• 대한환경공학회지
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• 제27권2호
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• pp.206-214
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• 2005

본 연구는 도시하수 처리시 부유성장 미생물만을 이용하는 표준 활성슬러지 공정(Conventional Activated Sludge; CAS) 및 MLE(Modified Ludzack-Ettinger) 공정과 부유 및 부착 미생물을 동시에 활용하는 하이브리드(hybrid)형 공정인 M-Dephanox(Modified-Dephanox) 공정의 유기물, 질소 및 인 제거효율을 상호 비교 검토하고자 하였다. M-Dephanox 공정은 기존 Dephanox 공정의 단점을 극복하기 위하여 고안된 공정으로서 기존 Dephanox 공정에 비해 탈질 효율을 증가시킬 수 있다. 연구 결과 부유 성장 미생물을 이용하는 MLE 공정에 비해 하이브리드형 공정인 M-Dephanox 공정의 TCOD, T-N 및 T-P 제거효율이 각각 12.3, 18.6, 28.2% 더 높게 관찰 되었다. M-Dephanox 공정이 MLE 공정에 비해 유기물 및 질소 제거 효율이 더 높은 원인은 M-Dephanox 공정이 하이브리드 공정이자 다단 슬러지 공정(multi-sludge)인 동시에 생흡착(biosorption)을 이용한 효과적인 유기물 이용 기작이 있기 때문이다. M-Dephanox 공정의 질산화 반응조에서의 암모니아성 질소 제거효율은 약 2hr의 수리학적 체류시간에서 약 96.7%로 나타나 Dephanox 공정과 관련한 기존 문헌에서 보고된 5 hr의 체류시간 보다 3 hr 짧은 수리학적 체류시간에서도 높은 암모니아성 질소 제거효율을 관찰 할 수 있어 전체 공정의 수리학적 체류시간을 줄이는데 커다란 역할을 할 것으로 기대된다.

• 한국환경과학회지
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• 제6권4호
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• pp.409-415
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• 1997

In order to Investigate the possibility as a simple technique of wastewater treatment for recirculating aquaculture system, the experiment by a biofilter unfit was carried out. The high and stable removal efficiency of nitrogen could be obtained by selecting the optimum recycle ratio and DO concentration. It was found that the proper combination of nitrifacation and denitrfication step in the reactor would be required for increasing the removal efficiency. The extent of nitrogen removal gradually decreased UO the rise of re- cycle ratio since the depression of denitrificatlon by the lack of hydrogen donor. The depression of nitrogen removal was overcome by increasing the CIN ratio In the wastewater. The extent of phosphorus removal was increased slightly with the increase of DO concentration and recycle ratio, but high removal efficiency was not observed. However, the extent of COD removal was not affected by recycle ratio and DO concentration and showed the stable removal of above 90%.

• 한국지반환경공학회 논문집
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• 제15권5호
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• pp.39-46
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• 2014

본 연구에서는 다양한 호기/혐기조건에서 유류오염물질인 및 MTBE의 생분해 특성을 비교하고, 특히 탈질 조건에서 질산염 영향을 조사하여 유류오염지역의 혐기적 자연정화방법의 적용 가능성을 평가하고자 한다. 단일기질 및 혼합기질 분해실험 결과, BTEX는 3가지 실험조건에서 차이는 있었으나 모두 분해가 일어났다. 그러나 benzene과 p-xylene은 호기성 조건에서 초기 공급된 용존 산소의 부족으로 인하여 분해가 지연되는 것으로 나타났다. 또한 혼합기질에서는 단일기질에 비해 BTEX 분해가 기질 경쟁관계로 인해 다소 지연되는 경향이 관찰되었다. MTBE는 탈질 조건에서만 생분해가 관찰되었으나, TBA 축적 없이 $CO_2$로 무기화되는 것으로 추정된다. 또한 BTEX 및 MTBE 분해에 대한 질산염 농도의 영향 실험 결과, 저농도(>50 mg/L)에서 BTEX 분해는 제한되었으며, 고농도 질산염(<200 mg/L) 조건하에서는 BTEX 분해가 억제되는 현상이 관찰되었다. 본 연구에서 도출된 결과는 유류오염지역의 경우 호기/혐기성 조건에서 자연 생분해를 유도할 수 있을 것으로 예상된다.

• 상하수도학회지
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• 제23권5호
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• pp.527-537
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• 2009

Three sets of parallel MBRs (reactor No.1, reactor No.2, reactor No.3) maintaining an MLSS of 4,000 mg/L, 6,000 mg/L and 8,000 mg/L, respectively, were operated to investigate the effect of various HRTs and DO concentration of MBRs on the removal efficiency of organic matters and nitrogen. The HRTs were operated on 4 hr, 6 hr, 8 hr. DO concentrations were ranged 1.5~2.0 mg/L and 0.5~1.0 mg/L respectively on each HRT conditions. MBR was divided into an aerated part and non-aerated part by baffle placed under the water. DO concentrations were controlled by altering the position of baffle. In terms of TSS and CODCr, all systems had a similar level of the removal under varied HRTs and MLSS. TSS removal efficiency was more than 99% and CODCr removal was ranged 94~97% under all conditions. Under the same condition on the HRT and MLSS concentrations, DO concentrations did not affect the organic removal efficiency. On the nitrification efficiency, with high DO concentration, as HRT or MLSS increased, the slight increment of nitrification efficiency was observed. However, under the low DO concentration, increase of MLSS and HRT resulted in larger increase of the nitrification efficiency. At the same HRT and MLSS, the nitrification efficiency increased greatly with up to 16% as DO increased. When the HRT increased from 4hr to 8hr, the denitrification efficiency slightly increased under most of conditions. However, the increase of MLSS resulted in about 19~39% denitrification efficiency increment. MLSS concentrations showed great effect on the denitrification. The increase of the DO concentration at the same HRT and MLSS resulted in decrease of denitrification efficiency with up to 27%. In all systems, the denitrification efficiency had more influence on the TN removal efficiency than nitrification efficiency. So, MLSS concentration has greater effect on the TN removal than HRT and DO. The TN removal efficiency increased as MLSS increased with up to 37%. As a result, the highest TN removal efficiency was observed 79.0% at the condition showed the highest denitrification efficiency that DO of 0.5~1.0 mg/L, an HRT of 8 hr, and 8,000 mg/L of MLSS concentration were maintained.

• 대한환경공학회지
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• 제29권8호
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• pp.922-929
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• 2007

암모니아의 질산염으로의 산화는 2개의 산화과정으로 구분된다. 나이트로좀머나스(Nitrosomonas)에 의한 암모니아의 아질산염으로의 산화와 나이트로박터(Nitrobacter)에 의한 아질산염의 질산염으로의 산화이다. 아질산염 축적 과정을 거치는 질소의 제거는 포기를 위한 에너지의 절약, 탈질과정에서 투입되는 유기물의 절약 및 발생되는 슬러지의 양을 감소시킬 수 있는 다양한 장점들을 가지고 있다. 본 연구에서는 아질산염 축적의 조건들을 찾기 위해 막분리 장치를 장착한 생물분리막 반응조(MBR)가 사용되었다. 생물 분리막 반응조는 성장속도가 늦어 쉽게 유실되어질 수 있는 독립영양 질산화 박테리아를 반응조내 충분히 유지시키는데 중요한 역할을 한다. 반응조내 용존산소와 암모니아의 농도를 변화시키며 아질산염 축적의 영향인자들을 조사하였다. 연구의 결과로 반응조내 높은 암모니아 농도는 아질산염 축적을 시작하는데 매우 효과적이었으며, 이러한 효과는 반응조내 낮은 용존산소 농도가 동시에 존재할 시 더욱 강화되었다. 낮은 용존산소 농도 $c'_{O2}<0.3$ $mgL^{-1}$ $O_2$와 높은 암모니아 농도 $c_{NH3}=6.3\sim14.9$ $mgL^{-1}$ $NH_3N$에서 아질산염 축적율 74%에 달성될 수 있었다. 특히 아질산염 축적이 많은 연구자들이 제시하는 것처럼 생물막 반응조에서 뿐만 아니라, MBR 반응조에서도 일어날 수 있음을 밝힌 것은 본 연구의 중요한 성과라 할 것이다.

• 유기물자원화
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• 제12권1호
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• pp.84-93
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• 2004

본 연구는 생물학적 처리공정의 하나인 SBR을 이용하여, 양돈폐수중의 유기물과 질소, 인의 동시 제거를 목적으로 적정의 수리학적 체류시간(HRT)과 반응기간 중 교반/폭기 시간비(M/A) 및 적정의 교반/폭기 시간비에서의 외부탄소원의 주입기간(Injection Time)에 따른 변화에 따른 실험 결과로부터 다음과 같은 결론을 얻었다. (1) $NH_4{^+}-N$의 제거효율은 M/A가 0.0/22.0일 때(Run 1) 가장 효율이 좋았으며, 외부탄 소원을 주입했을 경우 탈질균의 증식으로 인해서 질산화가 잘 이루어지지 않기 때문에 주입시간이 길어질수록 증가하였다. T-N의 제거효율은 M/A가 증가할수록, 외부탄소원 주입시간이 길어질수록 증가하였다. (2) T-P의 제거효율은 운전조건에 따라 큰 차이를 보이고 있으며, M/A가 증가할수록 제거효율은 증가하였으며, 외부탄소원의 주입기간을 두고 보았을때, 주입기간을 짧게 할 경우 탈질균의 증식으로 인해서 탈질이 더 효율적으로 이루어지기 때문에 그 제거효율은 증가하였다. (3) 총 반응시간 22시간 중 M/A 16.5/5.5, 무산소 기간의 16.5시간 중 15시간동안 외부탄소원을 주입했을 경우(Run 4-1)의 운전조건에서 유기물 및 질소 제거에 가장 효율적이었다. 각각의 효율을 살펴보면, $COD_{Cr}$, $COD_{Mn}$ 그리고 $BOD_5$인 경우, 각각 90.6%, 87.7% 그리고 96.1%이고, T-N의 경우 86.6%, T-P인 경우는 84.5%로 나타났다.

• 한국환경농학회지
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• 제28권4호
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• pp.371-377
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• 2009

In this study, simultaneous nitrification and denitrification (SND) from synthetic wastewater were performed to evaluate dissolved oxygen(DO) effects on chemical oxygen demand(COD) and nitrogen removal in a single membarne bio-reactor(MBR). DO levels in MBR at Run 1, 2, and 3 were 1.9~2.2, 1.3~1.6, and 0.7~1.0 mg/L, respectively. Experimental results indicated that DO had an important factor to affect COD and total nitrogen(TN) removal. SND were able to be accomplished in the continuous-aeration MBR by controlling ambient DO concentration. It is postulated that, because of the oxygen diffusion limitation, an anoxic micro-zone was formed inside the flocs where the denitrification might occur. From the results of this study, 96% of COD could be removed at DO of 0.7mg/L. At run 2 72.92% of nitrogen was removed by the mechanisms of SND (7.75mg-TN/L in effluent). In this study, SND was successfully occurred in a MBR due to high MLSS that could help to form anoxic zone inside microbial floc at bulk DO concentrations of 1.3~1.6mg/L.

• 한국물환경학회지
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• 제24권3호
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• pp.273-279
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• 2008

Space separation method that use independent reactor for nitrification and other reactor for denitrification has been commonly used for biological nitrogen removal process like $A^2O$ process. However, this method needs large space and complicate pipelines and time separation method such as SBR process have a difficulty in continuous treatment. Thus biological nitrogen removal process which is capable of continuous treatment, easy opeation and space saving is urgently required. In this research, submerged moving media was used for a biofilm process and suspended sludge was used for biological nitrogen removal at the same time. In particular DO environment by controlling air flow rate was investigated for simultaneous nitrification/denitrification. Total nitrogen removal in aeration rate more than $67L/min{\cdot}m^3$ showed 51~53% and rose to 65%, 70% and 78% in $50L/min{\cdot}m^3$, $58L/min{\cdot}m^3$ and $25L/min{\cdot}m^3$ respectively. Total phosphorus removal was very low about 10~20% more than $67L/min{\cdot}m^3$ aeration rates. But total phosphorus removal roses when reduces aeration rate by $58L/min{\cdot}m^3$ low and it showed total phosphorus removal of 72% in aeration rate $25L/min{\cdot}m^3$.

• 상하수도학회지
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• 제23권4호
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• pp.439-446
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• 2009

This study was performed to evaluate SND(simultaneous nitrification and denitrification)efficiency, nitrogen removal efficiency and filtration function of non-woven fabric by using submerging MBR packed with granular sulfur covered with non-woven fabric filter. Synthetic wastewater was used as influent wastewater. Concentration of $NH_4{^+}-N$ in influent was maintained about 40 mg/L and the experiment was performed in four phases according to the flow rate. Nitrogen loading rate divided four phases ranging from $0.04 kg\;NH_4{^+}-N/m^3-day$ to $0.16 kg\;NH_4{^+}-N/m^3-day$. As a result, the maximum $NH_4{^+}-N$ removal rate was accomplished at $0.142 kg\;NH_4{^+}-N/m^3-day$ in nitrogen loading of $0.147 kg\;NH_4{^+}-N/m^3-day$. Nitrification efficiency was higher than 95% in all phases. $NO_3{^-}-N$ loading rate was adjusted ranging from $0.22 kg\;NO_3{^-}-N/m^3-day$ to $0.89 kg\;NO_3{^-}-N/m^3-day$. The maximum $NO_3{^-}-N$ removal rate was accomplished up to $0.71 kg\;NO_3{^-}-N/m^3-day$ in $NO_3{^-}-N$ loading of $0.89 kg\;NO_3{^-}-N/m^3-day$. The maximum $NO_3{^-}-N$ removal efficiency was 95% in $NO_3{^-}-N$ loading of $0.22 kg\;NO_3{^-}-N/m^3-day$. T-N removal rate was 90% and concentration of T-N in effluent was 3.7 mg/L in T-N loading rate of $0.039 kg\;NO_3{^-}-N/m^3-day$. In this study, TMP in reactor with and without non-woven fabric filter were observed to define fouling of hollow-fiber membrane module. Reaching time to standard washing pressure(22 cm Hg) of two reactors were 29 days with non-woven fabric But the reactor without non-woven fabric reached standard washing pressure only after 4 days. Accordingly, non-woven fabric was demonstrated the superiority as a filtration ability. With high nitrogen removal rate and decreasing of fouling of membrane, MBR packed with granular sulfur covered with non-woven fabric filter submerging in activated sludge aeration tank can be used as an advanced treatment process.

• 상하수도학회지
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• 제20권4호
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• pp.519-526
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• 2006

In this study, the major operating factors in SND(simultaneous nitrification and denitrification) using bioreactor packed with submerged cilia media and granular sulfur such as variation of nitrification rate, organic matter removal efficiency and denitrification efficiency in different DO concentration were mainly evaluated. Synthetic wastewater and actual sewage were used as influent wastewater. Experiment with synthetic wastewater as influent wastewater was divided into three phases with the adjustment of DO concentration. As the results, nitrification efficiency and T-N removal efficiency in the Phase 3(DO 1.0~2.0 mg/L) were 99% and 52.3%, which is significantly greater than those in other two phases. Also, loading rate and denitrification efficiency of SCPGS(Submerged Cilia media Packed with Granular Sulfur) were calculated as $0.44kg\;NO_3^--N/m^3-day$ and 50%, respectively. On the other hand, nitrification rate was decreased from 99% to 64% according to the DO concentration with the variation from 3.0~3.5 mg/L(phase1) to 0.4~0.6mg/L(phase2). Although the nitrification rate was decreased in 64% according to the variation of the DO concentration, T-N removal rate was rapidly increased to 49% by increasing of the denitrification efficiency. Experiment with actual sewage as influent wastewater was carried out to evaluate efficiency of SCPGS in real operation condition of full-scale sewage water treatment plant. At the time, T-N removal rate in this experiment and full-scale wastewater treatment plants were given by 43% and 20%, respectively. The above results indicate that SCPGS can be used as an advanced treatment process for economical efficiency considered.