Characterization of the Bacterial Community Associated with Methane and Odor in a Pilot-Scale Landfill Biocover under Moderately Thermophilic Conditions

Abstract

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°C at midday during summer. During summer, the packing material simultaneously degraded methane and dimethyl sulfide (DMS) under both moderately thermophilic (40-50°C) and mesophilic conditions (30°C). Hyphomicrobium and Brevibacillus, which can degrade methane and DMS at 40°C and 50°C, 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 methaneoxidizing species were Methylocaldum spp. during summer and Methylobacter spp. during the nonsummer 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.

Dynamics of Functional Genes and Bacterial Community during Bioremediation of Diesel-Contaminated Soil Amended with Compost

“…The effects of compost amendment upon the CH 4 oxidation and N 2 O reduction potentials of diesel-contaminated soil during bioremediation were investigated using the same methods as in previous studies [ 24 , 26 , 27 ]. Thus, the soil sample (2 g) was inoculated into nitrate minimal salt medium (NMS, 6 ml) in a 120-ml serum bottle [ 24 , 27 ].…”

“…The effects of compost amendment upon the CH 4 oxidation and N 2 O reduction potentials of diesel-contaminated soil during bioremediation were investigated using the same methods as in previous studies [ 24 , 26 , 27 ]. Thus, the soil sample (2 g) was inoculated into nitrate minimal salt medium (NMS, 6 ml) in a 120-ml serum bottle [ 24 , 27 ]. The bottle was then sealed with a butyl rubber cap, and 50,000 ppm (v/v) of CH 4 gas (99.99%, Dong-A Specialty Gases Co., Korea) was injected into the headspace of the bottle.…”

“…The bottle was then sealed with a butyl rubber cap, and 50,000 ppm (v/v) of CH 4 gas (99.99%, Dong-A Specialty Gases Co., Korea) was injected into the headspace of the bottle. While incubating the bottle at 30°C and 150 rpm, the CH 4 concentration in the headspace was measured using a gas chromatograph (7890A, Agilent Technologies, USA) [ 24 , 27 ].…”

“…The qPCR was performed to evaluate the change in functional gene abundances during the bioremediation of dieselcontaminated soil amended with various ratios of compost. For this procedure, DNA was extracted from the soil sample using a NucleoSpin Soil kit (Macherey-Nagel GmbH, Düren, Germany) (Yang et al 2021). The 16S rRNA gene was quantitatively evaluated for total bacteria abundances using 340F and 805R primer sets (Kim et al 2012).…”

“…Erythrobacter has been shown to degrade petroleum, and its relative abundance was shown to increase with time during the bioaugmentation of petroleum-contaminated seawater (Shi et al 2020). Hypomicrobium, a methylotrophic bacterium, was one of the dominant bacteria in a biocover used for the simultaneous removal of CH 4 and odor (Yang et al 2021). In another study, Hypomicrobium was shown to oxidize a high concentration of CH 4 (100,000 ppm) in a batch reactor (Jeong and Kim 2019).…”