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

Evaluation of drinking water treatment processes focusing on natural organic matter removal and on disinfection by-product formation

2002 ◽  
Vol 2 (5-6) ◽  
pp. 459-464 ◽  
Author(s):  
S. Chae
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Water Treatment ◽  
Natural Organic Matter ◽  
High Performance ◽  
Drinking Water Treatment ◽  
Molecular Size ◽  
Product Formation ◽  
Size Exclusion ◽  
Activated Carbon Adsorption

The aim of this study was to characterize and compare natural organic matter (NOM) removal and disinfection by-product (DBP) formation in the drinking water treatment train that can give valuable information, while optimizing the treatment process. In this study, the determination of the hydrophobic (HPO), transphilic (THP) and hydrophilic (HPI) NOM distribution was used in parallel with more related drinking water parameters to compare the selected waters. High-performance size-exclusion chromatography (HPSEC) was applied to evaluate the relative changes of molecular size distribution of NOM in different treatment steps and source waters. This showed that the quantity, speciation and activated carbon adsorption of DBPs could vary not only by water quality, but also by the distribution and properties of the organic molecules that comprise NOM.

scholarly journals Factors Governing Biodegradability of Dissolved Natural Organic Matter in Lake Water

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2210
Author(s):  
Camille Crapart ◽  
Tom Andersen ◽  
Dag Olav Hessen ◽  
Nicolas Valiente ◽  
Rolf David Vogt
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Respiration Rate ◽  
Lake Water ◽  
C:N Ratio ◽  
Molecular Size ◽  
Time Lapse ◽  
Element Cycling ◽  
Rate Of Oxygen Consumption ◽  
Lake Waters

Dissolved Natural Organic Matter (DNOM) is a heterogeneous mixture of partly degraded, oxidised and resynthesised organic compounds of terrestrial or aquatic origin. In the boreal biome, it plays a central role in element cycling and practically all biogeochemical processes governing the physico-chemistry of surface waters. Because it plays a central role in multiple aquatic processes, especially microbial respiration, an improved understanding of the biodegradability of the DNOM in surface water is needed. Here the current study, we used a relatively cheap and non-laborious analytical method to determine the biodegradability of DNOM, based on the rate and the time lapse at which it is decomposed. This was achieved by monitoring the rate of oxygen consumption during incubation with addition of nutrients. A synoptic method study, using a set of lake water samples from southeast Norway, showed that the maximum respiration rate (RR) and the normalised RR (respiration rate per unit of carbon) of the DNOM in the lakes varied significantly. This RR is conceived as a proxy for the biodegradability of the DNOM. The sUVa of the DNOM and the C:N ratio were the main predictors of the RR. This implies that the biodegradability of DNOM in these predominantly oligotrophic and dystrophic lake waters was mainly governed by their molecular size and aromaticity, in addition to its C:N ratio in the same manner as found for soil organic matter. The normalised RR (independently of the overall concentration of DOC) was predicted by the molecular weight and by the origin of the organic matter. The duration of the first phase of rapid biodegradation of the DNOM (BdgT) was found to be higher in lakes with a mixture of autochthonous and allochthonous DNOM, in addition to the amount of biodegradable DNOM.

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).

Enhanced removal of natural organic matter via peroxidase-mediated oxidative coupling

2004 ◽  
Vol 4 (4) ◽  
pp. 33-40 ◽  
Author(s):  
Q. Huang ◽  
R.A. Pinto ◽  
D.J. Burlingame ◽  
J. Tang ◽  
W.J. Weber
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Oxidative Coupling ◽  
Molecular Size ◽  
Fulvic Acids ◽  
Hydroxyl Groups ◽  
Coupling Reactions ◽  
Flow Reactors ◽  
Stable Species ◽  
Oxidative Coupling Reactions

Oxidative coupling reactions mediated by horseradish peroxidase in solutions containing natural organic matter (NOM) comprised by model fulvic acids were performed in completely mixed batch and flow reactors. The subsequent removal of NOM by ultrafiltration was found to be significantly enhanced for solutions subjected to oxidative coupling. Spectroscopic examinations revealed that the fulvic acid molecules were effectively reconfigured by substantial conversion of aromatic hydroxyl groups into ether bonds via oxidative coupling. These conversions apparently result in cross-linking of NOM moieties to form stable species of greater molecular size, thus rendering them more readily removable by ultrafiltration. The results of this study suggest that catalyzed oxidative coupling reactions in combination with ultrafiltration can be developed into an effective scheme for NOM removal in water treatment operations.

Experimental Evaluation of Cationic Polyelectrolytes for Removing Natural Organic Matter from Water

1999 ◽  
Vol 40 (9) ◽  
pp. 71-79 ◽  
Author(s):  
Brian Bolto ◽  
Gudrun Abbt-Braun ◽  
David Dixon ◽  
Rob Eldridge ◽  
Fritz Frimmel ◽  
...  
Keyword(s):  
Organic Matter ◽  
Charge Density ◽  
Natural Organic Matter ◽  
Molecular Size ◽  
Cationic Polyelectrolyte ◽  
Size Exclusion ◽  
Cationic Polymers ◽  
Treatment Processes ◽  
Exclusion Chromatography ◽  
Alum Treatment

The effectiveness of water treatment processes in removing natural organic matter varies with the nature of the natural organic matter (NOM), its molecular size, polarity and charge density, and with properties of the raw water such as turbidity and hardness. In some cases conventional alum treatment is inefficient. We have compared NOM removals achieved by conventional and polymer-based processes in bench-scale treatment of reconstituted ground and surface waters of varying colour, made from NOM isolated from the same waters. NOM isolates were fractionated by adsorption on non-functionalised resins and an anion exchanger, and characterised by size exclusion chromatography. Jar tests with the isolated NOM compared coagulation with polyelectrolytes, alum, clays and metal oxides, with each of the inorganics being in conjunction with a polyelectrolyte. Jar tests on reconstituted waters with alum and/or cationic polyelectrolyte show synergistic benefits from combinations of the two. The more hydrophobic NOM fractions were the most easily removed by polymer. The performance of cationic polymers improved significantly with increasing charge density and molecular weight. An alum/polymer combination is the most attractive treatment option.

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.

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