|
Abstract:
|
Currently, most textile dye effluent is treated aerobically in an activated sludge
basin where aerobic microorganisms decompose waste components. However,
conventional aerobic biological treatment systems are not highly effective on reactive
dye color removal. The aerobic bacteria are not capable of breaking all of the strong
chemical bonds that were created for dye stability. Therefore, significant amounts of
color are released into lakes and streams.
Until recently, anaerobic biological treatment was used mainly in the brewing,
food processing, and pulp and paper industries because anaerobic bacteria are effective
on high oxygen demand waste effluent (Manahan, 1991). The textile industry has not
used conventional anaerobic treatments because textile waste is generally considered to
have low oxygen demands. Furthermore, anaerobic treatment usually requires longer
detention times for complete treatment in comparison to aerobic systems.
However, recent lab-scale research suggests that combined anaerobic/aerobic
treatment is a more effective and potentially less expensive method for color removal
than conventional aerobic treatment. Due to the low strength and low biodegradability
of textile dyes, methods of anaerobic treatment that sustain an adequate biomass
independent of the metabolism of dyes are suspected to be required. In this study,
sludge digestion and treatment of dyes for color removal via combined
anaerobic/aerobic processes were conducted concurrently. Findings indicated that
color removal is effective under anaerobic conditions; however, subsequent aerobic
treatment is required for organic removal.
|