The combined activated sludge/contact aeration
(AS/CA) system proposed in this study combines suspended
and attached microbes to provide a longer food chain and more
complex biophase (Chen and Lo, 2003). This is to enhance the
removal of COD, O and G and true color. The system is also
expected to exhibit increased tolerance to spike loading, and
would require a smaller land area. The biodiversity of a
microbial consortium can be examined, through DGGE analysis
and polymerase chain reaction (PCR) techniques which can
amplify DNA material extracted from microbes (Fotiadis et al.,
2002). Each type of microbe has its own set of 16S-rDNA, and
by extracting a sample’s 16S-rDNA and matching its amount
and characteristics, to known microbes, the amount and types
of microbes present in a population can be determined (Liu et
al., 2002).
M
process costly. Although conventional biological treatment
processes have lower operating costs, they require larger land
space, and are poor in treating high O and G concentrations.
Their average O and G removal rate is just 20~30%. It has
been noted the maximum O&G concentration activated sludge
systems can efficiently decompose is 30mg/l