MBR-technology is able to fulfil similar or even higher standard for nutrients removal than conventional activated sludge processes. This paper presents the optimisation of the membrane bioreactor technology, together with a low pressure sewer, to equip a remote and yet unsewered area of Berlin requiring high quality wastewater treatment. The hydraulic flow pattern of the entire system has to be studied carefully due to the small collection system (no time delay between wastewater discharge and treatment to minimise the daily profile). The pollutant concentrations in the wastewater exhibit also stronger variations. In order to flatten out the hydraulic and load profile, and therefore to reduce the size of the biological reactor and the membrane surface, an buffer tank was installed before the MBR-plant. A full analysis of the influent hydraulic flow and wastewater characterisation is provided for the demonstration MBR-plant.

For small membrane bioreactor (MBR) plants, in order to save investment for infrastructure, it could be beneficial not to withdraw excess sludge on a daily basis, but to store it in the biological reactor and only withdraw it every 2 to 4 weeks. This study aimed at investigating the effect of such an excess sludge removal strategy on the performance of an MBR plant in terms of permeate quality, nutrients removal rates and fouling. An MBR pilot plant, fed with domestic waste water from a remote area, was operated with enhanced biological phosphorus removal and post-denitrification without carbon dosing. 50% of the reactor volume was withdrawn when around 13 g l-1 TS was reached in the membrane reactor. This sludge removal strategy did not lead to failure of neither the biological phosphorus removal, nor the post-denitrification. Higher specific denitrification rates (DNR) were observed during higher organic loading of the anaerobic zone. The average DNR at 20°C was 1.5 mgN(gVSS h)-1. Nitrification was influenced by the discontinuous excess sludge removal. During that period the nitrification rate varied in a wide range between 1.8 and 5 mgN(gVSS h)-1, with a trend to lower rates right after a sludge removal. Fouling was not effected by the excess sludge removal strategy. For both withdrawal strategies the fouling rate was around 5*1010(md)-1. The EPS concentration did not affect the fouling behaviour.

Zentrale, konventionelle Wasserver- und Abwasserentsorgungskonzepte, in industrialisierten Ländern seit Jahrzehnten entwickelt und angewandt, sind aufgrund hoher Kosten, hohen Wasserverbrauches und geringer Wiederverwendung von Nährstoffen nicht hinreichend nachhaltig, insbesondere nicht für den Einsatz in Entwicklungsländer. Zielvorstellungen der nachhaltigen Konzepte sind eine weitgehende Wiederverwendung des gereinigten Abwassers, sowie der Nährstoffe, verbunden mit einem geringeren Energiebedarf bzw. einer Produktion von Energie. Alternative Konzepte und Techniken stehen bereits seit einiger Zeit zur Verfügung und werden auch angewendet, dennoch sind weitere Entwicklungen und Plausibilitätsprüfungen erforderlich. Aus diesem Grund hat das Kompetenzzentrum Wasser Berlin (KWB) zusammen mit den Berliner Wasserbetrieben (BWB) und Veolia Water ein entsprechendes EUDemonstrationsprojekt (Sanitation Concepts for Separate Treatment (SCST)) durchgeführt. Hierbei wurden zwei unterschiedliche Sanitärkonzepte in Gebäuden der BWB auf dem Gelände des Klärwerks Stahnsdorf erprobt. Ziel dieses Projektes war es zu erproben, ob diese neuen Sanitärkonzepte sowohl in ökologischer als auch in ökonomischer Hinsicht signifikante Vorteile gegenüber den konventionellen Sanitärsystemen mit Schwemmkanalistation und Kläranlage (end-ofpipe- system) bieten.

Within the EU-funded demonstration project 'Sanitation Concepts for the Separate Treatment of Urine, Faeces and Greyweater' (SCST), initiated, financed, and coordinated by Berlin Centre of Competence for Water (Kompetenzzentrum Wasser Berlin), Berliner Wasserbetriebe and Veolia Water the Institute of Wastewater Management and Water Protection of Hamburg University of Technology (TUHH) investigated processes for resource recovery and elimination of pharmaceutical residues from separate collected human urine. The main processes for resource recovery were steam stripping for nitrogen extraction and vacuum evaporation for volume reduction and obtaining highly concentrated nutrient solutions. The processes precipitation, crystallization, and adsorption, were used for nutrient recovery as follow-up techniques. The effect of steam stripping and evaporation on the reduction of PhaR was investigated, as well as the effect of the additional processes UVCradiation, ozonation.

The discussion of sanitation concept differing from the conventional one, i.e. systems with one sewer system and a central wastewater treatment station, is an ongoing increasing process. These new sanitation concepts have the target of saving and reuse the water as well as the nutrients. The approach of being a more appropriate technology can be demonstrated by life cycle analysis (Peter-Fröhlich et al, 2007). Due to the lack of implementation and long time experiences detailed cost comparison are not available yet. First estimations have been done and have shown a tendency, but detailed investigations have been missing. The results of the SCST-project, which represents an experience of four years implementation and operation of a new sanitation concept, will be used for a cost comparison of different sanitation systems. It is obvious that the prerequisite for a successful implementation beside the technical applicability is the demonstration of the systems benefits. These new sanitation systems will receive only acceptance, when economical benefits or other significant benefits will support their introduction. Therefore studies of cost comparisons are necessary and an important issue.

The recycling of plant-nutrients as nitrogen, potassium and phosphorus from human nutrition is considered to be a preposition towards sustainable agriculture. Commonly, human excreta are collected together with waste water and other liquid wastes from households and small industries. During the treatment in central sewage-works the valuable nutrients cannot be separated from potentially harmful substances such as heavy metals. Therefore, the application of sewage-sludge on agricultural fields is strongly limited. Today, in Germany a major amount of sewage sludge is burned in waste incineration plants. This means a dissemination of phosphorus, potassium and nitrogen into the atmosphere. Phosphorus and potassium fertilisers are extracted in mines and as such non-renewable. A shortage of phosphorus to be used as fertiliser is expected to arise within the next 80 years (STEEN, 1998). Alternative Sanitation Concepts such as the separate collection and treatment of urine and faeces prevent the contamination of the plant nutrients with potentially harmful or unwanted substances from other liquid wastes. The main feature of this concept is the use of a separation toilet. It can be used in the same way as any other common flushing-toilet but has a special valve for separate urine collection. The urine can easily be stored in containers e.g. in the basement of a house and used as fertiliser. A composting process ensures hygienisation of the solid faeces separated from flushing water. Due to its low content of nitrogen all remaining waste water can be treated in a constructed wetland. The studies introduced followingly were carried out within the scope of the SCST (Sanitation System of Separate Treatment) research project. This EU-Life demonstration project is a result of the cooperation of the KompetenzZentrum Wasser Berlin, Berliner Wasserbetriebe, Veolia Water and Anjou Recherche. It contains a setup of a complete Alternative Sanitation system including the conversion of 10 private households and two office-buildings as well as a biogasplant and a constructed wetland in Berlin-Stahnsdorf. It was the aim of the SCST-project to demonstrate the feasibility of an alternative sanitation system working with separation toilets. Apart from the technical questions to be answered it was necessary to know how urine and faeces are to be used in agriculture. The following four questions point out the aspects which needed to be investigated in detail: (i) How are the fertilising effects of urine und faeces compared to conventional mineral fertiliser? (ii) What impact has urine to soil organisms? (iii) How much gaseous nitrogen is lost after application? (iv) Would farmers and consumers accept urine as fertiliser? In this report you will find the four mentioned aspects investigated. This was done by carrying out laboratory or field experiments as well as acceptance SCST Final Report Task 8 – Fertiliser usage – Muskolus, Humboldt University of Berlin - 4 - studies for each of them accordingly. You will find a detailed description of the methods and materials used as well as the results and statistical evaluation as appropriate. Regardless of the advantages possibly reached by a treatment of urine in the presented studies it was assumed that pure urine was used. It is still not known what kind of processing is suitable to reduce the water content of urine or any unwanted substances and whether the energy input during the treatment is justifiable or not. However, some results of the studies followingly presented may change if treated urine instead of pure urine was used.

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.