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

Matrix for Determining the Type of Distribution Systems
Chapter 3 · Decision Support Model (IUWS-DSM) 59
For easier manipulating the rules, one matrix is built up in Figure 29. In the matrix,
horizontal axe represents the water quantity, where three types of water quality are situated
in vertical direction. The up or/and down arrows in the matrix indicate that its water amount
can be merged with the other portion (following the arrow direction). The horizontal double
arrows indicate that it is possible to be handled in the same methods as both sides.
Meanwhile, the percentages as critical conditions set up in the matrix are 20%, 30%, 50%
and 60%. Such numbers can be either directly adopted or varied according to the local
conditions. Based on the matrix, the rules are established and listed in Table 20.
Quality
Quantity
(%)
Suggested
networks
Quantity
(%)
Suggested
networks
Quantity
(%)
Suggested
networks
Quantity
(%)
A 0 ————— 30 ————— 60 ————— 100
dual
↔
both possible
single
B 0 ————— 20 ————— 50 ————— 100
↑
merged with
A
↕
merged with
A or C
↓
dual
(with C)
C 0 ————— 20 ————— 50 ————— 100
↑
merged with B
↔
both possible
dual
Figure 29: Matrix for determining the type of distribution systems
Table 20: Rules for determining the type of distribution systems
No. IF (quantity of Quality X) THEN explanation and consideration
1 A < 30% Dual drinking water pipes have small sizes; dual system
can be compensated by reduced treatment cost
2 A + B < 30% Dual the same as the above case
3 A > 70% Single due to the economies of scale, the parts of
Quality B and C should supplied together with A
4 A > 30% and
A + B > 70%
Single as reduced treatment cost probably cannot cover
the second pipe system
5 direct non-potable reuse Dual it is forbidden to cross connect potable water and
reclaimed water, so dual system is prerequisite
6 rest situations both
possible
except above situations, the types of distribution
system have to be figured out case-to-case