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The rise in human population and the advent of biological wastewater treatment has led to increased biosolid production, which requires sustainable solutions to mitigate potential negative impacts associated with the disposal of biosolids. Biosolid land application has the potential to decrease reliance on synthetic fertilizers and improve soil fertility; however, the microbial activity and associated greenhouse gas (GHG) emissions need to be evaluated to ensure there are no negative externalities of this approach. To address these issues, this study aimed to (i) assess the potential of a biosolid-amended soil system to emit nitrous oxide (N2O), (ii) quantify actual field GHG emissions from biosolid-amended soils, and (iii) evaluate a process-based model to predict these soil GHG emissions. This study performed a comprehensive analysis, including laboratory (potential assays and gene abundances), field (static chamber GHG measurements), and modeling (process-based) approaches, to understand the effect of biosolids on soil GHG emissions. We found that biosolid application increased soil nitrate and organic matter, and decreased soil pH in the short-term. Together, the changes in soil conditions promoted more denitrification, which became more complete with laboratory potential dinitrogen higher than nitrous oxide as the end-product over time. In the field, GHG emissions were generally higher in biosolid-amended soils, particularly just after biosolid application. While the predictive model was able to simulate general trends for field GHG emissions, it often underpredicted the magnitude of these emissions. Overall, despite initial increases in GHG, biosolids have the potential as a sustainable amendment to improve soil health and mitigate GHG emissions in agricultural practices over the long term. This research contributes to understanding biosolid use in promoting environmental sustainability and offers insights for future agricultural management strategies.
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Potential for improving nutrient use efficiencies of human food systems with a circular economy of organic wastes and fertilizer
Abstract Waste from the human food system includes a large quantity of nutrients that pose environmental and human health risks. If these nutrients can be captured and repurposed, they could potentially offset synthetic fertilizer demands. This study reviews several technologies—including anaerobic digestion, hydrothermal carbonization (HTC), and composting—that can be used to process wastes from the human food system. This study also assesses the quantity of nutrient resources that are available from wastes, including food waste, biosolids, manure, and yard waste. Three geographic scales were analyzed. At a national level in the United States, up to 27% of nitrogen and 33% of phosphorus demands for agriculture could be met with wastes from the human food system, primarily from food waste and biosolids. Some rural localities have a greater potential for circular economies of nutrients in the food system, with the potential to meet 100% of nitrogen and phosphorus fertilizer demands using waste nutrients, as in the case of Athens County, Ohio. Benefits of offsetting synthetic fertilizer use with waste nutrients include reduced greenhouse gas (GHG) emissions, with up to 64% reduction in GHG emissions per unit of nitrogen fertilizer produced with HTC.
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- PAR ID:
- 10560004
- Publisher / Repository:
- Purpose-led Publishing
- Date Published:
- Journal Name:
- Environmental Research Letters
- Volume:
- 19
- Issue:
- 9
- ISSN:
- 1748-9326
- Page Range / eLocation ID:
- 093002
- Subject(s) / Keyword(s):
- food waste biosolid anaerobic digestion hydrothermal carbonization greenhouse gas emissions nitrogen phosphorus
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1088/1748-9326/ad6617
