Chemical Engineering and Processing, Vol.131, 51-58, 2018
Assessment of anaerobic nanocomposite membrane bioreactor efficiency intensified by biogas backwash
Considering the biofouling issue in membrane bioreactors, an anaerobic nanocomposite membrane bioreactor was developed for an efficient wastewater treatment. Silver nanoparticles were deposited on the Poly(vinylidene-fluoride) and Polyethersulfone surfaces. An anaerobic baffled reactor was operated for 240 days at a hydraulic retention time of 30 h for the synthetic wastewater treatment, and then its effluent permeated through nanocomposite membranes in 7 days of continuous operations. Moreover, the membranes were scoured with the recirculation of the produced biogas of the anaerobic baffled reactor. Scanning electron microscopy, inhibitory zone and inductively coupled plasma mass-spectrometry were carried out. Extracellular polymeric substances were quantified to compare the effect of the backwash by the produced ABR biogas and the air, as control, on the membrane reactor performance. As results revealed, the flux reduction was more than 30% in unmodified membranes while it was limited to 12.5% in nanocomposite membranes. The results demonstrated that EPS formation decreased 51% and 91% in the pure PVDF and the nanocomposite PVDF and 57% and 81% in the pure PES and the nanocomposite PES, respectively, after cleaning by the biogas. All in all, the anaerobic nano composite membrane bioreactor can be considered as an appropriate wastewater treatment package for non potable reuse applications.