Some tropical cyanobacteria have spread to temperate freshwaters during the last decades. To evaluate their further development in temperate lakes, we studied the temperature- and light-dependent growth of three invasive (Cylindrospermopsis raciborskii, Anabaena bergii and Aphanizomenon aphanizomenoides) and three native (Aphanizomenon gracile, Aphanizomenon flos-aquae and Anabaena macrospora) cyanobacterial species (Nostocales) from German lakes. We also included one potentially invasive (Aphanizomenon ovalisporum) Nostocales species. We conducted semi-continuous culture experiments and a microcosm experiment along a natural light gradient. Temperature data were used to design a model to simulate the development of selected species according to three temperature scenarios (past, present and future). Native species had significantly higher growth rates than invasive species and the potential invader A. ovalisporum at low temperatures (<= 10 °C), while the opposite was true at high temperatures (>= 35 °C). Maximum growth rates of A. ovalisporum, A. aphanizomenoides and C. raciborskii were clearly higher than those of A. bergii and the native species. Regarding light-dependent growth, significant differences were found between single species but not between all native and invasive species. The model simulation demonstrates a shift in dominance from the native A. gracile in the historic scenario to C. raciborskii populations in the future scenario, in which also the potential invader A. ovalisporum is able to establish populations in temperate lakes. Our findings suggest that any further temperature increase would promote the growth and development of Nostocales species in general, and that of the invasive species in particular, and would enable a more northward expansion of A. ovalisporum.

Within the study “IC-Pharma” a graphical benchmark of the occurrence of 30 priority pharmaceutical active compounds (PhACs) covering different therapeutic classes such as analgesics, antibiotics, lipid lowering drugs, beta blockers, tranquilizers, and cytostatics in the urban water cycle was conducted. The results are based on an extensive data set collected during several monitoring campaigns in Berlin and the Canton Zurich. This benchmark of the occurrence of priority pharmaceuticals allows water practitioners from other sites to compare detected concentrations of priority PhACs in STP effluents, surface water and groundwater.

Over the past decade, membrane bioreactors have been increasingly implemented to purify municipal wastewater. However, even with submerged modules which offer the lowest costs, the membrane bioreactor (MBR) technology remains in most cases more expensive than conventional activated sludge processes. In addition, the European municipal MBR market is to date a duopoly of two non-European producers, despite many initiatives to develop local MBR filtration systems. In 2005, the European Commission decided to finance four projects dedicated to further technological development of MBR process: the four projects AMEDEUS, EUROMBRA, MBR-TRAIN and PURATREAT were implemented from October 2005 up to December 2009 and joined their efforts within the coalition “MBR-Network” (www.mbr-network.eu). The present report synthesises the major outcomes of the project AMEDEUS, conducted from October 2005 up to May 2009. The AMEDEUS research project aimed at tackling both issues of accelerating the development of competitive European MBR filtration technologies, as well as increasing acceptance of the MBR process through decreased capital and operation costs. The project targets the two market segments for MBR technology in Europe: the construction of small plants (semi-central, 50 to 2,000 population equivalent or p.e., standardized and autonomous), and the medium-size plants (central, up to 100.000 p.e.) for plant upgrade.

Microcystins (MCYSTs) are a group of structurally similar toxic peptides produced by cyanobacteria (“blue-green algae”) which occur frequently in surface waters worldwide. Reliable elimination is necessary when using these waters as drinking watersources.Bankfiltrationandartificial groundwaterrecharge utilize adsorption and degradation processes in the subsurface, commonlythroughsandandgravel aquifers, for the elimination of a wide range of substances during drinking water (pre-) treatment. To obtain parameters for estimating whether MCYST breakthrough is likely in field settings, we tested MCYST elimination in laboratory experiments (batch experiments, column experiments) under a range of conditions. Adsorption coefficients (kd-values) obtained from batch studies ranged from 0.2 mL/g for filter sand to 11.6 mL/g for fine grained aquifer materials with 2% fine grains (<63 µm) and 0.8% organic matter. First order degradation rates in column studies reached 1.87 d-1 under aerobic conditions and showed high variations under anoxic conditions (<0.01-1.35 d-1). These results show that, next to sediment texture, redox conditions play an important role for MCYST elimination during sediment passage. Biodegradation was identified as the dominating process for MCYST elimination in sandy aquifer material.

Within the 3.5 year ENREM project (Enhanced Nutrient REmoval in Membranebioreactors) in Berlin-Margaretenhöhe a novel and patented process was investigated to demonstrate the feasibility of a semi-decentralised solution reaching high effluent requirements set by the water authority of Berlin. This novel process could be a solution for suburban areas of Berlin which are not connected to central sewer system. The biological process combines enhanced biological phosphorus removal (EBPR) with post denitrification in MBR technology without dosing of any carbon sources. The process configuration of this demonstration plant enables advanced wastewater nutrients removal (C, P and N) and could be a promising option for wastewater treatment wherever high effluent qualities are required. A second prototype MBR system was operated in parallel, applying a different biological process, e.g. without biological phosphorus removal, enabling a comparison of these different technological approaches. The demonstration plant showed high elimination rates for COD (>95%), phosphorus (>99%) and nitrogen (up to 98%) when operated within the appropriate range of design conditions. The operational experience within the first years showed that there is a possibility for process stabilisation by changing the ratio of the process steps. For this reason the volume of the anoxic zone was enlarged by reducing the aerobic volume in Feb 2008. The positive effects could be seen on the basis of the effluent concentrations after a short period of adaptation. The membrane filtration performance was very reliable with a new cleaning strategy: Two membranes were operated alternating with an operational flux of 15 – 20 L/m²/h and a maintenance cleaning with low chemical concentration. Different cleaning agents were used in order to evaluate the cleaning efficiencies. An economical evaluation of the demonstration plant was performed in comparison to the existing wastewater treatment costs of app. 7 €/m3 by trucking away and the prototype MBR plant. Operated on the same site, the two MBR systems were used to calculate the actual costs, in relation to the effluent quality, and to perform a scale-up up to 5000 pe considering four different effluent quality classes. The results showed that the ENREM process applied in the demonstration plant is economically an alternative for plant sizes of 5000 pe and larger. For plant sizes smaller than 5000 pe, the prototype MBR system equipped with precipitation and a downstream adsorption filter for enhanced phosphorus removal proofed to be the more viable solution.

The project OXIRED was initiated to assess the potential of a combination of natural systems such as bank filtration (BF) and artificial recharge (AR) and oxidation processes in order to improve the degradability of DOC and the removal of trace organics during water treatment. In this literature study, treatment schemes, which combine subsurface passage with oxidation processes, were evaluated with regard to the potential removal of DOC and trace organics, by theoretical considerations and case study analyses. The objectives were i) to estimate the degradation of bulk organic matter and trace organics in such combined systems, ii) to assess the potential for toxic by-products and iii) to describe different possible schemes combining natural systems (BF & AR) and oxidation processes. Available data generally shows good removal of the substances identified as persistent during BF & AR by oxidation processes. Carbamazepine, for example, is poorly degradable during bank filtration, but ozonation leads to a transformation of more than 97%. If ozonation alone does not suffice, advanced oxidation processes may enhance the transformation. E.g. literature gives a values of < 50% removal of Iopamidol by ozonation. However, transformation increases up to 88% using advanced oxidation processes, such as O3/H2O2 and O3/UV. Investigations on the formation of possible toxic by-products have shown the general possibilities to control the formation of bromate by decreasing the pH, avoiding free dissolved ozone in the reactor and/or by adding H2O2. Only a low risk of exposure of the potentially forming nitrosamines in drinking water after artificial recharge could be identified. Especially the cancerogenic metabolite NDMA is degraded during subsurface passage. Three reference treatment schemes were identified: (A): surface water is treated via oxidation before infiltration into artificial recharge ponds.(B): a river bank filtration with short retention times (<5 days) is used as a pretreatment step before the successive oxidation and artificial recharge (AR). (C1/C2): oxidation is applied subsequent to subsurface passage after bank filtration and artificial recharge. Due to the possible formation of toxic by-products and the increased assimilable DOC in scheme C (Examples for C1 Mülheim Styrum-East and Le Pecq Croissy & C2 Prairie Waters Project and the Bi´eau Process) a post-treatment including disinfection after oxidation is necessary. Additional post-treatment in schemes A (implemented at Mülheim Dohne) and B depends on the redox conditions and the travel times during the subsurface passage. However, although there is a lack of practical data, the enhancement of BDOC via oxidation prior to the underground passage seems theoretically more promising than the reverse configuration. It is therefore recommended that any further experimental program in OXIRED should focus on the schemes A and B and include a cost-benefit analysis of the additional first BF step.