Envionmental pollution

Pollution
Pollution is the introduction of contaminants into the natural environment that
cause adverse change.
• Pollution can take the form of chemical substances or energy, such as noise,
heat or light.
•Pollutants, the components of pollution, can be either foreign
substances/energies or naturally occurring contaminants
•Pollution is often classed as point source or nonpoint source pollution.
Air pollution
•Air pollution occurs when harmful substances
including particulates and biological molecules are introduced into Earth's
atmosphere.
• It may cause diseases, allergies or death of humans; it may also cause harm to
other living organisms such as animals and food crops, and may damage
the natural or built environment.
• Human activity and natural processes can both generate air pollution.

CLASSIFICATION OF AIR POLLUTANTS
• An air pollutant is a substance in the air that can have adverse
effects on humans and the ecosystem.
• The substance can be solid particles, liquid droplets, or gases.
• A pollutant can be of natural origin or man-made.
Pollutants are classified as primary or secondary.
• Primary pollutants are usually produced from a process, such as ash
from a volcanic eruption.
• Other examples include carbon monoxide gas from motor vehicle
exhaust, or the sulfur dioxide released from factories.
• Secondary pollutants are not emitted directly.
• Rather, they form in the air when primary pollutants react or
interact.
• Ground level ozone is a prominent example of a secondary
pollutant. Some pollutants may be both primary and secondary:
they are both emitted directly and formed from other primary
pollutants.

BIOCHEMICAL EFFECTS OF SOME AIR POLLUTANTS
Substances emitted into the atmosphere by human activity include:
Carbon dioxide (CO2) - Because of its role as a greenhouse gas it has been described as "the
leading pollutant and "the worst climate pollution". Given off by the vehicles running in large number
• Carbon dioxide is a natural component of the atmosphere, essential for plant life and given off by the
human respiratory system.
Sulfur oxides (SOx) - particularly sulfur dioxide, a chemical compound with the formula SO2.
• SO2 is produced by volcanoes and in various industrial processes.
• Coal and petroleum often contain sulfur compounds, and their combustion generates sulfur dioxide.
• Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and
thus acid rain.
• This is one of the causes for concern over the environmental impact of the use of these fuels as
power sources.
Nitrogen oxides (NOx) - Nitrogen oxides, particularly nitrogen dioxide, are expelled from high
temperature combustion, and are also produced during thunderstorms by electric discharge.
• They can be seen as a brown haze dome above or a plume downwind of cities.
• Nitrogen dioxide is a chemical compound with the formula NO2.
• It is one of several nitrogen oxides.
• One of the most prominent air pollutants, this reddish-brown toxic gas has a characteristic sharp,
biting odor.
Carbon monoxide (CO) - CO is a colorless, odorless, toxic yet non-irritating gas.
• It is a product of incomplete combustion of fuel such as natural gas, coal or wood.
• Vehicular exhaust is a major source of carbon monoxide.

Volatile organic compounds (VOC) - VOCs are a well-known outdoor air pollutant.
• They are categorized as either methane (CH4) or non-methane (NMVOCs).
• Methane is an extremely efficient greenhouse gas which contributes to
enhanced global warming.
• Other hydrocarbon VOCs are also significant greenhouse gases because of their
role in creating ozone and prolonging the life of methane in the atmosphere.
• This effect varies depending on local air quality.
• The aromatic NMVOCs benzene, toluene and xylene are suspected carcinogens
and may lead to leukemia with prolonged exposure. 1,3-butadiene is another
dangerous compound often associated with industrial use.
Particulates,- alternatively referred to as particulate matter (PM), atmospheric
particulate matter, or fine particles, are tiny particles of solid or liquid suspended
in a gas.
• In contrast, aerosol refers to combined particles and gas.
• Some particulates occur naturally, originating from volcanoes, dust storms, forest
and grassland fires, living vegetation, and sea spray.
• Human activities, such as the burning of fossil fuels in vehicles, power plants and
various industrial processes also generate significant amounts of aerosols
• Increased levels of fine particles in the air are linked to health hazards such as
heart disease, altered lung function and lung cancer.

Chlorofluorocarbons (CFCs) - harmful to the ozone layer; emitted from products are
currently banned from use.
•These are gases which are released from air conditioners, refrigerators, aerosol sprays, etc.
•On release into the air, CFCs rise to the stratosphere.
• Here they come in contact with other gases and damage the ozone layer.
•This allows harmful ultraviolet rays to reach the earth's surface. This can lead to skin cancer, eye
disease and can even cause damage to plants.
•Ammonia (NH3) - emitted from agricultural processes.
• Ammonia is a compound with the formula NH3.
•It is normally encountered as a gas with a characteristic pungent odor.
•Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as
a precursor to foodstuffs and fertilizers.
•Ammonia, either directly or indirectly, is also a building block for the synthesis of many
pharmaceuticals.
• Although in wide use, ammonia is both caustic and hazardous. In the atmosphere, ammonia
reacts with oxides of nitrogen and sulfur to form secondary particles.
Odours — such as from garbage, sewage, and industrial processes
Radioactive pollutants - produced by nuclear explosions, nuclear events, war explosives, and
natural processes such as the radioactive decay of radon.
Persistent free radicals - connected to airborne fine particles are linked to
cardiopulmonary disease
Toxic metals- such as lead and mercury, especially their compounds.

• We release a variety of chemicals into the atmosphere when we burn the
fossil fuels we use every day. We breathe air to live and what we breathe
has a direct impact on our health.
• Breathing polluted air puts you at a higher risk for asthma and other
respiratory diseases.
• When exposed to ground ozone for 6 to 7 hours, scientific evidence show
that healthy people’s lung function decreased and they suffered from
respiratory inflammation.
• Air pollutants are mostly carcinogens and living in a polluted area can put
people at risk of Cancer.
• Coughing and wheezing are common symptoms observed on city folks.
• Damages the immune system, endocrine and reproductive systems.
• High levels of particle pollution have been associated with higher incidents
of heart problems.
• The burning of fossil fuels and the release of carbon dioxide in the
atmosphere are causing the Earth to become warmer.
• The toxic chemicals released into the air settle into plants and water
sources. Animals eat the contaminated plants and drink the water. The
poison then travels up the food chain – to us.
Effects Of Air Pollution

Environmental Effects of Air Pollution
Along with harming human health, air pollution can cause a variety of
environmental effects:
• 1. Acid rain- is precipitation containing harmful amounts of nitric and
sulfuric acids.
• These acids are formed primarily by nitrogen oxides and sulphur oxides
released into the atmosphere when fossil fuels are burned.
• These acids fall to the Earth either as wet precipitation (rain, snow, or fog) or
dry precipitation (gas and particulates).
• In the environment, acid rain damages trees and causes soils and water
bodies to acidify, making the water unsuitable for some fish and other wildlife.
• It also speeds the decay of buildings, statues, and sculptures that are part of
our national heritage.
• The most important gas which leads to acidification is sulphur dioxide.

• The principal natural phenomena that contribute acid-producing gases to
the atmosphere are emissions from volcano
• Nitric acid in rainwater is an important source of fixed nitrogen for plant life, and is
also produced by electrical activity in the atmosphere such as lightning.
• Acidic deposits have been detected in glacial ice thousands of years old in remote
parts of the globe.
• Human activity
• The principal cause of acid rain is sulfur and nitrogen compounds from human
sources, such as electricity generation, factories, and motor vehicles.
• Electrical power generation using coal is among the greatest contributors to gaseous
pollutions that are responsible for acidic rain.
• The gases can be carried hundreds of kilometers in the atmosphere before they are
converted to acids and deposited.
• In the past, factories had short funnels to let out smoke but this caused many
problems locally; thus, factories now have taller smoke funnels. However, dispersal
from these taller stacks causes pollutants to be carried farther, causing widespread
ecological damage.

Chemical processes
• Combustion of fuels produces sulfur dioxide and nitric oxides. They are
converted into sulfuric acid and nitric acid.
Gas phase chemistry
• In the gas phase sulfur dioxide is oxidized by reaction with
the hydroxyl radical via an intermolecular reaction:
• SO2 + OH· → HOSO2·which is followed by:
• HOSO2· + O2 → HO2· + SO3In the presence of water, sulfur trioxide (SO3) is
converted rapidly to sulfuric acid:
• SO3 (g) + H2O (l) → H2SO4
• (aq)Nitrogen dioxide reacts with OH to form nitric acid:
• This shows the process of the air pollution being released into the
atmosphere and the areas that will be affected.
• NO2 + OH· → HNO3
• Hydrolysis Sulfur dioxide dissolves in water and then, like carbon
dioxide, hydrolyses in a series of equilibrium reactions:
• SO2 (g) + H2O ⇌ SO2·H2OSO2·H2O ⇌ H+ + HSO3
−HSO3
− ⇌ H+ + SO3
2−

Adverse effects-
• Acid rain has been shown to have adverse impacts on forests, freshwaters
and soils, killing insect and aquatic life-forms as well as causing damage to
buildings and having impacts on human health.
• Surface waters and aquatic animals
• Both the lower pH and higher aluminium concentrations in surface water
that occur as a result of acid rain can cause damage to fish and other
aquatic animals.
• At pHs lower than 5 most fish eggs will not hatch and lower pHs can kill
adult fish.
• As lakes and rivers become more acidic biodiversity is reduced.
• Acid rain has eliminated insect life and some fish species, including
the brook trout in some lakes, streams, and creeks in geographically
sensitive areas, such as the Adirondack Mountains of the United States.
• However, the extent to which acid rain contributes directly or indirectly via
runoff from the catchment to lake and river acidity is variable.

2.Greenhouse gases-is a gas in an atmosphere that absorbs and emits radiation within
the thermal infrared range. This process is the fundamental cause of
the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water
vapor, carbon dioxide, methane, nitrous oxide, and ozone.
• Water vapor (H2O)
• Carbon dioxide (CO2)
• Methane (CH4)
• Nitrous oxide (N2O)
• Ozone (O3)
• Chlorofluorocarbons (CFCs)
• Hydrofluorocarbons (incl. HCFCs and HFCs)
• The major atmospheric constituents, nitrogen (N2), oxygen (O2), and argon (Ar), are not
greenhouse gases.
Sources of Greenhouse Gas Emissions-
• Human activities are responsible for almost all of the increase in greenhouse gases in
the atmosphere over the last 150 years.
• The largest source of greenhouse gas emissions from human activities is from burning
fossil fuels for electricity, heat, and transportation.

The primary sources of greenhouse gas emissions are:
• Electricity production- generates the largest share of greenhouse gas emissions.
Approximately 67 percent of our electricity comes from burning fossil fuels, mostly
coal and natural gas.
• Transportation (27 percent of 2015 greenhouse gas emissions) – Greenhouse gas
emissions from transportation primarily come from burning fossil fuel for our cars,
trucks, ships, trains, and planes. Over 90 percent of the fuel used for
transportation is petroleum based, which includes gasoline and diesel.
• Industry (21 percent of 2015 greenhouse gas emissions) – Greenhouse gas
emissions from industry primarily come from burning fossil fuels for energy, as well
as greenhouse gas emissions from certain chemical reactions necessary to produce
goods from raw materials.
• Commercial and Residential (12 percent of 2015 greenhouse gas emissions) –
Greenhouse gas emissions from businesses and homes arise primarily from fossil
fuels burned for heat, the use of certain products that contain greenhouse gases,
and the handling of waste.
• Agriculture (9 percent of 2015 greenhouse gas emissions) – Greenhouse gas
emissions from agriculture come from livestock such as cows, agricultural soils,
and rice production.
• Land Use and Forestry (offset of 11.8 percent of 2015 greenhouse gas emissions) –
Land areas can act as a sink (absorbing CO2 from the atmosphere) or a source of
greenhouse gas emissions. In the United States, since 1990, managed forests and
other lands have absorbed more CO2 from the atmosphere than they emit.

• The effectsof Green house gases that can be predicted include:
• more drought and more flooding
• less ice and snow
• more extreme weather incidents
• rising sea level
More drought and more flooding –
• Extra water vapour in the atmosphere falls again as extra rain, which can
cause flooding in other places in the world.
• When the weather gets warmer, evaporation from both land and sea
increases. This can cause drought in areas of the world where the
increased evaporation is not compensated for by more precipitation.
• In some regions of the world this will result in crop failure and famine
especially in areas where temperatures are already high. The extra water
vapour in the atmosphere will fall again as extra rain, which can cause
flooding in other places in the world.

Less ice and snow
• Towns and villages that are dependent on melt water from mountain
areas may suffer drought and lack of domestic water supply.
• Worldwide, glaciers are shrinking rapidly at present. Ice appears to be
melting faster than previously estimated. In areas that are dependent on
melt water from mountain areas, this can cause drought and lack of
domestic water supply.
More extreme weather incidents-
• The warmer climate will probably cause more heat waves, more violent
rainfall and also an increase in the number and/or severity of storms.
Rising sea level-
• Sea level rises because of melting ice and snow and because of the
thermal expansion of the sea (water expands when warmed). Areas that
are just above sea level now, may become submerged.
• In countries with large areas of coastal lowland there will be a dual risk of
river floods and coastal flooding, which will reduce the area for living and
working.

3. Global Warming- referred to as climate change, is the observed century-scale rise in
the average temperature of the Earth's climate system and its related effects
• Global warming occurs when carbon dioxide (CO2) and other air pollutants and
greenhouse gasses collect in the atmosphere and absorb sunlight and solar radiation that
have bounced off the earth’s surface.
• Normally, this radiation would escape into space—but these pollutants, which can last for
years to centuries in the atmosphere, trap the heat and cause the planet to get hotter.
That's what's known as the greenhouse effect.
• The burning of fossil fuels to make electricity is the largest source of heat-trapping
pollution, producing about two billion tons of CO2 every year.
• Coal-burning power plants are by far the biggest polluters.
• The second-largest source of carbon pollution is the transportation sector, which
generates about 1.7 billion tons of CO2 emissions a year.
• The earth’s ocean temperatures are getting warmer, too—which means that tropical
storms can pick up more energy. So global warming could turn, say, a category 3 storm
into a more dangerous category 4 storm.
• The impacts of global warming are being felt across the globe. Extreme heat waves have
caused tens of thousands of deaths around the world in recent years. And in an alarming
sign of events to come,
• Antarctica has been losing about 134 billion metric tons of ice per year since 2002. This
rate could speed up if we keep burning fossil fuels at our current pace, some experts say,
causing sea levels to rise several meters over the next 50 to 150 years.

Effects of Global Warming- the consequences of global warming are as
follows-
• Melting glaciers, early snowmelt, and severe droughts will cause more
dramatic water shortages and increase the risk of wildfires .
• Rising sea levels will lead to coastal flooding on the Eastern Seaboard,
especially in Florida, and in other areas such as the Gulf of Mexico.
• Forests, farms, and cities will face troublesome new pests, heat waves,
heavy downpours, and increased flooding. All those factors will damage or
destroy agriculture and fisheries.
• Disruption of habitats such as coral reefs and Alpine meadows could drive
many plant and animal species to extinction.
• Allergies, asthma, and infectious disease outbreaks will become more
common due to increased growth of pollen-producing ragweed, higher
levels of air pollution, and the spread of conditions favorable to pathogens
and mosquitoes.

How to reduce global warming-
• Reduce your own carbon footprint by following a few easy steps.
• Afforestation is one of the means to reduce Global warming.(Planting
more & more trees.)
• Make conserving energy a part of your daily routine and your decisions as
a consumer.
• When you shop for new appliances like refrigerators, washers, and dryers,
look for products with the government’s Energy Star label; they meet a
higher standard for energy efficiency than the minimum federal
requirements.
• When you buy a car, look for one with the highest gas mileage and lowest
emissions.
• You can also reduce your emissions by taking public transportation or
carpooling when possible.
• Cut down the current rate of CFCs and fossil fuel

4. Ozone layer depletion-
• The ozone layer is a thin layer in the atmosphere at an altitude of about
20-30 km that has a high concentration of ozone gas.
• It is made up of three atoms of oxygen and is represented as O3.
• This layer acts as UV filter – the earth’s natural sunscreen!
• UV rays are very harmful to living things.
• It can cause diseases like skin cancer and can also alter the climate
drastically.
• The ozone layer protects us from these harmful rays and is essential for
life on earth.
• The ozone layer is not uniform throughout the earth; it is thick at some
places and thin at others.
• If the this layer becomes too thin, it cannot stop the UV rays from
entering the earth and we say that a hole is formed in the ozone layer.

Causes of Ozone Layer Depletion
• The major cause of the thinning of the ozone layer is the use of chloro-flouro-
carbons or CFCs and Hydro- Chloro-flouro-carbons or HCFCs.
• They are compounds of chlorine, fluorine and carbon such as CF3Cl, CHCl2F etc.
• These are used as refrigerants in refrigerators, ACs and cooling plants. These
molecules can destroy O3 molecules and hence make the O3 layer thinner.
• Nitrogen oxides such as nitrous oxide are also very reactive to O3 and are also
responsible for holes in the ozone layer.
• These molecules are released by burning fossil fuels by cars and especially
airplanes which fly near the ozone layer.
• Since 1975, the hole has increased in size due to depletion in the ozone layer.
• Reductions of up to 70% have been found in some areas.
Prevention
• All is not lost though. The depletion of the O3 layer has almost stopped today and
there are signs that it can grow back.
• This is because countries around the world have agreed to stop the production
and use of CFCs and HCFCs.
• In January 1989, the Montreal protocol was signed to limit the use of CFCs and
HCFCs. 197 countries have ratified this protocol which has reduced CFC production
by 98% today.
• It remains the most successful environmental treaty to this date.
• Today there are better CFC free refrigerants available that do not pollute the
atmosphere. Almost all the air-conditioners and refrigerators you buy today do not
contain these harmful pollutants.

METEOROLOGICAL ASPECTS OF AIR POLLUTION
• Air movements influence the fate of air pollutants. So any study of air pollution should
include a study of the local weather patterns (meteorology).
• If the air is calm and pollutants cannot disperse, then the concentration of these
pollutants will build up. On the other hand, when strong, turbulent winds blow,
pollutants disperse quickly, resulting in lower pollutant concentrations.
• Meteorological data helps: When studying air quality, it is important to measure the
following factors as they can help us understand the chemical reactions that occur in
the atmosphere:
• wind speed and direction
• temperature
• humidity
• rainfall
• solar radiation.
• Wind speed and direction
• When high pollutant concentrations occur at a monitoring station, wind data records
can determine the general direction and area of the emissions.
• Identifying the sources means planning to reduce the impacts on air quality can take
place.
• An instrument called an anemometer measures wind speed. At our monitoring
stations, the type of anemometer we use is a sonic anemometer.

• Temperature
• Measuring temperature supports air quality assessment, air quality modelling
and forecasting activities.
• Temperature and sunlight (solar radiation) play an important role in the
chemical reactions that occur in the atmosphere to form photochemical smog
from other pollutants.
• Favourable conditions can lead to increased concentrations of smog.
• The most common way of measuring temperature is to use a material with a
resistance that changes with temperature, such as platinum wire. A sensor measures
this change and converts it into a temperature reading.
• Humidity
• Like temperature and solar radiation, water vapour plays an important role in
many thermal and photochemical reactions in the atmosphere. As water
molecules are small and highly polar, they can bind strongly to many
substances. If attached to particles suspended in the air they can significantly
increase the amount of light scattered by the particles (measuring visibility). If
the water molecules attach to corrosive gases, such as sulfur dioxide, the gas
will dissolve in the water and form an acid solution that can damage health and
property.
• Water vapour content of air is reported as a percentage of the saturation
vapour pressure of water at a given temperature.

AIR QUALITY STANDARDS
• Under the authority of the Air (Prevention and Control of Pollution) Act of
1981, India’s Central Pollution Control Board sets national ambient air
quality standards and is responsible for both testing air quality and assisting
governments in planning to meet such standards. State Pollution Control
Boards are permitted to set stricter standards than those in effect nationally.
• Interest in air quality management policies began in India during the 1970s.
After the 1972 Stockholm Conference on the Human Environment, it
became clear that the nation was in need of a uniform environmental law.
• As a result, the Air (Prevention and Control of Pollution) Act was passed by
Parliament in 1981. With the goal of providing for the prevention, control,
and abatement of air pollution, the first ambient air quality standards were
adopted in 1982 by the Central Pollution Control Board (CPCB) and revised in
1994 and again in 2009.
• Agencies responsible for air quality standard creation and monitoring
include CPCB and several State Pollution Control Boards (SPCBs). All of these
entities fall under the control of the Ministry of Environment and Forest
(MoEF). The CPCB, working together with the SPCBs, provides technical
advice to MoEF in order to fulfill the objectives outlined in the Air Act of
1981.

• TECHNICAL STANDARDS
• NATIONAL AMBIENT AIR QUALITY STANDARDS
Pollutant Averaging period Maximum (ambient)
concentration
Carbon monoxide 8 hours 9.0 ppm
Nitrogen dioxide 1 hour 0.12 ppm
1 year 0.03 ppm
Photochemical oxidants (as
ozone)
1 hour 0.10 ppm
4 hours 0.08 ppm
Sulfur dioxide 1 hour 0.20 ppm
1 day 0.08 ppm
1 year 0.02 ppm
Lead 1 year 0.50 µg/m
3
Particles as PM10 1 day 50 µg/m
3

Ways To Purify Home Air Naturally So Your Family Can
Breathe The Healthiest, Cleanest Air Possible
1. Increase Ventilation
• Ventilation in your home or office is not just opening a window. Outdoor air may still
contain pollution that you don’t want in your living spaces. Instead, consider installing
trickle vents to purify and cycle the air you breathe indoors.
2. Natural Air Conditioning
• - Try some of these tips to cool your home naturally.
• – Use ceiling fans
• – Install heat-blocking window treatments
• – Minimize use of heat-producing appliances
• – Grow plants for shade
3. Indoor Air Filters
• HEPA filters are an effective way to remove unwanted contaminants from indoor air.
4. Eliminate the Source
• Excessive moisture, dust build-up, smoking, and the use of chemical products like paint,
detergents, and synthetic fibers are among the most common causes of indoor air
pollution.
• Try to eliminate as many of these sources from your living spaces as possible and always
be on the lookout for all-natural alternatives to chemical-laden household items.

5. Beeswax Candles
• If you like to burn candles for natural light, avoid paraffin candles which release
petroleum byproducts into the air. Instead, opt for beeswax candles. Beeswax burns
clean and offers the added benefit of ionizing air to neutralize toxic compounds and
other contaminants.
• As an added bonus, beeswax candles burn slowly, so you have to replace them less
often.
6. Salt Lamps
• Himalayan pink salt is another natural ionic air purifier that pulls toxins from the
environment and neutralizes them. Add an Himalayan pink salt lamp to any room in
your home or office for both functionality and decoration.
7. Activated Charcoal
• Another great way to purify indoor air is with activated charcoal. Also known as active
carbon or simply carbon, activated charcoal is odorless and highly-absorptive.
8. Houseplants
• Plants are Mother Nature’s air purifiers. Try growing any of these houseplants to filter
toxins from the air in your home or office:
• Butterfly Palm , Lady Palm , Rubber Tree, Cornstalk Dracaena
• Peace Lily , Chrysanthemum , Golden Pothos , English Ivy, Chinese Evergreen .

Solutions for Air Pollution
• Use public mode of transportation: Encourage people to use more and more public
modes of transportation to reduce pollution. Also, try to make use of car pooling. If
you and your colleagues come from the same locality and have same timings you can
explore this option to save energy and money.
• 2. Conserve energy: Switch off fans and lights when you are going out. Large amount
of fossil fuels are burnt to produce electricity. You can save the environment from
degradation by reducing the amount of fossil fuels to be burned.
• 3. Understand the concept of Reduce, Reuse and Recycle: Do not throw away items
that are of no use to you. In-fact reuse them for some other purpose. For e.g. you can
use old jars to store cereals or pulses.
• 4. Emphasis on clean energy resources: Clean energy technologies
like solar, wind and geothermal are on high these days. Governments of various
countries have been providing grants to consumers who are interested in
installing solar panels for their home. This will go a long way to curb air pollution.
• 5. Use energy efficient devices: CFL lights consume less electricity as against their
counterparts. They live longer, consume less electricity, lower electricity bills and also
help you to reduce pollution by consuming less energy.
• Several attempts are being made world wide on a personal, industrial and
governmental levels to curb the intensity at which Air Pollution is rising and regain a
balance as far as the proportions of the foundation gases are concerned. This is a
direct attempt at slacking Global warming. We are seeing a series of innovations and
experiments aimed at alternate and unconventional options to reduce pollutants. Air
Pollution is one of the larger mirrors of man’s follies, and a challenge we need to
overcome to see a tomorrow.

Ways To Purify Air Artificially
Air purifier
• An air purifier or air cleaner is a device which removes contaminants from the air in a room.
These devices are commonly marketed as being beneficial to allergy sufferers and asthmatics,
and at reducing or eliminating second-hand tobacco smoke.
Purifying techniques
Several different processes of varying effectiveness can be used to purify air.
• Thermodynamic sterilization (TSS) - This technology uses heat sterilization via a ceramic core
with micro capillaries, which are heated to 200 °C (392 °] The air passes through the ceramic
core by the natural process of air convection, and is then cooled using heat tF). It is claimed
that 99.9% of microbiological particles - bacteria, viruses, dust mite allergens, mold and
fungus spores - are incinerated
• Ultraviolet germicidal irradiation - UVGI can be used to sterilize air that passes UV lamps via
forced air. Air purification UVGI systems can be freestanding units with shielded UV lamps that
use a fan to force air past the UV light.
• Filter - based purification traps airborne particles by size exclusion. Air is forced through a
filter and particles are physically captured by the filter.
• High-efficiency particulate arrestance (HEPA) filters remove at least 99.97% of 0.3-
micrometer particles and are usually more effective at removing larger particles
• Ionizer purifiers use charged electrical surfaces or needles to generate electrically charged air
or gas ions. These ions attach to airborne particles which are then electrostatically attracted
to a charged collector plate.
• Ozone generators are designed to produce ozone, and are sometimes sold as whole house air
cleaners. Unlike ionizers, ozone generators are intended to produce significant amounts of
ozone, a strong oxidant gas which can oxidize many other chemicals. The only safe use of
ozone generators is in unoccupied rooms,

Equipments used for Air Purification
1.Gravitational Settling Chamber
• They are generally used to remove large, abrasive particles (usually > 50 mm)
from gas streams. Since most of the troublesome particles have much smaller
size than 50 mm, there devices are usually used as per cleaners prior to
passing the gas stream through high efficiency collection device.
• Settling chambers, which rely on gravitational settling as a collection
mechanism, are the simplest and oldest mechanical collectors. Settling
chambers are generally built in the form of long, horizontal, rectangular
chambers with an inlet at one end and an exit at the side or top of the
opposite end.
• Flow within the chamber must be uniform and without any macroscopic
mixing. Hoppers are used to collect the settled-out material, though drag
scrapers and screw conveyers have also been employed.

• A multiple-tray settling chamber is an expansion chamber with a number of thin trays closely
spaced within the chamber, which causes the gas to flow horizontally between them.
• While the gas velocity is increased slightly in a multiple-tray chamber, when compared to a
simple expansion chamber, the collection efficiency generally improves because the particles
have a much shorter distance to fall before they are collected
The efficiency of settling chambers increases with residence time of the waste gas in the
chamber. Because of this, settling chambers are often operated at the lowest possible gas
velocities.
Advantages of Settling Chambers
• 1. Low capital cost;
• 2. Very low energy cost;
• 3. No moving parts, therefore, few maintenance requirements and low operating costs;
• 4. Excellent reliability;
• 5. Low pressure drop through device;
• 6. Device not subject to abrasion due to low gas velocity;
• 7. Provide incidental cooling of gas stream;
• 8. Temperature and pressure limitations are only dependent on the materials of construction;
and
• 9. Dry collection and disposal.
Disadvantages of Settling Chambers
• 1. Relatively low particulate matter collection efficiencies, particularly for particulate matter
less than 50 µm in size;
• 2. Unable to handle sticky or tacky materials;
• 3. Large physical size; and
• 4. Trays in multiple-tray settling chamber may warp during high-temperature operations

2. CYCLONE SCRUBBER
• Cyclonic scrubber uses the features of both the dry cyclone and the spray chamber to
remove pollutants from gas streams.
• The inlet gas enters the chamber tangentially, swirls through the chamber in a
corkscrew motion, and exits.
• At the same time, liquid is sprayed inside the chamber.
• As the gas swirls around the chamber, pollutants are removed when they impact on
liquid droplets, are thrown to the walls, and washed back down and out.
• Cyclonic scrubbers are generally low- to medium-energy devices, with pressure drops of
4 to 25 cm (1.5 to 10 in) of water, and are most often used to control large-sized
particulates.

3. BAGHOUSE FILTER
• A baghouse bag filter (BF) or fabric filter (FF) is an air pollution control device that removes
particulates out of air or gas released from commercial processes or combustion for
electricity generation.
• Power plants, steel mills, pharmaceutical producers, food manufacturers, chemical producers
and other industrial companies often use baghouses to control emission of air pollutants.
• Baghouses came into widespread use in the late 1970s after the invention of high-
temperature fabrics (for use in the filter media) capable of withstanding temperatures over
350 °F.
• Unlike electrostatic precipitators, where performance may vary significantly depending on
process and electrical conditions, functioning baghouses typically have a particulate collection
efficiency of 99% or better, even when particle size is very small.
• Most baghouses use long, cylindrical bags (or tubes) made of woven or felted fabric as a filter
medium.
• Dust-laden gas or air enters the baghouse through hoppers (large funnel-shaped containers
used for storing and dispensing particulate) and is directed into the baghouse compartment.
• The gas is drawn through the bags, either on the inside or the outside depending on cleaning
method, and a layer of dust accumulates on the filter media surface until air can no longer
move through it.
• When sufficient pressure drop (delta P) occurs, the cleaning process begins.
• Cleaning can take place while the baghouse is online (filtering) or is offline (in isolation).
When the compartment is clean, normal filtering resumes.
• Baghouses are very efficient particulate collectors because of the dust cake formed on the
surface of the bags.

NOISE POLLUTION
• The word noise is derived from a Latin word ‘Nausea’ which means sickness in which
one feels to vomit.
• Noise is the unpleasant and undesirable sound which leads to discomfort to human
beings.
• The intensity of sound is measured in decibels (Db).
• The faintest sound which can be heard by Human ear is 1 Db. Due to increasing noise
around the civilizations; noise pollution has become a matter of concern.
Causes of Noise Pollution
• 1. Industrialization: Most of the industries use big machines which are capable of
producing large amount of noise. Apart from that, various equipments like
compressors, generators, exhaust fans, grinding mills also participate in producing big
noise. Therefore, you must have seen workers in these factories and industries wearing
ear plugs to minimize the effect of noise.
• 2. Poor Urban Planning: In most of the developing countries, poor urban planning also
play a vital role. Congested houses, large families sharing small space, fight over
parking, frequent fights over basic amenities leads to noise pollution which may disrupt
the environment of society.
• 3. Social Events: Noise is at its peak in most of the social events. Whether it is marriage,
parties, pub, disc or place of worship, people normally flout rules set by the local
administration and create nuisance in the area. People play songs on full volume and
dance till midnight which makes the condition of people living nearby pretty worse. In
markets, you can see people selling clothes via making loud noise to attract the
attention of people.

• 4. Transportation: Large number of vehicles on roads, aeroplanes
flying over houses, underground trains produce heavy noise and
people get it difficult to get accustomed to that. The high noise
leads to a situation wherein a normal person lose the ability to hear
properly.
• 5. Construction Activities: Under construction activities like mining,
construction of bridges, dams, buildings, stations, roads, flyovers
take place in almost every part of the world. These construction
activities take place everyday as we need more buildings, bridges to
accommodate more people and to reduce traffic congestion. The
down point is that these construction equipments are too noisy.
• 6. Household Chores: We people are surrounded by gadgets and
use them extensively in our daily life. Gadgets like TV, mobile ,
mixer grinder, pressure cooker, vacuum cleaners , washing machine
and dryer, cooler, air conditioners are minor contributors to the
amount of noise that is produced but it affects the quality of life of
your neighborhood in a bad way.
• While this form of pollution may seem harmless, it in fact has far
reaching consequences. The adverse effects on the health of the
environment are quite severe. Not only is the local wildlife affected
by the pollution, humans also face a number of problems due to it.

Effect of Noise Pollution- There are many effects of noise pollution both
on human and animal health some of them are as follows:
• 1. Hearing Problems: Any unwanted sound that our ears have not been built
to filter can cause problems within the body. Our ears can take in a certain
range of sounds without getting damaged. Man made noises such as
jackhammers, horns, machinery, airplanes and even vehicles can be too loud
for our hearing range. Constant exposure to loud levels of noise can easily
result in the damage of our ear drums and loss of hearing. It also reduces our
sensitivity to sounds that our ears pick up unconsciously to regulate our body’s
rhythm.
• 2. Health Issues: Excessive noise pollution in working areas such as offices,
construction sites, bars and even in our homes can influence psychological
health. Studies show that the occurrence of aggressive behavior, disturbance
of sleep, constant stress, fatigue and hypertension can be linked to excessive
noise levels. These in turn can cause more severe and chronic health issues
later in life.
• 3. Sleeping Disorders: Loud noise can certainly hamper your sleeping pattern
and may lead to irritation and uncomfortable situations. Without a good night
sleep, it may lead to problems related to fatigue and your performance may go
down in office as well as at home. It is therefore recommended to take a
sound sleep to give your body proper rest.

• 4. Cardiovascular Issues: Blood pressure levels, cardio-vascular disease and stress
related heart problems are on the rise. Studies suggest that high intensity noise
causes high blood pressure and increases heart beat rate as it disrupts the normal
blood flow. Bringing them to a manageable level depends on our understanding
noise pollution and how we tackle it.
• 5. Trouble Communicating: High decibel noise can put trouble and may not allow
two people to communicate freely. This may lead to misunderstanding and you
may get difficult understanding the other person. Constant sharp noise can give
you severe headache and disturb your emotional balance.
• 6. Effect on Wildlife: Wildlife faces far more problems than humans because noise
pollution since they are more dependent on sound. Animals develop a better
sense of hearing than us since their survival depends on it. The ill effects of
excessive noise begin at home. Pets react more aggressively in households where
there is constant noise.
• They become disoriented more easily and face many behavioral problems. In
nature, animals may suffer from hearing loss, which makes them easy prey and
leads to dwindling populations. Others become inefficient at hunting, disturbing
the balance of the eco-system.
• Species that depend on mating calls to reproduce are often unable to hear these
calls due to excessive man made noise. As a result, they are unable to reproduce
and cause declining populations. Others require sound waves to echo-locate and
find their way when migrating. Disturbing their sound signals means they get lost
easily and do not migrate when they should.

Control measures for Noise Pollution
• SOURCE CONTROL: This includes source modification such as acoustic
treatment to machine surface, design changes, limiting operational
timings, etc
• TRANSMISSION PATH INTERVENTION: This includes containing the source
inside a sound insulating enclosure, constructing a noise barrier or
provision of sound absorbing materials along the path.
• RECEPTOR CONTROL: This includes protection of the receiver by altering
the work schedule or provision of personal protection devices such as ear
plugs for operating noisy machinery. The measure may include dissipation
and deflection methods.
• OILING: Proper oiling will reduce noise from the machine.
Preventive measures:
Prescribing noise limits for vehicular traffic
• Ban on honking (usage of horns) in certain areas
• Creation of silence zones near schools and hospitals
• Redesigning buildings to make them noise proof
• Reduction of traffic density in residential areas
• Giving preference to mass public transport system.

• Solutions of Noise Pollution
• Public awareness is essential for prevent and control the noise pollution. Not
only the government but we should also be aware of the harmful
consequences of noise pollution.
• Which cause to the certain deafness people should aware of that excessive
noise
• Such transport terminals, Industries, Airport, and railway terminals sight
should be far from living spaces.
• Avoid the maximum uses of sound processing instruments and make proper
regulations for the utilize of a loudspeaker and other devices.
• Construction of some soundproof machines in industrial and manufacturing
installation must be encouraged. Also necessary for residential building.
• Anti-pollution laws should make strict rules and regulation which enacted
and forced.
• Ban all type of fire crackers which is very harmful for pollution and replace
with the bulb horns.
• In the law of community must have a real and silence zone like Schools,
Colleges, and Hospitals.
• Make in the residential area the plantation (Trees) it absorbs the sound and
reduces the pollution and also healthier for breathing of body.

WATER POLLUTION
“Although water is nature’s most
wonderful, abundant and useful
compound, yet is also the most misused
one.”

SOURCES OF WATER
Without food, human can survive for a number of days, but water is such an
essential element that without it one cannot survive.
SOURCES OF WATER
|
.
| |
Surface Water Underground Water
I I I I
Rain River Lake Sea I I
water water water water Springs Well
(A) Surface water:
1. Rain water: is probably the purest form of natural water, since it is obtained as
a result of evaporation from the surface water. However, during the journey
downwards through the atmosphere, it dissolves a considerable amount of
industrial gases (like CO2, SO2, NO2, etc.) and suspended solid particles, both of
organic and inorganic origin.

2. River water: Rivers are fed by rain and spring waters. Water from these
sources flow over the surface of land, dissolves the soluble minerals of
the soil and finally falls in rivers. In general, the greater the contact that
water has with the soil, or the more soluble the minerals of the soils with
which it has come in contact the greater is the amount of dissolved
impurities in river water. River water thus contains dissolved minerals of
the soil such as chlorides, sulphates, bicarbonates of sodium, calcium,
magnesium and iron.
3. Lake water has a more constant chemical composition. It, usually,
contains much lesser amounts of dissolved minerals than even well
water, but quantity of organic matter present in it is quite high.
4. Sea water is the most impure form of natural water: Rivers join sea
and throw in the impurities carried by them. Moreover, continuous
evaporation of water from the surface of sea makes sea water
continuously richer in dissolved impurities. Sea water contains, on an
average, about 3.5% of dissolved salts, out of which about 2.6% is sodium
chloride.
Surface water, generally, contains suspended matter, which often
contains the disease-producing (or pathogenic) bacteria's. Hence, such
waters as such are not considered to be safe for human consumption.

(B) Underground waters: A part of the rain water, which reaches
the surface of the earth, percolates into the earth. As this water
journeys downwards, it comes in contact with a number of mineral
salts present in the soil and dissolves some of them. Water
continues its downwards journey, till it meet a hard rock, when it
retreads upwards and it may even come out in the form of ‘spring’.
Spring and well water (or underground water), in general, is clearer
in appearance, due to the filtering action of the soil, but contains
more of the dissolved salts. Thus, water from these sources
contains more hardness. Usually, underground water is of high
organic purity.

DRINKING WATER OR POTABLE WATER
Municipalities have to supply potable water, i.e., water which is safe to drink.
Drinking or potable water, fit for human consumption, should satisfy the following
essential requirements:
(1) It should be sparking clear and odourless.
(2) It should be pleasant in taste.
(3) It should be perfectly cool.
(4) Its turbidity should not exceed 10 ppm.
(5) It should be free from objectionable dissolved gases like hydrogen sulphide.
(6) It should be free from objectionable minerals such as lead, arsenic, chrominum
and manganese salts.
(7) Its alkalinity should not be high. Its pH should be about 8.0.
(8) It should be reasonably soft.
(9) It total dissolved solids should be less than 500 ppm.
(10) It should be free from disease-producing micro-organisms.
Purification of water for domestic use : Natural water from rivers, canals, etc., does
not confirm to all required specifications of drinking water. For removing various
types of impurities, the treatment processes are employed.

USES OF WATER – DOMESTIC, AGRICULTURE AND INDUSTRIAL
• Water used for domestic purposes
• Water is used for many different things at home.
• Water is used for cooking, cleaning, drinking and for sanitation.
• Providing sufficient drinking water and sanitation for people in
the developing countries in the world is one of the greatest
challenges at the present time.
• Two thirds of the 330 million living in 20 African countries lack
access to safe drinking water.
• The increasing number of human population all around the world
makes it difficult to supply the safe drinking water to everyone
especially in the developing countries.

Water used for agriculture
•Agriculture made use of the most water in the world.
•This is particularly in the case of Africa, Asia and South America.
•The use of water for irrigation per person varies greatly throughout
the world.
Water use for industries
•About 1/4 of water is used in the industry.
•Reference has been made in substantial use of water for cooling and
power generation.
Water also has a significant role to play as an input for most
manufacturing industries especially food processing, brewing and soft
drink manufacturing, chemicals and textiles.
•Much of the water used by the industries, is discharged back into
rivers and coastal water causing a significant amount of pollution.

CLASSIFICATION OF WATER POLLUTANTS
• Although some kinds of water pollution can occur through natural processes, it is mostly a
result of human activities.
• The eight classes of water pollutants are:
• Inorganic chemicals
• Organic chemicals
• Oxygen depleting wastes
• Infectious agents
• Plant nutrient pollutants
• Sediments
• Radioactive materials
• Thermal pollution
• 1.Inorganic chemical pollutants
Inorganic chemical pollutants are found in industrial discharge, chemicals in household
wastewater, and seepage from municipal dumps and landfills.
• The presence of these pollutants in water can render it undrinkable, as well as cause cancer
and birth defects.
• Sufficient concentrations of these chemicals in water can kill fish and other aquatic life, cause
lower crop yields due to plant damage, and corrode metals.
• These pollutants include mineral acids, toxic metals such as lead, cadmium, mercury, and
hexavalent chromium, mineral salts, etc.

2.Organic chemical pollutants
• These pollutants encompass a wide variety of
compounds including oil, pesticides, gasoline, and
organic solvents.
• They all degrade the quality of the water into which
they are discharged.
• Sources of these organic pollutants include industrial
discharge and runoff from farms and urban areas.
• Sometimes they enter aquatic ecosystems directly
when sprayed on lakes and ponds (e.g. for mosquito
control).
• These types of chemicals can cause cancer, damage
the central nervous system and cause birth defects in
humans,etc.

3.Oxygen depleting wastes
• Oxygen depleting wastes include animal manure in feedlot
and farm runoff, industrial discharge, plant debris, and urban
sewage.
• They are consumed by aerobic bacteria.
• Excessive growth of these organisms can deplete water of
dissolved oxygen whichleads to eutrophication and the
eventual death of oxygen consuming aquatic life.
• That is, excessive growth of these organisms occur
corrosion.
4.Infectious agents/Biological pollutants
• As a result of bacterial contamination in drinking water many
peoples become ill.
• Other examples of biological pollutants include viruses,
protozoa, and parasitic worms.
• These infectious agents enter the environment from human
and animal wastes, and they cause a variety of serious
diseases.

5.Plant nutrient pollutants
• They are found mainly in urban sewage, runoff from farms and gardens, and
household wastewater.
• These chemicals include nitrates (NO3-), phosphates (PO43-) and ammonium
(NH4+) salts commonly found in fertilizers and detergents.
• Excess of plant nutrients in the water can cause excessive algae growth in
lakes or ponds. This, in turn, results in the production of large amounts of
oxygen depleting wastes.
• The subsequent loss of dissolved oxygen causes eutrophication of the lakes
or ponds.
6.Sediments
• Erosion of soils is the main process contributing sediments, or silts, to water
bodies.
• Sediments can cloud the water of streams and rivers, reducing the amount of
available sunlight to aquatic plants.
• The concurrent reduction in photosynthesis can disrupt the local ecosystem.
Soil from croplands deposited in lakes and streams can carry bacteria,
pesticides, and other substances that are harmful to aquatic life.

7.Radioactive materials
• Such as iodine-131 and strontium-90, radioactive materials
are found in nuclear power plant effluents and fallout from
atmospheric nuclear testing.
• They can be introduced into the food chain through plants
and become incorporated in body tissues of humans and
animals. Their ionizing radiation can produce cancers,
especially in the thyroid and bone where they tend to
concentrate.
8.Thermal pollution
• Industrial discharges are one of the sources of thermal
pollution. The increased temperature of the water may locally
deplete dissolved oxygen and exceed the range of tolerance of
some aquatic species, thus disrupting the local ecosystem.
• Power generating plant commonly discharges water used for
cooling into a nearby river, lake, or ocean. Because the
discharged water can be significantly warmer than the
ambient environment, it represents a source of thermal
pollution.

DOMESTIC WASTE WATER SOURCES & CHARACTERISTICS
• Wastewater is the water which is disposed from homes, offices and industry. It comes from
toilets, sinks, showers, washing machines and industrial processes and was historically called sewa
• Wastewater produced due to human activities in households is called domestic wastewater i.e.
wastewater from the kitchen, shower, wash basin, toilet and laundry . It is defined as follows:
• Yellow water -- Human Urine
• Brown & Black water – Flushed from toilets
• Grey water– From kitchen , sink , washing etc
• The strength and composition of the domestic wastewater changes on hourly, daily and seasonal
basis, with the average strength dependent on per capita water usage, habits, diet, living
standard and life style. The main reason is variation in water usage in households.

Component Of special interest Environmental effect
Microorganisms Pathogenic bacteria, virus and worms
eggs
Risk when bathing and
eating shellfish
Biodegradable organic materials Oxygen depletion in rivers and lakes Fish death, odours
Other organic materials Detergents, pesticides, fat, oil
and grease, colouring, solvents,
phenols, cyanide
Toxic effect, aesthetic inconveniences,
bioaccumulation in the food chain
Nutrients Nitrogen, phosphorus, ammonium Eutrophication, oxygen depletion, toxic
effect
Metals Hg, Pb, Cd, Cr, Cu, Ni Toxic effect, bioaccumulation
Other inorganic materials Acids, for example hydrogen sulphide,
bases
Corrosion, toxic effect
Thermal effects Hot water Changing living conditions for flora and
fauna
Odour (and taste) Hydrogen sulphide Aesthetic inconveniences, toxic effect
Radioactivity Toxic effect, accumulation
Wastewater components can be divided into different main groups as shown in Table 1.
They can adversely affect the aquatic life if discharge them into environmental.

Physically, domestic wastewater is usually characterised by
a grey colour, musty odour and has a solids content of
about 0.1%.
• The solid material is a mixture of faeces, food particles,
toilet paper, grease, oil, soap, salts, metals, detergents,
sand and grit.
• The solids can be suspended (about 30%) as well as
dissolved (about 70%). Dissolved solids can be
precipitated by chemical and biological processes.
• From a physical point of view, the suspended solids can
lead to the development of sludge deposits
and anaerobicconditions when discharged into the
receiving Environment.

Chemically, wastewater is composed of organic (70%) and
inorganic (30%) compounds as well as various gases.
• Organic compounds consist primarily of carbohydrates (25
%), proteins (65 %) and fats (10 %), which reflects the diet
of the people.
• Inorganic components may consist of heavy
metals, nitrogen, phosphorus,
pH, sulphur, chlorides, alkalinity, toxic compounds, etc.
• However, since wastewater contains a higher portion of
dissolved solids than suspended, about 85 to 90% of the
total inorganic component is dissolved and about 55 to 60%
of the total organic component is dissolved.
• Gases commonly dissolved in wastewater are hydrogen
sulphide, methane, ammonia, oxygen, carbon dioxide
and nitrogen. The first three gases result from the
decomposition of organic matter present in the
wastewater.

Biologically, wastewater contains various microorganisms
but the ones that are of concern are those classified as
protista, plants, and animals. The category of protista
includes bacteria, fungi, protozoa, and algae.
• Plants include ferns, mosses, seed plants and
liverworts. Invertebrates and vertebrates are included
in the animal category.
• In terms of wastewater treatment, the most important
category are the protista, especially the bacteria, algae,
and protozoa
• Also, wastewater contains many pathogenic organisms
which generally originate from humans who are
infected with disease or who are carriers of a particular
disease.
• Typically, the concentration of faecal coliforms found in
raw wastewater is about several hundred thousand to
tens of million per 100 ml of sample.

INDUSTRIAL WASTE WATER- COMPOSITION & CHARACTERISTICS
• Industrial wastewater is one of the important pollution sources in the pollution of the
water environment.
• During the last century a huge amount of industrial wastewater was discharged into
rivers, lakes and coastal areas.
• This resulted in serious pollution problems in the water environment and caused
negative effects to the eco-system and human’s life.
• There are many types of industrial wastewater based on different industries and
contaminants; each sector produces its own particular combination of pollutants.
• Like the various characteristics of industrial wastewater, the treatment of industrial
wastewater must be designed specifically for the particular type of effluent produced.
• The amount of wastewater depends on the technical level of process in each industry
sector and will be gradually reduced with the improvement of industrial technologies.
• The increasing rates of industrial wastewater in developing countries are thought to be
much higher than those in developed countries.
• This fact predicts that industrial wastewater pollution, as a mean environment pollution
problem, will move from developed countries to developing countries in the early 21st
century.

CHARACTERISTICS OF
INDUSTRIAL WASTE
Physical
Characteristics
Chemical
Characteristics
Biological
Characteristics
Toxicity
Organic Matter Inorganic Matter
Measurement of
Organic Compound

WW
constituents
Suspended solid
Biodegradable
organics
pathogens
nutrients
Priority
pollutant
Refractory
organics
Heavy
metals
Dissolved
inorganics

PHYSICAL
CHARACTERISTICS
Total Solids
Odors
Temperature
Color
Turbidity

• The types of industrial waste water
• There are many types of industrial wastewater based on the different
industries and the contaminants; each sector produces its own particular
combination of pollutants
Sector pollutant
Iron and steel BOD, COD, oil, metals, acids, phenols, and
cyanide
Textiles and leather BOD, solids, sulfates and chromium
Pulp and paper BOD, COD, solids, Chlorinated organic
compounds
Petrochemicals and
refineries
BOD, COD, mineral oils, phenols, and
chromium
Chemicals COD, organic chemicals, heavy metals, SS,
and cyanide
Non-ferrous metals Fluorine and SS
Microelectronics COD and organic chemicals
Mining SS, metals, acids and salts

• Generally, industrial wastewater can be divided into two types
Inorganic industrial wastewater
• Inorganic industrial wastewater is produced mainly in the coal and
steel industry, in the
• nonmetallic minerals industry, and in commercial enterprises and
industries for the
• surface processing of metals (iron picking works and electroplating
plants).
• These wastewaters contain a large proportion of suspended matter,
which can be eliminated by sedimentation, often together with
chemical flocculation through the addition of iron or aluminum
salts, flocculation agents and some kinds of organic polymers.
• The purification of warm and dust-laden waste gases from blast
furnaces, converterscupola furnaces, refuse and sludge incineration
plants, and aluminum works results in wastewater containing
mineral and inorganic substances in dissolved and undissolved
form.

Organic industrial wastewater
• Organic industrial wastewater contains organic industrial waste flow
from those chemical industries and large-scale chemical works,
which mainly use organic substances for chemical reactions.
• The effluents contain organic substances having various origins and
properties. These can only be removed by special pretreatment of
the wastewater, followed by biological treatment.
• Most organic industrial wastewaters are produced by the following
industries and plants:
• ƒThe factories manufacturing pharmaceuticals, cosmetics, organic
dye-stuffs, glue and adhesives.
• soaps, synthetic detergents, pesticides and herbicides;
• ƒTanneries and leather factories;
• ƒTextile factories;
• ƒCellulose and paper manufacturing plants;
• ƒFactories of the oil refining industry;
• ƒBrewery and fermentation factories;

Biological Oxygen Demand
• This is a measure of the amount of molecular oxygen in milligrams required to
convert organic molecules contained in 1.0 liter of a water sample to CO2.
• Microorganisms such as bacteria are responsible for decomposing organic
waste.
• When organic matter such as dead plants, leaves, grass clippings, manure,
sewage, or even food waste is present in a water supply, the bacteria will begin
the process of breaking down this waste.
• When this happens, much of the available dissolved oxygen is consumed by
aerobic bacteria, robbing other aquatic organisms of the oxygen they need to
live.
• BOD level is a common metric for water pollution.
• The BOD level is determined by comparing the dissolved oxygen levels of a
water sample before and after 5 days of incubation in the dark.
• The difference between the two DO levels represents the amount of oxygen
required for the decomposition of any organic material in the sample and is a
good approximation of the BOD level.
Initial DO - Final DO = BOD

• Biochemical oxygen demand calculation procedure will tell about need of
fresh air to create the water useful for the marine lifestyle. If the BOD is
more, then we can say that effluent is more contaminated. Biochemical
oxygen demand calculation process takes five day to complete through
analysis.
• Apparatus required:
• BOD bottles -300 capacity
• BOD incubator
• Pipette
• Burette
• Measuring Jar
• 500 ml capacity iodine flask.
• Reagents required:
• Calcium chloride solution
• Phosphate buffer (pH-7.2)
• Ferric chloride solution
• Magnesium sulfate solution
• Alkali-iodide-azide reagent
• Manganese sulfate solution
• Concentrated sulfuric acid.

• Biochemical oxygen demand calculation procedure:
• Step 1 : Take 4 liters of aerated water.
• Step 2 : For 4 liters aerated water take 2 ml of sewage water.
Sewage water is for introducing the microorganisms. (For
3 liters, we have to take 1.5 ml of sewage water)
• Step 3 : Add 4 ml of Calcium chloride solution, 4 ml of
Phosphate buffer, 4 ml of Magnesium sulfate and 4 ml of
Ferric chloride as a nutrient for the survival of micro
organisms. (For 1 liter, we have to take 0.5 ml of all reagents
each)
• Step 4 : Mix thoroughly.
• Step 5 : Now fill the above solution in two bottles. One bottle
will be used for initial DO analysis. Another bottle will be used
for final DO after 5 days incubation.
• Step 6 : Now calculating the initial DO. Take 1ml of sample
and make up to 1 liter with dilution water. Mix and fill into 2
bottles until sample overflows and recap. Overflow is used for
removing any bubbles in it or any gas present in it.

• Step 7 : After taking into bottles add 2ml of manganese sulfate, 2ml of
sodium azide solution. Close the lid and mix it. Wait for 2 to 3 min to
settle down. Azide eliminates disturbance due tonitrate, which is the
most common disturbance in naturally handled effluents.
• Step 8 : Add 2ml of concentrated sulfuric acid. Close with lid and mix
until clear yellow solution forms.
• Step 9 : From the above solution take 200ml, and add 2ml of starch
and then titrate with 0.025M sodium thiosulfate upto colorless. Note
the titration value.
• Step 10 : We have to do the same procedure for the sample after 5
days present in the incubator.
• Biochemical Oxygen Demand Calculation ( BOD), is done by the
formula:
• BOD (mg/l) = [T1-T2] – [B1-B2] × 1000 / sample taken for 1 liter
• T1= Initial D.O. in sample.
• T2= After 5 days D.O. in sample.
• B1= Initial D.O in blank
• B2= After 5 days D.O in blank.

Chemical Oxygen Demand
• Chemical oxygen demand (COD) is a measure of the capacity
of water to consume oxygen during the decomposition of
organic matter and the oxidation of inorganic matter

• The COD is often measured using a strong oxidant
(e.g. potassium dichromate, potassium iodate,
potassium permanganate) under acidic
conditions.
• A known excess amount of the oxidant is added
to the sample.
• Once oxidation is complete, the concentration of
organics in the sample is calculated by measuring
the amount of oxidant remaining in the solution.
• This is usually done by titration, using an
indicator solution.
• COD is expressed in mg/L, which indicates the
mass of oxygen consumed per liter of solution.

• Procedure -
• Place several boiling stones in the reflux flask, followed by 50.0 mL of
sample or an aliquot diluted to 50.0 mL and 1 g of HgSO4
• Add 5.0 mL conc. H2SO4 ; swirl until the mercuric sulfate has
dissolved.
• Place reflux flask in an ice bath and slowly add, with swirling, 25.0 mL
of 0.025 N K2Cr2O7 .
• Now add 70 mL of sulfuric acid-silver sulfate solution to the cooled
reflux flask, again using slow addition with swirling motion.
• Caution: Care must be taken to assure that the contents of the flask
are well mixed. If not, superheating may result, and the mixture may
be blown out of the open end of the condenser.
• If volatile organics are present in the sample, use an allihn condenser
and add the sulfuric acid-silver sulfate solution through the
condenser, while cooling the flask, to reduce loss by volatilization.
• Apply heat to the flask and reflux for 2 hours. For some waste waters,
the 2-hour reflux period is not necessary.

• The time required to give the maximum oxidation for a
wastewater of constant or known composition may be
determined and a shorter period of refluxing may be permissible.
• Allow the flask to cool and wash down the condenser with about
25 mL of distilled water.
• . Dilute the acid solution to about 300 mL with distilled water and
allow the solution to cool to about room temperature.
• Add 8 to 10 drops of ferroin indicator to the solution and titrate
the excess dichromate with 0.25 N ferrous ammonium sulfate
solution to the end point.
• The color change will be sharp, changing from a blue-green to a
reddish hue.
• Simultaneously run a blank determination.
Calculations-
Vol. of FAS for blank = A
Vol. of FAS for Sample = B
Normality of FAS = N
Vol. of Sample = V
COD = A –B x N x8 x 1000
Vol. of sample

BASIC PROCESSES OF WATER TREATMENT
• The following is a step by step process of how
wastewater is treated:
• Wastewater Collection. This is the first step in waste
water treatment process. ...
• Odor Control. At the treatment plant, odor control is
very important. ...
• Screening. ...
• Primary Treatment. ...
• Secondary Treatment. ...
• Bio-solids handling. ...
• Tertiary treatment. ...
• Disinfection.

• Liquid Waste (Sewage/Wastewater) Treatment
Wastewater (liquid waste) from flushing the toilet, bathing, washing sinks
and general cleaning goes down the drain and into a pipe, which joins a
larger sewer pipe under the road. The larger pipe also joins a major pipe that
leads to the treatment center.
. STAGE ONE: SCREENING
Screening is the first stage of the wastewater treatment process. Screening
removes large objects like, diapers, nappies, sanitary items, cotton buds, face
wipes and even broken bottles, bottle tops, plastics and rags that may block or
damage equipment.
Special equipment is also used to remove grit that gets washed into the sewer.

• STAGE TWO: PRIMARY TREATMENT
This involves the separation of organic solid matter (or human waste) from the
wastewater. This is done by putting the wastewater into large settlement tanks for
the solids to sink to the bottom of the tank. The settled solids are called ‘sludge’.
At the bottom of these circular tanks, large scrappers continuously scrape the floor
of the tank and push the sludge towards the center where it is pumped away for
further treatment. The rest of the water is then moved to the Secondary
treatment.
• STAGE THREE: SECONDARY TREATMENT
The water, at this stage, is put into large rectangular tanks. These are called
aeration lanes. Air is pumped into the water to encourage bacteria to break down
the tiny bits of sludge that escaped the sludge scrapping process.
STAGE FOUR: FINAL TREATMENT
Next, the ‘almost’ treated wastewater is passed through a settlement tank. Here,
more sludge is formed at the bottom of the tank from the settling of the bacterial
action. Again, the sludge is scraped and collected for treatment. The water at this
stage is almost free from harmful substances and chemicals. The water is allowed
to flow over a wall where it is filtered through a bed of sand to remove any
additional particles.
The filtered water is then released into the river.

Industrial wastewater treatment
• Industrial wastewater treatment covers the mechanisms and processes used
to treat waste water that is produced as a by-product of industrial or
commercial activities. After treatment, the treated industrial
wastewater (or effluent) may be reused or released to a sanitary sewer or to a
surface water in the environment.
Treatment of industrial wastewater
• The different types of contamination of wastewater require a variety of
strategies to remove the contamination.
1.Solids removal
• Most solids can be removed using simple sedimentation techniques with the
solids recovered as slurry or sludge.
• Very fine solids and solids with densities close to the density of water pose
special problems.
• In such casefiltration or ultrafiltration may be required.
• Although, flocculation may be used, using alum salts or the addition
of polyelectrolytes.

2. Oils and grease removal
• Many oils can be recovered from open water surfaces by skimming
devices.
• skimming is also a cost-efficient method to remove most of the oil
before using membrane filters and chemical processes.
• Skimmers will prevent filters from blinding prematurely and keep
chemical costs down because there is less oil to process.
• The wastewaters from large-scale industries such as oil
refineries, petrochemical plants, chemical plants, and natural gas
processing plants commonly contain gross amounts of oil and
suspended solids. Those industries use a device known as an API
oil-water separator which is designed to separate the oil and
suspended solids from their wastewater effluents.
• The design is based on the specific gravity difference between the
oil and the wastewater because that difference is much smaller
than the specific gravity difference between the suspended solids
and water. The suspended solids settles to the bottom of the
separator as a sediment layer, the oil rises to top of the separator
and the cleansed wastewater is the middle layer between the oil
layer and the solids

3. Removal of biodegradable organics
• Biodegradable organic material of plant or animal
origin is usually possible to treat using extended
conventional wastewater treatment processes
such as activated sludge or trickling filter.
• Problems can arise if the wastewater is
excessively diluted with washing water or is
highly concentrated such as neat blood or milk.
• The presence of cleaning agents, disinfectants,
pesticides, or antibiotics can have detrimental
impacts on treatment processes.

Activated sludge process
• A generalized, schematic diagram of an activated sludge process.
• An aeration tank where air (or oxygen) is injected and thoroughly mixed
into the wastewater.
• A settling tank (usually referred to as a "clarifier" or "settler") to allow
the waste sludge to settle. Part of the waste sludge is recycled to
the aeration tank and the remaining waste sludge is removed for
further treatment and ultimate disposal.

Trickling filter process
The components of a complete trickling filter system are:
fundamental components:
A bed of filter medium upon which a layer of microbial slime is promoted and
developed.
An enclosure or a container which houses the bed of filter medium.
A system for distributing the flow of wastewater over the filter medium.
A system for removing and disposing of any sludge from the treated effluent.

• A trickling filter consists of a bed of rocks, gravel, slag, peat moss, or plastic media over
which wastewater flows downward and contacts a layer (or film) of microbial slime
covering the bed media.
• Aerobic conditions are maintained by forced air flowing through the bed or by natural
convection of air.
• The process involves adsorption of organic compounds in the wastewater by the
microbial slime layer, diffusion of air into the slime layer to provide the oxygen required
for the biochemical oxidation of the organic compounds.
• The end products include carbon dioxide gas, water and other products of the
oxidation.
• As the slime layer thickens, it becomes difficult for the air to penetrate the layer and an
inner anaerobic layer is formed.
• The treatment of sewage or other wastewater with trickling filters is among the oldest
and most well characterized treatment technologies.

4. Treatment of other organics
• Synthetic organic materials including solvents, paints, pharmaceuticals,
pesticides, coking products and so forth can be very difficult to treat.
• Treatment methods are often specific to the material being treated.
• Methods include
• Advanced oxidationProcessing, distillation, adsorption, vitrification,
incineration, chemical immobilisation or landfill disposal.
• Some materials such as some detergents may be capable of biological
degradation and in such cases, a modified form of wastewater treatment
can be used.
5.Treatment of toxic materials
• Toxic materials including many organic materials, metals (such as
zinc, silver, cadmium, thallium, etc.) acids, alkalis, non-metallic
elements (such as arsenic or selenium) are generally resistant to
biological processes unless very dilute.
• Metals can often be precipitated out by changing the pH or by
treatment with other chemicals.
• Many, however, are resistant to treatment or mitigation and may
require concentration followed by landfilling or recycling.
• Dissolved organics can be incinerated within
the wastewater by Advanced Oxidation Processes.

6. Treatment of acids and alkalis
• Acids and alkalis can usually be neutralised under controlled
conditions.
• Neutralisation frequently produces a precipitate that will
require treatment as a solid residue that may also be toxic.
• In some cases, gasses may be evolved requiring treatment for
the gas stream.
• Some other forms of treatment are usually required following
neutralisation.
• Waste streams rich in hardness ions as from de-ionisation
processes can readily lose the hardness ions in a buildup of
precipitated calcium and magnesium salts.
• This precipitation process can cause severe furring of pipes
and can, in extreme cases, cause the blockage of disposal
pipes.
• Treatment is by concentration of de-ionisation waste waters
and disposal to landfill or by careful pH management of the
released wastewater.

SOLID WASTE MANAGEMENT
• Solid waste management is a term that is used to refer to the process of
collecting and treating solid wastes. It also offers solutions for recycling items
that do not belong to garbage or trash.
• SOURCES AND TYPES OF SOLID WASTES
Source Typical waste generators Types of solid wastes
Residential Single and multifamily
dwellings
Food wastes, paper,
cardboard, plastics, textiles,
leather, yard wastes, wood,
glass, metals, ashes, special
wastes (e.g., bulky items,
consumer electronics, white
goods, batteries, oil, tires),
and household hazardous
wastes.).
Commercial Stores, hotels, restaurants,
markets, office buildings, etc.
Paper, cardboard, plastics,
wood, food wastes, glass,
metals, special wastes,
hazardous wastes.

Source Typical waste generators Types of solid wastes
Industrial Light and heavy manufacturing,
fabrication, construction sites,
power and chemical plants.
Housekeeping wastes,
packaging, food wastes,
construction and demolition
materials, hazardous wastes,
ashes, special wastes.
Institutional Schools, hospitals, prisons,
government centers.
Same as commercial.
Construction and demolition New construction sites, road
repair, renovation sites,
demolition of buildings
Wood, steel, concrete, dirt, etc.
Municipal services Street cleaning, landscaping,
parks, beaches, other
recreational areas, water and
wastewater treatment plants.
Street sweepings; landscape
and tree trimmings; general
wastes from parks, beaches,
and other recreational areas;
sludge.
Process (manufacturing, etc.) Heavy and light manufacturing,
refineries, chemical plants,
power plants, mineral extraction
and processing.
Industrial process wastes, scrap
materials, off-specification
products, slay, tailings.
Agriculture Crops, orchards, vineyards,
dairies, feedlots, farms.
Spoiled food wastes,
agricultural wastes, hazardous
wastes (e.g., pesticides).

Methods of Solid Waste Disposal and Management
Methods of solid waste disposal and management are as below:
• Open burning.
• Dumping into the sea.
• Sanitary Landfills.
• Incineration.
• Composting.
• Ploughing in fields.
• Hog feeding.
• Grinding and discharging into sewers.
• Salvaging
• Fermentation and biological digestion
1.Open burning of Solid Wastes
• Not an ideal method in the present day context
2.Dumping into Sea
• Possible only in coastal cities
• Refuse shall be taken in barges sufficiently far away from the coast (15-30 km) and
dumped there
• Very costly
• Not environment friendly

3. Sanitary Landfilling of Solid Wastes
• Simple, cheap, and effective
• A deep trench (3 to 5 m) is excavated
• Refuse is laid in layers
• Layers are compacted with some mechanical equipment and covered with earth,
leveled, and compacted
• With time, the fill would settle
• Microorganisms act on the organic matter and degrade them
• Decomposition is similar to that in composting
• Facultative bacteria hydrolyze complex organic matter into simpler water soluble
organics
• These diffuse through the soil where fungi and other bacteria convert them to carbon
dioxide and water under aerobic conditions
• Aerobic methanogenic bacteria utilize the methane generated and the rest diffuses into
the atmosphere
• Too much refuse shall not be buried – fire hazard
• Moisture content – not less than 60% for good biodegradation
• Refuse depth more than 3m – danger of combustion due to compression of bottom
layers – hence should be avoided
• Refuse depth is generally limited to 2m
• Temperature in the initial stages of decomposition – as high as 70 degree C – then
drops
• Reclaimed areas may be used for other uses

• 4. Incineration of Solid Waste
• A method suited for combustible refuse
• Refuse is burnt
• Suited in crowded cities where sites for land filling are not
available
• High construction and operation costs
• Sometimes used to reduce the volume of solid wastes for land
filling
• Primary chamber – designed to facilitate rapid desiccation of
moist refuse and complete combustion of refuse and volatile
gases
• A ledge or drying hearth is provided for this purpose
• Secondary chamber – between the primary chamber and the
stack – temperatures above 700 degree C
• All unburnt and semi burnt material are completely burnt here
• Modern combustors – combine solid waste combustion with
energy recovery

• Combustors for Solid Waste
• Storage pit – for storing and sorting incoming refuse
• Crane – for charging the combustion box
• Combustion chamber consisting of bottom grates on
which combustion occurs
• Grates on which refuse moves
• Heat recovery system of pipes in which water is turned
to steam
• Ash handling systems
• Air pollution control systems
• Grates – Provide turbulence so that the MSW can be
thoroughly burned, moves the refuse down, provides
under fire air to the refuse through openings in it (to
assist in combustion as well as to cool the grates)
• Operating temperature of combustors ~ 980 to 1090
degree C

5.Composting
• Similar to sanitary landfilling
• Yields a stable end product – good soil conditioner and
may be used as a base for fertilizers
• Popular in developing countries
• Decomposable organic matter is separated and
composted
• Methods
• Open window composting
• Mechanical composting

• Open window composting
• Refuse is placed in piles, about 1.5m high and 2.5m wide at about 60%
moisture content
• Heat build up in the refuse piles due to biological activity – temperature
rises to about 70 degree C
• Pile is turned up for cooling and aeration to avoid anaerobic conditions
• Moisture content is adjusted to about 60%
• Piled again – temperature rises to about 70 degree C
• The above operations are repeated
• After a few days (~ 7 to 10 weeks) temperature drops to atmospheric
temperature – indication of stabilization of compost
• Mechanical composting
• Process of stabilization is expedited by mechanical devices of turning the
compost
• Compost is stabilized in about 1 to 2 weeks
• To enrich compost – night soil, cow dung etc. are added to the refuse
• Usually done in compost pits
• Arrangements for draining of excess moisture are provided at the base of

6.Disposal by Ploughing into fields
• Not very commonly used
• Not environment friendly in general
7.Disposal by hog feeding
• Not common in India
• Refuse is ground well in grinders and then fed into sewers
• Disposal of garbage into sewers – BOD and TSS increases by 20-
30%
• Disposal of residual refuse – still a problem
8.Salvaging
• Materials like paper, metal, glass, rags, certain types of plastic
etc. can be salvaged, recycled, and reused
9.Fermentation or Biological Digestion
• Biodegradable Waste – convert to compost
• Recycle whatever is possible
• Hazardous wastes – dispose it by suitable methods
• Landfill or incinerate the rest

RECOVERY AND RECYCLING
• Why is recycling important?
• Recycling involves the sorting, collecting, and processing of
wastes such as paper, glass, plastic, and metals, which are then
refashioned or incorporated into new marketable products.
• When you throw stuff away, you might be very glad to get rid of
it: into the trash it goes, never to be seen again! Unfortunately,
that's not the end of the story
• They sometimes create toxic soil and water pollution that can kill
fish in our rivers and seas. But can also produce toxic air
pollution and burning almost anything (except plants that have
grown very recently) adds to the problem of global warming and
climate change.

Waste recovery offers many advantages.
• It conserves energy otherwise used to incinerate
the waste.
• Reduces the amount of landfill space needed for
the disposal of waste.
• Reduces possible environmental pollution
because of waste disposal.
• Generates jobs and small-scale enterprises;
reduces dependence on foreign imports of raw
materials.
• However, recycling sometimes requires more
energy and water consumption than waste
disposal.

1.Plastic Recycling
• Plastic recycling is the process of recovering different types of
plastic material in order to reprocess them into varied other
products, unlike their original form. An item made out of plastic
is recycled into a different product, which usually cannot be
recycled again.
Stages in Plastic Recycling
• Before any plastic waste is recycled, it needs to go through five
different stages so that it can be further used for making various
types of products.
• Sorting: It is necessary that every plastic item is separated
according to its make and type so that it can be processed
accordingly in the shredding machine.
• Washing: Once the sorting has been done, the plastic waste
needs to be washed properly to remove impurities such as
labels and adhesives. This enhances the quality of the finished
product.

• Shredding: After washing, the plastic waste is
loaded into different conveyer belts that run the
waste through the different shredders. These
shredders tear up the plastic into small pellets,
preparing them for recycling into other products.
• Identification and Classification of Plastic: After
shredding, a proper testing of the plastic pellets
is conducted in order to ascertain their quality
and class.
• Extruding: This involves melting the shredded
plastic so that it can be extruded into pellets,
which are then used for making different types
of plastic products

Metal
• Most of the metal we throw away at home comes
from food and drink cans and aerosols.
• Typically food cans are made from steel, which can
be melted down and turned into new food cans.
• Drinks cans are generally thinner and lighter and
made from aluminum, which can also be recycled
very easily.
• Mining aluminum is a very energy-intensive and
environmentally harmful process.
• That's why waste aluminum cans have a relatively
high value and why recycling them is such a good
thing to do.

Wood
• People have been reusing this traditional,
sustainable material for as long as human history.
• Waste wood is often turned into new wooden
products—such as recycled wooden flooring or
garden decking.
• Old wooden railroad sleepers (now widely replaced
by concrete) are sometimes used as building timbers
in homes and gardens.
• Waste wood can also be shredded and stuck
together with adhesives to make composite woods
such as laminates.
• It can also be composted or burned as a fuel.

Glass
• Glass is very easy to recycle; waste bottles and
jars can be melted down and used again and
again.
• You simply toss old glass into the furnace with
the ingredients you're using to make brand-new
glass.
• Bottle banks (large containers where waste glass
is collected) were the original examples of
community recycling in many countries.

Paper and cardboard
• In the early 1970s, photocopier manufacturers got scared
that we would stop using paper and turn into a "paperless
society." Not much chance of that! Forty years later, the
bad news is that we're producing more paper than ever
before.
• But the good news is that we're recycling more as well.
• Unlike some materials, paper can be recycled only so
many times.
• That's because it's made from plant fibers that become
shorter during paper-making.
• When they're too short, they no longer make decent
paper.
• In practice, this means some new paper always has to be
added during the papermaking process.

RECYCLING OF PAPER-
• Waste documents are usually covered in ink, which has to be
removed before paper can be recycled.
• Using bleach to de-ink papers can be an environmentally harmful
process and it produces toxic ink wastes that have to be disposed
of somehow.
• So, although recycling paper has many benefits, it comes with
environmental costs as well.
• One problem with recycling paper is that not all paper is the
same.
• White office printer paper is made of much higher quality raw
material than the paper towels you'll find in a factory washroom.
• The higher the quality of paper waste, the better the quality of
recycled products it can be used to make.

• So high-grade white paper collected from
offices can be used to make more high-grade
white recycled paper.
• But a mixture of old newspapers, office paper,
junk mail, and cardboard can generally be used
only to make lower-grade paper products such
as "newsprint" (the low-grade paper on which
newspapers are printed).
• Corrugated cardboard (which is held together
with glue) is harder to recycle than the thin
cardboard used to package groceries.

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