Uses and Dosing Ratio of Sodium Acetate in Wastewater Treatment Plants
In biological nitrogen removal processes, sodium acetate is one of the most commonly used external liquid carbon sources, especially suitable for wastewater treatment plants with insufficient influent carbon-to-nitrogen ratio (C/N) and high total nitrogen (TN) requirements.
1. Main Uses
1. Supplement denitrification carbon source: When biodegradable organics in influent are insufficient, sodium acetate provides rapidly available electron donors for denitrifying bacteria, accelerating the conversion of nitrate nitrogen (NO₃⁻-N) to nitrogen gas (N₂), thereby reducing effluent TN.
2. Enhance biological phosphorus removal: Polyphosphate-accumulating organisms use easily degradable organics such as sodium acetate for phosphorus release in anaerobic zones and excess phosphorus uptake in aerobic zones, assisting phosphorus removal efficiency.
3. Improve sludge activity: Appropriate dosing can stabilize microbial populations in biological systems and mitigate treatment instability caused by carbon source fluctuations.
4. Emergency and peak-load response: Used as a rapid-response carbon source during influent load shocks, low temperatures or high TN periods.
2. Dosing Ratio Reference
Sodium acetate dosing should be determined through bench-scale tests or operating data based on influent water quality, effluent TN target, sludge concentration, water temperature and dissolved oxygen. Engineering estimates are usually based on the COD required for denitrification relative to removed nitrate nitrogen, referring to relevant provisions in GB 50014-2021 "Outdoor Drainage Design Standard".
| Reference Item | Experience Range | Remarks |
|---|---|---|
| Denitrification C/N (COD/NO₃⁻-N) | Approx. 4 ~ 6 | COD required per unit nitrate nitrogen removed; actual value depends on design and operating conditions |
| Liquid sodium acetate dosing concentration | 30 ~ 100 mg/L (based on flow) | Common experience for municipal WWTPs; higher for high TN or industrial wastewater |
| Dosing point | Before anoxic tank / denitrification filter | Ensure adequate mixing with recycled nitrified liquor |
3. Selection Recommendation
Liquid sodium acetate product technical indicators can refer to HG/T 5959-2021 "Carbon Source Sodium Acetate for Biochemical Wastewater Treatment". Before actual dosing, it is recommended to conduct jar tests or pilot tests, and adjust dosage based on denitrification rate and effluent TN data to avoid increased operating costs or effluent COD rebound from overdosing.
Henan Fannuo New Material can assist wastewater treatment plants in calculating sodium acetate dosage based on actual water quality and process parameters, and provide liquid sodium acetate carbon source products.