Systems Analysis of Zaragoza Urban Water - SWITCH - Managing ...
Systems Analysis of Zaragoza Urban Water - SWITCH - Managing ...
Systems Analysis of Zaragoza Urban Water - SWITCH - Managing ...
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<strong>Systems</strong> <strong>Analysis</strong> <strong>of</strong> <strong>Zaragoza</strong> UWS<br />
Guillermo Penagos<br />
interpretation (U.S EPA, 2006; Ayers and Ayers, 2002). For the present work the step 3<br />
was not carried out and interpretation is made from the life cycle inventory.<br />
3.2.1 Developing flow diagram<br />
First step to define system boundaries is developing a flow diagram showing the<br />
processes to be evaluated. In the present work the aim is to analyze all the major<br />
processes for the urban water system: water withdrawal, water treatment and<br />
distribution, water use, wastewater transportation and wastewater treatment. Along<br />
these processes a water balance is made and major flows and stocks <strong>of</strong> chemical<br />
products, nutrients and heavy metals are considered. The direct and indirect<br />
consumptions <strong>of</strong> energy (transportation <strong>of</strong> chemical products and sludge) are also<br />
considered, as well as direct (sewage sludge treatment and disposal) and indirect<br />
atmospheric emissions (derived from energy consumption).<br />
3.2.2 Time horizon<br />
An assessment <strong>of</strong> sustainability should ideally extend over a time horizon <strong>of</strong> several<br />
decades (Lundin and Morrison, 2002). However due to time and data constraints, the<br />
time period considered here is six years, which considers major investments on<br />
improving the technical performance <strong>of</strong> the water system.<br />
3.2.3 Data collection<br />
Data collection for this M Sc research lasted from November the 8 th up to December the<br />
29 th . As starting point staff from the Local Agenda 21 Office provided some reports<br />
concerning water management in <strong>Zaragoza</strong> as well as specific features <strong>of</strong> the <strong>Urban</strong><br />
<strong>Water</strong> System and its evolution during the last decade.<br />
Most time was devoted to carefully review those reports in order to fully understand the<br />
sustainability issues that have been already identified by the municipality as well as<br />
other issues, probably neglected so far and which might be interesting for the <strong>SWITCH</strong><br />
project.<br />
Recent data necessary to perform mass and energy balances are partially available in<br />
different electronic formats such as notepad, pdf, word, excel, etc. Historical data are<br />
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