The prolonged startup period caused by slow and unstable biofilm formation remains a major barrier to large-scale application of membrane-aerated biofilm reactors (MABRs). This study developed a novel sodium alginate–assisted immobilization strategy to accelerate biofilm establishment and enhance nitrogen removal. A homogeneous mixture of sodium alginate and activated sludge was spray-coated onto plasma-treated PVDF hollow-fiber membranes, followed by CaCl₂ mist crosslinking to form a thin gel layer immobilizing active biomass. The coated MABR achieved 85 ± 5 % surface coverage within seven days—over twice that of the control—and complete ammonium oxidation (>90 %) in 10 days, reducing startup time by about 50 %. Digital microscopy and SEM revealed rapid transition from the synthetic alginate matrix to a self-sustained EPS network, while 16S rRNA sequencing confirmed enriched Nitrosomonas and Nitrospira with enhanced microbial diversity. The oxygen transfer rate initially decreased by 18 % after coating but recovered to 95 % of the original after partial scaffold dissolution, showing reversible mass-transfer adaptability. Mechanistically, the biodegradable Ca 2+ –alginate scaffold provided an initial attachment platform evolving into a stable stratified biofilm enabling simultaneous nitrification and denitrification. This study establishes a mechanistic and practical basis for biopolymer-assisted biofilm engineering toward rapid-startup, high-efficiency MABR systems.
Shanshan Xu,Yunbao Yan,Chendong Shuang,Qing Zhou,Rong Ji,Aimin Li
In this work, three biological ion exchange systems and one biological activated carbon (BAC) system were established by employing magnetic ion exchange resin (MIEX), non-magnetic resin (NIEX), polystyrenic resin (DIEX) and granular activated carbon as the biocarrier for advanced treatment of wastewater. Dissolved organic carbon (DOC) removal of four systems all stabilized at about 84% due to biodegradation. The start-up period of bio-MIEX (nearly 40 d) was greatly shorter than that of others (nearly 190 d). Ibuprofen removal was ascribed to adsorption in the initial stage, which subsequently changed to the effect of biodegradation. After the start-up period, ibuprofen removal was nearly 100% (bio-MIEX), 60% (bio-NIEX), 61% (bio-DIEX) and 89% (BAC). According to the surface observation, ATP and protein measurement and metagenomic analysis, the superior performance of bio-MIEX could be attributed to its highest biological activity resulted from the presence of Fe 3 O 4 rather than polymer matrix and surface roughness.
危险品化学品经营许可证（带存储）