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Shin SR, Im S, Mostafa A, Lee MK, Yun YM, Oh SE, Kim DH. Effects of pig slurry acidification on methane emissions during storage and subsequent biogas production. Water Res 2019; 152:234-240. [PMID: 30677634 DOI: 10.1016/j.watres.2019.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 12/24/2018] [Accepted: 01/13/2019] [Indexed: 06/09/2023]
Abstract
In addition to undesirable odorous gases, substantial amounts of greenhouse gases (GHG), particularly methane (CH4), are generated during the storage of livestock manure. To reduce the CH4 emissions, first, pig slurry (PS) was stored for 40 d at 30 °C after adjusting the pH at 5.0-7.0 using H2SO4 solution. In the control (non-acidified PS), 3.7 kg CO2 eq./ton PS of CH4 emissions was detected, which was reduced to 1.8, 0.9, 0.4, 0.2, and 0.1 kg CO2 eq./ton PS at pH 7.0, 6.5, 6.0, 5.5, and 5.0, respectively. Methanosarcina was found to be the dominant genus (67% of the total archaeal sequence) in the control, whose dominance was reduced as storage pH decreased. The results of ribonucleic acid analysis and specific methanogenic activity test further confirmed the inhibition of indigenous methanogens by acidification. Later, the biochemical CH4 potential of stored PS was tested. Compared to the control (10.6 L CH4/L PS), the acidified PS showed higher CH4 yields of 12.7-14.6 L CH4/L PS, presumably by keeping degradable organic matters in PS under acidic condition. Among different acidification pHs tested, the maximum amount of GHG reduction was achieved at pH 6.0 by reducing CH4 emission to +0.4 kg CO2 eq./ton PS during storage while increasing biogas production potential equivalent to 48.3 kWh/ton PS (-22.5 kg CO2 eq./ton PS), resulting in a further reduction of (-)9.6 kg CO2 eq./ton PS compared to the control.
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Affiliation(s)
- Sang-Ryong Shin
- Department of Civil Engineering, Inha University, 100 Inharo, Nam-gu, Incheon, 22212, Republic of Korea
| | - Seongwon Im
- Department of Civil Engineering, Inha University, 100 Inharo, Nam-gu, Incheon, 22212, Republic of Korea
| | - Alsayed Mostafa
- Department of Civil Engineering, Inha University, 100 Inharo, Nam-gu, Incheon, 22212, Republic of Korea
| | - Mo-Kwon Lee
- Department of Civil Engineering, Inha University, 100 Inharo, Nam-gu, Incheon, 22212, Republic of Korea
| | - Yeo-Myeong Yun
- Department of Environmental Engineering, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju, Chungbuk, 28644, Republic of Korea
| | - Sae-Eun Oh
- Department of Civil and Environmental Engineering, Hanbat National University, 125 Dongseodaero, Yuseong-gu, Daejeon, 305-719, Republic of Korea
| | - Dong-Hoon Kim
- Department of Civil Engineering, Inha University, 100 Inharo, Nam-gu, Incheon, 22212, Republic of Korea.
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Cho SK, Kim DH, Quince C, Im WT, Oh SE, Shin SG. Low-strength ultrasonication positively affects methanogenic granules toward higher AD performance: Implications from microbial community shift. Ultrason Sonochem 2016; 32:198-203. [PMID: 27150761 DOI: 10.1016/j.ultsonch.2016.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/08/2016] [Accepted: 03/08/2016] [Indexed: 06/05/2023]
Abstract
To elucidate the enhanced methane yield from organic wastes, the effects of low-strength ultrasonication on the microbial community structures in upflow anaerobic sludge blanket reactors were for the first time analyzed using pyrosequencing. Interestingly, a more even microbial community was observed in the ultrasonicated granules than in the control, which could compensate for the decreased richness and resulted in comparable (archaea) or even higher (bacteria) diversity. The ultrasonicated granules contained higher levels of δ-Proteobacteria, of which many are reportedly potential syntrophs, as well as methanogenic genera Methanosaeta, Methanotorris, and Methanococcus. The increased presence of syntrophic bacteria with their methanogenic partners was discussed with respect to hydrogen flux; their selective proliferation seems to be responsible for the enhanced anaerobic performance. This study is the first research shedding light on the novel function of low-strength ultrasound shifting the microbial structure towards better biogas production performance, and will facilitate application of low-strength ultrasound to other bioprocesses.
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Affiliation(s)
- Si-Kyung Cho
- Department of Biological and Environmental Science, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang, Gyeonggi-do, Republic of Korea
| | - Dong-Hoon Kim
- Department of Civil Engineering, Inha University, 100 Inha-ro, Nam-gu, Incheon, Republic of Korea
| | | | - Wan-Taek Im
- Department of Biotechnology, Hankyong National University, 327 Chungang-no, Anseong, Gyeonggi-do, Republic of Korea
| | - Sae-Eun Oh
- Department of Environmental Engineering, Hanbat National University, San 16-1, Duckmyoung-dong, Yuseong-gu, Daejeon, Republic of Korea
| | - Seung Gu Shin
- School of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Pohang, Gyeongbuk, Republic of Korea.
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Kim DH, Lee MK, Moon C, Yun YM, Lee W, Oh SE, Kim MS. Effect of hydraulic retention time on lactic acid production and granulation in an up-flow anaerobic sludge blanket reactor. Bioresour Technol 2014; 165:158-161. [PMID: 24767539 DOI: 10.1016/j.biortech.2014.03.097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 03/04/2014] [Accepted: 03/06/2014] [Indexed: 06/03/2023]
Abstract
In the present work, lactic acid (LA) production performance with granulation was investigated at various hydraulic retention times (HRTs), 8-0.5h. Glucose was used as a feedstock, and anaerobic mixed cultures were inoculated in an up-flow anaerobic sludge blanket reactor. As HRT decreased, the average diameter and hydrophobicity of the granules increased from 0.31 to 3.4mm and from 17.5% to 38.3%, respectively, suggesting the successful formation of granules. With decreasing HRT, LA productivity increased up to 16.7gLA/L-fermenter/h at HRT 0.5h. The existence of rod-shaped organisms with pores and internal channels at granule surface was observed by scanning electron microscope. Next generation sequencing revealed that Lactobacillus was the dominant microorganism, accounting for 96.7% of total sequences, comprising LA-producing granules.
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Affiliation(s)
- Dong-Hoon Kim
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea
| | - Mo-Kwon Lee
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea
| | - Chungman Moon
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea
| | - Yeo-Myeong Yun
- Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Wontae Lee
- School of Civil and Environmental Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701, Republic of Korea
| | - Sae-Eun Oh
- Department of Environmental Engineering, Hanbat National University, San 16-1, Duckmyoung-dong, Yuseong-gu, Daejeon, Republic of Korea
| | - Mi-Sun Kim
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea; Division of Renewable Energy Engineering, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 305-350, Republic of Korea.
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Cho SK, Kim DH, Jeong IS, Shin HS, Oh SE. Application of low-strength ultrasonication to the continuous anaerobic digestion processes: UASBr and dry digester. Bioresour Technol 2013; 141:167-173. [PMID: 23582223 DOI: 10.1016/j.biortech.2013.03.116] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/16/2013] [Accepted: 03/16/2013] [Indexed: 06/02/2023]
Abstract
In this study, the positive effects of low-strength ultrasonication (LS-ultrasonication) on the anaerobic digestion (AD) performance were investigated by continuously operating an upflow anaerobic sludge blanket reactor (UASBr) and a dry digester. In the ultrasonicated UASBr system (1 s per min, 0.05 W/mL), ultrasonication enhanced the CH₄ production by 38% and 19% in an ambient and a mesophilic condition, respectively. In addition, a different sludge yield and a changed electron flow were observed after ultrasonication. In the ultrasonicated dry digestion system (2 s per 30 s, 0.0025 W/mL), a 40% increase in the production of CH₄ was observed after lowering the total solid content of the reactor from 12% to 10%, implying that a high solid content diminished the ultrasonic stimulation effect. Moreover, the ultrasonication strength itself appeared to be a more crucial factor than the ultrasonication density during the application of LS-ultrasonication in the AD system.
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Affiliation(s)
- Si-Kyung Cho
- Department of Civil and Environmental Engineering, KAIST, 373-1, Guseong-dong, Yuseong-gu, Daejeon, Republic of Korea
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Cho SK, Hwang YH, Kim DH, Jeong IS, Shin HS, Oh SE. Low strength ultrasonication positively affects the methanogenic granules toward higher AD performance. Part I: physico-chemical characteristics. Bioresour Technol 2013; 136:66-72. [PMID: 23563439 DOI: 10.1016/j.biortech.2013.02.111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 02/22/2013] [Accepted: 02/27/2013] [Indexed: 06/02/2023]
Abstract
To elucidate the correlation between enhanced biogas production and changed physico-chemical properties of methanogenic granules after low strength ultrasonication, in this study, the effects of low strength ultrasonication on the settling velocity, permeability, porosity, and fluid collection efficiency of the methanogenic granules were investigated. In addition, their morphological changes were visualized using a scanning electron microscopic technique. The experimental results indicate that low strength ultrasonication increased both the permeability (37%) and specific surface area (230%) of the granules through the generation of greater craters and cracks on the granular surface compared to the control granules. The penetration of nutrients and substrate into the granules was thereby enhanced, and more favorable conditions for achieving higher anaerobic performance were provided to the ultrasonicated granules. The microbial community shift caused by the changed physico-chemical properties of the methanogenic granules will be further analyzed in part II of this study.
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Affiliation(s)
- Si-Kyung Cho
- Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, Republic of Korea
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Cho SK, Im WT, Kim DH, Kim MH, Shin HS, Oh SE. Dry anaerobic digestion of food waste under mesophilic conditions: performance and methanogenic community analysis. Bioresour Technol 2013; 131:210-217. [PMID: 23347929 DOI: 10.1016/j.biortech.2012.12.100] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 12/11/2012] [Accepted: 12/13/2012] [Indexed: 06/01/2023]
Abstract
The performance of dry anaerobic digestion (AD) of food waste was investigated under mesophilic conditions and the methanogenic community was investigated using 454 pyrosequencing. Stable dry AD was achieved by hydraulic retention time (HRT) control without the addition of alkali agents. The average CH4 production rate, CH4 content, and volatile solid reduction rate were 2.51±0.17m(3)/m(3)/d, 66±2.1%, and 65.8±1.22%, respectively, at an HRT of 40d. The methanogenic community of the seed sludge experienced a significant reduction in genus diversity from 18 to 4 and a dominant methanogenic shift from hydrogenotrophic to acetoclastic groups after the acclimation under dry condition. Almost all sequences of the dry anaerobic digester were closely related with those of Methanosarcina thermophila with similarity of 96.4-99.1%. The experimental results would serve as useful information to understand the dry AD system.
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Affiliation(s)
- Si-Kyung Cho
- Department of Civil and Environmental Engineering, KAIST, 373-1, Guseong-Dong, Yuseong-gu, Daejeon, Republic of Korea
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Cho SK, Kim DH, Kim MH, Shin HS, Oh SE. Enhanced activity of methanogenic granules by low-strength ultrasonication. Bioresour Technol 2012; 120:84-88. [PMID: 22784957 DOI: 10.1016/j.biortech.2012.06.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 06/13/2012] [Accepted: 06/15/2012] [Indexed: 06/01/2023]
Abstract
In this study, low-strength ultrasonication was applied at various ultrasonication densities (UDs) (0-0.1 W/mL) and ultrasonication time (UT) (0-30 min) to methanogenic granules on the purpose of increasing their activity, and eventually, enhancing the performance of upflow anaerobic sludge blanket reactor (UASBr). Batch test results showed that 5 min of ultrasonication at 0.05 W/mL was found to be the optimal conditions, resulting in the increase of dehydrogenase activity and adenosine triphosphate content by 257%, and 374%, respectively, compared to the control. These increments were confirmed by specific methanogenic activity test. When ultrasonication (UD 0.05 W/mL, UT 5 min) was irradiated every 8h during the continuous operation of UASBr, it caused a gradual drop of methanogenic activity, complete loss after 20 days. At further operation, UT was decreased to 1s but irradiated every 1 min, which resulted in a 43% higher specific CH(4) production rate.
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Affiliation(s)
- Si-Kyung Cho
- Department of Civil and Environmental Engineering, KAIST, 373-1 Guseong-Dong, Yuseong-gu, Daejeon, Republic of Korea
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Kim DH, Oh SE. Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions. Waste Manag 2011; 31:1943-1948. [PMID: 21684733 DOI: 10.1016/j.wasman.2011.05.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 04/30/2011] [Accepted: 05/17/2011] [Indexed: 05/30/2023]
Abstract
With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO(2) emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) is attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH(4) production yield (MPY) and VS reduction achieved in this condition were 5.0m(3)/m(3)/d, 0.25 m(3) CH(4)/g COD(added), and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m(3)/m(3)/d, MPY of 0.26 m(3) CH(4)/g COD(added), and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to 60%, there was a significant performance drop, which was attributed to free ammonia inhibition. The performances in these two reactors were comparable to the ones achieved in the conventional wet digestion and thermophilic dry digestion processes.
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Affiliation(s)
- Dong-Hoon Kim
- Wastes Energy Research Center, Korea Institute of Energy Research, 102 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea
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Kim DH, Jeong E, Oh SE, Shin HS. Combined (alkaline+ultrasonic) pretreatment effect on sewage sludge disintegration. Water Res 2010; 44:3093-3100. [PMID: 20303565 DOI: 10.1016/j.watres.2010.02.032] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 01/23/2010] [Accepted: 02/19/2010] [Indexed: 05/29/2023]
Abstract
The individual effects of alkaline (pH 8-13) and ultrasonic (3750-45,000kJ/kg TS) pretreatments on the disintegration of sewage sludge were separately tested, and then the effect of combining these two methods at different intensity levels was investigated using response surface methodology (RSM). In the combined pretreatment, ultrasonic treatment was applied to the alkali-pretreated sludge. While the solubilization (SCOD/TCOD) increase was limited to 50% in individual pretreatments, it reached 70% in combined pretreatment, and the results clearly showed that preconditioning of sludge at high pH levels played a crucial role in enhancing the disintegration efficiency of the subsequent ultrasonic pretreatment. By applying regression analysis, the disintegration degree (DD) was fitted based on the actual value to a second order polynomial equation: Y=-172.44+29.82X(1)+5.30x10(-3)X(2)-7.53x10(-5)X(1)X(2)-1.10X(1)(2)-1.043x10(-7)X(2)(2), where X(1), X(2), and Y are pH, specific energy input (kJ/kg TS), and DD, respectively. In a 2D contour plot describing the tendency of DD with respect to pH and specific energy input, it was clear that DD increased as pH increased, but it seemed that DD decreased when the specific energy input exceeded about 20,000kJ/kg TS. This phenomenon tells us that there exists a certain point where additional energy input is ineffective in achieving further disintegration. A synergetic disintegration effect was also found in the combined pretreatment, with lower specific energy input in ultrasonic pretreatment yielding higher synergetic effect. Finally, in order to see the combined pretreatment effect in continuous operation, the sludge pretreated with low intensity alkaline (pH 9)/ultrasonic (7500kJ/kg TS) treatment was fed to a 3 L of anaerobic sequencing batch reactor after 70 days of control operation. CH(4) production yield significantly increased from 81.9+/-4.5mL CH(4)/g COD(added) to 127.3+/-5.0mL CH(4)/g COD(added) by pretreatment, and this enhanced performance was closely related to the solubilization increase of the sludge by pretreatment. However, enhanced anaerobic digestion resulted in 20% higher soluble N concentration in the reactor, which would be an additional burden in the subsequent nitrogen removal system.
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Affiliation(s)
- Dong-Hoon Kim
- Bioenergy Research Center, Korea Institute of Energy Research, Daejeon 305-343, Republic of Korea
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Oh SE, Kim JR, Joo JH, Logan BE. Effects of applied voltages and dissolved oxygen on sustained power generation by microbial fuel cells. Water Sci Technol 2009; 60:1311-7. [PMID: 19717919 DOI: 10.2166/wst.2009.444] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Oxygen intrusion into the anode chamber through proton exchange membrane can result in positive redox conditions in fed-batch, two chamber MFCs at the end of a cycle when the substrate is depleted. A slight increase in dissolved oxygen to 0.3 mg/L during MFC operation was not found to adversely affect power generation over subsequent cycles if sufficient substrate (acetate) was provided. Purging the anode chamber with air or pure oxygen for up to 10 days and 10 hrs also did not affect power generation, as power rapidly returned to previous levels when the chamber was sparged with nitrogen gas. When MFCs are connected in series, voltage reversal can occur resulting in a positive voltage applied to the anode biofilm. To investigate if this adversely affected the bacteria, voltages of 1, 2, 3, 4, and 9 V, were applied for 1 hr to the MFC before reconnecting it back to a fixed external load (1,000 Omega). A voltage of <2 V did not affect power generation. However, applying 3 V resulted in a 15 h lag phase before recovery, and 9 V produced a 60 h lag phase suggesting substantial damage to the bacteria that required re-growth of bacteria in the biofilm. These results indicate that charge reversal will be a more serious problem than oxygen intrusion into the anode chamber for sustained performance of MFCs.
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Affiliation(s)
- S E Oh
- Department of Biological Environment, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon, Kangwon-do 200-701, South Korea.
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Kim HW, Shin HS, Han SK, Oh SE. Response surface optimization of substrates for thermophilic anaerobic codigestion of sewage sludge and food waste. J Air Waste Manag Assoc 2007; 57:309-18. [PMID: 17385597 DOI: 10.1080/10473289.2007.10465334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
This study investigated the effects of food waste constituents on thermophilic (55 degrees C) anaerobic codigestion of sewage sludge and food waste by using statistical techniques based on biochemical methane potential tests. Various combinations of grain, vegetable, and meat as cosubstrate were tested, and then the data of methane potential (MP), methane production rate (MPR), and first-order kinetic constant of hydrolysis (kH) were collected for further analyses. Response surface methodology by the Box-Behnken design can verify the effects and their interactions of three variables on responses efficiently. MP was mainly affected by grain, whereas MPR and kH were affected by both vegetable and meat. Estimated polynomial regression models can properly explain the variability of experimental data with a high-adjusted R2 of 0.727, 0.836, and 0.915, respectively. By applying a series of optimization techniques, it was possible to find the proper criteria of cosubstrate. The optimal cosubstrate region was suggested based on overlay contours of overall mean responses. With the desirability contour plots, it was found that optimal conditions of cosubstrate for the maximum MPR (56.6 mL of CH4/g of chemical oxygen demand [COD]/day) were 0.71 g of COD/L of grain, 0.18 g of COD/L of vegetable, and 0.38 g of COD/L of meat by the simultaneous consideration of MP, MPR, and kH. Within the range of each factor examined, the corresponding optimal ratio of sewage sludge to cosubstrate was 71:29 as the COD basis. Elaborate discussions could yield practical operational strategies for the enhanced thermophilic anaerobic codigestion of sewage sludge and food waste.
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Affiliation(s)
- Hyun-Woo Kim
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea
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Oh SE, Bum MS, Yoo YB, Zubair A, Kim IS. Nitrate removal by simultaneous sulfur utilizing autotrophic and heterotrophic denitrification under different organics and alkalinity conditions: batch experiments. Water Sci Technol 2003; 47:237-244. [PMID: 12578200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The effect of various organic compounds were tested using lab-scale batch reactors. At sufficient alkalinity, the initial nitrate nitrogen concentration of 100 mg/L was completely reduced in all batch reactors. Sulfate production decreased by the addition of organics. The concentration range of organics used in this experiment did not inhibit autotrophic denitrification except for propionate. Propionate inhibited autotrophic denitrification a little, indicated by a lower sulfate production rate. Biomass in suspension increased with higher initial organic concentrations, showing higher DOC consumption. As the concentration of organics increased, alkalinity increased accordingly. Under the conditions of low alkalinity, in the case of a control reactor without organics, only about 30% of the initial nitrate was reduced. With half the theoretically required dosage of methanol, the denitrification rates increased slightly. When ethanol, acetate, and propionate were used, denitrification went to completion. When excess organics was added, however, sulfate production was significantly decreased. Interestingly, even when small amounts of organics were added, autotrophic denitrification was promoted as indicated by the sulfate production.
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Affiliation(s)
- S E Oh
- Dept. of Environmental Science & Engineering, Kwangju Institute of Science and Technology, Kwangju 500-712, Korea
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Kim IS, Oh SE, Bum MS, Lee JL, Lee ST. Monitoring the denitrification of wastewater containing high concentrations of nitrate with methanol in a sulfur-packed reactor. Appl Microbiol Biotechnol 2002; 59:91-6. [PMID: 12073138 DOI: 10.1007/s00253-002-0952-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2001] [Revised: 12/26/2001] [Accepted: 01/18/2002] [Indexed: 11/26/2022]
Abstract
Biological denitrification of high nitrate-containing wastewater was examined in a sulfur-packed column using a smaller amount of methanol than required stoichiometrically for heterotrophic denitrification. In the absence of methanol, the observed nitrate removal efficiency was only about 40%, and remained at 400 mg NO(3)(-)-N/l, which was due to an alkalinity deficiency of the pH buffer and of CO(2) as a carbon source. Complete denitrification was achieved by adding approximately 1.4 g methanol/g nitrate-nitrogen (NO(3)(-)-N) to a sulfur-packed reactor. As the methanol concentration increased, the overall nitrate removal efficiency increased. As influent methanol concentrations increased from 285 to 570, 855, and 1,140 mg/l, the value of Delta mg alkalinity as CaCO(3) consumed/Delta mg NO(3)(-)-N removed increased from -1.94 to -0.84, 0.24, and 0.96, and Delta mg SO(4)(2-) produced/Delta mg NO(3)(-)-N removed decreased from 4.42 to 3.57, 2.58, and 1.26, respectively. These results imply the co-occurrence of simultaneous autotrophic and heterotrophic denitrification. Sulfur-utilizing autotrophic denitrification in the presence of a small amount of methanol is very effective at decreasing both sulfate production and alkalinity consumption. Most of methanol added was removed completely in the effluent. A small amount of nitrite accumulated in the mixotrophic column, which was less than 20 mg NO(2)(-) -N/l, while under heterotrophic denitrification conditions, nitrite accumulated steadily and increased to 60 mg NO(2)(-) -N/l with increasing column height.
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Affiliation(s)
- I S Kim
- Department of Environmental Science and Engineering, Kwangju Institute of Science and Technology (K-JIST), 1 Oryong-dong, Puk-gu, Kwangju 500-712, Korea.
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Abstract
Sulfur-utilizing denitrification can be performed by denitrifying sulfur bacteria under autotrophic and heterotrophic conditions. To investigate the effect of organics (methanol and landfill leachate) on sulfur-utilizing denitrification, six laboratory-scale sulfur packed columns were operated under autotrophic, mixotrophic and heterotrophic conditions for approximately 1 year. The performance of the columns was monitored by measuring the pH, nitrate, nitrite, sulfate, sulfide, alkalinity dissolved organic carbon (DOC), and turbidity. These tests indicated that the mixotrophic column had a higher nitrate removal capacity than the autotrophic column. It was also found that under mixotrophic conditions, some portion of nitrate was removed heterotrophically and the remainder was denitrified by sulfur-utilizing autotrophic bacteria without inhibition by organics. In addition, sulfate production and alkalinity consumption were reduced under mixotrophic conditions. These results suggest that mixotrophic conditions that allow simultaneous reactions of autotrophic and heterotrophic denitrification provide significant advantages in terms of nitrate and DOC removal, sulfate production decrease, and alkalinity consumption over obligate autotrophic or heterotrophic denitrification.
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Affiliation(s)
- S E Oh
- Department of Environmental Science and Engineering, Kwangju Institute of Science and Technology (K-JIST), 1 Oryong-dong, Puk-gu, Kwangju 500-712, South Korea
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15
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Lee YW, Chung SY, Bogardi I, Dahab MF, Oh SE. Dose-response assessment by a fuzzy linear-regression method. Water Sci Technol 2001; 43:133-140. [PMID: 11380171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Regression analysis has been used to characterize the relationship between an exposure dose and the incidence of an adverse health effect such as cancer. However, the regression rarely describes the true relationship due to uncertainties in dose-response data and relationships. Therefore, a method is developed to perform dose-response assessments by a fuzzy linear regression which explicitly exhibit these uncertainties. This method is applied to define the relationship between a particular nitrate dose to humans and its corresponding cancer risk.
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Affiliation(s)
- Y W Lee
- Department of Environmental Engineering, Chonnam National University, 300 Yongbond-dong, Puk-ku, Kwangiu 500-757, Korea
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16
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Lee SC, Kang BG, Oh SE. Induction of ascorbate peroxidase by ethylene and hydrogen peroxide during growth of cultured soybean cells. Mol Cells 1999; 9:166-71. [PMID: 10340471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
In cultured soybean cells, a transient ethylene burst in the pre-stationary phase was followed by an induction of ascorbate peroxidase (AsPOX) in the stationary phase. Treatment of cells with the ethylene antagonist, silver thiosulfate (STS), resulted in the suppression of enzyme activity. Application of the ethylene releasing agent 2-chloroethylphosphonic acid (CEPA) in the medium led to an increased enzyme activity when treated in the pre-stationary phase. On the contrary, a remarkable inhibitory effect on enzyme activity was elicited by 1,3-dimethyl-2-thiourea (DMTU), trapping the hydrogen peroxide generated when treated in the stationary phase. Likewise, a steady level of AsPOX transcript was reduced by STS treatment. Furthermore, its effect appeared to be more rapid and prominent during the pre-stationary phase. It is suggested that the induction of AsPOX in cultured soybean cells during the stationary phase could result, at least in part, by the hydrogen peroxide generated as a result of preceding ethylene production.
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MESH Headings
- Amino Acid Sequence
- Ascorbate Peroxidases
- Base Sequence
- Cell Division/drug effects
- Cells, Cultured
- Cloning, Molecular
- Cytosol/enzymology
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Enzyme Induction/drug effects
- Ethylenes/metabolism
- Gene Expression Regulation, Plant/drug effects
- Hydrogen Peroxide/pharmacology
- Molecular Sequence Data
- Organophosphorus Compounds/pharmacology
- Peroxidases/genetics
- Peroxidases/metabolism
- Plant Growth Regulators/pharmacology
- RNA, Plant/drug effects
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Sequence Analysis, DNA
- Glycine max/cytology
- Glycine max/drug effects
- Glycine max/enzymology
- Thiosulfates/pharmacology
- Thiourea/analogs & derivatives
- Thiourea/pharmacology
- Transcription, Genetic/drug effects
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Affiliation(s)
- S C Lee
- Department of Biology, Konkuk University, Seoul, Korea
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17
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