TY - JOUR
T1 - Adaptation of semi-continuous anaerobic sludge digestion to humic acids
AU - Li, Ji
AU - Hao, Xiaodi
AU - van Loosdrecht, Mark C.M.
AU - Yu, Jinglun
AU - Liu, Ranbin
PY - 2019
Y1 - 2019
N2 - Anaerobic digestion (AD) is a technology for recovering chemical energy as methane from excess sludge/waste. Unfortunately, humic acids (HA) contained in excess sludge can have the effects of inhibiting the efficiency of energy conversion. Based on a batch experiment, the impact of HA on a semi-continuous AD process was sequentially investigated, with the impact on the associated enzymes and microorganisms being measured. The results of this semi-continuous experiment indicate that the inhibition of the microbial community increased with an increased HA:VSS ratio. Long-term cultivation did not result in the adaption of methane production to the presence of HA. Moreover, at HA:VSS = 20%, the strongest inhibition (74.3%) on energy conversion efficiency was observed in the semi-continuous experiment, which was two-fold higher than that recorded in the batch experiment. This is attributed to serious and irreversible inhibition of both acidogenic and methanogenic microorganisms, as well as the physical-chemical reactions between HA and the associated enzymes which, it was concluded, were the dominant mechanisms of inhibition in the batch experiment.
AB - Anaerobic digestion (AD) is a technology for recovering chemical energy as methane from excess sludge/waste. Unfortunately, humic acids (HA) contained in excess sludge can have the effects of inhibiting the efficiency of energy conversion. Based on a batch experiment, the impact of HA on a semi-continuous AD process was sequentially investigated, with the impact on the associated enzymes and microorganisms being measured. The results of this semi-continuous experiment indicate that the inhibition of the microbial community increased with an increased HA:VSS ratio. Long-term cultivation did not result in the adaption of methane production to the presence of HA. Moreover, at HA:VSS = 20%, the strongest inhibition (74.3%) on energy conversion efficiency was observed in the semi-continuous experiment, which was two-fold higher than that recorded in the batch experiment. This is attributed to serious and irreversible inhibition of both acidogenic and methanogenic microorganisms, as well as the physical-chemical reactions between HA and the associated enzymes which, it was concluded, were the dominant mechanisms of inhibition in the batch experiment.
KW - Anaerobic digestion (AD)
KW - Anaerobic microorganisms
KW - Energy conversion efficiency
KW - Humic acids (HA)
KW - Inhibition
KW - Semi-continuous experiment
UR - http://www.scopus.com/inward/record.url?scp=85067190281&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2019.06.016
DO - 10.1016/j.watres.2019.06.016
M3 - Article
SN - 0043-1354
VL - 161
SP - 329
EP - 334
JO - Water Research
JF - Water Research
ER -