• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.540-546
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• 2006

Effects of organic and inorganic additives on the SNCR reaction of NOx were investigated in a pilot scale flow reactor with a variation of operating parameters. NOx reduction efficiency increased with the increase of a residence time and an initial NOx concentration. NOx reduction reaction by urea solution started to appear about 850 and then reached to maximum value around $970^{\circ}C$. NOx reduction efficiency also increased with the increase of NSR (Normalized Stoichiometric Ratio) up to 2.0. Addition of ethanol and phenol as an organic additives shifted the optimum temperature window to lower region with decreasing the maximum NOx reduction efficiency. This might be due to the side reaction of hydrocarbon in ethanol structure. NaOH addition widened the temperature window and enhanced the NOx reduction efficiency about 10％ due to the chain reaction of NaOH and the reduction of $N_2O$.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.6
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• pp.449-455
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• 2013

The effect of recycling ratio and fixed media on nitrate and phosphate removal was investigated in a pilot-scale wastewater treatment unit using synthetic wastewater. Addition of fixed media increased nitrate removal from 45 to 58% while no noticeable change was observed for Chemical Oxygen Demand (COD) and phosphate removal (<5%). Nitrate removal efficiency also enhanced (Ca 7%) when the influent wastewater flow was doubled (2Q), however phosphate removal was decreased from 40.9 to 26.6% with the increasing recycling rate. The attached biomass analysis showed the presence of bacteria (73.4 $mg/cm^2$) on the surface of added media in anoxic reactor. Pseudomonas aeruginosa a common denitrifying bacterium dominated the bacterial growth (58%) in the anoxic reactor which was determined using Fluorescence In Situ Hybridization (FISH) analysis.

• Journal of Korean Society on Water Environment
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• v.24 no.4
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• pp.436-441
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• 2008

This work experimentally determined the effect of operating parameters such as temperature and solid retention time (SRT) on the phosphorus removal of municipal wastewater with waste-tire media. The experiments were carried out in pilot-scale moving bed biofilm reactor filled at a 0.15 filling ratio with the media. Total phosphorus (TP) removal efficiency was $91{\pm}5$, $75{\pm}16$, and $59{\pm}14%$ at the temperature of 9~10, 10~20, and $20{\sim}26^{\circ}C$, respectively. TP removal efficiency was $71{\pm}17$, $74{\pm}16$, $74{\pm}16$, and $68{\pm}18%$ at the SRT of 3.5~5, 5~10, 10~15, and 15~20 days, respectively. At the nitrate concentration of 1~3, 3~6, and 6~9 mg/L, TP removal efficiency was $82{\pm}9$, $68{\pm}18$, $47{\pm}7%$, respectively. The concentration of total phosphorus in the effluent was $0.1{\sim}1.8(0.8{\pm}0.4)mg/L$ regardless of operating conditions, which meets Korean phosphorus limit value, 2 mg/L, for discharge into receiving waters.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.507-516
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• 2008

This research was conducted to elucidate the effect of temperature on the nitrogen removal of municipal wastewater with waste-tire media. The experiments were carried out in laboratory-scale batch reactor and pilot-scale moving bed biofilm reactor filled at a 0.15 filling ratio with waste-tire media, respectively. In batch tests, specific nitrification rate(SNR) with media was 3.4 mg NH$_4^+$-N/g Mixed-Liquor Volatile Suspended Solid(MLVSS)$\cdot$hr, compared with 1.7 mg NH$_4^+$-N/g MLVSS$\cdot$hr without media. In pilot-scale test with media, total nitrogen removal efficiency increased from 53 $\pm$ 8% to 76 $\pm$ 5% as the temperature increased from 9$\sim$10$^{\circ}C$ to 20$\sim$24$^{\circ}C$. At the temperature of 9$\sim$10$^{\circ}C$, 10$\sim$20$^{\circ}C$, and 20$\sim$24$^{\circ}C$, the SNRs were 0.8 $\pm$ 0.5, 3.1 $\pm$ 1.9, and 3.4 $\pm$ 2.1 mg NH$_4^+$-N/g MLVSS$\cdot$hr and the specific denitrification rates(SDNR) were 0.6 $\pm$ 0.2, 1.1 $\pm$ 0.6, 1.4 $\pm$ 0.6 mg NO$_3^-$-N/g MLVSS.hr, respectively. The overall activities of biomass in anaerobic, anoxic, and oxic zones at 20$\sim$24$^{\circ}C$ increased to 22, 20, and 15%, compared with those at 9$\sim$10$^{\circ}C$, respectively. The activity distribution of Nitrosomonas and Nitrobacter also increased with the increase of temperature.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.434-438
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• 2005

Nitrification characteristics and performance of wastewater treatment plants depend on not only temperature, pH, and dissolved oxygen of the wastewater but also species, distribution, and their metabolic stages of nitrifying bacteria. Due to their low specific growth rate, nitrifying bacteria are easy to wash out of the reactor and need long time to start-up and recover from damaged nitrifiers community. In order to overcome this limitation, nitrifying bacteria were coated on a polyurethane-based media. Laboratory and pilot-scale reactor had been designed and operated to compare the effect of coated nitrifying bacteria on wastewater nitrification efficiency and performance. Furthermore, the species and quantitative distribution of nitrifying bacteria were also investigated in the suspension and on the media. The results showed that nitrifier-coated reactor had better nitrification efficiency and performance than the control experiments. It also demonstrated that the amounts of total nitrifying bacteria of a coated reactor was higher than other reactors and it increased with operation time and wastewater temperature.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.2
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• pp.57-65
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• 2008

Wastewater containing strong organic matter is very difficult to treat by utilizing general sewage treatment plant. but the wastewater is adequate to generate biomass energy (bio-gas; methane gas) by utilizing anaerobic digestion. EcoDays Plug Flow Reactor (E-PFR), which was already proved as an excellent aerobic wastewater treatment reactor, was adapted for anaerobic food wastewater digestion. This research was performed to improve the efficiency of bio-gas production and to optimize anaerobic wastewater treatment system. Food wastewater from N food waste treatment plant was applied for the pilot scale experiments. The results indicated that the efficiency of anaerobic wastewater treatment and the volume of bio-gas were increased by applying E-PFR to anaerobic digestion. The structural characteristics of E-PFR can cause the high efficiency of anaerobic treatment processes. The unique structure of E-PFR is a diaphragm dividing vertical hydraulic multi-stages and the inversely protruded fluid transfer tubes on each diaphragm. The unique structure of E-PFR can make gas hold-up space at the top part of each stage in the reactor. Also, E-PFR can contain relatively high MLSS concentration in lower stage by vertical up-flow of wastewater. This hydraulic flow can cause high buffering capacity against shock load from the wastewater in the reactor, resulting in stable pH (7.0~8.0), relatively higher wastewater treatment efficiency, and larger volume of bio-gas generation. In addition, relatively longer solid retention time (SRT) in the reactor can increase organic matter degradation and bio-gas production efficiency. These characteristics in the reactor can be regarded as "ideal" anaerobic wastewater treatment conditions. Anaerobic wastewater treatment plant design factor can be assessed for having 70 % of methane gas content, and better bio-gas yielding and stable treatment efficiency based on the results of this research. For example, inner circulation with generated bio-gas in the reactor and better mixing conditions by improving fluid transfer tube structure can be used for achieving better bio-gas yielding efficiency. This research results can be used for acquiring better improved regenerated energy system.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.86.1-86.1
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• 2010

예비개질기(Pre-reformer)는 중대형 내부개질형 용융탄산염 연료전지(MCFC) 시스템에서 다양한 연료를 사용하기 위한 필수적인 화학반응기이다. 예비개질기는 스택 전단에 설치함으로서 스택 내부의 열균형을 유지하고, 다양한 원료를 연료로 이용할 수 있도록 하며, 황화물로부터 후단의 개질촉매 및 전극촉매를 보호하여 주개질 반응의 부담을 감소시켜 MCFC 시스템의 내구성 향상의 중요한 역할을 한다. 본 연구는 예비개질 반응기 설계에 CFD 모델링을 적용하기에 앞서 파일롯 반응기 내 농도/ 온도 구배를 측정하고자 하는 목적으로 수행되었다. 반응가스로는 천연가스 내 고차탄화수소(C2 이상) 중 상대적으로 높은 농도를 가진 에탄을 이용하였고, MCFC용 예비개질기의 운전특성을 고려하여 비교적 낮은 온도와 높은 수증기/탄소 비에서 단열반응기로 실험을 진행하였다. 향후 본 실험결과를 이용하여 CFD 모델링에 대한 검증을 수행할 예정이며, 하수처리장부생가스(ADG)/ 매립지 가스(LFG)용 MCFC 시스템을 위한 예비개질기 설계에도 적용을 하고자 한다.

• Journal of environmental and Sanitary engineering
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• v.11 no.2
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• pp.43-52
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• 1996

Using rotating biological contactor(RBC) with artificial endogenous stage and aerobic fixed biofilm reactor(AFBR), organic material removal and biological nitrification of piggery wastewater has been studied at a pilot plant. RBC was operated in the endogenous phase at a interval of every 25 days. The concentration of COD, BOD and TKN in influent wastewater were from 2,940 to 3,800 mg/L, from 1,190 to 1,850 mg/L and from 486 to 754 mg/L respectively. The maximum active biomass content represented as VSS per unit aera was $2.0mg/cm$^{2}$ and biofilm dry density of $17mg/cm^{3}$ was observed at biofilm thickness of $900{\;}{\mu}m$. It was observed that the pilot scale RBC/AFBR process exhibited 72 percentage to 93 percentage of BOD removal, In order to obtain more than 90 percentage of BOD removal, the organic loading rate to the RBC/AFBR process should be maintained less than $0.09{\;}m^{3}/m^{2}{\cdot}day(125.9g{;\}BOD/m^{3}{\cdot}d$. The TKN removal efficiencies was from 45.5 to 90.9 percentage according to vary influent loading rate, It was estimated that the RBC/AFBR process consumed approximately 6.2 mg/L(as $CaCO_{3}$) of alkalinity per 1 mg/L of $NH_{3}$-N oxidized as the nitrification took piace.

• Environmental Engineering Research
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• v.20 no.3
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• pp.277-284
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• 2015

Experiments for highly concentrated contaminants in pig waste slurry were carried out for the feasibility test of a pilot-scale innovative process scheme of engaging autothermal thermophilic aerobic digestion (ATAD) and expended granular sludge bed (EGSB) followed by sequencing batch reactor (SBR) system. Contaminants in pig waste slurry such as organic substance, total nitrogen (TN), ammonia nitrogen and total phosphorus (TP) contents were successfully reduced in the system. Total volatile solids (TVS) and chemical oxygen demands (COD) for organic matter in the feed were 32.92 g/L and 42.55 g/L respectively, and they were reduced by about 98.7% and 99.2%, respectively in the system. The overall removal efficiencies for TN and ammonium nitrogen were found to be 98.1 and 98.5%, respectively. The overall removal efficiency for total phosphorus was also found to be 92.5%. Faecal coliform density was reduced to <$1.2{\times}10^4CFU/g$ total solids. Biogas and $CH_4$ were produced in the range of 0.39-0.85 and $0.25-0.62m^3/kg$ [VS removed], respectively. The biogas produced in the system comprised of $295{\pm}26ppm$ (v/v) [$H_2S$].

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.4
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• pp.113-119
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• 2001

Ammonia emissions during composting of hog manure mixed with sawdust were studied in four runs comprising a total of 22 pilot-scale reactor vessels. These four runs extended previous work and both verified and extended the previous conclusions. The pilot-scale vessels were 205 L insulated stainless steel drums that were aerated either continuously (high/low thermostatically controlled fans) or intermittently (5 min high fan 55 min off). Temperature ammonia emissions air flow rates carbon dioxide production and oxygen utilization moisture and dry matter reduction initial and final chemical compositions were measured. Ammonia emissions from the intermittently aerated vessels were only about 50% as great as those from the continuously aerated ones but this was found to be a result more related to total air flow than to aeration technique. All of the data for total result more related to total air flow were fitted with a linear regression line y=0.139x+29.835 where y is ammonia expressed as g of N and x is air flow in kg with $R^2$=0.6808. this general trend indicates that about 50% reduction in ammonia emissions can be achieved with 75% reduction in air flow. For the aeration techniques used the minimum oxygen level in te exhaust gas from the vessels was 5% and this is probably a resonable lower limit constraining air flow reduction. However within this constraint lower air flow now appears to be a technique that can reduce odorous ammonia emissions.