Cylindrospermopsis raciborskii, a cyanobacterium of tropical origin, can produce the toxin cylindrospermopsin (CYN). This originally tropical cyanobacterium (blue-green alga) had spread to the waters of the Berlin area. Cylindrospermopsin had been detected in two lakes in the area, but none of the C. raciborskii strains isolated here so far were found to produce the toxin. The main objectives of the CYLIN project were therefore to analyze the distribution and regulation of C. raciborskii and cylindrospermopsin and to determine which cyanobacteria are producing this toxin in order to establish a basis to predict the further course of development of this species and the related health hazards for humans. The CYLIN project was implemented as a three-part program. A screening program was first conducted in 2004 to test regional water bodies for the presence of cylindrospermopsin and potential CYN-producing cyanobacteria in order to obtain an overview of their distribution in the study region. A total of 142 regional water bodies were sampled once each in this qualitative analysis of cylindrospermopsin and cyanobacteria. The screening program was followed by a monitoring program designed to generate quantitative data on the concentrations of dissolved CYN, particulate CYN, cyanobacteria and target environmental parameters at 20 selected lakes, which were sampled 3 times each. Furthermore, we investigated the seasonal dynamics of these parameters at two selected lakes in 2004 and 2005. Apart from this we isolated different cyanobacterial strains and conducted chemical and molecular biological analyses of CYN and CYN-coding genes, in order to identify CYN-producing cyanobacteria. The results show that C. raciborskii and CYN are much more widespread than was previously assumed for the region. C. raciborskii was detected in 22 % of the investigated water bodies, and cylindrospermopsin in 52 %. Additionally, two other toxic cyanobacteria of tropical origin were found for the first time in the Berlin-Brandenburg region, Anabaena bergii and Aphanizomenon aphanizomenoides. The mean and maximum CYN concentrations were 1 µg L-1 and 12 µg L-1, respectively. Since the particulate CYN fraction did not exceed 0.5 µg L-1, the dissolved CYN fraction was found to be responsible for the high CYN concentrations. The proposed guideline value for cylindrospermopsin in drinking water (1 µg L-1; Humpage and Falconer 2003) was exceeded 18 times at 8 different lakes. Although Aphanizomenon flos-aquae (Nostocales) has been unequivocally identified as a producer of cylindrospermopsin, the observed cylindrospermopsin concentrations cannot be attributed to this cyanobacterial species alone. Aphanizomenon gracile was also identified as a potential CYN-producing cyanobacterium. Based on the findings of the CYLIN project, we recommend that cylindrospermopsin be included as in hazard analyisis for drinking and bathing water quality assessments. To identify risk conditions associated with this cyanotoxin, further investigations are needed to identify all cyanobacteria that produce cylindrospermopsin and to elucidate the mechanisms regulating the occurrence of CYN-producing cyanobacteria, CYN synthesis by these organisms, and CYN decomposition in aquatic ecosystems. Our analysis of C. raciborskii population dynamics showed that its germination is temperature-dependent and its population growth light-dependent. Population size was determined by the time of germination, that is, the earlier the time of germination, the bigger the population. Based on these findings, it appears highly likely that the climate-related early rise in water temperatures over the course of the years has promoted the spread of this species to temperate regions. Our hypothesis for the future course of cyanobacterial and cyanotoxin development in German waters is as follows: The combination of trophic decline and global warming works to the general benefit of cyanobacteria of the order Nostocales and leads to a shift in cyanobacterial species and toxin composition. This may ultimately lead to an increase in the incidence of neurotoxins as well as cylindrospermopsin.

The Berlin Centre of Competence for Water organised, together with the International Water Association, the 2nd National Young Water Professionals Conference in Germany. This event was held on 4-5 June 2007 in Berlin and was following up on the first NYWP conference organised in Aachen in October 2005. It provided a forum for young researchers and professionals working in the membrane sector of the wastewater industry to present their work and meet their peers. The conference consisted on formal presentation of papers and posters, and an exchange with water industry professionals providing information on water career opportunities in Germany. This event was an initiative of “MBR-Network”, the European cluster on the membrane bioreactor technology, gathering about 50 European and international companies and institutions within the four FP6 projects Amedeus, Eurombra, MBR-Train and Puratreat (more info at www.mbrnetwork.eu). The technical program of the conference consisted mainly of contributions from German and international young water professionals including students, recent graduates and other professionals under the age of 35. This book contains most of the papers and posters which were presented at the Conference.

Access to microbiologically and chemically safe water is limited not only in developing countries, but also in transition countries and even in remote areas of developed countries. For these cases, decentralized water supply concepts such as point-of-use (POU), point-of-entry (POE) or small-scale system (SSS) technologies can be promising alternatives to centralized treatment concepts. Membrane-based treatment systems have gained importance for drinking water treatment in the developed countries. In principle, application of membrane technology is attractive also for the transition and developing countries, because it provides absolute barriers for control of hygienic hazards (Ultrafiltration (UF)) and because the modular construction enables implementation on each possible scale size. However membrane technology is still not affordable for the poorest part of the world population. The sustainable application of POU membrane system presumes that system should be operated without or with limited addition of chemicals, with limited possibility of regular backflushing and with low pressure, presumably hydrostatic. On the other hand, while the water needs for drinking and cooking for a family of four people constitute approx. 20 l/day, operation of POU UF system under low flux conditions is possible. One of the most important limitations for application of ultrafiltration in simple household devices, is membrane fouling. In order to overcome the reasons of the limited application of UF in POU systems, the better understanding of the UF process in these specific conditions and specially membrane fouling is needed. Recent studies have shown that dissolved or colloidal polysaccharides and proteins and their interactions with the membrane and between macromolecules might have more severe impact. During long term dead-end filtration, accumulation of the macromolecules on the membrane surface and increase of their concentration is severe. The interactions between those macromolecules in the conditions of high concentrations in the boundary layer affect the structure of the layer and its permeability. However, in most of the studies, only the foulant-membrane interactions are considered like relevant for reversibility of fouling. The foulant-foulant interactions in the boundary layer have been studied only superficially. Therefore, we systematically investigated the impact of polysaccharide and solution properties on UF membrane fouling in conditions of low flux and limited backflushing, under constant TMP conditions (hydrostatic pressure of 120 mbar - 150 mbar. Our experimental results lead us to the following conclusions: Regarding the initial stage of flux decline (0-80 ml permeate/cm2) the polysaccharide structure, and particularly availability of carboxyl groups, has a major impact on the membrane fouling, while the molecular weights of polysaccharides does not play a significant role (in the studied range of Mw 5-250 kDa). Such solution conditions as presence of metal ions and ionic strength are also detrimental for the fouling, while both metal ions and ionic strength have impact on the gel structure and properties, generally stabilizing it, and increasing the possibility of water trapping by hydrogen bonding, which leads to the higher permeability. However, independently of the initial solution conditions, after approx. 80 ml has been filtered through 1 cm2 of the membrane, flux becomes stable on the level of approx. 10 L/(hm2) over the whole period of operation (several weeks in some cases). We suppose that the gel layer formed by polysaccharides play a role of a “second” membrane on the surface of the PES UF membrane, keeping remaining permeability on the certain level, determined by the water retention properties of the gel structure. Regarding practical application, the obtained results open a new direction for the ultrafiltration in specific conditions of household systems. The long term ultrafiltration should be studied on natural waters to prove the flux stabilization phenomenon. This phenomenon may give a possibility to produce up to 10 L/h of water from 1 m2 of the membrane applying only 120 mbar of hydrostatic pressure (1.2 m water level difference) without backflushing or crossflow, which may simplify the design and maintenance of the system and significantly reduce its costs. Next activities in Techneau project will include the further evaluation of the long term ultrafiltration on natural waters; characterization of the impact of biofouling on the flux decline; and evaluation of the operational parameters of the Point-of-use system, based on the proposed above concept to treat at least 20 L/day.

The term "Watergy" was coined by the Alliance to Save Energy to describe the strong link between water and energy in municipal water systems. The Watergy approach helps cities realize significant energy, water and monetary savings through technical and managerial improvements in water supply and wastewater treatment systems, creating efficiencies that provide consumers with quality service with a minimum of water and energy. Efficiency in the water sector involves both the end use of water - such as efficient toilets, low-flow showerheads and reducing peak demand - as well as efficiencies in the supply of water. This paper focuses on the water supply system itself since in many cities most of the inefficiencies occur before the water even reaches the end user. Watergy principles have been applied in numerous cities around the world, demonstrating that water efficiency measures repay themselves quickly and yield many rewards: improvements in water service, immediate increased water delivery, reduced water and energy consumption, and more revenue for system upgrades and new customer connections. Opportunities abound throughout all stages of a water supply system. The most promising areas for intervention within water supply systems are: (i) improving the pumping system, (i) managing leaks, (iii) automating system operations, and (iv) regular monitoring (preferably with rigorous metering of end use). These improvements often pay for themselves in months, most do so within a year, and almost all recover their costs within three years. The pumping system is all important, since every liter of water that passes through the system represents a significant energy cost, a cost that is magnified by every liter lost to leaks. Pumping improvements range from lower cost measures like soft starters for motors, trimming impellers (when pumps are over-sized) and re-winding motors, to higher cost measures like replacing inefficient pumps with efficient ones and installing variable speed drives. System automation saves water, energy and operation costs, improves service, and lengthens equipment life. Automation handles operational functions in real time in response to changing situations. Examples are optimizing pressure in the network, triggering alarms in case of emergency, and turning off pumps. Regular monitoring of the system components, operations, and performance is essential targets. in order to track performance and evaluate it against a set of benchmarks and Incorporated as part of the larger O&M protocol, monitoring is a no- or low-cost efficiency enhancement within reach of all utility budgets. Effective management of leaks can save enormous quantities of water and energy. Leakage rates can be lowered dramatically with automated controls that reduce pressure in the network, especially at night. Pressure management is generally more cost-effective than expensive repairs to numerous leaks in buried pipes. This paper provides a comprehensive overview—suitable to all technical levels—to introduce the reader to the approaches and benefits of Watergy. It is intended for a wide audience ranging from municipal and water utility decision makers, to funding organizations, to technical utility staff who want a solid understanding of what a water efficiency program entails without a high level of technical detail.

Treated municipal wastewater may contain pathogenous micro-organisms and persistent trace organics leading to problems when being discharged into the surface waters. The investigations of the research project PILOTOX aimed at their elimination from treated municipal wastewater through subsequent oxidation by ozone. For this purpose, the TU Berlin (department of Water Quality Control) in cooperation with the Berliner Wasserbetriebe at the WWTP Berlin-Ruhleben, carried out several tests with a pilot plant by the company WEDECO aiming at the ozonation of the effluent. The results show that ozonation is a suitable procedure to remove and transform respectively, substantial quantities of the pharmaceutical residues detected in the effluent of the Ruhleben WWTP and, at the same time, to achieve a germ reduction complying with the threshold values stipulated in the European directive on bathing water. It was found that many trace organics such as the anti-epilepticum carbamazepin or the hormone estron can be removed at a very low ozone dosage to below their analytic detection limit. The X-ray contrast media however, turned out to be more resistant: even at a high ozone dosage, their concentrations could be reduced only partially. In this context, the tests detected that through the combination of H2O2 and ozone, an elevated elimination rate for the substances iopamidol and iohexol can be achieved. The elimination of the analysed trace organics correlated with the decrease of the water’s UV activity. Thus, it is advisable to use the rapidly and simply traceable parameter SAK254 as process control parameter to determine the necessary ozone dosage. In addition, it could be proven that ozonation increases the biological degradability of water components. Laboratory test looking at recontamination levels however, indicate that the threshold values stipulated in the EU directive on bathing water will not be exceeded if the ozone-treated effluent is mixed with water originating from the River Spree. A study regarding the water’s acute and chronic toxicity, to its gene toxicity and endocrine impacts, revealed that – compared to the untreated effluent - no eco-toxicological risk potential can be detected in the ozone-treated water samples.The specific treatment cost covering the large-scale application of ozone treatment at the WWTP Ruhleben range between 1,0 cent/m3 and 2,2 cent/m3, of which the investment costs account for a percentage of 20-30 %.

Redox processes during bank filtration were evaluated in Berlin, where bank filtered water is abstracted for drinking water production. The investigations included the mapping of the infiltration zone, a column study and hydrochemical analyses of the groundwater sampled between lake and production well. The organic carbon content increased and the permeability of the lake sediments decreased with distance from the shoreline. The most important changes with regard to the redox state of the infiltrate occurred within the first metre of flow. Infiltration was mostly anoxic, as oxygen was rapidly consumed within the organic rich sediments. The infiltration zone revealed a vertical redox stratification with hydrochemical conditions becoming more reducing with depth rather than with distance from the lake. The redox zones were found to be very narrow below the lake and wider towards the production wells, suggesting that other than differing flow paths, reaeration after infiltration may also occur and possible mechanisms are presented. Redox conditions were influenced by strong annual temperature variations of the surface water affecting the microbial activity. Aerobic infiltration only took place close to the shore in winter.

The frequent occurrence of the cyanobacterial toxin cylindrospermopsin (CYN) in the (sub)-tropics has been largely associated with cyanobacteria of the order Nostocales of tropical origin, in particular Cylindrospermopsis raciborskii. C. raciborskii is currently observed to spread northwards into temperate climatic zones. In addition, further cyanobacteria of the order Nostocales typically inhabiting water bodies in temperate regions are being identified as CYN-producers. Therefore, data on the distribution of CYN in temperate regions are necessary for a first assessment of potential risks due to CYN in water used for drinking and recreation. A total of 127 lakes situated in the northeastern part of Germany were investigated in 2004 for the presence of the toxin CYN and the phytoplankton composition. The toxin could be detected in half of the lakes (n ¼ 63) and in half of 165 samples (n ¼ 88). Concentrations reached up to 73.2 _g CYN/g DW. CYN thus proved more widely distributed than previously demonstrated. The analyses of phytoplankton data suggest Aphanizomenon sp. and Anabaena sp. as important CYN producers in Germany, and confirm recent findings of Aphanizomenon flos-aquae as CYN-producing species frequently inhabiting water bodies in temperate climatic regions. The data shown here suggest that CYN may be an important cyanobacterial toxin in German water bodies and that further data are needed to assess this.

The cyanobacterial toxin cylindrospermopsin (CYN) is widely distributed in German lakes, but volumetric data for risk assessment are lacking and it is unclear which cyanobacterial species produce CYN in Europe. We therefore analyzed CYN concentration and cyanobacterial composition of 21 German lakes in 2005. CYN was detected in 19 lakes (102 of 115 samples). In total, 45 samples contained particulate CYN only, and 57 contained both dissolved and particulate CYN. The concentrations were 0.002–0.484 mgL-1 for particulate CYN and 0.08–11.75 mgL-1 for dissolved CYN with a maximum of 12.1 mgL-1 total CYN. A drinking-water guideline value of 1 mgL-1 proposed by Humpage and Falconer [2003. Oral toxicity of the cyanobacterial toxin CYN in male Swiss albino mice: determination of no observed adverse effect level for deriving a drinking water guideline value. Environ. Toxicol. 18, 94–103] was exceeded in 18 samples from eight lakes due to high concentrations of dissolved CYN. CYN occurrence in the German lakes could not be ascribed to the three known CYN-producing species Cylindrospermopsis raciborskii, Anabaena bergii and Aphanizomenon flos-aquae, which were detected in some lakes in low abundances. The highest correlation coefficients were observed between particulate CYN and the native Aphanizomenon gracile. It occurred in 98 CYN-positive samples, was the most abundant Nostocales and was the only Nostocales in five samples. This indicates that A. gracile is a potential CYN producer in German lakes.

Cylindrospermopsis raciborskii, an invasive freshwater cyanobacterium, originated from the tropics but has spread to temperate zones over the last few decades. Its northernmost populations in Europe occur in North German lakes. How such dramatic changes in its biogeography are possible and how its population dynamics in the newly invaded habitats are regulated are still unexplained. We therefore conducted a long-term (1993–2005) study of two German lakes to elucidate the mechanisms behind C. raciborskii population dynamics and to identify the abiotic constraints on its development. Our data revealed that pelagic populations of C. raciborskii thrived for three months during the summer, contributing up to 23% of the total cyanobacteria biovolume. Population sizes varied greatly between years without exhibiting any distinct long-term trends. In the annual lifecycle, C. raciborskii filaments emerged in the pelagic habitat when the temperature rose above 15–17 C. At that time, mean photosynthetically active radiation in the mixed water column (Imix) overstepped its maximum. Rates of population net increase were highest at the beginning of the season (0.15– 0.28 day–1), declined continuously over time, and were significantly positively correlated with Imix. This indicates that the onset of the pelagic population is temperaturemediated and that Imix controls its growth. Since Imix peaks before the population onset, the time of germination is of crucial importance for successful development. To test this hypothesis, we designed a model to simulate pelagic population size, starting at different dates in the annual cycle. Moving the population onset forward by 30 days resulted in a doubling of the population size. We therefore conclude that an earlier rise in water temperature associated with climate change has promoted the spread of C. raciborskii to the temperate zone. Earlier warming permits earlier germination, thereby shifting the pelagic populations to a phase with higher Imix, which advances growth and the population establishment.

The paper describes the planning process for the pilot implementation of a decision support system (dss) for global control of sewage pump stations in Berlin, which is going to be realised by the end of 2006. The objective of the control concept is to systematically manage in-pipe storage capacities in order to reduce cso. The paper presents the preliminary assessment of the system’s control potential based upon the analysis of operational figures and numerical simulations. Furthermore, the structure of the decision support systems procedure is illustrated.