• 실내환경 및 냄새 학회지
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• 제16권2호
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• pp.139-149
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• 2017

In order to reduce odor and methane emission from the landfill, open biocovers and a closed biofilter were applied to the landfill site. Three biocovers and the biofilter are suitable for relatively small-sized landfills with facilities that cannot resource methane into recovery due to small volumes of methane emission. Biocover-1 consists only of the soil of the landfill site while biocover-2 is mixed with the earthworm casts and artificial soil (perlite). The biofilter formed a bio-layer by adding mixed food waste compost as packing material of biocover-2. The removal efficiency decreased over time on biocover-1. However, biocover-2 and the biofilter showed stable odor removal efficiency. The rates of methane removal efficiency were in order of biofilter (94.9%)>, biocover-1(42.3%)>, and biocover-2 (37.0%). The methane removal efficiency over time in biocover-1 was gradually decreased. However, drastic efficiency decline was observed in biocover-2 due to the hardening process. As a result of overturning the surface soil where the hardening process was observed, methane removal efficiency increased again. The biofilter showed stable methane removal efficiency without degradation. The estimate methane oxidation rate in biocover-1 was an average of 10.4%. Biocover-2 showed an efficiency of 46.3% after 25 days of forming biocover. However, due to hardening process efficiency dropped to 4.6%. After overturn of the surface soil, the rate subsequently increased to 17.9%, with an evaluated average of 12.5%.

• 한국미생물·생명공학회지
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• 제40권1호
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• pp.76-81
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• 2012

Removal of methane, benzene and toluene was evaluated in a lab-scale biocover packed with a soil mixture of forest soil and earthworm cast (75:25 weight ratio). The bacterial community in the biocover was characterized using quantitative real-time PCR and terminal restriction fragment length polymorphism. Methane was removed at the upper layer of the biocover (-0.1 ~ -0.4 m), where the oxygen concentration was remarkably lower. The average removal efficiencies for methane and benzene/toluene were 90% and 99%, respectively. The pmoA gene copy numbers, responsible for methane oxidation, in the upper layer were higher than those in the lower layer. While type I methanotrohs dominated the lower layer, type II methanotrophs, such as Methylocystis and Methylosinus, were noted to be predominant in the upper layer. Benzene and toluene were removed from the lower layer (-0.6 ~ -0.9 m) as well as the upper layer. Moreover, the tmoA gene copy number, responsible for benzene/toluene oxidation, seen in the upper layer was not significantly different from those seen in the lower layer. These results suggest that a biocover packed with a soil and earthworm cast mixture is a promising method which could be utilized for the control of methane and volatile organic compounds such as benzene and toluene.

• Journal of Microbiology and Biotechnology
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• 제31권6호
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• pp.803-814
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• 2021

A pilot-scale biocover was constructed at a sanitary landfill and the mitigation of methane and odor compounds was compared between the summer and non-summer seasons. The average inlet methane concentrations were 22.0%, 16.3%, and 31.3%, and the outlet concentrations were 0.1%, 0.1%, and 0.2% during winter, spring, and summer, respectively. The odor removal efficiency was 98.0% during summer, compared to 96.6% and 99.6% during winter and spring, respectively. No deterioration in methane and odor removal performance was observed even when the internal temperature of the biocover increased to more than 40℃ at midday during summer. During summer, the packing material simultaneously degraded methane and dimethyl sulfide (DMS) under both moderately thermophilic (40-50℃) and mesophilic conditions (30℃). Hyphomicrobium and Brevibacillus, which can degrade methane and DMS at 40℃ and 50℃, were isolated. The diversity of the bacterial community in the biocover during summer did not decrease significantly compared to other seasons. The thermophilic environment of the biocover during summer promoted the growth of thermotolerant and thermophilic bacterial populations. In particular, the major methane-oxidizing species were Methylocaldum spp. during summer and Methylobacter spp. during the non-summer seasons. The performance of the biocover remained stable under moderately thermophilic conditions due to the replacement of the main species and the maintenance of bacterial diversity. The information obtained in this study could be used to design biological processes for methane and odor removal during summer and/or in subtropical countries.

• 한국미생물·생명공학회지
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• 제37권4호
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• pp.293-305
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• 2009

메탄은 온실효과가 이산화탄소 보다 20배 이상인 대표적인 non-$CO_2$ 온실가스이다. 매립지는 주요 인위적 메탄 발생원으로, 매립지의 메탄 발생량은 연간 35~73 Tg(tera gram)으로 추정된다. 바이오커버(개방형 시스템)과 바이오필터(폐쇄형 시스템)을 이용하는 생물학적 방법은 메탄을 회수하여 자원화하기에는 메탄 농도가 너무 낮거나 가스 포집정이 설치되어 있지 않는 노후화된 매립지나 소규모 매립지로부터 메탄 배출을 저감할 수 있는 유용한 방법이다. 메탄을 유일탄소원과 에너지원으로 활용하는 메탄산화세균은 이러한 생물학적 방법에 있어 메탄을 산화시켜 제거하는데 매우 중요한 역할을 담당한다. 토양, compost, 지렁이 분변토 등과 같은 다양한 충전재를 이용하여 실험실 규모의 바이오커버/바이오필터의 메탄산화효율에 관한 많은 연구가 진행되었다. 이 중에서 compost는 가장 많이 이용되고 있는 충전재이고, compost를 이용한 바이오커버/바이오필터의 메탄산화속도는 50에서 $700\;g-CH_4\;m^{-2}\;d^{-1}$로 보고되고 있다. 또한, 실제 매립지에 파일럿 규모의 바이오커버/바이오필터를 설치하여 메탄 배출 저감 효과에 관한 연구도 진행되고 있다. 매립지의 메탄 배출 저감은 탄소배출권 거래와 연관될 수 있으므로, 바이오커버/바이오필터에 의한 메탄 저감량을 정확하게 평가하는 것이 매우 중요하다. 그러므로, 매립지 현장에 설치된 바이오커버/바이오필터의 성능을 평가하는 방법은 표준화되어야 하며, 메탄 저감량을 정확하게 정량화할 수 있는 방법 개발이 필요하다.

• 한국미생물·생명공학회지
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• 제45권4호
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• pp.322-329
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• 2017

본 연구에서는 생활 폐기물 매립지 현장에 파일럿 규모의 바이오커버(pilot-scale biocover, PBC) 2기를 설치하고, 240일 동안 메탄 제거 효율을 모니터링하였다. 또한, 바이오커버 충전 소재를 채취하여 혈청병에서 잠재 메탄 산화능을 평가하였다. 바이오커버로 유입되는 메탄 농도는 23.7-47.9%(평균 값 = 41.3%, 중간값 = 42.6%) 수준이었다. 토양, 지렁이 분변토 및 퇴비 혼합물(7:2:1, v/v)을 충전 소재로 구축한 PBC1의 메탄 제거 효율은 60.7-85.5%이었다. 토양, 지렁이 분변토, perlite 및 퇴비 혼합물(4:2:3:1, v/v)을 충전 소재로 구축한 PBC2의 표메탄 제거 효율은 29.2-78.5%이었다. 그러나, 바이오커버의 충전 소재 자체의 메탄 잠재 산화 능력이 우수함에도 불구하고(평균메탄산화속도 = $180-199{\mu}g\;CH_4{\cdot}g\;packing\;material^{-1}{\cdot}h^{-1}$), 충전 소재의 다짐현상과 채널링이 발생하면 PBC1과 PBC2의 메탄 제거 효율은 0-30%로 저하되었다. 한편, 바이오커버의 메탄 제거 효율은 계절(외부 기온)에 따른 유의적인 차이를 보이지 않았다. 본 연구로부터 도출된 결과는 향후 매립지 현장에 실규모의 메탄 저감용 바이오커버를 설계하고 운전 조건을 구축하는데 유용하게 활용 가능하다.