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Veröffentlichung Monitoring von Klärschlammaschen(2014) Krüger, Oliver; Adam, Christian; Roskosch, AndreaVon den etwa zwei Millionen Tonnen Klärschlamm, die jährlich in Deutschland anfallen, wird aktuell knapp die Hälfte landwirtschaftlich verwertet, während der Rest entweder in Monoverbrennungsanlagen oder in Kohlekraftwerken und Zementfabriken verbrannt wird. Der direkte Einsatz des Klärschlamms in der Landwirtschaft
wird aufgrund der Belastung mit Schwermetallen und insbesondere mit organischen Schadstoffen zunehmend kritisch gesehen, auch von der Politik. So sieht beispielsweise der Koalitionsvertrag zwischen CDU, CSU und SPD für die 18. Legislaturperiode des Deutschen Bundestags den Ausstieg aus der landwirtschaftlichen Klärschlammverwertung vor. Der Anteil der Verbrennung an der Klärschlammentsorgung dürfte deshalb in Zukunft zunehmen. Während bei der Verbrennung zwar die organischen Schadstoffe nahezu vollständig abgebaut werden, gehen die im Schlamm enthaltenen Wertstoffe - insbesondere Phosphor - dem Wirtschaftskreislauf dauerhaft verloren, da die Aschen bisher hauptsächlich deponiert oder zum Bergversatz genutzt werden. Um das Rückgewinnungspotential für Wertstoffe aus Klärschlammaschen bewerten zu können, wurden in einem Vorhaben des Umweltforschungsplans fast sämtliche in Deutschland anfallenden Klärschlammaschen (KSA) aus 24 Monoverbrennungsanlagen über einen Zeitraum von einem Jahr beprobt und grundlegend charakterisiert. Es wurde festgestellt, dass in knapp 300.000 Tonnen Klärschlammasche pro Jahr etwa 19.000 Tonnen Phosphor enthalten, was 13 Prozent der Phosphormenge entspricht, die in Deutschland jährlich für Mineraldünger benötigt wird. Diese Menge könnte schon heute aus Aschen zurückgewonnen werden, die bei der separaten Verbrennung von
Klärschlamm (Monoverbrennung) anfallen. Das Rückgewinnungspotential anderer Rohstoffe wie seltene Erden ist dagegen eher gering.Quelle: Krüger, Oliver; Roskosch, Andrea; Adam, Christian: Monitoring von Klärschlammaschen / Oliver Krüger ; Andrea Roskosch ; Christian Adam. - graph. Darst. In: ReSource : Abfall, Rohstoff, Energie ; Fachzeitschrift für nachhaltiges Wirtschaften. - (2014), H. 3, S. 8Veröffentlichung Combating cyanobacterial proliferation by avoiding or treating inflows with high P load ̶ experiences from eight case studies(2015) Abella, Sally E. B.; Chorus, Ingrid; Litt, Arni; Fastner, Jutta; Morabito, Giuseppe; Voeroes, Lajos; Pálffy, Károly; Straile, Dietmar; Kümmerlin, Reiner; Matthews, David; Phillips, M. GeoffIncreased external nutrient loads of anthropogenic origin, especially those of phosphorus (P), were one of the major causes of eutrophication during the first half of the twentieth century in Europe. They led to deterioration of lake ecosystems, particularly including noxious blooms of (potentially toxic) cyanobacteria. From the 1970-1980s, strategies to decrease the phosphorus loads from sewage were increasingly implemented, among them are the ban of phosphates in detergents, the expansion of sewer systems and improvement in wastewater treatment to remove nutrients. Case studies of eight lakes, whose response to point source reduction of phosphorus was observed over decades, show that a pronounced reduction of the phosphorus load from point sources can be achieved either by the diversion of inflows carrying high loads, by upgraded sewage treatment, or by phosphorus precipitation in the major tributary directly before its inflow into the water body. Outcomes demonstrate that in order to effectively control cyanobacterial blooms, the measures taken need to reduce in-lake concentrations of total phosphorus below 20-50 Ţg L-1, with this threshold varying somewhat between lakes depending in particular on hydromorphological and biological conditions. Whether and when load reduction succeeds in controlling cyanobacteria depends primarily on the load remaining after remediation and on the water residence time.
Quelle: http://link.springer.com/Veröffentlichung Nutrient criteria for surface waters under the European Water Framework Directive: Current state-of-the-art, challenges and future outlook(2019) Poikane, Sandra; Claussen, Ulrich; Kelly, Martyn G.; Salas Herrero, Fuensanta; Leujak, WeraThe aim of European water policy is to achieve good ecological status in all rivers, lakes, coastal and transitional waters by 2027. Currently, more than half of water bodies are in a degraded condition and nutrient enrichment is one of the main culprits. Therefore, there is a pressing need to establish reliable and comparable nutrient criteria that are consistent with good ecological status. This paper highlights the wide range of nutrient criteria currently in use by Member States of the European Union to support good ecological status and goes on to suggest that inappropriate criteria may be hindering the achievement of good status. Along with a comprehensive overview of nutrient criteria, we provide a critical analysis of the threshold concentrations and approaches by which these are set. We identify four essential issues: (1) Different nutrients (nitrogen and/or phosphorus) are used for different water categories in different countries. (2) The use of different nutrient fractions (total, dissolved inorganic) and statistical summary metrics (e.g., mean, percentiles, seasonal, annual) currently hampers comparability between countries, particularly for rivers, transitional and coastal waters. (3) Wide ranges in nutrient threshold values within shared water body types, in some cases showing more than a 10-fold difference in concentrations. (4) Different approaches used to set threshold nutrient concentrations to define the boundary between "good" and "moderate" ecological status. Expert judgement-based methods resulted in significantly higher (less stringent) good-moderate threshold values compared with data-driven approaches, highlighting the importance of consistent and rigorous approaches to criteria setting. We suggest that further development of nutrient criteria should be based on relationships between ecological status and nutrient concentrations, taking into account the need for comparability between different water categories, water body types within these categories, and countries. © 2019 The Authors. Published by Elsevier B.V.Veröffentlichung Decades needed for ecosystem components to respond to a sharp and drastic phosphorus load reduction(2020) Beulker, Camilla; Köhler, Antje; Chorus, Ingrid; Fastner, JuttaLake Tegel is an extreme case of restoration: inflow treatment reduced its main external phosphorus (TP) load 40-fold, sharply focused in time, and low-P water flushed the lake volume ~ 4 times per year. We analysed 35 years of data for the time TP concentrations took to decline from ~ 700 to 20-30 (my)g/l, biota to respond and cyanobacteria to become negligible. The internal load proved of minor relevance. After 10 years, TP reached 35-40 (my)g/l, phytoplankton biomass abruptly declined by 50% and cyanobacteria no longer dominated; yet 10 years later at TP < 20-30 (my)g/l they were below quantifiable levels. 20-25 years after load reduction, the lake was stably mesotrophic, macrophytes had returned down to 6-8 m, and vivianite now forms, binding P insolubly in the sediment. Bottom-up control of phytoplankton through TP proved decisive. Five intermittent years with a higher external P load caused some 're-eutrophication', delaying recovery by 5 years. While some restoration responses required undercutting thresholds, particularly that of phytoplankton biomass to TP, resilience and hysteresis proved irrelevant. Future research needs to focus on the littoral zone, and for predicting time spans for recovery more generally, meta-analyses should address P load reduction in combination with flushing rates. The Author(s) 2020