• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.5
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• pp.663-672
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• 2024

Nitrate contamination primarily results from agricultural activities and wastewater inputs, potentially leading to groundwater pollution. This study analyzed the reactive transport of nitrate in surface-groundwater interactions in the Gadeok-myeon, Cheongwon-gun, using integrated SWAT, MODFLOW, and RT3D models. The study used SWAT to simulate hydrological cycles, MODFLOW for groundwater flow analysis, and RT3D to model the reactive transport of nitrate. SWAT was used to estimate daily groundwater recharge and nitrate concentrations, which were then input into MODFLOW and RT3D models. The results showed that groundwater flow and reactive transport of nitrate were effectively simulated, providing insights into improving predictive models for groundwater and surface water interactions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.153-157
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• 2004

다양한 혐기성 조건에서 다환방향족탄화수소(PAHs)로 오염된 토양의 미생물 분해 연구를 수행하였다. 대표적인 다환방향족탄화수소인 phenanthrene과 fluorene을 토양과 물에 오염시켜서 약 100일 동안 저감정도를 관찰하였고, 실제 다환방향족탄화수소로 오염된 현장 토양을 이용 혐기성하에서 다환방향족탄화수소의 생분해 가능성을 확인하였다. 미생물 접종원은 혐기성 조건에서 다환방향족탄화수소에 노출시킨 슬러리가 사용되었다. 황산염 환원조건, 질산염 환원조건, 메탄생성조건 등의 다양한 혐기성 조건에서 실험을 수행한 결과, 메탄생성조건 > 질산염 환원조건 > 황산염 환원조건의 순서로 분해가 잘 일어났다. 또한 현장오염토양의 경우 34일간 처리 후 메탄생성조건에서 최대 72%의 분해율을 보였다.

• Agrochemical news magazine
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• v.17 no.6 s.135
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• pp.6-7
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• 1996

• Economic and Environmental Geology
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• v.41 no.4
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• pp.393-403
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• 2008

Hydrogeochemistry of groundwater was studied in order to identify the influence of cow manure, distributed to a farmland as organic fertilizer, on nitrate concentrations in shallow groundwater and its spatio-temporal variations. From monitoring wells, water levels were measured using automatic data loggers, and water samples collected and analyzed in Feb., April, June and Oct. 2007. The average electric conductivity and concentration of nitrate in the groundwater show the highest levels in April and decline in subsequent sampling times. Decreases in dissolved oxygen(DO) and nitrate concentrations from April to Oct. and corresponding increases in $HCO_3$ concentrations indicate denitrification processes by microorganisms. Spatial variation of nitrate concentration appeared to be affected by the redox conditions of groundwater controlled by geochemical reactions of Mn, Fe and DOC contents.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.3
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• pp.107-110
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• 1999

18 boreholes with nitrate contaminated were selected. Samples were collected 4 times between both 1995 and 1996. Stable nitrogen isotope ratio for them all was measured and the contribution to contamination from several sources like fertilizer, sewage, cropland. and landfill was analysed. Nitrogen source for 11 sampling sites of T-3, L-1. O-1∼O-4, F-2∼F-5, and G-2 considered to come from chemical fertilizer and its contribution was around 60% or more. T-4. T-5 were located downward the downtown, which were influenced bydomestic sewage and its contribution were 70.7% and 54.7%. Nitrate concentration of G-2 was 17.7 mg/L, among which 60.7% was estimated to come from landfill leachate. T-1 and T-2 were located in the small village, in which 42.2 and 43.4% of nitrogen was to come from domestic sewage but 52.8% and 56.0% were from fertilizer sprayed in the cropland. L-2 was near livestock by which it was estimated to be influenced, in which 59.9% of nitrogen was from cropland. F-1 was in the cropland, by which 50.0% was influenced and 49.5% was estimated from organic matter of animals.

• Economic and Environmental Geology
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• v.43 no.1
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• pp.43-52
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• 2010

The geochemical and nitrogen isotopic analyses for shallow groundwater of Ogcheon area were carried out to characterize the geochemical characteristics of the groundwater and to identify the source of nitrate. Groundwater shows a neutral pH to weakly alkalic condition with pH values ranging from 6.9 to 8.4. The average of EC, Eh and DO is $344.2\;{\mu}s/cm$, 195 mV, 4 mg/L, respectively. According to piper diagram, chemical composition of groundwater is dominantly characterized by Ca-$HCO_3$ type. On the other hand, groundwater type in the study area include Ca-Cl+$NO_3$ type that were highly influenced by agricultural activities. $NO_3$-N concentration of the collected samples(n=45) range from 12.4 to 34.2 mg/l. These data show that the $NO_3$-N concentration exceeds Korea Drinking Water Standard (10 mg/l). The $\delta^{15}N-NO_3$ values range from $2.7^{\circ}/_{\circ\circ}$ to $18.8^{\circ}/_{\circ\circ}$. The enrichments of heavy isotope in the groundwater indicate that major origin of nitrate pollution were associated with animal and human waste. Also the denitrification may have partly contributed as one of the sources of nitrogen.

• Journal of Soil and Groundwater Environment
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• v.14 no.3
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• pp.40-46
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• 2009

The applicability of a well-type autotrophic sulfur-oxidizing reactive barrier (L $\times$ W $\times$ D = $3m\;{\times}\;4\;m\;{\times}\;2\;m$) as a long-term treatment option for nitrate removal in groundwater was evaluated. Pilot-scale (L $\times$ W $\times$ D = $8m\;{\times}\;4\;m\;{\times}\;2\;m$) flow-tank experiments were conducted to examine remedial efficacy of the well-type reactive barrier. A total of 80 kg sulfur granules as an electron donor and Thiobacillus denitrificans as an active bacterial species were prepared. Thiobacillus denitrificans was successfully colonized on the surface of the sulfur granules and the microflora transformed nitrate with removal efficiency of ~12% (0.07 mM) for 11 days, ~24% (1.3 mM) for 18 days, ~45% (2.4 mM) for 32 days, and ~52% (2.8 mM) for 60 days. Sulfur granules attached to Thiobacillus denitrificans were used to construct the well-type reactive barrier comprising three discrete barriers installed at 1-m interval downstream. Average initial nitrate concentrations were 181 mg/L for the first 28 days and 281 mg/L for the next 14 days. For the 181 mg/L (2.9 mM) plume, nitrate concentrations decreased by ~2% (0.06 mM), ~9% (0.27 mM), and ~15% (0.44 mM) after $1^{st}$, $2^{nd}$, and $3^{rd}$ barriers, respectively. For the 281 mg/L (4.5 mM) plume, nitrate concentrations decreased by ~1% (0.02 mM), ~6% (0.27 mM), and ~8% (0.37 mM) after $1^{st}$, $2^{nd}$, and $3^{rd}$ barriers, respectively. Nitrate plume was flowed through the flow-tank for 49 days by supplying $1.24\;m^3/d$ of nitrate solution. During nitrate treatment, flow velocity (0.44 m/d), pH (6.7 to 8.3), and DO (0.9~2.8 mg/L) showed little variations. Incomplete destruction of nitrate plume was attributed to the lack of retention time, rarely transverse dispersion, and inhibiting the activity of denitrification enzymes caused by relatively high DO concentrations. For field applications, it should be considered increments of retention time, modification of well placements, and intrinsic DO concentration.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.05a
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• pp.1-3
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• 1997

질산염(NO$_3$)은 음전하를 띠고 있기 때문에 지하에서 제거되기 어려운 물질 중 하나이다. 특히, 매립지로부터 침출수로 유출될 경우 통제하기가 곤란하다. 본 연구에서는 제철폐기물로서 다량 발생하는 제강슬러지와 제강슬래그를 매립지 복토/차수재로 이용시 NO$_3$흡착 제거 가능성을 알아보기 위해 온도, pH, 초기농도를 변화시키는 회분식방법의 실험을 실시하였다. 온도와 PH는 낮을 때. 초기농도는 높을 때 높은 흡착제거 효율을 나타내었다.

• Journal of Environmental Impact Assessment
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• v.24 no.1
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• pp.87-98
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• 2015

Geochemical characteristics, water quality, $NO_3{^-}$ contamination and the origin of $NO_3{^-}$ were analyzed for the groundwater located at Ogcheon, Korea. The water qualities were weakly acidic to weakly alkalic and redox potentials indicated reduction condition. Compared to granitic rocks, metamorphic sedimentary rocks with intercalations of limestones and dolomites tended to be more effectively dissolved, resulting in higher pH and higher concentrations of dissolved ingredients. Contamination of heavy metals was not revealed. Geochemical reactions of carbonate rocks and influxes of artificial contamination ingredients seemed to simultaneously determine the geochemical characteristics and water qualities in the study area. From the results of ${\delta}^{15}N$ isotope analysis, the origin of $NO_3{^-}$ was estimated to be influenced dominantly by agricultural activities and human feces and urine.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.301-306
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• 2013

This research was conducted to investigate whether sequential anoxic/aerobic biofilm reactors and microfilteration (MF) membrane system can be used as a direct treatment for the removal of perchlorate and nitrate in groundwater. The biofilm process consisted of an anoxic first stage to remove perchlorate and nitrate and aerobic second stage to remove remaining acetate used as a carbon source for dissimilatory reduction of perchlorate and nitrate. In final stage, hollow fiber MF membrane was used to remove turbidity. In this research, perchlorate was reduced from the influent concentration of 102 ${\mu}/L$ to below the IC detection level (5 ${\mu}/L$) and nitrate was reduced from 61.8 mg/L (14 mg/L $NO_3$-N) to 4.4 mg/L (1 mg/L $NO_3$-N). Acetate used as a carbon source was consumed from 179 mg/L $CH_3COO-$ to 117 and 11 mg/L $CH_3COO^-$ in effluents from anoxic and aerobic biofilm reactors, respectively. Turbidity was reduced from 3.0 NTU to 1.5, 0.3, and 0.2 NTU in effluents from anoxic/aerobic biofilm reactors and MF membrane, respectively. It is expected that the sequential anoxic/aerobic biofilm reactors and MF membrane system can efficiently remove perchlorate and nitrate in surface water or groundwater.