PhD defence by Clara Kopp
Enhancement of phosphorus availability from biowaste ashes and chars
Recycling phosphorus (P) from waste materials through pyrolysis and incineration could reduce dependence on imports of rock phosphate and facilitate transport of P from regions with P surpluses. However, the P fertilizer effect of biochar and ash derived from these thermal treatments is limited due to a reduced P solubility. The objective of this PhD project was to assess the P availability from ashes and biochars derived from different P-rich wastes and to improve their P availability through different pre- treatment methods. Mainly chemical pre-treatments with sulfuric acid or sodium hydroxide were tested and the (pre-treated) materials were applied in growth experiments with different crops and soils. Differences in P fertilizer values between the materials and influence of factors such as soil pH were found and chemical pre-treatments that effectively increase the P fertilizer value of biochar and ash were identified, contributing to improved applicability and future use of biochar and ash as P fertilizers.
Assessment Committee
Senior Scientist Kari Ylivainio, Natural Resources Institute Finland Professor Bettina Eichler-Löbermann, Universität Rostock, Germany Professor Sander Bruun (Chair), PLEN, University of Copenhagen, Denmark
Supervisors
Associate Professor Dorette Müller-Stöver, PLEN, University of Copenhagen, Denmark Professor Lars Stoumann Jensen, PLEN, University of Copenhagen, Denmark
The defence is followed by a reception in meeting room R322/23 on 3rd floor
Everybody is welcome