Feasibility of double nitrite supply through partial nitrification and partial denitrification driven by sludge...

Area of Science:

• Environmental microbiology
• Wastewater treatment technologies
• Biogeochemical cycles

Background:

• Stable nitrite supply is crucial for anammox processes in municipal wastewater treatment.
• Current methods for nitrite generation face challenges, limiting anammox application.

Purpose of the Study:

• To investigate sludge fermentation products as a dual-function solution for nitrite supply.
• To utilize these products for partial nitrification (PN) and partial denitrification (PD) to support anammox.

Main Methods:

• Employing sludge fermentation products as a carbon source and selective nitrification inhibitor.
• Optimizing carbon/nitrogen ratio and reaction time for partial denitrification.
• Assessing the impact of organic acids on ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB).

Main Results:

• Partial denitrification (PD) achieved >90% nitrite transformation within 15 days at a C/N ratio of 3.
• Organic acids (acetate, propionate) selectively inhibited NOB over AOB, facilitating PN.
• Combined anaerobic exposure and sludge fermentation products addition resulted in >80% nitrite accumulation.
• Significant tenfold increase in AOB abundance compared to NOB.

Conclusions:

• Sludge fermentation products offer a simplified and effective strategy for stable nitrite generation.
• This approach enhances the feasibility of anammox in municipal wastewater treatment.
• Demonstrates broad application potential for sustainable wastewater management.