2nd international symposium on ecological sanitation, april 2003 Session H Decision making tools Chairpersons Jes La Cour Jansen (Lund Institute of Technology, Sweden) Ralf Otterpohl (Technical University Hamburg-Harburg, Germany) Lectures Ecological assessment of ecosan concepts and conventional waste water systems * Ralf Mühleck, Andreas Grangler, Martin Jekel (Technical University Berlin, Gemany) The phosphorus calculator: A planning tool for closing nutrient cycles in urban eco -systems* Bekithemba Gumbo (University of Zimbabwe, Zimbabwe), Hubert Savenije, Peter Keldermann Assessment method for evaluating existing and alternative measures of urban water manage- ment* Dongbin Huang, Roland Schertenleib, Hansruedi Siegrist, Tove A. Larsen, Willi Gujer (EAWAG, Switzer- land) Options for sustainable urban water infrastructure systems: Results of the AKWA 2100 project Harald Hiessl, Dominik Toussaint (Fraunhofer Institute, Germany) Comparison of resource efficiency of systems for the management of toilet waste and organic household waste* Daniel Hellström, Andreas Baky, Ola Palm, Ulf Jeppson, Helena Palmquist (Stockholm Vatten, Sweden) The Swedish Urban Water programme Per-Arne Malmqvist (Chalmers University of Technology, Sweden) Model city urban enclave in urban water - does ecosan improve sustainability of the sewage system? Håkan Jönsson (Swedish University of Agricultural Sciences, Sweden) Comparison of sanitation latrines used in China Li Xianghong (Guangxi Medical University, China), Lin Jiang Overview on worldwide ecosan - concepts and strategies Heinz-Peter Mang, Christine Werner, Susanne Kimmich (GTZ, Germany) Session H Data sheets on ecosan technologies and projects - an information management tool in process Susanne Kimmich, Christine Werner, Heinz-Peter Mang (GTZ, Germany) Oral poster presentations Linking urban agriculture and environmental sanitation Dionys Forster, Roland Schertenleib, Hasan Belevi (EAWAG/SANDEC, Switzerland) Potentials for greywater treatment and reuse in rural areas Elke Müllegger, Günter Langergraber, Helmut Jung, Markus Starkl, Johannes Laber (University of Natural Resources and Applied Life Sciences Vienna, Austria) *This paper has been peer reviewed by the symposium scientific committee 731 2nd international symposium on ecological sanitation, april 2003 Selection of DESAR system for unsewered settlement in almost completely sewered society * Wendy Sanders, Katarzyna Kujawa-Roeleveld, Marianneke Wiegerinck, Maaike Poppema, Eligius Hendrix, Grietje Zeeman (Wageningen University, The Netherlands) The decentralization of sewage purification from the perspective of open space and urban pla n- ning* Gudrun Beneke, Hille v. Seggern (University of Hannover, Germany) Sustainable treatment of waste(water) in rural-areas of Egypt* Tarek Elmitwalli (Benha High Institute of Technology, Egypt), Harmed Elmashad, Adriaan Mels, Grietje Zeeman Multi criteria decision aid in sustainable urban water management Denis van Moeffaert (Scandiaconsult Sweden) Poster presentations Assessing the sustainability of domestic water systems, including water use and wastewater treatment Annelies J. Balkema, Heinz A. Preisig, Ralf Otterpohl, Fred. J. D. Lambert (Eindhoven University of Technology, The Netherlands) Session H *This paper has been peer reviewed by the symposium scientific committee 732 2nd international symposium on ecological sanitation, april 2003 Ecological assessment of ecosan concepts and conventional wastewater systems* Ralf Mühleck, Technical University Berlin Andreas Grangler, Institute for Environmental Engineering Martin Jekel Department of Water Quality Control (KF4) Str. d. 17. Juni 135, 10623 Berlin, Germany e-mail: [email protected] e-mail: [email protected] e-mail: [email protected] Keywords Decision support system, indicators, life cycle assessment, material flow analysis, source sepa- ration, wastewater systems Abstract In order to assess the environmental impacts of different water management options in urban areas, a decision support system (DSS) was developed. The DSS is based upon a Material Flow Analysis (MFA) of the technical system and a set of environmental indicators. With the help of this tool, two scenarios for the conventional wastewater treatment and two ecosan sce- narios for the city of Berlin are assessed and discussed. Introduction Traditionally, wastewater systems had been designed and assessed according to their ability to fulfil specific, water-related tasks such as ensuring a reliable urban drainage system or the effi- cient protection of the receiving waters. However, for the development of sustainable wastew a- ter concepts, the prediction of additional environmental impacts, of social and economic aspects must be integrated into the decision-making process. But even an integrated assessment of all the environmental impacts remains a complex task without the support of appropriate methods for the determination and a set of indicators for the quantification of those impacts. Mostly, wastewater treatment plants (WWTPs) have been assessed using MFA (e.g. Dennison 1998, Jeppsson and Hellström, 2002). However, in only a few cases that method has been used for strategic planning or decision-making processes on a local or regional level. Most of Session H the investigations were focused on the comparison of specific technologies and the determina- tion of the best alternative for one single site, not necessarily being the optimal solution for the whole region. Therefore, a methodology for the assessment of water management strategies on a regional level was developed. From that perspective, all the benefits as well as the negative effects of water management strategies may be included in the comparative assessment of di f- ferent alternatives. To measure progress towards sustainability, various indicator concepts for the evaluation and comparison of water systems have been proposed (e.g. Lundin et al., 1999; Balkema et al., 2001; Raval et al., 2001). For the assessment of the ecological aspect of sustainability, the pro- tection of natural resources and the minimization of enviro nmental impacts (e.g. Daly 1990) are two important goals that are reflected in the indicator systems. *This paper has been peer reviewed by the symposium scientific committee Mühleck 733 2nd international symposium on ecological sanitation, april 2003 Methods A generally applicable concept for a DSS was developed, consisting of MFA as a method for the simulation of environmental impacts caused by different water management strategies. Those local, regional and global impacts are quantified with a set of environmental indicators. The assessment of the current wastewater system in Berlin and three alternative scenarios was carried out to demonstrate the concept. Material flow analysis A material flow model for the technical constituents of the drinking water and wastewater sy s- tem in Berlin was used. The model comprises the waterworks, the water distribution system, the sewerage system and the WWTPs (primary system, see fig.1) and is based on data supplied by the Berliner Wasser Betriebe (BWB, Berlin Water Company). In addition, the environmental i m- pacts of relevant processes that are connected to water ma nagement systems (e.g. supply of raw and process materials, sewage sludge disposal) were integrated into the model (extended system, see fig.1). The material flow model was realized with the software UMBERTO â, a widely used tool for environmental management and Life Cycle Assessment (LCA) studies. The model is extended successively to different water treatment technologies (e.g. for drinking water production, wastewater treatment, sewage sludge treatment, storm water management, dece n- tralized sanitation). The input flows and output flows of the system were calculated with that model and transformed into the values for the environmental indicators. production of raw materials generation and supply of electric energy ground- PRIMARY storm water water SYSTEM water - water sewerage households wastewater effluent works distribution system treatment bank source sludge filtration separation Session H fertilizer transport transport production sludge methyl alcohol treatment production solid waste methyl agriculture emissions waste disposal alcohol Figure 1: System boundaries Indicators Appropriate indicators for urban water supply and wastewater systems were to be a reflection of the current ecological problems related to water (OECD, 2000; Walz et al., 1997). In an interdi s- ciplinary research group, the indicators for the assessment of the technical constituents of urban water management listed in tab.1 were developed together with indicators for groundwater, sur- face waters and land use (Weigert and Steinberg, 2002). Some of the indicators were adopted from the impact assessment of LCA (ISO 14040-43). In water management, suitable indicators must reflect specific local (e.g. emissions into surface waters and soil, consumption of local wa- 734 Mühleck 2nd international symposium on ecological sanitation, april 2003 ter resources etc.) and site-dependent environmental problems (Hügel 2000). Moreover, pra g- matic reasons, above all the availability of data, influenced the choice of indicators. So the in- formation from environmental management systems of water companies was used. The famili- arity of decision-makers in water management with parameters that have legislative relevance was also taken into account. Thus, emissions into water were aggregated to the so-called