Characterisation of ashes from waste biomass power plants and phosphorus recovery

Lijian Leng, Anna Bogush, Amitava Roy, Julia Stegemann

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2 Citations (Scopus)

Abstract

Biowastes, such as meat and bone meal (MBM), and poultry litter (PL), are used as energy sources for industrial combustion in the UK. However, the biomass ashes remaining after combustion, which contain nutrients such as phosphorus, are landfilled rather than utilised. To promote their utilisation, biomass ashes from industries were characterised in terms of their elemental and mineral compositions, phosphorus extractability, and pH-dependent leachability. These ashes were highly alkaline (pH as high as 13), and rich in calcium and phosphorus. The P bio-availabilities in the ash evaluated by Olsen's extraction were low. Hydroxyapatite and potassium sodium calcium phosphate were identified by X-ray powder diffraction (XRD) as the major phases in the MBM and PL ashes, respectively. The leaching of P, Ca, and many other elements was pH dependent, with considerable increase in leaching below about pH 6. P recovery by acid dissolution (e.g., with H2SO4) seems feasible and promising; the optimized acid consumption for ~90% P recovery could be as low as 3.2–5.3 mol H+/mol P.
Original languageEnglish
Pages (from-to)573-583
Number of pages11
JournalScience of the Total Environment
Volume690
Early online date21 Jun 2019
DOIs
Publication statusPublished - 10 Nov 2019
Externally publishedYes

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Keywords

  • Incineration
  • Fertiliser
  • Phosphorus recovery
  • Acid neutralization capacity
  • Animal manure

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