Enhancing the performance of anaerobic digestion of dairy manure through phase-separation

Yilmaz V., Demirer G. N.

CLEAN-SOIL AIR WATER, vol.36, no.9, pp.760-766, 2008 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 36 Issue: 9
  • Publication Date: 2008
  • Doi Number: 10.1002/clen.200800024
  • Journal Name: CLEAN-SOIL AIR WATER
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.760-766


Anaerobic digestion (AD) is an effective way to convert animal manures into profitable by-products while simultaneously reducing, the pollution of water, air, and soil caused by these wastes. Conventional high-rate anaerobic reactors cannot effectively process animal manures with high solids-containing wastes. The two-phase configuration for AD has several advantages over conventional one-phase processes, e.g., increased stability of the process, smaller size and cost efficient process configurations. In the present study, the experiments were carried out in a two-phase system composed of an acidogenic reactor and a methanogenic reactor, and in a one-phase system composed of only a methanogenic reactor. The reactors were operated as unmixed (without an external mixing aid), unsophisticated, and daily-fed mode. It was found that the two-phase configuration was more efficient than the one-phase system. The biogas production in the two-phase system at a hydraulic retention time (HRT) of 8.6 days (only methanogenic phase) was calculated to be 42% higher at an organic loading rate (OLR) of 3.5 g VS/L . day than that of the one-phase with a HRT of 20 days. This translates into significant performance improvement and reduced volume requirement. This finding represents a further step in the achievement of wider use of simple anaerobic reactor configurations for waste treatment in rural areas.