Hydrothermal carbonization (HTC) of sewage sludge has been investigated in this study to demonstrate its capability to segregate phosphorous element and produce a solid energy dense material, i.e. hydrochar, which could find application as solid bio-fuel and/or soil amendment. In this study, centrifuged anaerobically digested sewage sludge (total solid content: 21 wt.%) from Trento North (Italy) waste water treatment plant was hydrothermally carbonized at 190 and 210 °C at 1 and 3 h of residence time. Hydrochars, recovered via filtration, were leached using 4 M HCl solution at room temperature to transfer phosphorous (P) and inorganic elements into the aqueous solution. Recovery of P was achieved via phosphate salt precipitation by alkalinisation, up to pH 9, of the acidic leachate using a 5 M NaOH solution. Sewage sludge and the corresponding hydrochars, before and after acid leaching, were characterized in terms of energy properties (HHV) by calorimetric analysis, P and inorganic elements content via ICP-OES. Results showed that HTC promotes segregation of P element in the hydrochar (up to 90 wt.% of the initial content on a dry basis at 190 °C, 1 h). The study demonstrated that P can be effectively recovered via precipitation via acidic leaching and subsequent alkalization with total recovery yields higher than 70 wt.%. The hydrochar residues, after leaching, showed inorganic elements content and energy properties compatible with their possible use as soil amendment in agriculture and/or as solid biofuel.

Hydrothermal carbonization as an efficient tool for sewage sludge valorization and phosphorous recovery / Volpe, M.; Fiori, L.; Merzari, F.; Messineo, A.; Andreottola, G.. - In: CHEMICAL ENGINEERING TRANSACTIONS. - ISSN 2283-9216. - STAMPA. - 80:(2020), pp. 199-204. [10.3303/CET2080034]

Hydrothermal carbonization as an efficient tool for sewage sludge valorization and phosphorous recovery

Volpe M.;Fiori L.;Merzari F.;Andreottola G.
2020-01-01

Abstract

Hydrothermal carbonization (HTC) of sewage sludge has been investigated in this study to demonstrate its capability to segregate phosphorous element and produce a solid energy dense material, i.e. hydrochar, which could find application as solid bio-fuel and/or soil amendment. In this study, centrifuged anaerobically digested sewage sludge (total solid content: 21 wt.%) from Trento North (Italy) waste water treatment plant was hydrothermally carbonized at 190 and 210 °C at 1 and 3 h of residence time. Hydrochars, recovered via filtration, were leached using 4 M HCl solution at room temperature to transfer phosphorous (P) and inorganic elements into the aqueous solution. Recovery of P was achieved via phosphate salt precipitation by alkalinisation, up to pH 9, of the acidic leachate using a 5 M NaOH solution. Sewage sludge and the corresponding hydrochars, before and after acid leaching, were characterized in terms of energy properties (HHV) by calorimetric analysis, P and inorganic elements content via ICP-OES. Results showed that HTC promotes segregation of P element in the hydrochar (up to 90 wt.% of the initial content on a dry basis at 190 °C, 1 h). The study demonstrated that P can be effectively recovered via precipitation via acidic leaching and subsequent alkalization with total recovery yields higher than 70 wt.%. The hydrochar residues, after leaching, showed inorganic elements content and energy properties compatible with their possible use as soil amendment in agriculture and/or as solid biofuel.
2020
Volpe, M.; Fiori, L.; Merzari, F.; Messineo, A.; Andreottola, G.
Hydrothermal carbonization as an efficient tool for sewage sludge valorization and phosphorous recovery / Volpe, M.; Fiori, L.; Merzari, F.; Messineo, A.; Andreottola, G.. - In: CHEMICAL ENGINEERING TRANSACTIONS. - ISSN 2283-9216. - STAMPA. - 80:(2020), pp. 199-204. [10.3303/CET2080034]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/285953
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