Production of carboxylates from high rate activated sludge through fermentation

Cristina Cagnetta, Marta Coma, Siegfried E. Vlaeminck, Korneel Rabaey

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27 Citations (SciVal)
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The aim of this work was to study the key parameters affecting fermentation of high rate activated A-sludge to carboxylates, including pH, temperature, inoculum, sludge composition and iron content. The maximum volatile fatty acids production was 141 mg C g1 VSSfed, at pH 7. Subsequently the potential
for carboxylate and methane production for A-sludge from four different plants at pH 7 and 35 C were compared. Initial BOD of the sludge appeared to be key determining carboxylate yield from A-sludge. Whereas methanogenesis could be correlated linearly to the quantity of ferric used for coagulation, fermentation did not show a dependency on iron presence. This difference may enable a strategy
whereby A-stage sludge is separated to achieve fermentation, and iron dosing for phosphate removal is only implemented at the B-stage.
Original languageEnglish
Pages (from-to)165-172
Number of pages8
JournalBioresource Technology
Early online date21 Mar 2016
Publication statusPublished - Oct 2016


  • AB process
  • Anaerobic digestion
  • A-sludge
  • Iron
  • volatile fatty acids


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