• 한국환경과학회지
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• 제24권10호
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• pp.1253-1264
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• 2015

This study assessed the fertilizing value of struvite deposit recovered from swine wastewater in cultivating Chinese cabbage. Struvite deposit was compared with commercial fertilizers: complex, organic and compost to evaluate the fertilizing effect of struvite deposit. Laboratory pot test obviously presented that the struvite deposit more facilitated the growth of Chinese cabbage than organic and compost fertilizers even though complex fertilizer was the most effective in growing Chinese cabbage. It was revealed that the growth rate of Chinese cabbage was simultaneously controlled by phosphorus (P) and potassium (K). Also, the nutrients such as nitrogen (N), P, K, calcium (Ca) and magnesium (Mg) were abundantly observed in the vegetable tissue of struvite pot. Specifically, P was the most abundant component in the vegetable tissue of struvite pot. Meanwhile, the utilization of struvite as a fertilizer led to the lower accumulation of chromium ($Cr^{6+}$) than other pots, except for compost fertilizer pots, and no detection of cadmium (Cd), arsenic (As) and nickel (Ni) in the Chinese cabbage. The experimental results proved that the optimum struvite dosage for the cultivation of Chinese cabbage was 2.0 g struvite/kg soil. On the basis of these findings, it was concluded that the struvite deposits recovered from swine wastewater were effective as a multi-nutrient fertilizer for Chinese cabbage cultivation.

• Journal of Forest and Environmental Science
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• 제30권1호
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• pp.85-90
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• 2014

Dewaterability, one of the important properties of wastewater sludge, was investigated using a simple capillary suction time (CST) measurement method. CST and SRF have a very close co-relation. It was convinced that CST method was quite effective, and compensating the time-consuming SRF of conventional drainage measuring method. It turned out that one could use the results of CST to find optimum flocculants ratio to improve drainage in wastewater treatment for the tissue paper production at a mill. Since the optimum ratio of flocculants could be determined with the value of CST and COD removal efficiency could be improved with precise ratio of flocculants. Thus, using CST for determining the optimum ratio of flocculants could be economical by reducing the amount of flocculants. Dewaterability might be measured within several seconds using the values of CST in a precise way. The dewaterability could also be useful in investigating the optimum ratio of flocculants.

• Environmental Engineering Research
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• 제21권1호
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• pp.29-35
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• 2016

This study evaluated the fertilizing value of struvite deposit recovered from swine wastewater in cultivating lettuce. Struvite deposit was compared to complex fertilizer, organic fertilizer and compost to evaluate the fertilizing effect of struvite deposit. Laboratory pot test showed that the struvite deposit better enhanced lettuce growth in comparison to commercial fertilizers. It was revealed that the growth rate of lettuce was simultaneously controlled by phosphorus (P) and magnesium (Mg). Moreover, nutrients such as nitrogen (N), P, K, calcium (Ca) and magnesium (Mg) were abundantly observed in the vegetable tissue of struvite pot. Meanwhile, struvite application led to the lower accumulation of mercury (Hg), lead (Pb), chromium ($Cr^{6+}$) and nickel (Ni). In addition, no detection of cadmium (Cd), arsenic (As) and nickel (Ni) in the lettuce tissue was observed in struvite application pots. The experimental results proved that the optimum struvite dosage for lettuce cultivation was 0.5 g struvite/kg soil. The column experiments clearly showed that ammonia nitrogen was more slowly released from struvite deposit than from complex fertilizer. Consequently, it was concluded that the struvite deposits recovered from swine wastewater were effective as a multi-nutrient fertilizer for lettuce cultivation.

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.886-889
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• 2018

This article presented two-staged chemical precipitation for radioactive wastewater decontamination by using chemical agents. The total amount of radioactive wastewater was $35m^3$, and main radionuclides were Cs-137, Cs-134, and Co-60. Initial radioactivity concentration of the liquid waste was 2264, 17, and 9 Bq/L for Cs-137, Cs-134 and Co-60, respectively. Potassium ferrocyanide, nickel nitrate, and ferrum nitrate were selected as chemical agents at high pH levels 8-10 according to the laboratory jar tests. After the process, radioactivity was precipitated as sludge at the bottom of the tank and decontaminated clean liquid was evaluated depending on discharge limits. By this precipitation method decontamination factors were determined as 66.5, 8.6, and 9 for Cs-137, Cs-134, and Co-60, respectively. By using the potassium ferrocyanide, about 98% of the Cs-137 was removed at pH 9. At the bottom of the tank, radioactive sludge amount from both stages was totally $0.98m^3$. It was transferred by sludge pumps to cementation unit for solidification. By chemical processing, 97.2% of volume reduction was achieved. The potassium ferrocyanide in two-staged precipitation method could be used successfully in large-scale applications for removal of Cs-137, Cs-134, and Co-60.

• 상하수도학회지
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• 제19권2호
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• pp.144-148
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• 2005

The industrial development of large scale deep bed filters has been a very important step in the process of drinking water production and more recently in the tertiary treatment of wastewater. The target of deep bed filtration is the retention is the retention of small particles generally smaller than 30 microns at relatively small concentration, generally less than 30 mg/l from natural water (surface water or aquifers) or secondary treated wastewater. The relation between the retention efficiency and the characteristics of the particles has been extensively studied experimentally and through different models of retention. During the last years the development of new technologies (fiber filter, membrane modules) lead to more intensive processes compared to conventional sand filtration. Fiber filters can combine intensification with a decrease in specific energy needed however they cannot be operated under gravity like sand filters. Membrane filters (UF or MF) are much more intensive and efficient than sand filters. The specific energy needed is not so high (about $0.1Kwh/M^3$) but is higher than sand or fiber filter. A Life Cycle Analysis (LCA) has to be made for a complete comparison between these technologies taking in account that the efficiency of particle retention obtained by membrane filters is unique.

• Water Engineering Research
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• 제1권4호
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• pp.309-320
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• 2000

In this study, laboratory study of the behavior of wastewater discharged from the Boston ocean outfall was compared with the predictions of mathematical models. The dta sets cover broad ranges of discharge conditions and oceanic conditions, and are associated with a typical type of outfall discharges with multiport diffusers. The laboratory data sets were obtained in density stratified towing tanks. These data sets were used to evaluate four commonly used models: UM, UDKHDEN, RSB and CORMI$\times$2 for minimum dilution, the height to the top of the wastefield, and wastefield thickness. For minimum diluation and height to the top of the wastefield, UM and RSB predictions agree well with laboratory data. UDKHDEN overestimated the minimum dilution and height to the top of the wastefield while CORMI$\times$2 underestimated these values. All of the model predictions for the wastefield thickness were widely scattered. about the measured values. The hydraulic model study reproduced the major features observed in the laboratory. It also afforded considerable insight into the mechanics of mixing of multiport risers which could not have been obtained either from the laboratory test or the mathematical models.

• Membrane and Water Treatment
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• 제9권1호
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• pp.17-21
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• 2018

A series of laboratory scale experiments were performed to investigate the feasibility of membrane separation technology for natural rubber (NR) wastewater treatment and reuse. Three types of spiral wound membranes were employed in the cross-flow experiments. The NR wastewater pretreated by sand filtration and cartridge filtration was forced to pass through the ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes successively. The UF retentate, which containing abundant proteins, can be used to produce fertilizer, while the NF retentate is rich in quebrachitol and can be used to extract quebrachitol. The permeate produced by the RO module was reused in the NR processing. Furthermore, about 0.1wt% quebrachitol was extracted from the NR wastewater. Besides, the effluent quality treated by the membrane processes was much better than that of the biological treatment. Especially for total dissolved solids (TDS) and total phosphorus (T-P), the removal efficiency improved 53.11% and 49.83% respectively. In addition, the removal efficiencies of biological oxygen demand (BOD) and chemical oxygen demand (COD) exceeded 99%. The total nitrogen (T-N) and ammonia nitrogen (NH4-N) had approximately similar removal efficiency (93%). It was also found that there was a significant decrease in the T-P concentration in the effluent, the T-P was reduced from 200 mg/L to 0.34 mg/L. Generally, it was considered to be a challenging problem to solve for the biological processes. In brief, highly resource utilization and zero discharge was obtained by membrane separation system in the NR wastewater treatment.

• 한국습지학회지
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• 제19권4호
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• pp.501-507
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• 2017

산업하수 내 함유된 고농도 중금속(니켈)은 하수처리장 질산화율 감소의 원인으로 지목되고 있다. 본 연구에서는 고농도 니켈을 함유한 산업하수의 질산화율 분석 및 개선 방안을 도출하고자 실험실 규모 반응조 운전을 실시하였다. 운전 결과를 고농도 니켈을 함유한 경우 질산화율은 20% 내외로 낮은 범위를 보였지만, 저농도 니켈이 유입되었을 경우 질산화율이 향상(70% 이상)되었다. 질산화율의 차이를 보인 주요 원인은 니켈이 반응조 내 미생물의 활성을 감소시킨 것으로 AUR과 SNR 분석을 통해 나타났다. 또한 고농도 니켈이 유입될 경우, 체류시간 증가와 더불어 질산화율이 증가하였다. 즉, 고농도 중금속(니켈)을 함유한 하수의 경우 미생물 관리 및 체류시간 증가를 통해 안정적인 질산화율을 확보할 수 있을 것으로 판단된다.

• 한국방재학회 논문집
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• 제11권2호
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• pp.185-192
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• 2011

BNR공정은 반류수와 가축분뇨에 포함된 고농도의 질소를 제거하는데, 효과적인 공정이다. 특히 고농도의 질소제거에 있어서 완전질산화 반응에 비해 이점을 가지는 아질산화 반응을 유도하고 영향을 미치는 인자들에 대해 다양한 연구결과가 보고되었다. 그 중 유기물의 영향에 대해 많은 연구가 이루어졌는데, 유기물은 아질산화 반응에 관련이 있는 것으로 보고되고 있다. 본 연구에서는 반류수 중 혐기 소화 상징액, 가축분뇨, 혐기 소화를 거친 가축분뇨를 이용하여 실험실 규모의 아질산화 반응조를 운전하였다. 운전 결과를 분석하여, 아질산화 반응에 유기물이 미치는 영향에 대해, 유기물 성상에 따라 분석하였다. 분석 결과 아질산화 반응은 유기물에 영향을 받으며, 유기물 성분 중 $S_S$에 대해 영향을 가장 크게 받는 것으로 나타났다. 따라서 유기물을 하나의 성분으로 보지 않고 그 형태에 따라 세분화하여 관리해야 한다.

• 한국응용곤충학회:학술대회논문집
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• 한국응용곤충학회 2003년도 추계 학술발표회
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• pp.161-161
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• 2003