The role of pH on the ultrafiltration for drinking water production in Algarve (Portugal)

2002 ◽  
Vol 2 (5-6) ◽  
pp. 367-371 ◽  
Author(s):  
M. Ribau Teixeira ◽  
H. Lucas ◽  
M.J. Rosa

The effect of the pH on the ultrafiltration performance of natural surface waters with moderate NOM content was evaluated at a laboratory scale using a plate-and-frame polysulphone membrane of 47 kDa MWCO. The results at three different pH values (acid, neutral and basic) demonstrated the important role of the pH on the ultrafiltration (UF) performance controlling the membrane - fouling matter interactions. The higher fluxes and lower natural organic matter (NOM) rejections obtained, at basic pH when compared to acid pH, are explained in terms of the variation of membrane and NOM charge, due to electrostatic repulsion and adsorption effects.

2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.


Desalination ◽  
2004 ◽  
Vol 169 (3) ◽  
pp. 223-230 ◽  
Author(s):  
I. Mijatović ◽  
M. Matošić ◽  
B. Hajduk Černeha ◽  
D. Bratulić

Desalination ◽  
2004 ◽  
Vol 169 (3) ◽  
pp. 223-230 ◽  
Author(s):  
I MIJATOVIC ◽  
M MATOSIC ◽  
B HAJDUKCERNEHA ◽  
D BRATULIC

2020 ◽  
Vol 6 (3) ◽  
pp. 779-794 ◽  
Author(s):  
Anna Andersson ◽  
Elin Lavonen ◽  
Mourad Harir ◽  
Michael Gonsior ◽  
Norbert Hertkorn ◽  
...  

Disinfection by-products (DBPs) are potentially toxic compounds formed upon chemical disinfection of drinking water. This study evaluate how treatment approaches affect DBP formation and composition.


2021 ◽  
Author(s):  
Carolin Reitter ◽  
Heike Petzoldt ◽  
Andreas Korth ◽  
Felix Schwab ◽  
Claudia Stange ◽  
...  

AbstractWorldwide, surface waters like lakes and reservoirs are one of the major sources for drinking water production, especially in regions with water scarcity. In the last decades, they have undergone significant changes due to climate change. This includes not only an increase of the water temperature but also microbiological changes. In recent years, increased numbers of coliform bacteria have been observed in these surface waters. In our monitoring study we analyzed two drinking water reservoirs (Klingenberg and Kleine Kinzig Reservoir) over a two-year period in 2018 and 2019. We detected high numbers of coliform bacteria up to 2.4 x 104 bacteria per 100 ml during summer months, representing an increase of four orders of magnitude compared to winter. Diversity decreased to one or two species that dominated the entire water body, namely Enterobacter asburiae and Lelliottia spp., depending on the reservoir. Interestingly, the same, very closely related strains have been found in several reservoirs from different regions. Fecal indicator bacteria Escherichia coli and enterococci could only be detected in low concentrations. Furthermore, fecal marker genes were not detected in the reservoir, indicating that high concentrations of coliform bacteria were not due to fecal contamination. Microbial community revealed Frankiales and Burkholderiales as dominant orders. Enterobacterales, however, only had a frequency of 0.04% within the microbial community, which is not significantly affected by the extreme change in coliform bacteria number. Redundancy analysis revealed water temperature, oxygen as well as nutrients and metals (phosphate, manganese) as factors affecting the dominant species. We conclude that this sudden increase of coliform bacteria is an autochthonic process that can be considered as a mass proliferation or “coliform bloom” within the reservoir. It is correlated to higher water temperatures in summer and is therefore expected to occur more frequently in the near future, challenging drinking water production.HighlightsColiform bacteria proliferate in drinking water reservoirs to values above 104 per 100 mlThe genera Lelliottia and Enterobacter can form these “coliform blooms”Mass proliferation is an autochthonic process, not related to fecal contaminationsIt is related to water temperature and appears mainly in summerIt is expected to occur more often in future due to climate changeGraphical abstract


2019 ◽  
Vol 5 (12) ◽  
pp. 2242-2250
Author(s):  
Xue Shen ◽  
Baoyu Gao ◽  
Kangying Guo ◽  
Qinyan Yue

Coagulation prior to the ultrafiltration (UF) process was implemented to improve natural organic matter (NOM) removal and membrane permeability.


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