Production of volatile fatty acids from sewage organic matter by combined bioflocculation and alkaline fermentation.
This study explored the potential of volatile fatty acids (VFA) production from sewage by a combined high-loaded membrane bioreactor and sequencing batch fermenter. VFA production was optimized with respect to SRT and alkaline pH (pH 8-10). Application of pH shock to a value of 9 at the start of a sequencing batch cycle, followed by a pH uncontrolled phase for 7days, gave the highest VFA yield of 440mgVFA-COD/g VSS. This yield was much higher than at fermentation without pH control or at a constant pH between 8 and 10. The high yield in the pH 9 shocked system could be explained by (1) a reduction of methanogenic activity, or (2) a high degree of solids degradation or (3) an enhanced protein hydrolysis and fermentation. VFA production can be further optimized by fine-tuning pH level and longer operation, possibly allowing enrichment of alkalophilic and alkali-tolerant fermenting microorganisms.
Wetsus, European Centre of Excellence for Sustainable Water Technology, P.O. Box 113, 8900CC Leeuwarden, The Netherlands; Biobased Chemistry and Technology, Wageningen University, P.O. Box 17, 6700AA Wageningen, The Netherlands; Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700EV Wageningen, The Netherlands. Electronic address: rungnapha.khiewwijit@wetsus.nl.
Rungnapha
R
Khiewwijit
Wetsus, European Centre of Excellence for Sustainable Water Technology, P.O. Box 113, 8900CC Leeuwarden, The Netherlands; Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700EV Wageningen, The Netherlands.
Hardy
H
Temmink
Wetsus, European Centre of Excellence for Sustainable Water Technology, P.O. Box 113, 8900CC Leeuwarden, The Netherlands.
Alvaro
A
Labanda
Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700EV Wageningen, The Netherlands.
Huub
H
Rijnaarts
Wetsus, European Centre of Excellence for Sustainable Water Technology, P.O. Box 113, 8900CC Leeuwarden, The Netherlands; Biobased Chemistry and Technology, Wageningen University, P.O. Box 17, 6700AA Wageningen, The Netherlands.
Karel J
KJ
Keesman
D019149:Bioreactors; D005232:Fatty Acids, Volatile / Q000737:chemistry*; D005285:Fermentation; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D011506:Proteins / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*
D005232:Fatty Acids, Volatile; D011506:Proteins; D012722:Sewage
Alkaline pH; Anaerobic fermentation; Bioflocculation; Volatile fatty acids; Wastewater treatment