• Advances in environmental research
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• 제4권4호
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• pp.263-271
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• 2015

In this study, the effect of initial nitrate loading on nitrate removal and byproduct selectivity was evaluated in a continuous system. Nitrate removal decreased from 100% to 25% with the increase in nitrate loading from 10 to $300mg/L\;NO_3-N$. Ammonium selectivity decreased and nitrite selectivity increased, while nitrogen selectivity showed a peak shape in the same range of nitrate loading. The nitrate removal was enhanced at low catalyst to nitrate ratios and 100% nitrate removal was achieved at catalyst to nitrate ratio of ${\geq}33mg\;catalyst/mg\;NO_3-N$. Maximum nitrogen selectivity (47%) was observed at $66mg\;catalyst/mg\;NO_3-N$, showing that continuous Cu-Pd-NZVI system has a maximum removal capacity of 37 mg $NO_3{^-}-N/g_{catalyst}/h$. The results from this study emphasize that nitrate reduction in a bimetallic catalytic system could be sensitive to changes in optimized regimes.

• Carbon letters
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• 제11권2호
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• pp.112-116
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• 2010

The objective of this study was to evaluate the possibility of simultaneous removal of ammonium, nitrate and phosphorus in water using the zeocarbon. In this study, the surface of zeocarbon was modified by acid because of difficulty in application of water treatment. After surface modification, the strength was enhanced about 62% higher than that of original one. The removal efficiency of ammonium and nitrate using the modified zeocarbon was about 47% and 32%, respectively and were higher than that of zeocarbon. In batch type experiment on the simultaneous removal of ammonium, nitrate and phosphorus, the presence of phosphorus did not have influence on nitrogen removal efficiency. Concomitantly, removal efficiency of phosphorus was obtained was about 35%. This indicates that the surface modified zeocarbon can be applied for simultaneous removal of nitrogen and phosphorus. Consequently, our results could be used as basic data to design of one-stage nitrogen/phosphorus simultaneous removal system.

• 청정기술
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• 제15권4호
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• pp.280-286
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• 2009

고농도의 질산성 질소를 함유하는 폐수의 처리에 전기투석법의 적용 가능성을 평가하기 위하여 전기투석 공정의 운전인자 중 유입농도, 운전전압, 그리고 유속이 질산성 질소의 제거효율에 미치는 영향을 실험적으로 평가하였다. 한계전류밀도는 유입농도와 유입유속이 증가함에 따라 선형적으로 증가하였다. 유입농도와 목표농도에 도달하는 시간은 직선적으로 비례관계를 보였고, 농축액의 초기농도가 제거속도에 미치는 영향은 거의 없었다. 저속에서 유입유속의 증가는 제거속도를 증가시켰지만, 일정속도 이상에서는 제거속도에 미치는 영향이 미미하였다. 운전전압의 증가에 따라 제거속도는 증가하였지만 그 증가속도는 점차 저하되었다. 본 연구에 사용된 전기투석모듈에서 고농도의 질산성 질소를 제거하는 최적 운전조건으로 유입유속 1.6 L/min, 한계전류밀도의 80~90%의 해당하는 운전전압이 권장된다.

• 한국환경과학회지
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• 제18권3호
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• pp.325-331
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• 2009

This study was aimed to behaviour of organics and nitrogen on the upflow anaerobic reactor when a acid fermenter is added. Up flow anaerobic reactor (UAR) reaction will result which operates, COD removal efficiencies of reactor with nitrate loading rate 0.11, 0.66g/L/d were over 77%, but one with 1.0g/L/d was 73.5%. Especially, on NLR 0.11g/L/d, COD removal was 77% and nitrate removal efficiency was 93% simultaneously. The other side upflow anaerobic reactor and acid fermenter (UAR+AF) reaction will result witch operates, COD removal efficiencies of reactor with nitrate loading rate 0.11, 0.66g/L/d were over 85%, but one with 1.0g/L/d was 80%. Especially, on NLR 0.11g/L/d, COD removal was 85% and nitrate removal efficiency was 98% simultaneously. Also, without in reaction condition increase of influent nitrate concentration resulted in the linear decrease of nitrate removal efficiency and nitrate removal efficiency at influent nitrate-nitrogen 800mg/L was 50%. Alkalinity was increased theoretically by denitrification at low nitrate-N concentration, however, it was not increased theoretically at high nitrate-No 40% nitrate-N of UAR was denitrified until 70% height of reactor and 90% nitrate-N of UAR+AF was denitrified until 30% height of reactor Upflow anaerobic reactor was to occur accumulate acid, which TVA/Alkalinity is 0.3$\sim$0.47. Increase of NLR resulted increase of effluent alkalinity and TVA production

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.107-110
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• 2003

Reduction of nitrate by zero valent iron (Fe$^{0}$ ) has been previously studied, but the proper treatment for the by-product of ammonium has not been reported. However, in terms of nitrogen contamination, ammonium may be regarded as another form of nitrogen contaminants since it can be oxidized to nitrate again under aerobic conditions. This study is focused on simultaneous removal of nitrate and its by-product of ammonium, with the ZanF (Zeolite anchored Fe), a product derived from zeolite modified by Fe(II) chloride followed by reduction with sodium borohydride. Batch experiments were performed without buffer at two different pH condition with ZanF, iron filing, Fe(II)-sorbed zeolite, and pure zeolite to estimate the nitrate reduction and the ammonium production. At higher pH, removal rate of nitrate was reduced in both ZanF and iron filings. ZnF removed 60 % of nitrate at initial pH of 3.3 with no production of ammonium, while iron filing showed equivalent production of ammonium to the reduced amount of nitrate. In terms of nitrogen contamination, ZanF removed about 60 % and 40 % at initial pH of 3.3 and 6, respectively, while iron filing presented negligible removal against total nitrogen including nitrate and ammonium.

• 상하수도학회지
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• 제26권4호
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• pp.579-589
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• 2012

To reduce extensive energy costs of the internal recycling for the purpose of denitrification in the advanced wastewater treatment, a post-treatment process using an electro-coagulation to treat nitrate in the secondary effluents is evaluated in this study. Removals of phosphorus and organics in the secondary effluents by the electro-coagulation were also evaluated to propose an alternative advanced wastewatert treatment process. A series of experiments of the electro-coagulation were carried out with the following 4 different samples: synthetic solution containing nitrate only, synthetic solution containing nitrate as well as phosphorus, secondary effluents from activated sludge cultivated in laboratory, and secondary effluents from real wastewater treatment plants. Removals of nitrate and phosphorus in the synthetic solution were 30 and 97 % respectively, which verified the feasibility of the process. Removals of nitrate, phosphorus and COD in the secondary effluents from the cultivated sludge in laboratory were 49, 90 and 19 % respectively. Removal efficiency of the total nitrogen, nitrrate, phosphorus and COD in the secondary effluent from real wastewater treatment plant were 50, 61, 98 and 80 % respectively. The removal of the total nitrogen was less than the nitrate as expected, which is due to the formation of ammonia nitrogen in the cathode. But the proposed scheme could be an energy saving and alternative process for the advanced wastewater treatment if further studies for the process optimization are carried out.

• 한국물환경학회지
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• 제31권5호
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• pp.556-562
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• 2015

In order to remove the organic substances and the nitrate-nitrogen contained in wastewater, some researchers have studied the simultaneous removal of organics and nitrogen by using different biocathode microbial fuel cells (MFCs). The operating conditions for removing the contaminants in the MFCs are the external resistances, HRTs, the concentration of the influent wastewater, and other factors. This study aimed to determine the effect of the external resistors and organic loading rates, from the changing HRT, on the removal of the organics and nitrogen and on the production of electric power using the Denitrification Biocathode - Microbial Fuel Cell (DNB-MFC). As regards the results of the study, the removal efficiencies of $SCOD_{Cr}$ did not show any difference, but the nitrate-nitrogen removal efficiencies were increased by decreasing the external resistance. The maximum denitrification rate achieved was $129.2{\pm}13.54g\;NO_3{^-}-N/m^3/d$ in the external resistance $1{\Omega}$, and the maximum power density was $3,279mW/m^3$ in $10{\Omega}$. When the DNB-MFC was operated with increasing influent organic and nitrate loading by reducing the HRTs, the $NO_3{^-}-N$ removal efficiencies were increased linearly, and the maximum nitrate removal rate was $1,586g\;NO^3{^-}-N/m^3/d$ at HRT 0.6 h.

• 한국응용과학기술학회지
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• 제33권4호
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• pp.795-801
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• 2016

본 연구는 응집제로 calcium alginate를 이용한 질산성 질소 처리에 관한 연구이다. 질산성 질소를 제거하기 위한 방법으로는 역삼투법, 이온교환수지법, 전기투석법, 생물학적 방법 등이 있지만 본 연구에서는 응집 침전시키는 방법으로서 질산성 질소를 처리하고자 하였다. 응집제로 이용한 calcium alginate가 킬레이트 결합을 형성하여 질산성 질소를 응집 침전시킬 것으로 예상하고, 응집제의 성분, 응집 반응시간, 응집제의 몰비, 응집제의 주입율에 따라 질산성 질소가 제거되는 경향을 보았다. 또한 FE-SEM과 EDS(Energy Dispersive X-Ray Spectrometer)를 통하여 응집반응 후 침전물의 구조 및 구성성분비를 분석함으로써 질산성 질소가 Calcium-nitro-alginate 형태로 제거되는지를 확인하였다. 그 결과 반응시간은 60분, 응집제의 몰비는 1:1일 때, 응집제의 주입율은 합성폐수의 2 %일 때 질산성 질소의 제거율이 최대 56.7 %로 나타났다.

• 상하수도학회지
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• 제22권3호
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• pp.307-314
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• 2008

In this study, the effects of applied voltage, solution pH and coexistence of other ions such as sulfate ion (${SO_4}^{2-}$) and chloride ion ($Cl^-$) were investigated on the removal of nitrate-nitrogen ($NO_3{^-}-N$) from ground water by electrodialysis. The examined operating conditions were evaluated for optimizing the removal efficiency of $NO_3{^-}-N$. Real ground water samples taken from a rural area of Yongin city and artificial ones with components similar to the real ground water were tested for the study, which contained $NO_3{^-}-N$ concentration of 17mg/L that exceeds current drinking water quality standard of 10 mg/L. The increase in the removal rate of $NO_3{^-}-N$ was observed as the applied voltage increased from 5V to 30V, while no significant increase in the removal rate appeared at the applied voltage beyond 20V during a given operating time. The removal rate appeared to get lower at both acidic and basic condition, compared to neutral pH. Coexistence of of ${SO_4}^{2-}$and $Cl^-$ demanded much longer operating time to achieve a given removal rate or to meet a certain level of treated water concentration. When nitrate ion was combined with ${SO_4}^{2-}$and $Cl^-$, the removal rate was reduced by 4.29% and 10.83%, respectively.

• 유기물자원화
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• 제24권1호
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• pp.59-63
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• 2016

본 연구는 제올라이트를 이용한 수중의 암모니아성질소 및 질산성질소 제거특성을 알아보고자 수중의 암모니아성질소 및 질산성질소의 흡착제거에 대한 흡착변화를 조사하였다. 연구결과 암모니아성질소 흡착제거에 대한 제올라이트의 최대흡착량은 120mg/g(암모니아성질소 / 제올라이트 무게)임을 알 수 있었고, 암모니아성 및 질산성질소의 흡착에 대해 Freundlich식과 Langmuir식을 비교해 보았을 때 Langmuir 등온흡착식에 더 일치함을 알 수 있었다. 이는 제올라이트가 피흡착제와 이온교환 및 단층흡착함을 의미한다. 또한, pH 변화에 따른 암모니아성질소의 처리효율은 pH 7 > pH 5 > pH 9 > pH 3 순임을 알 수 있었으며, 제올라이트가 암모니아성질소 인공폐수의 pH를 상승시킴을 알 수 있었다.