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How applying dairy processing sludge in soils influences GHG emissions and associated mitigation measures

PhD defence, Monday 30 January 2023. Yihuai Hu.

Yihuai Hu

During his PhD studies, Yihuai Hu investigated the effects of dairy processing sludge (DPS) on greenhouse gas (GHG) emissions and crop yields in agricultural soils. The DPS is rich in phosphorus (P) as well as organic matter, while high organic matter leads to a high potential for GHG emissions. Thus, Yihuai carried out a series of experiments with transforming untreated DPS into different DPS-derived products (e.g., biochar), and compared their potentials for GHG emissions with untreated DPS, in order to find optimal products and conditions for recycling P from the waste for crop production without increasing GHG emissions.

Yihuai’s PhD project discovers that DPS-derived biochar has the potential for GHG mitigation and his new research findings contribute to an understanding of chemical and microbial processes that affect GHG emissions in soils applied with DPS and derived products, and provide guidance on the application of these new products as P-fertilizers and mitigation of GHG emissions.

The PhD study was completed at Department of Biological and Chemical Engineering, Faculty of Technical Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Monday 30 January 2023 at 9:30 am
Place: Building 1422, Richard Mortensen Stuen at the AU Conference Center, Aarhus University, Fredrik Nielsens Vej 2-4, 8000 Aarhus C
Title of PhD thesis: Nitrogen transformation and greenhouse gas emissions (GHG) from soils amended with dairy processing sludge (DPS) and derived fertilizer products

Contact information: Yihuai Hu, e-mail: hyh@bce.au.dk, tel.: +45 71 81 17 64

Members of the assessment committee:
Professor  David Chatwick, School of Natural Sciences, Bangor University, Wales

Associate Professor Sander Bruun, Department of Plant and Environmental Sciences, Copenhagen University, Denmark

Associate Professor Menglin Chen (chair), Department of Biological and Chemical Engineering, Aarhus University, Denmark

Main supervisor:
Professor Sven G. Sommer, Department of Biological and Chemical Engineering, Aarhus University, Denmark

Co-supervisor:
Associate Professor Sasha D. Hafner, Department of Biological and Chemical Engineering, Aarhus University, Denmark

Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Technical Sciences/GSTS,
Jens Baggesens Vej 53, building 5221, 8200 Aarhus N.

17427 / i43