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.

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.

Differential Absorbance Spectroscopy in Studying Natural Organic Matter Reactivity in Disinfection By-Products Formation: Comparison and Applicability

2011 ◽  
Vol 383-390 ◽  
pp. 3719-3723
Author(s):  
Yan Fang Liu ◽  
Qi Shan Wang ◽  
Shang Chao Yue ◽  
Si Si Li
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Chlorine Dioxide ◽  
Linear Equations ◽  
Strongly Correlated ◽  
Raw Water ◽  
Weak Correlation ◽  
Chlorination Process ◽  
Absorbance Spectroscopy ◽  
By Products

This study compared the differential absorbance spectroscopy of the raw water oxidized with chlorine and chlorine dioxide to explore the reactions between oxidants and natural organic matter in disinfection by-products (DBPs) formation. The correlations between the differential absorbance at 272 nm (ΔA272) and 254 nm (ΔA254) and DBPs formation in chlorinated water were also examined, respectively. The intensity of the differential absorbance increased with increasing doses for both chlorine and chlorine dioxide. The sites in natural organic matter oxidized with chlorine and chlorine dioxidate are different. Unlike the well defined band at 272 nm and 254 nm in differential spectra of water oxidized with chlorine, a well defined band at 220 nm was found in water oxidized with chlorine dioxide. The behavior of -ΔA272 during chlorination process was determined to be strongly correlated with DBPs concentrations quantified by linear equations with R2 values > 0.95. A weak correlation (R2 value 254, indicating the formation of DBPs independent of destruction in UV-absorbing sites.

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).

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.

The interaction between natural organic matter in raw waters and pesticide residues: a three dimensional excitation–emission matrix (3DEEM) fluorescence investigation

2013 ◽  
Vol 67 (11) ◽  
pp. 2428-2436 ◽  
Author(s):  
David J. Beale ◽  
Nichola A. Porter ◽  
Felicity A. Roddick
Keyword(s):  
Organic Matter ◽  
Fluorescence Spectroscopy ◽  
Natural Organic Matter ◽  
Water Samples ◽  
Pesticide Residues ◽  
Three Dimensional ◽  
Water Sources ◽  
Raw Water ◽  
Excitation Emission Matrix ◽  
Humic Fractions

This paper examines the interaction between dissolved natural organic matter and pesticide residues, both of which are found in raw water sources, using three dimensional excitation–emission matrix (3DEEM) fluorescence spectroscopy. It was observed that pesticide residue at 0.1 mg L−1 formed a complex with humic-like fluorophores that are commonly found in raw water samples. Applying 3DEEM fluorescence to investigate the humic fractions, it was found that identification of changes in water sources was possible, and, importantly, the presence of a number of pesticides was able to be determined. In addition, the formation of this complex, and the influence of soluble cations and anions upon it, was shown to impact the efficiency of analytical extraction procedures for pesticides; however, 3DEEM fluorescence could be an approach to account for such losses.

Occurrence of 1,4-dioxane and MTBE in drinking water sources in Japan

2006 ◽  
Vol 6 (2) ◽  
pp. 47-53 ◽  
Author(s):  
D. Simazaki ◽  
M. Asami ◽  
T. Nishimura ◽  
S. Kunikane ◽  
T. Aizawa ◽  
...  
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Water Samples ◽  
Quality Standards ◽  
Raw Water ◽  
Water Quality Standards ◽  
Butyl Ether ◽  
Water Treatment Plants ◽  
Standard Value ◽  
Surface Water Samples

Nationwide surveys of 1,4-dioxane and methyl-t-butyl ether (MTBE) levels in raw water used for the drinking water supply were conducted at 91 water treatment plants in Japan in 2001 and 2002, prior to the revision of the drinking water quality standards. 1,4-dioxane was widely and continuously detected in raw water samples and its occurrence was more frequent and its concentrations higher in groundwater than in surface water. However, its maximum concentration in raw water was much lower than its new standard value (50 μg/L), which was determined as a level of 10−5 excessive cancer risk to humans. Trace levels of MTBE were also detected in several surface water samples.

scholarly journals Comparison of Three Solid Phase Materials for the Extraction of Carboxylic Acids from River Water Followed by 2D GC × GC-TOFMS Determination

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
G. O. Bosire ◽  
J. C. Ngila ◽  
H. Parshotam
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Natural Organic Matter ◽  
Solid Phase ◽  
Cooling Water ◽  
Raw Water ◽  
Aliphatic Carboxylic Acid ◽  
Hydrophobic Nature ◽  
Relationship Of

The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges.

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.

IN VITRO DNA BINDING STUDIES OF SELECTED HETEROCYCLIC COMPOUNDS

INDIAN DRUGS ◽  
2018 ◽  
Vol 55 (12) ◽  
pp. 24-26
Author(s):  
C Akhila ◽  
◽  
P Lalitha
Keyword(s):  
Dna Binding ◽  
Heterocyclic Compounds ◽  
Uv Spectroscopy ◽  
Binding Mode ◽  
Spectroscopic Technique ◽  
Binding Studies ◽  
Base Pairs ◽  
Dna Base ◽  
Dna Binding Studies

DNA binding studies of selected heterocyclic compounds belonging to the class of quinolinones, substituted quinolinones and thiones were carried out using ct-DNA. The binding nature of the compounds with DNA analyzed using UV-spectroscopy revealed the compounds to be DNA intercalators demonstrating the binding nature of compounds with DNA base pairs. This study is aimed at establishing a facile UV spectroscopic technique to arrive at the binding mode of DNA to ligands.

Determination of Hydrophobic and Hydrophilic Fractions of Natural Organic Matter in Raw Water of Jalalieh and Tehranspars Water Treatment Plants (Tehran)

2007 ◽  
Vol 7 (18) ◽  
pp. 2651-2655 ◽  
Author(s):  
M.A. Zazouli ◽  
S. Nasseri . ◽  
A.H. Mahvi . ◽  
A.R. Mesdaghinia . ◽  
M. Younecian . ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Natural Organic Matter ◽  
Raw Water ◽  
Water Treatment Plants
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