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The effects of pollution on freshwater resources
Lim, R. P.
1987
Lim, R. P. (1987). The effects of pollution on freshwater resources. In AMIC‑CDG‑COMCON‑UKM Workshop on Mass Media and the Protection of the Environment : Kuala Lumpur, Sep 28‑Oct 10, 1987. Singapore: Asian Mass Communication Research and Information Centre. https://hdl.handle.net/10356/101055
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The Effects Of Pollution On Freshwater Resources
By
RPLim
Paper No.9 ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library
•i * *o^
THE EFFECTS OF POLLUTION ON FRESHWATER RESOURCES
R.P. Lin
Zoology Department
University of Malaya
59100 Kuala Lumpur
Malaysia ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library
Introduction
Water is the life blood of all living things on this planet.
Civilisations were created in areas where water was plentiful and
many present day settlements can still be found close to water
sources. Although three quarters of the planet is covered with
water, freshwater represents less than 3 percent of its total
volume (Table 1). The distribution of this resource is temporally
and spatially uneven and this makes its exploitation difficult
due to the heterogenous demograhic patterns of the human
population. With the advent of industrialisation and large-scale
agriculture to meet the needs of a burgeoning and materially
sophisticated population the demands on the planet's finite water
resources has increased tremendously. Not only do industrial and
agricultural activities consume water but they also cause the
deterioration of water resources through the input of pollutants
such as organic matter and poisons. The degradation of water
quality reduces the availability of water to sustain increasing
economic and social activities. Such perturbations also cause
changes in the ecosystem to the detriment of its inhabitants and
terrestrial life forms that depend on water for survival.
In order to understand more fully the implications of
pollutants on our water resources an insight of the the
hydrological cycle would be pertinent in understanding the
process by which water is recycled in the biosphere. Further,
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freshwater systems under undisturbed conditions would provide
some perspective of the_ naturnl rnnriifinn of vnrrr rnnnrrn mid
its regulation in supply. Next we can look at the effect
pollutants have on water and its biota. This change in water
quality will affect the utility of water resources. In addition,
activities on land such as logging, mining and urbanisation have
tremendous disruptive impacts on the regulatory capacity of rivers because of the close connectivity between the land and
water phases in a watershed. The Linggi River Basin, as a case
study, will serve to illustrate the impact of pollution on water
resources in a basin.
The hydrological cycle
The finite water resources on this earth can continuously
sustain life activitiesonly because of the hydrological cycle.
This cycle consists of several processes involving the movement
of water from the atmosphere onto the land and oceans where it is
stored for various lengths of time before it is recycled back to
the atmosphere (Fig. 1). During its cycle water goes through
three phases: precipitation, evaporation, and surface and
groundwater runoff. In each phase water is transported,
temporarily stored, and undergoes a change in its state (i.e.
gaseous, liquid and solid states).
Water is evaporated into the atmosphere from land and its
water bodies, and the oceans. Evaporation occurs directly from ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library
precipitation, precipitation intercepted by vegetation, oceans,
lakes and reservoirs, rivers, and plant transpiration. The rate
of evaporation in each site is influenced by a multitude' of
dynamic environmental factors.
Once the water reaches the earth's surface it may be
transpired by plants, may run over the surface of the land into
streams as surface runoff, or may inflitrate into the ground
(Fig. 1). A large proportion of the intercepted water and surface
runoff water is returned to the atmosphere by evaporation. Much
of the inflitrated water may be temporarily stored as soil
moisture and evapotranspired while the remainder will percolate
into the deeper zones and stored as groundwater for longer
periods. Groundwater is continually being renewed through
absorption by roots of plants, outflow as springs, and seepage
into streams. The runoff phase" is also very complex and is
influenced by the vegetation, geology and pedology, and climate.
How clean, clear water is maintained i
Although tropical humid regions of Southeast Asia receive a substantial amount of rainfall every year, much of this
precipitates during the monsoon seasons which may extend over a few months. This often results in higher river discharge during
the wet season and reduced discharge during the dry season even under undisturbed forest conditions". However, the amplitude of discharge over the seasons is relatively small compared with
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denuded land. The smoothening out of variations of flow is
greatly influenced by vegetation. The great moderating ability of
the tropical rain forest comes from the fact that the dense
multistoried canopy intercepts raindrops and reduces the rate at
which it reaches the ground surface through a complex process of
leaf drips and stem flows. This allows sufficient time for the
water to percolate into the soil to recharge the groundwater
reservoir. Surface runoff is also reduced. During the dry period
much of the water that flows in rivers and streams is derived
from the groundwater reservoir.
Clean, clear water in undisturbed rivers is maintained
through the efficient nutrient cycling of the forest which
reabsorbs much of the inorganic ions leached from litterfall. Its
nutrient status would largely depend on the geological makeup of
the watershed. The vegetation" also plays a vital role in
preventing the direct impact of raindrops on the soil surface
causing erosion through the loosening of soil particles. Clear
waters and channel volume is thus maintained.
It is clear that vegetation within a watershed is imperative
to maintaining clean rivers and hence sustainable water
resources.
How we pollute our water resources
Economic and social development not only demands greater
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amounts of water but also causes degradation of water resources.
Rivers are commonly treated as convenient dumps for effluent
produced from domestic, industrial, and agricultural activity.
Effluent produced can range from organic material such as food,
faeces, agricultural wastes, to poisons like heavy metals and
pesticides, to erosional material like sand, mud, and silt.
Fortunately, rivers are capable of processing some of this
material through oxidation-reduction, absorption-adsorption, and
precipitation processes. These involve physical, chemical and
biological activities. However, this capability is limited and
any excessive loading of effluent will result in the breakdown of
the system. Groundwater resources can also be contaminated by
persistent poisons produced in industry as well as those used in
agriculture.
The main types of * pollutants produced in developing
countries are domestic and agriculturally based effluent. This is
due to the inadequacy of sewerage treatment facilities to cope
with rapidly growing populations. Industrialisation and education
has resulted in large rural urban migration to service the
industries. Often this leads to the development squatter areas
with little or no sanitary facilities. The river thus serves as a
convenient sewage facility.
Organic matter places high demands on dissolved oxygen
during oxidative breakdown to inorganic components. Under normal
circumstances, such as undisturbed watershed conditions,
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dissolved oxygen is sufficient for aerobic oxidation with the
release of harmless, odourless carbon dioxide. However, when
excessive organic matter is inputed into rivers, anaerobic
oxidation (putrefaction) occurs with the release of toxic and
odorous gases such as methane or hydrogen sulfide which are
lethal to the aquatic biota. Depletion of dissolved oxygen is
detrimental to the biota as it is required for metabolic
purposes. Organic matter is also rich in nitrogen and phosphorus.
When oxidised these nutrients become available to the algae.
Under natural conditions these nutrients especially phosphorus
are low enough to limit production of algae and thus maintain
clean, clear water. When this nutrient limitation is removed as
in most polluted waters algae grow excessively and form surface
scum which inhibits the production of oxygen throughout the water
column. The resulting anaerobic condition leads to the
degradation of water quality and generally upsets the stability
of the ecosystem. *>
Domestic sewage also contains pathogenic viruses and
bacteria which can be hazardous to water users. Apart from
domestic sewage, pesticides can at very low concentrations in the
water be lethal ly or sub-lethally toxic to aquatic animals. Their
long term effects on man are unknown but it is speculated that
they may be carcinogenic. Heavy metals at high concentrations can
likewise have an insidious effect on living organisms including
man. At low concentrations they act through the food chain.
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The Linggi River Basin — a case study
To illustrate the effects of anthropogenic activities on
water resources the Linggi River Basin is taken as example. This
basin is located in Peninsular Malaysia and forms part of the
state of Negri Sembilan. It is a rather small basin with a
drainage area of approximately 1,399 sq. km. The river comprises
two main branches, the Rembau River and the Linggi River (sensu
stricto) with a network of tributaries flowing from their
headwaters in the Main Range (Fig. 2). The water flows eventually
into the Straits of Malacca. The Linggi River is a relatively
fast flowing and shallow river with a mean water depth of less
than one metre in the upper and middle reaches. Marine intrusion
occurs up to 28 km. inland. In terms of landuse the basin is
dominated by agriculture especially rubber and oil palm (Fig. 3).
The basin can essentially be divided into two regions based on
economic activity. The Linggi River sub-basin is highly developed
with intense urbanisation and industrialisation. Seremban town,
the state capital, and Senawang Industrial Estate, the major
industrial centre is situated in the middle reaches of this
river. The Rerabau-Siput River sub-basin is essentially, rural with
rice farming and rubber small holdings as the main economic
activities. Deraographically, the Linggi River sub-basin is
experiencing a JLarge influx of migrants while the Rembau River
sub-basin suffers from out-migration.
The Linggi River is very important to the basin as it
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provides a major portion of its domestic, industrial and
agricultural water supply. It is also used for subsistence
fisheries, navigation and aquaculture. However, the basin is
unique in that the Linggi River is one of the most polluted in
Peninsular Malaysia, and its drinking water is drawn from the
most polluted reach, just downstream of Seremban town. Its water
resource is limited by the size of the river. In addition, it is
an economically active basin due to its proximity to the Kelang
Valley, the main centre of industrial activity in the country.
Sources of pollution
Two types of sources of pollution occur: point source
pollution, and non-point source pollution. Point sources of
pollution come from domestic activity in towns, agro-industrial
wastes especially from oil palm and rubber processing, industrial
effluent, waste from livestock production, and sediment due to
land clearing activities like housing development projects and
road construction. Major point sources of pollution are located
on the Linggi River (s.s.) (Fig. 4). Non-point sources of
pollution consist mainly of nutrient and pesticide runoff from
agricultural land. Typical sources and types of pollution are
given in Table 2.
The total estimated volume of daily effluent input to the A river system is 66,364 cu. metres, or an equivalent Biological fv*
Oxygen Demand (BOD) of 16,628 kg (Table 3). The main contributor
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is domestic sewage at 10,550 kg/day of BOD. This comes mainly
from the Seremban Municipality which contains 45% of the basin's
population. The dominance of domestic sewage is due to inadequate
sanitary and treatment facilities especially in squatter areas.
Water quality
The water quality at various reaches of the Linggi River is
dependent on the type of landuse, effluent inputs, and recovery
at particular reaches. At the headwaters where the area is
forested, the water is. clear and clean with very low nutrient
status, low'BOD, and high dissolved oxygen (Table 4, Figs. 5 &
6). As the water flows towards the sea its quality deteriorates
with increased nutrient status and BOD, and decreased dissolved
oxygen. The deterioration of water quality is greatest just
downstream of Seremban town. Its quality recovers somewhat
further downstream before flowing into the sea. In the more rural
Rerabau area where rubber and rice growing are the main activities
water quality does not deteriorate much with fairly low BOD and
high dissolved oxygen.
Water use
Water for domestic purposes is tapped and processed at four
facilities (Table 5). The main facility is the Linggi Water
Treatment Works at Kuala Sawah located about 8 km downstream of
Seremban town supplies about 80,000 cumecs/day to the Seremban
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and Port Dickson areas. However, the deteriorated condition of
the water poses several problems. Firstly the cost of production
will increase with the elaborate treatment method needed to make
the water portable (Table 6). Secondly the wastage of water
during processing increases with the degree of deterioration in
water quality (Fig. 7). For example the percent wastage increased
from 10% of raw water abstracted in 1966 to 25% in 1983. Thirdly,
the probability of enteric diseases is greater due to the fact
that a substantial amount of untreated or poorly treated domestic
sewage is dumped into the river. Mean coliform levels are 40
times greater than that stipulated by the WHO. In contrast the
Pantai Water Works which draws clean water in the upper reaches
requires little treatment (Table 6).
Development and conservation - maintaining a balance
It is without doubt that development must continue in any
country, but prudent development is the key to optimising the
conservation of one's resources. In the case of the Linggi River
Basin development has proceeded headlong without much concern of
its impact on water resources. In the 50s and 60s.the Linggi
River adequately served the needs of the basin; its water was
then clean as industries were not developed. In the late 70s and
early 80s development proceeded at an unprecedented rate.
Concoramitent with this, populations increased mainly through
immigration. To cope with this, urbanisation- grew with the
establishment of housing estates and squatter areas. Two things
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have resulted from this economic and social change: increased
water demand and increased pollution to their very source of
water supply.
How can one strike a balance between development and
conservation? Resolving this is very complicated as it impinges
upon political, economic, social, and technical issues. In the
first instance a comprehensive management strategy for the basin
must be drawn up. This strategy should include policy essentials
such as a. having a long time frame b. being capable of dealing
with contingencies, c. being capable of accomodating the
excerising of political judgement, d. allowing for refinement
with time, e. considering changing patterns of behavior, f.
having good implementation plans consisting of a decision making
structure, national priorities, administrative structure, and
rational legislation (Nakamura 1986). The challenge will be to
resolve issues pertaining to the supply of adequate clean water
for continued economic growth of the basin with minimal
degradation to the environment particularly its water resources.
Thus any development activity must be evaluated in relation to
its overall impact on the water resources in the basin. This
evaluation can be based on the Environraental__Jjnp^r±_Assessraent.
An overall water resource policy should be formulated so
that management of water resources may be optimised. Presently
there is the uncoordinated exploitation of water resources by
government departments and the private sector resulting in
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conflicts between users. Water related departments, in addition
have little jurisdiction over land development matters which
often impinge on water resources. This policy may be implemented
by an authority which has jurisdiction on land development
matters that affect the water resources of the basin. Furthermore
this policy will enhance the enforcement of pollution related
laws.
The implementation and enforcement of pollution laws can
greatly enhance management strategies. Malaysia has several water
related and pollution laws, but these are not fully enforced due
to economic, political and bureaucratic constraints. Close
monitoring of pollutant inputs and prosecuting offenders will
alleviate the further degradation of water resources. Water
quality standards in rivers should also be set. Presently only
effluent standards have.been se-t, but this does not solve the
combined inputs of increasing numbers of industries which may be
discharging effluent within the standards set. The implementation
and enforcement of land building codes will also greatly reduce
erosional load in the river.
Improvement of sanitary and sewerage facilities especially
in urban centres like Seremban will greatly reduce pollution of
the river. In addition, cottage industries and small scale animal
husbandry activities that pollute should be relocated to areas
with proper treatment facilities and preferably away from rivers.
This however, can be an expensive exercise, and is disruptive to
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the social structure. It also requires great determination on the
part of the decision makers and impleraentors. Such an exercise is
possible as is exemplified in Singapore where the once polluted
Kallang River Basin was cleaned up over a 10 year period. Today
fish inhabit the waters and the waters are clean enough for water
related recreation. The driving force behind the project was the
prime minister, Mr. Lee Kuan Yew.
Locating new industries in industrial estates with proper
treatment facilities will also greatly reduce pollutants into
rivers. Also attracting less polluting and water demanding
industries will further alleviate pollution of water resources.
Concluding comments
It has long been acknowledged that environmental problems in
developing countries are more diverse and diffused compared with
developed countries (Nakamura 1986). These problems include
excessive deforestation leading to soil degradation,
environmental pollution caused by poorly regulated
industrialisation and urbanisation, and large r.ural-urban
migration. Resource planners and decision makers have thus the
unenviable task of developing a comprehensive strategy. Due to
the complexity of issues involved, the formulation of a
management strategy would require inputs from a diverse spectrum
of expertise. This requires the development of appropriate human
resources who must be familiar with the local socio-political
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situation and the aspirations of the state and nation. Good
management strategies must include their practicality in
implementation based on economic and political considerations.
The full realisation of management strategies is dependent
on a number of factors. Among these are firstly, an understanding
of the long term impacts of unmitigated pollution on water
resources, and the consequences of this to the future development
of a particular basin by decision makers. Secondly there must be
the political will among decision makers to be fully committed to
the management of the basin over a long time frame. However, the
implementation and enforcement of management strategies can only
be accomplished only if there is the development of
administratively and technically trained human resources. The
role of the public is also crucial to the success of any
management strategy. Quality of life should not be perceived only
as monetary gains at the expense of the environment. Institutes
of education, environmental groups, and the mass media can play
an important role in educating the public on the importance of
conserving our environment and resources not only for ourselves
but more importantly for future generations.
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Reference Cited
Nakamura, M. (1986) : Policy analysis perspectives in environmental planning and management. Expert Group Workshop on Environmental Planning and Management for Local and Regional Development, Japan. November, 1986.
*
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Table 1 : Relative volume and Renewal periods of water on the earth.
Percent of Total Renewal time
Ocean 97.61 37000 years
Polar ice, glaciers 2.08 16000 years
Groundwater 0.29 300 years
Freshwater lakes 0.009 - 1-1000 years
Saline lakes 0.008 10-1000 years
Soil and subsoil moisture ( 0.005 280 days
Rivers 0.00009 12- 20 days
Atmospheric water vapour 0.0009 9 days
Extracted from Wetzel RG 1975 Limnology
ft Table 2 : Sum-nary of the activities of industries, effluent generated and their disposal in the Linggi River Basin.
Factory/loccStion Major raw Material Water Effluent Disposal Receiving
material input output source type method stream A T T Textile/Textile Products E N T I Chempaka Textile, viscose, cotton, O yarn, spinning dye water chemically Simin River N :
Senawang polyster, dyes
with other treated T
chemicals h e
S i Kim Fashion, acrylic, cotton, socks, caps, dye water chemically Simin River n g
Senawang wool, oxford, pullovers, hand- treated a p
nylon, dyes gloves, yarn o r e
C
Chemical Industries o p y r i Union polymers, vinyl acetate, synthetic resin waste water chemically Simin River g h t
Senawang vinly acrylic, emulsion treated A
surfactant, c t
polyvinly alcohol a p p l i Electric and Electronic Products e s
t o
t
NAITO, Senawang paper cartons, transistors, waste chemicals untreated Simin, River h e
acetone silicon diode acetone, etc u s e
ABE HOICME paper carton ss, electronic waste oil untreated Simin River o f
iron, brass, copper casings, press t h i trichloro ethylene buttons s
d o c
Metal Industries ; u m e
taps, showers, acid water untreated Simin River n
DORF, senawang metal components, t .
glue, lubricants N a n y
Seremban Metal, metal components wire nails waste water chemically Simin River a n
Senawang treated g
T e c
Food Processing Industries h n o l Chung Weng, caramel, salt, soya sauce waste water untreated Simin River o g i
Senawang soya bean, wheat, bottled chilles c a
vinegar l
flour, flavouring, U
saccharin n i v e r Senawang Edible fuel oil edible oil waste water untreated Simin River s i t y
Oil Sdn. Bhd. L i
Senawang b r a r y Table 2 (Conbd.)
Factory/location Major raw Material Water Effluent Disposal Receiving material input output source A
type method stream T T E
Poultry Related Industries N T I O
FAMA, Senawang chicken meat processed meat waste water untreated Simin River N :
T
Far East Food Pro- chicken feathers, poultry by h waste water untreated Simin River e
ceasing, Senawang dried fish products S i n g
Tjjnber Processing Industries a p o r United Plywood and wood, glues e plywood waste water untreated Senawang River C
Saw Mills Sdn. Bhd., o p
Senawang y r i g h t
Rubber Based Industries A c t
Dunlopillo Malaysia string frame, coco— foam rubber waste water primary Linggi River a p
Sdn. Bhd., nut fibres, plastics, with chemicals sedimentation p l
t i Seremban wood slots rubber, pond e s
t
chemicals o
t h e
Dunlop Sports sulphur, zinc oxide, golf balls waste water untreated Simin River u
surlyn, latex cut, s e
polybutadiene o f
t h i Industrial Rubber P.V. latex, calcium rubber gloves waste water — Simin River s
d
nitrate, HC1 o c u Slaughter House m e
T n t .
Veterinary Dept. pig and cattle meat waste water untreated Simin River N a n y
Miscellaneous Industries a n g
HSR Johnson china clay, lime ceramic wall waste water untreated Simin River T e
tiles c stone, silica sand, h n
sodium trypoly- o l pho'sphate o g i c a
wd.-iLe water untreated Simin River l
Pantile cumunt, colour U
oxide, sand, zinc ridges with colour n i oxide v chip e r s i t Seremban fibre duraband glues, corrugated paper waste water untreated Simin River y
L
cartons i containers ink, laminar film b r a r y Table 2 (Contd.) A
Factory/location Major raw Material Water Effluent Disposal Receiving T T E
material input output source type method stream N T I O
Palm Oil Mills N :
T h
Guthrie Palm Oil fresh fruit crude palm oil Siliau River waste water two stage Siliau River e
S i Processing Sdn. brunches and palm kernel and sludge anaerobic n g a
lagoons p o
Gan Teng Slew fresh fruit crude palm oil Kundor Besar waste water anaerobic Kundor Besar r e
Realty Sdn. Bhd., brunches River . and sludge and facul- River C
Rantau tative ponds o f p y r i g h t
A c t
a p p l i e s
t o
t h e
u s e
o f
t h i s
d o c u m e n t .
N a n y a n g
T e c h n o l o g i c a l
U n i v e r s i t y
L i b r a r y Table 2 (Contd.)
r Factory/location Major raw Material Water Effluent Disposal Receiving A T
output source type method stream T material input E N
Rubber Factories T I O N :
Lam Seng Manufactur- cup lumps SMR 10 Bating Penar waste water untreated Batang Penar T
ing Sdn. Bhd. rubber sheets h SMR 20 River River e
Seremban S i n g
Nam Hong Trading cup lumps SMR 20 Linggi River waste water untreated Linggi River a p
Sdn. Bhd. Seremban tree laces SMR 5 sheet SMR 10 C 4 cuttings SMR 50 o p y r i Lee Rubber Co. Sdn. cup lumps SMR Linggi River waste water anaerobic £ Senawang River g h t Bhd., Seremban tree laces USS (s.s.) facultative A ponds. Half c t treated and a p ' / recycled. p l i e s SMR 10 Simin River waste water treated Simin River t Seremban Estate cup lumps o ,S^R CV t Factory, Gadut tree laces h e River latex u s e Malaysian Rubber field latex Latex cone- Kayu Ara waste water untreated Kayu Ara River o f Development Corp t entrate skim River h i oration (MARDBC), s d Ulu Ara o c u Gan Teng Siew Realty field latex SMR Kundor Besar ^waste water anaerobic Kundor Besar m e Sdn. Bhd., Rantau n River pond River t . N a Sua Grensing Estate field latex n y Factory, Rantau RSS — waste water untreated Linggi River a n g Siliau Estate field latex T e crep Siliau waste water untreated Siliau River c Factory, Siliau h n o l Atherton Estate field latex o g i Factory, Siliau latex cone- pond and waste water treated Siliau River c a l entrate JKR water U Tampin-Linggi Estate field latex n i RSS, SMR, USS — -waste water untreated Linggi River v Factory, Linggi e r s i t latex cone- Rembau River waste water recycled Linggi River y Kota Trading, field latex L i Rembau entrate skim, after b r a SMR treatment r y ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library Table 3 : Estimated amounts of pollutants generated in the Linggi River Basin. Vo1ume BOD mVday kg/day Rubber processing 39,132 2,125.0 Oil palm processing 503.2 368.9 Industries 2, 179 3,584 Domestic sewage 24,550 10,550 * ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library Table 4 : Mean values of chemical parameters analysed between January 1903 - January 1984 in the Linggi River Basin (pll - median values are given). Li nggi river ( s. s ) Parameter Stations 1 2 3 4 5 pH 6.04 5.60 5.34 5.46 5.21 Specific conductivity umho/cm 25°C 29.30 32.73 4 3.08 86.77 78.46 Dissolved oxygen (mg/1) 8.27 7.46 4.05 2.08 4.65 BOD (mg/1) 1.17 1.38 9.12 11.87 7.12 Permanganate value (mg/1) 1.42 2.46 5.72 6.088 4.90 Orthophosphate (mg/1) 0.006 0.012 0.222 0.323 0.122 Ammonia-nitrogen (mg/1) 0.13 0.12 1.0 5.17 2.64 Nitrite-nitrogen (mg/1) 0.0002 0.0004 0.003 0.004 0.011 Nitrate-nitrogen (mg/1) 0.07 0.10 0.17 0.35 1.06 Silica (mg/1) 18.66 18.52 17.18 13.76 12.08 Alkalinity (mg/1) 25.91 30.73 42.36 81.00 46.09 Chloride (mg/1) 3.34 3.53 7.75 9.90 9.40 SIMIN RIVER Parameter Stations 6 7 3 , pH 5.31 5.94 5.17 Specific conductivity umho/cm 25°C 24.10 422.00 71.60 Dissolved oxygen (mg/1) 8.01 3.65 6.44 BOD ((mg/1) 1.03 13.98 5.83 Permanganate value (mg/1) 0.39 9.20 2.09 Orthophosphate (mg/1) 0.014 0.24 0.04 Ammonia-nitrogen (mg/1) 0.147 12.56 0.603 Nitrite-nitrogen (mg/1) 0.001 0.003 0.007 Nitrate-nitrogen (mg/1) 0.17 0.21 0.87 Silica (mg/1) 12.10 9.67 10.61 Alkalinity (mg/1) 16.60 101.00 24.60 Chloride (mg/1) 5.69 26.44 11.25 KUNDOR RIVER Parameter ^. Stations 5 10 11 12 pH 5.37 6.38 6.05 5.48 Specific conductivity unho/cm 25°C 135.20 690.0 212.00 64.86 Dissolved oxygen (mg/1) 3.72 3.41 6.19 6.78 BOD (mg/1) 21.36 117.71 12.31 6.48 Permanganate value ((mg/1) 4.30 24.29 8.62 5.76 Orthophosphate (mg/1) 0.087 2.19 0.403 0.119 Ammonia-nitrogen (mg/1) 9.70 30.17 2.95 0.76 Nitrite-nitrogen (mg/1) 0.001 0.083 0.024 0.003 Nitrate-nitrogen (mg/1) 0.19 1.30 2.51 0.544 Silica (mg/1) 7.87 — 10.70 8.24 Alkalinity (mg/1) 128.0 519.60 183.50 38.43 Chloride (mg/1) 10.80 55.30 28.00 10.61 REMBAU RIVER Parameter Stations 13 14 15 PH 5.16 5.13 5.03 Specific conductivity umho/cm 25°C 49.36 42.33 45.83 Dissolved oxygen (mg7l) 6.05 7.16 6.58 BOD (mg/1) 2.63 2.52 2.75 Permanganate value (mg/1) 5.63 3.69 3.19 Orthophosphate (mg/1) 0.015 0.019 0.043 Ammonia-nitrogen (mg/1) 0.381 0.30 0.31 Nitrite-nitrogen (mg/1) 0.001 0.002 0.003 Nitrate-nitrogen (mg/1) 0.130 0.35 0.53 Silica (mg/1) 17.06 12.13 r0.47 Alkalinity (mg/1) 42.40 34.00 24.18 Chloride (mg/1) 6.22 6.22 7.80 ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library Table 5 Domestic water treatment facilities, production capacities, and water sources in the Linggi River Basin Treatment facility Capacity Source (million litres/day) Linggi Water Treatment Plant 63.7 Linggi River Terip Water Treatment Plant 42 Terip River Pantai Water Treatment Plant 17 Batang Penar River Pedas Water Treatment Plant 7.3 Pedas River ' Table 6 Treatment processes in the Linggi and Pantai Water Treatment Plants Pantai Water Treatment Plant 1. Clarification 2. Chlorination Linggi Water Treatment Plant 1 . Screens 2. Discarding facilities ^. 3. Cascade aerators 4. Sedimentation 5. Sludge blanket type tank 6. Rapid sand filters 7. Chemical treatment - lime - alum - sodium silicofluoride - chlorine \. Fig. 1 The hydrological cycle A T T E N T I O N : T h e S i n g a p o r e C o p y r i g h t A c t a p p l i e s t o t h e u s e o f t h i s d o c u m e n t . N a n y a n g T e c h n o l o g i c a l U n i v e r s i t y L i b r a r y ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library Fig. 2 : The Linggi River Basin, Negri Sembilan ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library \Z2 Rubber |;:;;j;:|| Oil poim |,.»t j Podi Miscellaneous crops j^-fi'jj Forest reserves •-~-r Swamp Settlement and industrial 2 4 6 8 10 12 14 16 Kilometres C* Fig. 3 : Landuse in the Linggi River Basin, Negri Rembilan ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library Rubber mill fe^P^r Polm Oil mill Rubber smoll-holder's processing centre Industries generating water pollution Sawmill Motor and engineering workshop Industrial estate KUALA PILAH Strait of Motacco 8 10 Miles i ' i—r1—i—h r1- 1 1 8 10 12 14 16 Kilometres Fig. 4 : Major sources of pollution in the Linggi River Basin, Negri Semb i 1 an ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library Fig. 5 : 'Sampling stations for wateX quality analysis with reference to Table 4 ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library Fig. 6 : Profile of water quality parameters at various reaches in the Linggi River Basin, Negri Sembilan. ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library 4 Fig. 7 : Percentage and volume of water wasted during treatment at the Linggi Water Treatment Plant