To remove organic matter and nutrients (nitrogen and phosphorus),
many municipal wastewater treatment stations have been
designed as sequencing batch reactors (SBR) with a cycle format
(Cycle Activated Sludge System – CASS) in the last two decades.
The combination of aerobic and anoxic conditions enables nitrification
and denitrification in a single reactor, creating advantages
such as lower energy demand, smaller reactor volume and better
control of sludge bulking (Callado and Foresti, 2001; Lim et al.,
2011; Valdivia et al., 2007). However, most of the municipal wastewater
treatment plants in operation have faced difficulties with
sustainability, mainly because of the high costs of treatment (the
demand for energy and chemicals for the dewatering process)
and disposal (to a landfill or agricultural field) of the biological
sludge generated.