level less than 10 μg/L. (4) Irreversible membrane fouling, which was thought to be mainly caused by manganese, became significant as the operation period became longer.

scholarly journals Quantifying the Effect of COD to TN Ratio, DO Concentration and Temperature on Filamentous Microorganisms’ Population and Trans-Membrane Pressure (TMP) in Membrane Bio-Reactors (MBR)

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1514
Author(s):  
Petros Gkotsis ◽  
Giannis Lemonidis ◽  
Manassis Mitrakas ◽  
Alexandros Pentedimos ◽  
Margaritis Kostoglou ◽  
...  
Keyword(s):  
Data Analysis ◽  
High Temperature ◽  
Membrane Fouling ◽  
Pilot Scale ◽  
Soluble Microbial Products ◽  
Mathematical Equation ◽  
Filamentous Microorganisms ◽  
Do Concentration ◽  
Microbial Products

Using moderate populations of filaments in the biomass of Membrane Bio-Reactors (MBRs) is a biological anti-fouling method which has been increasingly applied over the last few years. This study aims to quantify the effect of COD to TN ratio, Dissolved Oxygen (DO) concentration and temperature on filaments’ population and Trans-Membrane Pressure (TMP) in a pilot-scale MBR, with a view to reducing membrane fouling. The novelty of the present work concerns the development of a mathematical equation that correlates fouling rate (dTMP/dt) with the population of filamentous microorganisms, assessed by the Filament Index (FI), and with the concentration of the carbohydrate fraction of Soluble Microbial Products (SMPc). Apart from TMP and SMPc, other fouling-related biomass characteristics, such as sludge filterability and settleability, were also examined. It was shown that at high COD to TN ratio (10:1), low DO concentration in the filaments’ tank (0.5 ± 0.3 mg/L) and high temperature (24–30 °C), a moderate population of filaments is developed (FI = 1–2), which delays the TMP rise. Under these conditions, sludge filterability and settleability were also enhanced. Finally, TMP data analysis showed that the fouling rate is affected by FI and SMPc concentration mainly in the long-term fouling stage and increases exponentially with their increase.

Pilot scale evaluation of biofiltration as an innovative pre-treatment for ultrafiltration membranes for drinking water treatment

2011 ◽  
Vol 11 (1) ◽  
pp. 23-29 ◽  
Author(s):  
P. M. Huck ◽  
S. Peldszus ◽  
C. Hallé ◽  
H. Ruiz ◽  
X. Jin ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Drinking Water Treatment ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Membrane Unit ◽  
Ozone Addition ◽  
Pre Treatment ◽  
Uf Membranes

Fouling remains one of the major constraints on the use of low pressure membranes in drinking water treatment. Work over the last few years has shown the importance of biopolymers (carbohydrates and protein-like material) as foulants for ultrafiltration (UF) membranes. The purpose of this study was to investigate at pilot scale the use of rapid biofiltration (without prior coagulation or ozone addition) as an innovative pretreatment to reduce fouling of UF membranes. The investigation was carried out on a water with a higher than average DOC and significant temperature variation. The biofilters, each operated at a hydraulic loading of 5 m/h, had empty bed contact times of 5, 10 and 15 minutes. The membrane unit was operated at a flux equivalent to 60 LMH at 20°C. The investigation confirmed the encouraging results obtained in an earlier smaller scale study with essentially the same water. Increased biofiltration contact time (i.e. increased bed depth) led to lower rates of hydraulically irreversible fouling. The initial biofiltration backwash procedure, involving air scour as is common in chemically assisted filtration, led in some cases to an increased rate of membrane fouling immediately after the backwash. An alternative backwashing strategy was developed, however the feasibility of operating with this approach over very long periods of time needs to be confirmed. To assist in full-scale implementation of this “green” and simple pretreatment, the design and operating conditions for the biofilters should be optimized for various types of waters. It is expected that biofiltration pretreatment will be of particular interest for small and/or isolated systems where a higher initial capital cost may be acceptable because of operational simplicity and reduced chemical requirements.

Understanding membrane fouling in ultrafiltration of WWTP-effluent

2000 ◽  
Vol 41 (10-11) ◽  
pp. 345-353 ◽  
Author(s):  
J.H. Roorda ◽  
J.H. van der Graaf
Keyword(s):  
Membrane Fouling ◽  
Waste Water Treatment ◽  
Rapid Decrease ◽  
Short Term ◽  
Chemical Cleaning ◽  
Water Treatment Plants ◽  
Wwtp Effluent ◽  
Pre Treatment ◽  
Cleaning Methods

The application of ultrafiltration to effluent of waste water treatment plants (WWTP-effluent) is getting increasing attention. However, many experiments show a rapid decrease in flux urging frequent and intensive cleaning. In order to understand the mechanisms of the occurring fouling process, various filtration and cleaning experiments were performed, giving information about the filterability of the feedwater (F) and the reversibility of the occurring fouling layer (R). Short-term fluxes are mainly determined by the filterability, while both the filterability and the reversibility greatly affect long-term fluxes. The objective of this research is to measure the filterability of WWTP-effluent and the reversibility of the occurring fouling layer in ultrafiltration of wwtp-effluent with and without pre-treatment. The results of the filtration experiments show a rapid decrease of flux resulting in a low value for the filterability, which also decreases during progressing filtration. The filterability is mainly related to the volume of treated water. Pre-treatment of the WWTP-effluent by in-line coagulation or by deep-bed filtration has little influence on the filterability. However, results on the reversibility show an improvement of the reversibility by pre-treatment. Both filterability of the WWTP-effluent and reversibility of the fouling layer are found to be independent of the applied flux. As to the applied cleaning methods, the back flush is far more effective than the forward flush even if combined with air. In all experiments the remaining fouling layer still has to be removed by an intensive chemical cleaning. This research indicates the very importance of reducing the formation of an irreversible, non-removable fouling layer.

The fate of organic micropollutants during long-term/long-distance river bank filtration

2016 ◽  
Vol 545-546 ◽  
pp. 629-640 ◽  
Author(s):  
Enrico Hamann ◽  
Pieter J. Stuyfzand ◽  
Janek Greskowiak ◽  
Harrie Timmer ◽  
Gudrun Massmann
Keyword(s):  
Bank Filtration ◽  
Organic Micropollutants ◽  
Long Distance ◽  
River Bank ◽  
River Bank Filtration

Fouling potential of lipopolysaccharides released at low temperatures in MBRs

2020 ◽  
Vol 81 (3) ◽  
pp. 529-534
Author(s):  
T. Kakuda ◽  
H. Iwasaki ◽  
K. Kimura
Keyword(s):  
Membrane Fouling ◽  
Low Temperatures ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Synthetic Wastewater ◽  
Efficient Operation ◽  
Term Operation ◽  
Key Factor ◽  
The Impact

Abstract Sludge filterability in membrane bioreactors (MBRs) fluctuates and affects membrane fouling. Therefore, understanding the reasons for the fluctuations of sludge filterability is important for the efficient operation of MBRs. In this study, a pilot-scale MBR treating municipal wastewater was operated for about 600 days and the variations in sludge filterability were continuously monitored by batch-filtration experiments using the same membranes as in the MBR. To investigate the reasons for the deterioration of sludge filterability, constituents in sludge supernatant were intensively monitored, and the correlations with sludge filterability were determined. The concentration of lipopolysaccharides (LPS) in sludge supernatant exhibited significantly higher correlation with sludge filterability than did conventional indexes (i.e. polysaccharides and proteins). Size fractions affecting MBR sludge filterability were also investigated, and it was suggested that colloidal LPS deteriorated MBR sludge filterability. Based on the long-term operation of the MBR, increase in colloidal LPS under low temperatures of the mixed liquor suspension was a key factor in the deterioration of sludge filterability. The impact of LPS increasing under low temperatures should be investigated by operating bench-scale MBRs fed with synthetic wastewater in controlled conditions.

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