Food waste fermentation for carbon source production and denitrification in sequencing batch reactors

Abstract

The disposal of food waste is a challenge for waste management while denitrification is often limited by the shortage of carbon source in wastewater treatment. Food waste has the potential to be used as carbon source for advanced nitrogen removal of secondary effluent. In this study, fermentation liquid production from food waste and the denitrification performance of simulated secondary effluent with fermentation liquid as carbon source in sequencing batch reactors, and the characteristics of the effluent after denitrification were investigated. The results indicated that the total chemical oxygen demand concentration reached 54.5 ± 4.7 g/L in the fermentation liquid with the ratio of total chemical oxygen demand/total nitrogen of 174.0 ± 24.0. Carbohydrate, lactate, volatile fatty acids were the main components. For the denitrification, the total nitrogen removal efficiencies of using fermentation liquid and sodium acetate as carbon source were 87.4 ± 7.2% and 95.0 ± 4.5%, respectively. There was no obvious difference in characteristics of the effluents (such as total chemical oxygen demand, dissolved organic carbon and specific UV absorbance at 254 nm) between the two carbon sources, confirming the feasibility of using fermentation liquid for advanced nitrogen removal.