Effects of various COD/NO ratios on NOx removal performance and microbial communities in a BTF−ABR integrated system. (April 2023)

• Record Type: Journal Article
• Authors: Wang, Yanling; Gong, Zerui; Xu, Xinyue; Chen, Pengfei; Zhao, Tianyu; Hu, Wenzhe; Xu, Meiying; Li, Jianjun; Huang, Shaobin
• Is Part Of: Chemosphere. Volume 321(2023)
• Publication Date: 2023-04
• Subjects: NOx removal -- COD/NO ratio -- Real-time PCR -- Microbial communities -- Microbial network; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2023.138121
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In this study, we investigated the removal performance of NOx and stability of the biotrickling filter−anaerobic baffled reactor (BTF−ABR) integrated system at various chemical oxygen demand (COD)/NO ratios (12.18, 6.71, and 4.63 in stages 1, 2, and 3, respectively) under 3.5% O2 and 50 ± 0.5 °C conditions for the first time. The results showed that the maximum elimination capacity of NOx was 4.46, 8.16, and 11.58 g/(m 3 ·h) in stages 1, 2, and 3, respectively. The minimum operating cost in terms of glucose was 4.79 g of glucose/g of NO. However, a COD/NO ratio of 12.18 resulted in a wastage of carbon sources, while a COD/NO ratio of 4.63 led to about 20 mg/m 3 N2 O emission at the end of the study. Highly bacteria diversity and positive co-occurrence networks at the COD/NO ratio of 6.71 were the main reasons for no intermediate accumulation or N2 O emission. Analysis of real-time polymerase chain reaction (PCR) indicated that nirS and norB were more sensitive to the changes in the COD/NO ratios than other denitrifying genes, and the denitrifiers with nirS filled more ecological niches as the NOx increased. Furthermore, although the decrease in COD/NO ratio significantly impacted the microbial community structure, the NOx RE was stabilized at over 90% because the micro-aerobic environment produced by ABR combined highly diverse microbes and functions in BTF, as well as the coordinated expression of denitrifying genes. Achieving efficient, stable, and low-cost denitrification is feasible in this BTF−ABR integrated system. Graphical abstract: Image 1 Highlights: The system achieved efficient and stable NOx removal at various COD/NO ratios. The BTF−ABR integrated system could reduce the denitration cost. BTF contained more functional groups and more complex co-occurrence networks than ABR. Denitrifiers with nirS filled more ecological niches as the NOx increased. Provided preliminary data to support a future industrial application for NOx removal.