Water Pollution Sources
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Water Pollution Sources 1. Point Sources - PowerPoint PPT Presentation

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Water Pollution Sources 1. Point Sources Wastewater that are discharged from known sources at an identifiable point. Point source pollution can be reduced or eliminated through proper wastewater treatment prior to discharge. 2. Non-point Sources

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Water Pollution Sources

1. Point Sources

Wastewater that are discharged from known sources at an identifiable point. Point source pollution can be reduced or eliminated through proper wastewater treatment prior to discharge.

2. Non-point Sources

Non-point sources are characterized by multiple discharge points (eg. urban & agricultural runoff). Much of the non-point sources pollution occurs during rain storms. Reduction of non-point source pollution generally requires changes in land use practices.

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Clean rivers

Clean Rivers

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Data from world water commision
Data from World Water Commision

  • 1.4 billion people live without clean drinking water

  • 7 million people die yearly from disease link to water

  • Half of world’s rivers and lakes are badly polluted.

  • 450 million people in 29 countries facing water shortage

  • By 2025, 2.5 billion people will face water shortage

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Condition of rivers
Condition of rivers

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Effect of River Pollution

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Polluted Rivers

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Water source and demand
Water Source and Demand

  • 90% of water supply in Malaysia comes from rivers, streams and reservoirs.

  • Growing demand of water ( population growth and rapid development)

  • Per capita availability of water is decreasing due to river pollution

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Water quality index

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Water pollution

  • Associated with water borne diseases.

  • Sources:

    • Organic wastes

    • Inorganic industrial wastes – more difficult

    • New chemical every year

    • Heat and dissolved oxygen

    • Municipal waste

    • Agricultural Waste

    • Erosion and sedimentation

    • Oil and grease (ships, etc.)

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  • Rich in water resources

  • Rainfall – 3,000 mm/ yr.

  • 98 % water use – rivers and streams

  • Others – groundwater (but 90% - freshwater res.)

  • Annual average availability - 28,400 m3 per capita.

  • > 150 rivers in Malaysia

  • Usage – 5 billion m3 (domestic and industry)

  • Total – 25 billion m3 (storage) in dams.

  • Future: National water vision(2025)– Integrated Water Resources Mngt. (IWRM) – policies, various aspects of socio-economic dev. /conservation of the environment.

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National river water monitoring program
National River Water Monitoring Program

  • The Dept of Environment (DOE) – started in 1978

  • Since 1995 – contracted out to Alam Sekitar Malaysia Sdn.Bhd. (ASMA) (privatization).

  • 2003 – 926 stations located within 120 river basins in M’sia – monitored.

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  • 1996: DOE suspended licenses (4 palm oil mills, 4 rubber factories, later revoked – repeated violations).

  • 23 of 27 rivers in Selangor heavily polluted (sewage, industrial waste, animal waste, heavy metals (1997).

  • Johor, Penang (also high in industrial water pollution).

  • October 1997 – 2 treatment plants in Cheras – shutdown (diesel contamination; high ammonia levels). Sources: industrial and quarry activities.

  • July 2005 – Opening of new Bukit Tagar (near Sungai Selangor ) landfill (8,000 tonnes per day wth. 4,200 m3 leachate per day) may pollute water supply; controversial EIA (July 25,2005).

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Main issues and challenges

  • Institutional and legal issues – inter-agency, National Water Resources Council (NWRC), outdated, redundant, ambiguous laws.

  • Increased competition for water – urban growth, new dams (env’al costs).

  • Increased flooding problems – 9% flood prone.

  • Environmental degradation – water pollution, > 80 tonnes waste/ day (Klang Valley).

  • Low efficiency of water use – 40-50% efficiency; 1/3 loss before reaching consumer (leaks, illegal connections).

  • Increased expectations of the people - awareness

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Common Water Uses

  • Drinking

  • Cooking

  • Washing

  • Agriculture

  • Aquaculture

  • Power generation

  • Transportation

  • Recreational

  • Aesthetic

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Percolation 50


RAIN (100%)












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Lake pollution
Lake Pollution

  • Differs from river/stream pollution due to physical characteristics of the water mass.

  • Water in streams/rivers is constantly moving thus providing a flushing action for incoming pollutants.

  • However, in lakes, the water does not move very much and is retained for a relatively long period of time.

  • In some cases pollutants discharged into lakes can remain there for many years.

  • Water quality in lakes is largely influenced by the presence of nutrients.

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  • An increase in the rate of incoming nutrients (nitrogen, phosphorus, carbon) and sediments.

  • It is a natural aging process (but can be accelerated by human activities) and can be thought of as an inevitable and continual aging process of a lake.

    Eutrophication stages

  • Oligotrophic

  • Mesotrophic

  • Eutrophic

  • Senescent

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Nutrients as Algal Growth Requirements

1. Carbon

algae can obtain carbon from CO2 dissolved in the water. The largest source of CO2 is from the atmosphere.

2. Nitrogen

usually in the form of nitrate and comes from external sources.

3. Phosphorus

phosphorus in lakes originates from external sources and is taken up by algae in the organic form.

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The process of


This is called …..



Stage 1

Deep, clear, cold nutrient-poor water, with very little aquatic life


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Stage 2

Nutrients and sediment begin to accumulate; increasing populations of aquatic life appear


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Stage 3

Nutrient rich, relatively shallow, warmer water, with much plant growth and other aquatic organisms; algal blooms occur


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Stage 4

Oldest stage of a lake; very shallow; overgrown with emerging rooted plant life


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Eutrophication will kill all animals

and plants in the water





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(Ramsar Convention 1971)

Areas of marsh, peatland, or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh brackish or salt, including areas of marine water the depth of which at low tide does not exceed 6 meters

(Biological definition)

Transition zone between terrestrial and aquatic environments


  • The area must be permanently or seasonally inundated

  • The area must support hydrophytic vegetation

  • Soil in the area must be water logged for a sufficient time to become anaerobic

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Man made lakes, reservoirs


Highland rivers, headwaters

Oxbow lakes

Lowland rivers

Peat swamp forest

Mangrove forest


Mud flats

Shallow inshore waters


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Natural Functions of Wetlands

Climatic effects

- carbon fixation and CO2 balance (photosynthesis)

- rainfall & humidity effects (evaporation & evotranspiration)

Biodiversity functions

- ecosystem diversity

- link between terrestrial and aquatic ecosystem

- high species and population diversity

- highly diverse microbiological activity

Habitat functions

- wildlife habitat

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Natural Functions of Wetlands (cont.)

Hydrological & hydraulic functions

- storm protection

- coastal erosion protection

- water holding capacity (water catchment)

- water supply

Water quality functions

- particulate filteration

- nutrient stripping

- biodegradation of toxic compounds

- heavy metal removal

- wastewater treatment and water quality improvement

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Types of Constructed Wetlands

1. Free water surface system (FWS)

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Types of Constructed Wetlands

2. Subsurface flow system (SFS)

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Treatment Process in Wetland System

1. Biodegradable organic matter removal

Role of wetland vegetation

i. providing support medium for microbial degradation

ii. conveying oxygen for aerobic degradation to occur

2. Solids removal

Settleable solids are removed easily via gravity sedimentation as wetland systems generally have long hydraulic retention time.

Filtering of solids by plant stems

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Treatment Process in Wetland System

3. Nitrogen removal

i. nitrification/denitrification

ii.uptake by plants

4. Phosphorus removal

i. uptake by plants

ii.microbial degradation

iii.adsorption and precipitation onto soil

5. Heavy metal removal

i. precipitation as insoluble metal hydroxides in the aerobic zone of the substratum

ii. uptake into roots, rhizomes and leaves of wetland vegetation.

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