Physical characterisation of the sludge produced in a sequencing batch biofilter granular reactor

Sequencing batch biofilter granular reactor (SBBGR) is a recently developed biological wastewater treatment technology characterised by a very low sludge production, among other numerous advantages. Even if costs for sludge treatment and disposal are mainly dependent on the amount of sludge produced, sludge properties, especially those linked to solid–liquid separation, play a key role as well. In fact, such properties deeply influence the type of treatments sludge has to undergo before disposal and the final achievable solids concentration, strongly affecting treatment and disposal costs. As sludge from SBBGR is a special mixture of biofilm and aerobic granules, no information is available so far on its treatability. This study addresses the characterisation of the sludge produced from SBBGR in terms of some physical properties (settling properties, dewaterability, rheology). The results show that such sludge is characterised by good settling and dewatering properties, adding a new advantage for the full-scale application of SBBGR technology.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (161 K)Download as PowerPoint slideHighlights► Some physical properties of SBBGR sludge (biofilm and granules) have been studied. ► SBBGR sludge demonstrates good settleability and dewaterability by centrifugation. ► Filtration under pressure is not a convenient treatment for SBBGR sludge. ► Easy sludge treatability and low sludge production represent important advantages.