Effect of wastewater composition on methanogenic activity in an anaerobic reactor

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 CH ₄ 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.