TY - CONF A1 - Kratz, S. A1 - Samman, N. A1 - Wilharm, E. A1 - Jabs, K. A1 - Anlauf, R. A1 - Vogel, Christian A1 - Bloem, E. T1 - Development of a standard substrate to facilitate the use of DGT for the assessment of P recycling fertilizers N2 - P recycling fertilizers are gaining increasing importance in our efforts to close nutrient cycles. An unsatisfactory performance of standard chemical extraction methods to assess the fertilizing effects of such products was reported. They demonstrated that DGT extractions of incubated soil/fertilizer mixtures were able to predict the fertilizing effects of the respective products more accurately. Since DGT works with soil/fertilizer mixtures, its interpretation is soil-dependent. Therefore, in order to facilitate its use as a tool to predict fertilizer performance, it needs to be standardized based on a standard substrate. This research aims to develop a standard substrate based on which evaluation categories for the DGT fertilizer extraction can be derived. The substrate composition should allow to vary the most important soil properties determining the plant availability of fertilizer P. It must also be reproducible at any time and any place. Substrate variants with varying proportions of quartz sand, a clay mineral and sphagnum peat were prepared and set to pH-levels 5.5 and 7 by addition of CaCO3. 7 variants were incubated with a set of test fertilizers (2 recycling fertilizers based on sewage sludge ash and 2 conventional mineral fertilizers) for 2 weeks. Substrate/fertilizer mixtures were then extracted with DGT and an ANOVA was performed to test if the DGT extraction was able to depict significant differences between fertilizers and substrate variants. An 8-week pot trial with ryegrass (3 cuts) was set up with the same substrate variants and test fertilizers. P uptake was determined to assess the fertilizing effect and correlated with the results of the DGT extractions. Statistically significant differences were found between DGT results for the various test fertilizers and substrate variants, indicating that DGT is able to differentiate between P solubility of fertilizers in relation to substrate quality. DGT results showed a strong relationship with P uptake, confirming that this method is suitable to predict the fertilizing effect of P fertilizers. Further optimization of substrate composition and tests with a wider variety of crops and fertilizer types are needed, before evaluation categories for DGT values can be derived. T2 - 6th Conference on Diffusive Gradients in Thin Films CY - Vienna, Austria DA - 17.09.2019 KW - Fertilzer KW - Phosphorus KW - Diffusive Gradients in thin films (DGT) PY - 2019 AN - OPUS4-49060 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vogel, Christian A1 - Adam, Christian A1 - Kugler, Stefan A1 - Herzel, Hannes T1 - Phosphorus recovery from waste streams for fertilizer production N2 - Phosphorus (P) plays an essential role in the global food security. However, the global P reservoirs have a statistic lifetime of about 385 years only. Due to the scarcity of P and the increasing world population an efficient and sustainable recycling management is required. A few biogenic waste materials are high in P contents such as sewage sludge and meat and bone meal. Thus, they are suitable for P recycling and fertilizer production. But besides the high P content sewage sludge is often highly contaminated with organic pollutants and toxic heavy metals which have to be eliminated before agricultural field application. In this presentation we show the potential of sewage sludge as secondary resource for fertilizers. This includes our developments in thermochemical processes for the production of novel P-fertilizers from recycled materials. Furthermore, for these novel P-fertilizers common extraction tests to determine the plant-available P are often unusable. Therefore, we successfully applied the Diffusive gradients in thin-films (DGT) techniques to analyse the plant-availability of P-fertilizers from recycled materials. T2 - Eingeladener Vortrag an der University of South Australia CY - Mawson Lakes, Australia DA - 22.11.2018 KW - Phosphorus recovery KW - Sewage sludge KW - Diffusive Gradients in thin films (DGT) PY - 2018 AN - OPUS4-46764 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogel, Christian A1 - Hoffmann, Marie A1 - Krüger, O. A1 - Murzin, V. A1 - Caliebe, W. A1 - Adam, Christian T1 - Chromium (VI) in phosphorus fertilizers determined with the diffusive gradients in thin-films (DGT) technique JF - Environmental Science and Pollution Research N2 - Phosphorus (P) fertilizers from secondary resources became increasingly important in the last years. However, these novel P-fertilizers can also contain toxic pollutants such as chromium in its hexavalent state (Cr(VI)). This hazardous form of chromium is therefore regulated with low limit values for agricultural products even though the correct determination of Cr(VI) in these fertilizers may be hampered by redox processes, leading to false results. Thus, we applied the novel diffusive gradients in thin-films (DGT) technique for Cr(VI) in fertilizers and compared the results with the standard wet chemical extraction method (German norm DIN EN 15192) and Cr K-edge X-ray Absorption near-edge structure (XANES) spectroscopy. We determined an overall good correlation between the wet chemical extraction and the DGT method. DGT was very sensitive and for most tested materials selective for the analysis of Cr(VI) in P-fertilizers. However, hardly soluble Cr(VI) compounds cannot be detected with the DGT method since only mobile Cr(VI) is analyzed. Furthermore, Cr K-edge XANES spectroscopy showed that the DGT binding layer also adsorbs small amounts of mobile Cr(III) so that Cr(VI) values are overestimated. Since certain types of the P fertilizers contain mobile Cr(III) or partly immobile Cr(VI), it is necessary to optimize the DGT binding layers to avoid aforementioned over- or underestimation. Furthermore, our investigations showed that the Cr K-edge XANES spectroscopy technique is unsuitable to determine small amounts of Cr(VI) in fertilizers (below approx. 1% of Cr(VI) in relation to total Cr). KW - Phosphorus fertilizer KW - Sewage sludge ash KW - Diffusive Gradients in thin films (DGT) KW - Chemical extraction KW - XANES spectroscopy PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509578 DO - https://doi.org/10.1007/s11356-020-08761-w SN - 0944-1344 VL - 27 SP - 24320 EP - 24328 PB - Springer AN - OPUS4-50957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -