Effect of post-digestion temperature on serial CSTR biogas reactor performance

Kanokwan Boe, Dimitar Borisov Karakashev, Eric Trably, Irini Angelidaki

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The effect of post-digestion temperature on a lab-scale serial continuous-flow stirred tank reactor (CSTR) system performance was investigated. The system consisted of a main reactor operated at 55 degrees C with hydraulic retention time (HRT) of 15 days followed by post-digestion reactors with HRT of 5.3 days. Three post-digestion temperatures (55 degrees C, 37 degrees C and 15 degrees C) were compared in terms of biogas production, process stability, microbial community and methanogenic activity, The results showed that the post-digesters operated at 55 degrees C, 37 degrees C and 15 degrees C gave extra biogas production of 11.7%, 8.4% and 1.2%, respectively. The post-digester operated at 55 degrees C had the highest biogas production and was the most stable in terms of low VFA concentrations. The specific methanogenic activity tests revealed that the main reactor and the post-digester operated at 55 degrees C and 37 degrees C had very active acidogens and methanogens, In contrast, very low methanogenic activity was observed at 15 degrees C.
Original languageEnglish
JournalWater Research
Issue number3
Pages (from-to)669-676
Publication statusPublished - 2009


  • Post-digestion
  • Temperature
  • Biogas

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