The essential role of filling material in aerobic granular biomass generation in a periodic submerged biofilter

The paper reports the results of a laboratory-scale investigation aimed at evaluating the influence of the filling material of a Sequencing Submerged Biofilter Reactor (SSBR) on granular biomass generation. The results showed that aerobic granular biomass generation was obtained only in the reactor filled with kmt-k1 carrier, since the features of this filling media are such that they generate a bed characterised by rather uniform internal and external small-sized pore volumes able to retain the released biofilm particles. Finally, the aerobic granule formation improved the biomass retention efficiency and reduced the excess sludge production.