Comparison of two polarity measurements of hydrophobic organic matter for the evaluation of water treatment processes: XAD resin and PRAM

2012 ◽  
Vol 66 (11) ◽  
pp. 2418-2424 ◽  
Author(s):  
Marc Philibert ◽  
Fernando Rosario-Ortiz ◽  
Mel Suffet
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Solid Phase ◽  
Weight Fraction ◽  
Assessment Method ◽  
Adsorption Method ◽  
Acrylic Polymer ◽  
Xad Resin

Dissolved organic matter (DOM) is a mixture of thousands of organic molecules wide-ranging in molecular weight, polarity and physicochemical properties. DOM is responsible for multiple water treatment issues such as trihalomethane (THM) formation potential and membrane fouling. Two methods of evaluating the polarity of DOM are being used for water treatment application: a serial XAD resin adsorption method at acid pH and the polarity rapid assessment method (PRAM) by parallel solid phase extraction (SPE) cartridges at natural pH. These two methods have been described by their authors as able to define a hydrophobic fraction though they do so by sorption onto different types of material at different pHs. The first part of this study compared the PRAM and XAD methods and showed that the hydrophobic fractions defined by the two approaches were not correlated. This result highlighted the difficulties in defining fractions as ‘hydrophobic material’. It appeared that the sorbents for XAD-8 (an acrylic polymer containing oxygen) at pH <3 and C-18 (a pure hydrocarbon polymer coating on silica particles) at neutral or pH <3 did not retain similar hydrophobic fractions. This hypothesis was verified by fluorescence spectroscopy of the effluent of the XAD-8 resin and PRAM C-18 SPE cartridge. Finally the study concentrated on the use of fluorescence and ultrafiltration methods in series with PRAM to gain more insight into the structure and characteristics of the hydrophobic DOM present in drinking water sources. This evaluation showed that the smaller molecular weight fraction of DOM (<1 kDa) had a higher percentage of hydrophobic character and that the fluorescence-defined aromatic protein fraction was the most hydrophilic.

Characterization of the changes in polarity of natural organic matter using solid-phase extraction: introducing the NOM polarity rapid assessment method (NOM-PRAM)

2004 ◽  
Vol 4 (4) ◽  
pp. 11-18 ◽  
Author(s):  
F.L. Rosario-Ortiz ◽  
K. Kozawa ◽  
H.N. Al-Samarrai ◽  
F.W. Gerringer ◽  
C.J. Gabelich ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Solid Phase Extraction ◽  
Natural Organic Matter ◽  
Solid Phase ◽  
Rapid Assessment ◽  
Assessment Method ◽  
Phase Extraction ◽  
Rapid Assessment Method ◽  
Wide Range

A new technique has been developed to quickly monitor the changes in polarity of aqueous natural organic matter (NOM) using solid-phase extraction (SPE) cartridges. This paper introduces the NOM polarity rapid assessment method (PRAM). The PRAM technique characterizes changes in NOM polarity by monitoring the breakthrough curves from different SPE cartridges at UV254. The SPE cartridges used in this study include a wide range of polarity from non-polar C-18 materials to anion exchangers. Each individual cartridge run takes 10 minutes and requires about 15 ml of sample. The collected water sample matrix is not changed, i.e. all PRAM analyses were done under ambient conditions on the original sample. Polarity evaluation is completed without the sample being exposed to changes in sample conditions, such as pH, solvent extraction, sequential evaporations or freeze-drying. This technique was able to monitor the weekly changes in NOM polarity entering a water treatment plant and compares the effects of different water treatment processes on this material.

Application of composite flocculants for removing organic matter and mitigating ultrafiltration membrane fouling in surface water treatment: the role of composite ratio

2019 ◽  
Vol 5 (12) ◽  
pp. 2242-2250
Author(s):  
Xue Shen ◽  
Baoyu Gao ◽  
Kangying Guo ◽  
Qinyan Yue
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Surface Water ◽  
Membrane Permeability ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Ultrafiltration Membrane ◽  
Surface Water Treatment ◽  
Ultrafiltration Membrane Fouling

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

Specific Fluorescent Fingerprint of Organic Matter in Advanced Water Treatment and its Molecular Weight

2013 ◽  
Vol 448-453 ◽  
pp. 317-321 ◽  
Author(s):  
Jing Wen Cao ◽  
Shao Wei Liao ◽  
Chung Yi Chung ◽  
Hwa Sheng Gau ◽  
Chun Yen Chiu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Water Treatment ◽  
High Performance ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Excitation Wavelength ◽  
Source Water ◽  
Fluorescent Intensity ◽  
Treated Water

In this research, the UV absorbance values of wavelength at 210 and 254 nm, excitation emission fluorescent matrix were measured for source water and treated water in CCL (Cheng Ching Lake) water treatment plant during five months. The whole data produced from EEFM was analyzed by PARAFAC operated in MATLAB software. The variation of molecular weight for organic matter was measured by HPLC (high performance liquid chromatography) with UV and fluorescent detectors. Observed from the variation of UV210/UV254, high value in treated water compared with source water was found. More molecular weight less than 5 k Da was formed in the treated water with relative to source water. Also, both major components in source water were located at wavelengths of excitation/emission of 250/410 nm and 230/330 nm and those in treated water were 240/410 nm and 220/290 nm. Also, the fluorescent intensity, long excitation wavelength was higher than short excitation wavelength in source water. This phenomena was opposite with treated water.

Impact of dissolved oxygen concentration on membrane filtering resistance and soluble organic matter characteristics in membrane bioreactors

2008 ◽  
Vol 57 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Kyung-Nan Min ◽  
Sarina J. Ergas ◽  
Anna Mermelstein
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Dissolved Oxygen ◽  
Weight Fraction ◽  
Total Resistance ◽  
Soluble Organic Matter ◽  
Aerobic Conditions ◽  
Do Concentration ◽  
The Impact ◽  
Molecular Weight Fractions

This study investigated the impact of dissolved oxygen (DO) concentration on membrane filtering resistance, soluble organic matter (SOM) and extracellular polymeric substance (EPS) characteristics in a membrane bioreactor (MBR). A laboratory-scale MBR was operated under DO limited (0.2 mg L−1 DO) and fully aerobic (3.7 and 5.4 mg L−1 DO) conditions. Membrane filtering resistance was determined for the mixed liquor suspended solids (MLSS) and for resuspended microbial biomass after removing SOM. Regardless of the DO concentration, the cake resistance (Rc) was approximately 95 percent of the total resistance (Rt). The membrane cake resistance was found to decrease significantly after removing the SOM. The total resistance caused by the resuspended biomass was 29 percent of that caused by the MLSS under DO limited conditions, while the total resistance caused by resuspended biomass was 41 to 48 percent of that caused by the MLSS under fully aerobic conditions. Under DO limited conditions, SOM in the MLSS contained a larger amount of high molecular weight compounds, leading to higher cake resistance than under fully aerobic conditions. There was significant variation in the molecular weight fractions of the EPS, with no clear relationship with DO concentration. There was also no distinct relationship between membrane filtering resistance and molecular weight fraction of the EPS.

Membrane fouling propensity after adsorption as pretreatment in rainwater: a detailed organic characterisation

2008 ◽  
Vol 58 (8) ◽  
pp. 1535-1539 ◽  
Author(s):  
L. Sabina ◽  
B. Kus ◽  
H.-K. Shon ◽  
J. Kandasamy
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Building Blocks ◽  
Fulvic Acids ◽  
Humic And Fulvic Acids ◽  
Removal Efficiencies ◽  
Hydrophilic Compounds ◽  
Hydrophobic Fraction

Organic characterisation in rainwater was investigated in terms of dissolved organic carbon (DOC) and molecular weight distribution (MWD) after powdered activated carbon (PAC) adsorption. PAC adsorption was used as pretreatment to membrane filtration to reduce membrane fouling. The MW of organic matter in rainwater used in this study was in the range of 43,000 Da to 30 Da. Each peak of organic matter consisted of biopolymers (polysaccharides and proteins), humic and fulvic acids, building blocks, low MW acids (hydrolysates of humic substances), low MW neutrals and amphiphilics. Rainwater contained the majority of hydrophilic compounds up to 72%. PAC adsorption removed 33% of total DOC. The removal efficiencies of the hydrophobic and hydrophilic fractions after PAC adsorption were 50% and 27%, respectively. PAC adsorption was found to preferentially remove the hydrophobic fraction. The majority of the smaller MW of 1,100 Da, 820 Da, 550 Da, 90 Da and 30 Da was removed after PAC adsorption. The MFI values decreased from 1,436 s/L2 to 147 s/L2 after PAC adsorption. It was concluded that PAC adsorption can be used as a pretreatment to membrane filtration with rainwater.

scholarly journals Characterization of dissolved organic matter at a water treatment plant with closed systems in different seasons

2020 ◽  
Vol 20 (5) ◽  
pp. 2013-2020
Author(s):  
Hudori Hudori ◽  
Toshiro Yamada ◽  
Yukitaka Suzuki ◽  
Maulana Yusup Rosadi ◽  
Hiroto Tamaoki ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Water Treatment ◽  
Dissolved Organic Matter ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Raw Water ◽  
Recycled Water ◽  
Water Treatment Process ◽  
Closed Systems

Abstract This research focuses on characterizing the dissolved organic matter found at water treatment plants with closed systems. Recycled water generated as a by-product of water treatment is added to raw water in those systems. The dissolved organic matter in the raw water was found to be higher in summer than in winter, but the water treatment process was able to produce purified water of the similar quality in both seasons. The recycled water contained mostly low molecular weight and protein-like substances, and this composition was different from that of the raw water, which mainly contained humic-like substances. The recycled water did not influence the concentration of humic-like substances or the molecular weight distribution in the influent water.

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