Can we shape microbial communities to enhance biological activated carbon filter performance?

Area of Science:

• Environmental microbiology
• Water treatment technologies
• Biogeochemistry

Background:

• Biofiltration efficacy relies on understanding microbial community structure-function linkages.
• Microbial assembly and interactions within biological activated carbon (BAC) filters remain largely unknown.
• Granular activated carbon (GAC) properties influence microbial community development and biofilter performance.

Purpose of the Study:

• To investigate the relationship between GAC properties, microbial community structure, and dissolved organic carbon (DOC) removal in BAC filters.
• To compare the performance of different GAC types (coal-based vs. wood-based) in BAC systems.
• To elucidate the assembly mechanisms (deterministic vs. stochastic) governing microbial communities in BAC filters.

Main Methods:

• Bench-scale BAC column experiments using various coal-based and wood-based GACs.
• Analysis of DOC removal efficiency.
• Characterization of microbial community structure using metaproteomics and co-occurrence network analysis.
• Evaluation of GAC pore size distribution and surface polarity.

Main Results:

• BAC-13, a coal-based GAC with specific micropore and micro-level macropore volumes, showed significantly higher DOC removal efficiency during steady-state operation compared to other GACs.
• Bacterial community assembly in BAC filters was primarily driven by deterministic factors, with GAC surface polarity being more influential than physical properties.
• Keystone species, such as Hyphomicrobium, played a significant role in metabolic functions, and their abundance was linked to specific pore size distributions (>100 μm).
• Microbial interactions within the BAC filter appeared cooperative rather than competitive.

Conclusions:

• Optimizing GAC pore size distribution, particularly micropores and micro-level macropores, is critical for enhancing BAC filter performance.
• Understanding deterministic assembly factors and identifying keystone species allows for targeted microbial community shaping to improve water treatment.
• Metaproteomics offers a valuable approach for accurately assessing the functional contributions of microbial species in engineered ecosystems.