• Membrane and Water Treatment
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• 제10권3호
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• pp.213-221
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• 2019

Anaerobic digestion (AD) has been widely used to valorize food waste (FW) because of its ability to convert organic carbon into $CH_4$ and $CO_2$. Korean FW has a high content of fruits and vegetables, and efficient hydrolysis of less biodegradable fibers is critical for its complete stabilization by AD. This study examined the digestates from different anaerobic digesters, namely Rs, Rr, and Rm, as the inocula for the AD of vegetable waste (VW) and cellulose (CL): Rs inoculated with anaerobic sludge from an AD plant, Rr inoculated with rumen fluid, and Rm inoculated with anaerobic sludge and augmented with rumen fluid. A total of six conditions ($3\;inocula{\times}2\;substrates$) were tested in serial subcultures. Biogas yield was higher in the runs inoculated with Rm than in the other runs for both VW (up to 1.10 L/g VS added) and CL (up to 1.05 L/g VS added), and so was biogas production rate. The inocula had different microbial community structures, and both substrate type and inoculum source had a significant effect on the formation and development of microbial community structures in the subcultures. The overall results suggest that the bioaugmentation with rumen microbial consortium has good potential to enhance the anaerobic biodegradability of VW, and thereby can help more efficiently digest high fiber-content Korean FW.

• 웰빙융합연구
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• 제6권2호
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• pp.33-37
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• 2023

Purpose: Since 2013, marine dumping of wastewater has been banned, and research on eco-friendly and efficient land treatment has emerged. This study compared and tested changes in biogas production and anaerobic process efficiency depending on whether or not enzyme pretreatment was performed during anaerobic digestion from single-phase and two-phase to medium-temperature. Research design, data and methodology: The total sugar, direct sugar, pH, and acidity before and after fermentation were analyzed by G/C by anaerobic fermentation of the liquor wastewater, food wastewater 1, and food wastewater 2 at 30℃ for 67 hours, and the amount of methane gas generated was analyzed by balloon volume. Results: It was found that stable organic acid concentration and pH were found in the enzyme-treated food wastewater 2, and the amount of methane gas generated was also increased. Conclusions: When anaerobic digestion of the liquor wastewater and the food wastewater together, the performance of enzyme pretreatment resulted in increased digestive efficiency. It will be the basic data that can contribute to carbon neutrality and greenhouse gas reduction by increasing the production of biogas.

• Environmental Engineering Research
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• 제24권4호
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• pp.662-669
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• 2019

Anaerobic digestion is a popular sewage sludge (Ss) treatment method as it provides significant pollution control and energy recovery. However, the low C/N ratio and poor biodegradability of Ss necessitate pretreatment methods that improve solubilization under anaerobic conditions in addition to anaerobic co-digestion with other substrates to improve the process efficiency. In this study, three pretreatment methods, namely microwave irradiation, ultrasonication, and heat treatment, were investigated, and the corresponding improvement in methane production was assessed. Additionally, the simplex centroid design method was utilized to determine the optimum mixture ratio of food waste (Fw), livestock manure (Lm), and Ss for maximum methane yield. Microwave irradiation at 700 W for 6 min yielded the highest biodegradability (62.0%), solubilization efficiency (59.7%), and methane production (329 mL/g VS). The optimum mixture ratio following pretreatment was 61.3% pretreated Ss, 28.6% Fw, and 10.1% Lm. The optimum mixture ratio without pretreatment was 33.6% un-pretreated Ss, 46.0% Fw, and 20.4% Lm. These results indicate that the choice of pretreatment method plays an important role in efficient anaerobic digestion and can be applied in operational plants to enhance methane production. Co-digestion of Ss with Fw and Lm was also beneficial.

• 대한환경공학회지
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• 제32권9호
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• pp.894-899
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• 2010

슬러지 감량 효율을 높이기 위해 오존전처리와 고 액분리조를 이용한 이상 혐기성 소화 공정 통해 다음과 같은 결과를 얻었다. 오존전처리를 통한 슬러지의 고형물 농도는 평균 TSS $8.3{\pm}2.0%$, VSS $9.2{\pm}2.8%$의 감소율을 나타내었다. 유기물 농도인 TCOD는 평균 $5.1{\pm}2.4%$ 감소하는 반면 SCOD는 평균 $72.0{\pm}6.5%$ 증가하였는데, 이는 오존으로 인해 세포내의 고분자 유기물이 용출되어 가용화되었기 때문이다. 이상 혐기성 소화 공정의 반응조별 소화가 진행됨에 따라 평균 TSS $21.5{\pm}3.4%$, VSS $20.2{\pm}8.4%$, TCOD $32.1{\pm}7.9%$, SCOD $22.1{\pm}7.2%$의 농도가 감소하였다. 최대 메탄생성량은 177.6 mL $CH_4/g$ TSS, 210.8 mL $CH_4/g$ VSS, 127.0 mL $CH_4/g$ TCOD, 1452.0 mL $CH_4/g$ SCOD이었다. 이상 혐기성 소화와 MLE 하수처리 공정의 연계처리 후 고형물 물질수지 결과 TSS 93.8%, VSS 92.0%의 감소율을 보였다. 이상 혐기성 소화 공정은 슬러지 처리 문제 해결과 신 재생에너지인 바이오가스 회수의 가능성을 보여줌으로서 향후 슬러지 감량에 해결책이 될 수 있을 것으로 사료된다.

• 한국축산시설환경학회지
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• 제11권2호
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• pp.97-102
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• 2005

Anaerobic decomposition is one of the most common processes in nature and has been extensively used in waste and wastewater treatment for several centuries. New applications and system modifications continue to be adapted making the process either more effective, less expensive, or suited to the particular waste in question and the operation to which it is to be applied. Animal manure is a highly biodegradable organic material and will naturally undergo anaerobic fermentation, resulting in release of noxious odors, such as in manure storage pits. Depending on the presence or absence of oxygen in the manure, biological treatment process may be either aerobic or anaerobic. Under anaerobic conditions, bacteria carry on fermentative metabolisms to break down the complex organic substances into simpler organic acids and then convert them to ultimately formed methane and carbon dioxide. Anaerobic biological systems for animal manure treatment include anaerobic lagoons and anaerobic digesters. Methane and carbon dioxide are the principal end products of controlled anaerobic digestion. These two gases are collectively called biogas. The biogas contains $60\~70\%$ methane and can be used directly as a fuel for heating or electrical power generation. Trace amounts of ammonia and hydrogen sulfide ($100\~300\;ppm$) are always present in the biogas stream. Anaerobic lagoons have found widespread application in the treatment of animal manure because of their low initial costs, ease of operation and convenience of loading by gravity flow from the animal buildings. The main disadvantage is the release of odors from the open surfaces of the lagoons, especially during the spring warm-up or if the lagoons are overloaded. However, if the lagoons are covered and gases are collected, the odor problems can be solved and the methane collected can be used as a fuel. Anaerobic digesters are air-tight, enclosed vessels and are used to digest manure in a well-controlled environment, thus resulting in higher digestion rates and smaller space requirements than anaerobic lagoons. Anaerobic digesters are usually heated and mixed to maximize treatment efficiency and biogas production. The objective of this work was to review a current anaerobic biological treatment of animal manure for effective new technologies in the future.

• 공업화학
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• 제23권2호
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• pp.228-231
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• 2012

본 연구에서는 혐기성 생물 반응조에서 35일 동안 배양된 하수슬러지와 판지슬러지를 혼합한 후, 초음파 파쇄기를 이용한 고농도 유기성 폐기물의 회분식 혐기 소화 공정에서 메탄 생산 특성이 고찰되었다. 초음파 파쇄기의 진폭이 높아질수록 Soluble Chemical Oxygen Demand (SCOD)가 증가함으로써 판지슬러지의 효과적 가용화가 이루어졌다. 또한, 메탄 생산성 향상을 위한 초음파 파쇄기의 최적 진폭이 $142.5\;{\mu}m$임을 구하였으며, 혐기소화 기간이 길러질수록 메탄 생산량은 증가하였다. 그리고, 바이오매스 변화(6000, 9000, 12000 mg/L)에 의한 혐기성 소화처리가 이루어졌을 때, 미생물 농도가 높아질수록 메탄 생산량이 모두 증가함을 알 수 있었다. 이러한 실험 결과들은 판지슬러지와 하수슬러지가 혼합된 고농도 유기성 폐기물의 혐기성 소화 공정에 의한 메탄 생산성을 향상시키는 자료로 활용될 수 있을 것이다.

• 한국환경과학회지
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• 제27권9호
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• pp.737-742
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• 2018

Livestock manure treatments have become a more serious problem because massive environmental pollutions such as green and red tides caused by non-point pollution sources from livestock manures have emerged as a serious social issue. In addition, more food wastes are being produced due to population growth and increased income level. Since the London Convention has banned the ocean dumping of wastes, some other waste treatment methods for land disposal had to be developed and applied. At the same time, researches have been conducted to develop alternative energy sources from various types of wastes. As a result, anaerobic digestion as a waste treatment method has become an attractive solution. In this study has three objectives: first, to identify the physical properties of the mixture of livestock wastewater and food waste when combining food waste treatment with the conventional livestock manure treatment based on anaerobic mesophilic digestion; second, to find the ideal ratio of waste mixture that could maximize the collection efficiency of methane ($CH_4$) from the anaerobic digestion process; and third, to promote $CH_4$ production by comparing the biodegradability. As a result of comparing the reactors R1, R2, and R3, each containing a mixture of food waste and livestock manure at the ratio of 5:5, 7:3, and 3:7, respectively, R2 showed the optimum treatment efficiencies for the removal of Total Solids (TS) and Volatile Solids (VS), $CH_4$ production, and biodegradability.

• 한국축산시설환경학회지
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• 제19권1호
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• pp.39-46
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• 2013

This study was carried out to compare the filtration effect of anaerobic digestion waste water by compost filtration bed. Three types of filtration systems were set for filtration test following to composition of bedding materials. Two filtration systems were filled with sawdust, rice-hull and wood-chip. And the other was filled with sawdust and rice-hull. Anaerobic digestion waste water was applied evenly on the surface of the filtration bed with spraying nozzle. The concentration of nitrogen, biochemical oxygen demand (BOD), suspended solids (SS) of anaerobic digestion waste water was decreased by filtration treatment. The total nitrogen content was decreased from 1,313 mg/L to 1,090~1,293 mg/L and BOD concentration was decreased from 529.7 mg/L to 125~162.3 mg/L, respectively. The SS content was decreased from 69~79% by filtration process. In addition, the electrical conductivity (EC) was decreased from 10.22 ds/m to 7.91~8.31 ds/m.

• 환경위생공학
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• 제13권1호
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• pp.16-25
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• 1998

Laboratory-scale experiment using anaerobic fluidized bed reactor was carried out to investigate the prehydrolysis step with caustic soda on the treatment efficiency of anaerobic sludge treatment, since the overall rate-limiting step for the complete anaerobic digestion of sludge was the hydrolysis step by extracellular bacterial enzymes of insoluble polymeric molecules. Reactors received a sludge which had not been pretreated, a 50-50 mixture of pretreated and untreated sludge, and the fully pretreated sludge. Hydraulic retention time of 10, 5, 2.5 days and 1 day were applied with an respective equivalent organic loading rate of 1.17, 2.23, 4.17, 11.24 gCOD/L/d. Reactor with the untreated sludge did not archieve adequate digestion even at the HRT of 5 days, and reactor, which received the 50-50 mixture, operated well at the HRT of 5 days, but began to show signs of unstable digestion at the HRT of 2.5 days. While, reactor, which was fed the hydrolyzed sludge, operated reasonably well at the 2.5 days, but was showing somewhat decrease in removal efficiencies. Results, therefore, have substantiated that the limiting reaction in the anaerobic treatment process is hydrolysis. The soluble COD did not significantly accumulate in the reactor as organic acid form, even when they were highly stressed. It was believed that this resistance to a build-up of organic acids and soluble COD behavior was mainly due to the maintenance of the methane bacteria in the fixed-film system which prevents washout as the organic loading increased. The anaerobic fluidized bed reactor was therefore effective for the digestion of waste activated sludge at short HRT.

• KSBB Journal
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• 제22권2호
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• pp.97-101
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• 2007

본 연구는 당 연구실에서 구축하고 있는 음식물쓰레기 고부가 자원화zero-emission시스템의 마지막 단계에 해당하는 부분으로써 본 공정의 부산물인 음식물 쓰레기 당화고형분과 박테리아 셀룰로오스배양 후의 여액을 기질 원으로 하여 2상 UASB 반응기를 이용하여 혐기성 소화를 수행하였다. 산 반응조와 메탄 반응조는 각각 35, 40$^{\circ}C$에서 운전하였고 두 반응조의 유기물 부하율은 각각 3g-VS/L${\cdot}$day, 25,000 mg/L로 유지하였다. 공정부산물의 최적 소화조건을 찾기 위하여 F.W + B.C.R, B.C.R, B.C.R + S.S 순으로 단계적으로 주입, 운전한 결과, 최종 메탄 발효액의 pH는 각각 7.13, 7.17, 7.22이었고 COD 제거율은 각각 88, 90, 91%이었으며 메탄 생성율은 각각 0.26, 0.34, $0.32m^3-CH_4/kg-COD_{remove}$이었다. 세번째 단계인 B.C.R + S.S를 기질로 사용한 경우가 음식물 쓰레기만 사용한 경우보다 전환효율이 높았다. 이는 음식물 쓰레기를 바로 혐기성 소화하는 것보다 음식물 쓰레기로부터 고부가가치를 창출하고 그 잔액으로 혐기성 소화를 거치는 방법이 보다 경제적이고 유익함을 알 수 있다. 따라서 당 실험실에서 구축하고 있는 음식물 쓰레기 고부가 자원화 zero-emission 시스템은 음식물 쓰레기에 포함된 에너지를 최대한 회수하고 고부가가치를 창출함에 있어서 가장 이상적인 방법이라고 사료된다.