TY - JOUR
T1 - Toward sustainable dairy waste utilization
T2 - Enhanced VFA and biogas synthesis via upcycling algal biomass cultured on waste effluent
AU - Smith, Simon A.
AU - Hughes, Eric
AU - Coats, Erik R.
AU - Brinkman, Cynthia K.
AU - Mcdonald, Armando G.
AU - Harper, Jeric R.
AU - Feris, Kevin
AU - Newby, Deborah
N1 - Publisher Copyright:
© 2015 Society of Chemical Industry.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - BACKGROUND: In 2012, 9.3 million head of dairy cows in the USA produced an estimated 20 million metric tons of manure solids, but little value was gained from this manure. There is a pressing need to enhance manure resource recovery efforts, as dairy manure has potentially significant environmental impacts. This study evaluated components of an integrated suite of biological processes designed to maximize resource recovery from dairy manure, in which algae grown on polyhydroxyalkanoate (PHA) production effluent (PHA-algae) were fermented and anaerobically digested to determine process impacts. RESULTS: A 10% PHA-algae supplement produced 11% more volatile fatty acids (VFA) during fermentation and 11% more methane during anaerobic digestion (AD) (vs. dairy manure); the PHA-algae biogas also contained a higher percentage (62.7 vs. 59.1%) of methane than manure biogas. Algal augmentation exhibited no negative effect on fermenter or AD operation. Quantitative polymerase chain reaction (PCR) showed that the ADs contained substantial populations of both acetoclastic and hydrogenotrophic methanogens, which, given the heterogeneous substrate, enhanced process stability. There were significant differences between PHA-algae batches, and large quantities of COD were released during algae freezing. CONCLUSION: PHA-algae yielded more VFA during fermentation, and a more methane-rich biogas following AD than dairy manure. A 10% PHA-algae supplement caused no process disturbance in normal manure flora.
AB - BACKGROUND: In 2012, 9.3 million head of dairy cows in the USA produced an estimated 20 million metric tons of manure solids, but little value was gained from this manure. There is a pressing need to enhance manure resource recovery efforts, as dairy manure has potentially significant environmental impacts. This study evaluated components of an integrated suite of biological processes designed to maximize resource recovery from dairy manure, in which algae grown on polyhydroxyalkanoate (PHA) production effluent (PHA-algae) were fermented and anaerobically digested to determine process impacts. RESULTS: A 10% PHA-algae supplement produced 11% more volatile fatty acids (VFA) during fermentation and 11% more methane during anaerobic digestion (AD) (vs. dairy manure); the PHA-algae biogas also contained a higher percentage (62.7 vs. 59.1%) of methane than manure biogas. Algal augmentation exhibited no negative effect on fermenter or AD operation. Quantitative polymerase chain reaction (PCR) showed that the ADs contained substantial populations of both acetoclastic and hydrogenotrophic methanogens, which, given the heterogeneous substrate, enhanced process stability. There were significant differences between PHA-algae batches, and large quantities of COD were released during algae freezing. CONCLUSION: PHA-algae yielded more VFA during fermentation, and a more methane-rich biogas following AD than dairy manure. A 10% PHA-algae supplement caused no process disturbance in normal manure flora.
KW - Algae
KW - Anaerobic digestion
KW - Fermentation
KW - Polyhydroxyalkanoate (PHA)
KW - Volatile solids
UR - http://www.scopus.com/inward/record.url?scp=84954398510&partnerID=8YFLogxK
U2 - 10.1002/jctb.4706
DO - 10.1002/jctb.4706
M3 - Article
AN - SCOPUS:84954398510
SN - 0268-2575
VL - 91
SP - 113
EP - 121
JO - Journal of Chemical Technology and Biotechnology
JF - Journal of Chemical Technology and Biotechnology
IS - 1
ER -