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Pyrolyzed municipal sewage sludge ensured safe grain production while reduced C emissions in a paddy soil under rice and wheat rotation

  • Qianqian Shao
  • Yanyan Ju
  • Wenjie Guo
  • Xin Xia
  • Rongjun Bian
  • Lianqing Li
  • Wenjian Li
  • Xiaoyu Liu
  • Jufeng Zheng
  • Genxing PanEmail author
Research Article
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Abstract

Safe recycling of the growing amounts of municipal sewage sludge containing toxic metals had been critically challenged with the fast urbanization. In this study, we investigated soil amendment of municipal wastewater treatment (MSS) converted biochar for its recycling in agricultural soils. In a field experiment, unpyrolyzed (USS) and pyrolyzed municipal sewage sludge (PSS) was amended at 20 t ha−1 on dry base to a rice paddy before rice plantation, with a control without amendment. Grain yield and emission of non-CO2 potent greenhouse gases were examined as well as topsoil metal mobility and plant uptake determined throughout a rice-wheat rotation year. Compared to USS treatment, addition of PSS caused a significantly increased grain yield of rice by 35% but no change in grain yield of wheat following the rice season. No distinct difference was observed in grain concentration of major nutrients of N, P, and K between USS and PSS treatments. Compared to USS treatment, PSS treatment reduced CH4 emissions by 91.6% from soil and by 78.5% from ecosystem during rice-growing season. Whereas, PSS treatment led to a reduction of ecosystem N2O emissions by 70.8% relative to USS treatment during wheat-growing season. While both USS and PSS treatments slightly but insignificantly increased soil total content of heavy metals, PSS treatment reduced CaCl2-extractable Cd pool by 33~40% over USS treatment. Grain contents of Cd and Pb and Cd/Zn were markedly reduced under PSS over USS, without exceeding the Chinese state guideline limit. Carbon emission intensity was considerably (by over 20%) reduced for soil and ecosystem but unchanged for wheat soil, under PSS over USS. Thus, soil amendment of pyrolyzed sewage sludge could be a measure for climate smart soil and for safe grain production in rice agriculture. It deserves further study if repeated amendment could exert sustainable impacts on soil health and food security in the paddy.

Keywords

Sewage sludge Pyrolysis Biochar Greenhouse gas C emission intensity Heavy metals Rice paddy Biowaste treatment 
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Notes

Funding information

The work was partially funded by Ministry of Science and Technology of China under grant 201303095-11, by China Natural Science Foundation under a grant number of 41371298, and by UN GEF Green fund project of B4SS-2015. The authors are grateful for the XiaoQiang Farm Co. Ltd. for their assistance in field work.

Supplementary material

11356_2019_4417_MOESM1_ESM.docx (1.7 mb)
ESM 1 (DOCX 1737 kb)

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© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Institute of Resource, Ecosystem and Environment of AgricultureNanjing Agricultural UniversityNanjingChina
  2. 2.Jinhua Biomass Technology InstituteZhejiangChina
  3. 3.Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource UtilizationNanjingChina

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