• Journal of Korean Society of Water and Wastewater
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• v.22 no.4
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• pp.467-473
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• 2008

Natural organic matter (NOM) removal by physico-chemical adsorption and biological oxidation was investigated in five slow sand filters with different media depths. Non-purgeable dissolved organic carbon(NPDOC) and $UV_{254}$ absorbance were measured to evaluate the characteristics of NOM removal at different filter depths. Removal efficiency of NOM was in the range of 10-40% throughout the operation time. At start-up of the filters packed with clean sand media, NOM was probably removed by physico-chemical adsorption on the surface of sand through the overall layer of filter bed. However, when Schumutzdecke layer was built up after 30 days operation, the major portion of NPDOC was removed by biological oxidation and/or bio-sorption in lower depth above 50 mm. NOM removal rate in the upper 50 mm filter bed was $0.82hr^{-1}$. It was about 20 times of the rate($0.04hr^{-1}$) in the deeper filter bed. Small portion of NPDOC could be removed in the deeper filter bed by both bio-sorption and biodegradation. SEM analysis and VSS measurement clearly showed the growth of biofilm in the deeper filter bed below 500 mm, which possibly played an important role in the NOM removal by biological activity besides the physco-chemical adsorption mechanism

• Journal of Energy Engineering
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• v.27 no.2
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• pp.70-80
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• 2018

Natural organic matter (NOM) is among the most common pollutant in underground and surface waters. It comprises of humic substances which contains anionic macromolecules such as aliphatic and aromatic compounds of a wide range of molecular weights along with carboxylic, phenolic functional groups. Although the concentration of NOM in potable water usually lies in the range of 1-10 ppm. Conventional treatment technologies are facing challenge in removing NOM effectively. The main issues are concentrated to low efficiency, membrane fouling, and harmful by-product formation. Ion-exchangers can be considered as an efficient and economic pretreatment technology for the removal of NOM. It not only consumes less time for pretreatment but also resist formation of trihalomethanes (THMs), an unwanted harmful by-product. This article provides a comprehensive review of ion exchange processes for the removal of NOM.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.1
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• pp.73-80
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• 2004

This study investigated the phenomena of membrane fouling by NOM and the effect of the fouling on removal of micro-pollutants. NOM has a great effect on decline of permeate flux. Permeate flow rate was reduced by 88% in RO and 34.8% in NF for 323hr operation period. Removal rate of $UV_{254}$, is 87.4% in RO and 78.5% in NF and removal rate of DOC is 42.7% in RO and 32.9% in NF for 2mg/l humic acid. Removal efficiency of the micro-pollutants by the RO and NF membranes fouled by humic acid was mostly lower than that by the new membrane. The concentration polarization which affects the flux and the rejection was thought to occur in the active layer of the membrane, as the membrane was getting fouled.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.367-376
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• 2014

This study assessed the removal efficiency of NOM which is known as the precursors of DBPs in advanced water treatment using the ceramic membrane filtration, introduced the first in the nation at the Y water treatment plant (WTP). It is generally well-known that the removal of NOM by MF Membrane is very low in water treatment process. But, the result of investigation on removal efficiency of NOM in advanced water treatment using the ceramic membrane was different as follows. The removal rate of organic contaminant by the ceramic membrane advanced water treatment was determined to be 65.5% for the DOC, 85.8% for UV254, and 77 to 86% for DBPFP. The removal rate of pre-ozonation was found to be 6 to 15% more effective compared with the pre-chlorination. The removal rate of DOC and $UV_{254}$ in biological activated carbon(BAC) process was over 50% and 75%, respectively although the rate was decreased 10 ~ 20% according to analysis items in converting from GAC to BAC.

• Journal of Environmental Science International
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• v.16 no.6
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• pp.671-675
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• 2007

The objective of this study was to clarify the characteristics of the removed micropollutant since the breakthrough of adsorption ability was occurred in biological activated carbon(BAC) process. The removal efficiency of DOC (Dissolved Organic Carbon) was 36 % in the breakthrough of BAC occurred by NOM (Natural Organic Matter). The most of removal DOC was found out the adsorbable and biodegradable DOC (A&BDOC). But it was not clear to remove by any mechanism because A&BDOC have simultaneously the adsorption of activated carbon and biodegradation by microorganism in BAC. The removal of bromophenol was examined with BAC and rapid sand filter, for investigation of DOC removal mechanism in the breakthrough of BAC. In this experiment, BAC filter has been operated for 20 months for the treatment of reservoir water. The BAC filter was already exhausted by NOM. Bromophenol, adsorbable and refractory matter, was completely removed by BAC filter. Therefore, it might be removed by the adsorption in BAC. Adsorption isotherms of bromophenol were compared to two BACs which was preloaded with 500 daltons and 3,000 daltons of NOM. BAC preloaded with 3,000 daltons of NOM was not decreased to the adsorbability of bromophenol but BAC preloaded with 500 daltons of NOM was greatly decreased to it. These result indicated that NOM of low molecular weight can be removed by adsorption after a long period of operation and the breakthrough by NOM in BAC. Therefore, micropollutants might be removed through adsorption by saturated BAC.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.3
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• pp.370-377
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• 2005

Dispersion of coagulant should be completed in a fraction of a second before the metal hydroxide precipitate has form. For the reason so-called pump diffusion flash mixing (PDFM) have been proposed, and PDFM is one of reasonable methods to quickly disperse the hydrolyzing metal salts. In this study, therefore, we attempt to understand the difference of removal characteristics of natural organic matter (NOM) between pump diffusion flash mixing (PDFM) and conventional rapid mixing (CRM) for coagulation in a water treatment system, and to enhance the removal of NOM through the improved mixing process. DOC and turbidity removal by PDFM higher than those by CRM, while SUVA value of water treated by PDFM was high as compared with that by CRM. Hydrophilic NOM was more effectively removed by PDFM than CRM, since charge neutralization effect increased by quick dispersion of coagulant. The DBP formation potentials due to NOM was effectively reduced by the improved mixing (i.e., PDFM) for coagulation and could be controlled through decrease in concentration of precursor rather than reduction of activity with disinfectant.

• Environmental Engineering Research
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• v.19 no.1
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• pp.1-8
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• 2014

Natural organic matter (NOM) is a primary component of fouling in low-pressure membrane filtration, either solely, or in concert with colloidal particles. Various preventive measures to interfere with NOM fouling have been developed and extensively tested, such as coagulation, oxidation, ion exchange, carbon adsorption, and mineral oxide adsorption. Therefore, this article aims to conduct a literature review covering the topics of low-pressure membrane processes, NOM characteristics and fouling behaviors, and diverse fouling control strategies. In-depth explanations and discussion are made regarding why some treatment options are able to remove NOM from source water, but do not reduce fouling. This review provides insight for hybridized membrane processes with respect to NOM removal and fouling mitigation in water treatment.

• Membrane Journal
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• v.14 no.2
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• pp.149-156
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• 2004

This work focused on the degradation of natural organic matter (NOM) present in lake water using a combined pkotocatalysisimicrofiltration (MF) process. The system performances were investigated in terms of organic removal efficiency and membrane permeability. The addition of iron oxide particles (IOP) into the photocatalytic membrane reactor improved initial NOM removal by sorption, but during photocatalysis the removal efficiency was reversed, probably due to the scattering of UV light by IOP. The modification of TiO$_2$ surfaces by IOP deposition was conducted to enhance the photocatalytic NOM removal efficiency. A minimal amount of Impregnation of IOP on TiO$_2$ surfaces was required to prevent the light scattering effect as well. The coating of MF membranes with IOP helped to improve the NOM removal efficiency while sorbing NOM by IOP. Regardless of tile operating conditions and particles addition examined, no significant fouling was occurring at a flux of 15 L/$m^2$-h during entire MF operation.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.5
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• pp.332-339
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• 2011

Effects of powdered activated carbon impregnated by iron oxide nano particle (Impregnated PAC) on the microfiltration (MF) membrane system performance in NOM removal from water were investigated in this study. A fluidized bed column was employed as a pretreatment of MF membrane process. The Impregnated PAC bed was stably maintained at an upflow rate of 63 m/d without leakage of the Impregnated PAC particles, which provided a contact time of 29 minutes. A magnetic ring at the upper part of the column could effectively hold the overflowing discrete particles. The Impregnated PAC column demonstrated a significant enhancement in the MF membrane performance in terms of fouling prevention and natural organic matter (NOM) removal. Trans-membrane pressure of the MF membrane increased to 41 kPa in 98 hours of operation, while it could be maintained at 12 kPa with the Impregnated PAC pretreatment. Removal of NOM determined by dissolved organic carbon and UV254 was also enhanced from 46% and 51% to 75% and 84%, respectively, by the pretreatment. It was found that the Impregnated PAC effectively removed a wide range of different molecular-sized organic compounds from size exclusion analysis.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1137-1143
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• 2006

In this study we investigated the removal characteristics of NOM and bromate formation characteristics in SOMT reactor. The system was recently developed as a novel ozone reactor and installed in SJ pilot plant. DOC values were decreased within 3% after treatment of 0.5~2.0 mg/L ozone dosage in SOMT reactor while the $UV_{254}$ value was 69% decreased at 2.0 mg/L ozone dosage. The composition of NOM was analysed by LC-OCD (Organic Cabon Detector) after ozone treatment in SOMT reactor to elucidate the variation of NOM character. Polysaccharide (more than 20,000 g/mol) fraction of NOM was decomposed while building blocks (350~500 g/mol) and neutral (less than 350 g/mol) fraction increased. Spiked bromide reacted with 0.5~2.0 mg/L ozone dosage in the SOMT reactor. The bromate formation was proportional to the ozone dosage ($R^2=0.978$) but not proportional to reaction time. The maximum concentration of formated bromate was not exceeded to 10% of spiked bromide concentration.