• 한국광물학회지
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• 제18권2호
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• pp.117-125
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• 2005

산업체에서 사용하고 있는 칠러 냉각 장치에는 침전물이나 부유물이 많이 발생한다. 칠러 냉각장치에 마그네슘을 적용시켰을 때 나타나는 냉각수와 침전물 및 부유물의 변화를 연구하기 위하여 ICP-AES, IC, XRD, SEM 분석을 실시하였다. 칠러 냉각장치에 Mg를 적용할 경우 대부분의 용해 성분이 감소하는 경향을 보여주고 있어 냉각수의 수질이 상당히 개선되었다. 또한 유기물 형태로 존재하던 부유물이나 침전물이 거의 생성되지 않아 유기물 생성을 억제시키는 효과도 있는 것으로 판단된다.

• 한국환경보건학회지
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• 제27권2호
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• pp.60-66
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• 2001

Natural organic matters(NOMs) are found everywhere such as soil, surface and ground waters and consist of both humic and nonhumic components, and their heterogeneith makes each source unique. This study was carried to evaluate the removal characteristics of NOMs by mixing coagulants and the variation of apparent molecular weight distribution(AMWD) in coagulation process. Ratio of optimum coagulants dosage for removal of DOC and turbidity by mixing coagulants was 1.83 mM F $e^{3+}$/mM $Al^{3+}$. DOC removal increased at lower pH. The pH6 control focused on the removal of organic matters could reduce the amount of coagulant consumption by 2 to 3 times based on the pH8.5 of natural water. The dissolved organic matters in the natural water from the mid-stream of Han River were composed of the low molecular weight(LMW,<1 K) of 59.7%, and the medium and high molecular weight(M.HMW, 1~30 K) of 40.3%, respectively. At pH6, the DOC removal efficiencies of LMW(<1 K) and M.HMW(1~30 K) in coagulation process were 27~35%, 62~72%, respectively. The fraction smaller than 1 K was not eliminated to a noticeable degree, while the fraction of 1~30 K was relatively well removed. In conclustion, mixing coagulants were fairly effective in the removal of natural organic matter.r.

• 멤브레인
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• 제21권2호
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• pp.127-140
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• 2011

본 연구에서는 정수처리용 세라믹 한외여과 및 광촉매의 혼성공정에서 $TiO_2$ 광촉매 코팅 구(bead)의 농도 및 물역세척 주기(FT), 물역세척 시간(BT) 변화의 영향을 알아보았다. 광촉매 코팅 구의 농도는 10~40 g/L로, FT는 2~10분으로, BT는 6~30초로 변화시키면서, 그 영향을 180분 운전 후 막오염에 의한 저항$(R_f)$, 투과선속(J)과 총여과부피$(V_T)$ 측면에서 고찰하였다. 광촉매 코팅 구의 농도가 감소할수록 $R_f$는 증가하고 J는 감소하였다. 광촉매 코팅 구의 농도 40 g/L 에서 $V_T$가 8.85 L로 가장 높았다. FT 변화 실험에서는 FT가 감소할수록, $R_f$는 감소하고 J는 증가하였다. 한편, BT 변화 실험에서는 BT가 증가할수록, $R_f$는 감소하고 J는 증가하였다. 또한, NBF(no back-flushing)에서 급격한 막오염에 의한 분리막 기공의 감소로 탁도 및 용존유기물($UV_{254}$ 흡광도)이 효과적으로 제거되었기 때문에, 탁도 및 용존유기물의 처리효율이 NBF 조건에서 가장 높았다. 한편, 광촉매 코팅 구의 세척 효과로 FT가 감소할수록, BT가 증가할수록 탁도 및 용존유기물의 처리효율은 증가하였다.

• 상하수도학회지
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• 제18권2호
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• pp.242-246
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• 2004

Dissolved air flotation (DAF) is an effective solid/liquid separation process for low density particles, such as algal flocs, humus materials and clay particles produced from low turbidity water. The fraction of humic substances for natural organic matters (NOMs) are considered problematic in water because it can readily react with chlorine to form harmful by-products (trihalomethanes) and can be exposed to undesirable color, tastes and odors in drinking water. A broad class of NOMs includes fulvic acid, humic acid and humin. This paper will discuss the results from a study that performed with a DAF pump process using synthetic wastewater contained humic substance. Batch jar tests were performed to evaluate coagulant dose and recycle ratio on flotation efficiency.

• 환경위생공학
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• 제16권3호
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• pp.34-41
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• 2001

It is well known that bioassay on the low organic matters in water have developed from the two methods. One is assimilable organic carbon(AOC) that makes use of the maximum growth biomass of the pure strains for the standard substrates, the other is biodegradable dissolved organic carbon(BDOC) that determines the fraction of dissolved organic carbon(DOC) available for microbial utilization. The purpose of this study was to upgrade the measurement method of BDOC in natural water or drinking water. BBOC was determined by means of the bacterial growth and the DOC decrease at the same time. The origin inoculums were used to the suspended bacteria from Han River water, The initial optimum biomass and incubation time for initial DOC were induced by variation of nutrient repression and inoculums. The time reached to minimum DOC was selected as incubation time. The initial optimum biomass for Han river water was about 1000~5000 CFU/mL, respectively. In a sufficient biomass, suitable incubation time was about 3~5 day. It was indirectly calculated BDOC on maximum growth rate by measuring growth yield of indigenous bacteria. But it was difficult to adapt growth yield coefficient because of irregular bacterial growth. The measured 3 day BDOC was close to BDOC calculated with our proposed experimental equation between DOC and BDOC. It shows that the quantification of BDOC with this experimental equation can be used indirectly.

• 한국물환경학회지
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• 제37권5호
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• pp.355-362
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• 2021

This study investigated the fate of dissolved organic matter (DOM) in a water reclamation facility (WRF) in Korea. The WRF consists of coagulation, sedimentation, microfiltration, and reverse osmosis (RO) components. The production capacity of WRF is 90,000 m³/day. The reclaimed water is reused as industrial water. We also characterized DOM in raw, processed, and finished waters based on analysis of dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm (UVA₂₅₄), fluorescence excitation emission matrix (FEEM), and DOC fractions via liquid chromatography-organic carbon detection (LC-OCD). Based on the results of DOC, UVA₂₅₄, and FEEM analyses, neither the coagulation/sedimentation nor the microfiltration at the WRF effectively removed DOM. The RO process removed more than 94% of DOM. The raw water (i.e., secondary treated effluent obtained from a wastewater treatment plant) exhibited tryptophan-like peaks, which are a promising marker of wastewater, in the FEEM analysis. Coagulation and microfiltration failed to eliminate the wastewater marker, whereas RO completely removed it. The raw water also carried high levels (89.4%) of hydrophilic and low-molecular weight substances, which are difficult to remove via coagulation-sedimentation or microfiltration. Humic substance was a major component of the hydrophilic fractions. Based on the LC-OCD analysis, RO effectively removed the humic and polymeric materials from DOM.

• 한국습지학회지
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• 제14권4호
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• pp.629-635
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• 2012

본 연구는 부영양화 호소의 개선을 위하여 분말활성탄 공정을 적용하고 호소수 내의 용존 유기물과 인의 제거특성을 파악하고자 수행되었다. 용존 유기물의 제거특성은 부유물질의 제거특성과 다르며 응집제 주입량과 pH에 영향을 받음을 확인하였다. 용존 유기물은 분말활성탄에 의해 흡착으로 제거되며 응집과정에서 용존 유기물의 제거효율을 증가시킬 수 있었다. 응집침전공정의 인 제거 과정과 같은 화학침전과정에서 형성되는 용존성 착화합물과 콜로이드성 물질은 인의 제거효율을 저하시키는 요인이다. 분말활성탄의 주입으로 콜로이드성 물질과 용존성 착화합물을 흡착함으로써 인의 제거효율을 증가시킬 수 있었다. 또한 분말활성탄은 응집과정의 floc의 밀도를 증가시켜 침전속도를 높이고 고액분리 효율을 높일 수 있었다.

• 대한환경공학회지
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• 제30권9호
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• pp.893-899
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• 2008

본 연구에서는 낙엽과 토양에서 추출한 용존 자연유기물질(DOM)을 대상으로 생분해 과정 중 변화하는 분광특성과 pyrene 결합 반응성을 조사하였다. 유기물질 특성 변화 분석을 위해 용존 유기탄소(DOC), 용존 자연유기물질 내 방향족 탄소성분을 나타내는 고유흡광도(Specific UV absorbance: SUVA), synchronous 형광 스펙트럼과 유기탄소결합계수(pyrene organic carbon-normalized binding coefficient: K$_{oc}$) 분석을 실시하였다. 3주간의 배양기간 동안 낙엽 추출 DOM과 토양 DOM의 DOC는 각각 61%, 51% 감소하였다. 배양 전과 후의 분광특성을 비교해 보면 단백질/아미노산 계 형광특징(PLF)은 점차 감소된 반면 SUVA, 펄빅산계 형광 특징(FLF)과 휴믹산 계 형광 특징(HLF)은 점차 증가하였다. 이러한 자연유기물질의 분광특성 변화는 생분해 과정을 통해 휴믹화가 진행되며 자연유기물질 내 비방향족 생분해성 탄소성분이 단단한 구조의 방향족 탄소구조로 변화됨을 시사한다. SUVA 값과 유기오염물질과의 결합정도를 나타내는 K$_{oc}$ 값 사이에서는 시료의 종류와 상관없이 1차 상관관계(r = 0.97)를 보여 주어 생분해가 진행되는 동안 방향족 탄소구조 분포가 자연유기물질의 소수성 오염물질과의 결합 정도에 큰 영향을 미침을 보여주었다. 또한 형광특징 중 FLF와 HLF가 K$_{oc}$ 값과 높은 상관관계를 보였으며 자연유기물질의 기원에 따라 다른 상관관계식을 보여주었다. 본 연구를 통해 생분해가 진행되는 동안 자연유기물질 성분변화 및 소수성 유기오염물질의 거동 예측에 자연유기물질의 분광특성이 좋은 모니터링 지표로 사용될 수 있음을 보여 주었다.

• 한국물환경학회지
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• 제20권1호
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• pp.55-62
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• 2004

This study was carried out to investigate the formation of DBPs(Disinfection By-products) such as trihalomethane(THMs) and haloacetic acid(HAAs) by chlorination in raw water and finished water of Water Treatment Plant(WTP). The formation of THMs was increased with the increase of pH and reaction time. HAAs was found as a high formation at a pH 7 and low formation at pH 9. THMFP(Trihalomethane Formation Potential) was the highest formation potential in raw water of Pu-1 and the lowest in raw water of Pa-1. In case of HAAFP(Haloacetic acid formation potential), So-1 showed the highest value, while Pa-1 showed the lowest value. It was investigated the relationship between HAAs and organic matters which were described as DOC(dissolved organic carbon) and $UV_{254}$. In both DOC and $UV_{254}$ versus HAAFP, Pu-1 showed the good correlation coefficients($r^2$) with 0.95 and 0.84, respectively. For three WTP investigated, DBPs(THMs + HAAs) was shown over the range of $42.00{\sim}49.36{\mu}g/L$. This result might be due to the different characteristic of organic matters in raw water and the difference of chlorine dosage for a water treatment.

• 한국물환경학회지
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• 제25권5호
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• pp.697-703
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• 2009

In this study, changes in the composition of dissolved organic carbon (DOC) were investigated using water samples collected at a downstream site of the Namhan River near the Lake Paldang ($N37^{\circ}24^{\prime}05.33^{{\prime}{\prime}}E127^{\circ}32^{\prime}25.01^{{\prime}{\prime}}$) during a heavy rain event from July 23 to July 28, 2008. The DOC concentrations varied from 1.68 to 3.18 mg/L with the maxium value at a peak of the river water level. Each DOC sample was fractionated into three compositions including hydrophilic (Hi), hydrophobic acid (HoA) and hydrophobic neutral (HoN) fractions. The results showed that HoA was most abundant fractions, constituting 47.2~56.5% of DOC. Refractory dissolved organic carbon (R-DOC) contents were also determined by measuring the DOC concentration after 28-day dark incubation of the samples. R-DOC content was in the range from 83 to 99% of DOC and it was significantly correlated with HoA contents (r = 0.91, p<0.005), while it did not exhibit such a good correlation with the fractions of Hi and HoN (p>0.02). Our results suggest that the HoA, which is associated with humic substances, may be a major composition of refractory organic matters in rivers during storm events.