The
domestic component is expected to provide some buffering in
terms of the characteristics of the combined flow and,
therefore, to enable an easier treatment of combined wastewater
compared to individual treatment of industrial effluents
on their own (Ng, 2006). The combined treatment of industrial
and domestic wastewater could represent an economically feasible
alternative in which the degradation of organic pollutants
is favoured by dilution and adaptation ability of the
activated sludge (Del Borghi et al., 2003).
However, due to the high amount of hydrophobic compounds
present in the textile component, the biological stage
of the centralized plant often suffers from sludge bulking and
foaming problems (Bortone et al., 1995; Mino, 1995). Furthermore,
a tertiary treatment stage is required to remove refractory
compounds and colour, with a consequent increase
in treatment scheme complexity and capital and operating
costs. This stage is often based on a coagulationeflocculation
treatment followed by ozonation