Performance Evaluation of an Anaerobic-Aerobic SBR System for the Treatment of High Strength Industrial Wastewater

Abstract

A lab-scale anaerobic-aerobic SBR system was investigated for the treatment of high strength industrial wastewater. Anaerobic-aerobic SBR system was operated as a coupled system having 12 h HRT in each reactor and decoupled system having 48 h HRT in anaerobic reactor and 6 h in aerobic reactor. Results showed that coupled anaerobic- aerobic system, when used just for the combined organics removal is a suitable treatment but it is uneconomical due to reduction in biogas production. Increasing OLR in anaerobic SBR from 2- 6 kg COD/m3.d in coupled system caused instability of both reactors, and thus caused decline in biogas production from 11.0 to 10.7 L/d and % COD removal in anaerobic SBR from 59.0 to 43.8 % and combined from 98.5 to 94.5 %. Decoupling of reactors and using anaerobic reactor for organic removal and biogas production, and aerobic just for polishing purpose proved to be a cost effective and stable treatment with overall 98.6, 99.5 % organics and TKN removal, respectively and biogas production of 22.7 L/d was observed in decoupled system. Biogas production was increased up to 50 %, by increasing HRT in anaerobic reactor. Decoupled anaerobic-aerobic system also proved to be an economical and stable treatment, when used for the treatment of textile wastewater, containing reactive and basic dyes with overall organics, color and TKN removal of 99.6, 92.0 and 99.9 % respectively