Ozone-enhanced photocatalytic degradation of natural organic matter in water

2006 ◽  
Vol 6 (3) ◽  
pp. 53-61 ◽  
Author(s):  
P. Zhang ◽  
L. Jian
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Photocatalytic Degradation ◽  
Natural Organic Matter ◽  
Retention Time ◽  
Degradation Rate ◽  
Removal Rate ◽  
Water Source ◽  
Drinking Water Source ◽  
Toc Removal

Ozone-enhanced photocatalytic degradation of macromolecular natural organic matter (NOM) in drinking water source was investigated. The influences of ozone dosage, retention time and bicarbonate concentration on the NOM degradation rate were studied. The change of molecular weight distribution of NOM caused by ozone-enhanced photocatalysis was analysed, as well as the degradation rate of NOM with different molecular weight (MW). It was shown that ozone-enhanced photocatalysis was much better for NOM degradation than sole ozonation or photocatalysis. Increase of both ozone dosage and retention time could effectively increase the TOC removal rate, while biodegradability could be improved solely by an increase in ozone dosage. The existence of bicarbonate significantly reduced the photocatalytic degradation rate of NOM; however, its impact was effectively offset by the addition of ozone into the photocatalytic process. Macromolecular NOM was transformed into smaller molecules, and the larger NOM was mineralized by ozone-enhanced photocatalysis much faster than the smaller NOM.

Triclosan removal by NF from a real drinking water source – Effect of natural organic matter

2016 ◽  
Vol 283 ◽  
pp. 330-337 ◽  
Author(s):  
Abdullah Ogutverici ◽  
Levent Yilmaz ◽  
Ulku Yetis ◽  
Filiz B. Dilek
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Water Source ◽  
Drinking Water Source ◽  
Source Effect

Removal of Natural Organic Matter (NOM) from Drinking Water Supplies by Ozone-Biofiltration

1999 ◽  
Vol 40 (9) ◽  
pp. 157-163 ◽  
Author(s):  
Raymond M. Hozalski ◽  
Edward J. Bouwer ◽  
Sudha Goel
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Organic Carbon ◽  
Natural Organic Matter ◽  
Laboratory Experiments ◽  
Low Molecular Weight ◽  
Batch Experiments ◽  
Toc Removal ◽  
High Molecular Weight Material ◽  
Effects Of Temperature

Removal of natural organic matter (NOM) in biofilters can be affected by many factors including NOM characteristics, use of pre-ozonation, water temperature, and biofilter backwashing. Laboratory experiments were performed and a biofilter simulation model was developed for the purpose of evaluating the effects of each of these factors on NOM removal in biofilters. Four sources of NOM were used in this study to represent a broad spectrum of NOM types that may be encountered in water treatment. In batch experiments with raw NOM, the removal of organic carbon by biodegradation was inversely proportional to the UV absorbance (254 nm)-to-TOC ratio and directly proportional to the percentage of low molecular weight material (as determined by ultrafiltration). The extent and rate of total organic carbon (TOC) removal typically increased as ozone dose increased, but the effects were highly dependent on NOM characteristics. NOM with a higher percentage of high molecular weight material experienced the greatest enhancement in biodegradability by ozonation. The performance of laboratory-scale continuous-flow biofilters was not significantly affected by periodic backwashing, because backwashing was unable to remove large amounts of biomass from the filter media. Model simulations confirmed our experimental results and the model was used to further evaluate the effects of temperature and backwashing on biofilter performance.

Disinfection byproduct formation in reverse-osmosis concentrated and lyophilized natural organic matter from a drinking water source

2012 ◽  
Vol 46 (16) ◽  
pp. 5343-5354 ◽  
Author(s):  
Jonathan G. Pressman ◽  
Daniel L. McCurry ◽  
Shahid Parvez ◽  
Glenn E. Rice ◽  
Linda K. Teuschler ◽  
...  
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Reverse Osmosis ◽  
Natural Organic Matter ◽  
Water Source ◽  
Drinking Water Source ◽  
Disinfection Byproduct ◽  
Byproduct Formation

Characterization of proton and copper binding properties of natural organic matter from an Australian drinking water source by differential absorbance spectroscopy

2008 ◽  
Vol 8 (6) ◽  
pp. 611-614 ◽  
Author(s):  
D. J. Dryer ◽  
G. V. Korshin ◽  
A. Heitz ◽  
C. Joll
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Copper Concentration ◽  
Water Source ◽  
Drinking Water Source ◽  
Copper Binding ◽  
Suwannee River Fulvic Acid ◽  
Two Samples ◽  
Absorbance Spectra

This study examined the effects of changes in pH and copper concentration on the absorbance spectra of natural organic matter (NOM) from a reservoir in Western Australia. Differential absorbance spectra generated for this NOM under changing pH and copper concentration conditions revealed features that could be correlated to the activity of distinct types of chromophores. A comparison of results with those generated for experiments with standard Suwannee River fulvic acid highlighted important differences in chemistry between the two samples.

Comparative Study of Ozone Alone and Catalytic Ozonation for Transformation of Natural Organic Matter in River Water

2011 ◽  
Vol 183-185 ◽  
pp. 1312-1316
Author(s):  
Gang Wen ◽  
Jun Ma ◽  
Xing Fang
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Water Treatment ◽  
Comparative Study ◽  
River Water ◽  
Natural Organic Matter ◽  
Removal Rate ◽  
Catalytic Ozonation ◽  
Experimental Results ◽  
Promising Method

Ozone alone and catalytic ozonation of natural organic matter had been carried out in semibatch model reactor. The experimental results demonstrated that ozonation alone and catalytic ozonation are equivalent with minimization of natural organic matter(NOM), with the removal rate of TOC, UV254 about 7 % and 50 % respectively. But it is a promising method for changing the molecular weight and specially for enhancement of biodegradation. The AOC in river water was 233 ug L-1, which increase up to 325 ug L-1, 677 ug L-1, 633 ug L-1 in ozonation alone, catalytic ozonation (H2O2) and catalytic ozonation (ZnO) after 30 minutes reaction respectively. Through the research, it can be conclued that catalytic ozonation-BAC may be an promising way for water treatment.

Application of a fractionation technique for better understanding of the removal of natural organic matter by alum coagulation

2002 ◽  
Vol 2 (5-6) ◽  
pp. 427-433 ◽  
Author(s):  
J. van Leeuwen ◽  
C. Chow ◽  
R. Fabris ◽  
N. Withers ◽  
D. Page ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
High Performance ◽  
Relative Proportion ◽  
Water Source ◽  
Size Exclusion ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Alum Treatment ◽  
Hydrophobic Acids

To gain an improved understanding of the types of organic compounds that are recalcitrant to water treatment, natural organic matter (NOM) isolates from two drinking water sources (Mt. Zero and Moorabool reservoirs, Victoria, Australia) were separated into fractions of distinct chemical behaviour using resins. Four fractions were obtained from each water source and were organics absorbed to: (1) XAD-8 (very hydrophobic acids, VHA); (2) DAX-4 (slightly hydrophobic acids, SHA); (3) bound to an anion exchange resin (charged organics, CHAR); and (4) not absorbed or bound to resins (neutrals, NEUT). These fractions were then tested to determine the capacity of alum to remove them from water and to correlate this with the character of each isolate. The fractions were characterised by the application of high performance size exclusion chromatography (HPSEC), bacterial regrowth potential (BRP), trihalomethane formation potential (THMFP), pyrolysis gas-chromatography mass spectrometry (Py-GC-MS) and thermochemolysis. The highest removals of dissolved organic carbon (DOC) by alum treatment were in waters spiked with the CHAR fractions while the NEUT fractions were the most recalcitrant. The number average molecular weights (Mn) of DOC of the CHAR fractions before treatment were the highest, whilst those of the NEUT fractions were the lowest. After alum treatment, the Mn of the NEUT fractions were only slightly reduced. Results from Py-GC-MS and thermochemolysis indicate that the NEUT fractions had the highest relative proportion of saccharide derived organic material. Nonetheless, the BRP of waters spiked with the NEUT fractions differed markedly, indicating that organics recalcitrant to alum treatment can vary substantially in their chemical composition and capacity to support microbial growth.

Advanced oxidation processes: flowsheet options for bulk natural organic matter removal

2004 ◽  
Vol 4 (4) ◽  
pp. 113-119 ◽  
Author(s):  
C.A. Murray ◽  
S.A. Parsons
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Natural Organic Matter ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Oxidation Processes

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.

Removal of Humic Substances by Coagulation

1999 ◽  
Vol 40 (9) ◽  
pp. 47-54 ◽  
Author(s):  
C.R. O’Melia ◽  
W.C. Becker ◽  
K.-K. Au
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Complex Formation ◽  
Natural Organic Matter ◽  
Divalent Cations ◽  
Water Source ◽  
Quality Characteristic ◽  
Oxide Surfaces ◽  
Water Quality Characteristic ◽  
Coagulant Dosage

Measurements and modeling of the adsorption of natural organic matter (NOM) on oxide surfaces are presented and compared. Agreement is good and supports the view that the adsorption of NOM on oxides depends significantly on complex formation reactions between specific sites on oxide surfaces and functional groups on the NOM. Coagulant requirements can and often are set by the total organic carbon (TOC) concentration in a water source. Frequently there is a stoichiometric relationship between the required coagulant dosage and the TOC of the water to be treated. Other important factors include pH and the concentration of divalent cations. Ozone may benefit or retard coagulation, depending on coagulant type and the water quality characteristic that is dominant in setting the optimum coagulant dose.

scholarly journals Removal of Trihalomethane Precursors by Nanofiltration in Low-SUVA Drinking Water

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1370 ◽  
Author(s):  
Yael Dubowski ◽  
Roni Greenberg-Eitan ◽  
Menachem Rebhun
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Low Molecular Weight ◽  
Water Recovery ◽  
Formation Potential ◽  
Pressure Water ◽  
Membrane Type ◽  
Hydrophilic Organic Matter ◽  
By Products

Trihalomethanes (THMs) are prevalent disinfection by-products. High THM formation is usually associated with natural organic matter with high molecular weight and aromatic characteristics, which is efficiently removed by nanofiltration (NF). In the Sea of Galilee and the Israeli National Water Carrier (NWC), water shows high THM formation potential, although it mainly contains low molecular weight and hydrophilic organic matter with low aromaticity. In the present study, NF removal abilities were tested on treated NWC water using three different spiral wound membranes (NF90, NF270, and DL). Rejections and fluxes were tested as a function of pressure, water recovery, and membrane type. Feed and permeate dissolved organic carbon (DOC), UVA254, total THM formation (THMF), and total THM formation potential (THMFP), as well as alkalinity, conductivity, hardness, Ca2+, Mg2+, and Cl− were measured to evaluate rejection and THM formation reduction. The results demonstrated that NF can efficiently remove natural organic matter (NOM) and reduce THM formation, even in this challenging type of water. At low water recovery, membranes showed average rejection of about 70–85% for THMFP and THM. Upon elevating recovery, average THM and THMFP rejection decreased to 55–70%, with THM content still well below regulation limits. Of the membranes tested, the higher permeability of NF270 appears to make it economically favorable for the applications tested in this work.

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