In this study, temporal impacts of thermal, alkaline/acid and thermal-alkaline sludge pre-treatments on digestion performance and microbiome were investigated and compared in methanogenic sludge digesters. Results showed that thermal and alkaline/acid pre-treatments were efficient in releasing intracellular and EPS organic matter, respectively. The thermal-alkaline pre-treatment showed synergistic impacts of both thermal and alkaline/acid pre-treatments by releasing the major portion of sludge organic matter from solid- to liquid-phase, which result in 60-65% organic carbon removal in subsequent sludge digestion and further optimizing digestion temperature had negligible improvement. The 16S rRNA gene-based analyses suggested that organic matter released from sludge pre-treatments is a major deterministic parameter in shaping sludge microbiome. Pre-treatment specific lineages were identified in different sludge digesters, whereas several taxa were identified as common functionally active populations in sludge digestion. This study provided mechanistic insights into impacts of pre-treatments on digestion performance and microbiome in methanogenic sludge digesters.
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http://dx.doi.org/10.1016/j.biortech.2020.123909 | DOI Listing |
Chemosphere
January 2025
DICAR University of Pavia, 27100 Pavia, Italy. Electronic address:
Excess biological sludge processing and disposal have a significant impact on the energy balance and economics of wastewater treatment operations, and on receiving environments. Anaerobic digestion is probably the most widespread in-plant sludge processing method globally, since it stabilizes and converts biosolids organic matter into biogas, allowing partial recovery of their embedded chemical energy. A considerable number of studies concerning applicable techniques to improve biogas production, both in quantity and quality, include pre-treatment strategies to promote biosolids disintegration aimed at the release and solubilisation of intracellular energy compounds, inorganic/biological amendments aimed at improving process performance, and sludge thermal pre-treatment.
View Article and Find Full Text PDFEnviron Microbiol
January 2025
Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
Shotgun and proximity-ligation metagenomic sequencing were used to generate thousands of metagenome assembled genomes (MAGs) from the untreated wastewater, activated sludge bioreactors, and anaerobic digesters from two full-scale municipal wastewater treatment facilities. Analysis of the antibiotic resistance genes (ARGs) in the pool of contigs from the shotgun metagenomic sequences revealed significantly different relative abundances and types of ARGs in the untreated wastewaster compared to the activated sludge bioreactors or the anaerobic digesters (p < 0.05).
View Article and Find Full Text PDFEnviron Res
January 2025
Research & Development Institute in Shenzhen, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, China. Electronic address:
Adding additives exogenously is an effective strategy to enhance methanogenic activity and improve AD stability. Corn straw-based biochar@MIL-88A(Fe) (BM) was synthesized herewith and used as an exogenous additive to boost methane (CH) production. After adding BM at 250 mg/g WAS VS, the accumulative CH production and maximum CH yield increased by 1.
View Article and Find Full Text PDFSci Total Environ
January 2025
CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal; LABBELS - Associate Laboratory, Guimarães, Braga, Portugal. Electronic address:
The conversion of organic matter to methane through anaerobic digestion (AD) process can be enhanced by different materials. However, literature reports show inconsistent results on the effect of materials in different AD systems. In this study, we evaluated the influence of the inoculum's activity on methane production (MP) efficiency in the presence of different materials (activated carbon (AC), magnetite (Mag), and zeolite (Zeo)).
View Article and Find Full Text PDFJ Environ Manage
January 2025
Bioenergy Research Institute - IPBEN, UNESP, Institute of Chemistry, Araraquara, SP, Brazil; São Paulo State University (UNESP), Institute of Chemistry, Campus Araraquara, Department of Engineering, Physics and Mathematics, Rua Prof. Francisco Degni, 55, 14800-900, Araraquara, SP, Brazil. Electronic address:
Waste-to-energy technologies involve the conversion of several wastes to useful energy forms like biogas and biochar, which include biological and thermochemical processes, as well as the combination of both systems. Assessing the economic and environmental impacts is an important step to integrate sustainability and economic viability at anaerobic digestion systems and its waste management. Energy production, CO emissions, cost analysis, and an overall process evaluation were conducted, relying on findings from both laboratory and pilot-scale experiments.
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