1

Environmental Science & Engineering

CHAPTER 2

ENVIRONMENTAL POLLUTION

2

Environmental Pollution

- An unfavourable alteration of our surroundings.

Types of Pollutants

Biodegradable

Eg: Wood, Leaves and Cotton

Non – Biodegradable

Eg: Plastics, Metals and Glasses.

3

Classification of Pollution

1. Air Pollution

2. Water Pollution

3. Soil Pollution

4. Marine Pollution

5. Noise Pollution

6. Thermal Pollution

7. Nuclear Pollution

4

1. Air Pollution

It is an atmospheric condition where certain substances are present in concentration which can cause undesirable effects on man and his environment.

5

Eg: Gases, Particulate matter and radioactive substance etc.

Gaseous pollutants – SOx, Nox, Cox and VOC

Particulate pollutants – smoke, dust, soot and fume etc.,

Radioactive pollutants – Radon 222, Iodine 131 and Strontium 90.

Sources of Air pollution Natural sources – Volcanic eruption, Forest fires and biological

decay. Man-made sources – Thermal power plants and agricultural

activities.

6

Effects•Human respiratory system has a number of mechanisms for protection from air pollution. •Bigger particles (> 10 micro m) can be trapped by the hairs and sticky muscus lining in the nose.

Pollutant Effect

Aldehydes Irritates nasal and respiratory tracts

Cadmium Damage kidney

Hydrogen Sulfide Irritates eyes, causes nausea, bad odour

7

Control of Air pollution• Using non conventional energy • Planting more trees • Reducing vehicle exhausts • Using less polluting fuels • Using mass transport • Removal of particulate matter using electrostatic

precipitator, cyclone filter etc. • Removal of NOX from vehicle exhaust

8

2. H2O Pollution

The alteration in physical, chemical and biological

characteristics of water which may cause harmful effects on

human and aquatic life.

9

Classification of Water pollutants

1. suspended matter

2. thermal discharge

3. pathogens (bacteria, fungi, protozoa fungi)

4. natural organic pollutants

5. synthetic organic pollutants

6. inorganic chemicals

7. radioactive waste, oil, sediments

Causes• Point source - Ex: flow of water pollutants from sewerage system,

industrial effluent etc. • Non-point source - Ex: agricultural land (pesticides, fertilizers,

mining, construction sites).

10

Effects

1. Objectionable colour and odour is unacceptable and unsuitable for drinking and other purposes.

2. highly turbid and very hard water is unpleasant to drink, food processing

3. acid and alkaline water cause serious health problem

4. water borne infectious enteric disease like typhoid, cholera, dysentery are the predominant health hazard arising from drinking contaminated water

5. radioactive pollution enter human body through food and get accumulated in thyroid gland, liver, bones and muscles

11

6. biodegradable waste deplete D O in the receiving stream, affect the flora cause creates anaerobic conditions

7. non biodegradable waste and pesticides travel the food chain and ultimately reach human where they accumulate in fatty tissues

8. thermal discharge in stream depletes D O

9. Industrial effluents result in addition of poisonous chemicals such as arsenic, mercury, lead may reach human body through contaminated food

12

Control measures

1. lay down standard for a. drinking water

b. disposal of waste water into water course/sewer/land

2. monitoring

3. treatment a. domestic treatment • screening • sedimentation • filtration, pH adjustment • disinfection

b. waste water treatment • preliminary treatment • primary treatment • secondary treatment • advanced treatment

13

3. Soil Pollution

The contamination of soil by human and natural activities

which may cause harmful effects on living beings.

14

Causes• Industrial waste • Urban waste • Agricultural practices • Radioactive pollutants • Biological agent

Effects• Affect human health • Affect soil fertility • Reduce soil productivity • Cause abnormalities

Control measures

• Properly collect solid waste • Microbial degradation • Recovery of products from waste • For methane generation, use cattle dung • For biogas generation, use biodegradable organic waste

15

4. Marine Pollution

The discharge of waste substances into the sea resulting in

harm to living resources, hazards to human health, hindrance

to fishery and impairment of quality for use of sea.

16

Causes• waste disposal • oil spill • thermal pollution (plants located nearby coastal areas) • ship breaking activities • aquaculture practices • nuclear test conducted in seas and oceans

Effects• disturb entire aquatic or marine ecosystem • oil has suffocation effect on most aquatic animals • smaller animals can be caught in oil envelope and die • thermal

17

• Pollution may increase the temp. of water and DO may be

depleted which causes danger.

• Oil promotes anaerobic conditions by preventing diffusion of

oxygen from air

• Disposal of radio active wastes cause chronic, acute and genetic

damage

• Affect sensitive flora and fauna

• Loss of buoyancy

• Affect phytoplankton, zooplankton, algal species, coral reefs,

fish, birds and mammals.

18

Control measures

• Ban to dump the toxic, hazards waste and sewage sludge. • Prevent sewer overflows • Minimize coastal developmental activities • Oil ballast should not be dumped into sea.

19

5. Noise Pollution

The unwanted, unpleasant or disagreeable sound that

causes discomfort for all living beings.

Types of Noise

1. Industrial Noise

2. Transport Noise

3. Neighbourhood Noise

20

Effects

1. Physiological effects

Headache increase in the rate of heart beat, pain in heart, emotional disturbances, hearing loss.

2. Annoyance

A noise is said be annoying if the exposed individual or groups of individuals reduce the noise avoid or leave the noisy area if possible. Both loudness and annoyance increase with increasing sound levels.

3. Recently it has been reported that the blood also thickened by excessive noise

21

3. Recently it has been reported that the blood also thickened by excessive noise

4. Impulsive noise also causes psychological and pathological disorders.

5. Ultrasonic sound can affect digestive respiratory cardiovascular system and semi circular canals of internal ear.

6. It causes muscle to contract leading to nervs breakdown, tension etc.

22

Control measures

Source Control

1. Modification of source such as acoustic treatment to machine surface designed changes limiting the operational timings.

2. Oiling: Proper oiling will reduce the noise from the machine.

3. Transmission path intervention:

Containing the source inside a sound insulating enclosure, construction of noise barrier or provision of sound absorbing material along the path.

23

4. Planting of trees:

Planting of trees like neem, tamarind, coconut etc near schools hospitals reduce the noise to the extent of 8 to 10 db.

5. Selection of machinery:

Careful selection of machine tools and equipments to be used may help to lower the noise levels in machine shop.

24

Area Permissible noise level (dB)

Day Night

Industrial 75 70

Commercial

65 55

Residential 55 45

Silent Zone 50 40

Sounds and their decibel scale: 1. Rocket engine – 180 dB 2. Jet plane take off – 150 dB 3. Threshold of pain – 140 dB 4. Recorded music (max) – 130 dB 5. Construction works, news paper

press – 100 dB 6. Motor cycle – 90 dB 7. Ordinary conservation – 70/80 dB 8. Air conditioning unit/ Light traffic – 60 dB 9. Normal living room – 50 dB

25

6. Thermal PollutionPollution due to heat which changes the physical and

chemical properties of the water that affects man,

animals and the aquatic system.

Source / Causes:

1. Industrial waste water

2. Nuclear power plant

3. Domestic sewage

4. Hydro electric power plant

5. Coal fire power plant

26

Effects• Reduction in dissolved oxygen• Increase in Toxicity• Interference with biological activities• Interference with reproduction• Direct mortality• Food storage for fish.

Control measures of thermal pollution• Cooling towers - This is used as a coolant wet cooling tower, dry

cooling tower.• Cooling ponds and spray ponds.• Artificial lakes – The heated effluents can be discharged into the

lake at one end and the water for cooling purposes from the other end.

27

7. Nuclear Hazard

The radiation hazard in the environment comes from ultraviolet, visible, cosmic rays and micro wave radiation which produces genetic mutation in man.

28

Causes

I) Natural causes• Solar rays • Radio nuclides in earths crust • Environmental radiation

II)Anthropogenic causes• Medical X-rays • Radio isotopes • Nuclear test • Nuclear installations • Nuclear reactor

29

Effects• Causes skin burns, loss of teeth, vomiting anemia • Blood cancer • Brain damage

Control measures• Radiation exposure protection • Radiation contamination protection • Controlled area • Disposal of radioactive waste

30

Solid Waste Management

Management of solid waste is very important in order to minimize the adverse effects of solid wastes.

31

Types of solid wastes

1. Urban wastes

Sources– Domestic wastes – Food waste, Cloth, Waste paper.– Commercial wastes – Packing material, cans, bottles, polythene.– Construction Wastes – Wood, concrete debris.– Bio medical wastes – Anatomical wastes, infectious wastes.

2. Industrial wastes

Sources– Nuclear power plants – generates radioactive wastes– Thermal power plants – produces fly ash in large quantities

3. Chemical industries

Produces large quantities of hazardous and toxic materials

32

EFFECT OF SOLID WASTE

1.Biodegradable materials in the disposed municipal waste undergo decomposition. This produces foul smell and breeds various types of insects which spoil land well.

2. Industrial waste containing toxic metals and hazardous waste affect soil characteristics.

3. Toxic substances name percolate into the ground and contaminates the ground water.

4. Burning of some industrial waste or domestic waste produces furan, dioxins and poly chlorinated biphenyls which are harmful to human beings.

33

Control measure

Solid Waste generation

Collection of waste

Transportation

Storage

Segregation of waste

Disposal (Landfill, Incineration and Composting)

34

Disposal Methods1. Landfills• dumping• spreading the solid waste on the ground • Compacting it and then covering it with soil at suitable intervals• After 2 or 3 years solid waste volume shrinks by 25-30% and the

land is used for parks, roads and small buildingsMerits Simple and economical. Segregation is not required. Natural resources are returned to soil and reclyed .Converts low lying, marshy waste land into usefull areas. De-Merits Large area needed. Bad odour. High transportation cost. Sources of mosquito, flies. Insecticides and pesticides are to be applied at regular intervals. Causes fire hazard due to methane formation in wet weather.

35

2. INCINERATION • In this method the municipal solid wastes are burnt in a

furnace called incinerator. • The heat produced in the incinerator during burning is used as

steam power for generation of electricity through turbines.• The temperature maintained is about 700 ˚ C and increase to

1000˚ C when electricity is to be generated Advantages1. Requires little space 2 .Hygienic point of it is safest. 3. Incinerated plants of 300 tons per day capacity generate 3 MW of power.

Disadvantages1. Capital and operational cost is high. 2. Needs skilled persons. 3. Formations of smoke, dust and ash causes air pollution.

36

3. COMPOSTING• In this method bulk organic waste is converted in to manure by

biological action. • Dumped in underground trenches in layer of 1.5 meters and is

finally covered about 20 cm and left for decomposition.• Within two to three days biological action starts .• The temperature of the compost increases by 75˚C.• The refuse is converted to a brown coloured powder known

as humus and is used in agricultural fields.• The compost contain N,P and other minerals.

Advantages•Recycling occurs. •Number of industrial solid wastes can also be treated by this method.

37

Role of an individual in prevention of pollution

• Plant more trees• Help more in pollution prevention than pollution control• Use water, energy and other resources efficiently• Purchase recyclable, recycled and environmentally safe products• Reduce deforestation• Remove NO from motor vehicular exhaust• Use of eco friendly products.

Think globally; Act locally

38

Jnurm CIMSWMLCoimbatore’s Integrated Municipal Solid Waste Management Limited

Solid waste generated• India – 960 Million

Tonnes• Coimbatore -

39

40

41

Pollution Case Studies

1. Bhopal gas tragedy: (Air Pollution)

Pesticide factory-Union Carbide- corporation leak large volume of methyl iso cyanate –atmosphere Bhopal- India-midnight on December 3,1984-city- change-gas chamber-within a week 10,000 people died – 1000 people turned blind-lakhs of people still continue to suffer various diseases

2. Chernobyl Disaster : (Nuclear pollution)

Occur at Chernobyl in USSR 28 th April,1986-the reactor exploded- result of uncontrolled nuclear reactions-radioactive fuel spread out in to the surrounding areas –killed at least 20,000 people-damage to soil, water and vegetation around 60 km.

42

Disaster Management

• Disaster is a sudden calamity which brings misfortune and miseries to humanity.• It is a perceived natural event which threatens both life and property.

Types of Disaster management1. Natural disaster: Floods, Cyclones, earth quakes,

landslides. etc.,2. Man made disaster: Accidents, pollutions, fire accidents, bomb blasts.

43

Flood

Submergence of waste areas of land under water for many days in continuation

Causes

1.Heavy rainfall 2. Sudden Snow melt3. Clearing of forest for agriculture 4. Industries increase the value and rate of water discharge after a storm

44

Effects:

1. Damage to building and property

2. Soil erosion is the major loss of agriculture

3. Any product submerged by flood water cannot be rescued

Control measures:

1. Building wall prevent spilling out the flood water over flood pains

2. advance meteorological information will prevent flood damage

3. reduction of run off by increasing infiltration through appropriate forestation

45

Earthquake

Earthquake is the motion of the ground surface caused by wave motion starting from a focal point

Causes

1. Underground nuclear testing 2. Volcanic eruption 3. Pressure of manmade dams, reservoir and lakes 4. movements of plates of earth

46

Effects:

1. Cause Tsunami

2. Deformation of ground surface

3. In hilly and mountain areas may cause land slides which damage the settlement and transport system

4. Depending on the severity of the quake collapses house and people died in 1000 eg. Earthquake in Bhuj town

Control measures:

1. Government can inform the earthquake prone zone and caution residence

2. building should be designed to withstand tremors

47

Cyclone

Cyclone is meteorological phenomena intense depressions forming over the open oceans and moving towards the land .

48

Effects:

1. Depends on the intensity of the cyclone

2. Damage to human life crops roads, transport, communication could be very heavy

Control measures:

1. planting more trees on hostel areas

2. construction of dams

3. Radar system is used to detect cyclone eg.Cyclone in AP

49

Landslide

The movement of earth materials like coherent rock, mud, soil and debris from higher region to lower due to gravitational pull is called landslide.

Causes

1. Earthquake, shock, vibration 2. Deep water ground mining 3. movement of heavy vehicles on the

unstable sleepy region

50

Effects:

1. Increase erosion of soil

2. block the roads

3. damage the houses, crop yield, life stock

Control measures:

1. Planting of deep rooted vegetation

2. Encouragement for construction of bridges water ways

3. Create national parks, sanctuaries biosphere.

e.g.land slides in U.P

51

Questions ?