1. ERT 349 SOIL AND WATER ENGINEERING
Water Quality
At the end of this topic, student should be able to:
Determine the sources of water pollution
Analyze water quality parameter based on water quality standard
Design the water treatment process

3. Outline Introduction to Water Quality Water Pollution Types
Sources of Pollution
Sources categories
Eutrophication
Water Quality Legislation
Water Quality Parameter
Water Quality Treatment

4. Introduction Most of the Earth’s surface is covered with water.
Our bodies, plants & animals are consist about 90% of water.
We can only survive a few days without water.
Water is an essential nutrient for all plants & animals
Water transports nutrients & carries away waste products.
Water cools the body

5. Water Pollution
The presence of a substance in the environment that because of its chemical composition or quantity prevents the functioning of natural processes and produces undesirable environmental and (human) health effects.

6. Types of water pollutant
Sediment
Sewage/Domestic effluent
Pathogen (Water-borne disease)
Organic compound
Inorganic/chemical compound
Radioactive compound
Thermal pollution

7. Sediment
Erosion causes loose soil to enter the waterways
Suspended sediment blocks sunlight to plants and reduces dissolved oxygen.

8. Sewage/ Domestic effluent

9. Sources of pollution 1. Agriculture Fertilizers, animal wastes, etc.
2. Municipal Waste
Sewage, fertilizers, dumping into drainage ditches, etc.
3. Industrial Waste
Chemicals left over from manufacturing, waste products, etc.

10. Pollution sources categories
Point sources
Water pollution can be traced at specific spot through drain, pipe and sewer
Example: Industrial/ domestic treatment plant
Non-point sources
Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry.
Example: Agricultural fertilizer runoff and sediments from construction.

11. Point sources and non-point sources

12. Eutrophication Definition
The enrichment of a lake or pond by inorganic plant and algal nutrients such as phosphorus and nitrogen.
The additional nutrients are food for algae and fish, so the more eutrophic a lake is, the more living organisms it sustains.
When a lake becomes shallower from added sediment, even more plants can grow because the littoral area increases in overall percentage.
Littoral area - the area of the lake that is shallow enough for light to reach the bottom

13. Eutrophication is a natural process that a lake goes through over hundreds to thousands of years.
Eutrophication is also sometimes referred to as lake aging.

15. Water Quality Indicator
Physical
Chemical
Biological

16. Physical indicator
Colour
Taste and Odor
Turbidity
Suspended Solid

17. Colour
May be due to the presence of organic matter, metals (iron, manganese) or highly coloured industrial waste
Aesthetically displeasing

18. Taste and Odour
Mainly due to organic substances, biological activity, industrial pollution
Taste buds in the oral cavity specially detect inorganic compounds of metals like magnesium, calcium, sodium, copper, iron and zinc
Water should be free from objectionable taste and odour.

19. Turbidity Turbidity refers to water clarity.
Caused by suspended matter/sediment
High level turbidity shield and protect bacteria from the action of disinfecting agents
Unit in NTU

20. TSS is the measure of the sediment suspended in the water.
Total Suspended Solid (TSS)
TSS is the measure of the sediment suspended in the water.
TSS is related to turbidity.
Water with high TSS usually has high Total Dissolved Solids (TDS) as well.

21. Organic & Chemical INDICATORpH
Hardness
Alkalinity

22. Organic Dissolved Oxygen (DO)
The amount of oxygen gas dissolved in a given volume of water at a particular temperature and pressure.

23. Organic Biological Oxigen Demand (BOD)
The amount of oxygen required by aerobic microorganisms to decompose the organic matter in a sample of water, such as that polluted by sewage.
When BOD levels are high, dissolved oxygen (DO) levels decrease because the oxygen that is available in the water is being consumed by the bacteria.

24. Organic Chemical Oxygen Demand (COD)
A measure of the capacity of water to consume oxygen during the decomposition of organic matter and the oxidation of inorganic chemicals such as ammonia and nitrite.
Another term that refers to COD is a measure of organic materials in a wastewater in terms of the oxygen required to oxidize the organic materials chemically.

25. pH It is the measure of hydrogen ion concentration Neutral water pH-7
Acidic water has pH below 7
Basic water has pH above 7

26. Hardness
Capacity of water for reducing and destroying the lather of soap
It is total concentration of calcium and magnesium ions
Temporary hardness – Bicarbonates of Calcium and Magnesium
Permanent hardness – Sulphates, chlorides and nitrates of calcium and magnesium

27. Hardness 0 – 50 mg/l - soft 50 – 150 mg/l - moderately hard
150 – 300 mg/l - hard
300 above very hard
Surface water is softer than ground water
Causes encrustations in water supply structures
Note: heat can change hardness -> forms scale on boilers, coffee pots

28. Alkalinity Capacity to neutralise acid
Presence of carbonates, bi-carbonates and hydroxide compounds of Ca, Mg, Na and K
Alkalinity = hardness, Ca and Mg salts
Alkalinity > hardness - presence of basic salts, Na, K along with Ca and Mg
Alkalinity < hardness – neutral salts of Ca & Mg present
Units expressed as CaCO32-

29. Iron One of the earth’s most plentiful resource
High iron causes brown or yellow staining of laundry, household fixtures
Metalic taste, offensive odour, poor tasting coffee
Cause iron bacteria

30. Chloride Causes Dissolution of salt deposit Discharge of effluents
Intrusion of sea water
Not harmful to human beings
Regarding irrigation – most troublesome anion

31. Ammonia
Ammonia is produced by the decay of organic matter and animal waste.
Ammonia is toxic to most aquatic life, especially at high pH.
Bacteria readily convert ammonia to nitrate (a plant nutrient)
Ammonia is a form of nitrogen and part of the Nitrogen Cycle.

32. Ammonia
Nitrogen Cycle

33. Nitrate Increasing level of nitrate is due to
Agricultural fertilizers, manure,animal dung, nitrogenous material ,sewage pollution
Cause blue baby diseases to infants

34. Phosphate
Phosphate’s concentrations in clean water is generally low; however, phosphorus is used extensively in fertilizer and other chemicals.
The primary sources of phosphates to surface water are detergents, fertilizers, and natural mineral deposits.
High levels of phosphate can over stimulate the growth of aquatic plants and algae.
This in turn, will cause high DO consumption and death to fish and many aquatic organisms.

35. Fluoride Occurs naturally
Long term consumption above permissible level can cause –
dental flurosis (molting of teeth)
Skeletal flurosis
Remedy
Deflouridation
Mixing Fluride free water
Intake of vitamin C,D, calcium, antioxidants

36. Arsenic Occur in ground water from arseniferous belt
Industrial waste, agricultural insecticide
High arsenic causes various type of dermatological lesions, muscular weakness, paralysis of lower limbs, can also cause skin and lung cancer

37. Heavy Metals Present as mineral in soil and rocks of earth
Human activities
Battery – Lead & Nickel
Textile - Copper
Photography – Silver
Steel production – Iron

38. Pesticides These chemicals are very complex.
Effect on aquatic organism
Cancer
Birth defects
Blood disorder
Nervous disorder
Genetic damage

39. BIOLOGICAL
Bacteria
Most bacteria are important in nutrient and other organic cycles.
Excess nutrients cause algal blooms.
As algae die and decay, the high bacterial load rapidly consumes dissolved oxygen.

40. Certain types of bacteria indicate animal and human waste pollution.
Escherichia coli are coliform bacteria found in the intestines of warm-blooded organisms. Most strains are harmless but one E. coli strain can cause severe diarrhea and kidney damage.

41. Water Quality Legislation

42. Water Quality Legislation
Interim National Water Quality Standard (DOE, 1986)
Surface Water
Marine Water
Drinking Water
Sources:
Environmental Quality Act, 1974
Environmental Quality (Sewage and Industrial Effluent) Regulation, 1979
Standard A
Standard B

43. Table 1. Water Use Classes in the National Water Quality Standards
Uses
CLASS I
Conservation of natural environment water supply 1 - practically no treatment necessary. Fishery 1 - very sensitive aquatic species
CLASS IIA
Water Supply II - conventional treatment required Fishery ll - sensitive aquatic species
CLASS IIB
Recreational use with body contact
CLASS III
Water Supply lll - extensive treatment required Fishery lll - common, of economic value, and tolerant species livestock drinking
CLASS IV
Irrigation
CLASS V
None of the above – Dead river

44. National Water Quality Standards For Malaysia
PARAMETER
UNIT
CLASS I
IIA
IIB
III IV V
Ammoniacal Nitrogen
mg/l
0.1
0.3
0.9
2.7
> 2.7
Biochemical Oxygen Demand 1 3 6 12
> 12
Chemical Oxygen Demand 10 25 50
100
> 100
Dissolved Oxygen 7
5 - 7
3 - 5
< 3
< 1 pH -
6 - 9
5 - 9
Colour
TCU 15
150
Electrical Conductivity*
µS/cm
1000
6000
Floatables N
Odour
Salinity %
0.5 2
Taste
Total Dissolved Solid
500
4000
Total Suspended Solid
300
Temperature °C
Normal + 2 °C
Turbidity
NTU 5
Faecal Coliform**
count/100 ml
400
5000 (20000)a
Total Coliform
5000
50000
> 50000
Notes * = At hardness 50 mg/l CaCO3 # = Maximum (unbracketed) and 24-hour average (bracketed) concentrations N = Free from visible film sheen, discolouration and deposits
Sourse : EQR2006

45. PARAMETER LIMITS OF EFFLUENT OF STANDARD A AND STANDARD B
Parameter
Unit
Standard A
Standard B
(i) Temperature °C 40
(ii) pH Value
(iii) BOD5 at 20°C
mg/l 20 50
(iv) COD
100
(v) Suspended Solids
(vi) Mercury
0.005
0.05
(vii) Cadmium
0.01
0.02
(viii) Chromium, Hexavalent
(ix) Arsenic
0.10
(x) Cyanide
(xi) Lead
0.5
(xii) Chormium, Trivalent
0.20
1.0
(xiii) Copper
(xiv) Manganese
(xv) Nickel
(xvi) Tin
(xvii) Zinc
(xviii) Boron
4.0
(xix) Iron (Fe)
5.0
(xx) Phenol
0.001
(xxi) Free Chlorine
2.0
(xxii) Sulphide
0.50
(xxiii) Oil and Grease
Not detectable 10

46. Water Treatment

47. Water Treatment
Water treatment is a process of removing contaminants from raw water to produce water that is chemically and bacteriological safe for human consumption. 
The water must also be aesthetically acceptable, free from apparent turbidity, colour, objectionable taste and odour. 

48. Water Treatment Process
Source: SAJ

49. Water Treatment Process
The conventional treatment plant comprises of the following processes:
Screening
Floating debris such as woods, leaves, aquatic plants and others are screened at the intake by coarse screen. After screening, the denser suspended matters are removed by allowing water to pass through chamber where it settles down to the bottom.

50. 2. Aeration
Raw water pumped from the intake is mixed with air at the aerator.
The aeration process provides oxygen from atmosphere for the oxidation of dissolved iron and manganese to their insoluble form thus enable their removal.
The process also helps in the removal of taste and odour.

51. 3. Coagulation / Flocculation
Coagulants, usually alum, are added leading to the formation of microscopic particles in water. This is followed by gentle agitation causing small particles in the water to collide and combine to become bigger settleable flocs.

52. 4. Sedimentation
The flocs are allowed to flow through the sedimentation tank as uniform as possible for long enough period for them to settle. The clarified water will be collected from the top.
If the flocs are light, another process will apply. In this process minute air bubbles are introduced. The flocs will stick to the air bubbles and float to the top. The clarified water will be collected from the bottom.This process is called Dissolve Air Flotation.

53. 5. Filtration
The settled water then goes through filters where the fine particles and bacteria are trapped. The clean water then goes to the clear water tank. The filters are backwashed regularly through a combination of agitation by air and water to ensure efficient operations.

54. 6. Disinfection /pH Adjustment
In the clear water tank, the water is disinfected to destroy microorganism still remain in water after filtration. Gaseous chlorine or chlorine compound are normally used for disinfections. The pH is adjusted using lime or soda ash.  

55. 7. Clear Water Tank
Treated water will be collected and kept in Clear Water Tank for distribution.
8. Water Supply Distribution
From the clear water tank at the water treatment plant, treated water is pumped through long pipelines to balancing reservoirs with sufficient height for distribution by gravity to service reservoirs in various demand centers. In areas where water is unable to be supplied by gravity, secondary pumping systems will be introduced. 

57. Alternative water quality treatment
Reverse Osmosis (RO)
Membrane Treatment
UV System
Filtration system
Ultrafiltration
Biofiltration
Natural Treatment
Wetland

58. Thank You