The application of aged refuse in nitrification biofilter: Process performance and characterization

Area of Science:

• Environmental Engineering
• Microbiology
• Wastewater Treatment

Background:

• Ammonium-rich wastewater treatment requires biofilters with high adsorption, biocompatibility, and low cost.
• Aged refuse presents a potential low-cost medium for biofiltration.

Purpose of the Study:

• To evaluate the performance of aged refuse as a biofilter for ammonium removal.
• To identify the primary ammonium conversion pathway in aged refuse biofilters.
• To assess the impact of operational conditions on nitrification.

Main Methods:

• Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET) analysis for physical characterization.
• X-ray Diffraction (XRD) for structural analysis.
• 16S rRNA gene sequencing for microbial community analysis.
• Parallel experiments with raw and inert refuse, and long-term biofilter operation.

Main Results:

• Initial ammonium adsorption reached 90.36% efficiency, with biodegradation becoming dominant over time.
• Aged refuse biofilters achieved 99% ammonium removal efficiency at a nitrogen loading rate of 1.28 kg/m³d.
• High nitrifier biodiversity ('Nitrosomonas', 'Nitrospira') was observed, though oxygen limitation impacted partial nitrification.

Conclusions:

• Biodegradation is the critical ammonium conversion pathway in aged refuse biofilters.
• Aged refuse demonstrates significant potential for efficient ammonium removal in wastewater treatment.
• Understanding microbial dynamics is key to optimizing biofilter performance and preventing nitrification failure.