Application Principle of Sodium Acetate in Biological Denitrification

In wastewater treatment, nitrogen removal is a key step to meet discharge standards. Biological denitrification relies on denitrifying bacteria, and carbon source is the driving factor of this process. As a widely used external carbon source, sodium acetate plays an important role in biological denitrification.

1. Why Sodium Acetate as an External Carbon Source?

     √ Easily absorbed and metabolized by denitrifying bacteria;

     √ Safer and non-toxic compared to methanol;

     √ More stable than glucose, less risk of side reactions.

2. Mechanism of Sodium Acetate in Denitrification

During denitrification, nitrate (NO₃⁻-N) and nitrite (NO₂⁻-N) are reduced to nitrogen gas (N₂). Sodium acetate provides an efficient and readily available organic carbon source for this reaction.

3. Dosage Calculation of Sodium Acetate

The dosage depends on total nitrogen concentration and influent C/N ratio. Laboratory jar tests are recommended to determine the proper amount. Overdosing may increase COD, while underdosing leads to incomplete denitrification.

4. Comparison with Other Carbon Sources

     √ Sodium acetate vs methanol: safer and faster, but slightly higher cost;

     √ Sodium acetate vs glucose: more stable, less risk of sludge bulking;

     √ Sodium acetate vs acetic acid: better pH stability.

5. Application in Different Wastewater Types

     √ Municipal wastewater: improves denitrification under low C/N conditions;

     √ Food industry wastewater: provides stable carbon source for continuous denitrification;

     √ Industrial wastewater: suitable for chemical and pharmaceutical high-nitrogen wastewater.

6. FAQs

Q1: Does sodium acetate affect sludge properties?
A1: Proper dosage has no negative effect, but excessive dosage may cause sludge bulking.

Q2: Which is more economical, sodium acetate or methanol?
A2: Methanol is cheaper but has safety concerns; sodium acetate is safer and more efficient.