Performance evaluation of integrated anaerobic and aerobic reactors for treatment of real textile wastewater

A hybrid anaerobic–aerobic treatability of real textile wastewater was investigated by using a lab-scale upflow anaerobic sludge blanket (UASB) coupled with a sequencing batch reactor (SBR). The performance of the integrated system was determined under various operational conditions. In phase I of the study, the UASB reactor was operated and optimized on real textile wastewater. The UASB was operated at a hydraulic retention time of 48 h in a semi-continuous mode with 12-h feeding and 12-h non-feeding cycle. Volatile fatty acid to alkalinity ratio was kept in the range of 0.42–0.72, while pH was strictly maintained between 6.8 and 7.2 under mesophilic conditions (35  $$^\circ$$ C). In phase II of the study, SBR was coupled with a UASB reactor and operated on real textile wastewater. The SBR was operated at an HRT of 6 h and solids retention time of 20 days. The integrated system was optimized with maximum removal efficiencies of 98% for chemical oxygen demand, 94% for color, 93% for total Kjeldahl nitrogen, and 89% for orthophosphate phosphorus. The results indicated that the integrated system is robust and flexible for the treatment of textile wastewater.