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.

The goal of this study is the identification of ecological advantages and disadvantages of alternative sanitation systems in comparison to conventional wastewater treatment. The methodology of Life Cycle Assessment (LCA) is adopted as an evaluation tool for the ecological assessment of various sanitation scenarios for a hypothetical middle-sized settlement in Germany (ca 5000 inhabitants). The scenarios include a reference system with conventional drainage and treatment in an activated sludge plant with anaerobic sludge digestion and sewage gas production. In the alternative scenarios, urine is source-separated in the toilet, collected and applied as fertilizer. Faeces are either collected by gravity drainage and composted together with biowaste or collected by a vacuum system and co-digested with biowaste to gain biogas for energy production. The remaining greywater is treated in a soil filter or in a technical plant (Sequencing batch reactor). All relevant processes of the investigated scenarios are modelled in detail for the Life Cycle Inventory, based on data from pilot plants and literature. This implies the processing of the different waste fractions, transport and energy supply, mineral fertilizer substitution, and sludge incineration. Beside the operational expenditures, the construction phase is included with material and energy demands. The resulting substance flow model is evaluated with a set of environmental indicators relating to the demand of energy, non-renewable resources, climate change, eutrophication, acidification, and various toxicity potentials. As a result, the alternative scenarios cause less environmental burden in almost all impact categories. The source-separation of human excreta disburdens the wastewater treatment process and lowers nutrient emissions into surface waters. The secondary fertilizer from urine and faeces has lower heavy metal content than an average mineral fertilizer. Depending on the system configuration, alternative sanitation systems can have a lower demand for fossil fuels and subsequently cause fewer emissions of climate-active gases. Only the increased emission of acidifying gases represents a considerable drawback compared to the conventional system. A normalisation of all indicators to the average environmental burden of a single person in Germany reveals that the decisive categories for the overall comparison are related to eutrophication, acidification, and terrestrial ecotoxicity. Energy-related indicators have a smaller contribution, but they can be important in terms of world-wide scarce fossil resources and climate change. The advantages of alternative sanitation systems can only be realized if the secondary functions of mineral fertilizer substitution and energy supply are fully utilized. Important key parameters for future LCA studies of alternative sanitation systems are identified, which may simplify the data acquisition. The construction phase has only a minor relevance for the ecological assessment and may therefore be neglected in future studies. In all, the data quality of this LCA study can be further improved, because many processes of alternative systems have not yet been investigated or realized in full-scale. Hence, the development of a universal decision support method could not be realized in a reasonable way due to the lack of adequate long-term process data and the high influence of case-specific boundary conditions on the technical implementation. However, this LCA study gives a first assessment of potential ecological benefits and drawbacks of alternative sanitation systems.

The main goal of this project is to develop new sustainable sanitation concepts which have significant advantages in relation to ecological as well as to economical aspects compared to the conventional systems (end-of-pipe-system). After successful project completion the new sanitation concepts should be used in Berlin areas, where sewer systems are not installed and these concepts are appropriate, as well as other locations (national and international). The technical management of the project has been achieved as foreseen, but the administrative project manger has changed in July 2005 since the head of the Berlin Centre of Competence for Water has changed. All technical equipments, besides of the bio-gas plant, are realised. The bio-gas plant will be installed about the end of 2005. In contrary to the EU-proposal the concept with vacuum separation toilets has been installed for technical reasons in the office building instead in the apartment house. Before installing of these toilets gravity separation toilets have been operated for 1 ½ years. Furthermore not in 15 but in 10 flats of the apartment house was it possible to install gravity separation toilets. The addition tasks Life-Cycle-Assessment (Task 5), Industrial style urine treatment for utilization (Task 7) and Fertiliser usage (Task 8) undertaken by different Universities are in the works. The users accept the separation toilets in general, but more the gravity than the vacuum separation toilets. Both have to be improved, especially the flush. The worse assessment for the vacuum separation toilets was expected since they are altered gravity separation toilets. An optimised vacuum separation toilet is not available on the market at present. The results from the faeces separator show that far the most solids can be retained in the filter bags, but there is still a high solids-concentration in the filtrate. For huge settlements a different, continuously working separator is necessary. Due to the high solid concentration in the faecal filtrate the soil filter as a pre-treatment step was blocked very soon and went out of operation. With the 2-chamber septic tank for greywater and faecal filtrate treatment an effluent quality could be obtained which does not lead to clogging of the downstream constructed wetland. The results of the constructed wetland are as expected. From the work of Task 5 and the experiments of Task 7 no reliable results are available until now. The experiments of Task 8 show that the fertilising results from the urine are similar with those from mineral fertilisers. Until the end of the project the different tasks will continue. The digestion of the faeces from the vacuum separation toilets with the bio-gas plant will start in January 2006. In relation to the financial issues 790,482 € (51 %) of the total eligible costs of 1,552,116 € and 1,230,640 € (55 %) of the total real costs of 2,223,474 € respectively have been spent until now. Herewith, the 30 % threshold of the total real costs is transcended.

The main goal of this project is to develop new sustainable sanitation concepts which have significant advantages in relation to ecological as well as to economical aspects compared to the conventional systems (end-of-pipe-system). After successful project completion, the new sanitation concept should be used in Berlin areas, where sewer systems are not installed, as well as other locations (national and international). The management of the project has been achieved as foreseen. No relevant modifications have been necessary. In relation to the technical development all eight tasks have been started. Some later than scheduled but this does not endanger the goal and end date of the project. The first results from the greywater treatment with the constructed wetland show that the effluent quality is comparable to the wastewater treatment plants of Berlin In contrary to the proposal the new sanitation concept using vacuum separation toilets will be realised in the office building instead of apartment building. Furthermore not fifteen but ten flats are taken into account for the project and all bathrooms will be completely retrofitted instead of installation of new toilet systems only. Due to the fact that external assistance for designing is necessary the costs for external assistance is higher than planned. The precise figure will be available earliest at the end of 2004. All modifications do not endanger the goal of the project. For the information and discussion with the national and international public and colleagues about this project many presentations, publications and visits of the demonstration project have been undertaken and organised, respectively. The envisioned progress up to the interim report in March 2005 will be the realisation and start up of operation of the sanitation concept in the apartment building, exchange of the gravity separation toilets against vacuum separation toilets in the office building, designing, installation and operation of the digester. Furthermore all work from subcontractors (Life-Cycle-Assessment, Urine treatment, Fertiliser usage) will continue. Different international presentations are also foreseen. In relation to the financial issues 325.906 € (21 %) of the total eligible costs of 1.552.116 € and 511.515 € (23 %) of the total real costs of 2.223.474 €, respectively, have been spent until now. The 30 % threshold of the total real costs will be achieved presumably at the end of 2004.