Sequenced anaerobic-aerobic treatment of hemp black liquors

S. Kortekaas, H. S. Doma, S. A. Potapenko, J. A. Field, G. Lettinga

Research output: Contribution to journalConference articlepeer-review

23 Scopus citations


This study evaluates the sequenced anaerobic-aerobic treatment of hemp bark and hemp stem wood black liquors with respect to COD removal efficiency and detoxification. Anaerobic toxicity assays revealed that soda pulping liquors derived from hemp are just as toxic as those derived from wood. Hemp bark and stem wood black liquors caused 50% inhibition at concentrations of 5.9 and 4.5 g COD/l, respectively. Long term experiments were conducted in lab-scale upflow anaerobic sludge blanket (UASB) reactors at 30°C. Black liquor was fed at sub-toxic concentrations (< 4 g COD/l). In the bark column loadings were applied up to 17.5 g COD/l(*)d with COD and BOD5 efficiencies of 56.0 and 87.9%, respectively. In the stem wood column loadings up to 18.4 g COD/l(*)d were reached with COD and BOD5 efficiencies of 42.3 and 81.0%, respectively. Aerobic post-treatment displayed only minor extra COD removal and a strong increase of color levels. After sequenced anaerobic-aerobic treatment, the COD removal was 70.9 and 58.4% for bark and stem wood liquor, respectively, whereas the BOD5 removal exceeded 98%. Strong detoxification was accomplished after anaerobic-aerobic treatment, as was demonstrated by anaerobic toxicity assays. After anaerobic-aerobic treatment hemp bark and stem wood black liquors caused 50% inhibition at concentrations of 13.5 and 21.5 g COD/l, respectively.

Original languageEnglish (US)
Pages (from-to)409-419
Number of pages11
JournalWater Science and Technology
Issue number5-6
StatePublished - 1994
EventProceedings of the 4th IAWQ Symposium on Forest Industry Wastewaters - Tampere, Finl
Duration: Jun 8 1993Jun 11 1993


  • Anaerobic-aerobic
  • Biodegradation
  • Biological treatment
  • Detoxification
  • Hemp
  • Methanogenic toxicity
  • Soda pulping

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology


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