Process Waters from Hydrothermal Carbonization of Sludge: Characteristics and Possible Valorization Pathways

Michela Langone and Daniele Basso
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Michela Langone: Laboratory of Technologies for the efficient use and management of water and wastewater, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), 00123 Roma, Italy
Daniele Basso: HBI S.r.l., 39100 Bolzano, Italy

IJERPH, 2020, vol. 17, issue 18, 1-33

Abstract: Hydrothermal carbonization (HTC) is an innovative process capable of converting wet biodegradable residues into value-added materials, such as hydrochar. HTC has been studied for decades, however, a lack of detailed information on the production and composition of the process water has been highlighted by several authors. In this paper the state of the art of the knowledge on this by-product is analyzed, with attention to HTC applied to municipal and agro-industrial anaerobic digestion digestate. The chemical and physical characteristics of the process water obtained at different HTC conditions are compared along with pH, color, organic matter, nutrients, heavy metals and toxic compounds. The possibility of recovering nutrients and other valorization pathways is analyzed and technical feasibility constraints are reported. Finally, the paper describes the main companies which are investing actively in proposing HTC technology towards improving an effective process water valorization.

Keywords: digestate; hydrothermal carbonization (HTC); HTC chemicals; process waters; sewage sludge (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (9)

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