• 환경위생공학
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• 제14권3호
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• pp.123-129
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• 1999

The utilization methods of algae biomass have been studied constantly in whole world. These are $\circled1$the wastewater treatment if waste stabilization pond and oxidation ditch etc. and $\circled2$the biosorption of heavy metals and recovery of strategic' precious metals and $\circled3$the single-celled protein production and the production of chemicals like coloring agent and $\circled4$the production of electric energy through methane gasification. The culture system also has been developed constantly in relation with such utilization method developments. In the result of experimental operation under continuous and cyclic irradiation of light, using high rate algae biomass culture pond(HRABCP), which had been made so as to be an association system with the various items which had been managed to have high efficiency for algae culture, the algae production of the 12 hours-irradiance pond was 41.48 Chlorophyll-a ${\mu}g/L$ only in spite of having the more chance of $CO_2$ synthesis to algae cell than the 24 hours-irradiance pond. This means that the energy supply required for dark-reaction of photosynthesis is very important like this. The difference of algae production between continuous and cyclc irradiation explains that the dark-reaction of photosynthesis acts on algae production as the biggest primary factor. The continuous irradiance on HRABCP made the good algae-production($1403.97{\;}{\mu}g$ Chlorophyll-a/mg) and the good oxygen-production(5.8 mg $O_2/L$) and the good solid-liquid seperation. especially, DO concentration through the oxygen-production was enough to fishes' survival.

• 상하수도학회지
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• 제18권4호
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• pp.515-521
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• 2004

Anaerobic digestion has many advantages over the more conventional aerobic treatment processes such as low levels of excess sludge production, low space (area) requirements, and the production of valuable biogas. The purpose of this study was to evaluate the effect of organic loading rate of anaerobic digestion on thermophilic($55^{\circ}C$) and mesophilic($35^{\circ}C$) conditions. Fluorescent in situ hybridization (FISH) method was also used to study the microbial community in the reactors. The stabilizing time in mesophilic anaerobic reactors was shorter as approximately 20 days than 40 days in the thermophilic anaerobic reactors. The amount of methane production rate in anaerobic reactors was independent of the concentrations of supplied substrates and the amount of methanogens. When the microbial diversity in the mesophilic and thermophilic reactors, which had been treated with acetate-based artificial wastewater, were compared, it was found that methanogenesis was carried out by microbial consortia consisting of bacteria and archaea such as methanogens. To investigate the activity of bacterial and archaeal populations in all anaerobic reactors, the amount of acetate was measured. Archaea were predominant in all reactors. Interestingly, Methanothrix-like methanogens appeared in mesophilic anaerobic reactors with high feed substrate concentrations, whereas it was not observed in thermophilic anaerobic reactors.

• 농업생명과학연구
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• 제50권2호
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• pp.95-105
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• 2016

본 시험은 질산염함유 식물 추출물을 이용하여 in vitro 반추위 발효성상 및 반추위 메탄 발생에 미치는 영향을 알아보기 위해 수행되었다. 공시재료는 감자, 당근, 배추, 상추 및 시금치 추출물을 사용하였으며, 발효 기질은 2mm로 분쇄된 timothy 0.3g을 사용하였다. In vitro 실험은 조사료(timothy) 및 배합사료를 6:4의 비율로 급여한 반추위 cannnula가 시술된 한우 암소에서 채취하였다. 반추위액과 McDougall's buffer를 1:2의 비율로 혼합한 발효액을 0.3g timothy와 식물 추출물이 담긴 50mL serum bottle에 혐기상태로 20mL 분주한 뒤, 39℃에서 9, 12, 24, 48시간 동안 발효하였다. pH는 발효 시간이 증가함에 따라 점점 감소하며, 6.31~6.96으로 정상범위였다. 건물 소화율은 9시간 배추 추출물구에서 유의적으로 낮았고, 암모니아 농도는 감자, 배추, 상추 추출물구에서 대조구에 비해 첨가구에서 유의적으로(p<0.05) 낮았으며, 반추위 미생물 성장량은 발효 24시간대의 당근 추출물구에서 높았다(p<0.05). Acetate와 propionate 농도는 대조구에 비해 첨가구에서 유의적으로 낮았으며(p<0.05) butyrate 농도는 첨가구간에 발효시간별로 각각 다른 양상을 보였다. 총 가스 발생량은 발효 12시간 및 24시간대에서 배추, 상추, 시금치 추출물구에서 유의적으로(p<0.05) 낮았으며, 메탄 발생량은 감자, 배추, 시금치 추출물구가 대조구에 비해 유의적으로(p<0.05) 낮았고, 이산화탄소 발생량 또한 첨가구에 비해 대조구에서 유의적으로(p<0.05) 낮았다. 결과적으로 본 시험에 사용된 5종의 질산염 함유 식물 추출물은 반추위 발효에 악영향을 미치지 않으면서 메탄저감 효과를 나타내었다. 특히 배추 추출물은 반추위내 메탄발생을 저감시킬 수 있는 식물추출물로서 가능성이 높은 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.737-743
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• 1999

A conventional thermophilic anaerobic digester was converted into a thermophilic high-rate hybrid anaerobic reactor (THAR) for treating distillery wastewater. The THAR has been operating successfully since May 1995 at a loading rate of 5.45 to $11.52{\;}kg/\textrm{m}^3/d$ (maximum of 15.02). The THAR has demonstrated a soluble Chemical Oxygen Demand (sCOD) removal efficiency of 85 to 91% and a total COD (tCOD) removal efficiency of as much as 72 to 84%. Product gas had a methane content of 59 to 68%. The tCOD removal rates were 4.31 to 5.43, 6.26 to 6.89, and 9.03 to $9.78kg{\;}tCOD/\textrm{m}^3/d$ for tapioca, com, and naked-barley wastewater, respectively. The sCOD removal rates ranged from 3.75 to 4.79,3.28 to 4.89, and 5.57 to 6.21kg $sCOD/\textrm{m}^3/d$ for tapioca, com, and naked-barley wastewater, respectively. There were unknown substances in a naked-barley distillery wastewater that were identified as being toxic for microorganisms. However, the THAR treated naked-barley wastewater continuously for 26 days, operating at an average tCOD loading of $11.08{\;}kg/\textrm{m}^3/d$without any signs of deterioration in either COD removal efficiency or gas production rate. During this period, the average removal efficiencies of tCOD and sCOD were 84% and 91%, respectively, and the gas production rate averaged 6.61 to $7.57{\;}\textrm{m}^3/\textrm{m}^3$ reactor/d which produced 0.57 to $0.69{\;}\textrm{m}^3{\;}biogas/kg{\;}tCOD_{rem}$. From tapioca and com wastewater, the reactor showed an average gas production rate of 3.18 to 3.46 and 4.91 to $5.22{\;}\textrm{m}^3/\textrm{m}^3$ reactor/d which produced 0.53 to 0.69 and 0.62 to $0.71{\;}\textrm{m}^3/kg{\;}tCOD_{rem}$, respectively.

• 대한환경공학회지
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• 제31권5호
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• pp.341-345
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• 2009

음식물쓰레기와 종이류로 구성된 유기성고형폐기물(고형물 함량 30% TS)을 대상으로 중온 건식혐기성소화를 시도하였고, 연속 운전 중 수리학적 체류 시간(HRT)을 150일, 100일, 60일, 40일로 감소시켰다. 기질의 고형물 농도를 30% TS (Total Solids)로 고정하였기 때문에 각각의 HRT에 해당하는 고형물 부하는 2.0, 3.0, 5.0, 7.5 kg TS/$m^3$/d였다. HRT를 줄임에 따라 단위용적 당 바이오가스 생산 속도는 증가하였고, HRT 40일에서 3.49${\pm}$0.31 $m^3/m^3/d$로 가장 높은 성능을 보였다. 이 때, 76%의 휘발성 고형물(VS) 분해율이 유지되었고, 0.25 $m^3$/kg $TS_{added}$의 메탄 생산 전환율을 보였으며, 이는 기질의 67.4%에 해당하는 에너지가 메탄 가스로 전환된 것을 의미한다. HRT 100일에서 0.52 $m^3$/kg $TS_{added}$로 가장 높은 바이오가스 전환율을 보였지만, 모든 HRT에서 0.45${\sim}$0.52 $m^3$/kg $TS_{added}$로 큰 차이가 나지 않았다. 고형물 함량이 높은 기질의 원활한 주입을 위해 소화조 발효액의 일부를 기질 투입구로 반송하여 기질과 혼합 후 주입하였다. 주입하고자 하는 기질의 5배에 해당하는 양의 소화조 발효액을 반송하여 혼합하였을 때, 가장 효과적인 기질 주입이 이루어졌다. 중온 건식 조건에서 서식하는 메탄 소화균의 활성도를 측정한 결과, 아세트산, 뷰틸산, 프로피온산을 이용할 경우 각각 2.66, 1.94, 1.20 mL $CH_4/g$ VS/d였다.

• 에너지공학
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• 제23권1호
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• pp.33-39
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• 2014

본 연구에서는 하수슬러지의 소화가스 생산 효율향상을 위해 전기분해 처리방법을 수행하고 이를 소화가스 생산과 탈질실험 효과를 확인하였다. 전기분해 처리시간, 전류밀도가 증가함에 따라 가용화율은 증가하였으며 전극간격 4 mm에서 전류밀도 10 mA/cm2로 60분 처리 시 가용화율은 9.02%를 보였다. 이를 이용하여 BMP실험을 진행한 결과 0.49 L CH4/g VS의 메탄생산량을 보이며 대조군대비 88.4% 증가함을 보였다. 같은 조건으로 처리된 하수슬러지를 이용하여 탈질실험을 진행한 결과 $19.2mg\;NO_3{^{-}}N/g\;MLVSS{\cdot}hr$의 탈질율을 보였으며 이를 통해 전기분해 처리된 하수슬러지는 생분해성이 증대됨에 따라 혐기성소화와 탈질공정에도 적용이 가능한 것으로 확인되었다.

• 한국물환경학회지
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• 제38권2호
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• pp.95-102
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• 2022

Studies for improving the efficiency of the traditional anaerobic digestion process are being actively conducted. To improve anaerobic digestion efficiency, this study tried to derive the optimal pretreatment conditions and mixing conditions by integrating the heat solubilization pretreatment of sewage sludge, livestock manure, and food waste. The soluble chemical oxygen demand (SCOD) increase rate of sewage sludge before and after heat solubilization pretreatment showed an increased rate of 224.7% compared to the control group at 170℃ and 25 min and showed the most stable increase rate. As a result of the biomethane potential test of sewage sludge before and after heat solubilization pretreatment, the total chemical oxygen demand (TCOD) and SCOD removal rates increased as the heat solubilization temperature increased, but did not increase further at temperatures above 170℃. In the case of methane generation, there was no significant change in the cumulative methane generation from 0.134 to 0.203 Sm³-CH₄/kg-COD at 170℃ for 15 min. As a result of the integrated digestion of organic waste, the experimental condition in which 25% of the sewage sludge, 50% of the food waste, and 25% of the livestock manure were mixed showed the highest methane production of 0.3015 m³-CH₄/kg-COD, confirming that it was the optimal mixing ratio condition. In addition, under experimental conditions mixed with all three substrates, M4 conditions mixed with 25% sewage sludge, 50% food waste, and 25% livestock manure showed the highest methane generation at 0.2692 Sm³-CH₄/kg-COD.

• 대한환경공학회지
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• 제31권11호
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• pp.997-1006
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• 2009

본 연구에서는 음폐수를 대상으로 5 톤/일 처리규모의 막결합형 2상 혐기성 소화(TPADUF) 플랜트를 운영하며 유기물 제거효율 및 메탄 발생량을 파악하고, 소화가스를 이용한 발전 가능성 및 분리막 적정 운영방안을 검토하였다. 고온 산발효조, 중온 메탄조 및 UF 막으로 구성된 처리 시스템에서 평균 TCOD가 150 g/L인 음폐수를 유기물 부하 11.1 g COD/L/d까지 증가시키며 처리한 결과 최종 유출수의 TCOD는 6 g/L 이하이었으며, TCOD 및 SCOD 제거효율은 모두 95% 이상이었다. 소화 가스의 메탄 구성비는 65%이었으며, 회수된 메탄량은 시스템에서 일부 가스가 누출되었음에도 39 $m^3/m^3$ 음폐수 주입량, 260 $m^3$/톤 COD유입량, 또는 270 $m^3$/톤 COD제거량 이었다. 소모된 가스량 당 발전량은 0.96 kWh/$m^3$ 가스, 또는 1.49 kWh/$m^3$ 메탄으로 다소 낮았으나 이는 소용량 발전기(15 kW급)의 저효율에 기인한 것이다. 분리막은 평균 flux 10 L/$m^2$/hr에서 운전하였으며, 운전 중 flux가 감소하였을 때는 물 또는 화학적(NaOCl)세정을 실시하여 회복시킬 수 있었다. TPADUF 플랜트에서는 메탄조 내액 또는 분리막 농축액을 산발효조로 반송함으로써 산발효조의 pH를 별도의 약품 주입 없이 적정 수준을 유지할 수 있었으며, 산발효조에서 부분적인 메탄생성을 통해 메탄조의 유기물 부하를 낮추는 효과도 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.465-469
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• 2006

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and tested for hydrogen production via anaerobic fermentation of sucrose. Each reactor consisted of a column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed with changing flow rate into the capped reactor, hydraulic retention time and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% for all conditions tested. Hydrogen production rates increased up to $10.5 L{\cdot};h^{-1}{\cdot}L^{-1}$ of reactor when influent sucrose concentrations and recycle rates were varied. Hydrophobic media provided higher value of hydrogen production rate than hydrophilic media at the same operation conditions. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate and butyrate. The reactor filled with hydrophilic media became clogged with biomass and bio gas, requiring manual cleaning of the system, while no clogging occurred in the reactor with hydrophobic media. In order to make long-term operation of the reactor filled with hydrophilic media feasible, biofilm accumulation inside the media in the reactor with hydrophilic media and biogas produced from the reactor will need to be controlled through some process such as periodical backwashing or gas-purging. These tests using trickling bed biofilter with hydrophobic media demonstrate the feasibility of the process to produce hydrogen gas in a trickle-bed type of reactor. A likely application of this reactor technology could be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.

• 상하수도학회지
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• 제8권1호
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• pp.27-33
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• 1994

With the rapid industrialization, an ever-increasing quantity and kind of new organic compounds pose environmental problems due to their toxicity and physiological effect. However, research on the biodegradation of these compounds under anaerobic condition is very limited inspite of its efficiency and economical advantage. In this research, the pH effect on the ring cleavage of phenol under anaerobic condition was investigated, and the theory of phase separation was applied to the degradation of phenol for investigating the role of acidogenic bacteria. Results, obtained from biochemical methane potential(BMP) assay for 15.5 days of incubation, showed that acidic condition was more desirable for phenol degradation than alkaline condition. By both unacclimated methanogenic granular sludge and two mixed cultures, phenol was completely removed within six weeks of incubation with a gas conversion rate of over 86% of theoretical one. However, phenol was not degraded by unacclimated acidogenic culture, and thus it is considered as a syntrophic substrate. In case of phase separated biochemical methane potential(PSBMP) assay, in which acidogenic and methanogenic culture were seeded separately and consecutively, those that had been subjected to normal acidogens for 3 to 4 weeks showed higher gas production than those seeded with sterile or frozen culture.