关键词: activated sludge;COD;starch;recycling;hydrolytic-aerobic

Abstract: A new recycling hydrolytic-aerobic combined process was developed to treat the high
concentration used. At first, the hydrolytic degradation and aerobic degradation process
were examined in two batch reactors,respectively. In the stand-alone hydrolytic process,
starch in the wastewater almost disappeared after 11 h treatment,but CODCr remained as high
as 5803mg. L-1 after two days. In the aerobic process, the biodegradation rate of starch
was much slower during the first 11 h than that in the hydrolytic process, although the
CODCr removal efficiency reached 89.6% and more than 90% starch could be degraded after
37.5 h. To determine the interaction effects of the two processes, a series of hydrolytic-
aerobic combinations were examined in details. Hydrolytic process played an important role
in the whole recycle combination process as it could improve the biodegradability of the
high concentration starch wastewater. However, from the other experiments, the negative
effect of hydrolytic acidification was found in the hydrolytic-aerobic combination, which
suggested that the aerobic microorganisms needed time to adapt themselves to the acidic
environment. The effect of the degrading time, which was spent in the hydrolytic and
aerobic unit, and the number of circulations, with which the wastewater went through the
two units were investigated. It was found that a recycle combination of 6 h hydrolytic
process with 12 h aerobic process was highly effective and potentially economical, in which
the final removal efficiency of CODCr and efficiency of starch degradation reached 94.1%
and 98.8%, respectively.

Key words: activated sludge, COD, starch, recycling, hydrolytic-aerobic