[Nitrite Accumulation Characteristics of Partial Denitrification in Different Sludge Sources Using Sodium Acetate as...

Area of Science:

• Environmental Science
• Environmental Engineering
• Microbiology

Background:

• Partial denitrification is crucial for efficient nitrogen removal in wastewater treatment.
• Understanding nitrite accumulation characteristics is key to optimizing this process.
• Different sludge sources may exhibit varying performance in partial denitrification.

Purpose of the Study:

• To investigate nitrite accumulation during partial denitrification using different sludge sources.
• To explore the impact of initial chemical oxygen demand (COD) and nitrate nitrogen (NO₃^--N) concentrations on partial denitrification.
• To compare the performance of two sequencing batch reactors (SBRs) inoculated with different sludges.

Main Methods:

• Two SBRs were inoculated with surplus sludge from different sources.
• Partial denitrification was achieved by controlling initial nitrate concentration and anoxic time.
• The study investigated carbon and nitrogen removal under varying initial COD and NO₃^--N concentrations.

Main Results:

• Partial denitrification was successfully established in both SBRs, achieving high nitrite accumulation rates (NAR).
• Increased initial COD concentration significantly shortened the time for maximum nitrite accumulation and improved the denitrification rate.
• The No.2 SBR, inoculated with sludge from a simultaneous nitrification and denitrifying phosphorus removal system, outperformed the No.1 SBR in nitrogen and carbon removal and partial denitrification.

Conclusions:

• Increased initial COD concentration is beneficial for nitrite accumulation during partial denitrification.
• The sludge source significantly impacts the efficiency of partial denitrification and nitrite accumulation.
• Optimized operational parameters, including COD and NO₃^--N levels, can enhance nitrogen removal via partial denitrification.