Influence of Physical-Chemical Characteristics of Natural Organic Matter (NOM) on Coagulation Properties: An Analysis of Eight Norwegian Water Sources

1999 ◽  
Vol 40 (9) ◽  
pp. 89-95 ◽  
Author(s):  
Harsha Ratnaweera ◽  
Egil Gjessing ◽  
Eivind Oug
Keyword(s):  
Molecular Weight ◽  
Natural Organic Matter ◽  
Water Samples ◽  
Process Conditions ◽  
Chemical Characteristics ◽  
Raw Water ◽  
Physical Chemical ◽  
Coagulant Dosage ◽  
Molecular Weight Fractions ◽  
Original Water

Coagulation behaviour of eight natural water samples containing NOM is investigated to identify parameters influencing the process. A strong correlation between colour, DOC and UV-abs. was shown, regardless of the source and fractions. Coagulation of original water samples is discussed using analytical parameters in raw water and various molecular weight fractions. Over 40% of colour is given by NOM fractions with molecular weight cut-off (MWCO) < 10kD with one exception. About 13 of the colour is given by MWCO fractions > 50 kD for all waters. Larger NOM molecules required less coagulants per removed colour unit compared with smaller NOM molecules. Bulk NOM parameters and colloidal charges were identified to be the most descriptive parameters of the samples and the coagulability. The possibility to predict the optimum coagulant dosage for given process conditions is illustrated.

scholarly journals Characterization of Natural Organic Matter in Conventional Water Treatment Processes and Evaluation of THM Formation with Chlorine

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Kadir Özdemır
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Water Samples ◽  
Molecular Size ◽  
Apparent Molecular Weight ◽  
Yield Coefficient ◽  
Raw Water ◽  
Treatment Processes ◽  
Uf Membranes

This study investigates the fractions of natural organic matter (NOM) and trihalomethane (THM) formation after chlorination in samples of raw water and the outputs from ozonation, coagulation-flocculation, and conventional filtration treatment units. All the water samples are passed through various ultrafiltration (UF) membranes. UF membranes with different molecular size ranges based on apparent molecular weight (AMW), such as 1000, 3000, 10,000, and 30,000 Daltons (Da), are commonly used. The NOM fraction with AMW < 1000 Da (1 K) is the dominant fraction within all the fractionated water samples. Its maximum percentage is 85.86% after the filtration process and the minimum percentage is 65.01% in raw water samples. The total THM (TTHM) yield coefficients range from 22.5 to 42 μg-TTHM/mg-DOC in all fractionated samples, which is related to their specific ultraviolet Absorbance (SUVA) levels. As the molecular weight of the fractions decreased, the TTHM yield coefficients increased. The NOM fractions with AMW values less than 1 K had lower SUVA values (<3 L/mg·m) for all treatment stages and also they had higher yield of TTHM per unit of DOC. The NOM fraction with AMW < 1 K for chlorinated raw water samples has the highest yield coefficient (42 μg-TTHM/mg-DOC).

Natural organic matter from catchment to drinking water: a case study of Pori waterworks, Finland

2008 ◽  
Vol 8 (6) ◽  
pp. 681-690 ◽  
Author(s):  
H. M. Szabo ◽  
I. Lindfors ◽  
T. Tuhkanen
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Raw Water ◽  
Lake Waters ◽  
Molecular Weight Fractions ◽  
Uv And Fluorescence Detection

In this study Natural organic matter (NOM) characteristics and variations of catchment samples (brooks and collector lakes) from Western Finland, and drinking water produced from the same catchment were examined. Seasonal and spatial NOM variations were followed by means of DOC and HPLC-SEC with UV and fluorescence detection. NOM decreased from drains to lakes by 35 to 75% and from drains to drinking water by 73 to 94%. Drains had a higher NOM content in summer and a lower NOM content in winter and spring. Lakes showed inverse patterns and had a higher NOM content in winter and spring and a lower NOM content in summer. HPLC-SEC separated 8 molecular weight fractions. In drains the HMW fractions represented up to 80% of the NOM, in lake waters HMW fractions accounted for 50 to 70% of the NOM. In drinking water IMW fractions dominated. Increased NOM in raw water during winter was associated with increased IMW fractions and the appearance of HMW fractions in drinking water, DOC increasing from 1.4 mg C/L in summer to 5.8 mg C/L in winter. SPH-Tryptophan correlated with the dissolved organic nitrogen and DOC of the samples. The drain affected by agriculture generally presented higher SPH-Tryptophan values than the unaffected drain.

Formation of N-nitrosamines from chlorination and chloramination of molecular weight fractions of natural organic matter

2013 ◽  
Vol 47 (2) ◽  
pp. 535-546 ◽  
Author(s):  
Ina Kristiana ◽  
Jace Tan ◽  
Cynthia A. Joll ◽  
Anna Heitz ◽  
Urs von Gunten ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Molecular Weight Fractions

Application of MIEX® pre-treatment for ultrafiltration membrane process for NOM removal and fouling reduction

2005 ◽  
Vol 5 (5) ◽  
pp. 15-24 ◽  
Author(s):  
H.J. Son ◽  
Y.D. Hwang ◽  
J.S. Roh ◽  
K.W. Ji ◽  
P.S. Sin ◽  
...  
Keyword(s):  
Organic Matter ◽  
Removal Efficiency ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Reduction Rate ◽  
Chemical Characteristics ◽  
Permeate Flux ◽  
Physical Chemical ◽  
Sample Water ◽  
Original Water

In this study, pretreatment of organic matters with MIEX® was evaluated using bench-scale experimental procedures on three organic matters to determine its effect on subsequent UF or MF membrane filtration. For comparison, a coagulation process was also used as a pretreatment of UF or MF membrane filtration. Moreover, the membrane fouling potential was identified using different fractions and molecular weights (MW) of organic matter. From the removal property of MW organic matter by the coagulation process for the sample water NOM and AOM, the removal efficiencies of high MW organic matter were much higher than those of low MW organic matter. It was shown that the removal efficiency of high MW organic matter (more than 10 kDa) was lower than that of low MW organic matter for the MIEX® process. For the change of permeate flux by the pretreatment process, the MIEX®-UF process showed high removal efficiency of organic matter compared with the coagulation-UF processes, but a high reduction rate of permeate flux was presented through the reduction of removal efficiency of high MW organic matter. From sequential filtration test results to examine the effect of MW of organic matter on membrane fouling, we found that the membrane fouling occurred with high MW organic matter, and the DOC of organic matter less than 0.5 mg/L was acting as the membrane foulant. In sample water composed of low MW organic matter (less than 10 kDa), because the low MW organic matter of less than 10 kDa has a high removal efficiency by MIEX®, a low reduction rate of permeate flux is obtained compared with the coagulation-UF processes. In summary, research on the physical/chemical characteristics of original water is needed before a membrane pretreatment process is selected, and a pertinent pretreatment process should be used based on the physical/chemical characteristics of the original water.

Taste and chemical characteristics of low molecular weight fractions from tofuyo – Japanese fermented soybean curd

2018 ◽  
Vol 252 ◽  
pp. 265-270 ◽  
Author(s):  
Hanifah Nuryani Lioe ◽  
Ayano Kinjo ◽  
Shin Yasuda ◽  
Megumi Kuba-Miyara ◽  
Shinjiro Tachibana ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chemical Characteristics ◽  
Low Molecular Weight ◽  
Fermented Soybean ◽  
Soybean Curd ◽  
Molecular Weight Fractions

scholarly journals Assessment of Trihalomethane Formation in Chlorinated Raw Waters with Differential UV Spectroscopy Approach

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Kadir Özdemir ◽  
İsmail Toröz ◽  
Vedat Uyak
Keyword(s):  
Natural Organic Matter ◽  
Water Samples ◽  
Uv Spectroscopy ◽  
Linear Equations ◽  
Spectroscopic Technique ◽  
Uv Absorbance ◽  
Raw Water ◽  
Maximum Loss ◽  
Maximum Reaction ◽  
Differential Uv Spectroscopy

In this study, the changes in UV absorbance of water samples were characterized using defined differential UV spectroscopy (DUV), a novel spectroscopic technique. Chlorination experiments were conducted with water samples from Terkos Lake (TL) and Büyükçekmece Lake (BL) (Istanbul, Turkey). The maximum loss of UV absorbance for chlorinated TL and BL raw water samples was observed at a wavelength of 272 nm. Interestingly, differential absorbance at 272 nm (ΔUV272) was shown to be a good indicator of UV absorbing chromophores and the formation of trihalomethanes (THMs) resulting from chlorination. Furthermore, differential spectra of chlorinated TL waters were similar for given chlorination conditions, peaking at 272 nm. The correlations between THMs andΔUV272were quantified by linear equations withR2values >0.96. The concentration of THMs formed when natural organic matter is chlorinated increases with increasing time and pH levels. Among all THMs, CHCl3was the dominant species forming as a result of the chlorination of TL and BL raw water samples. The highest chloroform (CHCl3), dichlorobromomethane (CHCl2Br), and dibromochloromethane (CHBr2Cl) concentration were released per unit loss of absorbance at 272 nm at pH 9 with a maximum reaction time of 168 hours and Cl2/dissolved organic carbon ratio of 3.2.

NOM control options: the next generation

2004 ◽  
Vol 4 (4) ◽  
pp. 139-145 ◽  
Author(s):  
D.A. Fearing ◽  
J. Banks ◽  
D. Wilson ◽  
P.H. Hillis ◽  
A.T. Campbell ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Exchange Process ◽  
Uv Absorbance ◽  
Raw Water ◽  
Ion Exchange Process ◽  
Control Options ◽  
The Times ◽  
Magnetic Ion

Seasonal periods of high rainfall have been shown to cause elevated natural organic matter (NOM) loadings at treatment works. These high levels lead to difficulties in removing sufficient NOM to meet trihalomethane (THM) standards, and hence better alternative treatments are required. Here three options for the removal of NOM either by optimising current coagulation and pre- or post-coagulation have been studied. NOM can be isolated into fractions distinguished by their hydrophobic and hydrophilic characteristics. Previous studies have shown that certain fractions are more recalcitrant to treatment during the times of high loadings. By optimising coagulation for these fractions a staged coagulation is proposed, the results of which found that although no significant dissolved organic carbon (DOC) or UV absorbance at 254 nm (UV254) was observed filter run times were significantly increased. Secondly a novel magnetic ion exchange process (MIEX®) developed specifically for the removal of NOM was trialled and the results of a combination of ferric coagulation and MIEX® showed that although the final DOC of the water was not significantly reduced the THM formation potential (THMFP) was reduced by more than 50% for the lower molecular weight (MW) compounds that are known to be untreated by conventional coagulation. Finally the addition of a range of adsorbents including carbons, hydroxides and clays to both the raw water and the isolated low MW fraction showed that an increase in DOC and UV254 removal was achievable. The findings of the three trials showed that at the difficult to treat times of the year, optimised removal for the low MW fractions could prove to be vital if legislation is changed.

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