The effect of CO enrichment in sewage sludge anaerobic digestion (AD) as a potential strategy to improve the biogas yield was assessed at increasing organic loading rates (OLR). Effects on process performance and resilience were evaluated in long-term continuous AD experiments at lab-scale. The specific methane production (SMP) was sustainably enhanced in the test digester compared to a control at elevated OLRs, reaching an increase of 6 ± 12% on average at the highest OLR tested (4.0 kg/(m·d)). The reduction of CO via homoacetogenesis, facilitating acetoclastic CH formation is proposed as the dominant conversion pathway. Results suggest that sufficient load of easily degradable substances is a prerequisite for intrinsic formation of the reduction equivalent H via acidogenesis. The enhanced resilience of the process under CO-enriched conditions in response to acid accumulation further qualifies this approach as a viable option for improving AD performance by converting a waste stream into a valuable product.
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http://dx.doi.org/10.1016/j.biortech.2021.125147 | DOI Listing |
Environ Sci Technol
January 2025
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China.
Pyrogenic carbons (PCs), with varying structures depending on the materials and thermal treatment conditions, have been extensively used to enhance anaerobic digestion by mediating electron transfer. However, the underlying mechanism has yet to be explored. Herein, the redirection and enhancement of the direct interspecies electron transfer (DIET) pathway were evidenced, along with the upregulated electrochemical properties and structural proteins in the methanogenic consortia.
View Article and Find Full Text PDFEnviron Microbiol
January 2025
Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu, China.
Anaerobic digestion (AD) of organic wastes relies on the interaction and cooperation of various microorganisms. Phages are crucial components of the microbial community in AD systems, but their diversity and interactions with the prokaryotic populations are still inadequately comprehended. In this study, 2121 viral operational taxonomic units (vOTUs) were recovered from 12 anaerobic fatty acid-fed reactors.
View Article and Find Full Text PDFWater Res X
May 2025
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China.
Although the treatment of sludge with free nitrous acid can effectively recover short chain fatty acids, the feasibility of sequential nitrite reduction and methane recovery without acidic pH adjustment is still scarcely studied. Therefore, this study aimed to provide insights into the effect of nitrite at different levels on nitrite reduction and methane production. The results showed that the nitrite concentrations of 100, 200, 400 and 800 mg/L were completely reduced in 1, 2, 2 and 4 days, respectively.
View Article and Find Full Text PDFSci Total Environ
January 2025
Leiden University, Institute of Environmental Science - Industrial Ecology, Van Steenisgebouw, Einsteinweg 2, 2333 CC Leiden, the Netherlands. Electronic address:
In this study, we compared the Sol-Char sanitation system with an Anaerobic Digestion (AD) system using Life Cycle Assessment (LCA) to evaluate their environmental impacts. Since both systems offer opportunities for human waste treatment and resource recovery, understanding their performance is crucial. This comparison aims to determine their environmental impacts while considering diverse factors, such as energy production and nutrient recovery.
View Article and Find Full Text PDFBioresour Technol
January 2025
Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore, 637141, Singapore.
The improvement of biogas production in anaerobic digestion (AD) by biochar introduction has been demonstrated. However, the distribution of biochar in the digester and its effect on AD have been seldom explored. In this study, the distribution of biochar and their impact on AD were investigated in a 30 L semi-continuously operated bench-scale anaerobic digester.
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