Salinity-Driven Microbial Community Engineering for Safer Ultrafiltration Water Reuse

Area of Science:

• Environmental Science
• Microbiology
• Water Treatment Engineering

Background:

• Ultrafiltration is crucial for water reclamation but faces challenges with microbial regrowth and pathogen invasion.
• These issues compromise water biostability and biosafety in reclaimed water.

Purpose of the Study:

• To develop an ecological strategy using backwash as a microbiome engineering tool.
• To simultaneously address microbial regrowth and pathogen invasion in ultrafiltration systems.

Main Methods:

• Implementing high-salinity backwash (100 mM NaCl) during ultrafiltration.
• Analyzing microbial sources in permeate and pathogen inactivation in the biocake layer.
• Investigating microbiome composition and metabolic pathways using microbial ecology techniques.

Main Results:

• High-salinity backwash reduced permeate total cell counts by over 50%.
• Assimilable organic carbon removal increased by 32%, limiting microbial regrowth.
• Pathogen leakage was prevented, with 86.9% reduced pathogen accumulation due to accelerated inactivation.
• NaCl reshaped the biocake microbiome, enhancing cooperative functions and antimicrobial metabolite secretion.

Conclusions:

• High-salinity backwash effectively transforms ultrafiltration backwash into a microbiome engineering tool.
• This approach enhances both biostability and biosafety in ultrafiltration-based water reuse systems.
• Ecological engineering strategies offer a promising solution for secure water reclamation.