• Environmental Engineering Research
• /
• 제17권2호
• /
• pp.59-63
• /
• 2012

This paper proposes a modified Ludzack-Ettinger (MLE) type membrane bioreactor (MBR) as a method of treatment for wastewater from food waste disposer. Micro-membrane filtration allows for an extremely low concentration of suspended solids in the effluent. The effluent of the reactor in question is characterized by a relatively high level of non-biodegradable organics, containing a substantial amount of soluble microbial products and biomass. Results obtained in this paper by measurement of membrane fouling are consistent with biomass concentration in the reactor, as opposed to chemical oxygen demand (COD). The MLE process is shown to be effective for the treatment of wastewater with a high COD/N ratio of 20, resulting in are markedly high total nitrogen removal efficiency. Denitrification could be improved at a higher internal recycle ratio. Despite the low concentration of influent phosphorus, the phosphorus concentration of the outflow is seen to be relatively high. This is because outflow phosphorous concentration is related to COD consumption, and the process operates at along solids retention time.

• 한국물환경학회지
• /
• 제22권1호
• /
• pp.7-16
• /
• 2006

The present study evaluated effect of temperature on removals of organic matter (C), nitrogen (N) and phosphorus (P) in Modified-Dephanox (M-Dephanox) process, which is hybrid system, comparing with those of Modified-Ludzack Ettinger (MLE) under the suspended-growth bacteria, as control. M-Dephanox process was more stable than MLE process in the removal of C, N, P, especially in nitrification, as the temperature was decreased from $25^{\circ}C$ to $16^{\circ}C$. As the temperature was decreased from $25^{\circ}C$ to $16^{\circ}C$, the removal efficiency of $NH_4{^+}-N$ of M-Dephanox process was decreased by 3.8%, but that of MLE process decreased by 25.7%. T-N removal efficiency of M-Dephanox was higher than MLE process by 27.1% and 26.9% at $25^{\circ}C$ and $16^{\circ}C$ of temperature, respectively.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2002년도 생물공학의 동향 (X)
• /
• pp.399-402
• /
• 2002

Industrial wastewater with high ammonium concentration was treated in batch biological systems which was a modified Ludzack- Ettinger process. Up to 78% conversion of $NH_4\;^+-N$ to $NO_x\;^--N$ was achieved in batch culture condition. Under anoxic condition with methanol as the carbon source, the denitrifiers decreased $NO_x\;^--N$ concentration from 608 mg/L to 5.6 mg/L in 22 d. As well as anoxic denitrification of $NO_x\;^-$ to $N_2$, dissimilatory nitrate reduction to ammonium also occurred under the condition as respiratory denitrification.

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

• 대한환경공학회지
• /
• 제28권1호
• /
• pp.15-25
• /
• 2006

본 연구는 도시하수 처리시 부유성장 미생물만을 이용하는 MLE(Modified Ludzack-Ettinger) 공정과 부유 및 부착 미생물을 동시에 활용하는 하이브리드(hybrid)형 공정인 M-Dephanox(Modified-Dephanok) 공정의 유기물, 질소 및 인 제거효율을 수리학적 체류시간에 따라 상호 비교 검토하고자 하였다. H-Dephanox 공정은 기존 Dephanox 공정의 단점을 극복하기 위하여 고안된 공정으로서 기존 Dephanox 공정에 비해 탈질 효율을 증가시킬 수 있도록 고안되었다. 수리학적 체류시간에 따른 유기물, 질소 및 인 제거효율을 관찰한 결과 하이브리드 공정인 H-Dephanox 공정이 MLE 공정에 비해 높은 제거효율이 관찰되었으며, 특히 질산화의 경우 수리학적 체류시간이 6, 5, 4, 3.5 hr으로 짧아짐에 따라 MLE 공정이 M-Dephanox 공정에 비해 질산화 영향을 더 심하게 받는 것으로 나타났다. M-Dephanox 공정의 질화반응조에서의 암모니아성 질소 제거 효율은 질산화 반응조의 HRT 1.59 hr에서 약 92%를 나타내 매우 짧은 수리학적 체류시간에서도 질산화 반응이 원활하게 일어나는 것을 관찰 할 수 있었으며, 질산화 반응조로 유입되는 유기물의 영향을 심하게 받는 것으로 관찰되었다. 질산화 반응조에서의 HRT 단축은 전체 공정의 HRT도 줄이는 결과를 가져옴을 관찰 할 수 있었다.

• 한국환경과학회지
• /
• 제27권2호
• /
• pp.99-107
• /
• 2018

In order to design the improvement process for T-N removal, the treatment process of Suyoung, Gangbyeon, and Noxan sewage treatment plants (STP) in Busan was anlayzed. Suyoung STP shows a T-N removal efficiency of about 69.8% with MLE(Modified Ludzack ettinger) and A2O+MBR. However, it is necessary to improve the process to maintain over DO of 1 mg/L and is required to install a flow control tank to minimize the rainfall effect. Gangbyun STP shows a about 70.2% T-N removal efficiency with A2O+GFF(gravity fiber filtration). However, in order to improve T-N removal efficiency, it is needed to install MLE process to treat recycle water. Noksan STP shows a T-N removal efficiency of about 71.0% with MLE+Chemical treatment and shows stable T-N concentration in effluent. However, it is required a toxic chemical management process because bad wastewater flows into the STP, also is necessary a process improvement in order to increase internal recycling ratio. Especially, it is required a process improvement to increase HRT of nitrification tank because Suyoung and Gangbyeon STPs shows low nitrification efficiency during winter season.

• 한국물환경학회지
• /
• 제22권5호
• /
• pp.895-904
• /
• 2006

The improved MLE (modified Ludzack-Ettinger) process was operated for piggery waste treatment in full-scale public livestock waste treatment plant. The treated waste from bioreactor was suitable for the strict effluent standard of 200 mgCOD/L and 60 mgTN/L as it was dewatered chemically without settling tank and passed through filtration process. Though this treatment method produced a great deal of sludge ($6.4m^3\;per\;m^3$ dewatered piggery waste) it was able to accomplish predominant effluent quality by removing non-biodegradable COD and color without advanced oxidation process as ozone, fenton and etc.. The nitrogen removal efficiency of bioreactor was rapidly declined from March to May (from 0.016 to 0.005 kgN/kgVSS-day) when disinfection is in earnest as well as from warm season when reactor temperature rises higher than $35^{\circ}C$(from 0.016 to 0.008 kgN/kgVSS-day). This study proves that counterplanes for infection residuals, bioreactor temperature and dewatering sludge reduction are necessary for piggery waste treatment.

• 상하수도학회지
• /
• 제14권2호
• /
• pp.147-156
• /
• 2000

In this study, the optimal operation parameters of MLE(Modified Ludzack-Ettinger) process treating the liquid supernatant separated from the slurry excreta of swine feedlot was studied as a promising biological treatment process. The nitrogen removal characteristics with different volume ratio between nitrification and denitrification reactor and the operational effect with different nitrogen loading rate, and different C/N($COD_{Cr}/TKN$) ratio were investigated. Based on the laboratory results, pilot MLE plant was operated to examine the effect of ambient temperature for five months including winter. The denitrification reactor which is 20% of total volume was proposed as the most optimal volume fraction for nitrification and denitrification. The optimum ratios of F/M and $F_N/M$ were increased with increase of the C/N ratio. However, optimum F/M ratio was changed more rapidly than $F_N/M$ ratio with increase of the C/N ratio. Therefore, MLE process is desirable to be controlled by F/M ratio in the range of high C/N ratio and by $F_N/M$ ratio in the range of low C/N ratio. Pilot MLE plant showed the higher removal efficiencies of COD and TKN in winter than in summer and was operated most stably at the temperature of $20{\sim}25^{\circ}C$ for mixed liqour.

• 상하수도학회지
• /
• 제21권5호
• /
• pp.521-529
• /
• 2007

Nutrient removal from synthetic wastewater was investigated using a MLE (Modified-Ludzack Ettinger) type MBBR (Moving Bed Biofilm Reactor), with different phenol ($C_6H_5OH$) concentrations, in order to determine the inhibition effects of phenol on biological nutrient removal and the biodegradation of phenolic wastewater. The wastewater was prepared by mixing a solution of molasses with known amounts of phenol and nutrients. The experiments were conducted in a lab-scale MLE type MBBR, operated with four different phenol concentrations (0, 67, 100 and 168mg/L) in the synthetic feed. Throughout the experiments, the ratio of the phenolic COD concentration to the total COD was varied from 0 to 1. Throughout batch test, the SNR (Specific Nitrification Rate) and SDNR (Specific Denitrification Rate) were significantly influenced by changes of the phenol concentration. Phenol was inhibitory to the nitrification/denitrification process, and showed greater inhibition with higher initial phenol concentrations. The SNR observed with 0, 67, 100 and 168mg phenol/L were very different like 10.12, 6.95, 1.51 and $0.35mg\;NH_{3^-}N/gMLVSS$ hr, respectively. Similarly, the SDNR observed at 0, 67, 100 and 168mg phenol/L were different like 0.322, 0.143, 0.049and 0.006mgN/gMLVSS day, respectively.

• 한국환경과학회지
• /
• 제21권12호
• /
• pp.1449-1454
• /
• 2012

The ion selective microelectrodes (ISME) have been applied to observe the continuous profiles of NO3-N and NH4-N in bulk solutions or biofilms. In order to evaluate the performance and applicability of ion concentration measuring system, the characteristics, such as slope of calibration curve, detection limit and potentiometric selectivity coefficient were investigated. The slopes of calibration curve showed high degree of correspondence for each target ion concentrations. And the detection limits of nitrate and ammonia ion selective microelectrode were 10-4.7 M and 10-4.4 M, respectively. These ion selective microelectrodes were proved that their own performance could be maintained for 16 days after making. NO3-N and NH4-N selective microelectrodes were also adapted to detect the continuous ion profiles of cilia media packed MLE (Modified Ludzack-Ettinger) process. And the monitored nitrate and ammonia ion profiles with the ion selective microelectrode were stable and well corresponded to the results with conventional ion chromatograph. However, the electric potential was unstable until 8 hr because of the unknown noise. The tip shape and performance of the ion selective microelectrode was stably kept over 2 days continuous monitoring.