Treatment of textile wastewater is considered to be difficult by traditional systems. The present study is related to treatment of textile wastewater in an anaerobic reactor. The study showed the effectiveness of biological treatment of wastewater involving appropriate microorganism and suitable support media in a hybrid column, upflow anaerobic fixed bed (UAFB) reactor. COD and color were reduced to 84.80%, and 90% for textile wastewater. The reactor was operated at 1.038-8.21 g COD m(-3) d(-1) of loading and found that 81.58% COD and 86.22% color removal at the highest loading rate. At steady state under anaerobic condition, color was effectively removed. Biokinetic models were applied to data obtained from experimental studies in UAFB reactor. Treatment efficiencies of the reactor were investigated at different hydraulic retention times (9.6-23.76 h) and organic loading rates (1.038-8.21 g COD m(-3) d(-1)). Second-order and a Stover-Kincannon models were best fitted to the hybrid column reactor. The second-order substrate removal rate constant (k(2(S))) was found as 10.50 h(-1) for UAFB. Applying the modified Stover-Kincannon model to the UAFB reactor, the maximum removal rate constant (U-max) and saturation value constant (K-B) were found to be 31.69 and 45.37 g d(-1), respectively. (c) 2006 Elsevier B.V. All rights reserved.