Details

Title:

Effect of Ammonia Nitrogen on Thermophilic Anaerobic Digestion of Food Waste

Author(s):

Yirong, C., Banks, C.J., Heaven, S.

Document(s):

Abstract:

Two pairs of mesophilic anaerobic digesters were successfully acclimatised to thermophilic temperatures and operated on food wastes with low and high total Kjeldahl nitrogen contents (1.45 and 3.09% of dry weight, respectively), to assess the potential for ammonia inhibition. The digesters were monitored for stability and performance in terms of volatile fatty acid (VFA) profile, alkalinity, specific methane production and volatile solids (VS) destruction. The high­nitrogen digesters gave early signs of VFA accumulation but continued to show biogas production and stable pH before eventual failure at a total ammonia nitrogen (TAN) concentration > 5.0 g N l­1 , although the start of VFA accumulation had been noted at ~3 g N l­1. The low­nitrogen digesters showed no VFA accumulation and had a specific methane productivity of around 0.4 l CH4 g VS l­1 day­1 with 88% VS destruction. The low­nitrogen digesters ran under these conditions for 384 days before the TAN concentration was increased by urea addition. This resulted in VFA accumulation when the TAN concentration reached ~3 g N l­1 in one of the digesters, while stable operation without VFA accumulation was possible at a TAN concentration of 2 g N l­1 .

Keywords:

thermophilic, methane production, TAN, acclimatisation, ammonia inhibition

Topic:

R&D on Biomass Conversion Technologies for Heating, Electricity and Chemicals

Subtopic:

Anaerobic digestion for biogas production

Event:

21st European Biomass Conference and Exhibition

Session:

2DO.4.3

Pages:

701 - 706

ISBN:

978-88-89407-53-0

Paper DOI:

10.5071/21stEUBCE2013-2DO.4.3

Price:

FREE