Comparing liquid sodium acetate carbon sources on a COD-equivalent basis

Why do two carbon sources labeled 25% produce different denitrification costs?

A percentage may describe solute, anhydrous equivalent or commercial solution. Check available COD and the delivery measurement basis separately.

Separate carbon source composition from denitrification performance

Compare cost per unit of available COD first. Then test denitrification and residual effluent COD in actual wastewater at the same temperature and influent nitrate nitrogen as the current product.

A worked carbon-source cost comparison

At a delivered price of CNY 1,600 per tonne, suppose each kilogram of commercial product provides 0.4 kg COD by the same method. One tonne supplies 400 kg COD at CNY 4 per kilogram of COD. Actual denitrification cost also depends on utilization in the plant.

Does cloudiness in a liquid product establish expiry?

Check transit, temperature and the original retain. Test against the specification before deciding. Wastewater denitrification: Use actual wastewater and sludge to compare nitrogen removal and residual organics in the effluent. Liquid carbon-source metering: Use the pumped liquid’s density, flow and COA to calculate active material delivered per unit volume.

Checking Sodium acetate assay and COD equivalent

Sodium acetate assay (% by mass): Identify the hydrate or anhydrous reporting basis. COD equivalent (kg COD/kg product): Distinguish a theoretical conversion from a value measured using the specified method. Density (g/mL): For liquids only. State the temperature.

What to record

• Concentration basis
• Density
• Available COD
• Change in nitrate nitrogen
• Effluent COD

Technical references

• US EPA: evaluating external carbon sources for denitrification ↗

Products and processes