Relationship between respiratory quotient, nitrification, and nitrous oxide emissions in a forced aerated composting process. (August 2015)

• Record Type: Journal Article
• Authors: Tsutsui, Hirofumi; Fujiwara, Taku; Inoue, Daisuke; Ito, Ryusei; Matsukawa, Kazutsugu; Funamizu, Naoyuki
• Is Part Of: Waste management. Volume 42(2015)
• Page Start: 10
• Page End: 16
• Publication Date: 2015-08
• Subjects: Composting -- Respiratory quotient -- Nitrification -- Nitrous oxide; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2015.02.038
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlights: RQ can be an indicator of N2 O emission in forced aerated composting process. Emission of N2 O with nitrification was observed with RQ decrease. Mass balances demonstrated the RQ decrease was caused by nitrification. Conversion ratio of oxidized ammonia and total N to N2 O were ∼2.7%. Abstract: We assessed the relationship between respiratory quotient (RQ) and nitrification and nitrous oxide (N2 O) emission in forced aerated composting using lab-scale reactors. Relatively high RQ values from degradation of readily degradable organics initially occurred. RQ then stabilized at slightly lower values, then decreased. Continuous emission of N2 O was observed during the RQ decrease. Correlation between nitrification and N2 O emission shows that the latter was triggered by nitrification. Mass balances demonstrated that the O2 consumption of nitrification (∼24.8 mmol) was slightly higher than that of CO2 emission (∼20.0 mmol), indicating that the RQ decrease was caused by the occurrence of nitrification. Results indicate that RQ is a useful index, which not only reflects the bioavailability of organics but also predicts the occurrence of nitrification and N2 O emission in forced aerated composting.