Bioreactors for wastewater to energy conversion: from pilot to full scale experiences

This chapter provides updated information and current state of the knowledge on bioreactors used for wastewater to energy conversion. Continuous stirred tank reactor (CSTR), anaerobic filter (AnF), up-flow anaerobic sludge blanket (UASB), and anaerobic membrane bioreactor (AnMBR) treating industrial wastewaters were reviewed. Among the focused reactors, the AnMBR offered many advantages (e.g., low HRT, high OLR), achieving high performances in terms of COD removal and biomethane yield (i.e., 99% and 0.55 m3 CH4 kg−1 CODremoved, respectively). However, an energy evaluation has suggested a higher energy recovery of UASB technology (i.e., 3.29 kWh kg−1 CODremoved) than those showed by CSTR, AnF, and AnMBR (i.e., 0.35, 2.21, and 2.40 kWh kg–1 CODremoved, respectively). The scale-up assessment has also revealed similar results between pilot and full-scale experience in Europe.