design parameters & criteriaa
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Appendix C
DESIGN PARAMETERS AND CRITERIA
In general, the JKR Design Criteria and Standards for water Supply (1989) as adopted by the MWA Design Guidelines for Water Supply System (1994) form the basis for the design of the treatment work.
Treatment Plant
Process Unit Design Parameters/Criteria
1.1 Aerator
i) Type
ii) Total Overfall
iii) Surface Loading
iv) Diameter
1.2 Mixing Chamber
i) Type
ii) Retention Time
iii) Size
1.3 Flocculation Tank
i) Type
ii) No. of Units
iii) Retention Time
iv) Size
Multi tray
2m
40 m³/( m²/hr)
4.0m
Mixing of mechanical flush mixer
1 min
2.0m x 2.0m x 2.5m SWD
Mechanical Flocculator
3
25 min (all tanks working)
9.5m x 4.2m x 2.0m SWD
Appendix C
Treatment Plant
Process Unit Design Parameters/Criteria
1.4 Sedimentation
i) Type
ii) No. of Units
iii) Detention time
iv) Desludging
v) Size
1.5 Filtration
i) Type
ii) No. of Units
iii) Flow Control
iv) Max Filtration rate(two tanks out of service)
v) Tank Depth
vi) Backwashing
vii) Air source rate
Clarifier tank with tube settlers
3
1 Hour
Daily by timer – controlled electrically operated butterfly valves
10.1m x 4.2m x 4.5m SWD
Rapid gravity sand filter
3 (single bed)
Constant rate filter
7.5m/hr
4.5 m
Combined air water wash
6 cum/hr at 0.35 bar per sq.m for 6 minutes
Appendix C
Treatment Plant
Process Unit Design Parameters/Criteria
1.5 Filtration (continued)
viii) Combined wash water rate
ix) Rinsing wash water rate
x) Size
1.6 Backwash tank
i) No. of units
ii) Capacity
1.7 Chlorine Contact Tank/ Clear Water Tank
i) No. of tank
ii) Capacity
iii) Detention
ix) Size
8 cum/hr per sq.m for 6 minutes
20 cum/hr per sq.m for 9 minutes
9.0m x 6.0m
1 unit
270m³(sufficient for two filter bed washes and plant usage)
2
650m³
2 Hours
12.6m x 11.5m x 4.5m SWD
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