Effects of aeration modes and rates on nitrogen conversion and bacterial community in composting of dehydrated sludge and corn straw

Yuyun Wang; PengXiang Xu; Yue Wang; Jing Su; Zhi Xu; Zhengbo Jiang; Yuquan Wei; Sheng Hang; Xiaoyan Ding; Hao Zhang; Longli Zhang; Yongdi Liu; Ji Li

doi:10.3389/fmicb.2024.1372568

Effects of aeration modes and rates on nitrogen conversion and bacterial community in composting of dehydrated sludge and corn straw

Front Microbiol. 2024 Mar 12:15:1372568. doi: 10.3389/fmicb.2024.1372568. eCollection 2024.

Authors

Yuyun Wang^#¹, PengXiang Xu^#^{2

3

4}, Yue Wang^#^{2

3}, Jing Su⁵, Zhi Xu¹, Zhengbo Jiang^{2

3}, Yuquan Wei^{2

3}, Sheng Hang^{2

3}, Xiaoyan Ding^{2

3}, Hao Zhang⁶, Longli Zhang⁷, Yongdi Liu^{2

3}, Ji Li^{2

3}

Affiliations

¹ College of Resources and Environmental Science, Yunnan Agricultural University, Kunming, China.
² Beijing Key Laboratory of Biodiversity and Organic Farming, College of Resources and Environmental Science, China Agricultural University, Beijing, China.
³ Organic Recycling Institute (Suzhou) of China Agricultural University, Suzhou, China.
⁴ Academy of Agricultural Planning and Engineering, Ministry of Agriculture and Rural Affairs, Beijing, China.
⁵ Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, China.
⁶ Technical Centre for Soil, Agriculture and Rural Ecology and Environment, Ministry of Ecology and Environment, Beijing, China.
⁷ Beijing VOTO Biotech Co., Ltd., Beijing, China.

^# Contributed equally.

Abstract

Aeration is an important factor to regulate composting efficiency and nitrogen loss. This study is aimed to compare the effects of different aeration modes (continuous and intermittent) and aeration rate on nitrogen conversion and bacterial community in composting from dehydrated sludge and corn straw. Results showed that the intermittent aeration mode at same aeration volume was superior to the continuous aeration mode in terms of NH₃ emission reduction, nitrogen conversion and germination index (GI) improvement. Intermittent aeration mode with 1200 L/h (aeration 5 min, stop 15 min) [K5T15 (V1200)] and 300 L/h of continuous aeration helped to the conservation of nitrogen fractions and accelerate the composting process. However, it was most advantageous to use 150 L/h of continuous aeration to reduce NH₃ emission and ensure the effective composting process. The aeration mode K5T15 (V1200) showed the fastest temperature rise, the longer duration of thermophilic stage and the highest GI (95%) in composting. The cumulative NH₃ emission of intermittent aeration mode was higher than continuous aeration mode. The cumulative NH₃ emission of V300 was 23.1% lower than that of K5T15 (V1200). The dominant phyla in dehydrated sludge and corn straw composting were Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. The dominant phylum in the thermophilic stage was Firmicutes (49.39%~63.13%), and the dominant genus was Thermobifida (18.62%~30.16%). The relative abundance of Firmicutes was greater in the intermittent aeration mode (63.13%) than that in the continuous aeration mode (57.62%), and Pseudomonas was dominant in composting with lower aeration rate and the lowest NH₃ emission. This study suggested that adjustment to the aeration mode and rate could affect core bacteria to reduce the nitrogen loss and accelerate composting process.

Keywords: NH3 emission; aeration modes; aeration rates; composting; nitrogen fractions conversion.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the National Key Technology Research and Development Program of China (2022YFD1901504), the National Key Technology Research and Development Program of China (2023YFD1702200), National Natural Science Foundation of China (42307436, 32071552), the Independent Research Project of Science and Technology Innovation Base in Tibet Autonomous (XZ2022JR0007G), and the Independent Research Project of Science and Technology Innovation Base in Tibet Autonomous (XZ2022JR0007G).