Systems Analysis of Zaragoza Urban Water - SWITCH - Managing ...

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Systems Analysis of Zaragoza UWS Guillermo Penagos f. Skilled and sufficient staff: to operate and maintain the system. But also personal with knowledge on microbiology, chemistry and ecology. Gender diversity is also required. g. Social dimension: the service should be socially and culturally acceptable h. Public awareness: on sustainable behavior This work has quantitatively analyzed the aspects a. and d. of Zaragoza UWS. One important aspect that has been neglected in this research is the water infrastructure, which is determinant for sustainable urban planning in terms of scale, use of space and longevity (Lundin & Morrison, 2002). Nevertheless for the SWITCH project it might be interesting to evaluate, for instance, the environmental impacts and the long time perspective of the ongoing projects on infrastructure upgrading in Zaragoza. 5.2 LCA as a tool for Sustainability assessment The methodology used for this research is based on the LCA methodology, that is being extensively used to assess environmental sustainability of Urban Water Systems and it has proven to be very useful. However it has got some important drawbacks as well. For instance some authors criticize the fact that it overlooks important geographic variations such as the resilience of receiving water, also some qualitative aspects, such as sludge quality or ecosystem health are difficult to assess with LCA. Finally, water consumption is not incorporated in the analysis, therefore, it can be considered as a useful tool, but complementary information should also be included for a more complete approach to evaluate urban sustainability (Lundin, 1999) The present work evaluated the sustainability aspects of water extraction, but also resource consumption and pollution impacts. Such values are presented as indicators for environmental sustainability with the main purpose of providing comprehensive and quantitative information to decision makers in Zaragoza. 5.3 Sustainability Indicators There are many indicators that are currently being used by water organizations around the world to assess their performance and they are suggested to be sustainability indicators but only few actually are (Lundin and Morrison, 2002). For instance percentages of pollution removal at WWT facilities are often suggested as sustainability indicators but those provide information only about the performance of existing end-of-pipe technologies. Percentages of removal can for instance remain 60
Systems Analysis of Zaragoza UWS Guillermo Penagos the same over time while both pollution concentrations and pollution loads to the environment are actually increasing. Additionally, higher effectiveness may decrease the efficiency, since more resources are required per amount of pollutant that is removed. In this sense, total loads are more useful indicators, since they can actually reflect, not just the technical performance of WWT, but also whether pollution sources within the city are controlled. An example of this is the management of heavy metals and other toxic substances by Local Agenda 21 Office in Zaragoza. Being aware that the existing WWTPs in the city are unable to treat such substances, they are controlling industrial activities to prevent those to enter the sewer system. Such control on industrial activities will be reflected in the total heavy metal loads, but it won’t be quantified by the percentage removal at all. In this report the definition of sustainability indicator from Lundin (1999) is used as reference point: “A sustainability indicator should link (or at least balance) different areas of society e.g. life styles, economy, resource use and environmental problems or relate to a sustainability target. Consequently, an indicator of environmental sustainability can be defined as an environmental performance indicator (EPI) where the target reflects a sustainable situation. It should ideally provide an early warning for potential problems, being understandable and usable, within the urban water sector and/or for the public and information for calculated should be available”. Basically most data presented here more or less fulfill this definition and is therefore are suggested to continue being used as part a pool of sustainability indicators Zaragoza Urban Water System. Evidently these indicators relate only with the environmental dimension of sustainability. The social and economic dimensions will require different ones. Also additional indicators would be necessary to fully evaluate the environmental performance of the system. A list of indicators derived from this work is provided next: 1. Water withdrawal 2. Water consumption 3. Energy consumption 4. Chemical product consumption 5. CO 2 direct and indirect emissions 6. Pollution loads to the Ebro River (TP, TN, BOD, COD and Heavy Metals) 7. Percentage of Impact upon the river by target pollutants (TP, TN, BOD, COD and Heavy Metals) 61
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