Synthetic textile wastewater was biologically treated in aerobic and anaerobic
expanded bed reactors. The objectives of this study are to investigated the reduction of
COD (Chemical Oxygen demand), denitrification process, decolourisation process
and other related parameters. Experimental work was done using perspec columns
resctors which were innoculated with mixed culture. Granulated activated carbon was
used as a support medium. Samples were analysed for their outlet and inlet COD,
outlet and inlet nitrate, pH, temperature and biomass. It was observed that, a good
removal of COD, nitrate and colour were obtained. The results shows that aerobic
condition with dissolved oxygen less than 2.0 mg/L could reduce the accumulation of
toxid on the biofilm surface and could 'increase the efficiency of COD reduction as
well as denitrification and decolourisation process for a longer period. The results also
proved that simulatenous biodecolourisation and biodenitrification could a single
reactor for both system