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Management of hydrogen sulfide in anaerobic digestion of enzyme pretreated marine macro-algae

Haghighatafshar, Salar LU ; Kjerstadius, Hamse LU ; la Cour Jansen, Jes LU and Davidsson, Åsa LU (2012) In Vatten: tidskrift för vattenvård /Journal of Water Management and research 68(4). p.265-273
Abstract
Enzymatic pretreatment of algae by means of cellulose degrading enzyme was evaluated through lab-scale and pilot-scale experiments. The degradation efficiency of the enzyme depended on the initial physical quality of the algae. Lab-scale batch anaerobic digestion experiments showed comparatively low methane potential for the pretreated algae at both mesophilic and thermophilic temperatures. However, the raw algae (cut into small pieces) were found to be hardly hydrolysable. The methane potential of raw algae in thermophilic and mesophilic digestion was about 17 NmL/g VS and –36 NmL/g VS respectively. Presence of inhibitory agent(s) was obvious at both temperatures. Very fast growth of sulfate-reducing bacteria was noticed in the continuous... (More)
Enzymatic pretreatment of algae by means of cellulose degrading enzyme was evaluated through lab-scale and pilot-scale experiments. The degradation efficiency of the enzyme depended on the initial physical quality of the algae. Lab-scale batch anaerobic digestion experiments showed comparatively low methane potential for the pretreated algae at both mesophilic and thermophilic temperatures. However, the raw algae (cut into small pieces) were found to be hardly hydrolysable. The methane potential of raw algae in thermophilic and mesophilic digestion was about 17 NmL/g VS and –36 NmL/g VS respectively. Presence of inhibitory agent(s) was obvious at both temperatures. Very fast growth of sulfate-reducing bacteria was noticed in the continuous digestion, so that in less than 20 days, hydrogen sulfide concentrations over 10000 ppm were observed in both meso- and thermophilic reactors. Inhibition of methanogenesis in the thermophilic reactor occurred at unionized dissolved sulfide concentration of about 22 mg/L (10000 ppm in the biogas) while it was mainly non-SRB acetogens that were inhibited in the mesophilic reactor at unionized sulfide concentrations as high as 50 mg/L (17000 ppm in the biogas). This shows that probably thermophilic digestion is more prone to be inhibited at high sulfide concentrations. Micro-aeration was found to be more efficient in the thermophilic reactor while its effect on the mesophilic process was negligible. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Sulfate, Hydrogen sulfide, Anaerobic digestion, Enzymatic pretreatment, Marine macro-algae, Micro-aeration
in
Vatten: tidskrift för vattenvård /Journal of Water Management and research
volume
68
issue
4
pages
265 - 273
publisher
Föreningen Vatten
ISSN
0042-2886
language
English
LU publication?
yes
id
0086adf5-ac6d-41ee-8896-bc733b5ee75b (old id 3409140)
alternative location
http://www.tidskriftenvatten.se/wp-content/uploads/2017/04/48_article_4602.pdf
date added to LUP
2013-01-30 12:38:24
date last changed
2017-06-26 17:29:13
@article{0086adf5-ac6d-41ee-8896-bc733b5ee75b,
  abstract     = {Enzymatic pretreatment of algae by means of cellulose degrading enzyme was evaluated through lab-scale and pilot-scale experiments. The degradation efficiency of the enzyme depended on the initial physical quality of the algae. Lab-scale batch anaerobic digestion experiments showed comparatively low methane potential for the pretreated algae at both mesophilic and thermophilic temperatures. However, the raw algae (cut into small pieces) were found to be hardly hydrolysable. The methane potential of raw algae in thermophilic and mesophilic digestion was about 17 NmL/g VS and –36 NmL/g VS respectively. Presence of inhibitory agent(s) was obvious at both temperatures. Very fast growth of sulfate-reducing bacteria was noticed in the continuous digestion, so that in less than 20 days, hydrogen sulfide concentrations over 10000 ppm were observed in both meso- and thermophilic reactors. Inhibition of methanogenesis in the thermophilic reactor occurred at unionized dissolved sulfide concentration of about 22 mg/L (10000 ppm in the biogas) while it was mainly non-SRB acetogens that were inhibited in the mesophilic reactor at unionized sulfide concentrations as high as 50 mg/L (17000 ppm in the biogas). This shows that probably thermophilic digestion is more prone to be inhibited at high sulfide concentrations. Micro-aeration was found to be more efficient in the thermophilic reactor while its effect on the mesophilic process was negligible.},
  author       = {Haghighatafshar, Salar and Kjerstadius, Hamse and la Cour Jansen, Jes and Davidsson, Åsa},
  issn         = {0042-2886},
  keyword      = {Sulfate,Hydrogen sulfide,Anaerobic digestion,Enzymatic pretreatment,Marine macro-algae,Micro-aeration},
  language     = {eng},
  number       = {4},
  pages        = {265--273},
  publisher    = {Föreningen Vatten},
  series       = {Vatten: tidskrift för vattenvård /Journal of Water Management and research},
  title        = {Management of hydrogen sulfide in anaerobic digestion of enzyme pretreated marine macro-algae},
  volume       = {68},
  year         = {2012},
}