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 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).

Removal of Se(VI) from Raw Water by Ion Exchange Process

2012 ◽  
Vol 430-432 ◽  
pp. 941-948 ◽  
Author(s):  
Yong Sheng Shi ◽  
Yu Zhen Shi ◽  
Lin Wang
Keyword(s):  
Ion Exchange ◽  
Removal Rate ◽  
Exchange Process ◽  
Selenium Concentration ◽  
Quality Standard ◽  
Raw Water ◽  
Strong Base ◽  
Ion Exchange Process ◽  
Efficiency Cost ◽  
Easy Operation

Studies have been carried out on removal of Se(Ⅵ) from raw water by ion exchange process. The experiment results indicate that employment of strong-base anion exchange resin of 201×7 can receive a desirable result for Se removal. It is particularly true that the removal rate of Se(Ⅵ) can achieve more than 96% when the Se(Ⅵ) concentration in raw water is 100μg/L. This allows selenium concentration of the supply water in full conformity to the quality standard currently available for drinking water. Ion exchange process for Se removal has been proved to be competent for its efficiency, cost effectiveness and easy operation.

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.

Natural organic matter from catchment to drinking water: a case study of Pori waterworks, Finland

2008 ◽  
Vol 8 (6) ◽  
pp. 681-690 ◽  
Author(s):  
H. M. Szabo ◽  
I. Lindfors ◽  
T. Tuhkanen
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Raw Water ◽  
Lake Waters ◽  
Molecular Weight Fractions ◽  
Uv And Fluorescence Detection

In this study Natural organic matter (NOM) characteristics and variations of catchment samples (brooks and collector lakes) from Western Finland, and drinking water produced from the same catchment were examined. Seasonal and spatial NOM variations were followed by means of DOC and HPLC-SEC with UV and fluorescence detection. NOM decreased from drains to lakes by 35 to 75% and from drains to drinking water by 73 to 94%. Drains had a higher NOM content in summer and a lower NOM content in winter and spring. Lakes showed inverse patterns and had a higher NOM content in winter and spring and a lower NOM content in summer. HPLC-SEC separated 8 molecular weight fractions. In drains the HMW fractions represented up to 80% of the NOM, in lake waters HMW fractions accounted for 50 to 70% of the NOM. In drinking water IMW fractions dominated. Increased NOM in raw water during winter was associated with increased IMW fractions and the appearance of HMW fractions in drinking water, DOC increasing from 1.4 mg C/L in summer to 5.8 mg C/L in winter. SPH-Tryptophan correlated with the dissolved organic nitrogen and DOC of the samples. The drain affected by agriculture generally presented higher SPH-Tryptophan values than the unaffected drain.

Determination of Hydrophobic and Hydrophilic Fractions of Natural Organic Matter in Raw Water of Jalalieh and Tehranspars Water Treatment Plants (Tehran)

2007 ◽  
Vol 7 (18) ◽  
pp. 2651-2655 ◽  
Author(s):  
M.A. Zazouli ◽  
S. Nasseri . ◽  
A.H. Mahvi . ◽  
A.R. Mesdaghinia . ◽  
M. Younecian . ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Natural Organic Matter ◽  
Raw Water ◽  
Water Treatment Plants

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 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.

Application of a Magnetic Resin (MIEX) in Raw Water

2013 ◽  
Vol 361-363 ◽  
pp. 801-804
Author(s):  
Jian Wei Ma ◽  
Ya Rui Song
Keyword(s):  
Ion Exchange ◽  
Natural Organic Matter ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Raw Water ◽  
Nitrogen And Phosphorus ◽  
Dissolved Organic Matters ◽  
Primary Focus ◽  
Magnetic Ion ◽  
Magnetic Resin

The objective of this research was to compare enhanced coagulation with anion exchange for removal of natural organic matter (NOM) and bromide. Treatment with a magnetic ion exchange resin (MIEX) was the primary focus of this study. The performance of the magnetic ion exchange resin,MIEX, in the treatment of raw water was investigated. MIEX can effectively remove UV-absorbing substances DOC. The removal of organic substances is accompanied by the elimination of other undesirable components, such as nitrogen and phosphorus. The optimal process parameters are at resin doses of 5-10 mL L1and contact time of 10-15 min, as determined via jartests. Based on this study, MIEX treatment is a suitable and efficient pretreatment method for the removal of extra dissolved organic matters and nitrates in raw water .

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