• Environmental Engineering Research
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• 제12권4호
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• pp.148-154
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• 2007

The purpose of this research was to investigate the effects of low concentration of oxygen on reduction of perchlorate, especially low perchlorate influent concentrations in a biofilm reactor, as well as the effect of flow pattern in a biofilm reactor. Dissolved oxygen averaging 1 mg/L did not inhibit reduction of influent perchlorate from 23 to $426\;{\mu}g/L$ in the biofilm reactors when sufficient acetate was added, probably due to limitation of oxygen diffusion into the biofilm. Influent perchlorate ranging from 23 to $426\;{\mu}g/L$ was reduced to below detection level ($4\;{\mu}g/L$) in the presence of 1 mg/L dissolved oxygen (DO). Chloride was produced in a ratio of $0.37gCl^-/g{ClO_4}^-$ and $0.35gCl^-/g{ClO_4}^-$ in plug flow and recirculation biofilm reactor which is similar to stoichiometric amount ($0.36gCl^-/g{ClO_4}^-$) indicating complete perchlorate reduction at $426\;{\mu}g/L$ of ${ClO_4}^-$ feeding. At $23\;{\mu}g/L$L influent perchlorate, total biomass solids were 3.18 g and 2.81 g in the plug flow and recirculation biofilm reactors. The most probable number(MPN) analysis for perchlorate-reducing bacteria showed $10^4$ to $10^5\;cells/cm^2$ in both biofilm reactors throughout the experiments. The effluent perchlorate concentrations were not significantly different in the two different flow regimes, plug flow and recirculation biofilm reactors.

• 한국물환경학회지
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• 제28권1호
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• pp.38-49
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• 2012

In this study, we analyze statistical characteristics of influent water quality in Daejeon waste water treatment plant and apply a stochastic model for data generation. In the analysis, the influent water quality data from year 2003 to 2008, except for year 2006, are used. Among water quality variables, we find strong correlations between BOD and T-N; T-N and T-P; BOD and T-P; $COD_{Mn}$ and T-P; and BOD and $COD_{Mn}$. We also find that different water quality variables follow different theoretical probability distribution functions, which also depends on whether the seasonal cycle is removed. Finally, we generate the influent water quality data using the multi-season 1st Markov model (Thomas-Fiering model). With model parameters calibrated for the period 2003~2005, the generated data for 2007~2008 are well compared with observed data showing good agreement in general. BOD and T-N are underestimated by the stochastic model. This is mainly due to the statistical difference in observed data itself between two periods of 2003~2005 and 2007~2008. Therefore, we expect the stochastic model can be applied with more confidence in the case that the data follows stationary pattern.

• Coupled systems mechanics
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• 제9권2호
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• pp.111-123
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• 2020

Wastewater treatment plants (WWTPs) with activated sludge system are widely used throughout the most common technologies in the world. Most treatment plants require optimization of certain treatment processes using dynamic modeling. A lot of examples of dynamic simulations require reliable data base of diurnal variation of the inflow and typical concentrations of parameters such as Chemical Oxygen Demand (COD), Total Kjeldahl Nitrogen (TKN), etc. Such detailed data are not available, which leads to problemsin the application of dynamic simulations. In many examples of plants, continuous flow measurements are only performed after the primary clarifier, whereas measurements from influent to the plant are missing, as is the case with the examples in this paper. In some cases, a simpler, faster and cheaper way can be applied to determine influent variations, such as the "HSG-Sim" method ("Hochschulgruppe Simulation"). "Hochschulgruppe Simulation" is a group of researchers from Germany, Austria, Switzerland, Luxembourg, Netherlands and Poland (see http://www.hsgsim.org). This paper presents a model for generating daily variations of inflow and concentration of municipal wastewater quality parameters, applied to several existing WWTPs in Bosnia and Herzegovina (B&H). The main goal of the applied method is to generate realistic influent data of the existing plants in B&H, in terms of flow and quality, without any prior comprehensive survey and measurements at the site. The examples of plants show the influence of overflow facilities on the dynamics of input flow and quality of wastewater, and a strong influence of the problems of the sewerage systems.

• 한국물환경학회지
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• 제21권2호
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• pp.141-146
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• 2005

The aim of this study is to quantify and characterize the dissolved organic carbon (DOC) from paddy fields and crop fields in Tottori, Japan. DOC and ultraviolet (UV) absorption were measured in the filtrated water of each sample. The DOC concentration and the SUVA (specific UV absorption) of biodegradation analysis samples were determined around 50 days after their incubation. In the Fukui paddy fields, DOC concentration varied seasonally from 1.1 to $10.1mg\;Cl^{-1}$, becoming higher during heavy runoffs in April, a non-agriculture period. Variations in DOC concentration did not always correspond to rainfall, though. The Obadake paddy fields showed a DOC concentration pattern similar to that of the Fukui paddy fields. The daily DOC discharge per area in the Fukui (up), Fukui (down), Obadake (south) and Obadake (north) paddy fields influent from paddy fields were 0.02, 0.0161, 0.0135 and $0.0027kg\;a^{-1}day^{-1}$, respectively. These differences resulted from differences in agricultural types and customs of farmers according to paddy fields and other kinds of fields. Also, the SUVAs [which are indirect means to evaluate humic substances (hydrophobic fractions)] of the studied influent waters from paddy fields were generally lower than those of the influent waters from crop fields. Nonbiodegradable DOC accounted for 50.2 - 98% and 46.8 - 85.5% of the total DOC in the paddy fields and in the crop fields, respectively.

• 대한환경공학회지
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• 제31권2호
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• pp.102-108
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• 2009

연속회분식반응기에서 측정되는 기초상용계측기의 프로파일은 공정 내에서 수행되는 유기오염물질 및 영양염류 제거반응의 진행 정도에 대한 정보를 제공할 수 있다. 특히 호기성 반응구간에 측정되는 pH나 DO, ORP의 변곡점 등의 정보를 이용한 반응 종료 감지는 널리 알려진 응용사례라고 할 수 있다. 그러나 이러한 정보들은 반응의 종료 여부에 대한 정보를 제공할 뿐, 현재 공정에 가해지는 부하에 대한 정보를 제공하지는 못한다. 본 논문에서는 운전자에게 공정 유입수 내의 호기적 반응을 요하는 부하, 즉 암모니아 부하 및 유기물 부하의 고/중/저에 관한 정보를 제공할 수 있는 기초상용계측기의 정보를 활용한 진단 알고리즘을 개발하였다. 본 알고리즘으로 인해, 연속회분식반응기를 운전할 시에 수시로 변화하는 유입수의 부하를 습식분석 없이 자동 계측기 프로파일로부터 얻어낼 수 있을 것으로 사료된다.

• 수산해양교육연구
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• 제28권3호
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• pp.746-759
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• 2016

In this study, we monitored the status of marine environment of olive flounder, Paralichythys olivaceus, culture ground in Jeju-do, Republic of Korea. It reported the consumption of raw olive flounder meat containing of Kudoa, Kudoa septempunctata, could induce vomitting and diarrhea in Japan. The Kudoa is a new mycosporean species, researchers found Kudoa from the muscles of olive flounder cultured at western Japan and imported from Jeju-do. We choose two Kudoa positive farms and two negative farms in the mid of concern about the relation between Kudoa and habitat. We found two marine invasive species at the water-pumping seabed at one of the Kudoa positive farm. The concentration of pH and DO at on-growing flounder farms showed the decreasing pattern along side the raceway (influent sea waters > on growing sea waters > outfluent sea waters). The TN and TP values increased gradually following to the raceway (influent sea waters < on growing sea waters < outfluent sea waters). The concentration of COD and SS were in the range of $0.100-2.581mg{\cdot}L^{-1}$, $1.00-12.70mg{\cdot}L^{-1}$, respectively. The calculated residence time was 4hr 32minutes at F1, 11hr 21minutes at F2, and 9hr 50minutes at F3, respectively. It was calculated same distance of 4 km away from effluent pipes. Although direct relation between Kudoa and marine environment could not define well based on this study result, the more studies on marine environmental stressors for olive flounder are required to conduct as a reliable method including socio-economic group and environmental group.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.254-257
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• 2002

The purposes of this research are to identify the source and to analyze the pathway of nitrate contamination in "cultural village", Jeungpyeong. In order to examine recharge processes and flow pattern that closely related to the influent of nitrate contaminant, the flow field was simulated and the oxygen and hydrogen stable isotopes were analyzed. The nitrogen isotope was used to delineate contaminant sources. The shallow groundwater was mainly composed of precipitation, but leakage of domestic water and sewage contributed to the recharge. Nitrate contaminants were possibly from the leakage of sewage and animal waste. The nitrate concentration decreased due to dilution by low concentration water.ion water.

• 대한환경공학회지
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• 제30권1호
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• pp.45-53
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• 2008

본 연구에서는 국내 한 정수장의 고도정수처리공정의 실험분석 자료를 바탕으로 정수장으로 유입되는 원수의 수질특성과 처리공정별 오염물질 제거효율의 변화특성을 연구하였고, 활성탄여과조의 역세척에 따른 BAC 내의 미생물 거동을 추적하였다. KMnO$_4$ 소비량 등 8$\sim$9개의 주요 항목을 중심으로 제거특성이 연구되었고, 활성탄여과조의 유입 유출수에 대하여 NH$_3$-N 등 4항목의 농도변화를 추적하였다. 역세척 전 후의 활성탄 시료의 SEM 사진을 촬영하였고, 미생물 생체량(HPC) 조사를 통해 활성탄 부착미생물의 존재를 확인하고자 하였다. 유입원수의 특성은 대부분의 조사항목이 일정한 농도범위로 유입되었고 그 중 계절적 일관성을 갖는 항목이 있었다. 공정별 제거효율 변화특성은 월별 일정한 유형을 갖는 것, 공정진행에 따라 지속적으로 제거되는 것, 오존접촉조에서 제거효율이 떨어지는 것 등으로 분류되었고, 현재 운전되고 있는 고도처리공정에서 제거되는 주요 대상오염물질을 구별할 수 있었다. NH$_3$-N의 농도변화 곡선으로 활성탄여과조 내에 미생물이 존재함을 예측하여 SEM 사진과 HPC 측정으로 이를 확인하였다.

• 대한환경공학회지
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• 제33권1호
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• pp.25-31
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• 2011

본 연구에서는 하수처리공정의 유출 수질을 안정적인 유지하기 위하여, 유입수 패턴을 이용한 모델 기반 $NH_4-N$ 예측 제어 알고리즘을 개발하고 $A^2/O$ 공정을 대상으로 적용 및 평가하였다. 평가에 사용된 자료는 B 시 S 하수처리장에 위치한 pilot 규모의 $A^2/O$ 공정 운전자료를 사용하였다. 생물학적 반응조를 모사하기 위해 수정된 ASM3+bio-P 모델(Lee, 2003)을 사용하였고, 침전조 농도 거동 모사를 위해 일차원 이중 지수 함수 모델(Takacs et al., 1991)을 사용하였다. 유입수 패턴을 이용하여 하루 뒤 유출수 $NH_4-N$ 농도를 예측하고, 사전 작성된 $NH_4-N$ 제어 schedule을 사용하여 pilot plant의 호기조 DO를 조절하는 제어 로직을 적용하였다. 제어 적용성을 평가하기 위해 제어를 적용하지 않은 경우와 적용한 경우를 비교하였고, 계절적 영향을 알아보기 위해 여름철과 겨울철에 $NH_4-N$ 제어 schedule을 적용한 실험을 하였다. 여름철 및 겨울철 모두 제어를 적용하지 않은 경우 수질기준을 초과하는 사례가 발생하였지만, 제어를 적용한 경우 목표수질 이내의 안정적인 유출수질이 방출됨을 확인하였다. 제어를 적용하지 않은 경우에 비교해서, 예측 제어를 적용한 경우에는 송풍기의 RPM이 약 9.1% 증가하였고, 유출수의 $NH_4-N$ 농도는 약 45.2% 감소하였다. 이를 통해 본 연구에서 개발된 유출수 $NH_4-N$ 예측 제어 알고리즘 적용으로 인한 운영비용 증가 대비 수질 개선 효과가 크게 나타났기 때문에, 안정적인 유출수 확보를 위한 측면에서 효율적인 제어기법으로 판단된다.

• 상하수도학회지
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• 제18권4호
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• pp.500-507
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• 2004

This study was conducted to evaluate the equity of the flow distribution from rapid mixing basin to the flocculation basins. Also, several types of inlet structures of the open channel affecting the flow pattern and distribution trend were studied using Computational Fluid Dynamics (CFD) simulation. For investigating the factual phenomena in distribution channel, we selected a certain domestic water treatment plant with capacity of $361,000m^3/d$. From the measurements of flow discharge, it is investigated that this existing inlet geometry resulted in significant inequitable distribution. The both largest deviations in the basins and rows were over 10%. In order to reduce the these deviation, this study suggested installing a baffle against the influent, and showed the effectiveness which the largest deviation was less than 3%. Also, it was concluded that the existing design method of open channel could be improved by three-dimensional hydrodynamic analysis for optimizing the even flow.