A Technical Paper presented by Samson O. Ojoawo, MNSE, Ph.D at a meeting of the Nigerian Society of Engineers in September, 2017

1. ENVIRONMENTAL POLLUTION: COMMON
SOURCES AND REMEDIES IN THE
NIGERIAN CONTEXT
A TECHNICAL PAPER
DELIVERED BY
Samson Olakunle OJOAWO, MNSE, COREN Regd., Ph.D
Associate Professor of Civil Engineering, Ladoke Akintola University of Technology Ogbomoso
@
THE NIGERIAN SOCIETY OF ENGINEERS (NSE) OGBOMOSO
BRANCH MONTHLY GENERAL MEETING
Wed 27th SEPTEMBER, 2017

2. Definitions
“Environmental Pollution is the
introduction by man into the
environment of substances or
energy liable to cause hazard to
human health, harm to living
resources and ecological
systems, damage to structures
or amenity, or interference with
legitimate use of the
environment”
- Royal Commission’s 10th Report

3. Definitions cont’d
Pollution
The introduction of contaminants into the natural
environment that cause adverse change
Pollutants
Substances introduced to the environment which
adversely affect the usefulness of our resources
- (FEPA, 1991)
Pollutants are components of pollution, foreign
substances/energies or naturally occurring
contaminants

4. Factors determining the
severity of a pollutant
•Chemical nature
•Concentration
•Persistence

5. Some background information
on environmental pollution
• Industrial revolution gave birth to modern
environmental pollution
• Emergence of great factories and
consumption of immense quantities of coal
gave rise to unprecedented air pollution
• Large volume of industrial chemical discharges
contributes to the growing load of untreated
wastes

6. • Pollution began to draw major public attention in
the United States between the mid-1950s and
early 1970s, when Congress passed the Noise
Control Act, the Clean Air Act, the Clean Water
Act and the National Environmental Policy Act.
• Growing evidence of local and global pollution
and an increasingly informed public over time
have given rise to environmentalism and the
environmental movement, which generally seek
to limit human impact on the environment
• Pollution can take the form of chemical
substances or energy, such as noise, heat or light

8. General forms of pollution
• Air pollution: the release of chemicals and
particulates into the atmosphere. Gaseous
pollutants include CO, SO2, NOx, CFCs
• Light pollution: includes light trespass, over-
illumination and astronomical interference
• Littering: the indiscriminate throwing of
inappropriate man-made objects, un-removed, onto
public and private properties
• Noise pollution: which encompasses roadway noise,
aircraft noise and industrial noise, as well as high-
intensity sonar.

9. • Soil contamination: chemicals are released by
spill or underground leakage. Most significant soil
contaminants are hydrocarbons, heavy metals,
herbicides, and pesticides
• Radioactive contamination: results from 20th
century activities in atomic physics, such as
nuclear power generation and nuclear weapons
research, manufacture and deployment
• Thermal pollution: a temperature change in
natural water bodies caused by human influence,
such as use of water as coolant in a power plant.

10. • Visual pollution: presence of overhead power
lines, motorway billboards, scarred landforms
(as from strip mining), open storage of trash,
municipal solid waste or space debris
• Water pollution: discharge of wastewater
from commercial and industrial waste
(intentionally or through spills) into water
sources
• land pollution: involves the contamination of
soil against its intended uses

11. Proper location of resources to minimize water and
land pollution

12. Fundamental/Common Environmental
Pollution Sources
• Water
• Air
• Noise

14. Environmental pollution
management hierarchy
Prevention
Minimization
Treatment/disposal
/abatement
Most favoured
Ojoawo, 2013

15. Water Pollution
• Contamination of water by foreign matters
• Foreign matters include micro-organisms,
chemicals, wastes, sewage etc
• Contaminants render the water unfit for intended
uses
• Rivers and streams pollution by chemical
contaminants is critical in 21st century

16. The occurrence of water on earth

17. S.N CHARACTERISTICS ACCEPTABLE EXCESS
PHYSICAL
1 Turbidity(NTU) 2.5 10
2 Colour (Platinum cobalt scale) 2.5 5
3 Temperature 100C 150C
4 Taste & Odour Unobjectionable
CHEMICAL
1 pH 6.5 8
2 Total solids(mg/l) 500 1500
3 Total hardness (as CaCO3) mg/l 200 600
4 Chloride(as CL) mg/l 200 1000
5 Sulphate(as SO4) mg/l 200 400
6 Fluorides(as F) mg/l 1.0 1.5
7 Nitrates(as NO3) mg/l 45 45
8 Calcium (Ca) mg/l 75 200
9 Magnesium (asMg) mg/l 30-120 150
10 Iron (asFe) mg/l 0.1 1.0
TOXIC MATERIALS
1 Arsenic (as As ) mg/l 0.05 0.05
2 Cadmium(as Cd) mg/l 0.01 0.01
3 Lead (as Pb) mg/l 0.1 0.1
4 Mercury (total Hg) mg/l 0.001 0.001
5 Polynuclear aromatic hydrocarbons(PAH) 0.2µ g/l 0.2µ g/l
BACTERIOLOGICAL
Coliform count per 100ml of water sample 0 0
DRINKING WATER STANDARDS (Ministry of Urban Development, INDIA)

18. Classification of chemical
pollution of water
• Point pollution: sources which are specifically
identifiable e.g factories, refineries, outfall
pipes, etc
• Non- point pollution: those not possible to
precisely define e.g agricultural operation
runoff, mining runoff, sewage drain fields etc

19. Key water pollutants
• Leachate, sewage, wastewater and other oxygen
demanding wastes – carbonaceous organic
matters, decomposition leading to oxygen
depletion
• Infectious plants – nutrients stimulating aquatic
plant growth, depletes DO when decaying
• Exotic organic chemicals – pesticides, detergents
etc
• Petroleum – from oil spillage

20. Leachate emanating from waste dumps
causing groundwater pollution
Leachate sampling for analysis

21. A safe solid waste disposal via conversion to organic fertilizer

22. Key water pollutants cont’d
• Inorganic minerals – salts, chemical compounds
• Faecal pollution – from human excreta
• Sediments – eroded soil and mineral particles,
floodwater from croplands, unprotected /bulldozed
urban areas
• Radioactive substances – from mining and refining
wastes like those of Uranium and Thorium, nuclear
power plants
• Heat – discharge of cooling water by factories and
power plants

23. Effects of water pollution
• Water-borne diseases like cholera, typhoid fever, dysentery, polio etc
• Nitrate salts causing blue baby syndrome leading to death; water-
borne diseases arising from faecal pollution etc
• Cadmium from fertilizer sludge of crops leading to acute diarrhoeal
disorder and liver/kidney damage
• Eutrophication of lakes – artificial enrichment with nutrients causing
abnormal plant growth, caused by chemical fertilizer runoff
• Acid rain – atmospheric pollution with SO2, NOx etc
• Wildlife mortality – drinking of industrial effluents

24. Some identified threats to potable water and the
environment in Nigeria

25. Chemical and microbial analysis of selected ‘potable’ water samples

26. Control and Treatment of water pollution
• Locating water sources upstream and far away
from sources of pollution
• Treatment (Domestic and Conventional)
Domestic water treatment
 Boiling
 UV Sterilizing unit
 Chlorination/Ozonization
Conventional water treatment
 Screening of debris
 Subjection to Unit Processes

27. Stainless steel reverse
osmosis water purifier
Sun Sun 13W UV Sterilizer
9W UV Sterilizer
Wall-mounted UV Sterilizer
Some domestic water treatment units/kits

28. Conventional water treatment Unit Processes

29. Air Pollution
“Presence in the outdoor atmosphere of one or more
contaminants such as dust, fumes, gas, mist, odour,
smoke or vapour in quantities or characteristics and
duration such as to be injurious to human, plant or
animal life or to property or which unreasonably
interfere with the comfortable enjoyment of life and
property”
– Engineers Joint Council

30. Proportion of molecules in clean air
Molecule Symbol Proportion by
Volume
Nitrogen N2 78.1%
Oxygen O2 20.9%
Argon Ar 0.93%
Carbon dioxide CO2 360 ppm (0.03%)
Neon Ne 18 ppm
Helium He 5 ppm
Methane CH4 1.7 ppm

31. Common Air pollutants
Pollutant Symbol/representat
ion
Source
Carbon Monoxide CO Automobile, 80%
emission
Oxides of Sulphur SO2 and SO3 Coal, fuel burning
etc
Hydrocarbons HCs Unburn fuels, C2H6,
C5H12 etc
Oxides of Nitrogen NO and NO2 Combustion process
Particles VOCs Particulate matters
in air

32. Sources of indoor air pollutants
• Poor building ventilation, sprays (insecticides, anti-
reptiles, etc
• New building materials (Polymers, PVC, paints,
vanishes, asbestos, rugs etc)
• Microbial contaminants (viruses, bacteria, fungi at
bathrooms and kitchens)
• Sick building syndrome (bioallergens from A/C,
formaldehydes from insulation)
• Odours from domestic activities (NH3 from
perspiration, mercaptans from tobacco smoke etc)
• Firewood cooking – incomplete combustion of wood
emitting soot

33. Effects of air pollution
• Lung damage in humans (particles < 5 microns
penetrate upper respiratory system)
• Malfunctioning of gastro-intestinal system
• Systemic pesticides/herbicides may penetrate the skin
and damage blood stream
• CO from incomplete combustion may deplete or react
with oxygen in blood (heamoglobin) circulation, trigger
cadio-vascular diseases, and result into death
• NO2 irritates the lungs, causes bronchitis and
pneumonia, may also trigger asthma

34. • O3 reduces lung function, causes coughing,
sneezing, chest pain and pulmonary congestion.
• Objectionable odour, tastes
• Corrosive or chemical effects of F, H2S Nox etc on
objects (exterior of buildings, monuments and
etching of car glass)
• Human skin damage, spoilage of fabric and
leather dresses
• Reduction in visibility of air traffic (soot and
smoke impair sights)

35. • Phyto-toxicological effect of fluorine on flower or fruit
is recognized once it exceeds 0.3 µg/m3
• Excessive H2F, SO2, H2S etc clog the leave stomata,
reducing CO2 intake and adversely affecting
photosynthesis
• Cattle grazing on vegetation contaminated with F may
develop fluorosis
• Arsenic poisoning leading to vomiting and irregular
pulse may be caused by ingesting of leaves sprayed
with insecticides
• On the environment at large, air pollution may cause
acid rain, ozone depletion, and global warming
(the attached video clip refers)

36. en House Effect , Ozone La

37. Key precursors to air pollution

38. Primary and Secondary air pollutants

39. Air pollution control measures
• Natural self cleansing by the environment
(dispersion, gravitational settling, absorption,
rainout, adsorption
• Dilution – for point-source air pollution, factories
may use high rise chimneys, emitting it far high
above the GL
• Green vehicle usage - replacement of burning
fuel by electricity or solar energy e.g electric cars
by Nissan (Jan 2018, leaf 2, to travel 400kms
without charge and costs about $30,000),
General Motors, Tesla etc

40. Air pollution control measures cont’d
• Legislation on use of new vehicles/equipment
only up till a reasonable period before being
banned
• Renewable energy sources like solar powered
electricity generation for homes, public facilities
etc
• Installation of engineering device controls like
cyclone collectors, wet scrubbers, electrostatic
precipitators etc to reduce particulate matters

41. Cyclone air collector
Water Scrubber
Wet Scrubber

42. Cyclone Dust
Collector
Electrostatic Precipitator
ESP

43. Air pollution control measures cont’d
• Regular maintenance of industrial plants and
equipment
• Prevention of open burning of wastes (e.g tyre
recycling) and e-transaction to minimize
refuse

44. Recycling of
tyres into
seats

45. Noise Pollution
• Noise: “The unwanted sound pollutant, which produces
undesirable physiological and psychological effects in an
individual, by interfering with one’s social activities like work,
rest,recreation,sleep etc”
• Noise level is measured in decibels (dB)
• Whispering records nearly 5 dB on noise meter
• Normal conversation is about 10 – 15 dB

46. Common sources of noise
S/N Source of Noise Noise level (in dB)
1 Air traffic
(jet/propeller
aircraft)
90 – 110
2 Rail traffic 90 – 110
3 Heavy road
traffic(highway)
80 – 90
4 Medium road traffic
(main street)
70 – 80
5 Light road traffic
(side street)
60 – 70
6 Two wheelers and
cars
80 – 82

47. Common sources of noise cont’d
S/N Source of Noise Noise level (in dB)
7 Passenger or
commercial
vehicles
85 – 90
8 Industrial (rotating,
reciprocating
machines etc)
60 – 95
9 Miscellaneous
(blaring of
loudspeakers,
sirens, market
noise, church and
temple bells,
mosques call to
prayer, phone ear
piece
varying intensities
depending on the
closeness of the
source

48. Effects of noise pollution
• Annoyance/Irritation
• Diseases (insomnia, high blood pressure, high
pulse rate, headaches, nausea, etc)
• Communication interference
• Hearing loss (tinnitus and deafness)
• Inactivity or dullness in animals (e.g deers, birds
etc)

49. Noise control and abatement
• Promulgation of acts and laws restricting noise
generation and levels
• Renewable energy sources like solar powered
electricity generation for homes, public facilities etc
• Proper town planning techniques e.g into residential
(adequate set-backs), industrial, commercial (at
downwind sides), green belt areas etc

50. Noise control and abatement cont’d
• Imbibing better design technologies e.g in generating
plants (noise-proof/silent), a/c, refrigerators, fans, grinders
etc
• Construction of walls on both sides of roads and rails or
tunnels for highway and railway noise
• Raising of thick and high vegetation barriers along major
roads
• Building with acoustic door and window glasses
• Regular maintenance of vehicles, machines, aircrafts, etc

51. Conclusion/General Recommendations on
environmental pollution control
• Use of household water sterilizing units, routine laboratory
analysis and regular disinfection of ‘our potable’ water
• Locating septic tanks, grave/tomb upstream and farther
from water sources, not closer than 70 ft
• E-transaction (receipts, invitation cards, programmes,
minutes, paperless meetings, e-pictures, e- greeting cards,
projected lectures, soft copy notes/slides, electronic
billboard adverts rather than paper posters etc)
• Promoting the development of electric cars with zero
emissions
• Encouragement of renewable power sources like solar, wind,
etc, Noise proof generators

52. References (selected)
• Colls, J. (1997) Air pollution: An Introduction. Chapman and Hall, London
• Encyclopaedia of Occupational Health and Safety (2017) International Labour Office
• Garg, S.K (2009) Environmental Engineering Vol II: Sewage disposal and Air pollution
Engineering.
• Google Search Engine (2017) Environmental Pollution
• Microsoft Encarta Reference Library (2002)
• Ojoawo, S.O (2013) Unpublished lecture notes on Environmental Pollution -CVE 519,
Department of Civil Engineering, University of Osun, Osogbo, Nigeria
• Ojoawo, S.O, Udayakumar, G and Shetty, S (2014) Potability assessment of notable water
sources in Nitte community, India. IISTE Civil and Environmental Research Journal,
U.S.A. 6 (11): 65-71, ISSN 2224-5790 and ISSN 2225-0514
• Spiegel J . And Maystre, L.Y (2014) Environmental pollution control and prevention, The
Environment Francias, Chapter 55

53. THE END