• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1999년도 정기총회 및 춘계 공동 학술발표회
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• pp.149-156
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• 1999

In the United States (U.S.), the monitored natural attenuation (MNA) approach has been used as an alternative remedial option for organic and inorganic compounds retained in soil and dissolved in groundwater. The U.S. Environmental Protection Agency (EPA) defines the MNA as“in-situ naturally-occurring processes include biodegradation, diffusion, dilution, sorption, volatilization, and/or chemical and biochemical stabilization of contaminants and reduce contaminant toxicity, mobility or volume to the levels that are protective of human health and the environment”. The Department of Soil Environment. National Institute Environmental Research (NIER) is in the process for demonstrating the MNA approach as a potential remedial option for the BTEX contaminated site in Uiwang City. The project is charactering the research site in terms of the nature and extend of contamination, biological degradation rate, and geochemical and hydrological properties. The microbial-degradation rate and effectiveness of nutrient and redox supplements will be determined through laboratory batch and column tests. The geochemical process will be monitored for determining the concentration changes of chemical species involved in the electron transfer processes that include methanogenesis, sulfate and iron reduction, denitrification, and aerobic respiration. Through field works, critical soil and hydrogeologic parameters will be acquired to simulate the effects of dispersion, advection, sorption, and biodegradation on the fate and transport of the dissolved-phase BTEX plume using Bioplume III model. The objectives of this multi-years research project are (1) to evaluate the MNA approach using the BTEX contaminated site in Uiwang City, (2) to establish a standard protocol for future application of the approach, (3) to investigate applicability of the passive approach as a secondary treatment remedy after active treatments. In this presentation, the overall picture and philosophy behind the MNA approach will be reviewed. Detailed discussions of the site characterization/monitoring plans and risk-based decision-making processes for the demonstration site will be included.

• 멤브레인
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• 제15권1호
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• pp.70-83
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• 2005

폭기조를 간헐 폭기로 운전하여 호기/무산소(oxic/anoxic) 시간 비율과 무산소 조건에서 호기 조건으로의 전환시 공기세정이 투과플럭스 및 투과압력에 미치는 영향을 조사하였으며, 호기조건에서 무산소 조건으로 전환 시 펌프의 회전력에 의한 흡인압력이 투과플럭스와 투과 압력에 주는 영향을 조사하였다. 또한 긴 슬러지체류시간(SRT; Sludge Retention Time)과 고농도의 MLSS 유지시에 발생하는 미생물 대사산물이 분리막에 미치는 영향과 응집제를 투여하였을 때 분리막에 작용하는 플러스 효과에 대하여 조사하여 보았다. 호기/무산소(oxic/anoxic)의 시간비율에 따른 유기물 및 질소 제거효율을 조사해본 결과 폭기 40 비폭기 20분의 시간배분 조건에서 처리효율이 가장 양호하였으므로 호기/무산소(oxic/anoxic) 조건을 40/20분으로 한 조건(step-7)에서 약품주입 실험을 수행하였다. 액체 명반을 폭기조에 직접 투여할 경우 약품의 농도가 질산화 및 탈질 미생물에 많은 영향을 주는 것을 알 수 있었으며, MBR공정에서 인 1 mg/L를 제거하기 위해서는 약 0.7 mg/L의 액체명반이 필요한 것으로 확인되었다.

• 한국물환경학회지
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• 제22권3호
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• pp.546-556
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• 2006

The purpose of this study is to improve the polluted stream water quality by pilot-scale five different constructed wetlands (CWs). Cell 1 to 3 are newly designed 2SFCW (Surface-subsurface flow CW) with 1 to 3 flow shifters (FS) in the middle of the wetland system. Cell 4 and 5 are control CW (CCW), but Cell 5 is the same type as Cell 3. The FS, which converts the route of surface and subsurface flow between two wetlands connected in series, was able to enhance the treatability of TN via nitrification and denitrification and of SS due to filtration and sedimentation. The void fraction and dispersion number of Cell 1, 2 and 3 obtained from the RTD analysis were found to be 0.73 and 0.17, respectively. COD and TP removal efficiencies of Cell 1 to 3 were similar to that of Cell 4 and 5. SS removal efficiencies of Cell 1 to 3 and 5 with FS were 5-10% higher than that of Cell 4 without FS. TN removal efficiencies of Cell 1 to 3 were 3-14% higher than that of Cell 4 and 5. The average $R^2$ values of COD, SS, TN and TP obtained from nonlinear regression analysis were similar to the results of other researchers.

• 상하수도학회지
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• 제13권1호
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• pp.61-71
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• 1999

For a high-rate fermentation and recovery of organic acid, we have developed a new organic acid fermentation reactor with membrane filter, which is the most important part in the new advanced wastewater treatment system. The recovered organic acid is to be reused as an organic carbon source at denitrification process. Some experiments were conducted to compare the performance of acid fermentation at different SRTs, such as 5, 10, and 20 days. The total organic acid concentration produced during the runs was in the range of 2,100-2,900 (mgC/L). The conversion efficiency from substrate to organic acid reached to from 43% to 59%. The recovery rate of organic acid from substrate based on TOC was from 26% to 53%. Regardless of operational conditions, it has been able to maintain the membrane flux constantly, in the range of 0.4-0.46 ($m^3/m^2/day$). The transmembrane pressure drop was 0.2-0.3 (kg/cm) for 100 day's operation. The result of simulation is as follows. Organic removal efficiency of the new advanced treatment system is 95%. 73% of Nitrogen is removed. The removal efficiency of Phosphorus is 93%. By coqulation, soluble phosphorus is able to remove from the water treatment lines, which is impossible at conventional activated sludge system. The unit construction cost is 65000 (yen/m3) and it was 1.4 times than that of the standard activated sludge system. The unit operation cast is 7.7 ($yen/m^3/day$) and it was 1.3 times than that of the standard activated sludge system.

• 한국토양비료학회지
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• 제50권6호
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• pp.530-537
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• 2017

Composted animal manure added for improving soil quality and enhancing crop productivity can lead to greenhouse gas emissions such as nitrous oxide ($N_2O$) by processes of nitrification and denitrification. In addition, the amount of $N_2O$ emission from composted manure amended soils can vary greatly with composted manure type or different soil type. Therefore, the influence of cattle composted manure on $N_2O$ emissions was evaluated during growth of sweet potato (Ipomoea batatas). The treatments included control, conventional fertilization (CF), and CF + cattle composted manure (CCM) $10Mg\;ha^{-1}$ were applied in the spring. $N_2O$ emissions were significantly affected by composted manure and chemical fertilizer and the CCM had greater N2O emissions compared with other treatments. The majority of $N_2O$ emissions occurred shortly after composted manure and chemical fertilizer application compared with the rest of the growing seasons for all treatments. Also, $N_2O$ flux was associated with water-filled pore space (WFPS) at all treatments. On average of $N_2O$ emission accumulation, the CCM was 1.5 times greater than control treatment while there was no difference between CF and control.

• 한국물환경학회지
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• 제37권1호
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• pp.47-54
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• 2021

Aerobic granular sludge (AGS) can be classified as a type of self-immobilized microbial aggregates measuring more than 0.2 mm. It offers the option to simultaneously remove COD, N, and P that occur in different zones inside a granule. Also, AGS is characterized by high precipitability, treatability with high organic loading, and high tolerance to low temperature. In this study, a sequencing batch reactor inoculated with AGS (AGS-SBR) is a new advanced wastewater treatment process that was proven to grow AGS with integrated nutrient removal and low C/N ratio. A pilot plant, AGS-SBR with a capacity of 225 ㎥/d was installed at an S sewage treatment plant in Gyeonggi-do. The results of the operation showed that the water quality of the effluent indicated that the value of BOD5 was 1.5 mg/L, CODMn was 11.4 mg/L, SS was 6.2 mg/L, T-N was 13.2 mg/L, and T-P was 0.197 mg/L, and all of these values reliably satisfied an effluent standard (I Area). In winter, the T-N treatment efficiency at a lower temperature of less than 11℃ also showed reliability to meet the effluent standard of the I Area (20 mg/L or less). Analysis of microbial community in AGS showed a higher preponderance of beneficial microorganisms involved in denitrification and phosphorus accumulation compared with activated sludge. The power consumption and sludge disposal cost were reduced by 34.7% and 54.9%, respectively, compared to the domestic SBR type sewage treatment plant with a processing capacity of 1,000 ㎥/d or less.

• 한국기후변화학회지
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• 제8권3호
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• pp.231-237
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• 2017

In this study, the $N_2O$ emission factor of the facility was developed by measuring the kiln type pyrolysis melting facility. This used PAS (Photoacoustic Spectroscopy) method and measured the $N_2O$ emission concentration. From March 2016 to April 2016, it was measured over a total of two times and $N_2O$ concentrations were measured continuously for 24 hours using a 24 hour continuous measuring instrument (LSE-4405). The measured $N_2O$ emission concentration of the pyrolysis melting facility was 0.263 ppm on average and the emission concentration distribution in the range of 0.013~0.733 ppm was obtained. Therefore, the $N_2O$ emission factor of the kiln-type pyrolysis melting facility was estimated to be $0.829gN_2O/ton$-Waste. As a result of comparing the $N_2O$ emission factor of the thermal kiln type pyrolysis melting facility and the previous study, previous studies were about 18 times higher. It is estimated that this is due to the difference of furnace temperature, oxygen concentration and denitrification facilities. It is considered that the study of the emission factor of pyrolysis melting facility is an important factor in improving the credibility of greenhouse gas inventory in waste incineration sector.

• 한국물환경학회지
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• 제35권2호
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• pp.165-180
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• 2019

Water quality data of 81 lakes in Korea, 2013 ~ 2017 were analyzed. Most water quality parameters showed left-skewed distribution, while dissolved oxygen showed normal distribution. pH and dissolved oxygen showed a positive correlation with organic matter and nutrients, which appeared to be a nonsense correlation mediated by the algae. The ratio of $BOD_5$ and $COD_{Mn}$ to CBOD was 21 % and 52 % in the freshwater lakes, respectively. TOC concentration appeared to be underestimated by the UV digestion method, when salinity exceeds $700{\mu}S\;cm^{-1}$. In terms of nitrogen/phosphorus ratio, the limiting factor for algal growth seemed to be phosphorus in most of the lakes. Chlorophyll ${\alpha}$ increased acutely with decrease of N/P ratio. However, it seemed to be a nonsense correlation mediated by phosphorus concentration, since the N/P ratio depended on phosphorus. The N/P ratio of brackish lakes was lower than that of the freshwater, at the same concentration of phosphorus. It is worth examining denitrification that occurs, in bottom layer and sediment, during saline stratification. $Chl.{\alpha}$ concentration decreased in the form of a power function with increase of mean depth. The primary reason is that deep lakes are mainly at the less-disturbed upstream. However, it is necessary to investigate the effect of sediment, on water quality in shallow lakes. Light attenuation in the upper layer, was dominated by tripton (non-algal suspended solids) absorption/scattering (average relative contribution of 39 %), followed by CDOM (colored dissolved organic matter) (average 37 %) and $Chl.{\alpha}$ (average 21 %).

• 자원리싸이클링
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• 제29권6호
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• pp.114-124
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• 2020

시멘트 산업에서 질소산화물 배출은 중요한 문제로 인식되고 있으며 이를 저감하는 기술은 공정변경, 단계적 연소, 저 NOx 버너, SNCR, SCR로 나눌 수 있다. 이중 시멘트 산업에서 가장 많이 사용되고 있는 SNCR 운영만으로는 향후 강화될 배출허용기준을 만족시키기 어려울 것이 예상되며 SCR 등의 추가적인 장비 개선 및 기술 확보가 필요한 상황이다. 이에 따라 최근에는 국외를 중심으로 SNCR 및 SCR 동시 적용 기술, 분진 및 탈질 필터 기술과 NO 산화를 이용한 제거기술 등을 개발하고 있다.

• 한국환경과학회지
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• 제30권3호
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• pp.195-206
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• 2021

Contaminated marine sediment is a secondary pollution source in the coastal areas, which can result in increased nutrients concentrations in the overlying water. We analyzed the nutrients release characteristics into overlying water from sediments and the interaction among benthic circulation of nitrogen, phosphorus, iron, and sulfur were investigated in a preset sediment/water column. Profiles of pH, ORP, sulfur, iron, nitrogen, phosphorus pools were determined in the sediment and three different layers of overlying water. Variety types of sulfur in the sediments plays a significant role on nutrients transfer into overlying water. Dissimilatory nitrate reduction and various sulfur species interaction are predominantly embodied by the enhancing effects of sulfide on nitrogen reduction. Contaminant sediment take on high organic matter, which is decomposed by bacteria, as a result promote bacterial sulfate reduction and generate sulfide in the sediment. The sulfur and iron interactions had also influence on phosphorus cycling and released from sediment into overlying water may ensue over the dissolution of ferric iron intercede by iron-reducing bacteria. The nutrients release rate was calculated followed by release rate equation. The results showed that the sediments released large-scale quantity of ammonium nitrogen and phosphate, which are main inner source of overlying water pollution. A mechanical migration of key nutrients such as ammonia and inorganic phosphate was depicted numerically with Fick's diffusion law, which showed a fair agreement to most of the experimental data.