Anaerobic treatment of real textile wastewater with a fluidized bed reactor

Anaerobic treatability of a real cotton textile wastewater was investigated in a fluidized bed reactor (FBR) with pumice as the support material. The immobilized biomass or attached volatile solids level on the support material was 0.073 g VSS/g support material at the end of the 128-d start-up period. During the operation period, real cotton textile wastewater was fed to the anaerobic FBR both unsupplemented (in Stages 1 and 2) and supplemented (with synthetic municipal wastewater in Stage 3 and glucose in Stages 4–6). The effect of operational conditions such as organic loading rate (OLR), hydraulic retention time (HRT), influent glucose concentration as the co-substrate, etc. was investigated to achieve the maximum color removal efficiency in the reactor. Results indicated that anaerobic treatment of textile wastewater studied was possible with the supplementation of an external carbon source in the form of glucose (about 2 g/l). The corresponding maximum COD, BOD 5 and color removals were found to be around 82%, 94% and 59%, respectively, for HRT of around 24 h and OLR of 3 kg COD/m 3/d. Further increase in external carbon source added to real textile wastewater did not improve the color removal efficiency of the anaerobic FBR reactor.