Electrodialytic extraction of phosphorus from ash of low-temperature gasification of sewage sludge

Bidragets oversatte titel: Elektrolytisk ekstraktion af fosfor fra lav-temperatur forgasningsaske produceret på spildevandsslam

Raimon Parés Viader, Pernille Erland Jensen, Lisbeth M. Ottosen, Jesper Ahrenfeldt, Henrik Hauggaard-Nielsen

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Abstract

Low-temperature gasification allows the production of energy from biomass with high contents of low melting point compounds, like sewage sludge, and the recycling of the nutrients as P from the resulting ashes as renewable fertiliser. Major drawbacks are, however, the presence of heavy metals and the low plant-availability of Al- and Fe- phosphate compounds in the gasification ashes. In the present research, the feasibility of a 2-compartment electrodialytic (ED) setup for P separation from Al, Fe and heavy metals in two different low-temperature gasification ashes was investigated. One ash was from gasification of sewage sludge where P was precipitated with Fe and Al salts, from which it was possible to extract up to 26% of the P. The other ash was from co-gasification of a mixture of biologically precipitated sewage sludge and wheat straw pellets. More promising results were obtained with this ash, as up to 90% of the P was extracted from the ashes. For both ashes, P was extracted by ED in acidic aqueous solutions with ratios of Fe, Al and each heavy metal to P considerably below the values found in the initial ashes. Therefore, the 2-compartment ED cell technology was proved as possible method to separate Al, Fe and heavy metals from P for low-temperature gasification ashes
OriginalsprogEngelsk
TidsskriftElectrochimica Acta
Vol/bind181
Sider (fra-til)100-108
ISSN0013-4686
DOI
StatusUdgivet - 2015

Emneord

  • Fosfor
  • Spildevandsslam
  • Lav-temperatur forgasning
  • Tungmetaller
  • Elektrolyse

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