The fate of natural organic matter during UV/H2O2 advanced oxidation of drinking waterA paper submitted to the Journal of Environmental Engineering and Science.

2009 ◽  
Vol 36 (1) ◽  
pp. 160-169 ◽  
Author(s):  
Siva Sarathy ◽  
Madjid Mohseni

At conditions within the range of those typically applied for commercial drinking water applications, the impact of ultraviolet and hydrogen peroxide (UV/H2O2) advanced oxidation (AO) on the concentration, spectral characteristics, hydrophobicity, and biodegradability of natural organic matter (NOM) in a raw surface water and ultrafiltered surface water was studied. At an initial H2O2 dose of 20 mg L–1, UV/H2O2 mineralized less than 15% of the NOM in raw surface water at a fluence of 1500 mJ cm–2. Natural organic matter in ultrafiltered surface water was mineralized by at least 27% after about 1500 mJ cm–2. Partial oxidation of NOM led to ring opening of aromatic structures, cleavage of conjugated double bonded carbon structures, and reduction in the degree of aromatic substitution. The UV/H2O2 AO preferentially reacted with hydrophobic fractions of NOM leading to the formation of hydrophilic products. The treatment oxidized recalcitrant NOM into more readily biodegradable compounds with significant increases in formaldehyde and acetaldehyde concentrations. Depending on NOM properties for a given water, UV/H2O2 AO may cause partial oxidation of NOM leading to the formation of biodegradable compounds. The presence of these species may need to be addressed with a downstream process capable of improving biological stability.

2008 ◽  
Vol 57 (12) ◽  
pp. 1999-2007 ◽  
Author(s):  
S. K. Maeng ◽  
S. K. Sharma ◽  
A. Magic-Knezev ◽  
G. Amy

Understanding the fate of effluent organic matter (EfOM) and natural organic matter (NOM) through riverbank filtration is essential to assess the impact of wastewater effluent on the post treatment requirements of riverbank filtrates. Furthermore, their fate during drinking water treatment can significantly determine the process design. The objective of this study was to characterise bulk organic matter which consists of EfOM and NOM during riverbank filtration using a suite of innovative analytical tools. Wastewater effluent-derived surface water and surface water were used as source waters in experiments with soil columns. Results showed the preferential removal of non-humic substances (i.e. biopolymers) from wastewater effluent-derived surface water. The bulk organic matter characteristics of wastewater effluent-derived surface water and surface water were similar after 5 m soil passage in laboratory column experiment. Humic-like organic matter in surface water and wastewater effluent-derived surface water persisted through the soil passage. More than 50% of total dissolved organic carbon (DOC) removal with significant reduction of dissolved oxygen (DO) was observed in the top 50 cm of the soil columns for both surface water and wastewater effluent-derived surface water. This was due to biodegradation by soil biomass which was determined by adenosine triphosphate (ATP) concentrations and heterotrophic plate counts. High concentrations of ATP in the first few centimeters of infiltration surface reflect the highest microbial activity which correlates with the extent of DOC reduction. Good correlation of DOC removal with DO and biomass development was observed in the soil columns.


2014 ◽  
Vol 15 (1) ◽  
pp. 34-41 ◽  
Author(s):  
J. Molnar ◽  
J. Agbaba ◽  
A. Tubić ◽  
M. Watson ◽  
M. Kragulj ◽  
...  

This work investigates the effects of ultraviolet (UV)/H2O2 advanced oxidation on the content and characteristics of natural organic matter (NOM) originating from two different groundwaters (3.03–9.69 mg/L total organic carbon (TOC), 2.71–4.31 Lmg−1m−1 specific ultraviolet absorbance (SUVA)). Application of UV irradiation resulted in a minor reduction in the total content of NOM. Using UV/H2O2 advanced oxidation led to a significant reduction of the aromatic character of NOM (SUVA was reduced by up to 80%) and an increase in the hydrophilic character of the residual NOM, with the optimal UV/H2O2 treatment conditions depending on the water type. In addition, fluctuations in trihalomethane formation potential (THMFP) were observed depending on the UV/H2O2 process conditions, with a maximal reduction of about 40% achieved for both waters.


2004 ◽  
Vol 4 (4) ◽  
pp. 113-119 ◽  
Author(s):  
C.A. Murray ◽  
S.A. Parsons

Advanced oxidation processes have been reported to have the potential to remove natural organic matter from source waters. Of these Fenton's reagent, photo-Fenton's reagent and titanium dioxide photocatalysis are the three most promising processes. Compared to conventional coagulation/flocculation processes they have higher removal efficiencies in terms of both dissolved organic carbon and UV254 absorbance. Under optimum reaction conditions all three remove over 80% dissolved organic carbon and 0% UV254 absorbance. In addition the enhanced removal of natural organic matter leads to a corresponding reduction in the formation of disinfection by-products following chlorination of the treated water. Advanced oxidation processes give enhanced removal of organic species ranging from low to high molecular weight while coagulation/flocculation is inefficient at removing low molecular weight species. One additional benefit is all three processes produce less residuals compared to conventional coagulation, which is advantageous as the disposal of such residuals normally contributes a large proportion of the costs at water treatment works.


2019 ◽  
Vol 5 (12) ◽  
pp. 2242-2250
Author(s):  
Xue Shen ◽  
Baoyu Gao ◽  
Kangying Guo ◽  
Qinyan Yue

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


2002 ◽  
Vol 2 (5-6) ◽  
pp. 515-521 ◽  
Author(s):  
W. Liu ◽  
S.A. Andrews ◽  
J.R. Bolton ◽  
K.G. Linden ◽  
C. Sharpless ◽  
...  

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.


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