Using acclimated sludge, the removal of a copper-phthalocyanine dye (Reactive Turquoise Blue KN-G, RTB) from wastewater was studied under anaerobic and aerobic conditions to assess the fate of the RTB in wastewater treatment facilities. An immediately sharp reduction of the RTB concentration in solution was observed after the influent was fed into the reactor, which reflects rapid biosorption. Aerobic microorganisms were capable of utilizing RTB as the sole carbon and energy source for proliferation while anaerobic microorganisms were not, however, sufficient glucose as ancillary carbon source was essential for both systems to maintain long-term, stable and efficient performance. Glucose promoted the growth of biomass and microbial activity. Sufficient glucose prevented aerobic microorganisms decreasing activity due to high-concentration RTB. The cooperation of biosorption and biodegradation were considered to be the mechanisms for RTB removal from wastewater. (C) 2002 Elsevier Science Ltd. All rights reserved.