• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.1
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• pp.59-63
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• 2016

The objective of this study lies in identifying the applicability of zeolite for the removal of wastewater ammonium and nitrate nitrogens. To this end, the author tracked adsorption variations as seen with the adsorption removal of wastewater ammonium and nitrate nitrogens. As a result, it was indicated that the maximum adsorption of zeolite acting on the adsorption removal of ammonium nitrogen would reach 120mg/g (weight of ammonium nitrogen divided by that of zeolite), and that Langmuir adsorption isotherm explained the adsorption of ammonium and nitrate nitrogens better than Freundlich adsorption isotherm. This means that zeolite makes ion exchanges with adsorbate for unilayer adsorption. It was also indicated that the removal efficiency of ammonium nitrogen with varying pH would be higher in the order of pH7 > pH5 > pH9 > pH3.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1B
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• pp.105-109
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• 2009

It is a well known fact that baseflow discharge of rainfall runoff impacts on water quality of surface water significantly. In this paper, impacts of nitrate discharged as base flow on stream water quality were studied by using a software, PULSE from USGS to calculate monthly ground water discharge from hydrograph. We used water quality and flow rate data for Ghapcehon2 site in Daejeon city for year 2005 as well as ground water quality data in the watershed acquired from government agencies. Agricultural and forestry land use are dominant for upstream of Ghapcheon2 in the watershed. Base flow contributes about 85~95% of stream flows during spring and fall while 25~38% of stream flow was induced by base flow during summer and winter. Monthly nitrate loading discharged as base flow for Ghapcheon2 was estimated by using averaged nitrate concentration of groundwater in the watershed. Nitrate loading induced by base flow at Ghapcheon2 was estimated as 5.4 ton of $NO_{3}{^-}-N/km^{2}$, which is about 60% of nitrate loading of surface water, 9.2 ton of $NO_{3}{^-}-N/km^{2}$. Seasonal variation of nitrate concentration of base flow was estimated by dividing monthly nitrate loading by monthly base flow discharge. Nitrate concentration of groundwater was increasing from rainy season. From this study, it can be understood that ground water quality monitoring is important for the proper manage of surface water quality.

• Journal of Soil and Groundwater Environment
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• v.10 no.2
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• pp.20-27
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• 2005

The seasonal variation of water quality was studied in the Hwabongcheon. It runs though a small catchment where shallow groundwater was contaminated with $NO_3-N$ by intensive livestock facilities. A direct inflow of animal waste and incoming of contaminated groundwater affected its water quality. In the dry season, an important factor of water quality in the Hwabongcheon was direct inflow of animal waste. In the wet season, concentrations of $NO_3-N$ in the Hwabongcheon were elevated in spite of being diluted by precipitation. It could be explained by the effect of increased incoming of contaminated groundwater and showed by oxygen and hydrogen isotope values. $NO_3-N$ concentration in the Cheongmicheon was lower than that in the Hwabongcheon, so it increased next a junction. This effect was intense in wet season because $NO_3-N$ concentration in the Hwabongcheon was high.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.487-494
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• 2017

Since nitrate nitrogen is quite stable in aqueous solution, considerable skill is required to remove it. Low concentrations of nitrate nitrogen are easily removed, while high concentrations of nitrate nitrogen are difficult to remove. This study is to show that nitrate nitrogen in the form of gaseous nitrogen can be removed by using zinc ball with a diameter of about 3mm and to test the removal characteristics of nitrate nitrogen under various reaction conditions. As a result of this study, the treatment efficiency of nitrate nitrogen by continuous treatment with zinc ball was about 80%. However, there is a problem that the wastewater must be maintained in an acidic atmosphere of about pH 2, and the treated wastewater must be neutralized and discharged.

• 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.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.93-96
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• 2004

국내 대부분의 경작지를 차지하고 있는 논농사 지역에서의 질산성 질소의 자연저감을 고찰하기 위하여, 세 유형의 수조 환경을 조성하고 mesocosm 실험 연구를 수행하였다. 두개의 mesocosm에는 논토양을, 그리고 비교를 위하여 다른 하나에는 밭토양(황토)을 사용하였으며, 하나의 논토양 mesocosm과 밭토양(황토) mesocosm에는 벼를 재배하였다. 인위적으로 질산성 질소 성분을 용해한 지하수를 주입수로 사용하였으며, mesocosm을 통과한 물 시료를 41일 동안 12시간 또는 24시간 간격으로 채취하고 화학분석을 실시하였다. 실험 결과, 논토양에서는 실험 시작과 동시에 급격한 환원환경이 형성되었으며, 그 결과 탈질반응에 의해 질산성 질소의 농도가 현저히 저감되었다. 분석 자료의 해석 결과, 논토양 mesocosm에서는 유기물이, 밭토양 mesocosm에서는 철이온(Fe2+)이 질산성 질소의 탈질 반응에 중요한 역할을 수행하는 것으로 판단된다.

• 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.

• 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.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.851-856
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• 2010

A sulfur utilizing nitrite denitrification process could be placed after the shortcut biological nitrogen removal (SBNR) process. In this study, removal of nitrite using sulfur oxidizing denitrifier was characterized in batch tests with granular elemental sulfur as an electron donor and nitrite as an electro acceptor. At sufficient alkalinity, initial nitrite nitrogen concentration of 100 mg/L was almost completely reduced in the batch reactor within a incubation time of 22 h. Sulfate production with nitrite was 4.8 g ${SO_4}^{2-}/g$ ${NO_2}^-$-N, while with nitrate 13.5 g ${SO_4}^{2-}/g$ ${NO_3}^-$-N. Under the conditions of low alkalinity, nitrite removal was over 95% but 15 h of a lag phase was shown. For nitrate with low alkalinity, no denitrification occurred. Sulfate production was 2.6 g ${SO_4}^{2-}/g$ ${NO_2}^-$-N and alkalinity consumption was 1.2 g $CaCO_3/g$ ${NO_2}^-$. The concentration range of organics used in this experiment did not inhibit autotrophic denitrification at both low and high alkalinity. This kind of method may solve the problems of autotrophic nitrate denitrification, i.e. high sulfate production and alkalinity deficiency, to some extent.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.1013-1016
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• 2008

Nitrogen in the form of nitrate was electrochemically reduced with different cathode materials including Fe, Ni, Cu, and Zn. Zn cathode shows the greatest electrocatalytic activity on the transformation of nitrate ions into ammonia and the $NO_3^-$ removal efficiency has highest value at pH 8.5. Nitrogen in the form of nitrate was initially reduced into nitrite and sequentially, converted into nitrogen inside $NH_3$. Nitrogen in the form of ammonia was completely removed by the reaction with HOCl.