3.3.2. Comparison of denitrification parameters
Fig. 6 compares the special denitrification parameters such as
VDN,VCOD,PDN, and YH with three carbon sources. The VDN with
FLFWwas slightly smaller than that with sodium acetate but much
higher than that with glucose (Fig. 6a). However, regarding the
special value of VCOD, the greatest value was obtained with FLFW
but not sodium acetate, while that with glucose was still much
smaller (Fig. 6b). Higher VCOD often occurs in a wider variety of
microbial communities when incubating with a complex organic
mixture, because the COD consumption is related to the activity of
the whole microbial system but not merely denitrifying bacteria.
The patterns of microbial composition were found to be similar
when acetate, methanol, crude syrup and hydrolyzed starch were
used to stimulate the growth of different types of denitrifying
bacteria, while a more heterogeneous and metabolically versatile
microbial community appeared when crude syrup and hydrolyzed
starch were used as the carbon sources (Lee and Welander, 1996).
Due to the competition between different types of bacteria in uti-
lizing the FLFW carbon source, VDN became lower than that in the
case of using sodium acetate as a mono-component carbon source
solely for denitrificatio