Effect of pH on nitrous oxide production and emissions from a partial nitritation reactor under oxygen-limited conditions. Issue 6 (June 2016)

• Record Type: Journal Article
• Authors: Lv, Yongtao; Ju, Kai; Wang, Lei; Chen, Xiaoqiang; Miao, Rui; Zhang, Xueling
• Is Part Of: Process biochemistry. Volume 51:Issue 6(2016:Jun.)
• Page Start: 765
• Page End: 771
• Publication Date: 2016-06
• Subjects: Partial nitritation -- Sequencing batch reactor -- Nitrous oxide -- pH -- Microelectrodes; Biochemical engineering -- Periodicals; Biotechnology -- Periodicals; Biochemistry -- periodicals; Biotechnology -- periodicals; Chemical Engineering -- periodicals; Génie biochimique -- Périodiques; Biotechnologie -- Périodiques; Biochemical engineering; Biotechnology; Periodicals; 660.63
• DOI: 10.1016/j.procbio.2016.02.017
• Languages: English
• ISSNs: 1359-5113

Abstract

Graphical abstract: Highlights: In a PN reactor, N2 O emissions decreased with the increase in initial pH. N2 O production inside sludge aggregates were quantified by using microelectrodes. A decrease in pH led to increased N2 O emissions from denitrification. Abstract: The effect of pH on nitrous oxide (N2 O) emissions from a laboratory-scale partial nitritation sequencing batch reactor under oxygen-limited conditions was investigated from both macro- and microscopic viewpoints. During the aeration period of a single cycle, N2 O emissions decreased when the initial pH increased from 7.5 to 8.5. By application of microelectrodes, N2 O production was observed inside entire sludge aggregates, and it increased with decreasing pH from 8.5 to 7.0. At pH 8.0 and 8.5, N2 O was mainly produced in the outer layer (<1000 μm) of sludge aggregates, where nitritation mainly occurred. At pH 7.0 and 7.5, N2 O production was mainly observed in the inner layer (>1000 μm), where the dissolved oxygen was almost depleted, revealing that the dominant pathway here was denitrification. Under oxygen-limited conditions, a decrease in pH led to increased N2 O emissions from denitrification pathway.