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).

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) &lt; 10kD with one exception. About 13 of the colour is given by MWCO fractions &gt; 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.

scholarly journals Characteristics of dissolved organic matter in a water purification plant and distribution pipes

2019 ◽  
Vol 280 ◽  
pp. 03007 ◽  
Author(s):  
Toshiro Yamada ◽  
Maulana Yusup Rosadi ◽  
Hudori ◽  
Yukitaka Suzuki ◽  
Eri Ito ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Water Treatment ◽  
Dissolved Organic Matter ◽  
Three Dimensional ◽  
Quality Parameters ◽  
Raw Water ◽  
Treatment Unit ◽  
Treatment Processes ◽  
Doc Concentration

Dissolved organic matter (DOM) needs to be characterized todetermine the ability of a water treatment unit to reduce organic matter andits relationship to the levels of chlorine required for disinfection. Weinvestigated water quality parameters, including DOM, in a waterpurification plant and distribution pipes located in central Japan. Thedissolved organic carbon (DOC) concentration decreased from 0.73 mg/Lin raw water to 0.50 mg/L in purified water by conventional treatmentprocesses. The DOC of purified water decreased slightly in the pipesdownstream of the plant. The three-dimensional excitation-emission matrixfluorescence spectra showed some specific peaks for humic-like substancesand protein-like substances in all water samples, and the compositions ofDOM in purified water were close to those in raw water. However, therewas a peak of protein-like substances in purified and returned water, whichwas not observed for raw water. The fluorescence intensities of humic-likesubstances in purified water decreased downstream of the plant, while thefluorescence intensities of protein-like substances increased in the pipes. The measured molecular weight distributions of DOM in water presentedsome specific peaks, and DOM with a smaller molecular weight was noteasily removed by water treatment processes. There were positiverelationships between decreases in the intensities of some peaks andresidual chlorine decay.

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.

scholarly journals Understanding the behaviour of molecular weight fractions of natural organic matter to improve water treatment processes

2010 ◽  
Vol 10 (1) ◽  
pp. 59-68 ◽  
Author(s):  
I. Kristiana ◽  
B. P. Allpike ◽  
C. A. Joll ◽  
A. Heitz ◽  
R. Trolio
Keyword(s):  
Molecular Weight ◽  
Drinking Water ◽  
Organic Matter ◽  
Water Treatment ◽  
Natural Organic Matter ◽  
Drinking Water Treatment ◽  
Size Exclusion ◽  
Aromatic Character ◽  
Relative Contribution ◽  
Treatment Processes

Water utilities have experienced increasing pressure to minimise the formation of disinfection by-products (DBPs), as reflected in the increasingly stringent regulations and guidelines for the concentrations of DBPs in drinking water. Understanding the disinfection characteristics and molecular weight (MW) distribution of natural organic matter (NOM) will assist in the optimisation of drinking water treatment processes to minimise the formation of DBPs. This study investigated the disinfection behaviour of MW fractions of NOM isolated from a Western Australian source water. The NOM was fractionated and separated using preparative size exclusion chromatography (SEC) and the fractions were chlorinated in the presence of bromide ion. The larger MW fractions of NOM were found to produce the highest concentrations of DBPs (trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, and haloaldehydes), with the low MW fractions still producing significant amounts of these DBPs. The results also showed a trend of an increasing proportion of brominated DBPs with decreasing MW and aromatic character. Considering that the smaller MW fractions of NOM produce significant amounts of DBPs, with a higher relative contribution from brominated DBPs, water treatment processes need to be optimised for either bromide removal or the removal of aliphatic, small MW fractions of NOM, in order to meet DBP guidelines and regulations.

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.

Use of Biofiltration for Removal of Natural Organic Matter to Achieve Biologically Stable Drinking Water

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2011-2014 ◽  
Author(s):  
R. M. Hozalski ◽  
S. Goel ◽  
E. J. Bouwer
Keyword(s):  
Molecular Weight ◽  
Drinking Water ◽  
Organic Matter ◽  
Organic Carbon ◽  
Natural Organic Matter ◽  
Distribution System ◽  
Apparent Molecular Weight ◽  
Drinking Waters ◽  
Dismal Swamp ◽  
Weight Analysis

The presence of organic carbon in raw drinking waters can cause problems such as trihalomethane formation during disinfection with chlorine, regrowth of bacteria in the distribution system and reduced GAC adsorber bed life. This research concerns biofiltration for the removal of organic matter from drinking water sources. A major objective of this research is to examine how differences in the source and composition of the natural organic matter relate to the biodegradability of the natural organic matter and influence biofiltration effectiveness. Most of the organic matter in Dismal Swamp water, one of the four sources of organic matter to be evaluated in this study, has an apparent molecular weight in the 3-10 K range and the &lt; 0.5 K range as shown by an apparent molecular weight analysis using ultrafiltration. Aerobic batch biodegradation experiments were performed using Dismal Swamp water ozonated at a dose of 1 mg O3/mg TOC. A 30 % reduction in total organic carbon over an 11-day incubation period was observed.

Effect of coagulation and PAC pretreatment on the fouling of MF and UF

2010 ◽  
Vol 5 (2) ◽  
Author(s):  
L. Nie ◽  
H. Q. Chu ◽  
B. Z. Dong ◽  
Z. Liu
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Pore Size ◽  
Active Carbon ◽  
Water Samples ◽  
Total Organic Matter ◽  
Flux Decline ◽  
Uf Membranes ◽  
Powdered Active Carbon

The water samples were fractionated by PES ultrafiltration (UF) membranes with molecular weight cutoffs (MWCOs) of 10kDa□30kDa and PVDF UF membrane with MWCOs of 100kDa, and these permeates were filtrated by PVDF UF membrane with MWCOs of 150kDa and CA microfiltration (MF) membrane with a 0.1μm pore size, as to investigate influence of nature organic matter (NOM) with different MWCOs on flux. The results demonstrated that NOM larger than 30kDa accounting for 15% of total organic matter resulted in 86% of flux decline for MF and 54% for UF, respectively. It was shown that coagulation removed the NOM larger than 100kDa that resulted in over 40% of flux decline. As a result, in spite of removing only 10% of NOM, coagulation enhanced flux substantially. Powdered active carbon (PAC) removed NOM smaller than 30kDa that showed little contribution to flux decline. Therefore, PAC removed 76% of NOM but showed little contribution to enhance flux. It can be concluded that the effect of pretreatment on enhancing flux can not be depended on amounts of NOM removed but on its contribution to flux decline.

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.

Research on Characteristics Recognition of Organic Matter in Yellow River Reservoir Water

2011 ◽  
Vol 374-377 ◽  
pp. 987-990
Author(s):  
Jian Guang Liu ◽  
Meng Meng Feng ◽  
Yan Hao Zhang ◽  
Kai Li ◽  
Hui Liu
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Water Samples ◽  
Yellow River ◽  
Raw Water ◽  
Reservoir Water ◽  
River Reservoir ◽  
Determination Methods ◽  
River Reservoirs ◽  
Different Molecular Weight

Six water samples from different Yellow River reservoirs in Shandong were selected. The molecular weight distribution and type of organic matter were determined by using ultrafiltration, adsorption experiments and active bio-sand determination methods. The results show that the proportions of TOC and UV254Subscript text in different molecular weight intervals and the type of organic matter are different. But the proportion of adsorbable dissolved organic matter is the largest, which is more than 80%.In addition, the proportion of biodegradable organic matter (BDOC) is little, so the biodegradability of the raw water is not high.

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.

Sign in / Sign up

Export Citation Format

Share Document