Anaerobic co-digestion of the marine microalga Nannochloropsis salina with energy crops.
Anaerobic co-digestion of corn silage with the marine microalga Nannochloropsis salina was investigated under batch and semi-continuous conditions. Under batch conditions process stability and biogas yields significantly increased by microalgae addition. During semi-continuous long-term experiments anaerobic digestion was stable in corn silage mono- and co-digestion with the algal biomass for more than 200 days. At higher organic loading rates (4.7 kg volatile solids m(-3)d(-1)) inhibition and finally process failure occurred in corn silage mono-digestion, whereas acid and methane formation remained balanced in co-digestion. The positive influences in co-digestion can be attributed to an adjusted carbon to nitrogen ratio, enhanced alkalinity, essential trace elements and a balanced nutrient composition. The results suggest that N. salina biomass is a suitable feedstock for anaerobic co-digestion of energy crops, especially for regions with manure scarcity. Enhanced process stability may result in higher organic loading rates or lower digester volumes.
Ruhr-University Bochum, Institute of Thermo- and Fluid Dynamics, Universitaetsstr. 150, D-44801 Bochum, Germany. Electronic address: s.schwede@thermo.rub.de.
Sebastian
S
Schwede
Alexandra
A
Kowalczyk
Mandy
M
Gerber
Roland
R
Span
D000693:Anaerobiosis; D059001:Aquatic Organisms / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D056804:Biofuels / Q000032:analysis; D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D002254:Carbonates / Q000032:analysis; D018556:Crops, Agricultural / Q000378:metabolism*; D007700:Kinetics; D008697:Methane / Q000032:analysis; D058086:Microalgae / Q000378:metabolism*; D009930:Organic Chemicals / Q000032:analysis; D014131:Trace Elements / Q000032:analysis; D014835:Volatilization; D003313:Zea mays / Q000737:chemistry
D056804:Biofuels; D002254:Carbonates; D009930:Organic Chemicals; D014131:Trace Elements; D008697:Methane
Anaerobic digestion; Biogas; Corn silage; Microalgae; Nannochloropsis salina