4. Conclusions
The findings of this study have shown that the sequential
anaerobic/aerobic system was efficient in the degradation of
diazo dye Reactive Black 5. In this experiment with partially
granulated sludge cultures and with glucose as co-substrate,
Reactive Black 5 dyestuff was almost decolorized under
anaerobic conditions. Up to 98% of the color of the azo
dyestuff was removed in the anaerobic stage. The released
intermediates were mineralized in the aerobic part of the
two stage system. It was observed that 85–95% of the remaining
COD was removed in the aerobic stage. No color
removal occurred aerobically. The COD removal efficiencies
were 40–60% at organic loading rates of 4–8 kgm−3
per day while the mean methane percentage was 70% in the
anaerobic UASB reactor.
About 100 mg l−1 Reactive Black 5 and 3000 mg l−1 of
glucose–COD containing wastewater was treated with a
maximum COD removal efficiency of 96% and the effluent
COD was reduced to 120 mg l−1 in the combined system.
The use of a granule containing UASB reactor has proven
the capability of resistance to shock organic loading. The
addition of UASB reactor systems prior to conventional activated
sludge systems, which are in use in many industries
in Turkey, will result with 90% color removal efficiency,
particularly in textile and dye industries.