Experimental investigation of the performance of anaerobic membrane bioreactor with electrolytic regeneration (AMBER) for challenges and options in wastewater treatment.

Significant changes in wastewater services are necessary for achieving the sustainable development goals (SDGs), by utilizing resource recovery, recycle, and reuse in urban wastewater-treatment plants. Based on recent experiences, to improve the filtration behavior of a membrane bioreactor, a hybrid system including an upgraded anaerobic baffled reactor coupled with an electrolysis process and a nanocomposite-membrane was developed. The system, called an anaerobic membrane bioreactor with electrolytic regeneration (AMBER), is a bio-electrochemical process that is expected to be simultaneously efficient in both biogas augmentation and fouling mitigation. The goals were to enhance the stability and efficiency of the anaerobic membrane bioreactor. The integration of the electrolytic process with the ABR (EABR) using a pair of iron electrodes enhanced the removal of contaminants in the ABR while successfully maintained pH in the optimum range for anaerobic digestion (6.8 to 7.2). Then, the performance of AMBER in pollutant removal, including organic load, suspended solids, and microbial load, were investigated over 240 days. The results showed that configuration considerably enhanced permeate flux, as it reduced the deposition of extracellular polymeric substances (EPS) on the surface of the nanocomposite membrane, leading to a reduction in membrane fouling. EPS was extracted and quantified to compare the effect of biogas backwash on the function of the membrane reactor. After 7 d of operation with a daily biogas backwash, the flux reduction was approximately 13 % for the conventional combination of the anaerobic baffled reactor and the membrane bioreactor (AMBR), while it was limited to 4 % in AMBER. After cleaning by the biogas, EPS formation decreased 63 % in AMBER when compared to the AMBR. The results revealed that AMBER can be considered an environmentally competitive bioenergy technology for wastewater treatment with the purpose of water recovery and reuse, employing optimized operational conditions, application of antifouling membranes, and electrically-based strategies.

Characterization and Antibiofouling Performance Investigation of Hydrophobic Silver Nanocomposite Membranes: A Comparative Study.

Biofouling is one of the drawbacks restricting the industrial applications of membranes. In this study, different thicknesses of silver nanoparticles with proper adhesion were deposited on poly(vinylidenefluoride) (PVDF) and polyethersulfone (PES) surfaces by physical vapor deposition (PVD). The crystalline and structural properties of modified and pure membranes were investigated by carrying out X-ray diffraction (XRD) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Scanning electron microscope (SEM) and atomic force microscopy (AFM) analyses were employed to examine the surface morphology and the bacteria anti-adhesion property of the membranes. The morphology measurements confirmed that even though after silver grafting the surface became more hydrophobic, the homogeneity increased and the flux reduction decreased after coating. Moreover a comparison between PVDF and PES revealed that CFU (colony forming units) reduced 64.5% on PVDF surface and 31.1% on PES surface after modification. In conclusion, PVD improved the performance of the membrane antibiofouling, and it is more promising to be used for PVDF rather than PES.