Co-digestion of sewage sludge and sterilized solid slaughterhouse waste: methane production efficiency and process limitations

Bioresour Technol. 2013 Apr:134:227-32. doi: 10.1016/j.biortech.2013.02.029. Epub 2013 Feb 21.

Abstract

The rendering product of Category 2 and 3 Animal By-Products is known as sterilized mass (SM) and it is mainly composed of fat and proteins, making it interesting substrate for anaerobic digestion. Batch and semi-continuous laboratory experiments were carried out to investigate the effect of SM addition in co-digestion with sewage sludge on methane production and possible process limitations. Results showed that SM addition in the feed mixture up to 5% (w/w), corresponding to 68.1% of the organic loading, increased methane production 5.7 times, without any indication of process inhibition. Further increase of SM addition at 7.5% (w/w) caused methane production decrease and volatile solids removal reduction, that was mainly related to remarkably increased free ammonia concentration in the digester of 596.5±68.6 gNH3 L(-1). Sterilized mass addition of 10% (w/w) caused intensive foaming, LCFA accumulation of 9172±701.2 mgCOD-LCFA g(-1) sample and termination of the experiment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abattoirs*
  • Animals
  • Batch Cell Culture Techniques
  • Biodegradation, Environmental
  • Bioreactors
  • Environmental Restoration and Remediation / methods*
  • Fatty Acids, Volatile / analysis
  • Methane / biosynthesis*
  • Organic Chemicals / isolation & purification
  • Oxygen / analysis
  • Sewage / analysis*
  • Solid Waste / analysis*
  • Sterilization*

Substances

  • Fatty Acids, Volatile
  • Organic Chemicals
  • Sewage
  • Solid Waste
  • Methane
  • Oxygen