Chapter 3 Decision Support Model (IUWS-DSM) - Tubdok

32 New Conception and Decision Support Model for IUWS
used as the drinking water source. Since non-potable water use is not senible to the water
sources, B and C are used representing that it can be either the treated raw water or the
reclaimed water.
In such situation, the water can be supplied in either one or multiple types of quality. In
reality, maximal two parallel pipe systems are applied. Hence, maximal two types of water
quality can be supplied. Among Quality A(1), B and C, Quality A(1) is indispensable for IUWS.
Therefore, always only one quality between B and C is supplied by the second pipe system.
The symbol B/C is used in the following context that indicates either one of both is supplied.
The symbols of “raw + B/C” and “raw + A(1)” indicate that double water sources are used,
i.e. “raw” represents the local source, and “B/C” or “A(1)” represents the external source
coming form the superior water entity. The case of “B/C + A(1)” is that the superior water
entity has the dual water supply system, which are possible as double external sources. All
possible combinations of water quality as well as their applicability to different types of water
entities are given in Table 8. The decision making mechanism and rules for determining the
supplied water quality are introduced in § 3.3.2.
Table 8: Possible source water qualities and their applicability
no. water
source
possible
quality
no. possible
supplied
CA UD WUU /
WUC
(i) Local raw 1 raw � � �
2 B/C � � �
(ii) External raw 3 A(1) � � �
B/C 4 raw + B/C � � �
A(1) 5 raw + A(1) � � �
Legend: � – applicable; � – not applicable
2.2.3 Desired water supply
6 B/C + A(1) � � �
One goal has to be fully achieved by the desired water supply system, i.e. supplying
sufficient quantity with satisfying quality to water costumers. It mainly deals with two
objectives: the treatment facilities and the distribution systems.
2.2.3.1 options
Traditionally central waterworks treat the raw water to the drinking water quality and
finished water is supplied to costumers with a single water supply system. Nowadays,
diverse water end uses in cities results in diverse requirements of water qualities unevenly
distributed. The hierarchy of the IUWS offers the chance for water entities to have individual
treatment and distribution systems so that the local water system can completely match the
actual requirements. Thus, besides central waterworks and single water system, package
plants and dual water system are also the alternatives.