The sludge in the reactor was observed the fifth day and the thirtieth
day using FISH by bacteria probe EUB338-CY3 and
ancient bacteria probe ARC915-FITC in this study, as illustrated
in Figs. 4 and 5. From the picture of the fifth day, fluorescence
intensity was too weak to prove that the number of
bacteria and ancient bacteria was small in the reaction zone I
and II. The relative abundance of bacteria in the reaction zone
I was 21.1% and the relative abundance of the ancient bacteria
was 23.5%. The relative abundance of bacteria and ancient bacteria
in the reaction zone II was 19.6% and 27.5%, respectively.
Meanwhile, it was found that relative abundance of bacteria plus
ancient bacteria was less than 50% in each reaction zone on the
fifth day. This phenomenon indicated that the microbe’s activity
was weak in the reactor because of the change in the environment.
The seed sludge needed some time to adapt the new environment
during the initial stage of the start-up operation.