SBBGR results can be also compared with those of Lubello
and Gori (2004), who evaluated the efficiency of a membrane
bioreactor (MBR) as a treatment capable to substitute a fullscale
centralized WWTP (Baciacavallo, Prato, Italy) whose
characteristics are similar to the ones of Alto Seveso WWTP.
In fact, also the wastewater considered in that study has
mainly textile industry origin (80%), with a contribution of
domestic wastewater of about 20%. The treatment scheme is
based on preliminary treatments (screening, degritting), followed
by primary (coagulationeflocculation, primary
settling), secondary (biological oxidation, secondary settling)
and tertiary ones (clariflocculation, ozonation). Good performances
were achieved with MBR, leading to effluent COD
values around 60 mg/l independent of inlet loads, complete
nitrification (with no nitrite accumulation), good surfactant
removal and low permeate absorbance values, with a global
removal efficiency similar or higher than the one of the full
treatment chain of Baciacavallo WWTP. A monthly chemical
cleaning was, however, carried out in MBR whereas no
washing steps were required for SBBGR over 200 days of
operation. Moreover, the HRT was about 17e25 h in MBR
against 11 h in SBBGR