Title:
Side-stream Ammonia Stripping of Food Waste Anaerobic Digestion
Author(s):
Serna-Maza, A., Heaven, S., Banks, C.J.
Document(s):
Paper
Slide presentation
Abstract:
Three 35-L anaerobic digesters fed on source segregated food waste were coupled to side-stream ammonia stripping towers and operated semi-continuously over a period of 380 days, with results in terms of performance and stability compared to those of a control digester without stripping. The process used biogas as the stripping medium, with ammonia recovered by passing the gas phase through water and H2SO4 traps and the stripped liquor then returned to the digester. The stripping towers, which had a working volume equal to 6% of the digester, were operated under different conditions of temperature (55 °C, 70 °C, 85 °C) and pH (unadjusted and pH 10), and at varying retention times from 2 to 5 days. It was shown that the % removal of TAN in the towers depended on both temperature and pH, with increased removal at the higher temperatures and under alkaline conditions. To reduce digester TAN concentrations to a useful level a high temperature (= 70 oC) and a pH of around 10 were needed; under these conditions 48% of the TAN was removed over a 138-day period without any detrimental effects on digester performance. A secondary effect of the stripping process was an overall reduction in the digestate TKN compared to the control, and it was thought that this was a result of improved hydrolysis of the organic nitrogen-containing fraction of the waste and its subsequent removal as ammonia.
Keywords:
anaerobic digestion, side-stream stripping, food waste, ammonia removal
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.4.4
Pages:
707 - 713
ISBN:
978-88-89407-53-0
Paper DOI:
10.5071/21stEUBCE2013-2DO.4.4
Price:
FREE
