The research progress, hotspots, challenges and outlooks of solid-phase denitrification process.

Area of Science:

• Environmental Science
• Environmental Engineering
• Microbiology

Background:

• Nitrogen pollution drives water eutrophication, posing significant ecological and health risks.
• Low-carbon wastewater presents challenges for conventional nitrogen removal methods.
• Solid-phase denitrification (SPD) is explored as a sustainable biological treatment.

Purpose of the Study:

• To review the progress, research hotspots, and challenges of the SPD process.
• To analyze the impact of various solid carbon sources (SCSs) on SPD performance.
• To identify strategies for strengthening SPD and addressing emerging contaminants.

Main Methods:

• Literature review focusing on SPD processes and different types of SCSs.
• Analysis of factors influencing denitrification performance, including SCS properties, pH, HRT, filling ratio, and temperature.
• Examination of SCS modification and coupled electrochemical technology as strengthening measures.

Main Results:

• Blended SCSs demonstrate higher application potential and have reached pilot-scale implementation compared to synthetic or natural SCSs.
• SCS characteristics influence microbial communities and gene enrichment, impacting denitrification efficiency.
• SPD performance is sensitive to operational parameters and SCS properties.

Conclusions:

• SPD is a viable process for low-carbon wastewater nitrogen removal, with blended SCSs showing significant promise.
• Strengthening SPD through SCS modification and integrated technologies is a key research direction.
• The SPD process faces new challenges from COVID-19-related wastewater contaminants, requiring further research and adaptation.