High-Rate Nitrification Using Submerged Aerated Filter at Different Temperatures.

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Biological Wastewater Treatment

Background:

• Temperature significantly impacts biological nitrification processes.
• Biofilm reactors generally exhibit better low-temperature tolerance than suspended-growth systems.
• Fixed-bed reactors like submerged aerated filters (SAFs) offer higher nitrification rates than moving bed biofilm reactors (MBBRs) and are less prone to clogging.

Purpose of the Study:

• To investigate the effect of temperature on nitrification performance in a lab-scale nitrifying SAF.
• To determine the optimal temperature range for SAF nitrification.
• To compare SAF nitrification rates with other biofilm reactor types.

Main Methods:

• Operated a lab-scale nitrifying SAF at a volumetric ammonia loading rate (vALR) of approximately 1500 g N·m⁻³·d⁻¹.
• Tested performance across a temperature range of 9°C to 30°C.
• Developed a sigmoid function to model the temperature dependency of surface-specific ammonia oxidation rates (sAOR).

Main Results:

• Surface-specific ammonia and nitrite oxidation rates (sAOR and sNOR) remained stable between 15°C and 30°C.
• At 10°C, sAOR and sNOR decreased to approximately 1.19 and 0.92 g N·m⁻²·d⁻¹, respectively.
• Achieved surface-specific nitrification rates comparable to the highest reported for biological aerated filters (BAFs) and at least 2.5 times higher than MBBRs.

Conclusions:

• SAFs provide robust and efficient high-rate nitrification across a wide temperature range (15°C-30°C).
• The developed sigmoid model accurately predicts the temperature effect on sAOR in SAFs.
• SAFs are a promising technology for nitrification in tropical, subtropical, and temperate climates due to their high efficiency and stability.