Utilising biohydrogen to increase methane production, energy yields and process efficiency via two stage anaerobic digestion of grass.
Real time measurement of gas production and composition were used to examine the benefits of two stage anaerobic digestion (AD) over a single stage AD, using pelletized grass as a feedstock. Controlled, parallel digestion experiments were performed in order to directly compare a two stage digestion system producing hydrogen and methane, with a single stage system producing just methane. The results indicated that as well as producing additional energy in the form of hydrogen, two stage digestion also resulted in significant increases to methane production, overall energy yields, and digester stability (as indicated by bicarbonate alkalinity and volatile fatty acid removal). Two stage AD resulted in an increase in energy yields from 10.36 MJ kg(-1) VS to 11.74 MJ kg(-1) VS, an increase of 13.4%. Using a two stage system also permitted a much shorter hydraulic retention time of 12 days whilst maintaining process stability.
Sustainable Environment Research Centre, Faculty of Computing Engineering and Science, University of South Wales, Pontypridd CF37 1DL, United Kingdom. Electronic address: jmassane@glam.ac.uk.
Jaime
J
Massanet-Nicolau
Sustainable Environment Research Centre, Faculty of Computing Engineering and Science, University of South Wales, Pontypridd CF37 1DL, United Kingdom.
Richard
R
Dinsdale
Sustainable Environment Research Centre, Faculty of Computing Engineering and Science, University of South Wales, Pontypridd CF37 1DL, United Kingdom.
Alan
A
Guwy
Sustainable Environment Research Centre, Faculty of Computing Engineering and Science, University of South Wales, Pontypridd CF37 1DL, United Kingdom.
Gary
G
Shipley
D000468:Alkalies / Q000494:pharmacology; D000693:Anaerobiosis / Q000187:drug effects; D001639:Bicarbonates / Q000494:pharmacology; D056804:Biofuels; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D005232:Fatty Acids, Volatile / Q000096:biosynthesis; D006859:Hydrogen / Q000378:metabolism*; D008697:Methane / Q000096:biosynthesis*; D006109:Poaceae / Q000187:drug effects / Q000378:metabolism*; D013816:Thermodynamics
D000468:Alkalies; D001639:Bicarbonates; D056804:Biofuels; D005232:Fatty Acids, Volatile; D006859:Hydrogen; D008697:Methane
Anaerobic; Digestion; Hydrogen; Methane; Two-stage