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.

Dieser Leitfaden wurde im Rahmen des Forschungs- und Entwicklungsprojektes „Getrennte Erfassung von jodorganischen Röntgenkontrastmitteln in Krankenhäusern“ der Kompetenzzentrum Wasser Berlin gGmbH erstellt. Er soll dazu dienen Ihnen einen kurzen Überblick zu geben, wie und warum die getrennte Sammlung von Urin der Patienten, die mit jodorganischen Röntgenkontrastmitteln untersucht werden, in Krankenhäusern durchgeführt werden könnte. Das Projekt wurde in zwei Phasen in Zusammenarbeit mit zwei Berliner Krankenhäusern, einem Universitäts-Klinikum und einem Krankenhaus der Grundversorgung, realisiert, die beispielhaft für das Krankenhauswesen in Deutschland stehen. Die 1. Phase, eine Machbarkeitsstudie, dauerte von April 2004 bis April 2005 und bildete die Grundlage für die 2. praktische Projektphase, die bis zum Dezember 2005 durchgeführt wurde. In der 2. Projektphase wurde das dezentrale Erfassungskonzept mit mobilen Urinbehältern (siehe Bild 1), entsprechend der Machbarkeitsstudie, im Zeitraum von 20 Wochen auf jeweils einer Krankenhausstation getestet, um die Röntgenkontrastmittel an der Quelle zurückzuhalten und nicht ins Abwasser gelangen zu lassen (Pineau et al., 2005; Pineau und Heinzmann, 2005; Schuster et al., 2006).

The ENREM project aims at demonstrating a novel wastewater treatment process based on the technology of membrane bioreactor (MBR), set up in a configuration to enable enhanced biological elimination of nutrients. A new plant, and the related sewer system, was built in a unsewered periurban area of Berlin. The plant is to be operated over more than one year, and the process to be optimised. Performances and costs of the treatment system will be then assessed for the size 250 – 10,000pe, corresponding to semi-central schemes. The plant was started on 28 February 2006 with 8 month delay on the program identified in the LIFE proposal. As a consequence, a project extension request of 8 months will be lodged, in order to match the initial duration of 18 months for the optimisation, evaluation and dissemination phase. This delay incidentally caused also a 6 month delay for the preparation of this Interim Report. Despite these aspects, the management of the project has been achieved according to the organisation identified in the LIFE proposal. Annex 7.1 presents and discusses the key deliverables and milestones depending on the LIFE proposal and the current status. In relation to the technical content, Task 2 “Site and process definition” and Task 4 “Detailed design” were completed early 2005. Task 3 “Preliminary testing on representative site” was completed in September 2005 and enabled to validate the design, operation and start-up criteria of the MBR demonstration plant. The public tenders for the construction of the sewer network and the MBR container unit occurred during the first semester of 2005, and the construction of the scheme was completed by end 2006. In parallel, the required legal permits were acquired (for plant construction & operation, water discharge), as well as the parcel hosting the treatment unit. A relationship with the inhabitants of Margaretenhöhe was maintained in order to ensure a smooth construction phase, and a quick connection to the new sewer system. The dissemination activities covered several communication vectors (Tri-lingual website www.kompetenz-wasser.de, press-release and articles and bi-lingual KWB Newsletter, local press, scientific press, plant visits and inauguration, communication material etc). The project results will be widely communicated in the national and international medien, and a final project workshop will be organised in June 2007. The main task in 2006 will be the operation, optimisation and technical / economical evaluation of the low sewer system and the MBR demonstration plant. So far, the budget is generally in line with the expectations, or slightly below. The project finances allow the project extension of 8 months, required to achieve all announced technical outcomes of the project. After the 8 month extension the final project budget is expected to remain about 20% below the planned proposal, i.e. approx. € 600,000 savings on the total budget should be recorded, corresponding to a subvention reduction of approx. € 100,000 (also close to 20% reduction).

The development of the integrated control of sewage network and wastewater treatment plant has progressed during the last decade. Nevertheless, an operational implementation of the concepts for huge, complex systems has hardly been realised. That was an obvious reason to initiate the project "Integrated Sewage Management (ISM)". The ISM project aimed at the development of strategies for an integrated management of the Berlin sewage system consisting of sewer networks (both, combined and separate system), pump stations, pressure mains and wwtp. For these purposes a numerical model of the collection system has been built up. Those catchments have been chosen that have a significant quantity of wastewater and are connected to at least one of the three main wastewater treatment plants of Berlin (Ruhleben, Waßmannsdorf and Schönerlinde). To enable an evaluation of total emissions it was necessary to incorporate not only catchment area and collection system but also the wwtp into the model. Furthermore, the Berlin specific transport of wastewater through pressure mains had to be considered. Both, advective pollutant transport and the limiting pressure situation had to be taken into account. An integrated model of collection system, pressure mains and wwtp has been set up for the catchment of wwtp Ruhleben for the study of a global control concept. Those processes that were of particular importance for the control concepts or had a significant influence on the criteria (derived from the objectives) had to be simulated adequately. Hence, for the Berlin model the main attention was paid to an accurate reproduction of in-pipe storage activation and the transport of wastewater through the pressure pipes. A sufficient set of data was available to model the system structure. For process parameter estimation the necessary information was taken from the operational SCADA system. Some gaps in the data could be closed by additional measurement campaigns (Bln VII, 2001; Bln X, 2002; Heiligensee, 2003). For modelling the collection system the dynamic flow routing model InfoWorks CS of Wallingford Software Limited has been chosen due to its user-friendliness (window navigation, GIS) and comprehensiveness (pollutant load calculation, long-time simulation, spatial rainfall distribution, rtc module). A suitable approach to the simulation of the Berlin pressure mains was found to be based on EPANET 2 of the U.S. Environmental Protection Agency. The software SIMBA® 5 of ifak System GmbH has been used to simulate the dynamic treatment processes. For the activated sludge conversion part the Activated Sludge Model No. 1 (ASM 1) has been used. The three models have been coupled in sequence on the basis of simple input and output files. Further on, in the framework of three sub studies the ISM model has been applied to operational questions. The applicability of the ISM model for the assessment of the impact of the NPA control on the wwtp was tested. NPA stands for “new pump automatic (Neue Pumpen Automatik)” and signifies a control concept that is implemented in the framework of the LISA project (BWB). The inflow to wwtp Schönerlinde has been simulated for one rain event and the NPA control of the pump stations could be simulated well on the basis of the InfoWorks rtc module. Furthermore, the ISM model has been applied to evaluate a concept for a level dependant real-time control (Pegelgesteuerte Förderstromregelung) of sewage pump stations. The idea of the concept was to build an easy function that allowed continuously varying the pumpage and implicitly managing available inline storage capacities within the trunk sewers. The objective was to smooth the delivery towards the treatment plant to avoid peak loads. The evaluation showed that it is possible to manage available inline storage volume by applying the control function. But only if there is an adequate retention volume of around 60.0 m³/ha Aimp or more a significant improvement of the flow characteristic towards the wwtp is possible. Consequently, in Berlin only two catchments have the potential for the introduced control concept (Charlottenburg III und Ruhleben). Finally, the effects and the benefit from global pump station control in comparison to local control have been studied on the basis of the integrated model. The assessment of the Berlin drainage system that was carried out before arrived at the conclusion that there is a high potential for the control of the total system. The positive rating can partly be ascribed to the high storage volume that can be activated within the trunk sewers and the high number of pump stations that are used as actuators. However, this potential is already used by locally controlling the pump stations and storing sewage in the collectors. The potential of a global control of sewage pump stations arises from the non-uniform distribution of rainfall and the non-uniform distribution of storage volumes over the system. Those conditions usually lead to a non-uniform utilisation of storage capacities and further on to sewer overflows that cannot be balanced by local control. A look on the simulated total emissions showed that concerning discharged quantities the load from the wwtp is highly dominant, since most of the time (under dry weather conditions) wwtp effluents are the only impact on the receiving water. Furthermore, the global control concept only works during rain situation and does not have an influence on dry weather effluents. Consequently, the influence of global control on yearly total emissions is marginal. Nevertheless, it could be shown that global control can avoid peak load situations at the inflow to the wwtp and consequently reduce peak loads in the effluent. The control concepts had a significant influence on the emissions from combined sewer overflows. The reduction of sewer overflows plays a prominent role since they present a highly dynamic impact on the water body. The simulations showed that on average during periods of cso 2.5 t COD/h enter the receiving water. Compared to that load the continuous impact from the wwtp effluent was only 0.4 t COD/h. Moreover, due to the high fraction of biodegradable organic substrate the impact from combined sewer overflows is of special relevance. In contrary to the refractory COD from wwtp effluents, 60 % of the COD from combined sewer overflows are biodegradable leading to extreme oxygen depletion within the receiving water. It could be shown that under current conditions at the wwtp (rain weather capacity of wwtp Ruhleben = 6700 l/s) a local control (= local automation) of the pump stations has an adverse effect on the performance of the sewage system. In contrary to an optimum coordination of the pump stations local control leads to an overloading of the wwtp and an increase of emissions from combined sewer overflows by 9 % (volume), 15 % (COD) and 20 % (TKN). Due to that reason the current operation provides for manual interventions in case of rain events to coordinate the delivery of the pump stations. This necessity will persist under the LISA automation. Assuming a future upgrade of wwtp Ruhleben and an increase in rain weather capacity up to 7650 l/s, global pump station control will result in cso emissions that are 19 % (volume), 20 % (COD) and 25 % (TKN) below that under local control (= local automation). The major deliverable of the ISM project is the model for the Berlin collection system (18 combined and 29 separate sewer systems that are connected to the three main wastewater treatment plants Ruhleben, Waßmannsdorf and Schönerlinde). The further application and maintenance of the sewer model will take place at BWB, department NA-G. The scope of studies that will be supported by the model covers operational planning as well as general, conceptual and investment planning (storage optimisation, problem of parasite water). Concerning the implementation of the global control concept that has been developed in the framework of the ISM project first tests shall be carried out in 2006 and 2007. Therefore, the follow-up project EVA (Entscheidungshilfesystem zur Verbundsteuerung von Abwasserpumpwerken / Decision support system for global control of sewage pump stations) was planned at KWB to enable support and a further cooperation between KWB and BWB. The algorithm has to be adapted to the operational and technical boundary conditions and a detailed practical planning in terms of control engineering has to be carried out. The main prerequisite for an implementation of the introduced control concept is the technical ability of the pump stations to increase delivery beyond the value of 2 * Qd,16. Simultaneously, an authorisation is necessary to introduce a flexible regulation of the pump station’s rain weather delivery off the value of 2 * Qd,16 as demanded nowadays by the Berlin water authority. If the necessary data is available (usually given by the existing scada system of BWB) and if the used pumps can be controlled according to the above-stated technical requirements, thestudied control concept can be implemented without any further constructional investment.