• 한국환경보건학회지
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• 제35권1호
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• pp.64-70
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• 2009

The aims of this study is to examine the effects of the changes in HRT(Hydraulic Retention Time) and media charge in a water-mill, among other operation factors, on the nitrogen and phosphorus removal in order to use up-flow anaerobic reactors, anoxic reactors and water-mill aerobic reactors for sewage treatment. The extension of HRT improved the nitrogen removal efficiency, however the removal pattern was constant regardless of HRT. The removal of phosphorus was constant (80%-90%) regardless of the change in HRT. The removal rate with change in influx load varied such that at the OLR (Organic Load Rate) of 1-3 kg/d, the T-N removal efficiency was 80.7%-88.9% and the T-P removal efficiency was 82.9%-89.3% while at the NLR (Nitrogen Loading Rate) of 0.108-0.156 kg/d the removal efficiencies were 80.7-88.9% (T-N) and 82.9-89.3% (T-P). The analyses of the nitrogen and phosphorous removal characteristics with the C/N and C/P ratio showed that the mean T-N removal rate was 88% at the C/N ratio of 1.2-2.6, and that the mean T-P removal rate was 86% at the C/P ratio of 7.2-14.1. Also, the analysis of nitrogen and phosphorous removal characteristics were analyzed in relation to media charge. The comparison between with and without media charge in the water-mill showed that while the nitrogen removal efficiencies were 86-94% and 85-89% respectively, the difference of phosphorous removal efficiencies were between the two conditions was not significant, thus it suggested that the media charge has less effect on the removal efficiency of phosphorous compared to that of nitrogen.

• 한국환경과학회지
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• 제8권1호
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• pp.75-81
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• 1999

In recent years increasing production and disposal of wastewater have caused an accelerated eutrophication of receiving waters. Therefore, in order to alleviate the detrimental impact of wastewater discharge, there is an increasing demand for removing the main nutrients, nitrogen and phosphorus, as well as the organic content of the waste water prior to disposal. This is effectively achieved by extended conventional treatment technology. However, the working expenses and energy requirements of such advanced treatment systems are rather high. So in a sparsely populated rural community is required development of wastewater treatment system combined with the regional characteristics. In this study, the systems are planted with Reeds and Amaryllis In A.C and estimated purification potential of system. The results obtained are as follows. BOD removal rate is 20% in the early stage, the last removal rate is 35% in A.C process and is 65% in Amaryllis+A.C process and is 50% in Reed+A.C process. T-N removal rate by Amaryllis is average 2.6g/$m^3$ㆍd, T-N removal rate by Reed is average 1.76g/$m^3$ㆍd. T-P removal rate by Amaryllis is average 0.27g/$m^3$ㆍd, T-P removal rate by Reed is average 0.25g/$m^3$ㆍd. BOD removal rate constant with retention time is 1.4494(1/d), T-N removal rate constant is 0.5428(1/d), T-P removal rate constant is 0.5287(1/d).

• 멤브레인
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• 제20권3호
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• pp.241-248
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• 2010

$0.4\;{\mu}m$의 세공크기를 갖고 있는 평막이 침지된 연속회분식 반응기에서 유입 유기물 농도가 영양염류 제거에 미치는 영향을 조사하였다. 분리막의 여과성능과 영양염류 제거효과를 규명하기 위하여 유입 유기물의 농도를 200 mg/L (Run-1), 400 mg/L (Run-2) 및 800 mg/L (Run-3)로 연속적으로 변화시키면서 실험하였다. COD/N 및 COD/P의 비가 증가할수록 T-N 및 T-P의 제거율은 모두 증가하였다. Run-1, Run-2 및 Run-3에서 T-N의 평균 제거율은 각각 28.1, 32.6 및 90.4%이었으며, 투과수의 T-N 평균 농도는 각각 32.0, 30.0 및 4.3 mg/L 이었다. 또한 Run-1, Run-2 및 Run-3에서 T-P의 평균 제거율은 각각 13.6, 35.3 및 93.1%이었으며, 투과수의 T-P 평균 농도는 각각 3.11, 2.33 및 0.25 mg/L이었다.

• 상하수도학회지
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• 제26권1호
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• pp.131-139
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• 2012

Field experiment was performed from June 2010 to July 2011 to evaluate pollutants removal efficiency in the constructed wetland system for the treated wastewater and the river water. The wetland systems were constructed near Gyungan river. Two different systems with meandering shape were compared for seasonal base and operational period base. Several kinds of aquaculture are planted through the corridor of wetland system. Average removal rate of BOD, T-N and T-P for A system were 15.8%, 14.8% and 26.5%, respectively. Average removal rate of BOD, T-N and T-P for C system were 23.5%, 27.8% and 10.6%, respectively. The effluent from two wetland systems often exceeded effluent water quality standards for wastewater influent, however effluent water quality standards for river water. However, the wetland system can be useful to treat polluted river water and effluent from wastewater plant. Removal rate of pollutants in seasonal variation was the highest in summer for BOD and T-N, however the removal rates of T-P were higher in spring and autumn than in summer.

• 한국환경보건학회지
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• 제37권1호
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• pp.64-72
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• 2011

This study was performed to assess the removal efficiency on nitrogen, phosphorus and organic carbon in wastewater by spatial separation and internal recycling in a modified oxidation ditch process (modified OD). The performances of the modified OD were evaluated via laboratory-scale experiments. The process was operated at hydraulic retention times of 6-48 hours and solid retention times of 17-38 days. We found that organic carbon removal efficiency increased after the modified OD operation period. T-N removal efficiency remained stable; average T-N concentration of effluent was 8.02 mg/l after modified OD operation. In contrast, T-P concentration of effluent was over 1 mg/l. Nitrogen and phosphorus removal efficiency of modified OD at HRT 12 hr were 83.1% and 74.1%, respectively. Also, maximum efficiency was found at SRTs from 20 to 30 days. T-N removal efficiency was 83.1% at a C/N ratio from 3.0 to 3.5. However, T-N removal efficiency decreased at C/N ratios over 3.5. Also, T-P removal efficiency increased with HRT at C/P ratios in the same condition. Maximum efficiency was 74.1% at a C/P ratio from 25 to 28. T-N removal efficiency was 79.2% and T-P removal efficiency was 65.3% after M4 mode operation (added to the internal recycle line connected to the anoxic reactor). The modified OD with spatial separation and internal recycling developed in this study is, therefore, believed to be an improvement for solving problems in the nutrient removal technologies.

• 한국환경보건학회지
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• 제34권5호
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• pp.374-381
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• 2008

In this study, the factors affecting biological N and P removal using SND (simultaneous nitrification and denitrification) process were investigated and evaluated to examine the possibility of treating N and P through SND with NADH by surveying N and P traces in an aeration tank. Variations of $NH_4^+$-N+$NO_3^-$-N concentration were used to estimate the degree of SND in each point (P2, P3, P4, P5) of the aeration tank and these variations showed that denitrification efficiency in P2 (front zone), nitrification and denitrification efficiencies in P4 (middle zone) were 67%, 86% and 39%, respectively. When $PO_4^{-3}$-P concentration was analyzed in each point of the aeration tank, it was shown that $PO_4^{-3}$-P concentration coming into P2 was 1.25 mg/L, which increased to 2.22 mg/L by P release in P2 zone and then decreased to 0.74 mg/L by P uptake in P4. Consequently, we were able to estimate which high P removal efficiency observed in this study was caused by biological phosphorus removal. To determine the operating factors affecting effluent T-N, we analyzed the correlation among FN/M ratio, C/N ratio, Temp., SRT etc and these results showed that the correlation among FN/M ratio, C/N ratio and Temp was not high. However, the relationship of SRT and other parameters (effluent $NH_4^+$-N and effluent BOD) and the short SRT could have an affect on effluent $NH_4^+$-N and so effluent BOD could be increased. Thus, SRT operation should be controlled over 10 days. The results for analyzing the correlation between SRT and influent $NO_3^-$-N in order to investigate the operating factors affecting effluent T-P showed that T-P or $PO_4^{-3}$-P was not highly correlation with SRT, whereas $PO_4^{-3}$-P concentration increased along with increasing $NO_3^-$-N concentration into P2. Based on these results, we concluded, using regression analysis (R2=0.97), that effluent $PO_4^{-3}$-P concentration depends on $NO_3^-$-N concentration into P2.

• 한국습지학회지
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• 제11권3호
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• pp.37-47
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• 2009

본 연구지역은 전라남도에 위치한 고흥만 간척지 내 인공습지이며, 인공습지수와 주변 유입수의 수질특성을 파악하기 위해 2008년 3월 15일 및 2009년 1월 10일에 12개 지점에서 현장조사를 수행하였다. 수온, pH, DO, EC 및 salinity 항목은 현장측정 되었으며, 채수된 시료는 실내에서 TOC, Cl-, COD, TSS, T-P 및 T-N 성분을 분석하였다. 현장 관측된 5개 항목은 인공습지에 비해 유입지점들에서 높게 나타났으며, 이는 주변 농경 작지에서 유입되는 오염물질에 의한 것이다. 인공습지수와 유입수 내 농도비는 TOC 성분은 1월에, Cl 성분은 3 월에 더욱 높은 값을 보였다. COD 성분은 인공습지수에 대한 유입수의 농도비가 1.37배와 1.49배로서 유사하였다. 유입지점들에서 T-P와 T-N 성분의 평균값은 인공습지 내에서보다 3배 이상 높았으며, 인공습지의 자정능력에 의해 농도가 저감되었다. 본 연구지역의 인공습지에서는 유입수 내 Cl, T-P, T-N 성분의 정화효율이 높은 것으로 나타났다. Cl- 성분의 정화효율은 1차 관측 시 83%, 2차 관측 시 76% 이었으며, 이는 인공습지수에 의한 희석효과에 의한 것이다. T-P 성분의 정화효율은 67%(1차 관측)와 69%(2차 관측), T-N 성분은 100%(1차 관측)와 95%(2차 관측) 로서 매우 높았다. 본 연구에서 T-N의 정화효율이 비현실적으로 높은 것은 유입수의 양이 소량이어서 인공습지수 내에서는 질소 농도가 분석한계 이하로 나타났기 때문이다. 본 연구에서는 T-P 성분의 정화효율이 1월에, T-N 성분은 3월에 높게 나타나 생장기와 동절기의 영향에 의한 것으로 판단된다.

• 대한환경공학회지
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• 제34권5호
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• pp.295-303
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• 2012

본 연구는 DEPHANOX 공정내 분리조에 Al(III) ($Al_2(SO_4)_3{\cdot}17H_2O$)를 주입하여 유출수의 T-P 농도를 0.2 mg/L 이하로 유지하기 위한 주입량을 도출하고 Al(III) 첨가에 따른 질소 및 인 제거 효율을 평가하였다. 반응조 내에 Al(III)을 5, 10, 15 mg/L주입하여도 pH와 알칼리도 저감에 대한 영향은 나타나지 않았으며 반응조 내의 pH는 7~8 사이로 유지하였다. 응집제의 주입량이 증가할수록 유기물과 T-N 제거효율은 감소하였으나, T-P 제거효율은 주입량이 5, 10, 15 mg/L로 증가할수록 76.28, 84.02, 94.66% 증가하였다. Al(III)주입량 15 mg/L에서 유출수의 T-P 농도는 0.17 mg/L로 관찰되어 유출수의 T-P 농도를 0.2 mg/L 이하로 유지하기 위한 Al(III)의 주입량은 최소 15 mg/L 이상임을 확인하였다.

• 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.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2019년도 정기학술대회 발표논문집
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• pp.134-134
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• 2019

Utilization of organic waste as a renewable energy source is promising for sustainability and mitigation of climate change. Pyrolysis converts organic waste to gas, oil, and biochar by incomplete biomass combustion. Biochar is widely used as a soil conditioner and adsorbent. Biochar adsorbs/desorbs metals and ions depending on the soil environment and condition to act as a nutrient buffer in soils. Biochar is also regarded as a carbon storage by fixation of organic carbon. Phosphorus (P) and nitrogen (N) are strictly controlled in many wastewater treatment plants because it causes eutrophication in water bodies. P and N is removed by biological and chemical methods in wastewater treatment plants and transferred to sludge for disposal. On the other hand, P is an irreplaceable essential element for all living organisms and its resource (phosphate rock) is estimated about 100 years of economical mining. Therefore, P and N recovery from waste and wastewater is a critical issue for sustainable human society. For the purpose, intensive researches have been carried out to remove and recover P and N from waste and wastewater. Previous studies have shown that biochars can adsorb and desorbed phosphates implying that biochars could be a complementary fertilizer. However, most of the conventional biochar have limited capacity to adsorb phosphates and nitrate. Recent studies have focused on biochar impregnated with metal salts to improve phosphates and nitrate adsorption by synthesizing biochars with novel structures and surface properties. Metal salts and metal oxides have been used for the surface modification of biochars. If P removal is the only concern, P adsorption kinetics and capacity are the only important factors. If both of P and N removal and the application of recovery are concerned, however, P and N desorption characteristics and bioavailability are also critical factors to be considered. Most of the researches on impregnated biochars have focused on P removal efficiency and kinetics. In this study, coffee waste is thermally treated to produce biochar and it was impregnated with Mg/Al to enhance phosphates and nitrate adsorption/desorption and P bioavailability to increase its value as a fertilizer. Kinetics of phosphates and nitrate adsorption/desorption and bioavailability analysis were carried out to estimate its potential as a P and N removal adsorbent in wasewater and a fertilizer in soil.