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Malaysian Water tariff influences water-saving habits – Interview with CC
Heng of Taliworks (Malaysia) about water supply in Langkawi.
Article · January 2011
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With . . .
GOVINDARAJAN VENKATESH AND
CHAN CHIANG HENG
Malaysian Water Tariff
Influences Water-saving Habits
Venkatesh
Heng
32
The Langkawi Archipelago, in the Andaman Sea of the Indian Ocean, comprises a cluster of 99
islands just off the shores of the Northern Kedah State in Peninsular Malaysia. During low tide,
the number of islands expands to 104. Many of these islands are rocky outcrops separated by narrow canals through which only sampans—little boats—can travel. Langkawi Island (approximately 185 square miles) is the largest of the islands. It is not much smaller than Singapore, but
has a population of only 100,000 people, compared with Singapore’s 5 million. The water
demand has been growing in concert with a rise in population and an increase in per-capita water
consumption. G. Venkatesh talks with Chan Chiang Heng, advisor to the Engineering and Water
Supply Division of the Taliworks Corporation of LGB Group in Malaysia.
Langkawi has an economy that has always
been dependent on water, with fishing and
rice paddy cultivation being the prime drivers.
Now tourism has taken over as a revenue
earner for the archipelago. Has this reduced
the stress on water resources in any way?
economic development and sustainability
of Langkawi. Such shortfalls are partially
addressed by supplies from Malut Dam,
which are released directly to Padang Saga
2 and 3 and the Bukit Kemboja water
treatment plants (Table 1).
Before 1987, Langkawi’s economy mainly
depended on fishing and paddy cultivation,
supporting a rural population of about
35,000 people. In 1987, Langkawi was
declared a duty-free zone to accelerate the
development of the tourism industry. A
National Water Resources Study conducted
at that time showed that the island had adequate water resources, thanks to the rainfall
it received during the year. Now, however,
the population has swelled to 100,000, and
there is an influx of tourists. As a result,
Langkawi now experiences water shortages.
Another factor influencing raw water
scarcity is the establishment of fish and
prawn farms, which are vital for the socio-
Could you comment on the water sources
that the Langkawi water supply system relies
on? Is there one or are there multiple sources
catering to the needs of different segments of
the population?
J ULY 2 0 1 1 | J OURN A L AW WA
Langkawi had traditionally relied on rainfall for its water resources. Groundwater
sources are scarce. To meet the rise in drinking water demand, a water treatment plant
with a maximum capacity of 54.55 million
L/d (Table 1) was constructed in Perlis (on
the Malaysian mainland) in 1997. Treated
water is pumped to Langkawi through a
38-kilometre-long, 754-mm-diameter steel
underwater pipeline.
2011 © American Water Works Association
How is water treatment accomplished?
The source of surface water to the Pulau Tuba (an
island 3.8 kilometres to the southeast of Langkawi)
water treatment plant dries up at times; therefore,
treated water is piped there from Langkawi through a
300-mm underwater pipeline. The treated water is then
pumped from the treatment plant into the main reservoirs and from there to service reservoirs for transmission by gravity into the distribution system.
What is the major pollutant/contaminant in Langkawi’s raw water, and what measures are undertaken to
remove it? What is the composition/characterization of
the water supply in Langkawi with regard to turbidity,
hardness, and bacterial content?
In Langkawi, the main contaminant in surface raw
water sources is ammonia from the paddy
plantations; at the Sungai Baru Treatment plant in
Perlis, the main contaminants are iron and
manganese from the irrigation canal. The
concentrations are low; ammonia can be removed by
chlorine, and iron and manganese can be separated
by using potassium permanganate. The Ministry of
Health has prescribed the Drinking Water Quality
Standard, and as far as the three parameters of
turbidity, hardness, and bacteria are concerned, the
maximum acceptable values are 5 ntu for turbidity,
500 mg/L (expressed as calcium carbonate) for
hardness, and absence of coliform bacteria.
Is the water supply metered, and are charges levied per
consumption or is there a flat-rate system?
Water supply to all categories of consumers is
metered, and charges are levied according to what is
consumed. Consumers are classified into six categories,
and a different tariff is levied on each, depending on the
consumption quantities. Household consumption and
consumption in government buildings, for instance,
have the lowest tariff rate.
Has there been an increase in the per-capita consumption of water among the population over the years, or
are water-saving habits entrenched into the community?
There has been a steady rise in the per-capita water
consumption in Langkawi—this applies to the whole of
Malaysia. Although water-saving habits are encouraged, the effects have not been significant enough.
The likely reason is that water comes cheap!
Can you comment on leakage and other nonrevenue
water in the distribution network? Are any efforts being made to reduce these?
The treated water pumping station at Bukit Kemboja water
treatment plant, which is located in the center of Langkawi.
Leakages in the water distribution system are high
because to the preponderance of old pipes in the network—asbestos–cement pipes being the main culprits.
To reduce leakage, a nonrevenue water survey is carried out periodically. The distribution system is
divided into 21 district meter zones. Pressure-reducing
valves are used to bring down the supply pressure in
the distribution system; this helps reduce leakage
to some extent.
What is the electricity mix used during treatment and
supply? Does the utility monitor energy consumption
in per-unit water-treated terms? Are efforts being directed to improve efficiency? What is the annual expenditure on energy for treatment and pumping through
the distribution network?
In Langkawi, the energy consumption for water treatment and water pumping to consumers is lumped
together to estimate specific costs (per cubic metre of
water produced). Efforts such as monitoring the efficiency of the pumps and refurbishing the casings and
impellers are carried out regularly as part of scheduled
maintenance activities. The annual expenditure on electricity consumption is about 7.5 million Malaysian
ringgit ($2.48 million).
Are the chemicals used during the treatment process
indigenously sourced, or is there an import component?
What are the annual costs for chemicals used for
treatment?
Aluminum sulfate is used for coagulation in liquid or
granular form, hydrated lime is used as a powder for pH
conditioning, sodium silicofluoride is used for fluoridation, chlorine gas for disinfection, and potassium per-
2011 © American Water Works Association
JO U RN A L AW WA | JU LY 2011
33
The sedimentation tank at Padang Saga 2 water treatment plant has
The intake area of the Sungai Baru water treatment plant is located
a capacity of 5.4 million litres per day.
on the mainland in Perlis.
manganate as is required for oxidation. Potassium permanganate and sodium silicofluoride are imported; the
others are locally sourced. The total annual expenditure
on chemicals for water treatment is around 1 million
Malaysian ringgit (approximately $33,000).
If you would have to rank the two leading sustainability challenges as far as water supply in Langkawi is
concerned, what would they be?
Is there a reuse component, or will there be one in the
future in which wastewater can be treated and cascaded
for reuse? Or will that be necessary at all, considering
that water scarcity is never a concern in Langkawi and
Malaysia in general?
No wastewater reuse is practiced at this time. To
conserve raw water in Langkawi, tapping of available
raw water from any natural source—for example,
from the Telaga Tujuh (Seven Wells) for about seven
months of the year—is a common practice. However,
there is a plan to consider the reuse of wash water
from the treatment plant.
TABLE 1
34
Water treatment plants in the Langkawi
Archipelago
Name of Plant
Design
Capacity
million
L/d
Location
Padang Saga 2
5.4
Langkawi
Padang Saga 3
18.2
Langkawi
Bukit Kemboja
8.6
Langkawi
Pulau Tuba
0.45
Pulau Tuba
Supplies Pulau
Tuba only
Sungai Baru
54.55
Perlis
(mainland)
Supplies Langkawi
and Pulau Tuba
(island)
J ULY 2 0 1 1 | J OURN A L AW WA
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Comments
Supplies Langkawi
only
I would pinpoint an increase in treated water demand
and land clearing for infrastructure development.
What is the employment—direct and indirect—provided
by the water treatment and supply sector in Langkawi?
As the concessionaire responsible for the operation,
management, and maintenance of the treatment plants
and distribution of water, all personnel are directly
employed by Taliworks Corporation. Informal labor is
often resorted to for emergency work.
Could you give a split among the shares of the different consuming sectors: households, agriculture, and
industry and commerce?
Water for agriculture—which is purely raw water—is
supplied by another water authority. As far as the consumption of treated water is concerned, there is an
almost equal split between households on the one hand
and industry and commerce on the other.
—G. Venkatesh is a post-doctoral researcher at the
Department of Hydraulic and Environmental
Engineering in the Norwegian University of Science
and Technology in Trondheim, Norway. He may be
contacted at vekatesh.govindarajan@ntnu.no. Chan
Chiang Heng works at Taliworks Corporation of
LGB Group in Malaysia, which supplies potable
water partially to the State of Selangor and
Wilayah and wholly to the District of Langkawi
in the northwestern part of Malaysia.
2011 © American Water Works Association