Für die Gewinnung von Braunkohle ist die Absenkung des Grundwasserspiegels im Rheinischen Braunkohlerevier notwendig. Die große Ausdehnung der Tagebaue, sowohl in der Fläche als auch in der Tiefe, erfordert dabei eine über mehrere Jahrzehnte anhaltende Entwässerung der Lockergesteinsschichten. Hierfür werden Sümpfungsbrunnen verwendet, die bis in eine Tiefe von 750 m reichen. Im gesamten Rheinischen Braunkohlerevier werden von der RWE Power AG ca. 1.500 solcher Brunnen zur Entwässerung der Tagebaue eingesetzt.

Food production in Europe is dependent on imported phosphorus (P) fertilizers, but P use is inefficient and losses to the environment high. Here, we discuss possible solutions by changes in P management. We argue that not only the use of P fertilizers and P additives in feed could be reduced by fine-tuning fertilization and feeding to actual nutrient requirements, but also P from waste has to be completely recovered and recycled in order to close the P balance of Europe regionally and become less dependent on the availability of P-rock reserves. Finally, climatesmart P management measures are needed, to reduce the expected deterioration of surface water quality resulting from climate-change-induced P loss.

Im Rahmen des Forschungsprojekts SEMA ist die Prognosequalität eines Alterungsmodells anhand der TV-Inspektionsdaten der Stadt Braunschweig geprüft worden. Die Qualität der Prognose wurde auf der Grundlage einer Probe von 35.826 Inspektionen bewertet. Die Inspektionen wurden mittels eines substanzbasierten Modells klassifiziert. In einem zweiten Schritt wurde das statistische Modell KANEW-Z angewandt, um die Kanalalterung zu simulieren. Der Vergleich der Inspektions- mit den Simulationsergebnissen zeigt, dass das Modell in der Lage ist, die Zustandsverteilung des Systems ziemlich genau wiederzugeben. Die Ergebnisse sind auch ermutigend auf individueller Haltungsebene. Im Allgemeinen zeigt das Alterungsmodell viel bessere Ergebnisse als ein einfaches lineares Alterungsmodell. Schlussfolgernd unterstreichen die Ergebnisse das Interesse und den potentiellen Nutzen der Anwendung von Alterungsmodellen zur Unterstützung von Asset-Management-Strategien.

Commercialisation of nutrient recovery technologies are progressing across Europe, with a contract signed earlier this year to recycle phosphorus from 60,000 tons of sewage sludge ash. This article looks at progress and options from other companies against market barriers such as raw material prices and legal frameworks.

The theoretical work presented here analyses various process chains for the energetic utilisation of municipal sewage sludge in their energy and greenhouse gas balance taking into account the hydrothermal carbonisation (HTC), based on the operating data of an HTC pilot plant. In the comparison with reference processes for sewage sludge dewatering (centrifuge, chamber filter press) the HTC with this offers energetic advantages with the treatment of digested sludge through high energy credit notes in the incineration and relatively small additional expenditure if the process can be operated via waste heat. For raw sludges without digestion the HTC offers no advantages as the energe tic advantage of the high calorific value are balanced out through additional outlays (natural gas, increased return loading). Decisive factors with the energetic evaluation of the HTC process are here the internal heat management and the biogas yield from the HTC process water. To be noted is, however, that the refractory COD in the process water can lead, via the return loading of the wastewater treatment plant, to considerably increased COD discharge values, which the introduction of an HTC in many cases would prevent. Along with the energy balance the HTC technology for sewage sludge should therefore be comprehensively evaluated in large-scale trials in order to investigate more accurately the economic efficiency and environmental relevance of the process.

This paper reports about experiences gathered from five on-line monitoring campaigns in the sewer systems of Berlin (Germany), Graz (Austria), Lyon (France) and Bogota (Colombia) using UV-VIS spectrometers and turbidimeters. The influence of local calibration on the quality of on-line COD measurements of wet weather discharges has been assessed. Results underline the need to establish local calibration functions for both UV-VIS spectrometers and turbidimeters. It is suggested to practitioners to calibrate locally their probes using at least 15-20 samples. However, these samples should be collected over several events and cover most of the natural variability of the measured concentration. For this reason, the use of automatic peristaltic samplers in parallel to on-line monitoring is recommended with short representative sampling campaigns during wet weather discharges. Using reliable calibration functions, COD loads of CSO and storm events can be estimated with a relative uncertainty of approximately 20 %. If no local calibration is established, concentrations and loads are estimated with strong errors questioning the reliability and meaning of the on-line measurement. Similar results have been obtained for TSS measurements.

Hydrogeochemical and hydrodynamic surface/groundwater interactions were investigated at the urban floodplain aquifer in Delhi, India. The heavily polluted Yamuna River is in hydraulic contact to the groundwater and river seepage results in a contamination plume. A conceptual redox zonation was developed based on the occurrence or absence of terminal electron acceptors. The redox zonation shows an inverted zonation from sulphate-reducing conditions close to the river over manganese- and iron-reducing conditions to a mixed oxic/suboxic zone. This study shows that the occurrence of problematic substances such as ammonium and arsenic in the groundwater is a consequence of the high load of untreated sewage in the river in combination with losing river conditions. Sequential extraction of aquifer material was performed to obtain information on geochemical availability of arsenic associated with different mineral phases and binding forms. Geogenic and anthropogenic arsenic sources contribute to overall arsenic concentration, and arsenic is found to be attributed mainly to amorphous iron oxide and sulphidic phases in the sediment. The contamination plume at the urban floodplain aquifer makes the groundwater unfit for drinking water purposes.

Zum Erzielen guter Erträge in der Landwirtschaft und in Ermangelung nennenswerter fossiler Vorkommen müssen alljährlich ca. 1 Million Tonnen mineralisch gebundenen Phosphors nach Europa importiert werden. Gleichzeitig werden Rückgewinnungs- und Recyclingpotentiale dieser lebenswichtigen Ressource nicht bzw. wie im Falle des Klärschlamms nur zu einem geringen Anteil genutzt. In den letzten Jahren wurden zahlreiche technische Verfahren entwickelt, die dazu beitragen sollen, den Nährstoff Phosphor alternativ zur umstrittenen Praxis der Klärschlammausbringung wieder für die Landwirtschaft verfügbar und nutzbar zu machen. Insbesondere praxisnahe Lösungen haben bereits den Sprung in die großtechnische Umsetzung geschafft bzw. stehen kurz davor. Nationale wie internationale Initiativen widmen sich dem Zusammenbringen von Akteuren aus Wissenschaft, Politik und Wirtschaft, um die Implementierung voranzubringen. Für ein Nährstoffrecycling genügt es nicht, bei der Nährstoffrückgewinnung aufzuhören. To sustain good harvests, about one million tons of mineral phosphorus have to be imported to Europe annually, while the potentials to recover and recycle this essential resource remain untapped or are just inefficiently used as in the case of sewage sludge. In the recent years various technical alternatives to the traditional but disputed application of sludge in agriculture have been developed to recover the nutrient. Especially user friendly solutions have already made their way to full-scale or at least pilotscale application. National and international initiatives are dedicated to bridge the gaps between the relevant sectors of science, policy and industry to finally foster wide-spread implementation of phosphorus recovery and recycling. It is not enough to just recover nutrients. To achieve real recycling, the gap between recovery and return of phosphorus into the nutrient cycle needs to be closed. The supply side needs to match with the requirements of the demand side.