Use of methanotrophically activated biochar in novel biogeochemical cover system for carbon sequestration: Microbial characterization

Jyoti K Chetri; Krishna R Reddy; Stefan J Green

doi:10.1016/j.scitotenv.2022.153429

Use of methanotrophically activated biochar in novel biogeochemical cover system for carbon sequestration: Microbial characterization

Sci Total Environ. 2022 May 15:821:153429. doi: 10.1016/j.scitotenv.2022.153429. Epub 2022 Jan 29.

Authors

Jyoti K Chetri¹, Krishna R Reddy², Stefan J Green³

Affiliations

¹ University of Illinois at Chicago, Department of Civil, Materials, and Environmental Engineering, 842 West Taylor Street, Chicago, IL 60607, USA. Electronic address: jkc4@uic.edu.
² University of Illinois at Chicago, Department of Civil, Materials, and Environmental Engineering, 842 West Taylor Street, Chicago, IL 60607, USA. Electronic address: kreddy@uic.edu.
³ Genomics and Microbiome Core Facility, Rush University Medical Center, 1653 W. Congress Parkway, Jelke Building, Room 444, Chicago, IL 60612, USA. Electronic address: Stefan_Green@rush.edu.

PMID: 35101512
DOI: 10.1016/j.scitotenv.2022.153429

Abstract

Biochar-amended soils have been explored to enhance microbial methane (CH₄) oxidation in landfill cover systems. Recently, research priorities have expanded to include the mitigation of other components of landfill gas such as carbon dioxide (CO₂) and hydrogen sulfide (H₂S) along with CH₄. In this study, column tests were performed to simulate the newly proposed biogeochemical cover systems, which incorporate biochar-amended soil for CH₄ oxidation and basic oxygen furnace (BOF) slag for CO₂ and H₂S mitigation, to evaluate the effect of cover configuration on microbial CH₄ oxidation and community composition. Biogeochemical covers included a biochar-amended soil (10% w/w), and methanotroph-enriched activated biochar amended soil (5% or 10% w/w) as a biocover layer or CH₄ oxidation layer. The primary outcome measures of interest were CH₄ oxidation rates and the structure and abundance of methane-oxidation bacteria in the covers. All column reactors were active in CH₄ oxidation, but columns containing activated biochar-amended soils had higher CH₄ oxidation rates (133 to 143 μg CH₄ g^-1 day^-1) than those containing non-activated biochar-amended soil (50 μg CH₄ g^-1 day^-1) and no-biochar soil or control soil (43 μg CH₄ g^-1 day^-1). All treatments showed significant increases in the relative abundance of methanotrophs from an average relative abundance of 5.6% before incubation to a maximum of 45% following incubation. In activated biochar, the abundance of Type II methanotrophs, primarily Methylocystis and Methylosinus, was greater than that of Type I methanotrophs (Methylobacter) due to which activated biochar-amended soils also showed higher abundance of Type II methanotrophs. Overall, biogeochemical cover profiles showed promising potential for CH₄ oxidation without any adverse effect on microbial community composition and methane oxidation. Biochar activation led to an alteration of the dominant methanotrophic communities and increased CH₄ oxidation.

Keywords: Activated biochar; Biochar; Biogeochemical cover; Methane oxidation; Methanotrophs.

MeSH terms

Carbon Sequestration*
Charcoal / chemistry
Methane / chemistry
Oxidation-Reduction
Soil / chemistry
Soil Microbiology*
Waste Disposal Facilities

Substances

Soil
biochar
Charcoal
Methane