Characterization of hydraulically reversible and irreversible fouling species in ultrafiltration drinking water treatment systems using fluorescence EEM and LC–OCD measurements

2013 ◽  
Vol 13 (5) ◽  
pp. 1220-1227 ◽  
Author(s):  
R. H. Peiris ◽  
M. Jaklewicz ◽  
H. Budman ◽  
R. L. Legge ◽  
C. Moresoli
Keyword(s):  
Drinking Water ◽  
Particulate Matter ◽  
Citric Acid ◽  
Water Treatment ◽  
Lake Water ◽  
Drinking Water Treatment ◽  
Metal Species ◽  
Chemical Cleaning ◽  
Membrane Cleaning

The application of the fluorescence excitation-emission matrix (EEM) approach and liquid chromatography–organic carbon detection (LC–OCD) analysis for the characterization of hydraulically reversible and irreversible fouling species, extracted from hollow fiber ultrafiltration (UF) membranes used in drinking water treatment, was demonstrated. Hydraulically reversible and irreversible fouling species were extracted from two pilot UF membrane systems operated in parallel with lake water as the feed. Two membrane cleaning protocols, hydraulic- and chemical-based (NaOCl and citric acid) cleaning, were considered. Colloidal/particulate matter together with protein-like and metal species in water appeared to contribute to the formation of a hydraulically removable fouling layer on the membranes. Hydraulically irreversible fouling, in contrast, was impacted considerably by humic substances (HS) and protein-like matter. The formation of an irreversible fouling layer was also likely influenced by interactions between the colloidal/particulate matter and metal species together with HS and protein-like matter. LC–OCD analysis revealed the presence of predominant levels of lower molecular weight HS-like matter – compared to the HS-like matter commonly present in lake water – in the citric acid extracted foulant fraction. The permeability loss due to hydraulically irreversible UF fouling was considerably greater than the permeability loss due to hydraulically reversible UF fouling. A permanent permeability loss (∼25–35% of the initial permeability) was present even after the application of considerably strong chemical cleaning protocols on both pilot systems. This study indicated that the fluorescence EEM approach can be applied for monitoring and characterization of membrane cleaning procedures and as a potential diagnostic tool for assessing the effectiveness of hydraulic- and chemical-based cleaning protocols employed in UF drinking water treatment operations using rapid off-line measurements. On the other hand, since the LC–OCD analysis technique is a comparatively time consuming method, it may be used for verification of the fluorescence EEM-based results of the foulant fractions.

scholarly journals Molecular Characterization of Human-Pathogenic Microsporidia and Cyclospora cayetanensis Isolated from Various Water Sources in Spain: a Year-Long Longitudinal Study

2012 ◽  
Vol 79 (2) ◽  
pp. 449-459 ◽  
Author(s):  
Ana Luz Galván ◽  
Angela Magnet ◽  
Fernando Izquierdo ◽  
Soledad Fenoy ◽  
Cristina Rueda ◽  
...  
Keyword(s):  
Drinking Water ◽  
Longitudinal Study ◽  
Water Treatment ◽  
Molecular Characterization ◽  
Drinking Water Treatment ◽  
Enterocytozoon Bieneusi ◽  
Content Type ◽  
Cyclospora Cayetanensis ◽  
Water Treatment Plants

ABSTRACTRecent studies suggest the involvement of water in the epidemiology ofCyclospora cayetanensisand some microsporidia. A total of 223 samples from four drinking water treatment plants (DWTPs), seven wastewater treatment plants (WWTPs), and six locations of influence (LI) on four river basins from Madrid, Spain, were analyzed from spring 2008 to winter 2009. Microsporidia were detected in 49% of samples (109/223),Cyclosporaspp. were detected in 9% (20/223), and both parasites were found in 5.4% (12/223) of samples. Human-pathogenic microsporidia were detected, includingEnterocytozoon bieneusi(C, D, and D-like genotypes),Encephalitozoon intestinalis,Encephalitozoon cuniculi(genotypes I and III), andAnncaliia algerae.C. cayetanensiswas identified in 17 of 20 samples. To our knowledge, this is the first study that shows a year-long longitudinal study ofC. cayetanensisin drinking water treatment plants. Additionally, data about the presence and molecular characterization of the human-pathogenic microsporidia in drinking water, wastewater, and locations of influence during 1 year in Spain are shown. It is noteworthy that although the DWTPs and WWTPs studied meet European and national regulations on water sanitary quality, both parasites were found in water samples from these plants, supporting the idea that new and appropriate controls and regulations for drinking water, wastewater, and recreational waters should be proposed to avoid health risks from these pathogens.

Characterization of organic matter and disinfection by-products in membrane backwash water from drinking water treatment

2009 ◽  
Vol 168 (2-3) ◽  
pp. 753-759 ◽  
Author(s):  
Lingling Zhang ◽  
Ping Gu ◽  
Zijie Zhong ◽  
Dong Yang ◽  
Wenjie He ◽  
...  
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
By Products

scholarly journals Improving chemical cleaning of fouled membranes in a drinking water treatment plant

2019 ◽  
Vol 19 (8) ◽  
pp. 2330-2337
Author(s):  
Susumu Hasegawa ◽  
Yasuhiro Tanaka ◽  
Naokazu Wake ◽  
Ryosuke Takagi ◽  
Hideto Matsuyama
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Humic Substances ◽  
Sodium Hypochlorite ◽  
Membrane Fouling ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Chemical Cleaning ◽  
Water Treatment Plants

Abstract Recently, membrane filtration systems have become increasingly common in drinking water treatment plants. In this industry, preventing membrane fouling is of utmost importance. Many studies on the relationship between raw water components and membrane fouling have been performed in laboratory conditions. However, very few studies have analyzed the components of foulants on the fouled membrane as operated in actual drinking water treatment plants. By analyzing these components in plant-conditions, membrane fouling will be more effectively prevented. In this study, we analyzed the components of foulants extracted with 0.1 N NaOH from a fouled membrane operated in a drinking water treatment plant in Japan. Our analysis revealed that the main foulants were humic substances. In order to dissolve the accumulated humic substances, additional chemical cleaning was attempted with 500 ppm sodium hypochlorite. As a result, it was found that humic substances were dissolved and filtration resistance significantly decreased. Additionally, the removal of inorganic foulants was also greater after chemical cleaning with 500 ppm sodium hypochlorite, as inorganic foulants trapped within humic substances were released to the membrane surface as hydroxides by the additional sodium hypochlorite cleaning and were dissolved by the periodic citric acid cleaning.

scholarly journals Influence of density flow on treated water turbidity in a sedimentation basin with inclined plate settler

2017 ◽  
Vol 17 (4) ◽  
pp. 1140-1148
Author(s):  
K. Takata ◽  
R. Kurose
Keyword(s):  
Drinking Water ◽  
Particulate Matter ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
Raw Water ◽  
Inclined Plate ◽  
Treated Water ◽  
Sedimentation Basin ◽  
Density Flow ◽  
Upward Velocity

The removal efficiency of particulate matter from a sedimentation basin with an inclined plate settler in drinking water treatment facilities is sometimes reduced by density flow caused by temperature increases in the raw water. In this study, the structure of the density flow and its prevention are investigated by means of three-dimensional computational fluid dynamics (CFD). The results of CFD show that upward velocity is uniform and normal operations are performed before the increase in inlet water temperatures. After the onset of a temperature increase in the raw water, the upward flow velocity on the inclined plate settler increases, especially in the upstream zone of the plate. This velocity increment has a strong correlation with increase in turbidity as a result of the overflow of particulate matter. The effects of the installation of baffle plates on the inclined plate settler to reduce turbidity were explored. The CFD results using baffle plates show a significant decrease in upward velocity on the inclined plate settler. This suggests that baffle plates are effective in suppressing the overflow of particulate matter. To verify the prediction by CFD, baffle plates were installed in a drinking water treatment facility. The results show that the turbidity of treated water was reduced by the proposed procedure.

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