Effect of Wastewater Composition on Methanogenic Activity in an Anaerobic Reactor

Abstract

In this study, effects of a chemical synthesis-based pharmaceutical wastewater on activity of acetoclastic methanogens within a lab-scale anaerobic completely stirred tank reactor (CSTR) were investigated. The CSTR was initially fed with glucose and loaded up to an organic loading rate of 6 kg COD m−3 d−1 at which 92% soluble COD removal efficiency was achieved. Acetoclastic methanogenic activity was found to be 336 mL CH4 gTVS−1 d−1. The CSTR was then, fed with several dilutions of preaerated wastewater with glucose at 10% wt v−1, 30% wt v−1, and 70% wt v−1 ratios and followed by 100% wt v−1 preaerated wastewater. In the latter, 71% soluble COD removal efficiency was obtained and a maximum acetoclastic methanogenic activity was 166 mL CH4 gTVS−1 d−1. Finally, raw wastewater diluted with preaerated wastewater was fed into the CSTR in increasing ratios of 10–60% wt v−1. Total failure of anaerobic reactor was observed at 60% wt v−1 raw wastewater fed. The study was, therefore, discontinued due to poor acetoclastic methanogenic activity of reactor sludge which was totally distorted.