Water Pollution, BOD,COD, Eutrophication, Oligotrophication

1. Dr.AB Jadhav, SSAC, SOILS 509
Water Pollution
 Introduction and definition
 Water Impurities
 Sources of pollution
 Effects of Sewage Water
 BOD, COD Eutrophication
 Physical water pollutants
Dr.A.B. Jadhav,
Assistant professor
Soil Science and Agricultural Chemistry
College of Agriculture, Pune

2. Dr.AB jadhav SSAC, SOILS-509
Water Pollution
As per the ‘Prevention and Control of Pollution act 1974’
Water pollution is
‘the adding to water of any substance, or the changing of water’s
physical, chemical and biological characteristics in any way which
interferes with its use for legitimate purpose
Or
Water pollution means such contamination of water or such alteration
of the physical, chemical or biological properties of water or such
discharge of any sewage or trade effluent or of any other liquid,
gaseous or solid substance into water/weather directly or indirectly as
may or is likely to create a nuisance or render such water harmful or
injurious to public health or safety or to domestic, commercial,
industrial, agricultural or other legitimate uses or to the life and health
of animals or plants or aquatic organisms

3. Dr.AB jadhav SSAC, SOILS-509
Water Impurities
Dissolved
Gases like H2S, CO2,
N2 or NH3
Minerals like salts
of Ca, Mg and Na
Suspended
Sand, silt, clay
organisms, spores
OM

4. Dr.AB jadhav SSAC, SOILS-509
These are natural impurities derived from the atmosphere,
catchment area and the soil but are in such a low concentration
that they do not pollute the water normally, rather than their
presence is sometimes essential for maintaining the potable and
other useful properties of water
Polluted water are
 Turbid
 Not pleasant
 Bad smell
 Not suitable for bathing
 High BOD
 High COD
 OM content high
Further these waters also harmful to cause diseases and spread
also like typhoid, dysentery, cholera etc

5. Dr.AB jadhav SSAC, SOILS-509
Sewage water/industrial
waste water
(MIDC and River)
Excess use of
fertilizers/Agricultural
waste, pesticide residue
etc.
Physical pollutants
(Heat, thermal ash, dust,
hot water oil spills)
Oxygen demanding
waste
Organic and inorganic
waste/Excess irrigation
water use
Sources of Water Pollution

6. Dr.AB jadhav SSAC, SOILS-509
Sources of Water Pollution
A. Sewage and other oxygen demanding wastes which
contain decomposing organic matter and pathogenic
agents.
B. Industrial wastes contains toxic agents ranging from
metal salts to complex synthetic organic chemicals
C. Agricultural wastes comprises fertilizers, pesticides
and bioacids
D.Physical pollutants like thermal pollutants and
radioactive substances

7. Dr.AB jadhav SSAC, SOILS-509
A. Sewage and other oxygen demanding wastes which contain
decomposing organic matter and pathogenic agents.
Sewage: Defined as the water borne waste derived from
home/domestic waste/and animal/food processing plants and also
includes human excreta, soaps.
Water pollution is caused by uncontrolled dumping off wastes of
village, towns and cities into ponds, rivers or streams.
If the quantity of sewage received by a water body is small, it is
decomposed by the aerobic bacteria in a short time-termed as self –
regulating mechanism for recycling of wastes quickly
But if the contamination level is higher, the self purifying activity of
the water body is lost and water becomes unfit for human
consumption and other domestic uses.

8. Dr.AB jadhav SSAC, SOILS-509
A major ingredient of most detergents is phosphate. The phopshate
combines and inactivates ions such as Ca so that they can not react
with and disable the dirt dissolving molecules.
Such water (NO3 and PO4) rich – supports luxuriant growth or blooms
of algae
Effects of sewage water
Depletion of
oxygen content
Stimulation of
algal growth
Spreading
infectious
diseases

9. Dr.AB jadhav SSAC, SOILS-509
Depletion of oxygen content
Caused by aerobic bacteria :
OM decomposition
Quantity of O2 utilized by bacteria in
degradation of organic substances is
called biological oxygen demand (BOD)
On an average basis, the demand for oxygen…. BOD value is
proportional to the amount of organic waste present in water
BOD is used as a measure of waste strength and act as an indicator of
degree of pollution
Reduction in the oxygen results is an increase in anaerobic bacteria

10. Dr.AB jadhav SSAC, SOILS-509
Biological Oxygen demand (BOD) Chemical Oxygen demand (BOD)
Amount of O2 used for biochemical
oxidation by microorganisms in a unit
volume of water. Generally developed
for five days at 20oC
Amount of O2 required by organic matter in a
sample of water for its oxidation by a strong
chemical oxidant and is expressed as ppm of O2
taken from a solution of KMnO4 in two hours.
BOD value approximates the amount of
oxidisable organic matter and therefore
used as a measure of degree of water
pollution and waste strength
This value is a poor measure of strength of
organic matter as oxygen is also consumed in the
oxidation of inorganic matter such as nitrates,
sulphates reduced metal ions and also some
organic materials such as benzene, pyridine and
few other cycling organic compounds are not
oxidized by this test
BOD values are useful in process design
and loading calculation.
It is also used for measuring treatment
efficiency and operation, stream
pollution control and also used to
evaluate the self purification mechanism
of water
It is very important parameter in management
and design of the treatment plants because of its
rapidity in determination. COD values are taken
as basis for calculation of efficiency of treatment
plants for discharging industrial/domestic
effluents in various kinds of water
Types of microbes, pH, presence of
toxins, reduced mineral matter and
nitrification processes are the factors
influence the BOD
Presence of toxins and other such unfavorable
conditions for the growth of microbes do not
affect COD values

11. Dr.AB jadhav SSAC, SOILS-509
Stimulation of Algal Growth
Stimulation of algal growth and also a shift in the algal flora to the
blue-green algae, leading to production of obnoxious blooms,
floating scum's or blankets of algae results into a phenomenon
known as EUROPHICAION
Biological decomposition of such algal masses in turn leads to further
oxygen depletion
In a poorly oxygenated condition with increase CO2 fishes and other
animal die.

12. Dr.AB jadhav SSAC, SOILS-509

13. Dr.AB jadhav SSAC, SOILS-509

14. Dr.AB jadhav SSAC, SOILS-509

15. Dr.AB jadhav SSAC, SOILS-509

16. Dr.AB jadhav SSAC, SOILS-509
Difference between Oligotrophic and Eutrophic lakes
Lakes have changed little since
the time of their formation …i.e.
called geological they are young
These lakes are geologically old as
they have changed a lot since their
formation
Poor in nutrients Rich in nutrients (NO3 and PO4)
Low primary productivity High primary productivity
Deep basin and clean water Shallow basin and turbid with
unpleasant taste and odour
Algal blooms are formed very
rarely
Rich in algal blooms
No severe O2 depletion Dissolved O2 is low
High O2 demanding aquatic
population
High O2 demanding species are
replaced by carp and other
organisms, even edible fresh fish
water

17. Dr.AB jadhav SSAC, SOILS-509

18. Dr.AB jadhav SSAC, SOILS-509

19. Dr.AB jadhav SSAC, SOILS-509

20. Dr.AB jadhav SSAC, SOILS-509
Industrial wastes contains toxic agents ranging
from metal salts to complex synthetic organic
chemicals
 Important Characteristics of industrial waste
water
 Toxic effects of water pollutants
 General effects of discharged waste water into
water ways

21. Dr.AB jadhav SSAC, SOILS-509
Important Characteristics of Industrial Waste Water
Acid manufacture Low pH
Beet sugar High BOD
Coal Washery Low pH, High suspended solids/H2SO4 and FeSO4 present
Coke manufacturer High suspended solids/NH3, H2S, Phenol and oils
Distillery High BOD with brown colour and disagreeable odour, high
dissolved and suspended solids
Electroplating Low pH , High BOD, also contains heavy metals and toxic
substances
Paint manufacturer High BOD, contains synthetic resigns, solvents, pigments
and heavy metals such as aluminum (Al), chromium (Cr)
and lead (Pb)
Petroleum refinery High COD/BOD ratio, also contains hydrocarbons,
alcohols, aldehydes, phenols, oils, metals etc
Tannery High BOD,COD, contains highly dissolved and suspended
solids, oil, grease and heavy metals like Cr
Textile processing High BOD, Suspended and dissolved solids, acids, dyes

22. Dr.AB jadhav SSAC, SOILS-509
Deplete O2/Algal growth/Bad
smell/turbid water/High BOD/No fish
Reduce potbility/Toxic
heavy metals/High COD
Cyanides, phenyles,
mercury, lead, arsenic
Effects of discharged waste water into water ways

23. Dr.AB jadhav SSAC, SOILS-509

24. Dr.AB jadhav SSAC, SOILS-509

25. Dr.AB jadhav SSAC, SOILS-509

26. Dr.AB jadhav SSAC, SOILS-509
3) Spreading Infectious Diseases
Micro-organisms, usually, viruses, bacteria some protozoan's and
helminthes occur in water bodies due to sewage disposal
Common water borne diseases
Organisms Diseases
Viruses Viral hepatitis, poliomyelitis
Bacteria Cholera, typhoid, paratyphoid, dysentery, diarrhea
Protozoa Amoebiosis, giardiasis
Helminthes Round worm, hookworm, thread worm

27. Dr.AB jadhav SSAC, SOILS-509
Degree of water pollution is assessed by the
presence of Escherichia coli number
Heavily Polluted 10,000 L-1
Polluted 10,00 ;L-1
Slightly polluted 100 L-1
Satisfactory quality 10 L-1
Drinking water 3 L-1

28. Dr.AB jadhav SSAC, SOILS-509
4) Physical Pollutants

29. Dr.AB jadhav SSAC, SOILS-509
As per CPCB, New Delhi

30. Dr.AB jadhav SSAC, SOILS-509
As per CPCB, New Delhi

31. Dr.AB jadhav SSAC, SOILS-509

32. Dr.AB jadhav SSAC, SOILS-509

33. Dr.AB jadhav SSAC, SOILS-509

34. Dr.AB jadhav SSAC, SOILS-509
Potentially Toxic heavy Metals

35. Dr.AB jadhav SSAC, SOILS-509

36. Dr.AB jadhav SSAC, SOILS-509

37. Dr.AB jadhav SSAC, SOILS-509

38. Dr.AB jadhav SSAC, SOILS-509

39. Dr.AB jadhav SSAC, SOILS-509

40. Dr.AB jadhav SSAC, SOILS-509

41. Dr.AB jadhav SSAC, SOILS-509

42. Dr.AB jadhav SSAC, SOILS-509
Sewage and other oxygen demanding wastes which contain decomposing organic matter
and pathogenic agents
Water pollution is caused