GZXZEP Composite External Carbon Source is a high-COD liquid carbon source developed for biological denitrification and total-nitrogen removal in low-C/N wastewater. Its readily biodegradable organic components provide denitrifying microorganisms with an efficient electron donor, helping convert nitrate and nitrite into nitrogen gas while supporting stable anoxic treatment.
It is widely used in municipal wastewater denitrification, industrial low-C/N wastewater, anoxic-tank start-up, total-nitrogen polishing and automated external-carbon dosing systems.

• Direct liquid dosing without a make-down step. • High COD equivalent reduces storage and dosing volume. • Contains small organic acids, sugars, nutrients and buffering components. • Low-temperature grades available for winter operation.

• Municipal wastewater denitrification. • Industrial low-C/N wastewater. • Anoxic-tank process start-up. • Total-nitrogen polishing and automated carbon dosing.

• Model: NBC-70W. • Form: Viscous liquid. • pH: 5–8. • Density: 1.15±0.10 g/cm³. • COD equivalent: Approximately 700,000 mg/L for NBC-70W. • Catalog reference dose: Approximately 4.0 g product per g NO₃-N removed; confirm by mass balance and site commissioning.

1. Denitrifying microorganisms use the readily biodegradable carbon as an electron donor. 2. Nitrate and nitrite are converted to nitrogen gas in the anoxic zone. 3. Online nitrate or COD feedback can adjust the dosing rate and control excess COD.

• Packaging: 25 kg drum or 1,000 kg IBC. • Storage: Store sealed in a cool and shaded area. Prevent contamination and keep within the selected grade's approved temperature range. • Keep the container tightly closed after use.

• Customized formulation — The grade and dose are selected from influent nitrate, COD equivalent, water temperature and the cost per kilogram of nitrogen removed. This normally provides better treatment performance and overall cost efficiency than a one-formulation-for-all product. • In-house manufacturing — Competitive factory pricing, stable batch quality and fast lead times. • In-house laboratory — Rapid sample testing, formulation screening and continuous product improvement. • Engineering support — Professional engineers provide product selection, dosing, commissioning and after-sales troubleshooting support.