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Two-stage anaerobic digestion of energy crops: Methane production, nitrogen mineralisation and heavy metal mobilisation

Lehtomäki, Anni LU and Björnsson, Lovisa LU (2006) In Environmental Technology 27(2). p.209-218
Abstract
Energy crops (willow, sugar beet and grass silage) were digested ill pilot scale two-stage anaerobic digesters. The specific methane yields obtained were 0.16, 0.38 and 0.39 m(3) kg(-1) added volatile solids (VSadded) for willow, sugar beet and grass, respectively, corresponding to yearly gross energy yields of 15, 53 and 26 megawatt-hours (MWh) per hectare. With grass and sugar beets as substrate, 84-85% of the harvestable methane was obtained within 30 days. In pilot scale two-stage digestion of willow and sugar beet, 56 and 85,, of the laboratory scale methane yields were obtained, but digestion of grass in two-stage reactors yielded 5% more methane than digestion in laboratory scale completely mixed low solids systems, possibly due to... (More)
Energy crops (willow, sugar beet and grass silage) were digested ill pilot scale two-stage anaerobic digesters. The specific methane yields obtained were 0.16, 0.38 and 0.39 m(3) kg(-1) added volatile solids (VSadded) for willow, sugar beet and grass, respectively, corresponding to yearly gross energy yields of 15, 53 and 26 megawatt-hours (MWh) per hectare. With grass and sugar beets as substrate, 84-85% of the harvestable methane was obtained within 30 days. In pilot scale two-stage digestion of willow and sugar beet, 56 and 85,, of the laboratory scale methane yields were obtained, but digestion of grass in two-stage reactors yielded 5% more methane than digestion in laboratory scale completely mixed low solids systems, possibly due to the pH conditions favourable to hydrolysis in the two-stage system. In digestion of grass and sugar beet the liquid at the end of digestion was rich in ammonium nitrogen, and the nitrogen in the substrate was efficiently mineralised. The results show that heavy metal concentrations are not likely to limit the utilisation of residues from digestion of nonmetal accumulating crops. Efficient mobilisation of heavy metals during the acidic phase of digestion revealed the possibility of removing metals from leachate generated in two-stage anaerobic digestion of phytoextracting crops. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
nutrients, energy crops, two-stage process, biogas, methane
in
Environmental Technology
volume
27
issue
2
pages
209 - 218
publisher
Selper Ltd
external identifiers
  • wos:000235404600011
  • pmid:16506517
  • scopus:33644508949
ISSN
1479-487X
language
English
LU publication?
yes
id
76cca292-d3b0-4986-923a-97bd45be31de (old id 417512)
alternative location
http://www.ingentaconnect.com/content/selp/envt/2006/00000027/00000002/art00011
date added to LUP
2007-10-08 14:00:44
date last changed
2019-04-23 02:05:08
@article{76cca292-d3b0-4986-923a-97bd45be31de,
  abstract     = {Energy crops (willow, sugar beet and grass silage) were digested ill pilot scale two-stage anaerobic digesters. The specific methane yields obtained were 0.16, 0.38 and 0.39 m(3) kg(-1) added volatile solids (VSadded) for willow, sugar beet and grass, respectively, corresponding to yearly gross energy yields of 15, 53 and 26 megawatt-hours (MWh) per hectare. With grass and sugar beets as substrate, 84-85% of the harvestable methane was obtained within 30 days. In pilot scale two-stage digestion of willow and sugar beet, 56 and 85,, of the laboratory scale methane yields were obtained, but digestion of grass in two-stage reactors yielded 5% more methane than digestion in laboratory scale completely mixed low solids systems, possibly due to the pH conditions favourable to hydrolysis in the two-stage system. In digestion of grass and sugar beet the liquid at the end of digestion was rich in ammonium nitrogen, and the nitrogen in the substrate was efficiently mineralised. The results show that heavy metal concentrations are not likely to limit the utilisation of residues from digestion of nonmetal accumulating crops. Efficient mobilisation of heavy metals during the acidic phase of digestion revealed the possibility of removing metals from leachate generated in two-stage anaerobic digestion of phytoextracting crops.},
  author       = {Lehtomäki, Anni and Björnsson, Lovisa},
  issn         = {1479-487X},
  keyword      = {nutrients,energy crops,two-stage process,biogas,methane},
  language     = {eng},
  number       = {2},
  pages        = {209--218},
  publisher    = {Selper Ltd},
  series       = {Environmental Technology},
  title        = {Two-stage anaerobic digestion of energy crops: Methane production, nitrogen mineralisation and heavy metal mobilisation},
  volume       = {27},
  year         = {2006},
}