Title
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Capture-ferment-upgrade : a three-step approach for the valorization of sewage organics as commodities
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Author
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Abstract
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This critical review outlines a roadmap for the conversion of chemical oxygen demand (COD) contained in sewage to commodities based on three-steps: capture COD as sludge, ferment it to volatile fatty acids (VFA), and upgrade VFA to products. The article analyzes the state-of-the-art of this three step approach and discusses the bottlenecks and challenges. The potential of this approach is illustrated for the European Union's 28 member states (EU-28) through Monte Carlo simulations. High-rate contact stabilization captures the highest amount of COD (66-86 g COD person equivalent(-1) day(-1) in 60% of the iterations). Combined with thermal hydrolysis, this would lead to a VFA-yield of 23-44 g COD person equivalent(-1) day(-1). Upgrading VFA generated by the EU-28 would allow, in 60% of the simulations, for a yearly production of 0.2-2.0 megatonnes of esters, 0.7-1.4 megatonnes of polyhydroxyalkanoates or 0.6-2.2 megatonnes of microbial protein substituting, respectively, 20-273%, 70-140% or 21-72% of their global counterparts (i.e., petrochemical-based esters, bioplastics or fishmeal). From these flows, we conclude that sewage has a strong potential as biorefinery feedstock, although research is needed to enhance capture, fermentation and upgrading efficiencies. These developments need to be supported by economic/environmental analyses and policies that incentivize a more sustainable management of our resources. |
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Language
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English
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Source (journal)
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Environmental science and technology / American Chemical Society. - Easton, Pa
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Publication
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Washington
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Amer chemical soc
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2018
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ISSN
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0013-936X
[print]
1520-5851
[online]
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DOI
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10.1021/ACS.EST.7B05712
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Volume/pages
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52
:12
(2018)
, p. 6729-6742
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ISI
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000436018900004
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Pubmed ID
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29772177
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Full text (Publisher's DOI)
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Full text (open access)
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Full text (publisher's version - intranet only)
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