• 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.

• Journal of Industrial Technology
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• v.31 no.B
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• pp.127-132
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• 2011

Humic substances is accounted for for the largest proportion in natural organic matter(NOM) and NOM is widely distributed in varying concentration in all aquatic and soil. They can affect water quality adversely in several ways by contributing undesirable color, complexing with metal and yielding metal concentrations exceeding normal solubility. Ozonation is one of the efficient treatments for degradation of humic substances which cause some problems in water treatment. Especially, the combination of ozone and granular activated carbon was applied to degradation humic acid in aquatic system. The aim of this work to test the available of acid-treated granular activated carbon as catalyst in the ozonation of humic acid.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.205-213
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• 2007

We have studied NOM(natural organic matters) adsorption and biodegradation on 3 kinds of activated carbon and a anthracite. Coal based activated carbon showed the highest DOC(dissolved organic carbon) adsorption capability and roconut(samchully), wood (pica) in the order among the 3 kinds of activated carbon(F400). The biomass amount and activity also showed on coal, wood and coconut based activated carbon in the order. Over 15 minutes EBCT(empty bed contact time) needed to achieve 10 to 17% average removal efficiency and $18\sim24%$ maximum removal efficiency of NOM biodegradation in biofilter using anthracite. Hydrophobic and below 10,000 dalton NOM was much easier to adsorb into the activated carbon than hydrophilic NOM, THMFP(trihalomethane formation potential) and BDOC (biodegradable dissolved organic carbon)$_{slow}$ were much easier than HAA5FP(haloacetic acid 5 formation potential) and $BDOC_{rapid}$ to adsorb into the activated carbon. Hydrophilic and below 1,000 dalton NOM was much easily biodegraded and HAA5FP and $BDOC_{rapid}$ was easier than THMFT and $BDOC_{slow}$ to biodegrade in the biofilter.

• Korean Journal of Environmental Biology
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• v.34 no.1
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• pp.48-55
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• 2016

This study investigates the effect of effluent organic matter (EfOM) from sewage wastewater treatment plants on estrogenic activity reduction of bisphenol A (BPA) by UV photolysis. The EfOM and Suwannee River natural organic matter (SR-NOM) as reference were isolated into hydrophobic (HPO), transphilic (TPI) and hydrophilic (HPI) fractions depending on polarity. The specific ultraviolet absorbance (SUVA) analysis indicated that EfOM showed similar properties to microbially derived organic matters with low hydrophobicity, which is different from SR-NOM having high hydrophobicity. UV irradiation upto 3 hr significantly reduced SUVA values of both EfOM and SR-NOM (p<0.0001), depending on the polarity of organic matters. In the absence of organic matters, the relative estrogenic activity (REA) of BPA ($5.0{\times}10^{-5}M$) was decreased from 86% to 63% by UV photolysis (2 hr). However, the decrease of mean REA was from 68% to 37% in the presence of organic matters, which was significantly independent on the type (EfOM or SR-NOM) and polarity (HPO, TPI or HPI) of organic matters (p>0.05). As a result, the reduced REA by UV photolysis of BPA with and without organic matters was 31% and 23%, respectively, suggesting that both EfOM and SR-NOM accelerated the photolytic reduction of BPA estrogenic activity.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.571-579
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• 2013

The aggregation behaviors of silver nanoparticles (AgNPs) and titanium dioxide ($TiO_2$) nanoparticles were investigated. Time-resolved dynamic light scattering (DLS) was used to study the initial aggregation of AgNPs and $TiO_2$ over a range of mono (NaCl) and divalent ($CaCl_2$) electrolyte concentrations. The effects of pH, initial concentration of NPs and natural organic matters (NOM) on the aggregation of NPs were also investigated. The aggregation of both nanoparticles showed classical Derjaguin-Landau-Verwey-Overbeek (DLVO) type behavior. Divalent electrolyte was more efficient in destabilize the AgNPs and $TiO_2$ than monovalent electrolyte. The effect of pH on the aggregation of AgNPs was not significant. But the aggregation rate of $TiO_2$ was much higher with increasing pH. Higher NPs concentration leads to faster aggregation. Natural organic matter (NOM) was found to substantially hinder the aggregation of both AgNPs and $TiO_2$. This study found that the aggregation behavior of AgNPs and $TiO_2$ are closely associated with environmental factors such as ionic strength, pH, initial concentration of NPs and NOM.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1046-1054
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• 2006

The raw water DOC contained 39.3% of hydrophilics, 42.9% of hydriophobic, and 17.8% of transphilic. The hydrophobic fraction in this raw water was mostly fulvic acid. Fulvic acid comprised of 62% and the rest was humic acid(38%). There was more carboxylic acid functional group(64%) than phenolic group(36%). HPI-N and HPI-C comprised of 17% and 22% in the hydrophilic portion, respectively. The fouling mechanisms on the membrane surface and into its porous structure were analyzed in terms of several kinetic models. In order to analyze the fouling kinetics, the various kinetic models described in this paper were used to fit the experimental results. The kinetic models and kinetic constants obtained for each operation condition. The permeate flux was rapidly declined by simultaneous pore blocking and cake formation. Also, the permeate flux declined with decreasing internal pore size resulted from organic deposition into the membrane pore. The results of the membrane fouling test using UF membrane according to NOM fractions. HPI-N caused more fouling than HPI-C. Humic acid caused more fouling than fulvic acid probably due to higher adsorption capacity. Since humic acid has higher adsorption capacity than fulvic acid, it would be more adsorbed onto the membrane pores.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.12
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• pp.1337-1344
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• 2007

In this research, we synthesized potassium ferrate(VI) acting as an oxidant, disinfectant, and coagulant, and used it to treat natural organic matter(NOM, HA and FA) in river water. The removal efficiencies obtained by $UV_{254}$ ranged from 20.7 to 73.6% for 10 mg/L HA and from 52.6 to 77.5% for 10 mg/L FA in Nakdong river sample as the ferrate dose varied from 2 to 46 mg/L(as Fe). However, the removal efficiencies by TOC analysis ranged from 0 to 20.3% for HA and from 0 to 26.6% for FA at the same ferrate doses. The removal efficiencies of NOM increased either with decreasing pH or with increasing temperature. The removal efficiency of HA by ferrate was comparable to those by traditional coagulants such as $Al_2(SO_4)_3{\cdot}18H_2O$, $FeSO_4{\cdot}7H_2O$, and FeO(OH). The reaction between ferrate and HA reached a steady state within 60 seconds, showing first-order with respect to the reaction time. The removal efficiencies of HA by traditional coagulants were improved by pretreatment of HA using a small amount of ferrate.

• Economic and Environmental Geology
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• v.53 no.4
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• pp.347-362
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• 2020

Iron (hydro)oxides in aqueous environments are primarily formed due to mining activities, and they are known to be typical colloidal particles disturbing surrounding environments. Among them, hematites are widespread in surface environments, and their behavior is controlled by diverse factors in aqueous environments. This study was conducted to elucidate the effect of environmental factors, such as ionic composition and strength, pH, and natural organic matter (NOM) on the behavior of colloidal hematite particles. In particular, two analytical methods, such as dynamic light scattering (DLS) and single-particle ICP-MS (spICP-MS), were compared to quantify and characterize the behavior of colloidal hematites. According to the variation of ionic composition and strength, the aggregation/dispersion characteristics of the hematite particles were affected as a result of the change in the thickness of the diffuse double layer as well as the total force of electrostatic repulsion and van der Walls attraction. Besides, the more dispersed the particles were, the farther away the aqueous pH was from their point of zero charge (PZC). The results indicate that the electrostatic and steric (structural) stabilization of the particles was enhanced by the functional groups of the natural organic matter, such as carboxyl and phenolic, as the NOM coated the surface of colloidal hematite particles in aqueous environments. Furthermore, such coating effects seemed to increase with decreasing molar mass of NOM. On the contrary, these stabilization (dispersion) effects of NOM were much more diminished by divalent cations such as Ca²⁺ than monovalent ones (Na⁺), and it could be attributed to the fact that the former acted as bridges much more strongly between the NOM-coated hematite particles than the latter because of the relatively larger ionic potential of the former. Consequently, it was quantitatively confirmed that the behavior of colloidal hematites in aqueous environments was significantly affected by diverse factors, such as ionic composition and strength, pH, and NOM. Among them, the NOM seemed to be the primary and dominant one controlling the behavior of hematite colloids. Meanwhile, the results of the comparative study on DLS and spICPMS suggest that the analyses combining both methods are likely to improve the effectiveness on the quantitative characterization of colloidal behavior in aqueous environments because they showed different strengths: the main advantage of the DLS method is the speed and ease of the operation, while the outstanding merit of the spICP-MS are to consider the shape of particles and the type of aggregation.

• Proceedings of the Korean Sanitation Conference
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• 2001.11a
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• pp.143-158
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• 2001

본 연구는 물 속에 함유된 유기물질(Natural Organic Matter : NOM)들이 소독 약제와 결합한 부산물의 제거방안과 효과적인 미생물제거 그리고 기존의 환경 약품 사용에 따른 슬러지 문제등을 해결할 수 있는 막분리기술의 실험을 통하여 가능성 및 경제성등을 검토코자한다.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.118-120
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• 2004