TY - JOUR A1 - Herzel, Hannes A1 - Stemann, J. A1 - Simon, Sebastian A1 - Adam, Christian T1 - Comparison of thermochemical treatment of sewage sludge ash with sodium sulphate in laboratory-scale and pilot-scale experiments N2 - There is an ongoing debate on European scale concerning the criticality of phosphorus. In Switzerland and Germany, phosphorus recovery from phosphorus-rich waste streams will become obligatory. Sewage sludge ash is rich in phosphorus and may become an important secondary feedstock. Thermochemical treatment of sewage sludge ash with sodium sulphate under reducing conditions was shown to remove heavy metals from the solid product and produce the fully plant available crystalline phase CaNaPO4. Pilot-scale experiments in a rotary kiln were carried out at temperatures between 750 and 1000 °C and were compared to laboratory-scale experiments with crucibles. Process upscaling was successfully demonstrated but a series of differences were noticed: In comparison to laboratory-scale, solubility of phosphorus in samples from pilot-scale experiments was lower at all chosen treatment temperatures because of shorter retention time and incomplete decomposition of sodium sulphate. X-ray diffraction analysis revealed remaining phase fractions of whitlockite (Ca3-x(Mg,Fe)x(PO4)2) and sodium sulphate from the starting materials in products and thus indicated incomplete reaction. In contrast to the results of laboratory-scale experiments, the crystalline phase CaNaPO4 was clearly absent in the products from the rotary kiln but instead a Mg-bearing phase (Ca,Mg)NaPO4 was formed. Laboratory-scale experiments confirmed (Ca,Mg)NaPO4 is an intermediate phase between whitlockite and CaNaPO4. However, both crystalline phases are characterized by high plant availability. It was shown that heavy metal removal increased at higher temperatures whereas solubility and thus plant availability of phosphorus already reached its maxima at temperatures of 950 °C in pilot-scale and 875 °C in laboratory-scale experiments. KW - Crystalline phase identification KW - Heavy metal removal KW - Phosphorus availability KW - Process upscaling KW - Recovery KW - Rhenanite PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524084 DO - https://doi.org/10.1007/s13762-021-03252-y VL - 19 IS - 3 SP - 1997 EP - 2006 PB - Springer AN - OPUS4-52408 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weimann, Karin A1 - Adam, Christian A1 - Buchert, M. A1 - Sutter, J. T1 - Environmental Evaluation of Gypsum Plasterboard Recycling N2 - Gypsum is widely used in the construction sector and its worldwide consumption has been increasing for several decades. Depending on the life-time of the used gypsum products, an increase of gypsum in construction and demolition waste follows. Especially against the background of a circular economy, the recycling of waste gypsum is of growing importance. However, the use of recycled gypsum makes only sense if it is environmentally friendly. Therefore, an evaluation of the environmental impacts of an industrial-scale processing for the recycling of post-consumer gypsum waste was conducted. The evaluation was performed with an established life cycle assessment software. Original data provided by industry and complementary data from a database for life cycle assessments were used for the calculations. Two scenarios for recycled gypsum with different transportation distances were calculated. These results are compared with results of the environmental evaluation of gypsum derived from coal-fired power plants (FGD gypsum) and natural gypsum. The results show that utilization of recycled gypsum can be environmentally advantageous compared to the use of natural gypsum or FGD gypsum, especially in the impact categories land transformation and resource consumption (abiotic depletion potential). For most environmental impact categories the specific transportation distances have a strong influence. KW - Gypsum plasterboards KW - Gypsum waste KW - Recycled gypsum KW - Environmental evaluation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522321 DO - https://doi.org/10.3390/min11020101 SN - 2075-163X VL - 11 IS - 2 SP - 101 PB - MDPI CY - Basel, Schweiz AN - OPUS4-52232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Herzel, Hannes A1 - Aydin, Zeynep A1 - Adam, Christian T1 - Crystalline phase analysis and phosphorus availability after thermochemical treatment of sewage sludge ash with sodium and potassium sulfates for fertilizer production N2 - Phosphorus rich sewage sludge ash is a promising source to produce phosphorus recycling fertilizer. However, the low plant availability of phosphorus in these ashes makes a treatment necessary. A thermochemical treatment (800–1000 °C) with alkali additives transforms poorly plant available phosphorus phases to highly plant available calcium alkali Phosphates (Ca,Mg)(Na,K)PO4. In this study, we investigate the use of K2SO4 as additive to produce a phosphorus potassium fertilizer in laboratory-scale experiments (crucible). Pure K2SO4 is not suitable as high reaction temperatures are required due to the high melting point of K2SO4. To overcome this barrier, we carried out series of experiments with mixtures of K2SO4 and Na2SO4 resulting in a lower economically feasible reaction temperature (900–1000 °C). In this way, the produced phosphorus potassium fertilizers (8.4 wt.% K, 7.6 wt.% P) was highly plant available for phosphorus indicated by complete extractable phosphorus in neutral ammonium citrate solution. The added potassium is, in contrast to sodium, preferably incorporated into silicates instead of phosphorus phases. Thus, the highly extractable phase (Ca,Mg)(Na,K)PO4 in the thermochemical products contain less potassium than expected. This preferred incorporation is confirmed by a pilot-scale trial (rotary kiln) and thermodynamic calculation. KW - Phosphorus recovery KW - Recycling fertilizer KW - Calcium alkali phosphate KW - Silicate PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536276 DO - https://doi.org/10.1007/s10163-021-01288-3 SN - 1611-8227 IS - 23 SP - 2242 EP - 2254 PB - Springer AN - OPUS4-53627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Raniro, H.R. A1 - Soares, T.de M. A1 - Adam, Christian A1 - Pavinato, P.S. T1 - Waste-derived fertilizers can increase phosphorus uptake by sugarcane and availability in a tropical soil N2 - The use of highly water-soluble phosphorus (P) fertilizers can lead to P fixation in the soil, reducing fertilization efficiency. Waste-derived, low water-solubility sources can potentially increase sugarcane’s P uptake compared to triple superphosphate by reducing adsorption to the soil. Aims:We aimed to test struvite, hazenite, and AshDec® for their agronomic potential as recycled fertilizers for sugarcane production in a typical tropical soil.We hypothesize that these sources can reduce P fixation in the soil, increasing its availability and sugarcane’s absorption. Methods: In a greenhouse pot experiment, two consecutive sugarcane cycles, 90 days each, were conducted in a Ferralsol. The recovered sources struvite, hazenite, AshDec®, and the conventional triple superphosphate were mixed in the soil in three P doses (30, 60, and 90 mg kg–1), aside a control (nil-P). At both harvests, sugarcane number of sprouts, plant height, stem diameter, dry mass yield, shoot phosphorus, and soil P fractionation were investigated. Results: At 90 days, struvite and hazenite performed better for dry mass yield (70.7 and 68.3 g pot–1, respectively) than AshDec® and triple superphosphate (59.8 and 57.4 g pot–1, respectively) and for shoot P, with 98.1, 91.6, 75.6, and 66.3 mg pot–1, respectively. At 180 days, struvite outperformed all treatments for dry mass yield (95.3 g pot–1) and AshDec® (75.5 mg pot–1) for shoot P. Struvite was 38% and hazenite 21% more efficient than triple superphosphate in P uptake, while AshDec® was 6% less efficient. Soil had higher labile P under struvite, hazenite, and AshDec® than triple superphosphate by the end of the first cycle, while only the later increased nonlabile P by the end of the experiment (180 days). Conclusions:Waste-derived P sources were more efficient in supplying P for sugarcane and delivering labile P in 180 days than triple superphosphate. KW - AshDec KW - Hazenite KW - P-efficiency KW - Recycled sources KW - Struvite PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544216 DO - https://doi.org/10.1002/jpln.202100410 SN - 1436-8730 SP - 1 EP - 12 PB - Wiley-VCH GmbH AN - OPUS4-54421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schraut, Katharina A1 - Kargl, F. A1 - Adam, Christian A1 - Ivashko, O. T1 - In situ synchrotron XRD measurements during solidification of a melt in the CaO–SiO2 system using an aerodynamic levitation system N2 - Phase formation and evolution was investigated in the CaO–SiO2 system in the range of 70–80 mol% CaO. The samples were container-less processed in an aerodynamic levitation system and crystallization was followed in situ by synchrotron x-ray diffraction at the beamline P21.1 at the German electron synchrotron (DESY). Modification changes of di- and tricalcium silicate were observed and occurred at lower temperatures than under equilibrium conditions. Despite deep sample undercooling, no metastable phase formation was observed within the measurement timescale of 1 s. For the given cooling rates ranging from 300 K s−1 to about 1 K s−1, no decomposition of tricalcium silicate was observed. No differences in phase evolution were observed between reducing and oxidizing conditions imposed by the levitation gas (Ar and Ar + O2). We demonstrate that this setup has great potential to follow crystallization in refractory oxide liquids in situ. For sub-second primary phase formation faster detection and for polymorph detection adjustments in resolution have to be implemented. KW - Aerodynamic levitation KW - Calcium silicate KW - Phase formation KW - Oxide melts KW - In situ synchrotron x-ray diffraction PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526952 DO - https://doi.org/10.1088/1361-648X/abf7e1 VL - 33 IS - 26 SP - 264003 (12pp) PB - IOP Publishing AN - OPUS4-52695 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sichler, Theresa Constanze A1 - Adam, Christian A1 - Barjenbruch, M. A1 - Montag, D. A1 - Mauch, Tatjana A1 - Sommerfeld, Thomas A1 - Ehm, J.H. T1 - Variation of the element composition of municipal sewage sludges in the context of new regulations on phosphorus recovery in Germany N2 - Phosphorus (P) recovery is obligatory for all sewage sludges with more than 20 g P/kg dry matter (DM) from 2029 in Germany. Nine wastewater treatment plants (WWTPs) were chosen to investigate variations of phosphorus contents and other parameters in sewage sludge over the year. Monthly sewage sludge samples from each WWTP were analyzed for phosphorus and other matrix elements (C, N, H, Ca, Fe, Al, etc.), for several trace elements (As, Cr, Mo, Ni, Pb, Sn) and loss of ignition. Among the nine WWTPs, there are four which have phosphorus contents both above and below the recovery limit of 20 g/kg DM along the year. Considering the average phosphorus content over the year, only one of them is below the limit. Compared to other matrix elements and parameters, phosphorus fuctuations are low with an average of 7% over all nine WWTPs. In total, only hydrogen and carbon are more constant in the sludge. In several WWTPs with chemical phosphorus elimination, phosphorus fuctuations showed similar courses like iron and/or aluminum. WWTPs with chamber flter presses rather showed dilution efects of calcium dosage. As result of this study, monthly phosphorus measurement is highly recommended to determine whether a WWTP is below the 20 g/kg DM limit. KW - Sewage sludge KW - Phosphorus recovery KW - Wastewater KW - Phosphorus elimination PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557499 DO - https://doi.org/10.1186/s12302-022-00658-4 SN - 2190-4707 VL - 34 IS - 1 SP - 1 EP - 12 PB - Springer Nature CY - Berlin AN - OPUS4-55749 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sichler, Theresa Constanze A1 - Adam, Christian A1 - Becker, Roland A1 - Sauer, Andreas A1 - Ostermann, Markus A1 - Barjenbruch, M. T1 - Phosphorus determination in sewage sludge: comparison of different aqua regia digestion methods and ICP-OES, ICP-MS and photometric determination N2 - Phosphorus recycling from sewage sludge will be obligatory in Germany from 2029. Phosphorus content determination in sewage sludge is crucial to assess the prescribed recycling rates. Currently, German law regards sample preparation using aqua regia digestion in a microwave or under reflux conditions as well as instrumental phosphorus determination by ICP-OES, ICP-MS, or photometric determination with ammonium molybdate as equivalent. However, it is questionable whether these methods are indeed equivalent regarding phosphorus quantification in sludges near the limit of 20 g/kg for mandatory recycling. To answer this question, 15 sewage sludges of 11 different wastewater treatment plants were investigated with all permitted method (digestion and measurement) combinations. Moreover, one sewage sludge was also examined in an interlaboratory comparison (ILC) with 28 participants. This study shows that the above-mentioned methods differ in some cases significantly but across all method combinations and sludges, phosphorus recovery was between 80 and 121% after normalization to the grand mean (average of 15 sludges between 85 and 111%). The ILC and the examination of 15 sludges produced largely similar results. There is a tendency to higher phosphorus recovery after microwave digestion compared to reflux digestion and ICP-OES measurements determine higher phosphorus contents than ICP-MS and photometric phosphorus determination. As a result, the authors recommend ICP-OES determination of phosphorus in sewage sludge after microwave digestion. KW - Sewage sludge KW - ICP-OES KW - Phosphous recovery KW - ICP-MS KW - Photometric P determination KW - Interlaboratory comparison PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558869 DO - https://doi.org/10.1186/s12302-022-00677-1 VL - 34 IS - 99 SP - 1 EP - 14 PB - Springer AN - OPUS4-55886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dombinov, V. A1 - Herzel, Hannes A1 - Meiller, M. A1 - Müller, F. A1 - Willbold, S. A1 - Zang, J. W. A1 - da Fonseca-Zang, W. A. A1 - Adam, Christian A1 - Klose, H. A1 - Poorter, H. A1 - Jablonowski, N. D. A1 - Schrey, S. D. T1 - Sugarcane bagasse ash as fertilizer for soybeans: Effects of added residues on ash composition, mineralogy, phosphorus extractability and plant availability N2 - Sugarcane bagasse is commonly combusted to generate energy. Unfortunately, recycling strategies rarely consider the resulting ash as a potential fertilizer. To evaluate this recycling strategy for a sustainable circular economy, we characterized bagasse ash as a fertilizer and measured the effects of co-gasification and co-combustion of bagasse with either chicken manure or sewage sludge: on the phosphorus (P) mass fraction, P-extractability, and mineral P phases. Furthermore, we investigated the ashes as fertilizer for soybeans under greenhouse conditions. All methods in combination are reliable indicators helping to assess and predict P availability from ashes to soybeans. The fertilizer efficiency of pure bagasse ash increased with the ash amount supplied to the substrate. Nevertheless, it was not as effective as fertilization with triple-superphosphate and K2SO4, which we attributed to lower P availability. Co-gasification and co-combustion increased the P mass fraction in all bagasse-based ashes, but its extractability and availability to soybeans increased only when co-processed with chicken manure, because it enabled the formation of readily available Ca-alkali phosphates. Therefore, we recommend co-combusting biomass with alkali-rich residues to increase the availability of P from the ash to plants. KW - Combustion and gasification KW - Phosphate extractability and availability KW - X-ray diffraction (XRD) PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567632 DO - https://doi.org/10.3389/fpls.2022.1041924 SN - 1664-462X VL - 13 SP - 1 EP - 13 PB - Frontiers Media CY - Lausanne AN - OPUS4-56763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jovičević-Klug, Matic A1 - Souza Filho, Isnaldi R. A1 - Springer, Hauke A1 - Adam, Christian A1 - Raabe, Dierk T1 - Green steel from red mud through climate-neutral hydrogen plasma reduction N2 - AbstractRed mud is the waste of bauxite refinement into alumina, the feedstock for aluminium production1. With about 180 million tonnes produced per year1, red mud has amassed to one of the largest environmentally hazardous waste products, with the staggering amount of 4 billion tonnes accumulated on a global scale1. Here we present how this red mud can be turned into valuable and sustainable feedstock for ironmaking using fossil-free hydrogen-plasma-based reduction, thus mitigating a part of the steel-related carbon dioxide emissions by making it available for the production of several hundred million tonnes of green steel. The process proceeds through rapid liquid-state reduction, chemical partitioning, as well as density-driven and viscosity-driven separation between metal and oxides. We show the underlying chemical reactions, pH-neutralization processes and phase transformations during this surprisingly simple and fast reduction method. The approach establishes a sustainable toxic-waste treatment from aluminium production through using red mud as feedstock to mitigate greenhouse gas emissions from steelmaking. KW - Multidisciplinary PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594424 DO - https://doi.org/10.1038/s41586-023-06901-z SN - 0028-0836 VL - 625 IS - 7996 SP - 703 EP - 709 PB - Springer Science and Business Media LLC AN - OPUS4-59442 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leers, K. A1 - Arnold, U. A1 - Herzel, Hannes A1 - Adam, Christian A1 - Burkhardt, J. T1 - Thermochemically Treated Sewage Sludge Ash From Pilot-Scale Production as P-Fertilizer for Spring Wheat and Maize in Different Soil Conditions N2 - Background P-fertilizers made from sewage sludge ash (SSA) may be suitable substitutes for rock phosphate (RP)-based fertilizers and contribute to sustainable use of waste. In this context, the thermochemical AshDec treatment of SSA (TC-SSA) has been continuously improved and has emerged as a possible method to produce plant-available and low-pollutant P-fertilizers. Aim Evaluation of the P-fertilizer efficacy of TC-SSA produced in pilot trials in vegetation experiments with different plants, soils, and fertilizer doses. Methods TC-SSA was tested in pot experiments for spring wheat and maize on different soils and at two doses (0.2 and 0.4 g fertilizer P pot−1) and is compared to untreated SSA (USSA), RP, Struvite, triple superphosphate (TSP), and a control without P-fertilization (Zero P). Pot experiments are complemented by an analysis of fertilizer P-solubility. Results P-solubility of SSA with different extraction methods increased due to the thermochemical treatment, whereas the water-insoluble property remained. In contrast to RP or USSA, TC-SSA enriched calcium–acetate–lactate extractable soil P to the same extent as TSP. Plant biomass and P-uptake increased with TC-SSA compared to Zero P, RP, and USSA and were in most cases equal to TSP fertilization under different soil conditions. In contrast, the effects of RP and USSA varied among soils but, mostly, did not exceed plant biomass and P-uptake of the unfertilized control. Conclusion TC-SSA has an increased fertilizer efficacy compared to USSA and is an effective P-fertilizer for spring wheat and maize in different soil conditions. KW - Phosphorus KW - Fertilizer KW - Thermochemical KW - Maize PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648251 DO - https://doi.org/10.1002/jpln.70035 SN - 1522-2624 VL - 189 IS - 1 SP - 81 EP - 93 PB - Wiley-VCH AN - OPUS4-64825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -