Case Study SA-EMF
LEAKAGE REDUCTION AND WATER CONSERVATON
All aspects of the water cycle draws benefit from water conservation and demand management. Two
principles apply: i) any form or magnitude of leakage reduction will have a proportional energy demand; and
ii) leakage is driven by pressure. This case study considers pressure management as 1st order intervention to
reduce leakage and increase energy efficiency.
Pressure Management as Water Demand Management Intervention
Description of Process:
Water leakage accounts for a significant portion of energy along the value chain of the water cycle.
Infrastructure which has neglected through inadequate maintenance and replacement resources are
particularly inefficient and gives cause for even high efficiencies downstream of the water cycle. Leakage
is driven by water pressure. Hence, any reduction in pressure will result in lower leakage and reduced
damage to pipes and pumps. The efficiency benefits are almost outweighed by the monitory benefits,
especially in municipalities with a poor pollution and tax base. Pressure Management is therefore one of
many possible WDM interventions that has successfully been applied in South Africa.
The project involved the design, installation and
commissioning of a pressure reduction chamber with
appropriate sizing, fitting and operation of the valves,
pipes, meters, strainers and monitoring equipment. The
project involved cutting into existing water mains and
replacing section with smaller diameter pipes and
equipment. The chamber was operated to reduce
pressure during off peak periods and restore to higher
pressure during high demand period.
Potential Interventions

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Pressure reduction is a 1st order intervention to be followed in series or parallel with
complimentary actions within a holistic Leakage Management strategy
Proactive reduction of water losses to a target value, reducing pressures to minimum targets in
identified areas, pursuing asset renewal projects, metering to check and monitor supply zones for
losses, and minimise repair times for visible and detected leaks
Reactive pressure control would imply a response is only afforded once the municipality becomes
aware of a supply or pressure problem in an area. be to respond timeously to reported bursts,
consumer complaints, and unexpected changes in flow or pressure.
Performance contracting to water supply is key to low capacity municipal suppliers.
Range of potential savings
Reported leakage for a well managed system is typically below 15% whereas in Sebokeng it was
estimated to be in excess of 70% due to a number of factors including many years of low investment and
poor maintenance. The reported cost saving from this project has been US$ 3.8 million/annum, 14
million kWh/annum and 8 million kiloliter water saved. The annual GHG emissions avoided was 12,000
tonnes. Payback on investment was 3 months.
Case Study SA-EMF
Case Study SA-EMF
Case Study SA-EMF
LEAKAGE REDUCTION AND WATER CONSERVATON
Case Study SA-EMF
Ref
Response information, description and remarks
1
Location:
South Africa, Emfuleni Local Municipality to the south of Johannesburg
in industrial and urban area.
2
Sector:
Clean water
3
Works Owner or Operator:
The supply systems are owned and operated by Metsi-a-Lekoa, an
entity established to manage the supply of potable water to the 1.2 m
residents in the Sebokeng and Evaton area. The set up of the project
was done via investment made by the developer (private sector) in a
PPP arrangement over 5 years.
4
Size:
1.2 million residents are served in the Sebokeng and Evaton area, as
well as >120 industries (ERWAT). Some 70 000 low income households
are connected to the system with individual water supply and
waterborne sewage. The leakage at the start of the project was 2800
m3/hour.
5
Energy Provider:
Power is in form of electricity, provider by the national electricity
agency, ESKOM. Energy cost has increased drastically from 2010
onwards and an average annual increase of 13% per annum is
announced. Retail tariffs is at R 52 c/kWh (2011/12) and 65 c/kWh
(2012/13) whilst municipal tariffs is as high as 22 c/kWh for >600
kWh consumers.
6
Process:
No biological or chemical agents involved in case. Physical in so far as
new / renewed infrastructure involved as under item 9.
7
Component:
Involved the cut-in to a 1.2m diameter and 700mm diameter main and
the construction of a large chamber to house the various valves and
fittings needed to control the water pressure.
8
Motivation for the case study:
All water used in the area has been pumped by approximately 400m
and so any savings in water create direct energy savings through the
reduced pumping.
9
Process/Plant changes:
All plant used for composting with a bulking agent was used in the new
operation. The existing inclined face compost turners were converted
to sludge turners at a third of the cost of new machinery. Only 12 year
old tub grinders were scrapped.
10
Civil/Physical Changes:
Reduced pressure, water quality remains constant, reduced pressure
has positive impact on life expectation of the infrastructure.
11
Operational Changes:
As a result of the reduction in leakage, it was possible to address many
long-term outstanding problems such as pockets of intermittent supply
which have improved the level of service to the 500 000 residents.
12
Risks and Dependencies:
Private sector investment was required to bridge financing constraints.
Active community participation is crucial to ensure acceptability of
initiative and negate vandalism and create awareness. The success of
the project created awareness of the problems in the area which has
acted as a catalyst for further funding support.
13
Implementation:
The project was procured as a Private Public Partnership Project
where the investment was repaid over 5 years from savings from the
project. Design, build and installation was done by the PPP partner –
WRP Consulting, Operation was undertaking by Emfuleni
municipality operations utility Metsi-a-lekoa.
14
Energy Efficiency gains:
An estimated 14 million kWh has been saved annually and gains are
still ongoing and estimated at this rate. The energy savings translate to
65 000 tonnes of CO2 per over the 5 year period.
15
Cost/Benefit analysis:
The project cost is recorded at R 10m (Euro 1 millin) to construct and
operated of a 5 year period. The project achieved audited water
savings of 50 million m3 over this period, which represent >R150
million (US$3.8 million) in reduce water purchases by the local
municipality. A pay-back period of < 3 months was confirmed.
16
Project review:
Longer term investments required, ensure sufficient O&M budgets and
technical and managerial skills in place before PPP closes out.
17
Confidence grade:
High confidence, data focus on financial aspects with supportive data
and information. However, audited results would imply that
engineering and scientific fact is in place and factual. Water savings
were accurately monitored and accounted for. The associated energy
savings are calculated directly from the water savings, based on
conservative calculations.
Emfuleni Local Municipality is
located to the south of
Johannesburg in the industrial
heartland of South Africa. A
separate water utility called
Metsi-a-Lekoa was established to
manage the supply of potable
water to approximately 1.2
million
residents
of
the
Municipality of which 450 000
are located in the Sebokeng and
Evaton areas. Water is in turn
supplied to Metsi-a-Lekoa from
the local bulk water provider,
Rand Water, which is one of the largest providers of potable bulk water in the world.
Leakage measurements indicated figures as high as Minimum Night Flows of 2 800 m3/hr. No storage in the
Sebokeng and Evaton areas, either at bulk reticulation level or domestic property level. The high MNF was
therefore almost completely due to leakage, most of which occurs inside the properties and is therefore not
evident from normal visual inspection. It should also be noted that since most of the leakage occurs inside
the households, the leaking water returns to the sewage treatment plant through the sewer network which
is often overloaded to such an extent that spillages of raw sewage into local river courses are a common
occurrence in the area. Estimates concluded that 80% of the water supplied to the area was lost, which in
turn represented an annual water bill of approximately R120 million per year in 2003 ( ± Euro 15 million).
Figures: i) Minimum Night Flow for Sebokeng/Evaton; ii) MNF where leaks are well managed (Dr R
Mckenzie, 2011)
Description of Process
In 2004, the Municipality appointed WRP Pty Ltd to design and commission an advanced pressure
management installation, as the first phase of a long term strategy to reduce wastage in the area. The
project involved no financial input from the Municipality, as the full investment was made by the Project
Team based on a risk-reward model.
A 10m x 10m x 5m chamber was built containing
the various pipes and valves required to manage
the water pressures into Sebokeng and Evaton.
Since leakage is driven by water pressure, any
reduction in pressure, even if only for a short
period each day, will result in lower leakage as
well as fewer new burst pipes. If water pressures
can be lowered significantly during the off-peak
periods (especially at night) then very significant
savings can often be achieved. The installation
involved cutting into the two existing water mains and replacing a short section with a series of smaller pipes
and associated valves, meters, strainers etc. The water pressures can be reduced during off peak periods
and restored to the original high pressures during periods of high demand. In this manner, the leakage from
the system as well as the incidence of new burst pipes was greatly reduced.
Figure: Schematic representation of the pressure management installation (Watergy, 2007)
Potential Interventions

Pressure reduction is a 1st order intervention to be followed in series or parallel with complimentary
actions within a holistic Leakage Management strategy
Proactive pressure management imply the reduction of water losses to a target value, reducing
pressures to minimum targets in identified areas, pursuing asset renewal projects, metering to check
and monitor supply zones for losses,
and minimise repair times for visible
and detected leaks
Reactive pressure control would
imply a response is only afforded
once the municipality becomes
aware of a supply or pressure
problem in an area. be to respond
timeously to reported bursts,
consumer
complaints,
and
unexpected changes in flow or
pressure.
Conformance to the SA Presidential
targets
which
include
“50%
reduction in water losses by 2014”.
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The project has been recognised both for its initial design as well as for the 5-year PPP model which were
used over the 5 year project period. Sasol has recognised the model and will be applying the same principles
in future project where the industry water footprint can be offset or reduced via similar initiatives.
Benefits derived from case study:
The most significant benefit from the project was the savings in water purchases by the Municipality from
the bulk water provider due to the reduced leakage in the Sebokeng and Evaton areas. The final audited
savings achieved by the project are as shown in the following table:
The key results are summarised as follows:
Comparison of Savings between SASOL and Sebokeng Projects
(A Meyer, 5th WWF & UN CEO Water Mandate Workshop,
Istanbul, March 2009)

Performance contracting applied to
the water supply

Payback period of <3 months

Annual cost savings: US$ 3.8 million

Annual energy savings: 14 million
kWh

Annual water savings: 8 million kl

Annual GHG emissions avoided:
12,000 tonnes

Pressure management technology reduced water losses by > 30%.
Cost Saving
In financial terms, the project has
saved in excess of R30 million per
annum (ZAR) due to the reduced
water purchases by the Municipality
from the bulk water provider. These
figures are based on the average cost
of water of R3/m3 which was
applicable during the 5-year PPP. It
should be noted that the cost of
water is almost R5/m3 (2012) and will
increase substantially in future. The
project cost approximately R10 mil
($1.5 mil) to construct and operate
for the duration of the 5-year PPP
project period.
Acknowledgement:
Watergy - Alliance to Save Energy (Feb 2007); Interview Dr Ronnie McKenzie, (2011).