Transcript Slide 1

Water Services National Training Group
and
National Federation of Group Water Schemes
7th Annual Rural Water Services
Conference
18th September 2008
Treated Water
Demand Management,
Leakage Control & Conservation
Joe Gallagher
N.F.G.W.S
Introduction
• The Need for Water Demand Management?
• Implications of high Unaccounted for Water (UFW)
• Reducing UFW on Group Water Schemes
• New Training Course
Reducing daily water demand on
Group Water Schemes
Why is there a need for Leakage Control on
Group Water Schemes?
Example of DBO Schemes in Year 2 of O&M Contract
Design
Demand
m3/day
Actual
Usage
m3/day
% of
Design
Demand
A
246
391
158%
GWS in middle of upgrade – installing meters
B
68
102
150%
Planning a full network upgrade & metering
C
182
243
133%
Meters not yet installed
D
112
141
125%
Only meters on farm connections
E
560
613
109%
Not charging on the meters
F
362
370
102%
Not charging on the meters
G
366
244
94%
Upgrading works ongoing
H
67
50
75%
GWS charging on meters
I
210
117
55%
GWS charging on meters
GWS
Comments
Reasons Schemes exceed design demand
• Deficient distribution networks
– Major leaks
– Lack of PRVs
• Lack of Metering
– Bulk Meters
– Universal Meters
• Charging policies
– Over reliance on flat rate charging
– Resistance to realistic usage charge
• Unknown Sources of Demand
Leakage in Distribution Mains Vs Consumer Side
• Leakage across 6 GWS in Co. Mayo
GWS
Distribution System Consumer Side
1
13%
87%
2
15%
85%
3
26%
74%
4
30%
70%
5
34%
66%
6
45%
55%
Slide Sourced from Ryan Hanley Consulting Engineers
What are the Implications of UFW?
• Cost
• Capacity of treatment plant
• Sustainability of source
• Quality
• Supply & pressure
Galway GWS (90 Houses)
Daily demand
UFW % (m3/day)
Cost of UFW
(Savings)
Distribution System
Consumer Side
May 2006
Target
142 m3/day
71 m3/day
60% (85)
20% (14)
€10,835.40/year
€1,761.91/year
(€9,073.49)
35% UFW
65% UFW
10 connections accounted for 45% of
daily demand.
Burst in Distribution Pipe Network
•
At a pressure of 30m (3 bar) the following losses
will occur:
Size of hole
m3/day
€ Cost /day (@ 80 Cent per
m3)
1mm
1
€0.80
3mm
9
€7.20
5mm
25
€20.00
7mm
44
€35.20
Av. Mains
Leak
74
€59.20
Slide Sourced from WSNTG Leakage Control in Rural Supply Networks
Extent of Water Loss From Leaks/Bursts
•
At a pressure of 30m (3 bar) the following losses
will occur:
Size of hole
m3/day
Cost/day
Cost/yr
(@ 80
Cent/m3)
(@80 Cent/m3)
1mm
1
€0.80
€292.00
3mm
9
€7.20
€2,628.00
5mm
25
€20.00
€7,300.00
7mm
44
€35.20
€12,848.00
Av. Mains
Leak
74
€59.20
€21,608.00
Slide Sourced from WSNTG Leakage Control in Rural Supply Networks
The Cost of Water
Typical Litre
of bottled
water €1.20
What is this load worth?
A 450m3 reservoir @
€1.20/l would store water
worth €540,000
Cost Implication for Scheme Members
Figures from a GWS:
No.
2005
(m3)
2006
(m3)
Leakage
m3
Cost
1
2
3
114
9,577
173
7,609
15,300
4,805
7,495
5,723
4,632
€5,996.00
€4,578.40
€3,705.60
4
5
6
7
5,777
709
4,495
363
8,681
2,186
5,686
755
2,904
1,477
1,191
392
€2,323.20
€1,181.60
€952.80
€313.60
• GWS charge is 80 cent/m3
(€3.60 per 1,000 gallons)
Capacity of Treatment Plant
• Ability of Treatment Facility to cope
– Design Demand
– GWS with high UFW reach their Design Demand
much more quickly
– Plant failure, water outages and/or failures in
water quality
Sustaining the Source
• Excessive abstraction
– This will impact on surface and groundwater supplies and
may result in:
• Slower recharge of the source
• Poor quality raw water being drawn into the treatment
plant
• Increased costs for monitoring and treatment
Supply & pressure
• Potential difficulty in admitting new members
– A scheme with 50% UFW has the capacity to increase its
domestic membership by a third when UFW is reduced to
25%!
• Members situated on the network beyond a leak in
the system may be affected by poor pressure and
breaks in supply
Calculating Legitimate Demand
• Average daily usage figures from the National Water
Study:
Demands
People
Cows
Dry Stock
Others
Litres/hd/d
136
90
45
5
• Schemes need to estimate the numbers served on the
scheme in relation to:
– Human population
– Dairy Cows
– Drystock
– Others (e.g. Sheep/Calves/Poultry/Mushroom)
Setting Targets
• 25% UFW is considered acceptable, but is it enough?
• Kilmaley Inagh GWS – 1900 Houses with < 10% UFW:
– Installing /Monitoring district & consumer meters
– Isolating the network into District Metering Areas (DMAs)
– Repairing leaks and replacing critical mains
– Monitoring the distribution network on a consistent basis
– Implementing realistic pricing policies, based on usage
Setting Targets
Erne Valley GWS - > 1,100 Houses (2007 Figures)
• Original Usage
5,700 m3/day
• Target
3,000 m3/day
• 2007 usage
3,300 m3/day
• 2008 usage
2,900 m3/day
• UFW (REDUCTION)
2,800 m3/day
• 49% Reduction
• Saving to Scheme > €250,000 aprox. p.a.
Reducing UFW in Distribution Network
• Reduce Distribution
Network to < 25% UFW
4” Pipe
3” Pipe
2” Pipe
District Meter
Service Pipe
M
Consumer Meter Box
Reducing UFW in Distribution Network
• Reduce Distribution
Network to < 25% UFW
• Typical District Metered Area
4” Pipe
3” Pipe
2” Pipe
District Meter
Service Pipe
SV
M
SV
Consumer Meter Box
Reducing UFW in Distribution Network
• Reduce Distribution
Network to < 25% UFW
• Typical District Metered Area
• Possible solutions identified
• Consult with GWS Engineer
Leaks
Critical Mains Rehab
District Meter
SV
PRV
M
SV
Pressure Reduction Valve
Reducing Pressure from 70m to 40m should
reduce leakage by 55%
Consumer Meter Box
GWS with 90 Houses
• What Caused this Fluctuation in Measured Daily Usage on this GWS?
GWS with 90 Houses
Meters Installed
GWS with 90 Houses
Meters Installed
Bills Issued
Mayo GWS (150 Houses)
• This Part - Private Mayo GWS
successfully reduced its UFW through:
– Active Leakage Control
– Critical Mains Replacement
– Pressure Reduction
– Demand Management
Mayo GWS (150 Houses)
• The results can be seen in the table below:
Mayo GWS
Operating System
No. of Domestic
Connections
Demand into
Supply
UFW
Cost of UFW/year
@ 80cent/m3
Before
After
1 booster zone
2 zones – gravity +
booster
150
150
479m3/day
185m3/day
334m3/day (70%)
20m3/day (11%)
€70,373
€5,840
Reducing daily water demand on
Group Water Schemes
• Requirement for training in Water Demand
Management
• Developed by the NFGWS as an introductory
course to be delivered to the GWS sector in
advance of the more detailed WSNTG course:
“Leakage Control in Rural Supply Networks”
Course objective
• To provide a practical framework for
schemes dealing with high levels of water
wastage, in particular unaccounted for
water (UFW)
and
• To assist those schemes wishing to maintain
and improve their current low levels of
water wastage and UFW.
Course Format
• Four Modules
–
–
–
–
Module 1:
Module 2:
Module 3:
Module 4:
What is UFW?
What are the implications of UFW?
How can UFW be quantified?
How can UFW be reduced?
Conclusion
• High UFW will have cost, capacity and supply implications for
GWS and the individual member
• High UFW may affect the sustainability of the source and also
the quality of water supplied
• UFW must be reduced
• This Course is design to do exactly that
– Delivered in your locality
– < 3 Hours to complete
– At €75 per head it’s a steal!!
Contact Details
Joe Gallagher & Barry Deane
Training Co-ordinators
N.F.G.W.S.
12 Henry Street
Tullamore
Co. Offaly
Tel / Fax: 057 9328068
Water Services National Training Group
and
National Federation of Group Water Schemes
7th Annual Rural Water Services
Conference
18th September 2008