Relationship between respiratory quotient, nitrification, and nitrous oxide emissions in a forced aerated composting process

Hirofumi Tsutsui; Taku Fujiwara; Daisuke Inoue; Ryusei Ito; Kazutsugu Matsukawa; Naoyuki Funamizu

doi:10.1016/j.wasman.2015.02.038

Relationship between respiratory quotient, nitrification, and nitrous oxide emissions in a forced aerated composting process

Waste Manag. 2015 Aug:42:10-6. doi: 10.1016/j.wasman.2015.02.038. Epub 2015 May 16.

Authors

Hirofumi Tsutsui¹, Taku Fujiwara², Daisuke Inoue³, Ryusei Ito⁴, Kazutsugu Matsukawa⁵, Naoyuki Funamizu⁴

Affiliations

¹ Research and Education Faculty, Natural Sciences Cluster, Agriculture Unit, Kochi University, B200 Monobe, Nankoku, Kochi, Japan; Japan Science and Technology Agency, CREST, Japan. Electronic address: jm-tsutsuih@kochi-u.ac.jp.
² Research and Education Faculty, Natural Sciences Cluster, Agriculture Unit, Kochi University, B200 Monobe, Nankoku, Kochi, Japan; Japan Science and Technology Agency, CREST, Japan.
³ Department of Health Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara-Minami, Kanagawa, Japan; Japan Science and Technology Agency, CREST, Japan.
⁴ Department of Environmental Engineering, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido, Japan; Japan Science and Technology Agency, CREST, Japan.
⁵ Research and Education Faculty, Multidisciplinary Science Cluster, Life and Environmental Medicine Science Unit, Kochi University, B200 Monobe, Nankoku, Kochi, Japan; Japan Science and Technology Agency, CREST, Japan.

PMID: 25987285
DOI: 10.1016/j.wasman.2015.02.038

Abstract

We assessed the relationship between respiratory quotient (RQ) and nitrification and nitrous oxide (N2O) 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 N2O was observed during the RQ decrease. Correlation between nitrification and N2O emission shows that the latter was triggered by nitrification. Mass balances demonstrated that the O2 consumption of nitrification (∼24.8mmol) was slightly higher than that of CO2 emission (∼20.0mmol), 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 N2O emission in forced aerated composting.

Keywords: Composting; Nitrification; Nitrous oxide; Respiratory quotient.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants / analysis*
Nitrification*
Nitrous Oxide / analysis*
Refuse Disposal / methods*
Soil / chemistry*

Substances

Air Pollutants
Soil
Nitrous Oxide