In Berlin gibt es nur noch wenige abgelegene kleine Einzugsgebiete (<1%), die nicht an das zentrale Abwassersystem angeschlossen sind. Aber in den neuen EU-Ländern ist der Anteil an der Bevölkerung, die nicht an eine zentrale Abwasserreinigung angeschlossen sind, noch deutlich höher. Besonders in dünn besiedelten Gebieten gibt es immer noch sehr viele Abwassersammelgruben (abflusslos oder mit Versickerung). Für empfindliche Einzugsgebiete (Badeseen, Wassersport, Fremdenverkehr) könnte für die Einleitung von gereinigtem Abwasser eine über die Mindestanforderung in der Abwasserverordnung hinausgehende weitergehende Nährstoffentfernung von der zuständigen Behörde gefordert werden. Das Membranbelebungsverfahren (MBR) könnte eine technische und auch wirtschaftliche Lösung bieten, um eine semi-zentrale Erschließung in Gebieten mit einem sensitiven Vorfluter (Gewässer) zu realisieren. Mittels eines Membranprozesses kann die vollständige Desinfektion und weitgehende biologische Phosphorentfernung bis auf 0.1mgP/L oder niedriger ohne Fällmittel erreicht werden (Gnirss et al., 2003a, Gnirss et al., 2003b). Damit kann der Standard der EU-Richtlinie für Badegewässer direkt im Ablauf der kleinen Kläranlage erreicht werden und die Eutrophierung im Oberflächenge-wässer reduziert werden. Die Umsetzung von MBR-Anlagen in kleinen oder mittleren Einzugsgebieten ist mittels schlüsselfertiger Containereinheiten möglich, wodurch die Investitionskosten gesenkt und die üblichen Unannehmlichkeiten von Kläranlagen wie Geruchs- und Lärmemissionen vermieden werden können. Dieser Artikel stellt die Vorteile und die Kosten der MBRTechnologie für die dezentrale Erschließung eines Siedlungsgebietes im Norden von Berlin vor und vergleicht sie mit dem konventionellen Verfahren. Dabei werden die technischen Grundlagen der Demonstrationsanlage ausführlich erläutert, und die wichtigsten Designkriterien für die MBR-Anlage und das Druckentwässerungsnetz vorgestellt.

Three single-filament isolates of Aphanizomenon flos-aquae from two German lakes were found to produce remarkable amounts of the cyanobacterial epatotoxin cylindrospermopsin (CYN). CYN-synthesis of the strains were evidenced both by LC-MS/MS analysis and detection of PCR products of gene fragments which are implicated in the biosynthesis of the toxin. The strains contain CYN in the range of 2.3–6.6 mg gK1 of cellular dry weight. To our knowledge this is the first report of CYN in A. flos-aquae.

Given the important cost reduction of the membrane bioreactor technology in the last years, this advanced treatment process has now become cost-competitive with other conventional technologies. A cost estimation analysis undertaken with few remaining unsewered and remote areas of Berlin showed that the implementation of semi-central sanitation scheme with a local membrane bioreactor plant would lead to similar costs than the connection to the central sewer, but with a superior effluent quality. For such small systems, some design issues have to be considered in order to optimise the costs and the operation regime, such as plant capacity increase, buffer capacity, process configuration and membrane flux.

Two configurations of membrane bioreactors were identified to achieve enhanced biological phosphorus and nitrogen removal, and assessed over more than two years with two parallel pilot plants of 2m³ each. Both configurations included an anaerobic zone a head of the biological reactor, and differed by the position of the anoxic zone: standard pre-denitrification, or postdenitrification without dosing of carbon source. Both configurations achieved improved phosphorus removal. The goal of 50mgP/L in the effluent could be consistently achieved with two types of municipal waste water, the second site requiring a low dose of ferric salt ferric salt < 3mgFe/L. The full potential of biological phosphorus removal could be demonstrated during phosphate spiking trials, where up to 1mg of phosphorus was biologically eliminated for 10mg BOD5 in the influent. The postdenitrification configuration enabled a very good elimination of nitrogen. Daily nitrate concentration a slow as 1mg N/L could be monitored in the effluent in some periods. The denitrification rates, greater than those expected for endogenous denitrification, could be accounted for by the use of the glycogene pool, internally stored by the denitrifying microorganisms in the anaerobic zone. Pharmaceuticals residues and steroids were regularly monitored on the two parallel MBR pilot plants during the length of the trials, and compared with the performance of the Berlin-Ruhleben WWTP. Although some compounds such as carbamazepine were persistent through all the systems, most of the compounds could be better removed by the MBR plants. The influence of temperature, sludge age and compound concentration could be shown, as well as the significance of biological mechanisms in the removal of trace organic compounds.

A modelling study was carried out to provide a process-based quantitative interpretation of the biogeochemical changes that were observed during an ASR experiment in which reclaimed water was injected into a limestone aquifer at a field-site near Bolivar, South Australia. A site-specific conceptual model for the interacting hydrodynamic and biogeochemical processes that occur during reclaimed water ASR was developed and incorporated into an existing reactive multi-component transport model. The major reactive processes considered in the model were microbially mediated redox reactions, driven by the mineralisation of organic carbon, mineral precipitation/ dissolution and ion exchange. The study showed that the geochemical changes observed in the vicinity of the ASR well could only be adequately described by a model that explicitly considers microbial growth and decay processes, while an alternative, simpler model formulation based on the assumption of steady state biomass concentration failed to reproduce the observed hydrochemical changes. However, both, the simpler and the more complex model approach were able to reproduce the geochemical changes further away from the injection/extraction well. These changes were interpretated as a result of the combined effect of ion exchange, calcite dissolution and mineralisation of dissolved organic carbon.

This paper presents the results on the occurrence and fate of antibiotic residues during bankfiltration obtained from a study carried out in terms of an interdisciplinary project at three transects in Berlin, Germany. Six antibiotic compounds and two metabolites were detected at ng/L concentrations in water samples from the lakes or in the monitoring wells of the transects. Clarithromycin, roxithromycin (macrolide), trimethoprim (synergist for sulfonamides) and acetyl-sulfamethoxazole (metabolite) are efficiently removed by bank filtration. Residues of clindamycin (lincosamid) and dehydro-erythromycin (metabolite) were completely attenuated during the soil passage. For sulfamethoxazole (sulfonamide), a significant but not complete removal during bank filtration was observed. It was the only compound that could be detected at tracelevels in samples collected from water-supply wells.

Managed aquifer recharge is an increasingly popular technique to secure and enhance water supplies. Among a range of recharging techniques, single-well aquifer storage and recovery (ASR) is becoming a common option to either augment drinking water supplies or facilitate reuse of reclaimed water. For the present study a conceptual biogeochemical model for reclaimed water ASR was developed and incorporated into an existing reactive multicomponent transport model. The conceptual and numerical model for carbon cycling includes various forms of organic and inorganic carbon and several reactive processes that transfer carbon within and across different phases. The major geochemical processes considered in the model were microbially mediated redox reactions, driven by the mineralization of organic carbon, mineral dissolution/ precipitation, and ion exchange. The numerical model was tested and applied for the analysis of observed data collected during an ASR field experiment at Bolivar, South Australia. The model simulation of this experiment provides a consistent interpretation of the observed hydrochemical changes. The results suggest that during the storage phase, dynamic changes in bacterial mass have a significant influence on the local geochemistry in the vicinity of the injection/extraction well. Farther away from the injection/extraction well, breakthrough of cations is shown to be strongly affected by exchange reactions and, in the case of calcium, by calcite dissolution.

Integrierte Produktpolitik ist ein sehr junges Gebiet, bei dem man kaum auf Erfahrungswerte zurückgreifen kann. Benötigt werden kreative Lösungsansätze, die sich auch unkonventioneller Mittel und Wege bedienen. Dies stellt höchste Anforderungen an die Lernbereitschaft aller Beteiligten. Dabei ist es wichtig, eingefahrene Gleise zu verlassen. Dazu zählt u.a., dass Investitionsentscheidungen nicht mehr von den Abschreibungszeiträumen der Geräte abhängen, sondern von der Funktions- und Einsatzfähigkeit und der Wartungsorganisation. Und genau an diesem Punkt setzt das Geschäftsmodell des ITZM an, unterstützt durch den rechtlich neu gesetzten Rahmen mit der grundlegenden neuen Philosophie- und Strategieausrichtung der Wiederverwendung („Used is Useful“) in der EG-Richtlinie über „Elektro- und Elektronik-Altgeräte“. Das ITZM besteht im Kern aus vier Säulen: der Gebrauchtmessgerätebörse, dem Testfeld für neue Messgeräte und –systeme, der Informationsplattform über das Internet und der Ingenieurberatung. Das ITZM führt die Anwender/Nutzer und Hersteller von Messgeräten und Messsystemen auf den Gebieten der Abwasserbehandlung, Wasserversorgung, Gewässerüberwachung, Produktionsüberwachung und Laboranalytik zusammen, um im Wege des Informationsaustausches umfassend ihre Kauf- und Verkaufswünsche erfüllt zu bekommen. Dazu bietet das ITZM über seine Internetplattform Informationen zu den Gerätschaften in Form von Testergebnissen, Literaturhinweisen, Anwendererfahrungen (Einrichtung eines Forums zum Informationsaustausch) sowie kompetente Ingenieurberatung an. Über das Testfeld werden Messgeräte/-systeme untersucht und erprobt, um die Leistungsversprechen der Hersteller unter realen Bedingungen zu ermitteln. Das ITZM bringt über die Messgerätebörse gebrauchte Geräte nach Überprüfung und evtl. Reparatur sowie Funktionsprüfung mit Qualitätsgarantie wieder in den Markt, realisiert Wartung und Kundendienst und sorgt für ein sehr gutes Preis/Leistungsverhältnis. Als neutrales und autark arbeitendes Unternehmen stellt die Beratung der potenziellen Nutzer einen wesentlichen Faktor dar. In Sinne dieser Machbarkeitsstudie konnte nachgewiesen werden, dass die Gründung eines Unternehmens ITZM auf soliden Füßen steht. Konservative Abschätzungen über Mittelbedarf (Geschäfts- und Investitionskosten) und den zu erwartenden Mittelzufluss aus den Geschäftszielen ergeben eine solide Geschäftsgrundlage. Das ITZM soll als eigenständige Rechtsperson am Standort Berlin gegründet werden. Dadurch wird der Standort Berlin gestärkt, der insbesondere als „Tor zum Osten“ ein neues, bedeutendes Instrument erhält. Denn nach Kenntnis der Verfasser dieser Machbarkeitsstudie existiert derzeit in Deutschland und Europa keine vergleichbare Einrichtung; ebenso ist keine Planung für eine solche bekannt. Mit dem ITZM werden Arbeitsplätze in Berlin gesichert und gleichzeitig auch neue, u.a. technologisch sehr anspruchsvolle geschaffen. Die Bevölkerung des Landes Berlin sowie eine Reihe umgebender Ortschaften, die von den Berliner Wasserbetrieben mit Trinkwasser versorgt oder deren Abwasser durch dieses Unternehmen entsorgt und gereinigt wird, sowie weitere Einrichtungen des Landes Berlin können bei Inanspruchnahme von Leistungen des ITZM direkt profitieren und damit Geld sparen. Das geschätzte Einsparvolumen allein für Berlin liegt bei konsequenter Umsetzung der vorgeschlagenen Maßnahmen in der Größenordnung von mehreren hunderttausend Euro/Jahr. Bei der Einrichtung des ITZM wird auch eine geeignete Kooperation mit dem KompentenzZentrum Wasser Berlin gGmbH (KWB) angestrebt, so dass auch das KWB auf dem Sektor der Messgeräte und Messsysteme auf eine Kompetenz zurückgreifen kann, die überregional und international von herausragender Bedeutung ist.

A suite of predictive quantitative models of phosphorus (P) dynamics in Lake Tegel and Schlachtensee has been developed. The results, specific to each lake, are set out below, together with general conclusions about management strategies, and some high priority areas for future research. Lake Tegel: 1. The inflow from the Havel to Lake Tegel has been estimated using both a discrete time step box model and a time integrated numerical model. There is good internal agreement between the 2 estimates of the Havel inflow as a mean fraction of the total inflows (~ 40 %) , as well as with the earlier work of Ripl (1993). The estimated residence times agree closely (~ 70 d). 2. There is considerable inter-annual and inter-seasonal variation in Havel inflows. The numerical model can be used to satisfactorily predict these as a function of the Havel discharge, OWA discharge, and water extraction (bank infiltration and recharge, r²=0.76). 3. Over the past 15 years Lake Tegel has been both a net source (1984-1992;2000-2002), and a net sink (1993 – 1999), for phosphorus. The Havel inflow is the most important component in the P budget of Lake Tegel. When the sediment is a source, the modelled internal P load is 2-4 fold of the OWA annual load. 4. The internal P load can be satisfactorily modelled (r²=0.72) as a function of the external P loads, the water works extractions, and the temperature and nitrate concentration in the hypolinmion. The sensitivity analyses indicate that temperature is the major controlling factor for the P release. The significance of nitrate has to be explored further, and identifying thresholds for parameters which trigger release remains to be done in years 2 and 3. 5.The sediment investigations indicate that the sediment P release is dominated by mineralisation, plus desorption at times of high mineralisation and FeS precipitation. 6. Sediment investigations indicate that artificial oxidation of the sediment surface will only impact on P release when the mineralisation is intense and sulphate reduction is prevented. 7. The internal store of mobilizable P in the sediments is small, the rate of mobilisation is high, and the water residence time is short; thus the internal P load will have no long term effects after the external load is reduced sufficiently (< 5 years, assuming an external load of zero). At present, the external P load is high enough to recharge the sediments. Schlachtensee: 1. The water balance of Schlachtensee can be modelled satisfactorily (r²=0.89) by considering precipitation, storm water discharges and a term to reflect groundwater flows, which yet needs to be validated. 2. Groundwater inflows, as unknown parameter, were determined from modelling by a constant groundwater inflow plus other variable components dependent on precipitation, the level of Schlachtensee, the extraction at Well Rehwiese and of the temperature; this still needs to be cross-checked with a more detailed analysis of groundwater data. 3. The long time development of the P concentration is dominated by the reduced external load from the OWA Beelitzhof. The modelled long term steady state is about 0.02 g P m3 (annual mean). Schlachtensee has been a sink for P since 1985. 4. Next to effects of the reduced external load, the P concentration in Schlachtensee is characterised by peaks occurring in autumn and winter. The cause is not conclusively identified, but is suspected to be due to loading from the steep shoreline, e.g. leaching P from fallen leaves or mobilisation of animal/human excreta deposited in the summer. 5. Modelling shows that in Schlachtensee the epilimnion exerts a dominant effect on the P dynamics. Although P accumulation occurs in the hypolimnion, this is only a small fraction of the total lake P content. P release is controlled mainly by temperature and redox conditions, as well as the hydrological regime. Whether or not thresholds for release can be identified from any of these remains to be investigated. 6.The sediment investigations indicate that the sediment P release is dominated by desorption due to FeS precipitation. 7. The internal store of mobilizable P in the sediments is small, the rate of mobilisation is moderate, and the water residence time is longer than Lake Tegel. Thus, though its contribution to the lake’s P pool is much smaller, the internal P load will continue to exert an effect for longer than in Lake Tegel after the removal of the external load. Assuming the external load to be zero, the mobilizable P-Pool will be released in about 5 years. Both lakes: Chlorophyll-a data is used to depict the reaction of phytoplankton biomass to reduced in-lake TP concentrations. Chlorophyll-a were recalculated without the phaeophytin correction, and investigations for TP thresholds that govern phytoplankton response were begun. TP thresholds in Lake Tegel appear to be higher (around 100 µg/L) than in Schlachtensee (around 30 µg/L). Further data evaluation, including analysis of monthly means and individual sampling dates, is needed. Management implications: 1. Lake Tegel and Schlachtensee have quite different behaviours and require different management strategies. The various models already developed provide a basis for exploring adapted management scenarios. An initial exploration has identified potentially effective strategies. 2. For Lake Tegel the results strongly point to the continuation of the current management strategy to limit the inflow of P rich Havel water into Lake Tegel, i.e. increasing the OWA discharge during summer, when the P concentration in the Havel, and the extraction by the Water Works, are at their highest. 3. As the P release from the sediment in Lake Tegel is mainly driven by the temperature above the lake bottom the stratification stability should be as high as possible.Therefore, operation of the aerators in a fashion to maintain the maximum possible stratification in summer is proving critically important. 4. The model results confirm that for Schlachtensee the P balance is no longer dominated by the inflows from the OWA Beelitzhof, thus any further efforts to reduce P loading will be more effective if concentrated on the other major external sources. 5. The dominant term in the P balance of Schlachtensee appears to be the autumn and winter deliveries, though the actual mode of delivery is still unclear. Identifying the source(s) is an important future research task. 6. Epilimnetic processes are dominant in Schlachtensee and thus no further measures are required to reduce the internal P loading from the sediments to the water column. Future Research Goals 1. Improving the P models for both lakes, for Lake Tegel particularly for the calculation of the internal loads and for Schlachtensee for calculating the external loads, 2. Developing the P models towards management models for both lakes by improving the calculation of the internal loads for Lake Tegel and the external loads for Schlachtensee, 3. Including model components for biological interactions and interfacing them within a transferable P process model to explain the process of trophic recovery, 5 4. Using the improved models for assessing the relative effects of external and internal measures aimed at modifying the P budget, e.g. seasonality of OWA output, aerator operation and seasonal changes in water residence time, 5. Analysing which responses of the lake components are continuous and which show thresholds, and identifying threshold values for the latter; in a second step including other lakes using literature and data provided by other partners, 6. Conducting specifically targeted field investigations to fill gaps, to validate the models and as supplement of monitoring by ILAT in order to uphold the long-term data series, as detailed in the proposal for continuation of the project; 7. Using the outcomes of 1 – 6 for optimised management scenarios for the two Berlin lakes. Together with the evaluation of literature and data from other lakes undergoing trophic recovery, general guidance on managing restoration and predictions of responses to reduced nutrient loading will be developed.