The result revealed that the synthetic wastewater contained
sucrose (used for simulating organic compounds in the
wastewater) which is known as an easily-used organic carbon
[13]. Sucrose is a simple carbohydrate while phenol is an
aromatic hydrocarbon. Typically, microorganisms tended to
uptake simple structural substrate. This resulting in lower
phenol removal efficiency in the synthetic wastewater
compared to that of phenol solution presented in earlier
section. In the tests at high phenol concentration (100 mg/L),
phenol self-inhibition took place leading to very low phenol
removal.
3) MLSS monitoring
For MLSS monitoring, the initial MLSS from all tests
ranged from 840 to 1,340 mg/L. It was found that MLSS
increased along with the decreasing of COD for all tests
(Table III). The AS culture from the tests in this section
which was in the synthetic wastewater grew much more than
ones in the phenol solution in the previous section since
easily-uptaken carbon was supplied.