수평 흐름형 미생물 연료전지에서 수리학적 체류시간이 전력수율에 미치는 영향

이채영,박수희,우정희,유규선,정재우,송영채 유기성자원학회 2011 유기물자원화 Vol.19 No.1

This study was conducted to investigate the effect of hydraulic retention time(HRT) on the power density in a horizontal flow microbial fuel cell(MFC) reactor. When HRTs were 15min,30min, 60min and 180min, maximum power densities were 24.7 mW/㎡, 27.3 mW/㎡, 22.8mW/㎡ and 17.2 mW/㎡, respectively. The highest power density was obtained at HRT of 30min. It was 59% improvement when compared to the power density at an HRT of 180min. When HRT was increased, COD removal rate increased whereas the coulombic efficiency remained constant. The result shows that the optimal performance of the horizontal flow MFC reactor could be achieved at HRT of 30min. 본 연구에서는 수평 흐름형 미생물 연료전지를 이용하여 수리학적 체류시간에 따른 전력수율을 평가하였다. 수리학적 체류시간 15분, 30분, 60분 및 180분의 경우 전력수율은 각각 24.7 mW/㎡, 27.3mW/㎡, 22.8 mW/㎡ 및 17.2 mW/㎡으로 나타났다. 수리학적 체류시간을 30분으로 유지하는 경우 전력수율이 가장 높게 나타났으며 수리학적 체류시간 180분과 비교시 전력수율이 최대 59% 증가하였다. COD 제거율은 수리학적 체류시간 증가에 따라 높아지는 경향을 보였으나 쿨롱효율은 일정한 값을 유지하였다. 이와 같은 결과를 통해 수리학적 체류시간을 30분으로 유지하는 경우 수평 흐름형 미생물 연료전지성능을 최대로 발휘할 수 있다.

젖소분뇨로부터 최대 바이오가스 생산과 유기물 제거효율을 달성하기 위한 반건식간헐주입 연속혼합 혐기성반응조의 최적 수리학적 체류시간 도출을 위한 연구

강호(Ho Kang),김선우(Sun Woo Kim),정지현(Ji Hyun Jeong),안희권(Hee Kwon Ahn),정광화(Kwang Hwa Jung) 大韓環境工學會 2015 대한환경공학회지 Vol.37 No.12

본 논문은 톱밥 깔개 젖소분뇨 TS 13%를 반건식 간헐주입 연속혼합 반응조(Semi-Continuously Fed and Mixed Reactor, SCFMR)에 주입하여 신재생에너지인 바이오가스의 생산성과 TVS 제거효율을 비교?평가하여 최적 운전조건을 도출하고자하였으며, 그 연구결과를 요약하면 다음과 같다. 톱밥 깔개 젖소분뇨 주입 TS 13%의 반건식 SCFMR의 운전결과 HRT 25일(OLR 4.40~4.50 kg VS/m3-day)에서 최대 바이오가스 발생량 1.44 v/v-d와 CH₄ 발생량 1.12 v/v-d를 달성하였으며, 이 때 TVS제거효율은 바이오가스 발생량 기준 37%이었다. 이는 톱밥 깔개 젖소분뇨 1일 100 kg 주입 시 3.60 m3의 바이오가스를 생산하는 결과이다. 높은 유기물 부하율인 OLR 4.45 kg VS/m3-day (HRT 25일)에서 SCFMR의 운전이 안정적인 이유는 주입시료인 톱밥 깔개 젖소분뇨가 갖고 있는 높은 Alkalinity 농도 때문이다. 그 결과 반응조의 Alkalinity는 14,500~15,600 mg/L as CaCO₃ 범위이었으며, 반응조의 안정성을 평가하는 V/A 비는 평균 0.11, P/A 비는 평균 0.43을 유지하였다. This study was carried out to evaluate the optimum operational condition of Semi-continuously Fed and Mixed Reactor (SCFMR) to treat the dairy cow manure and saw dust mixture. Step-wise increase in organic loading rates (OLRs) or decrease in hydraulic retention times (HRTs) were utilized until the biogas volume became significantly decreased at mesophilic temperature (35℃). The optimum operating condition of the SCFMR fed with TS 13% dairy cow manure and saw dust mixture was found to be an HRTs of 25 days and its corresponding OLRs of 4.45 kg VS/m3-day. At this condition the biogas and methane production rates were 1.44 v/v-d and 1.12 v/v-d (volume of biogas per volume of reactor per day), respectively and the TVS removal efficiency of 37% was achieved. The successful operation with such a high OLR was due to the high reactor alkalinity concentration of 14,500~15,600 mg/L as CaCO₃ as a result of the characteristic of the original substrate, dairy cow manure and saw dust mixture whose alkalinity was more than 8,000 mg/L as CaCO₃. The parameters for the reactor stability, the ratios of volatile acids and alkalinity concentrations (V/A) and the ratio of propionic acid and acetic acid concentrations (P/A) appeared to be 0.11 and 0.43, respectively, that were greatly stable in operation. Free ammonia toxicity was not experienced due to the long term acclimation by the reactor TS content ranged 7.2~10.4% during the entire operational period.

평판형 외기환원전극 미생물연료전지에서 반응기 폭과 수리학적 체류시간이 유기물과 질소 동시 제거에 미치는 영향

박영현(Younghyun Park),유재철(Jaecheul Yu),Evy Widyaningsih,이태호(Taeho Lee) 대한환경공학회 2019 대한환경공학회지 Vol.41 No.2

일실형 미생물연료전지(MFC)는 폭기 및 외부탄소원 비용 없이 유기물과 질소를 동시에 제거할 수 있기 때문에 경제적인 하․폐수처리공정으로 발전할 수 있는 유망한 기술이다. 본 연구에서는 평판형 외기환원전극 MFC의 최적 구조를 평가하기 위하여 3가지 조건의 산화전극부 폭을 선정하였고, 다양한 수리학적체류시간(HRT) 조건에서 유기물 및 질소제거율과 전기 생산량을 평가하였다. 산화전극부 용존산소 농도는 폭이 좁을수록, HRT가 길수록 더 높았다. 최적의 질산화 반응을 위한 HRT는 산화전극부 폭 4 mm는 2시간 이상, 8 mm는 6시간 이상, 16 mm는 8시간이었다. 총질소제거율은 폭 8 mm가 가장 우수했으며(94%), 설계인자인 환원전극 비표면적은 250 m²/m³이었다. 유기물제거율은 모든 조건에서 80% 이상을 나타냈다. 전압은 HRT 2시간에서만 발생하였고, 폭 16 mm, 8 mm, 4 mm 순으로 높게 나타났다. 평판형 외기환원전극 MFC는 구조 및 HRT 조건 변화에 따라, 유기물 및 질소 제거와 전기 생산 등이 가능한 범용성 있는 기술로 발전할 수 있다. A single-chamber microbial fuel cell (MFC) is a promising technology for cost-effective wastewater treatment because it can remove organics and nitrogen simultaneously without aeration and external carbon source. This study evaluated organics and nitrogen removal and electricity production using flat-type air-cathode MFCs with three widths of anode chamber at various hydraulic retention times (HRTs). A shorter width and a longer HRT showed higher dissolved oxygen concentration. For optimum nitrification, the widths of 4 mm, 8 mm and 16 mm required HRTs of >2 h, >6 h and 8 h, respectively. The width of 8 mm (cathode specific surface area of 250 m²/m³ as design factor) showed highest total nitrogen removal efficiency (94%). Removal efficiencies of organics were more than 80% at all conditions. Voltage generation occurred (16 mm > 8 mm > 4 mm) at HRT of 2 h. According to the change of design and HRT conditions, a flat-type air-cathode MFC can be developed as a versatile technology for organics and nitrogen removal and electricity production.

Anaerobic Baffled Reactor 공정을 이용한 1차 슬러지 산발효에 대한 연구

권세영,강민선,김세운,신정훈,최한나,장훈,조진우 대한상하수도학회 2014 상하수도학회지 Vol.28 No.1

A lab-scale Anaerobic Baffled Reactor (ABR) was applied to treat a primary sludge taken from a municipal wastewater treatment plant. In this experiment, acidogenic reaction was promoted by operating the ABR with short hydraulic retention time (HRT) to produce sufficient volatile fatty acids (VFA) instead of production of methane. The performance of ABR on the VFA production and total solids reduction was observed with different operating conditions with 2, 4, 6, and 8 days of HRT. Corresponding organic loading rates were 6.7, 3.4, 2.2, and 1.6 kgCODcr /m3·day. As HRT increased the removal rate of TCOD was also increased (82.5, 84.2, 96.9, and 95.9 % in average for HRT of 2, 4, 6, and 8 days, respectively) because the settlement of solids was enhanced in the baffle by the decrease of upflow velocity. At HRT of 2 days the average concentration of VFA in the effluent was measured at 1,306±552 mgCOD/L corresponding to 107 % increment as compared to the VFA concentration in the influent. However, as HRT increased VFA concentraiotn was decreased to 143±552 mgCOD/L at HRT of 8 days. The reduction rates of total solids were 12.2, 26.5, 24.8, and 43.0 % for HRT of 2, 4, 6, and 8 days. As HRT increased the hydrolysis of organic particulate matters in the reactor was enhanced due to the increasing of solids retention time in the baffle zone with low upflow velocity in long HRT condition. Consequently, we found that a primary sludge became a good source of VFA production by the application of ABR process with HRT less than 4 days and the 12-26 % of total solids reduction was expected at these conditions.

슬러지 호기성 소화공정에서의 유기물 분해 및 질산화 특성

황응주(Eung Ju Hwang) 大韓環境工學會 2009 대한환경공학회지 Vol.31 No.10

슬러지의 감량과 최종처분 기술 개발을 위해 실험실 규모 호기성 소화공정을 279일간 운전하였다. 혐기성 소화 슬러지를 원료로 40℃에서 120분간 알칼리 전처리하여 호기성 소화조에 유입시켰다. 유입 슬러지 성상과 HRT의 변화에 따라 소화효율의 변화가 있었으며 적정 HRT는 6일인 것으로 나타났다. 이때 NH₃-N, SCOD, TKN, TCOD, SS, VSS의 평균 제거율(소화조 유입 슬러지 기준)은 각각 97.4%, 81.7%, 68.7%, 61.4%, 50.6%, 47.0% 이었다. SS는 전처리와 호기성 소화를 통해 원료 슬러지(23,920 mg/L)의 73.9% 감량화가 가능하였다. 처리 슬러지는 약 350 mg/L의 SCOD를 포함하고 있어 액비로 활용하기에 무리가 없을 것으로 판단되었다. HRT를 5일 이상으로 유지할 경우 질산화 반응이 활성화되었으며 최대 658 mg/L의 유출 슬러지 질산성 질소 농도를 얻을 수 있었다. 암모니아성 질소 농도는 20 mg/L 내외로 크게 감소하였다. Continuous operation of aerobic sludge digestion reactor was attempted for 279 days. Anaerobic digester sludge, the target material of the experiment, was pretreated by sodium hydroxide at 40℃ for 120 minutes, and the pretreated sludge was fed to 5 L CSTR (continuous stirred tank reactor). Reactor performance was affected by properties of input sludge and HRT (hydraulic retention time). 6 days of HRT showed best and stable performance, and under this condition, removal rates of NH₃-N, SCOD, TKN, TCOD, SS, and VSS were 97.4%, 81.7%, 68.7%, 61.4%, 50.6%, and 47.0%, respectively. 73.9% of SS in anaerobic digester sludge was reduced by pretreatment and aerobic digestion. Effluent sludge had low soluble COD of 350 mg/L. This implied the sludge was stabilized and suitable for use as liquid fertilizer. Nitrification took place when HRT was higher than 4 days. NO₃-N concentration was as high as 658 mg/L while NH₃-N was as low as 20 mg/L.

정수지 내 추적자 실험과 CFD(전산유체역학)의 상관관계 분석

김태균,최영준,조영만 대한상하수도학회 2011 상하수도학회지 Vol.25 No.5

Hydraulic efficiency was a vital component in evaluating the disinfection capability of clearwell. Current practice evaluates these system based on the tracer test only. In this paper, CFD(Computational Fluid Dynamics) was applied on the clearwell for alternating or supplementing the tracer test. The baffle factor derived from the CFD modeling closely matched the values obtained from full scale tracer testing. And, for suggesting proper numerical model in clearwell; the turbulence model, discretization scheme, convergence criteria were investigated through separate simulation runs. The model validation was conducted by comparing the simulated data with experimental data. In the turbulence model, the realizable κ-ε model and the standard κ-ε model were found to be more appropriate than RNG κ-ε model. The residuals of convergence criteria should be used as not 10^(-3) but 10^(-4) or 10^(-5). In discretization scheme, the difference of simulated value in 1st, 2nd, 3rd upwind scheme were found to be insignificant. Moreover, the result of this study suggest that CFD modeling can be a reliable alternative to tracer testing for evaluating the hydraulic efficiency.

혐기조의 인 방출 최적화를 위한 영향인자 평가

허형우(Heo Hyeong U),신경숙(Sin Gyeong Sug),박승국(Park Seung Gug),박종부(Park Jong Bu),최은주(Choe Eun Ju),강호(Kang Ho) 大韓環境工學會 2003 대한환경공학회지 Vol.25 No.11

Two-sludge 유형 SBR 공정의 최적 운영 조건 도출

류홍덕(Hong Duck Ryu),황재식(Jae Sik Hwang),김금용(Keum Yong Kim),이상일(Sang Ill Lee) 大韓環境工學會 2007 대한환경공학회지 Vol.29 No.2

제올라이트를 첨가한 질산화 탈질공정에서 수리학적 체류시간이 호기조내 Bound EPS 및 SMP 농도에 미치는 영향

윤태일(Tai Il Yoon),이탄우(Tan Woo Lee),조경철(Kyung Chul Cho),이형술(Hyung Sool Lee) 大韓環境工學會 2004 대한환경공학회지 Vol.26 No.10

다공성 Zeolite-Slag 세라믹 충진 컬럼을 이용한 일광광산 산성광산배수의 처리에 미치는 영향인자 및 운전조건 연구

이영남 ( Yeong-nam Lee ),임수빈 ( Soo-bin Yim ) 한국수처리학회(구 한국수처리기술연구회) 2021 한국수처리학회지 Vol.29 No.1

This study was performed to identify the influencing factors and operating conditions on the treatment of acid mine drainage(AMD) from the Il-kwang mine by porous Zeolite-Slag(ZS) ceramics packed in a column reactor. The hydraulic retention time(HRT) of the column reactor was a pivotal operating condition. Additionally, the mixing ratio of zeolite to slag (Z:S) significantly affected the column’s alkali supply capacity and heavy metal removal efficiency. An HRT of 1.0 day was more effective than 0.5 day HRT in terms of alkali supply capacity and heavy metal removal efficiency. The heavy metal removal efficiency of the 1:3 (Z:S) porous ZS ceramics was higher than that of the 1:1 (Z:S). The average heavy metal removal efficiencies of the 1:3 (Z:S) in a continuous column reactor (1.0 day HRT, 31 operating days) were 92.4%, 86.3%, 96.5%, 99.2%, 96.1%, 89.3%, 98.9% and 93.7%, for Al, As, Cd, Cu, Fe, Mn, Pb, and Zn, respectively. These results suggest that a porous 1:3 (Z:S) ceramic column reactor at an HRT of 1.0 day might be an effective long-term treatment strategy for AMD from the Il-kwang mine.