• 한국산업융합학회 논문집
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• 제6권1호
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• pp.81-86
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• 2003

For the simultaneous removal of $SO_2$/NOx from an iron-ore sintering plant, industrial plasma experiments have been conducted with a flue gas flow rate of $5,000Nm^3/hr$. The maximum 40kW power using the magnetic pulse compression (MPC) system generates a peak value of 100-150kV pulse voltage with its risetime of 200nsec and full width at half maximum (FWHM) of 500nsec, and with a frequency <300Hz. The plasma reactor module adopts a wire-plate structure with a gap of 200-400mm ID between plates. Initial concentrations of $SO_2$ and NOx were around 100-150ppm, respectively in the presence of 15% $O_2$ and <10% $H_2O$. Various reaction parameters such as specific energy ($Whr/Nm^3$), $NH_3$ injection with corona discharge, flow rate and injection of hydrocarbons were investigated for $SO_2$/NOx removal characteristics. About 90/65% of $SO_2$/NOx were simultaneously removed with a specific energy of $3.0Whr/Nm^3$ when both $NH_3$ and hydrocarbons were injected. Practical implications that the pilot-scale plasma results provide are further discussed.

• 공업화학
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• 제20권4호
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• pp.437-442
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• 2009

$TiO_2$, $Al_2O_3$를 담체로 한 Pt계 촉매에서 NOx, soot의 동시 제거 반응과 촉매의 열충격에 대한 연구를 수행하였다. 실험은 NOx와 soot의 반응을 독립 또는 동시에 반응시킨 조건으로 수행하였으며 그 결과 담체의 종류 및 상에 따라서 서로 상이한 NOx 제거능력과 soot 산화력을 나타내었고, soot의 산화시작온도의 결정은 NOx 제거능력과 상관관계가 있었다. NOx, soot의 동시 반응 시에는 생성된 $NO_2$에 의하여 soot 산화시작온도가 저온으로 이동하였다. 또한 열충격에 대한 NOx 제거율은 Pt/$Al_2O_3$ 촉매가 Pt/$TiO_2$ 촉매에 비하여 효율저하가 적게 일어났으며 soot 산화력은 활성점인 Pt의 소결현상에 의하여 촉매에 관계없이 모두 감소하였다.

• 환경위생공학
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• 제13권2호
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• pp.57-65
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• 1998

In this research, Effect of C/N ratio on nutrient removal in intermittently aerated activated sludge system(IAASS) was investigated with dormitary, building and swine wastewater. Three types (2-stage, 4-stage, modified) of IAASS were operated. Time interval of aeration/nonaeration in IAASS was 1hr/1hr. In treatment of Dormitary wastewater(BOD/T-N ratio : 4.4), Building wastewater (BOD/T-N ratio : 3.14) and swine wastewater(BOD/T-N ratio : 3.84), Nitrogen removal efficiency of 80, 70 and 90.4% was achieved, respectively. Nitrogen removal in IAASS was a great influenced on influent C/N ratio, efficient nitrogen removal was achieved at BOD/T-N ratio over 4. In IAASS operation, $\Delta $BOD mg/L/$\Delta $ nitrogen mg/L ratio was about 4-6. Simultaneous removal of organic, nitrogen and phosphorus in IAASS can achieved. And influent organic was efficiently utilized in denitrification. IAASS could be one of the best alternative process for the retrofit of conventional activated sludge system for the removal of nutrients.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.643-648
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• 2000

The purpose of this study is to remove the ammonia by using the ion exchange effect of natural zeolite (clinoptilolite in this system) and artificial zeolite and remove the organic material by using the Absorbent Biofilter. On the removal of ammonia, natural zeolite is the more effective than artificial zeolite But on the simultaneous removal of ammonia and phosphorus, artificial zeolite is the more effective than natural zeolite.

• 대한환경공학회지
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• 제35권10호
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• pp.724-729
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• 2013

동시 질산화 탈질은 미세 용존 산소하에 한 반응조내에서 일어난다. 따라서, 본 연구에서는 인 방출을 위해 공기가 공급되는 MBR 전단에 혐기성 존을 만들어주었으며, 높은 DO 농도에서 탈질효율을 향상시켜 주기 위해서는 MBR 내에 배플을 설치하여 무산소 존이 이루어지게 하였다. 그리고 인 제거를 위한 테스트는 MBR 전단의 혐기성 반응조에 알럼 응집제를 투입하여 수행하였다. 질소 제거를 위한 SND의 최적 DO 농도 도출은 MBR 내 DO 농도를 2.0, 1.5, 1.0, 0.75 mg/L의 다양한 조건에서의 운전을 통해 수행하였다. 심지어 높은 알칼리성 하수라 알럼 응집제를 투입하였을 때 알칼리 용액 첨가 없이도 pH는 7.0~8.0로 유지되었다. TCODcr와 $NH_4^+$-N의 제거 효율은 모든 DO 농도에서 90% 이상이었다. DO 농도 2.0, 1.5, 1.0, 0.75 mg/L에서의 TN 제거효율은 각각 50, 51, 54, 66%이었다. DO 농도 0.75 mg/L 조건에서 알럼을 첨가한 결과 TN 제거효율은 54%로 감소하였다. 혐기성 반응조에 알럼을 투입한 결과 TP 제거효율은 29%에서 95%로 향상되었다. 그리고 알럼 투입 후 분리막 모듈의 화학적 세정 주기는 15~20일부터 40~50일으로 늘어났다.

• 상하수도학회지
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• 제20권4호
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• pp.559-571
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• 2006

The overall objective of this research was to find out the interrelation of coagulant and organic matter during rapid mixing process and to identify the change of organic matter by mixing condition and to evaluate the effect of coagulation pH. During the coagulation, substantial changes in dissolved organics must be occurred by coagulation due to the simultaneous formation of microflocs and NOM precipitates. Increase in the organic removal efficiency should be mainly caused by the removal of microflocs formed during coagulant injection. That is, during the mixing period, substantial amount of dissolved organics were transformed into microflocs due to the simultaneous formation of microflocs and NOM precipitates. The results also showed that 40 to 80% of dissolved organic matter was converted into particulate material after rapid mixing process of coagulation. During the rapid mixing period, for purewater, formation of dissolved Al(III) (monomer and polymer) constant by rapid mixing condition, but for raw water, the species of Al hydrolysis showed different result. During the rapid mixing period, for high coagulant dose, Al-ferron reaction increases rapidly. At A/D(Adsorption and Destabilization) and sweep condition, both $Al(OH)_3(s)$ and dissolved Al(III) (monomer and polymer) exist, concurrent reactions by both mechanism appear to cause simultaneous precipitation.

• International Journal of Precision Engineering and Manufacturing
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• 제8권4호
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• pp.10-15
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• 2007

Taguchi methods have been used for a long time to improve the product quality and process performance of a manufacturing system, Few researchers have applied this methodology in laser beam cutting (LBC) of sheet metals and found the considerable improvement in cut qualities. In all experimental investigations of LBC so far, the objective was to optimize the single quality characteristic at a time. In this paper the simultaneous optimization of multiple quality characteristics such as Kerf width and material removal rate (MRR) during pulsed Nd:YAG LBC of thin sheet of magnetic material (high Silicon-steel) has been presented using Taguchi's quality loss function. The results show the considerable improvement in multiple S/N ratio as compared to initial cutting condition. Also, the comparison of results from single and multi-objective optimization have been presented and it was found that the loss in quality is always possible shifting from single quality to multiple quality optimization.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.447-450
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• 2003

The feasibility of PENTANOX 4X for the simultaneous removal of nitrate and phosphate was investigated using micellar-enhanced ultrafiltration. Because PENTANOX 4X has cationic property at low pH, anionic contaminants can be bound to PENTANOX 4X micelle by electrostatic interaction. At pH 3, 90% of nitrate and 72% of phosphate were removed by 27 mM of PENTANOX 4X, which were equivalent to 20 mM of CPC. PENTANOX 4X of > 80 % was rejected by ultrafiltration membrane and did not make any counter-ion such as chloride for CPC which might cause second-pollution.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2009년도 춘계학술발표회
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• pp.145-147
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• 2009

Nutrients in wastewater should be removed prior to release in the receiving waters to prevent the occurrence of eutrophication. In this study, seawater is used to remove ammonia and phosphate by the formation of struvite ($MgNH_{4}PO_{4}{\cdot}6H_{2}O$). It aims to know the optimum conditions for the removal of nutrients using seawater as source of magnesium ions. Experiments were performed using jar tester and pH of ammonium-phosphate solutions were adjusted Samples were drawn at different mixing times. It was shown that simultaneous removal of ammonia and phosphate is rapid, with no significant reduction beyond 10 min of mixing Another important parameter is pH, where range 10-11 showed the optimum nutrient removal. Increase in the volume of seawater, which meant an increase in magnesium ions also lead to better removal.

• 한국환경보건학회지
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• 제30권2호
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• pp.84-91
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• 2004

Biological nutrient removal(BNR) from wastewater was performed by adopting various process configurations. The simultaneous biological organics, phosphorus and nitrogen removal of synthetic wastewater was investigated in a sequencing batch biofilm reactor (SBBR). The other reactor was operating as a reference, without biofilm being added. The cycling time in SBR and SBBR was adjusted at 12 hours and then certainly included anaerobic and aerobic conditions. Both systems has been operated with a stable total organic carbon(TOC), nitrogen and phosphorus removal performance for over 90 days. Average removal efficiencies of TOC and total nitrogen were 83% and 95%, respectively. The nitrification rate in SBR was higher than that in SBBR. On the contrary, the denitrification rate in SBBR was higher than that in SBR. The phosphorus release was occurred in SBBR, however, not in SBR because of the inhibition effect of NO$_3$$^{[-10]}$ .