Effect of gradual transition of substrate on performance of flat-panel air-cathode microbial fuel cells to treat domestic wastewater

Park, Younghyun,Park, Seonghwan,Nguyen, Van Khanh,Kim, Jung Rae,Kim, Hong Suck,Kim, Byung Goon,Yu, Jaecheul,Lee, Taeho Elsevier 2017 Bioresource technology Vol.226 No.-

<P><B>Abstract</B></P> <P>In order to confirm the effects of the low conductivity and biodegradability of wastewater, flat-panel air-cathode microbial fuel cells (FA-MFCs) were operated by supplying substrates with different volume ratios of domestic wastewater mixed with an artificial medium: the artificial medium only, 25% wastewater, 50% wastewater, 75% wastewater, 100% of wastewater with 500mg-COD/L by adding acetate, and raw domestic wastewater (230mg-COD/L). With the increase of wastewater ratio, the maximum power density and organic removal efficiency decreased from 187 to 60W/m<SUP>3</SUP> and 51.5 to 37.4%, respectively, but the Coulombic efficiency was maintained in the range of 18.0–18.9%. The FA-MFCs could maintain their low internal resistances and overcome the decreasing conductivity. The acetate concentration was more important than the total organics for power production. This study suggests that the FA-MFC configuration has great applicability for practical applications when supplied by domestic wastewater with low conductivity and biodegradability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> FA-MFCs were operated by substrate transition from acetate to domestic wastewater. </LI> <LI> Coulombic efficiency in acetate was similar to that in domestic wastewater. </LI> <LI> Maximum power density had higher correlation with acetate than with COD. </LI> <LI> FA-MFCs could maintain low internal resistance and overcome decreasing conductivity. </LI> </UL> </P>

Effects of anode spacing and flow rate on energy recovery of flat-panel air-cathode microbial fuel cells using domestic wastewater

Park, Younghyun,Nguyen, Van Khanh,Park, Seonghwan,Yu, Jaecheul,Lee, Taeho Elsevier 2018 Bioresource technology Vol.258 No.-

<P><B>Abstract</B></P> <P>A flat-panel air-cathode microbial fuel cell (FA-MFC) is known to overcome the low conductivity and biodegradability of domestic wastewater. This study evaluated the normalized energy recovery (NER) based on the volume of wastewater treated (NER<SUB>V</SUB>) and chemical oxygen demand (COD) removal (NER<SUB>COD</SUB>) using FA-MFCs with three anode spacing conditions and different flow rates (within a hydraulic retention time of 30 min). Generation of current was similar (11.7 ± 0.5 mA) at different spacings; however, COD removal was affected by the flow rates. The NER<SUB>V</SUB> for both acetate and domestic wastewater showed good agreements with the flow rates in all anode spacing conditions. The NER<SUB>COD</SUB> results were negatively correlated with the COD removal rates, independent of the anode spacing. The FA-MFCs yielded an NER<SUB>COD</SUB> of 0.22 kWh/kg-COD from extremely low-strength domestic wastewater (150 mg-COD/L). The FA-MFC has a significant potential as an energy-sustainable wastewater treatment technology.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The FA-MFC with shortest anode spacing produced the highest electrical energy. </LI> <LI> NER<SUB>V</SUB> showed a negative correlation with flow rate in all anode spacings. </LI> <LI> NER<SUB>COD</SUB> was correlated with COD removal rate, independent of anode spacing. </LI> <LI> The FA-MFC has a great potential to recover energy from low-strength wastewater. </LI> </UL> </P>

Response of microbial community structure to pre-acclimation strategies in microbial fuel cells for domestic wastewater treatment

Park, Younghyun,Cho, Hyunwoo,Yu, Jaechul,Min, Booki,Kim, Hong Suck,Kim, Byung Goon,Lee, Taeho Elsevier 2017 Bioresource technology Vol.233 No.-

<P><B>Abstract</B></P> <P>Microbial community structures and performance of air-cathode microbial fuel cells (MFCs) inoculated with activated sludge from domestic wastewater were investigated to evaluate the effects of three substrate pre-acclimation strategies: 1, serial pre-acclimation with acetate and glucose before supplying domestic wastewater; 2, one step pre-acclimation with acetate before supplying domestic wastewater; and 3, direct supply of domestic wastewater without any pre-acclimation. Strategy 1 showed much higher current generation (1.4mA) and Coulombic efficiency (33.5%) than strategies 2 (0.7mA and 9.4%) and 3 (0.9mA and 10.3%). Pyrosequencing showed that microbial communities were significantly affected by pre-acclimation strategy. Although <I>Proteobacteria</I> was the dominant phylum with all strategies, <I>Actinobacteria</I> was abundant when MFCs were pre-acclimated with glucose after acetate. Not only anode-respiring bacteria (ARB) in the genus <I>Geobacter</I> but also non-ARB belonging to the family <I>Anaerolinaceae</I> seemed to play important roles in air-cathode MFCs to produce electricity from domestic wastewater.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Three strategies were applied for substrate pre-acclimation of air-cathode MFCs. </LI> <LI> Serial pre-acclimation with acetate-glucose produced higher current from wastewater. </LI> <LI> Microbial communities were significantly varied by pre-acclimation strategies. </LI> <LI> <I>Anaerolinaceae</I> seemed to play important roles in MFCs using domestic wastewater. </LI> </UL> </P>

Complete nitrogen removal by simultaneous nitrification and denitrification in flat-panel air-cathode microbial fuel cells treating domestic wastewater

Park, Younghyun,Park, Seonghwan,Nguyen, Van Khanh,Yu, Jaecheul,Torres, Cé,sar I.,Rittmann, Bruce E.,Lee, Taeho Elsevier 2017 Chemical engineering journal Vol.316 No.-

<P><B>Abstract</B></P> <P>Microbial fuel cells (MFCs) can treat organic compounds from domestic wastewater without aeration, but an additional procedure is required to remove nitrogen. This study developed a flat-panel air-cathode MFC (FA-MFC) that was comprised of five MFC units connected in series and operated to remove organic and nitrogen compounds from domestic wastewater with a short hydraulic retention time (HRT) of 2.5h. During eight months of operation, the removal efficiencies of chemical oxygen demand (COD) and total nitrogen (TN) increased, reaching 85% and 94%, respectively, and the effluent COD and TN concentrations were 20.7±2.5mg/L and 1.7±0.1mg/L, respectively. The greatest removals of COD and TN were in the first and second unit (0.62kg-N/m<SUP>3</SUP>/d of TN removal rate). The FA-MFC system allowed simultaneous removals of COD and TN from domestic wastewater, although it led to minimal power output (6.3W/m<SUP>3</SUP> in the first unit). Because any abiotic ammonia loss was not found under the supplied potential of∼1.1V at a short HRT of 30min, the biological nitrogen removal was thought as a dominant mechanism for TN removal in the FA-MFCs. Microbial community analysis revealed that, near the cathode, <I>Nitrosomonas</I>-like strains contributed to nitrification and <I>Nitratireductor</I>-like strains led to denitrification. <I>Acidovorax</I>-like strains, known for their metabolic diversity, were ubiquitous and appeared to contribute to organics and nitrogen removal in anode and cathode biofilms. This study provides proof of concept that the FA-MFC system has a promise for energy sustainable wastewater treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> FA-MFC system for domestic wastewater treatment was operated during 8months. </LI> <LI> FA-MFCs could successfully satisfy COD and TN discharge limits at an HRT of∼2.5h. </LI> <LI> FA-MFC system showed a significantly high TN removal rate up to 0.62kg-N/m<SUP>3</SUP>/d. </LI> <LI> <I>Nitrosomonas</I>, <I>Nitratireductor</I> and <I>Acidovorax</I> spp. contributed to nitrogen removal. </LI> <LI> FA-MFC system has a promise for energy-sustainable domestic wastewater treatment. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Comparison of batch cultivation strategies for cost-effective biomass production of <i>Micractinium inermum</i> NLP-F014 using a blended wastewater medium

Park, Seonghwan,Kim, Jeongmi,Park, Younghyun,Son, Suyoung,Cho, Sunja,Kim, Changwon,Lee, Taeho Elsevier 2017 Bioresource technology Vol.234 No.-

<P><B>Abstract</B></P> <P>Two competitive strategies, fed-batch and sequencing-batch cultivation, were compared in cost-effective biomass production of a high lipid microalgae, <I>Micractinium inermum</I> NLP-F014 using a blended wastewater medium. For fed-batch cultivations, additional nutrient was supplemented at day 2 (FB1) or consecutively added at day 2 and 4 (FB2). Through inoculum size test, 1.0g-DCWL<SUP>−1</SUP> was selected for the sequencing-batch cultivation (SB) where about 65% of culture was replaced with fresh medium every 2days. Both fed-batch cultivations showed the maximum biomass productivity of 0.95g-DCWL<SUP>−1</SUP> d<SUP>−1</SUP>, while average biomass productivity in SB was slightly higher as 0.96±0.08g-DCWL<SUP>−1</SUP> d<SUP>−1</SUP>. Furthermore, remained concentrations of organics (426mg-CODL<SUP>−1</SUP>), total nitrogen (15.4mg-NL<SUP>−1</SUP>) and phosphorus (0.6mg-PL<SUP>−1</SUP>) in SB were much lower than those of fed-batch conditions. The results suggested that SB could be a promising strategy to cultivate <I>M. inermum</I> NLP-F014 with the blended wastewater medium.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A valuable strategy for cost-effective production of <I>M. inermum</I> was determined. </LI> <LI> Two batch cultivation strategies, fed-batch and sequencing-batch mode, were tested. </LI> <LI> Culture medium was a mixture of domestic WW and aerobically digested swine WW. </LI> <LI> The highest biomass productivity was obtained from the sequencing-batch mode. </LI> <LI> The sequencing-batch mode also showed low environmental impacts. </LI> </UL> </P>

Vitamin C Inhibits Visceral Adipocyte Hypertrophy and Lowers Blood Glucose Levels in High-Fat-Diet-Induced Obese C57BL/6J Mice

Younghyun Park,Joonseong Jang,Dongju Lee,Michung Yoon 대한의생명과학회 2018 Biomedical Science Letters Vol.24 No.4

Vitamin C (ascorbic acid) supplementation has been suggested to negatively correlate with obesity in humans and other animals. Previous studies, including ours, have demonstrated that a high-fat diet (HFD) induces obesity and related diseases such as hyperlipidemia, hyperglycemia, insulin resistance, and nonalcoholic fatty liver disease. Here, we investigated the effects of vitamin C on visceral adipocyte hypertrophy and glucose intolerance in C57BL/6J mice. Mice received a low-fat diet (LFD, 10% kcal fat), HFD (45% kcal fat), or the same HFD supplemented with vitamin C (HFD-VC, 1% w/w) for 15 weeks. Visceral adiposity and glucose intolerance were examined using metabolic measurements, histology, and gene expression analyses. Mice in the HFD-VC supplementation group had reduced body weight, mesenteric fat mass, and mesenteric adipocyte size compared with HFD-fed mice. Vitamin C intake in obese mice also decreased the mRNA levels of lipogenesis-related genes (i.e., stearoyl-CoA desaturase 1 and sterol regulatory element-binding protein 1c) in mesenteric adipose tissues, inhibited hyperglycemia, and improved glucose tolerance. In addition, vitamin C attenuated the HFD-induced increase in the size of pancreatic islets. These results suggest that vitamin C suppresses HFD-induced visceral adipocyte hypertrophy and glucose intolerance in part by decreasing the visceral adipose expression of genes involved in lipogenesis.

Antiplatelet Constituent Isolated from Thujopsis dolabrata var. hondai

Park YoungHyun,Yun YeoPyo,Won EunKyung,Lee SungEun,Park ByeoungSoo,Son DongJu 大韓藥學會 2003 大韓藥學會 總會 및 學術大會 Vol.2003 No.1

미생물전기화학기술을 이용한 하수방류수기준 만족 유기물/질소 동시 제거

박영현 ( Younghyun Park ),응웬반칸 ( Vankhanh Nguyen ),이태호 ( Taeho Lee ) 한국물환경학회(구 한국수질보전학회) 2016 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2016 No.-

CFD-CSD 연성 연계 기법을 이용한 LCH 로터의 공력/구조 하중 예측

유영현(Younghyun You),정성남(Sung Nam Jung),김기로(Kiro Kim),박수형(Soo Hyung Park),박구환(Gu Hwan Park) 한국항공우주학회 2017 한국항공우주학회 학술발표회 논문집 Vol.2017 No.11

침지형 미생물연료전지에서 유입 COD 및 HRT 변화가 하수 수준의 질소 제거에 미치는 영향

박영현(Younghyun Park),양희천(Heechun Yang),유재철(Jaecheul Yu),이태호(Taeho Lee) 대한환경공학회 2018 대한환경공학회지 Vol.40 No.8

침지형 미생물연료전지(MFC)는 하수처리공정에 쉽게 적용할 수 있는 구조이지만, 질소 제거에 대한 연구는 아직 부족한 실정이다. 본 연구에서는 4개의 유닛으로 구성된 침지형 MFC 시스템을 이용하여 기질의 종류 및 농도와 HRT에 따른 COD 및 TN 제거율, 에너지 회수를 평가하였다. 유기물 제거를 위한 최적 HRT는 모든 기질 조건에서 6시간이었고, 아세트산 500 mg-COD/L는 78%, 150 mg-COD/L는 89%, 글루코스 150 mg-COD/L는 76%가 제거되었다. 하수 수준의 질소 농도(40 mg-N/L) 제거를 위한 최적 HRT는 아세트산은 3시간, 글루코스는 8시간이었고, 우리나라 하수처리시설의 TN 방류수 수질기준(<20 mg-N/L)을 만족시켰으며, 이때의 질소 제거속도는 72-192 g-N/m³/d이었다. 침지형 MFC의 에너지 회수량은 모든 조건에서 0.004 kW/kg-COD 이하로 나타났지만, 질소 제거에 소비되는 추가 에너지가 없기 때문에, 향후 에너지 중립적인 하수처리공정으로 발전시킬 수 있을 것으로 기대된다. Submerged-type microbial fuel cells (MFCs) have been developed to cost-effectively treat organics in wastewater. However, evaluation of nitrogen removal in MFCs is still limited to apply MFCs for domestic wastewater treatment. This study developed submerged MFC system consisting of 4 units and evaluated COD and TN removal efficiencies and energy recovery according to substrate type and concentration and HRT. The organic removal efficiencies were 78% (500 mg-COD/L), 89% (150 mg-COD/L of acetate) and 76% (150 mg-COD/L of glucose) at the optimal HRT of 6 h. Submerged MFC system for removal of low-strength nitrogen (40 mg-N/L) could satisfy the TN discharge limit (<20 mg-N/L) and the nitrogen removal rates of 72-192g-N/m³/d at the optimal HRTs of 3 h (acetate) and 8 h (glucose). Because additional energy for nitrogen removal is not required, despite low energy recoveries (<0.004 kW/kg-COD), it is expected that the submerged MFC system can be applied as the energyneutral domestic wastewater treatment process.