Biofouling Formation and Bacterial Community Structure in Hybrid Moving Bed Biofilm Reactor-Membrane Bioreactors: Influence of Salinity Concentration

Abstract

Two pilot-scale hybrid moving bed biofilm reactor-membrane bioreactors were operated in parallel for the treatment of salinity-amended urban wastewater under 6 hours of hydraulic retention time and 2500 mg L−1 total solids concentration. Two salinity conditions were tested: the constant salinity of 6.5 mS cm−1 electric conductivity (3.6 g L−1 NaCl) and the tidal-like variable salinity with maximum 6.5 mS cm−1 electric conductivity. An investigation was developed on the biofouling produced on the ultrafiltration membrane surface evaluating its bacterial community structure and its potential function in the fouling processes. The results showed that biofouling was clearly affected by salinity scenarios in terms of α-diversity and β-diversity and bacterial community structure, which confirms lower bacterial diversity under variable salinity conditions with Rhodanobacter and Dyella as dominant phylotypes. Microorganisms identified as bio-mineral formers belonged to genera Bacillus, Citrobacter, and Brevibacterium. These findings will be of help for the prevention and control of biofouling in saline wastewater treatment systems.

Analysis of Microbial Community Dynamics during the Acclimatization Period of a Membrane Bioreactor Treating Table Olive Processing Wastewater

“…From the aforementioned results, it becomes evident that, upon introduction of TOPW, a drastic shift in the prokaryotes and eukaryotes present takes place; the organisms naturally present in TOPW and its specific chemical composition seem to exert a major pressure on the bio-community dynamics [50]. Such kind of shifts in wastewater treatment plants have already been described for other environmental factors, such as temperature [24] or salinity [51].…”

Treatment of High-Polyphenol-Content Waters Using Biotechnological Approaches: The Latest Update

“…In the 'classical' MBR design, the configuration can generally have a submerged or side-stream membrane using external recirculation. Currently, novel changes have been implemented in the classical MBR designs to adhere to more restrictive legislation [99][100][101]. There are several ways to remove the phenolic compounds contained in wastewater by diverse membrane bioreactor configurations [11], including the moving-bed bioreactor (MBBR) [100,102], the anaerobic-anoxic-oxic (A 2 O) membrane reactor [25], the two-phase partitioning membrane bioreactor [101], or the few novel designs with photocatalysis, using material coupled to the MBBR [103].…”

“…Mancuso et al [103] coupled a TiO 2 -based-photocatalyst that was doped with Fe and/or Cr with an MBBR. They emphasized the difficulties arising from OMWW treatment using only MBR technology due to the short membrane lifetimes, biofouling clogging, and high operational costs [99,104]. Therefore, they proposed a preliminary photocatalysis treatment driven by solar UV in presence of a TiO 2 semiconductor and metal elements to save energy and solve the limitations given by the energy required for the operation.…”

New Advances in Aerobic Granular Sludge Technology Using Continuous Flow Reactors: Engineering and Microbiological Aspects

“…In addition, AGS has a high biomass retention capacity, making it possible to treat large amounts of inflow in a smaller bioreactor relative to other technologies such as CAS because, as mentioned before, the surface in contact with raw water is greater [11]. Some research has reported a concentration of mixed liquor suspended solids (MLSS) close to 10 g L −1 [6], while in CAS technology this usually ranges from 2.5 to 4.5 g L −1 [30].…”