Influence of UV irradiation and UV/hydrogen peroxide oxidation process on natural organic matter fluorescence characteristics

2004 ◽  
Vol 4 (4) ◽  
pp. 41-46
Author(s):  
D.E.W. Hofbauer ◽  
S.A. Andrews
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Uv Irradiation ◽  
Distribution Systems ◽  
Molecular Size ◽  
Peroxide Oxidation ◽  
Fluorescence Characteristics ◽  
Molecular Size Distribution ◽  
Uv Lamps

Natural organic matter is ubiquitous in aquatic systems, and has long been associated with disinfection by-product (DBP) formation during chlorination in water treatment plants and distribution systems. In this study modelled water was irradiated with either ultraviolet (UV) lamps or with UV combined with the addition of hydrogen peroxide (H2O2). The changes in the fluorescence intensity between the pretreated and post-treated samples were measured to determine the changes in the molecular size distribution of this reactive fraction of NOM. It was determined that the UV/H2O2 process reduces the concentration of these potential DBP precursors more effectively than UV irradiation alone.

Fluorescence characteristics of natural organic matter in water under sequential exposure to UV irradiation/chlor(am)ination

2013 ◽  
Vol 14 (1) ◽  
pp. 22-30 ◽  
Author(s):  
Qianjun Guo ◽  
Zaili Zhang ◽  
Zhengbo Ma ◽  
Yongmei Liang ◽  
Wei Liu
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Uv Irradiation ◽  
Fluorescence Intensity ◽  
Fluorescence Spectra ◽  
Low Molecular Weight ◽  
Subsequent Reaction ◽  
Fluorescence Characteristics ◽  
Major Reaction ◽  
Molecular Weight Fractions

The organic matter in International Humic Substances Society Natural Organic Matter (IHSS NOM) water exposed to ultraviolet (UV) irradiation and chlor(am)ine sequentially under practically relevant conditions was characterized based on fluorescence spectra. IHSS NOM water exposed to UV irradiation or chlor(am)ine alone was also evaluated. Both chlor(am)ine alone and UV/chlor(am)ine exposure showed similar chlor(am)ine demand and fluorescence spectra. UV irradiation and UV/chlorine exposure diminished the fluorescence intensity of IHSS NOM water, while UV/chloramine exposure resulted in increased fluorescence intensity. When compared with the results obtained following chlor(am)ination alone, IHSS NOM water showed decreased chlorine decay and increased chloramine decay after UV irradiation/chlor(am)ination. Additionally, IHSS NOM water exposed to UV/chloramine and chloramine showed less disinfection by-product (DBP) formation than water subjected to UV/chlorine and chlorine. Overall, these findings indicate that UV irradiation degrades NOM molecules to low-molecular-weight fractions, facilitating the subsequent reaction with chlor-(am)ine. However, chlorine and chloramine play different roles in the reaction. Chlorine degradation and substitution dominates the process of UV/chlorine exposure, while chloramine substitution is the major reaction during UV/chloramine exposure.

Molecular size distribution of natural organic matter in raw and drinking waters

Chemosphere ◽  
2001 ◽  
Vol 45 (6-7) ◽  
pp. 865-873 ◽  
Author(s):  
T.K. Nissinen ◽  
I.T. Miettinen ◽  
P.J. Martikainen ◽  
T. Vartiainen
Keyword(s):  
Organic Matter ◽  
Size Distribution ◽  
Natural Organic Matter ◽  
Molecular Size ◽  
Drinking Waters ◽  
Molecular Size Distribution

Comparison of disinfection byproduct (DBP) formation from different UV technologies at bench scale

2002 ◽  
Vol 2 (5-6) ◽  
pp. 515-521 ◽  
Author(s):  
W. Liu ◽  
S.A. Andrews ◽  
J.R. Bolton ◽  
K.G. Linden ◽  
C. Sharpless ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carboxylic Acids ◽  
Natural Organic Matter ◽  
Uv Irradiation ◽  
Direct Action ◽  
Disinfection Byproduct ◽  
Pressure Medium ◽  
The Impact ◽  
As Effects

The impact of UV irradiation on disinfection byproduct (DBP) formation was investigated for low pressure, medium pressure and pulsed UV technologies using a broad range of UV doses. Four classes of DBPs (THMs, HAAs, aldehydes and carboxylic acids) were examined. This enabled the determination of effects resulting from the direct action of UV irradiation on natural organic matter (aldehydes, carboxylic acids) as well as effects on the ultimate formation of chlorinated DBPs (THMs and HAAs) from secondary chlorination. For doses of less than 1,000 mJ/cm2, UV irradiation did not affect THM and HAA formation in subsequent chlorination processes, however higher UV doses resulted in lower ultimate concentrations of THMs and HAAs. UV irradiation also resulted in the formation of aldehydes and carboxylic acids at UV doses above 500 mJ/cm2, compounds that are known to adversely effect drinking water biostability.

The molecular size of natural organic matter (NOM) determined by diffusivimetry and seven other methods

2002 ◽  
Vol 36 (4) ◽  
pp. 925-932 ◽  
Author(s):  
Per K Egeberg ◽  
Alfred A Christy ◽  
Morten Eikenes
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Molecular Size
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