A simple small-scale syringe reactor system to investigate anaerobic wastewater treatment processes with granular sludge

Up-flow anaerobic sludge blanket (UASB) reactor technology was a very important invention in wastewater treatment and its operational concept can be described as a vertical up-flow pumping of wastewater through a layer of anaerobic sludge. It belongs to high-rate systems, which able to perform anaerobic reaction at reduced hydraulic retention time with low sludge production compared to traditional digesters. An important feature is the formation and retention of granules as bio-catalyzers of the process. However, investigation of UASB-reactors is complicated at laboratory-scale and operating many biological controls to draw statistically significant conclusions is challenging. A simple reactor system using off-the-shelf components was developed for the investigation of wastewater treatment processes with anaerobic granular sludge. As a proof of principle, we have investigated the effect of hydrogen addition (in situ biomethanation) on the process performance and microbial community structure by amplicon sequencing of the 16S rRNA and mcrA genes.