• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.459-462
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• 2003

충청북도 증평에 위치한 문화마을 인근의 19개 지하수 관측정에서 시료를 채취하여 질산성질소 농도와 $\delta$$^{15}$ N 값, 암모니아성질소 농도와 $\delta$$^{15}$ N 값을 정량하였다. 그 결과 질산성질소에 의한 심각한 오염은 관찰되지 않으며, 질산성질소내 $\delta$$^{15}$ N이 +9.4~+36.8%0의 범위를 갖는 것으로 보아 계분이나 생활하수 혹은 두 가지 이상의 오염원이 동시에 작용함을 나타낸다. 연구지역의 $^{15}$ N 부화지수($\varepsilon$)은 -6.697%0로 탈질에 의한 범위를 만족한다. 암모늄의 질산화가 주요한 반응기작일 경우에 나타나는 암모늄 농도 감소에 따른 $^{15}$ N의 부화는 관찰할 수 없다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.155-158
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• 2002

질산성질소 및 탁도로 오염된 지하수공에 대하여 환경성 복원을 위한 오염방지 시설을 시범 설치하였다. 지하수공에 대한 오염 정도를 조사한 결과 PS-1, CW-1, 그리고 CW-2 공이 질산성질소로 오염되어 먹는물 수질기준을 초과하였고, CW-3 공은 탁도가 먹는물 수질기준을 초과하였다. 오염원은 지하수공 개발시 수량 확보를 위하여 그라우팅을 제대로 하지 않은 불량시공으로 인한 오염된 지표수의 유입으로 기인되었다. 금번 연구는 오염된 지하수의 환경성 복원을 위한 것으로, 오염원과 지하수를 격리시켜 오염물질의 지하수 내 유입을 방지할 수 있도록 패커 그라우팅을 완벽하게 다시 실시하였으며, 오염방지시설을 설치하였다. 이 연구를 위하여 먼저 대수층의 분포 및 특성팍악, 지하수공내 지표수의 유입구간 규명, 지하수 오염원, 오염실태, 오염경로 등을 파악하였다 오염방지시설을 설치한 후, 설치 전,후의 질산성질소와 탁도의 함량을 비교하기 위하여 수질 분석을 실시하였다. PS-1의 경우, 오염방지시설 설치전의 질산성질소 함량은 16.1 mg/L 이었으나, 설치후에는 8.1 mg/L, 7.9 mg/L로써 설치전에 비하여 51% 감소되었으며, CW-1은 10.3 mg/L에서 6.3mg/L으로 39%, 그리고 CW-2는 14.9 mg/L에서 9.0 mg/L 으로 40% 감소되었다. CW-3 공의 탁도는 157 NTU에서 0.97 NTU로 완벽하게 복원되었다.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.1
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• pp.29-34
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• 2009

This study was performed under four operational conditions for nitrogen removal in metal finishing wastewater. The conditions include electrode gap, reducing agent, the recycling of treated wastewater in 1st step and the simultaneous treatment of nitrate and other materials. Result showed that the removal efficiency of $NO_3{^-}-N$ was highest at the electrode gap of 10 mm. As the electrode gap was shorter than 10 mm, the removal efficiency of $NO_3{^-}-N$ decreased due to increasing in concentration polarization on electrode. And, in case that the electrode gap was longer than 10 mm, the removal efficiency of $NO_3{^-}-N$ increased with an increase in energy consumption. Because hydrogen ions are consumed when nitrate is reduced, reducing reaction of nitrate was effected more in acid solution. As 1.2 excess amount of zinc was injected, the removal efficiency of $NO_3{^-}-N$ increased due to increasing in amount of reaction with nitrate. As the effluent from 1st step in the reactor was recycled into the 1st step, the removal efficiency of $NO_3{^-}-N$ increased. Because the zinc were detached from the cathode and concentration-polarization was decreased due to formation of turbulence in the reactor. The presence of $NH_4{^+}-N$ did not affect the removal efficiency of $NO_3{^-}-N$ but the addition of heavy metal decreased the removal efficiency of $NO_3{^-}-N$. As chlorine is enough in wastewater, the simultaneous treatment of nitrate and ammonia nitrogen may be possible. The problem that heavy metal decrease the removal efficiency of $NO_3{^-}-N$ may be solved by increasing current density or using front step of electrochemical process for heavy metal removal.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.246-251
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• 2003

전기분해법을 이용하여 수용액 중의 질산성 질소의 환원거동에 대한 연구를 통하여 수용액중의 질산 함량을 제어하는 연구를 수행하였다. 촉매전극을 채택한 복극전해조에서 30분의 조업에 질산 100ppm 이하의 저농도 용액은 70%, 300ppm 이상의 고농도의 경우는 90%까지 질소를 용이하게 제거할 수 있었다. 초기 질소농도가 증가하면서 한계전류밀도도 크게 증가하였으며, pH가 감소할수록 환원전류가 증가하였다. 그리고 수용액의 pH는 질소 환원반응기구에 큰 영향을 주는 것으로 판명되었으며, 산성에서는 질소형태로 중성 혹은 염기성에서는 암모니아 형태로 환원되는 것으로 추정된다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.1
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• pp.43-48
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• 2003

The effect of rare earth(RE) at three difference levels of nitrogen on the growth and nitrate content of chicory (Cichorium intybus L.) were studied in terms of leaf size, fresh and dry weight increase, and chlorophyll and nitrate content grown in plastic pots within glasshouse. Leaf size was enlarged as the level of nitrogen applied was high, and leaf within, length, and thickness of leaf were increased by RE treatment showing significant difference at high nitrogen(N+1) plot. As the level of nitrogen applied was high, as fresh and dry weight per plant was increased significantly(p<0.05), and sprinkling cabbage with RE increased fresh and dry matter yield to 2∼12, 4∼6.2% more, respectively. Dry matter content of Chinese cabbage was increased by RE sprinkling. At all levels of nitrogen fertilized chlorophyll contents were increased by RE treatment. As the level of nitrogen was high, as the content of chlorophyll was highly increased by RE. Nitrate was accumulated more at high level of nitrogen application, but nitrate was decreased by RE application, 40% decrease at very high nitrogen plot(N+2). RE stimulated the growth of chicory with high chlorophyll content, and showed the possibility producing high quality agricultural products low in nitrate content.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.387-393
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• 2011

We analyzed the particle size distributions of three commercially available Devarda's alloy (DA) products, tested the nitrate recoveries of each particle size category, and examined the amounts of DA required for 100% recovery by varying $NO_3$-N concentration from 0.5 to 10 mg. We observed that use of DA coarser than 200 mesh resulted in poor analytical recovery (<80%). While the tested alloys were considered to be fine enough (>90% of the particles were less than 100 mesh), the recovery dramatically declined from 80% to 10% in a high concentration range (4 to 10 mg N). Satisfactory recovery was obtained by increasing the amount of finer DA (less than 300 or 450 mesh). However, there was no quantitative relationship between the amount of fine DA and nitrate recovered. Generally, the amount of nitrate reduced per unit DA decreased as the recovery efficiency declined. These results suggest that a sufficient amount of DA must be determined based on particle size distribution, and that treatment of at least two levels of DA and comparison of the subsequent change in nitrate recovery is required for soils containing high levels of nitrate. In addition, further studies are encouraged to account for the observed stoichiometric dis-equivalence of recovered nitrate N per unit mass of DA.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.30-36
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• 2003

The effect of humic acid on the simultaneous removal of nitrate and phosphate was investigated in a micellar-enhanced ultrafiltration (MEUF). At the low molar ratio of cetylpyridinium chloride (CPC) to contaminants, the removal of nitrate was lower to 50％ by 100 ppm of humic acid due to the competition for binding on micelles. At the molar ratio higher than 3, however, the removal of nitrate was over 80％. Phosphate was removed over 80% at the molar ratio higher than 1. The CPC and humic acid were rejected over 99 ％ by UF membrane. The flux did not decrease by 100 ppm of humic acid but rather slightly increased since the humic acid adsorbed on the membrane made the membrane more hydrophilic. As a result, humic acid did not diminish the performance of MEUF in the simultaneous removal of nitrate and phosphate.

• Economic and Environmental Geology
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• v.37 no.6 s.169
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• pp.647-655
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• 2004

To identify the influential factors and their relative significance on spatial distribution of $NO_3-N$ in urban ground water, spatial analysis was conducted using GIS and statistical approaches in the Seongnae-Koduk watersheds, where rapid urbanization has been proceeded. Several factors were considered including land-use type, distance to sewage lines, the ratio of impervious surface, and the ratio of green area. The spatial distribution of $NO_3-N$ in the land-use types shows differences between urban and crop field possibly due to the sewage networks in urban areas and the agrochemical uses in crop field. Nitrate concentrations in ground water were decreased with the distance to sewage lines to approximately 60-75 m. Concentrations of nitrate and distances to sewage lines showed negative correlation, indicating that the nitrate contamination was induced from the sewage system and specially significant in urban areas. The negative correlation of the ratio of impervious surface to the nitrate concentration in urban areas also suggested that the source materials of nitrate are introduced from the surface. Consequently, in areas of urbanization processes, systematic management of past-and-present land-use types and sewage systems are the most significant factors in preventing ground water from nitrate contamination.

• KSBB Journal
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• v.24 no.3
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• pp.296-302
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• 2009

This paper was investigated the research regarding the effects of several factors such as initial ammonium nitrogen concentration, aeration rate. biomass amount and C/N ratio on nitrification process using synthetic wastewater and activated sludge obtained from wastewater treatment facility. As a result, in high ammonium nitrogen concentration above 100 mg/L, the pH of wastewater was dropped to pH 6.8. The increases of initial ammonium nitrogen concentration, aeration rate and initial biomass amount were linearly enhanced the removal rate of ammonium nitrogen. In the condition of C/N ratio of 0 to 3, high ammonium nitrogen removal rate was obtained.

• Clean Technology
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• v.15 no.3
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• pp.194-201
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• 2009

Reductive reactivity of zero-valent iron nanoparticles was investigated for removal of nitrate-nitrogen which is considered one of the major water pollutants. To elucidate the difference in reactivity between preparation methods, iron nanoparticles were synthesized respectively from microemulsion and aqueous solution of ferric ions. Iron nanoparticles prepared from microemulsion were deposited on aluminum by electrophoretic method, and their reaction kinetics was compared to that of the same nanoparticles suspended in aqueous batch reaction. With an approximation of pseudo-first-order reaction, rate constants for suspended nanoparticles prepared from microemulsion and dilute aqueous solution were $3.49{\times}10^{-2}min^{-1}$ and $1.40{\times}10^{-2}min^{-1}$, respectively. Iron nanoparticles supported on aluminum showed ca. 30% less reaction rate in comparison with the identical nanoparticles in suspended state. However, supported nanoparticles showed the superior effectiveness in terms of nitrate-nitrogen removal per zero-valent iron input especially when excess amounts of nitrates were present. Iron nanoparticles deposited on aluminum maintained reductive reactivity for more than 3 hours, and produced nitrogen gas as a final reduction product of nitrate-nitrogen.