• 대한산업공학회지
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• 제22권1호
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• pp.155-164
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• 1996

Biomass to methane via anaerobic digestion conversion is a good supply method of substitutable energy resources. The economic viability of this technology is contingent upon managing the production facilities in a cost effective manner. The problem is to determine the batch production sequence as well as the batch residence times in the digester so as to maximize total gas production over a given planning horizon. The problem is difficult to solve since the batch sequencing decisions and the batch residence time decisions cannot be isolated. This paper developes a heuristic algorithm which is based on a dynamic programming procedure for the multiple feedstock sequencing and scheduling biogas production systems and demonstrates to yield good results.

• 한국관개배수논문집
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• 제18권2호
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• pp.25-32
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• 2011

The 21 livestock farms considering future installation of biogas systems were studied. These farms were examined how to raise the livestock, to treat manure, to operate facility with respect to manure characteristics. The 15 farms out of 21 farms have applied to the marine dumping and consignment treatment for treating manure and even farms which have equipped liquid fertilizing system have less capacity facility than legal standards. Characteristics of manure were affected by the scale of swine barn, clean water usage, frequency of cleaning, cleaning method, feces-urine separating method, etc. Retention time in storage (over 20 days) has resulted in lower concentration of organic matter which could reduce biogas production. This indicates that systematic barn management system is required. Inhibition tests showed that disinfectant and citric acid did not affected digestion rates at 10 times higher concentration than recommendation. However hypochlorous acid is likely to affect the anaerobic microbial activity.

• 한국환경농학회지
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• 제26권1호
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• pp.1-6
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• 2007

본 연구에서는 바이오가스의 연소엔진을 이용한 에너지 전환시에 발생되는 $NO_x$와 CO의 배출특성을 분석하고 나아가 배출계수를 산정하고자 하였다. 바이오가스의 주성분인 메탄을 70%로 한 합성가스를 이용하여 실험한 결과 연소엔진의 표준상태에서 $NO_x$와 CO가 각각 4 ppm과 100 ppm의 배출농도를 나타내었고, 이는 1.29g/MMBtu와 30.86 g/MMBtu의 배출계수 값을 산정할 수 있었다. 바이오가스의 주성분인 메탄을 60%로 한 약간의 과잉공기의 상태에서는 $NO_x$와 CO가 각각 2 ppm과 200 ppm의 배출농도를 나타내었고, 이는 정격 조건에 비해 투입열량이 적어져 연소온도의 저하로 인하여 열적 반응에 의해 생성되는 $NO_x$는 줄고, CO는 증가함을 알 수 있었다. 미국 EPA의 배출계수를 비교하기 위하여 투입된 연료의 열량을 기준으로 비교해 볼 때 본 연구의 결과가 $NO_x$의 경우 근사한 값을 보여 주었고, 이는 국내 바이오 가스 연소시의 오염배출계수로 잘 적용 가능함을 보여 주었다. 본 연구에서 사용한 가스엔진이 오염배출 측면에서 대기 환경보전법상의 배출 허용기준 내에서 가동됨을 알 수 있었고, 가동조건에 따라 연소온도를 증가시킴으로서 CO의 발생을 저감시킬 수 있으리라 사료된다.

• 대한토목학회논문집
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• 제35권2호
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• pp.353-359
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• 2015

본 연구는 실제 아파트 단지의 재생이 필요한 환경 인프라를 경제적이고 효율적인 녹색 인프라 기술로 재생하기 위한 계획을 수립하였으며, 단지내 물과 폐기물의 자원 순환 및 재이용을 위해 단지형 도시 중수 생산 기술과 단지형 유기성 폐기물 에너지화 기술, 무막힘 탄성포장 우수 재이용 기술, 도시농장 기술을 현장에 적용한 결과를 보여주고 있다. 도심 중수 생산 기술은 하수, 우수, 지하수를 대상으로 중수를 생산하여 단지내 공공용수로 이용하기 위한 기반 기술이며, 무막힘 탄성포장 우수배수구 기술은 단지 내에서 우수의 재이용율 극대화시키기 위한 기반 기술이다. 유기성 폐기물 에너지화 기술은 단지에서 발생하는 음식폐기물 및 분뇨 등의 유기성 폐기물을 처리하는 과정에서 바이오가스와 비료를 만들어 에너지원으로 활용할 수 있으며, 도시농장은 재생용수, 재생에너지, 재생비료를 활용하여 주거민들의 건강 및 여가공간으로 활용할 수 있는 기반기술이다. 이를 통해 단지 내에서 자원 순환 및 재이용이 가능한 하나의 에코시스템을 구축하였으며, 재생 후 녹색지표결과에서 에너지 부문은 4.23, 물부문은 0.32, 폐기물 부문은 0, 토지이용 부문은 0, 환경부문은 2.12가 상승하는 결과를 가져올 수 있었다.

• Environmental Engineering Research
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• 제25권1호
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• pp.80-87
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• 2020

Landfill waste decomposition generates a dark effluent named, leachate which is characterized by high organic matter content. To minimize these polluting effects, it becomes necessary to develop an effective landfill leachate treatment process. The objective of this study was to evaluate the performance of an innovative approach based on air stripping, anaerobic digestion (AD) and aerobic activated sludge treatment. A reduction of 80% of ammonia and an increase of carbon to nitrogen ratio to 25 were obtained, which is a suitable ratio for AD. This latter AD was performed in fixed bed reactor with progressive loading rate that reached 2 and 3.2 g COD/L/d for the raw and diluted leachate (1:2), respectively. The anaerobic treatment led to significant removal of chemical oxygen demand (COD) and biogas production, especially for the diluted leachate. The COD removal was of 78% for the raw leachate and a biogas production of 4 L/d with 70% methane content. The use of the diluted leachate led to 81% of COD removal and 7 L/d biogas with 75% methane content. It allowed a removal of 77% COD and more than 97% of the organic compounds present in the initial leachate sample.

• 한국토양비료학회지
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• 제49권3호
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• pp.227-234
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• 2016

The influence of mixing on biogas production and organic material removal performance of solid state anaerobic digestion of dairy manure and sawdust bedding mixtures was evaluated using 22 L volume lab-scale digesters. After 45 days of anaerobic digestion at $37^{\circ}C$, cumulative methane yield of unmixed test unit ($73.1N{\cdot}mL/g-VS$) was almost 1.3 times of that of mixed one ($56.3N{\cdot}mL/g-VS$). The biodegradable volatile solids removal rate of unmixed test unit was 67%, which was almost 28% greater than mixed one. Our results reveal that unmixed condition is better than mixed one in terms of biogas production and organic material reduction.

• 한국환경보건학회지
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• 제19권3호
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• pp.17-21
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• 1993

Characteristics of a downflow anaerobic packed bed reactor with raschig ring ceramics as a packing were measured and discussed for the basic evaluation of the process. A synthesized glucose substrate wastewater were used as a feed and process characteristics such as pH, biogas production, composition of produced gas, COD removal and VSS were measured with the hydraulic retention time (HRT) changing from 0.25 to 2 days. As a result, this type of reactor was applicable in continuous operation within the given HRT range and the transient period approaching the steady state was about 20 days. The content of methane in produced gas increase with HRT was always high above 50% enough to use as energy source. The COD removal efficiency increased gradually as HRT increased. The axial profile of VSS concentration in the reactor usually showed the maximum at the lower region and the minimum at the middle. The VSS concentration at the upper region and the exit appeared similarly. However, at 0.25 day of HRT, the VSS concentration of effluent became higher than that of the upper region. Therefore the optimum HRT of this reactor occurred about 0.5 day, at which the production of methane began to be just stabilized and loss of VSS and COD removal were resonable.

• 한국수소및신에너지학회논문집
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• 제23권3호
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• pp.236-242
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• 2012

This study has been carried out the experiment for the possibility of biogas reforming using waste heat. The source of this waste heat is the exhaust gas from a small-sized gas engine generator. For recovering the waste heat, Two-stage heat exchanger is manufactured. The two-stage heat exchanger is composed of a heat exchanger for the exhaust gas and a heat exchanger for the water. This two-stage heat exchanger is used for reforming the biogas by means of on-site hydrogen production at the small-sized gas engine generator. The two-stage heat exchanger is coupled with the biogas reformer which is a kind of catalytic reformer. To confirm a heat recovery efficiency of the two-stage heat exchanger, temperature differences of inlet and outlet locations are measured. Also, the variations of syngas concentrations with various biogas flow rates are investigated. As a result using manufactured two-stage heat exchanger, the biogas can be reformed from waste heat recovery. This experiment suggests that the exhaust gas heat exchanger is available for reforming the biogas.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.258-265
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• 2023

축산용 항생제는 투여된 양의 일부만이 체내에서 사용되며 나머지는 모화합물 형태나 대사체로서 분뇨를 통하여 배출된다. 이러한 분뇨는 자원화 시설로부터 퇴액비로 생산되어 농경지에 살포됨으로써 농업환경에 유입되어 2차 오염 등을 초래하고 있다. 본 연구는 국내 가축분뇨 자원화 시설의 액비 생산단계별로 6종 축산용 항생제의 잔류 농도를 비교하고 액비 성분 질소 함량과의 상관성을 평가하기 위해 수행되었다. Buffer 및 SPE를 사용한 전처리 방법은 ppb 수준에서 63.4-106.7%의 회수율을 나타냈으며, 정량한계의 범위는 0.009-0.037 ㎍/L이었다. 공동자원화 시설 생산 액비의 생산단계별 잔류 항생제 농도와 규격함량 N 성분 함량과의 상관성 평가를 분석한 결과 액비화 과정 중 부숙 기간이 경과함에 따라 N 성분 및 항생제 잔류 농도가 감소하는 경향을 보여 주었다. 액비 원료, 중기 및 제품 중 SMZ의 평균 잔류 항생제는 40.85, 26.17, 3.54 ㎍/L이었으며 CTC의 경우 2.32에서 1.25 ㎍/L 수준으로 감소하였다. 다른 4종 항생제 역시 생산단계별로 잔류 농도가 감소하는 경향을 보여주었으며 액비 규격성분 N은 생산단계별 함량이 0.21에서 0.096%로 감소하였다. 액비 생산단계별 잔류 항생제 농도와 규격 성분 N 함량과의 상관성 평가는 항생제 저감화 지표 설정의 기초자료로 활용 가능할 것으로 판단된다.

• Environmental Engineering Research
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• 제25권1호
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• pp.114-122
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• 2020

This study was aimed at using the Central Composite Design (CCD) and Box-Behnken Design (BBD) to compare the efficiency and to elucidate the main interacting parameters in the upflow anaerobic sludge blanket (UASB) reactor, namely: Organic Loading Rate (OLR), Hydraulic Retention Times (HRT) and pH at a constant temperature of 35℃. Optimum HRT (15 h), OLR (3.5 kg.m^-3.d^-1) and pH (7) resulted in biogas production of 5,800 mL/d and COD removal of 80.8%. BBD produced a higher desirability efficiency of 94% as compared to the CCD which was 92%. The regression quadratic models developed with high R² values of 0.961 and 0.978 for both CCD and BBD, respectively, demonstrated that the interaction models could be used to pilot the design space. BBD model developed was more reliable with a higher prediction of biogas production (5,955.4 ± 225.3 mL/d) and COD removal (81.5 ± 1.014%), much close to the experimental results at a 95% confidence level. CCD model predictions was greater in terms of COD removal (82.6 ± 1.06% > 80.8%) and biogas production (4,636.31 mL/d ± 439.81 < 5,800 mL/d) which was less than the experimental results. Therefore, RSM can be adapted for optimizing various wastewater treatment processes.