Enhanced MTBE removal in fixed-bed bioreactor with iron-modified carriers: Biofilm structure and microbial community

• Published in: Journal of environmental chemical engineering 2025-02, Vol.13 (1), Article 114964
• Main Authors: Hua, Tingyu, Li, Shanshan, Hu, Jingli, Yan, Wei
• Format: Article
• Language: English
• Subjects: Biofilm; EPS; Iron modification; Microbial community; MTBE
• ISSN: 2213-3437
• DOI: 10.1016/j.jece.2024.114964

The residue of methyl tert-butyl butyl ether (MTBE) in groundwater poses a great threat to human health and needs to be addressed urgently. An efficient fixed-bed biofilm reactor was constructed by immobilizing MTBE-degrading bacteria Stenotrophomonas, Pseudoxanthomonas and Sphingobacterium on iron-modified activated carbon. The introduction of iron improved the specific surface area, zeta potential and hydrophilicity of the carrier, thus enhancing microbial adhesion. During reactor start-up, iron modification promoted the production of protein-dominated extracellular polymers, increased the biomass loaded on the carrier, and accelerated the formation of thicker (75.4 μm) and denser three-dimensional mesh biofilms. During operation, the iron-loaded reactor retained a thicker biofilm (157.9 μm) with greater stability and biological activity, which facilitated the removal of MTBE. Moreover, the iron-loaded biofilm system promoted the enriched growth of Stenotrophomonas with a higher percentage of MTBE-degrading bacteria (80 %), increased species richness and diversity under adverse conditions, thereby enhancing metabolic capacity and environmental tolerance. •Iron loading accelerated the formation of thicker and denser 3D mesh biofilms.•Iron modification promoted the secretion of protein-based extracellular polymers.•Iron loading increased biofilm biological activity, stability and tolerance.•Iron-modified carbon facilitated competitive growth of MTBE-degrading bacteria.•Iron-loaded biofilm system enhanced MTBE removal.