Pharmaceutical load in sewage sludge and biochar produced by hydrothermal carbonization.
We investigated the removal of twelve pharmaceuticals in sewage sludge by hydrothermal carbonization (HTC), which has emerged as a technology for improving the quality of organic waste materials producing a valuable biochar material. In this study, the HTC converted sewage sludge samples to a biochar product within 4h at a temperature of 210 °C and a resulting pressure of about 15 bar. Initial pharmaceutical load of the sewage sludge was investigated as well as the residual concentrations in biochar produced from spiked and eight native sewage sludge samples from three waste water treatment plants. Additionally, the solid contents of source material and product were compared, which showed a considerable increase of the solid content after filtration by HTC. All pharmaceuticals except sulfamethoxazole, which remained below the limit of quantification, frequently occurred in the investigated sewage sludges in the μg/kg dry matter (DM) range. Diclofenac, carbamazepine, metoprolol and propranolol were detected in all sludge samples with a maximum concentration of 800 μg/kgDM for metoprolol. HTC was investigated regarding its contaminant removal efficiency using spiked sewage sludge. Pharmaceutical concentrations were reduced for seven compounds by 39% (metoprolol) to≥97% (carbamazepine). In native biochar samples the four compounds phenazone, carbamazepine, metoprolol and propranolol were detected, which confirmed that the HTC process can reduce the load of micropollutants. In contrast to the other investigated compounds phenazone concentration increased, which was further addressed in thermal behaviour studies including three structurally similar potential precursors.
Institut für Energie- und Umwelttechnik e. V., IUTA (Institute of Energy and Environmental Technology), Bliersheimer Str. 58-60, 47229 Duisburg, Germany; Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany. Electronic address: vomEyser@iuta.de.
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vom Eyser
Hamburg University of Technology, Eißendorfer Str. 42, 21073 Hamburg, Germany. Electronic address: aww@tuhh.de.
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Palmu
Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstraße 2, 45141 Essen, Germany. Electronic address: torsten.schmidt@uni-due.de.
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Schmidt
Institut für Energie- und Umwelttechnik e. V., IUTA (Institute of Energy and Environmental Technology), Bliersheimer Str. 58-60, 47229 Duisburg, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstraße 2, 45141 Essen, Germany. Electronic address: tuerk@iuta.de.
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Tuerk
D002606:Charcoal / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D012722:Sewage; D014874:Water Pollutants, Chemical; C540010:biochar; D002606:Charcoal
HTC; Hydrochar; Micropollutants; Pyrazolones; Sewage sludge conversion; Waste treatment