• 한국물환경학회지
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• 제30권5호
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• pp.486-490
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• 2014

Industrial use of microwave heating as an alternative to conventional heating is becoming popular mainly due to dramatic reductions in reaction time. Therefore, this work experimentally determined the effect of microwave irradiation on ammonia nitrogen removal in wastewater. The effects of air flow rate (0.3~0.9 L/min), treatment temperature ($70{\sim}100^{\circ}C$), and initial pH (9~11) were characterized. As the air flow rate increased from 0.3 to 0.9 L/min, the ammonia removal rate constant (k) increased from -0.6642 to $-1.0755min^{-1}$. As the temperature increased from 70 to $100^{\circ}C$, k increased -0.0338 to $-1.0755min^{-1}$. As the pH increased from 9 to 11, k increased -0.2443 to $-1.0755min^{-1}$. Ammonia removal was strongly dependent on temperature and pH rather than air flow rate. The results show that microwave irradiation is effective in ammonia nitrogen removal in wastewater due to advantages of fast and effective processing.

• 청정기술
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• 제13권1호
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• pp.16-21
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• 2007

본 실험은 질화세균을 고정화한 충전층 생물반응기에서 저농도 암모니아성 질소(total ammonia nitrogen, TAN)의 제거 시 수력학적 체류시간(hydraulic residence time, HRT), 유입수 암모니아성 질소농도 및 온도에 의한 영향을 평가하였다. 수력학적 체류시간이 감소함에 따라 암모니아성 질소의 제거속도는 증가하였고, 암모니아성 질소의 제거 시 최적 수력학적 체류시간은 0.2시간이었다. 수력학적 체류시간이 0.2시간에서 암모니아성 질소의 제거속도는 $226.1\;g/m^3{\cdot}day$, 제거효율은 88.8%을 나타내었다. 유입수 암모니아성 질소 농도가 증가함에 따라 암모니아성 질소의 제거속도는 증가하였다. 온도 $20{\sim}35^{\circ}C$에서 암모니아성 질소의 제거속도와 제거효율은 일정하게 유지했다.

• 한국양식학회지
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• 제10권4호
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• pp.435-438
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• 1997

전기분해를 이용한 해수의 암모니아성 질소 및 대장균 제거에 효과적이었다. 암모니아의 제거효율은 전류의 세기가 클수록, 반응 시간이 길수록, 극판간격이 좁을수록 증가하였다. 해수내 250/100 m\ell$의 대장균은 모든 실험 조건에서 검출되지 않아, 살균 목적으로 전기분해가 매우 효과적이었다. 암모니아의 제거 효율은 잔류 염소의 농도에 따라 증가하였다. 암모니아의 제거 효율과 잔류 염소와의 관계는 다음과 같다.$NH_4^+-N(%)=4cdotlog[Residual\;chlorine(mg/\ell)+28(r=0.892)$

• 한국환경과학회지
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• 제10권3호
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• pp.233-237
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• 2001

Immobilized nitrifier bead in airlift bioreactor were used to remove high levels of ammonia nitrogen from synthetic wastewater. Polyvinylalcohol(PVA) bead for immmobilization of nitrifier consortium were prepared by PVA-boric acid method by varying concentration of PVA and nitrifier consortium. By determining viscosity, sphercity and tailing, the characteristics of prepared beads were investigated and the continous immobilization process was developed. Synthetic wastewater containg 25g/$\textrm{m}^3$ of ammonia nitrogen could be treated within 0.5 hour and the highest removal rate of ammonia nitrogen was 934.2g/$\textrm{m}^3{\cdot}$ day.

• 한국환경과학회지
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• 제8권2호
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• pp.177-182
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• 1999

Nitrifier consortium entrapped in Ca-alginate bead were packed into aerated packed bed bioreactor and non aerated packed bed bioreactor and the performances of two bioreactors were evaluated for the removal of ammonia nitrogen from synthetic aquaculture water. Total ammonia nitrogen(TAN) removal rate was decrease in aerated packed bed bioreactor below 0.3hr of hydraulic residence time(HRT), but increased in non aerated packed bed bioreactor until 0.5hr of HRT. At HRT of 0.05hr, TAN removal rate of non aerated packed bed bioreactor was about 335g TAN/㎥/day and the optimum ratio of packing height and inside diameter of reactor (H/D) was 4. The performance of two bioreactors indicated that non aerated packed bed bioreactor was better than aerated packed bed bioreactor in ammonia removal from synthetic aquaculture water.

• 환경위생공학
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• 제18권1호
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• pp.15-22
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• 2003

Treatability tests were conducted using EMC process to study the feasibility of applying this process as recycling-water treatment system in high density seawater aquaculture farm. To study the effect of organic and ammonia nitrogen loading on system performance, hydraulic retention time of reactor was reduced gradually from 12hr to 10min. The conclusions are can be summarized as follows. When the system HRT was reduced from 12hr to 10 min gradually, there was little noticeable change(reduction) in ammonia nitrogen removal efficiencies until 2hr of HRT, however, removal efficiencies were decreased dramatically when the system was operated under the HRT of less than 2hr. In case of organics(COD), there was no dramatic deterioration in removal efficiencies depending on HRT reduction. More than 90% of removal efficiencies were maintained successfully when the system was operated at the HRT of 10 min. In case of system performance depending on media packing ratio in reactor, there was little difference in each reactor performance depending on media packing ratio in reactor when the reactors were operated under the HRT of longer than 1hr, however, differences in reactor performances were considerably evident when the reactors were operated under the HRT of shorter than 1hr. That is, the more reactor was packed, the better reactor performed. When comparing reactor performance among 25%, 50%, 75% packed reactor, it can be judged that media packing ratio more than 50% plays no significant role in increasing reactor performance. For this reason, packing the media less than 50% is more reasonable way in view of economic. Such a tendency well agreed with the variation of ammonia-nitrogen removal efficiencies according to the media packing ratio in reactors at each HRT. Difference in effluent ammonia-nitrogen concentration between 50% media packing reactor and 75% media packing reactor was negligible. When comparing with the results of 25% packing reactor, difference was not so great.

• 환경위생공학
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• 제12권2호
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• pp.1-12
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• 1997

This research aims to develop biofilm process for the nutrient removal of piggery wastewater. The developed process is the four stage anoxic-oxic biofilm process with recirculation of the final effluent. In summery, the results are as follows: 1. Nitrification in the piggery wastewater built up nitrite because of the high strength ammonia nitrogen. The nitrification of nitrobacter by free ammonia was inhibited in the total ammonia nitrogen loading rate with more than 0.2 kgNH$_{3}$-N/m$^{3}$·d. 2. The maximal total ammonia nitrogen removal rate was obtained at 22$\circ $C and without being affected by the loading rate. But total oxidized nitrogen production rate was largely affected by loading rate. 3. Autooxidation by the organic limit was a cause of the phosphorus release in the aerobic biofilm process. But the phosphorus removal rate was 90 percent less than the influent phosphorus volumetric loading rate of above 0.1 kgP/m$^{3}$·d. Therefore, the phosphorus removal necessarily accompanied the influent loading rate. 4. On the anoxic-oxic BF process, the total average COD mass balance was approximately 67.6 percent. Under this condition, the COD mass removal showed that the cell synthesis and metabolism in aerobic reactor was 42.8 percent and that the denitrification in anoxic reactor was 10.7 percent, respectively.

• 한국물환경학회지
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• 제24권3호
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• pp.311-316
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• 2008

This study aimed to obtain equilibrium concentration on adsorption removal of ammonia nitrogen by activated carbon, to express the adsorption characteristics following Freundlich isotherm and also, based on the value obtained, to investigate the relationship between physical characteristics of activated carbon and dynamics of ammonia nitrogen removal by obtaining rate constant and effective pore diffusivity. The results summarized from this study are as follows. It was noted that powdered activated carbon showed better adsorption ability than granular activated carbon. The value of constant (f) of Freundlich isotherm of powered activated carbon was $4.6{\times}10^{-8}$ which is bigger than that of granular activated carbon. The adsorption rate constant on ammonia nitrogen of powered activated carbon with high porosity and low effective diameter was highest as 0.416 hr-1 and the effective pore diffusivity ($D_e$) was lowest as $1.17{\times}10^{-6}cm^2/hr$, and the value of ammonia nitrogen adsorption rate constant of granular activated carbon was $0.149{\sim}0.195hr^{-1}$. It was revealed that, with the same amount of dosage, the adsorptive power of activated carbon with lower effective diameter and bigger porosity was better and its rate constant was also high. With a little adsorbent dosage of 2 g, there was no difference removal ability of ammonia nitrogen as change of adsorption properties.

• 청정기술
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• 제29권4호
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• pp.297-304
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• 2023

첨단 전자 제품 산업의 비약적인 발전은 환경적 측면에서 고농도 암모니아 폐수의 증가를 초래했다. 고농도 암모니아 폐수를 안정적으로 처리하기 위해 다양한 방법의 기술이 시도되고 있으나, 지금까지 성공적인 기술이 개발되어 적용되지는 못하고 있다. 본 연구에서는 첨단 전자산업에서 발생하는 고농도 암모니아 함유 폐수에 대하여 밀폐(closed) 순환형 대향류 충전탑 형식의 실증설비를 이용하여 온도, 공기부하율 그리고 폐수부하율 변화에 따른 암모니아성 질소의 제거효율과 제거 특성을 평가하였다. 폐수량 20.8 m³ h^-1, 공기량 18,000 Nm³ h^-1의 운전 조건에서 온도를 45, 50, 55 그리고 60℃로 변경하여 운전한 결과, 암모니아성 질소(NH₃-N)의 제거율은 각각 87.5, 93.4, 96.8 및 98.7%로 온도가 제거율에 미치는 가장 큰 영향 인자임을 알 수 있었다. 공기부하율을 증가시키면 제거율도 증가하나, 흡수탑의 액적(droplet)이 탈기탑으로 유입되어 제거율 증가는 크지 않았다. 폐수 부하율이 변경되어도 제거율은 크게 변하지 않았는데, 이는 제거율에 영향이 없는 것이 아니라, 상대적으로 높은 공기부하율에 기인한 것으로 판단된다. 실증연구를 통해 암모니아 탈기법은 첨단 전자산업에서 발생하는 고농도 암모니아 폐수를 안정적으로 처리할 수 있는 적정한 공법임을 확인할 수 있었다.

• 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.