Disintegrated Waste-Activated Sludge (NO 2 /FNA Method) as a Source of Carbon for Denitrification in the Mainstream of a WWTP.

The deficiency of readily biodegradable organic carbon can be a significant limitation to effective nitrogen removal during wastewater denitrification. Waste-activated sludge (WAS) is a source of carbon produced directly at wastewater treatment plants (WWTPs). Raw WAS has a large molecular weight and complex chemical structure molecules that are not easily available for microorganisms. In this study, easily biodegradable organic fractions were released using pH control and/or nitrites and nitric acid (NO₂/FNA). The obtained results indicated that WAS can be a sufficient carbon source for denitrification in WWTPs that are at risk of minor effluent violations. The implementation of WAS disintegration with the use of pH control and NO₂/FNA allowed for the denitrification of an additional 0.5 and 0.8 mgN-NO₃/L. WAS disintegration, besides being a source of carbon generation, reduces the volume of sludge and leads to the implementation of a closed-loop system. [ABSTRACT FROM AUTHOR]