Performance of a tertiary submerged membrane bioreactor operated at supra-critical fluxes

Analysis of backwashing efficiency in dead-end hollow-fibre ultrafiltration of anaerobic suspensions

“…By operating under TMP set-point control mode, once an upper limit of TMP is reached (i.e. TMP set-point, TMP sp ), the permeate flux is immediately reversed, initiating the backwashing cycle (Villarroel et al 2013;Vera et al 2014). In several trials, nitrogen was supplied during backwashing through an extended aeration tube located inside the membrane module at a flow rate of 4.2 Nm 3 /h m 2 , managed by a mass flow controller (Bronkhorst®-EL-FLOW, The Netherlands).…”

“…This control system was developed in a previous lab-scale study (Villarroel et al 2013), which showed that membrane fouling can be significantly affected by the value of the transmembrane pressure set-point (TMPsp) selected for backwashing initiation. In addition, higher water productivity has been achieved in this controlled operation mode than in the conventional temporised filtration/backwashing mode on a pilot scale (Vera et al 2014). Nevertheless, the capability to re-disperse the cake layer detached from the membrane during backwashing in dead-end filtration is an important issue to be analysed.…”

Pilot plant study of a new rotating hollow fibre membrane module for improved performance of an anaerobic submerged MBR

“…6(a) and (b) show the filtration performance, expressed in terms of TMP i and duration of the filtration phase (t f ), respectively. TMP i , related to non-removable residual fouling by backwashing, shows the typical profile for systems where backwashing is initiated by TMP sp : an initial sharp increase during the first 25 h (from 19 to 23 kPa) followed by a lower gradual TMP i rise which finally stabilises after almost 135 h [47]. This residual fouling may be due to a progressive particle accumulation on the membrane surface, caused by the lengthening of the filtration phase during the first cycles ( Fig.…”

Fouling control strategy for submerged membrane bioreactor filtration processes using aeration airflow, backwash, and relaxation: a review

“…In addition, when varying the intensity of the air flow rate, an aeration-controlled strategy can also be implemented by the ON and OFF stage of the aeration supply. From an experiment conducted using a flat sheet-submerged MBR as related by Vera et al [9], they found that an aeration frequency of 10 s ON and 10 s OFF was the most optimum setting for their hollow fiber MBR, while no improvement was shown when the frequency was increased further. An aeration effect on fouling has been found to be more effective during an idle cleaning time, when compared to the permeation time.…”