scholarly journals Progress, challenges, and opportunities in enhancing NOM flocculation using chemically modified chitosan: a review towards future development

2020 ◽  
Vol 6 (1) ◽  
pp. 45-61 ◽  
Author(s):  
Paripurnanda Loganathan ◽  
Michael Gradzielski ◽  
Heriberto Bustamante ◽  
Saravanamuthu Vigneswaran

Natural organic matter (NOM) occurs ubiquitously in water bodies and this can greatly affect feed or raw water quality (taste, colour, odour, bacterial growth). Chemically modified chitosan can effectively remove NOM by the flocculation process.

2001 ◽  
Vol 1 (4) ◽  
pp. 237-245 ◽  
Author(s):  
V. Gauthier ◽  
B. Barbeau ◽  
R. Millette ◽  
J.-C. Block ◽  
M. Prévost

The concentrations of suspended particles were measured in the drinking water of two distribution systems, and the nature of these particles documented. The concentrations of particulate matter were invariably found to be small (maximum 350 μg/L). They are globally in the very low range in comparison with dissolved matter concentrations, which are measured in several hundreds of mg/L. Except during special water quality events, such as turnover of the raw water resource, results show that organic matter represents the most important fraction of suspended solids (from 40 to 76%) in treated and distributed water. Examination of the nature of the particles made it possible to develop several hypotheses about the type of particles penetrating Montreal's distribution system during the turnover period (algae skeleton, clays). These particles were found to have been transported throughout the distribution systems quite easily, and this could result in the accumulation of deposits if their surface charge were ever even slightly destabilised, or if the particles were to penetrate the laminar flow areas that are fairly typical of remote locations in distribution systems.


2008 ◽  
Vol 8 (6) ◽  
pp. 681-690 ◽  
Author(s):  
H. M. Szabo ◽  
I. Lindfors ◽  
T. Tuhkanen

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.


2013 ◽  
Vol 6 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
E. R. Cornelissen ◽  
L. C. Rietveld

Abstract. To guarantee a good water quality at the customers tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research was to improve the biological stability of the produced water by incorporating anion exchange (IEX) for NOM removal. Different placement positions of IEX in the treatment lane (IEX positioned before coagulation, before ozonation or after slow sand filtration) and two IEX configurations (MIEX® and fluidized IEX (FIX)) were compared on water quality as well as costs. For this purpose the pre-treatment plant at Loenderveen and production plant Weesperkarspel of Waternet were used as a case study. Both, MIEX® and FIX were able to remove NOM (mainly the HS fraction) to a high extent. NOM removal can be done efficiently before ozonation and after slow sand filtration. The biological stability, in terms of assimilable organic carbon, biofilm formation rate and dissolved organic carbon, was improved by incorporating IEX for NOM removal. The operational costs were assumed to be directly dependent of the NOM removal rate and determined the difference between the IEX positions. The total costs for IEX for the three positions were approximately equal (0.0631 € m−3), however the savings on following treatment processes caused a cost reduction for the IEX positions before coagulation and before ozonation compared to IEX positioned after slow sand filtration. IEX positioned before ozonation was most cost effective and improved the biological stability of the treated water.


2007 ◽  
Vol 7 (18) ◽  
pp. 2651-2655 ◽  
Author(s):  
M.A. Zazouli ◽  
S. Nasseri . ◽  
A.H. Mahvi . ◽  
A.R. Mesdaghinia . ◽  
M. Younecian . ◽  
...  

1999 ◽  
Vol 40 (9) ◽  
pp. 47-54 ◽  
Author(s):  
C.R. O’Melia ◽  
W.C. Becker ◽  
K.-K. Au

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.


2021 ◽  
Author(s):  
Betul Aykut-Senel ◽  
Cihan Ozgur ◽  
Sehnaz Sule Kaplan-Bekaroglu ◽  
Nuray Ates

2016 ◽  
Vol 18 (4) ◽  
pp. 803-816 ◽  

<p>Natural organic matter (NOM) has been identified as the prominent precursor for disinfection by-products (DBPs) formation during chlorination. Various studies have shown that the characteristics of NOM influence the Trihalomethanes (THMs) formation mechanism. The present study represents NOM categorization in terms of total organic carbon (TOC), dissolved organic carbon (DOC), UV absorbance at 254 nm wavelengths (UV<sub>254</sub>) and specific ultraviolet absorbance (SUVA) to investigate the effects of NOM on THMs formation mechanism. The high rate of dependency was found for each representative of NOM with respect to water quality characteristics and operational condition of disinfection process. Values of SUVA and UV<sub>254</sub> is drastically reduced with respect from higher to a moderate chlorine dose which represent the chlorine contact is more predominant with hydrophobic fractions of NOM. The value of SUVA is decreasing with respect to temperature and reaction time, which reveled higher rate of utilization for hydrophobic fractions of NOM. Predictive modeling approach was carried out using multiple regression analysis with the combination of two surrogates at each stage of modeling with help of operational condition of disinfection process and water quality characteristics. The R<sup>2</sup> value of the model was found in the range of 0.927 to 0.937 from the developed model and a model could be recommended for prediction of THMs in drinking water.</p>


2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Muhammad Firdaus Kamal ◽  
Euis Nurul Hidayah

Kehadiran NOM menurunkan kualitas air baku untuk air minum dengan mengubah sifat organoleptik, mengganggu sistem pengendapan dan meningkatkan penggunaan koagulan, menyebabkan penyumbatan pada saringan dan distribusi air minum. Komponen NOM, seperti humic acids (HA) dan fulvic acids (FA) yang bereaksi dengan logam berat menyebabkan terbentuknya senyawa toksik dan berkontribusi terhadap pembentukan disinfection by products (DBPs) yang menyebabkan potensi adanya senyawa karsinogenik dalam pengolahan air minum secara konvensional. Salah satu metode penyisihan bahan organik dalam air adalah dengan peningkatan proses koagulasi, dengan pretreatment sebelum proses koagulasi. Tujuan dari penelitian ini adalah mengetahui pengaruh pre-oksidasi dan koagulasi terhadap penyisihan bahan organik pada air Kali Jagir yang digunakan untuk produksi air minum. Berdasarkan hasil analisis, konsentrasi TOC pada air baku sebesar 11,67  mg/liter dan nilai UV absorbansi 254 nm sebesar 0,10895 cm-1, sehingga diperoleh nilai SUVA sebesar 0,934 L/mg/cm, sehingga diketahui karakteristik pada air Kali Surabaya yang cenderung hidrofilik dengan berat molekul rendah dan kebanyakan bukan humik yang mengindikasikan bahwa air tersebut dihasilkan dari kegiatan domestik dan industri. Pada kombinasi pre-oksidasi dan koagulasi, CaOCl2 dengan dosis 25 mg/liter mampu menurunkan TOC dari 11,67 mg/liter menjadi 9,11 mg/liter, sedangkan permanganat dengan dosis 0,8 mg/liter hanya mampu menurunkan TOC dari 11,67 mg/liter menjadi 11,25 mg/liter. Kombinasi pre-oksidasi dan koagulasi mampu menurunkan bahan organik aromatik, ditunjukkan dengan nilai absorbansi UV210 air baku yaitu 1,4983 cm-1 menjadi 1,2720 cm-1 dengan pre-oksidasi KMnO4-koagulan Al2(SO4)3 dan 1,3152 cm-1 pada pre-oksidasi CaOCl2-koagulan Al2(SO4)3. Kata kunci: bahan organik alami, koagulasi, pre-oksidasi. The presence of NOM reduces air quality for drinking water with changes in organoleptic properties, deposition systems and increased use of coagulants, blockages in filters and distribution of drinking water. NOM components, such as humic acid (HA) and fulvic acid (FA) which are printed with heavy metals cause the formation of toxic compounds and contribute to product disinfection (DBPs) which produce potential carcinogenic compounds in conventional drinking water treatment. One method of removing organic matter in water is by increasing the coagulation process, with pretreatment before the coagulation process. The purpose of this study was to determine the effect of pre-oxidation and coagulation on the removal of organic material in Kali Jagir water used for the production of drinking water. Based on the results of the analysis, TOC concentration in raw water is 11.67 mg/liter and UV absorbance value 254 nm is 0.10895 cm-1, so that the SUVA value is 0.934 L/mg/cm, so it is known the characteristics of the Surabaya River water which tend to be hydrophilic with low molecular weight and most not humic which indicates that the water is produced from domestic and industrial activities. In a combination of preoxidation and coagulation, CaOCl2 with a dose of 25 mg/liter was able to reduce TOC from 11.67 mg/liter to 9.11 mg/liter, while permanganate at a dose of 0.8 mg/liter was only able to reduce TOC from 11,67 mg/liter to 11.25 mg/liter. The combination of preoxidation and coagulation is able to reduce aromatic organic matter, indicated by the absorbance value of UV210 of raw water, namely 1.4983 cm-1 to 1.2720 cm-1 with the KMnO4-coagulant Al2(SO4)3 and 1.3152 cm-1 preoxidation in preoxidation CaOCl2-coagulant (SO4)3. Keywords: natural organic matter, coagulation, pre-oxidation.


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