2.2. Preparation of raw domestic sewage
The practical wastewaters were obtained from Qingnianhu and
Weijinhe located in Tianjin, P.R. China. There is hardly any change
in the concentration of organic substrate (expressed by COD) in
raw domestic sewage. The water qualities of experimental sewage
are shown inTable 2showing that the organic substrates in raw
sewage were difficult to biodegrade