Influence of sugar content of wastewater on the microbial characteristics of granular sludge developed at 20 degrees C in the anaerobic granular sludge bed reactor.
The influence of the sugar content of wastewater on changes in the characteristics of the retained sludge was investigated by using two lab-scale granular sludge bed reactors at 20 degrees C. Both reactors were inoculated with granular sludge grown at 20 degrees C and were fed with synthetic wastewater containing sucrose and volatile fatty acids (VFAs). On day 70, the sucrose content of the wastewater was changed to 90% (based on wastewater COD value) for the first reactor and 0% (VFA 90%) for the second. After this change in feed composition, the COD removal efficiency became about 91% for the sucrose-fed reactor and 95% for the VFA-fed reactor. The growth yield (Yg) of the sucrose-fed sludge increased more than that of the VFA-fed sludge. Consequently, deterioration of the settleability of the sucrose-fed sludge was observed. The sucrose-degrading activity of the retained sludge obtained from the sucrose-fed reactor increased significantly from 3.7 g COD g VSS(-1) day(-1) on day 62 to 36.8 g COD g VSS(-1) day(-1) on day 230, in accordance with the predominant growth of sugar-degrading bacteria--namely, Lactococcus, Clostridium and Chloroflexi--in the retained sludge. The excessive growth of these sugar-degrading bacteria in the retained sludge caused unstable process performance in the sucrose-fed reactor at 20 degrees C.
Water and Soil Environment Division, National Institute for Environmental Studies, Ibaraki, Japan.
Wilasinee
W
Yoochatchaval
Ikuo
I
Tsushima
Takashi
T
Yamaguchi
Nobuo
N
Araki
Haruhiko
H
Sumino
Akiyoshi
A
Ohashi
Hideki
H
Harada
Kazuaki
K
Syutsubo
D019149:Bioreactors / Q000382:microbiology*; D041862:Chloroflexi / Q000254:growth & development; D003013:Clostridium / Q000254:growth & development; D005232:Fatty Acids, Volatile / Q000737:chemistry; D017045:Lactococcus / Q000254:growth & development; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013395:Sucrose / Q000737:chemistry*; D013696:Temperature; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
D005232:Fatty Acids, Volatile; D012722:Sewage; D013395:Sucrose