• 한국수산과학회지
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• 제33권4호
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• pp.367-372
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• 2000

회전원판식 해수 여과시스템에서 암모니아성 질소 부하율과 수리학적 부하량이 암모니아 제거율에 미치는 영향을 조사하기 위하여 일련의 실험을 실시하였다. 이 실험에서 회전원판 시스템은 폴리비닐필름 원판으로 여과조를 제작하였는데, 여과조의 표면적은 $12m^2$으로 용적은 $0.075m^3$이다. 회전원판식 시스템에서 암모니아성 질소부하율에 따른 암모니아 제거율을 조사하기 위하여 암모니아원으로 염화암모늄을 $10{\~}150 g$ 첨가하였다. 회전원판식 순환여과 사육시스템의 사육수에 암모니아원으로 염화암모늄을 $10{\~}150 g$ 투입하여 사육수의 암모니아 농도 (x: NH_4-N mg/l)에 따라 회전원판 여과조에서의 암모니아 제거에 필요한 시간 (y: hr)을 조사하였으며, 그 관계식은 다음과 같았다. $y=3.51+7.76 lnx (r^2=0.936)$사육수의 암모니아 농도가 2mg/l일 때 회전원판 여과사육 시스템에서 암모니아 제거에 소요되는 시간은 10시간이었으나, 암모니아 농도가 5와 16.5mg/l에서는 각각 16과 27시간이 소요되었다. 따라서 사육수의 암모니아 농도가 높아질수록 암모니아 제거에 소요되는 시간이 감소하는 경향을 나타내었다. 결론적으로 회전원판 여과 사육시스템의 최대 암모니아 제거율은 사육수의 암모니아 농도가 16.5 mg/l까지 상승함에 따라 증가함을 알 수 있었다.

• 한국환경복원기술학회지
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• 제14권1호
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• pp.121-132
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• 2011

Removal rates of $NO_3$-N and TN in the free-water surface wetland system during winter; December, January, February and March, spring and fall; April, May, October and November, and summer; Jun, July, August and September were investigated. The system was established on floodplain in the downstream reach of the Gwangju Stream in 2008. It measures 50 meters in length and 5.5 meters in width. Iris pseudacorus L. grown in pots for about two years were planted in the system. The water stream was funneled in by gravity and its effluent was discharged back in. Volumes and water quality of inflow and outflow were analyzed from December 2008 to November 2010. The inflow was averaged approximately 350 $m^3/day$ and hydraulic residence time was about 3 hours. Average influent and effluent $NO_3$-N concentration was 3.75 and 3.35 mg/L, respectively and $NO_3$-N retention was amounted to 10.6%. Influent and effluent TN concentration were averaged 4.93 and 4.30 mg/L, respectively and TN abatement reached to 12.9%. One-way ANOVA statistics claimed that the average removal rates of $NO_3$-N and TN during winter, spring and fall, and summer were not always the same (p<0.001). The t-Tests of three pairs among $NO_3$-N removal rates of winter, spring and fall, and summer illustrated that the removal rates of winter ($5.04{\pm}1.94$), spring and fall ($10.53{\pm}2.24$), and summer ($18.61{\pm}2.26$) were significantly different each others (p<0.001). Among TN removal rates, the three pairs of t-Tests of three seasons showed that the removal rates of winter ($5.21{\pm}2.51$), spring and fall ($11.71{\pm}3.12$), and summer ($21.53{\pm}4.86$) were significantly different from each others (p<0.001).

• 한국대기환경학회지
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• 제25권6호
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• pp.512-522
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• 2009

In this study, the removal efficiency of trimethylamine (TMA) and four reduced sulfur compounds (RSC) of $H_2S$, $CH_3SH$, DMS, and DMDS was investigated using deionized water as absorbent. To this end, two types of experiments were conducted which include: (1) by passing both RSC and TMA standard gases through water contained in an impinger system and (2) by passing TMA gases through a water spray system. In the former method, TMA standard gases were effectively removed (below detection limit) in all experiments. Likewise, minor fractions of some RSC ($CH_3SH$, DMS, and DMDS) were removed by water in line with theoretical expectations. In addition, the first type of our experiment was extended further to test some commercially available odor treatment products. The results of this test showed that removal efficiencies of RSC $(8.2\pm13.7\sim43.7\pm2.48%)$ were different significantly among 4 kinds of absorbent, while the removal of TMA was consistently good as water. In the second phase of experiment, removal efficiency of TMA was tested by passing its standard gas through a water spray system. The overall results of our study showed that the actual removal efficiency of odorants by water (as sorptive media) approached the values that can be predicted theoretically (by Henry's law).

• 한국물환경학회지
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• 제20권1호
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• pp.86-92
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• 2004

Lab-scale experiments have been carried out to investigate ammonia stripping with a modified spray tower for removing ammonia nitrogen from swine wastewater. The operating conditions such as initial pH, temperature, air flow, hole size of distributor determining the diameter of water drops, and influent solids concentration were closely examined focusing on removal efficiency of ammonia. As a result of the experiment, in order to achieve high rate of ammonia removal by the air stripping system, the air flow rate must be supplied at high rate with sufficiently high initial pH, temperature. The optimum operating condition to meet the residual ammonia concentration of 300 mg/L was the initial pH of 11.0 at $35^{\circ}C$ with the air flow rate of 20 L/min. It also showed that the smaller hole size is, the higher removal rate of ammonia is expected. However, when used a small sized distributor (2 mm), the flooding problem at the upper column occurred due to clogging of the hole. With regard to the influent solids concentration, it was showed that the lower concentration of solids, the higher removal rate of ammonia. The removal of particulate materials in influent led to improve the removal efficiency of ammonia, rather than to control the operating condition including initial pH, temperature, and air flow. The empirical correlation between KLa and operating parameters would be driven as, $K_{La}=(0.0003T-0.0047){\cdot}G^{0.3926}{\cdot}L^{-0.5169}{\cdot}C^{-0. 1849}$. The calculated $K_{La}$ from proposed formula can be used effectively to estimate the optimum reaction time and to calculate the volume of modified spray tower system.

• 상하수도학회지
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• 제26권1호
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• pp.107-113
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• 2012

Pollutants in aquaculture system effluent mostly originated from solid wastes including uneaten feed and excreta of cultured species. In this research, DAF(Dissolved Air Flotation) unit is suggested as an integrated solid control unit especially as a form of IIBG(Inline Injection Bubble Generation) process in aquaculture system. Solid removal performance of DAF unit was examined under various operation and salinity conditions with turbidity and suspended solid. Solid waste removal efficiencies were found to be affected by operation conditions including saturator pressure, recycle ratio, coagulant concentration. Solid removal efficiency was higher under higher saturator pressure and recycle ratio under which condition larger number of bubbles is generated. Coagulant is thought to have important role in creating bubble-particle aggregate by showing better removal efficiency with higher concentration. However higher saline water showed less effectiveness in removing solids by DAF(IIBG). Application of DAF(IIBG) process also showed additional effect in phosphate removal and DO(Dissolved Oxygen) supply. Phosphate existed in polluted water was removed up to 46% after treatment, which is thought to attribute to aluminium phosphate precipitation. And DO concentration was found to increase over 50% of initial saturation concentration after the injection of micro-bubbles. Through experiments on solid removal from aquaculture effluent, DAF(IIBG) process is estimated to be effective solid control method. This property can help aquaculture system being installed and operated simply and effectively.

• 한국물환경학회지
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• 제21권6호
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• pp.624-629
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• 2005

The purpose of this study is to investigate the performance of nitrogen removal using autotrophic microorganism in the Membrane-Attached Biofilm Reactor (MABR). The treatment system consists of an aerobic MABR (R1) for nitrification and an anaerobic MABR (R2) for hydrogenotrophic denitrification. Oxygen and hydrogen were supplied through the lumen of hollow-fiber membranes as electron acceptor and donor, respectively. In phase Ι, simultaneous organic carbon removal and nitrification were carried out successfully in R1. In phase II, to develop the biofilm on the hollow-fiber membrane surface and to acclimate the microbial community to autotrophic condition, R1 and R2 were operated independently. The MABRs, R1 and R2 were connected in series continuously in phase III and operated at HRT of 8 hr or 4 hr with $NH_4{^+}-N$ concentration of influent, from 150 to 200 mgN/L. The total nitrogen removal efficiency reached the maximum value of 99% at the volumetric nitrogen loading rate of $1.20kgN/m^3{\cdot}d$ in the combined MABR system with R1 and R2. The results in this study demonstrated that the combined MABR system could operate effectively for the removal of nitrogen in wastewater not containing organic materials and can be used stably as a high rate nitrogen removal technology.

• 한국지하수토양환경학회지:지하수토양환경
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• 제9권1호
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• pp.63-69
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• 2004

금속광산 일대의 비소오염 지중 복원기술로써 투수성 반응벽체의 흡착제로 철산화물인 적철석 피복 모래의 적용가능성을 평가했다. 이를 위해서 흡착곡선실험, 비소제거속도실험 및 컬럼내 비소 제거 실험을 통해서 철산화물 피복 모래에 의한 비소 3가와 비소 5가의 제거 효율 및 유동환경에서의 비소 제거능력에 대해 고찰하였다. 적철석 피복 모래는 1.0 mg/L 수준의 낮은 비소 농도에서 높은 흡착력을 보이는 선형 등온 흡착곡선을 보였다. 컬럼실험에서 높은 피복모래의 안은 비소제거효율을 높였으나, 비소 3가가 비소 5가보다 흡착력이 떨어지고 지하수의 유동적인 환경에서 비소의 물리적 확산 현상으로 흡착반응속도의 저하 때문에 제거양이 감소했다. 따라서, 유동적인 환경에서 피복모래의 상대적인 양, 비소화학종의 흡착력, 흡착반응속도가 제거 효율을 좌우했다.

• 농약과학회지
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• 제9권1호
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• pp.41-50
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• 2005

본 연구에서는 인삼성분의 조성을 변화시키지 않으면서 잔류농약만 제거시키는 방법을 pilot plant system에서 확립하고자 하였으며, 원래의 제조 공정에 따라 제조한 제품과 농약제거 공정을 적용하여 제조한 제품에서 155종의 잔류농약성분을 모니터링하였으며, 인삼성분을 비교 검토하였다. 농약제거공정을 거친 4가지의 공정은 control test에 비하여 잔류농약의 양이 많이 감소하였다. 즉, hexane을 이용한 공정에서 잔류농약이 제거되었고, 농약의 제거율을 높일 수 있는 가장 효율적인 방법은 헥산침지후 건조과정을 거친 공정으로 나타났다. 개발된 방법은 인삼농축액의 성분에는 영향을 미치지 않고 잔류농약만 89.1% 제거할 수 있었다.

• 상하수도학회지
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• 제34권5호
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• pp.345-356
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• 2020

The removal of organic carbon and nutrients (i.e. N and P) from wastewater is essential for the protection of the water environment. Especially, nitrogen compounds cause eutrophication in the water environment, resulting in bad water quality. Conventional nitrogen removal systems require high aeration costs and additional organic carbon. Microbial electrochemical system (MES) is a sustainable environmental system that treats wastewater and produces energy or valuable chemicals by using microbial electrochemical reaction. Innovative and cost-effective nitrogen removal is feasible by using MESs and increasing attention has been given to the MES development. In this review, recent trends of MESs for nitrogen removal and their mechanism were conclusively reviewed and future research outlooks were also introduced.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.11-24
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• 2003

This paper presents the results of laboratory investigation performed to study the role of different air sparging system parameters on the removal of benzene from saturated soils and groundwater. A series of one-dimensional experiments was conducted with predetermined contaminant concentrations and predetermined injected airflow rates and pressures to investigate the effect of soil type and the use of pulsed air injection on air sparging removal efficiency. On the basis of these studies, two-dimensional air sparging remediation systems were investigated to determine the effect of soil heterogeneity on the removal of benzene from three different homogeneous and heterogeneous soil profiles. This study demonstrated that the grain size of the soils affects the air sparging removal efficiency. Additionally, it was observed that pulsed air injection did not offer any appreciable enhancement to contaminant removal for the coarse sand; however, substantial reduction in system operating time was observed for fine sand. The 2-D experiments showed that air injected in coarse sand profiles traveled in channels within a parabolic zone. In well-graded sand the zone of influence was found to be wider due to high permeability and increased tortuosity of this soil type. The influence zone of heterogeneous soil (well-graded sand between coarse sand) showed the hybrid airflow patterns of the individual soil test. Overall, the mechanism of contaminant removal using air sparging from different soil conditions have been determined and discussed.