Water Pollution Sources 1. Point Sources

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.

Environmental Engineering BAA3613

Environmental Engineering BAA3613

Clean Rivers

Environmental Engineering

Data from World Water Commision1.4 billion people live without clean

drinking water7 million people die yearly from disease

link to waterHalf of world’s rivers and lakes are badly

polluted.450 million people in 29 countries facing

water shortageBy 2025, 2.5 billion people will face water

shortage


Condition of rivers


Effect of River

Pollution


Polluted Rivers




MAP


Water Source and Demand90% 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


WATER QUALITY INDEX


WATER POLLUTIONAssociated with water borne diseases.Sources:

Organic wastes Inorganic industrial wastes – more difficultNew chemical every yearHeat and dissolved oxygenMunicipal wasteAgricultural WasteErosion and sedimentationOil and grease (ships, etc.)


MALAYSIARich in water resourcesRainfall – 3,000 mm/ yr.98 % water use – rivers and streamsOthers – 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.


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.


Cases: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).


MAIN ISSUES AND CHALLENGES 1. Institutional and legal issues – inter-agency,

National Water Resources Council (NWRC), outdated, redundant, ambiguous laws.

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

3. Increased flooding problems – 9% flood prone.

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

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

6. Increased expectations of the people - awareness


Common Water Uses- Drinking- Cooking- Washing- Agriculture- Aquaculture- Power generation- Transportation- Recreational- Aesthetic


PERCOLATION(50%)

RIVER

SURFACE RUNOFF

(20%

CONDENSATION

PRECIPITATION/

RAIN (100%)

HYDROLOGIC CYCLE

EVAPORATION

(30%)

EVAPOTRANSPIRATION(40%)

GROUNDWATERFLOW (10%)

Environmental Engineerin

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.


EUTROPHICATION- 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 stages1. Oligotrophic2. Mesotrophic3. Eutrophic4. Senescent


Nutrients as Algal Growth Requirements

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

2. Nitrogenusually in the form of nitrate and comes from external sources.

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


Th

e p

rocess o

fEu

trop

hic

ati

on

This is called …..

…..EUTROPHICATION

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

Oligotrophic


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

Mesotrophic


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

Eutrophic


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

Senescent


Eutrophication will kill all animals

and plants in the water

BEFORE EUTROPHICATION

AFTER EUTROPHICATION

nutrients

nutrients

Lake

Wetlands


WETLANDS

(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

Criteria1. The area must be permanently or seasonally

inundated2. The area must support hydrophytic vegetation3. Soil in the area must be water logged for a

sufficient time to become anaerobicEnvironmental Engineering

ManMan made lakes, reservoirs

Highland rivers, headwaters

Oxbow lakes

Lowland rivers

Peat swamp forest

Mangrove forest

Estuaries

Mud flats

Corals

Shallow inshore waters


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 habitatEnvironmental Engineering

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


Types of Constructed Wetlands1. Free water surface system (FWS)



Types of Constructed Wetlands

2. Subsurface flow system (SFS)




Treatment Process in Wetland System

1. Biodegradable organic matter removalRole of wetland vegetationi. providing support medium for microbial degradationii. conveying oxygen for aerobic degradation to occur

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

Filtering of solids by plant stemsEnvironmental Engineering

Treatment Process in Wetland System3. Nitrogen removal

i. nitrification/denitrificationii.uptake by plants

4. Phosphorus removali. uptake by plantsii.microbial degradationiii.adsorption and precipitation onto soil

5. Heavy metal removali. precipitation as insoluble metal hydroxides in the aerobic zone of the substratumii. uptake into roots, rhizomes and leaves of wetland vegetation.


Documents

Water Pollution Sources 1. Point Sources