The effect of slime accumulated in a long-term operating UASB using crude glycerol to treat S-rich wastewater

An up-flow anaerobic sludge blanket (UASB) reactor targeting sulfate reduction was operated under a constant TOC/S-SO42− ratio of 1.5 ± 0.3 g C/g S for 639 days using crude glycerol as carbon source. A filamentous and fluffy flocculant material, namely slime-like substances (SLS), gradually accumulated in the bioreactor after cease methanogenic activity. The accumulation SLS followed by decrease removal efficiencies deterioration performance. Selected characteristics were investigated to explore causes its formation effect on UASB Results showed that fermentation processes taking place mainly accomplished bottom part reactor, concentration higher. caused flotation further led biomass washout, which decreased efficiencies. Batch activity tests performed with granular (GS), slime-covered (SCGS) there no difference between GS mechanism reduction. However, specific rate higher than SLS, while GS. different rates attributed relative abundances fermentative microorganisms found reducing bacteria (SRB)