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 />
• From 2002 when water infrastructure started being upgraded, unaccounted<br />
water has been decreasing in 7% every year. Funds to continue upgrading<br />
are available. In addition to this, demand management is going to be<br />
implemented as demonstration activity for <strong>Zaragoza</strong> within the <strong>SWITCH</strong><br />
project. Therefore unaccounted water is expected to continue reducing. If<br />
current reduction rate is sustained, then unaccounted water will be around<br />
10% <strong>of</strong> total withdrawal by 2020.<br />
• Since most components <strong>of</strong> water infrastructure either are being upgraded or<br />
have been recently upgraded, there is no possibility that existing DWT and<br />
WWT technology in <strong>Zaragoza</strong> will change before 2020.<br />
• Consumption and production patterns in Spanish society are assumed to stay<br />
the same, or will even increase by 2020. Therefore pollution loads to the<br />
sewage system will increase at the same rate as population is increasing.<br />
4.4.3.3 Suggested strategy: Industrial water recycling<br />
4.4.3.3.1 Effect <strong>of</strong> water recycling on water withdrawal<br />
Under Sc3 scenario <strong>Zaragoza</strong> population is expected to be 14% larger than now by<br />
2020. As shown in figure 21, water withdrawal is expected to reduce from 64 million<br />
m 3 in 2006 to 56 million m 3 in 2020 just as a consequence <strong>of</strong> infrastructure<br />
upgrading, meaning 14% reduction <strong>of</strong> current water withdrawal. If the city aims to<br />
reduce water withdrawal below 56 million m 3 by 2020, then also domestic and<br />
industrial water consumption must be reduced. Current strategies going on in<br />
<strong>Zaragoza</strong> also aim to optimize water use for landscaping, however this use only<br />
represents 5% <strong>of</strong> total water requirements (including groundwater). Therefore such<br />
strategy is not going to have a significant effect.<br />
Presently domestic consumption in <strong>Zaragoza</strong> is already 110 l person -1 day -1 , which is<br />
already a low consumption, to reduce it below this level is not very likely. On the<br />
other hand, current industrial water needs in <strong>Zaragoza</strong> are approximately 40% <strong>of</strong><br />
total water requirements (including groundwater). A suitable alternative for continuing<br />
reducing water requirements <strong>of</strong> <strong>Zaragoza</strong> city would be recycling industrial water. For<br />
this scenario analysis two strategies consisting on 10% and 30% recycling are<br />
considered. This will represent additional 2% and 7% less water withdrawal<br />
respectively (see figure 21). This strategy considers both tap and groundwater.<br />
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