Basic Environmental Engineering and Pollution Abatement

Pollution types and sources

DR. PRASENJIT MONDAL

CHEMICAL ENGINEERING

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 CONTENTS

➢Pollution, pollutants and their types

➢Sources of pollution/pollutants
➢Water pollution
➢Air pollution
➢Soil pollution
➢Pollution from industries

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➢Pollution, pollutants and their types
• Pollution is the introduction of contaminants/harmful materials into the natural
environment that cause adverse change. These harmful materials are called pollutants.
• Pollution can take the form of chemical substances or energy, such as noise, heat or light.
• The pathway of pollution is the way the pollutant moves from the source, enters into the
environment, and finally how it reaches the human body or other recipient.
• Pollutants can be either naturally occurring contaminants such as volcanic ash or may be
created by human activity, such as trash or runoff produced by factories, domestic,
commercial, agricultural ands forest sectors
• There are two types of pollution-
✓ Natural pollution
✓ Man made pollution
• Pollutants may be in the form of gas, liquid, solid as well as energy and damage the
quality of air, water, and land.
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➢Sources of pollution/pollutants
Natural pollution/pollutants : Produced through natural phenomena, calamities etc. ; for
example, geogenic arsenic in ground water
Man made pollutants : Produced through human activities; can be classified as follows:
❖Point and non point sources
❖Domestic, industrial, agricultural and transport activities
Gaseous pollutants
Gaseous air pollutants are emitted from various natural sources, such as volcanoes and forest
fires. However, anthropogenic emissions of some gases may be greater than the natural ones
and are increasing because of population growth and industrialization.
Liquid pollutants
Liquid pollutants usually come from liquid waste, which includes human excreta (both faeces
and urine), industrial wastewaters and other forms of waste from water-using activities.
Factories generate liquid waste from activities related to washing in the manufacturing
process, cleaning objects and chemical mixing, wastes
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➢Sources of pollution/pollutants contd..
• Sewage is a mixture of human excreta from water-flushed toilets and other wastewater from
houses and businesses. Sewage and human waste from overflowing septic tanks and latrines
are frequent sources of pollution
• Urban run-off can contain a lot of organic matter. This may come from open defecation or
inappropriate handling of organic wastes produced from households and businesses.
• Organic matter includes anything that is derived from living organisms, such as human and
animal wastes, decaying plants and food

• Solid waste is any solid material that is assumed not to be useful and is therefore thrown
away. Factories, businesses and households produce different kinds of solid waste such as
paper, plastics, metals, chemicals in solid form, pieces of cloth or food and animal remains
Sometimes you faecal matter is discarded with solid waste, which adds to the problems.

• Noise pollution means unacceptable levels of noise in work, residential and recreational
places
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➢Sources of pollution/pollutants contd..
Point sources are identifiable points or places that you can easily locate. An example is a
diesel truck that produces visible black exhaust fumes from its tailpipe. Liquid waste released
from a pipe into a river is another example
A non-point source (also known as ‘diffuse pollution’) is one where it is difficult to identify
the exact origin of the pollution. A good example is floodwater that washes all types of waste
from the land (possibly including faecal matter) into a river. In this situation it is difficult to
identify the individual or household or establishment that has caused the water pollution
Point Non point
source of source of
industrial pollution due
to runoff of
pollution
soil and
along the
fertilizer
Calumet
during a
River rainstorm
Source- U.S. Environmental Protection Agency Source- Wikipedia –Nonpoint source pollution

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➢Sources of pollution/pollutants contd..

• Point Sources
➢ Municipal WW Well defined Easier to
origin easily treat/regulate
➢ Industrial WW measured
➢ Tributaries more constant

• Non-point Sources
➢ Untreated sewage Diffuse origin
Difficult to
➢ Agricultural runoff more transient
treat/regulate
often dependent
➢ Urban & Suburban Runoff on precipitation
➢ Groundwater

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➢Sources of pollution/pollutants contd..
The pathway between source and recipient can take several different forms depending on the
type of pollutant. Primary recipients for pollution are water, air, and soil. Pollutants usually
reach humans through the consumption of contaminated and polluted water and food, and
breathing polluted air.
Once released into the environment, the worst effects of many pollutants are reduced by one
or more of the following processes:
•Dispersion – smoke disperses into the air and is no longer noticeable away from the source.
•Dilution – soluble pollutants are diluted in the water of a river or lake.
•Deposition – some suspended solids carried in a river settle (are deposited) on the river bed.
•Degradation – some substances break down (degrade) by natural processes into different,
simpler substances that are not polluting.
In each case the effect is to reduce the concentration of the pollutant.
There are some persistent pollutants which remain intact when released into the environment
because they do not break down by natural processes.

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➢Sources of pollution/pollutants contd..

POINT SOURCES NON-POINT SOURCES

POLLUTANT MUNCIPAL SEWAGE INDUSTRIAL WASTE AGRICULTURAL RUNOFF URBAN RUNOFF

BOD ✓ ✓ ✓ ✓
Nutrients ✓ ✓ ✓ ✓
Pathogens ✓ ✓ ✓ ✓
Suspended solids ✓ ✓ ✓ ✓
Salts ✓ ✓ ✓
Toxic metals ✓ ✓
Toxic organics ✓ ✓ ✓
Heat ✓ ✓
Major pollution sources for fresh and saline waters
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 ➢Water pollution Environmental Risk Assessment and Remediation, (2017) Volume 1, Issue 3

Major sources of water pollution • Water pollution is characterised by the presence of

i. Domestic sewage excess physical, chemical or biological substances that
ii. Industrialization change the qualities of the water and are capable of
iii. Population growth causing harm to living organisms.
iv. Pesticides and fertilizers • Polluted water should not be used for drinking, washing,
v. Plastics and polythene bags bathing or agriculture. If polluted water is used by
vi. Urbanization humans, then it can adversely affect the body in different
vii. Weak management system ways, depending on the type and concentration of
pollutant.
It is reported that 75 to 80% water pollution is caused by the domestic sewage
80% of the world’s population is facing threats to water security • Water pollution can affect
surface water such as rivers
25% pollution is caused by the industries and is more harmful and lakes, soil moisture and
The WHO reports that 80% diseases are waterborne groundwater in aquifers, and
the oceans.
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➢Water pollution contd.. Wastewater and their classification
DOMESTIC ➢ Domestic wastewater
• Black water
• Grey water

WASTEWATER

STROM DRAINS

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Waste water and their classification contd..
Typical composition of untreated domestic waste water
Concentration
Contaminants Low strength (mg/L) Medium strength (mg/L) High strength (mg/L)

Solids, total(TS) 390 720 1230

Dissolved, total (TDS) 250 500 850
Suspended solids(TSS) 120 210 400
BOD, 5 day,20o 110 220 400
TOC 75 140 290
COD 250 500 1000
Total nitrogen (as N) 20 40 70
Total Phosphorus(asP) 4 8 15
Chloride 30 50 100
Sulfate 20 30 50
Alkalinity (as CaCO3) 50 100 200
Grease 50 100 150
Total coliform 106 –107 ( No/100 ml) 107 – 108 (No/100 ml) 107 -109 (No/100 ml)

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Waste water and their classification contd.. Typical composition of landfill leachates
Parameter Acidogenic phase Methanogenic phase
Average Range Average Range
pH 5 4.5 - 5.5 8 7.5 - 9
BOD5 (mg/l) 13000 4000-40000 180 20 – 550
COD (mg/l) 22000 6000-60000 3000 500 – 4500
BOD5/COD 0.58 - 0.06
Sulphate (mg/l) 500 70-1750 80 10 – 420
Calcium (mg/l) 1200 10-2500 60 20 – 600
Magnesium (mg/l) 470 50 - 1150 180 40 – 350
Iron (mg/l) 780 20 - 2100 1.5 3 – 280
Manganese (mg/l) 25 0.3-65 0.7 0.03 – 45
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➢Sources of pollution/pollutants contd.. Common wastewater pollutants

Physical Chemical
• Suspended solids (TSS, • Anions (SO42-,Cl-, F-, PO43-, NO3-, NO2-)
Turbidity (NTU) • Cations (K, Fe, Mn)
• TDS • Hardness
• Conductivity • Salinity (Sodium Adsorption Ratio; Residual
• APHA color Sodium Carbonate)
• Temperature • Heavy Metals (Hg, Pb, Cd, Cr)
• Taste and odour • As (metalloid), F (non-metal)
Biochemical Microbiological
instability • Pathogens
• BOD, COD • Viral particles
• Natural Organic Matter • Prions
• Total Organic Carbon • Biomass, Volatile suspended solids

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➢Air pollution

• Air pollution is defined as the presence of abnormal amounts of chemical constituents in

the air, which are capable of causing harm to living organisms.
• Polluted air may contain particulate matter (such as black soot) and many different gaseous
chemicals such as carbon monoxide, carbon dioxide, nitrogen oxides, sulphur oxides,
ozone, nitrates, sulphates, organic hydrocarbons and many others.
• The most common sources of air include the burning of wood, charcoal and other biomass
fuel by households, small businesses such as bakeries, manufacturing industries, and
vehicles.
• Clean air consists of nitrogen (78% by volume), oxygen (21%) and trace gases (< 1%)

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➢Air pollution contd.. Main cause
•Dust storm and Wildfires:
•Animal and Vegetation: ...
•Volcanic Activity: ...
•Fossil-Fuel Emissions: ...
•Agriculture and Animal Husbandry: ...
•Waste
• Main cause: Combustion
Fuel (C,H,S,N,Pb,Hg,ash) + Air (N2 + O2)
CO2, CO, NOx, SOx, Pb, Hg, SPM, PM10,PM2.5, VOCs

Usage/handling of Chemicals: paint, varnishes, perfumes, CFCs, petrol pumps, etc.

Cement handling, insulation on winding of motors/alternators/transformers etc.

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➢Air pollution contd.. Sources of Particulate Matter
PM10 and PM2.5

India
➢Air pollution contd.. SOx and NOx

• SO2, SO3, SO4-2 formed during • Primarily NO and NO2

combustion of fuel containing sulfur • NO3, N2O, N2O3, N2O4, N2O5 are also
• H2S released is converted to SO2 known to occur

• 10 Tg/yr natural sources • Thermal NOx created by oxidation of

• 75 Tg/yr anthropogenic sources atmospheric N2 when T > 1000 K

• Fuel NOx from oxidation of N in fuel

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➢Air pollution contd..
Lead

• Sources:
– Gasoline and paints (historical)
– metals processing
• Highest air Pb concentrations
– in the vicinity of nonferrous and ferrous smelters, and battery
manufacturers.
➢Soil pollution
• Soil pollution, also called land pollution, is linked to water pollution
• Liquid wastes containing toxic chemicals or pathogenic micro-organisms on the surface of
the land can seep slowly into the soil and may percolate down to contaminate groundwater,
which can affect people using springs or wells in the area
• Possible sources include open defecation, pit latrines or leaking storage containers for
industrial chemicals and wastes
• Solid waste can cause soil pollution. Household waste typically consists mostly of food waste
that will gradually decompose. This produces a bad odour and attracts insects and rats, both
of which contribute to the transmission of disease
• As the waste decomposes it produces a liquid called leachate which trickles down into the
soil. Leachate is a highly concentrated liquid pollutant that may contain toxic chemicals and
pathogenic micro-organisms as well as high levels of organic compounds
• Rainwater falling on, and washing through, solid waste adds to the problem
• Soil pollution also affects agricultural activity and pollute food items

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➢Pollution from industries
Classification of Industries

Industries

Red type Orange Type Green Type

(A:17 + B:47) (25) (55)

Note: The industry which do not fall in any of the above mentioned three categories (i.e.
Red/Orange/Green), decision with regard to their categorization will be taken by a committee
at Head Office level comprising of the Member Secretary and two senior offices of the
Board/Committee
➢ Emission
➢ Effluents
➢ Noise
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 Composition of some industrial wastewater
Industry type Organic load (mg/l) Typical composition of organic compound
Pulp and paper COD: 32000 – 40000 Soaps: 40-45% ; lignin: 35-45%
BOD: 12 000–16 000 Other organics: 10-15%
Distillery COD: 110000–190000 Reducing sugar (g/l): 0.5; Total sugar (g/l): 0.8
BOD: 50000–60000 Total acids (g/l): 3.34; Free amino acids (g/l): 3.18
Melanoidin for colour Total nitrogen (g/l): 11.0
Sugar COD: 385 – 978 Glucose
BOD: 112 – 225 Fructose
Oil refinery COD:1965, BOD: 685 Oil contents , total solids, phenol
Petrochemicals COD:1500; BOD: 350, Octanol, HCHO, phenol, organic acid, petroleum

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Thanks

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