Phosphorus recovery from sewage sludge ash through an electrodialytic process

Paula Guedes, Nazare Couto, Lisbeth M. Ottosen, Alexandra B. Ribeiro

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The electrodialytic separation process (ED) was applied to sewage sludge ash (SSA) aiming at phosphorus (P) recovery. As the SSA may have high heavy metals contents, their removal was also assessed. Two SSA were sampled, one immediately after incineration (SA) and the other from an open deposit (SB). Both samples were ED treated as stirred suspensions in sulphuric acid for 3,7 and 14 days. After 14 days, phosphorus was mainly mobilized towards the anode end (approx. 60% in the SA and 70% in the SB), whereas heavy metals mainly electromigrated towards the cathode end. The anolyte presented a composition of 98% of P, mainly as orthophosphate, and 2% of heavy metals. The highest heavy metal removal was achieved for Cu (ca. 80%) and the lowest for Pb and Fe (between 4% and 6%). The ED showed to be a viable method for phosphorus recovery from SSA, as it promotes the separation of P from the heavy metals. (C) 2014 Elsevier Ltd. All rights reserved.
Original languageEnglish
JournalWaste Management
Volume34
Issue number5
Pages (from-to)886-892
Number of pages7
ISSN0956-053X
DOIs
Publication statusPublished - 2014

Keywords

  • Sewage sludge ash
  • Electrodialytic separation
  • Heavy metals
  • Phosphorus

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