Air pollution by Industry:

Air pollution by Industry:

Air pollution is the presence of high concentration of contaminations, dust, smokes etc., in the general body of air man breaths. Prime sources of air pollution are the industrial activities or processes releasing large quantity of pollutants in the atmosphere. These pollutants are mainly: (a) Smoke comes out from various industries like, power plants, chemical plants, other manufacturing facilities, motor vehicles, etc.; (b) Burning of wood, coal in furnaces and incinerators; (c) gaseous pollutants from Oil refining industries; (d) dust generated and thrown to general atmosphere by various industries such as cement plants, ore / stone crushing units, mining industries due to rock drilling & movements of mining machineries & blasting etc.; (e) Waste deposition for landfills which generate methane; (f) Toxic / germ / noxious gasses and fumes generated from military activities and explosives blasting in mines.

Air pollution control devices / equipments for industries:

The commonly used equipments / process for control of dust in various industries are (a) Mechanical dust collectors in the form of dust cyclones; (b) Electrostatic precipitators – both dry and wet system; (c) particulate scrubbers; (d) Water sprayer at dust generation points; (e) proper ventilation system and (f) various monitoring devices to know the concentration of dust in general body of air.

The common equipments / process used for control of toxic / flue gases are the (a) process of desulphurisation; (b) process of denitrification; (c) Gas conditioning etc. and (d) various monitoring devices to know the efficacy of the systems used.

Mechanism of Adverse Impact of Smoke Pollutant:

Mechanism of Adverse Impact of Smoke Pollutant:

The main sources of smoke pollutants in urban areas are Petrol / Diesel driven motor vehicles, Fuel combustion in stationary sources including residential, commercial and industrial heating / cooling system and coal-burning power plants etc.

Petrol / Diesel driven motor vehicles produce high levels of Carbon Dioxide (CO2) / Carbon Monoxide (CO), major source of Hydrocarbon (HC) and Nitrogen oxides (NOx). Fuel combustion in stationary sources is the dominant source of Carbon Dioxide (CO2) and Sulfur Dioxide (SO2).

Carbon Dioxide (CO2) – This is one of the major gas pollutants in the atmosphere. Major sources of CO2 are due to burning of fossil fuels and deforestation. Industrially developed countries like USA, Russia etc., account for more than 65% of CO2 emission. Less developed countries with 80% of world’s population responsible for about 35% of CO2 emission. Due to high growth reported from less developed countries in last decade, it is estimated that, the Carbon dioxide emissions may rise from these areas and by 2020 their contribution may become 50%. It has also been seen that, Carbon dioxide emissions are rising by 4% annually.

As ocean water contain about 60 times more CO2 than atmosphere; CO2 released by the industry leads to disturbance of equilibrium of concentration of CO2 in the system. In such a scenario, the oceans would absorb more and more CO2 and atmosphere would also remain excess of CO2. As water warms, ocean’s ability to absorb CO2 is reduced. CO2 is a good transmitter of sunlight, but partially restricts infrared radiation going back from the earth into space. This produces the so-called “Greenhouse Effect” that prevents a drastic cooling of the Earth during the night. This so-called “Greenhouse Effect” is responsible for GLOBAL WARMING. Currently Carbon Dioxide is responsible for major portion of the global warming trend.

Nitrogen oxides (NOx) - They come mainly from nitrogen based fertilizers, deforestation, and biomass burning. Nitrogen oxides contribute mostly as atmospheric contaminants. These gases are responsible in the formation of both acid precipitation and photochemical smog and causes nitrogen loading. These gases have a role in reducing stratospheric ozone.

Sulfur Dioxide (SO2) - Sulfur dioxide is produced by combustion of sulfur-containing fuels, such as coal and fuel oils. SO2 also produced in the process of producing Sulfuric Acid and in metallurgical process involving ores that contain sulfur. Sulfur oxides can injure man, plants and materials. As emissions of sulfur dioxide and nitric oxide from stationary sources are transported long distances by winds, they form secondary pollutants such as nitrogen dioxide, nitric acid vapor, and droplets containing solutions of sulfuric acid, sulfate, and nitrate salts. These chemicals descend to the earth's surface in wet form as rain or snow and in dry form as a gases fog, dew, or solid particles. This is known as acid deposition or acid rain.

Choloroflurocarbons (CFCs) - Chlorofluorocarbons, also known as Freons, are greenhouse gases that contribute to global warming. CFCs are responsible for lowering the average concentration of ozone in the stratosphere.

Smog – Smog is the result from the irradiation by sunlight of hydrocarbons caused primarily by unburned gasoline emitted by automobiles and other combustion sources. Smog is created by burning coal and heavy oil that contain mostly sulfur impurities.

Soil erosion and its prevention:

Soil erosion and its prevention:

Soil erosion by water, wind and tillage affects both agriculture and the natural environment. Soil loss, and its associated impacts, is one of the most important (yet probably the least well-known) of today's environmental problems. It is mostly due to poor land use practices, which include deforestation, overgrazing, unmanaged construction activity and road or trail building.

Soil is a complex mixture of living and non-living materials. It provides anchorage and sustenance to plants. Natural agents like water and wind, constantly tend to remove the top soil and cause erosion. Rain falling upon the unprotected top soil, washes it down into the streams. Due to the absence of plant covering, eroded soil cannot hold water. Water rushes into the rivers and overflows as flood. Dust storm also causes soil erosion. The particles of top soil are picked up in such quantities that they form clouds of dust. Human beings also cause soil erosion. The growing human habitation and expansion of urban areas lead to removal of vegetation. Once vegetation is removed, the naked soil gets exposed to wind and water. Improper tillage is another cause of soil erosion. Farmers often loosen the top soil for removing weeds and preparing seed beds. They also leave agricultural fields lying fallow for long time. These practices expose the top soil to the wind and cause erosion.

Soil erosion is always a result of mankind's unwise actions, such as overgrazing or unsuitable cultivation practices. These leave the land unprotected and vulnerable. Accelerated soil erosion by water or wind may affect both agricultural areas and the natural environment, and is one of the most widespread of today's environmental problems. Soil erosion is just one form of soil degradation. Other kinds of soil degradation include salinisation, nutrient loss, and compaction.

Prevention of soil erosion: Plants provide protective cover on the land and prevent soil erosion for the reasons: (a) plants slow down water as it flows over the land (runoff) and this allows much of the rain to soak into the ground; (b) plant roots hold the soil in position and prevent it from being washed away; (c) plants break the impact of a raindrop before it hits the soil, thus reducing its ability to erode; (d) plants in wetlands and on the banks of rivers are of particular importance as they slow down the flow of the water and their roots bind the soil, thus preventing erosion.

Preventing soil erosion requires technical changes to adopt. Aspects of technical changes include: (i) use of contour ploughing and wind breaks; (ii) leaving unploughed grass strips between ploughed land; (iii) making sure that there are always plants growing on the soil, and that the soil is rich in humus (decaying plant and animal remains). This organic matter is the "glue" that binds the soil particles together and plays an important part in preventing erosion; (iv) avoiding overgrazing and the over-use of crop lands; (v) allowing indigenous plants to grow along the river banks instead of ploughing and planting crops right up to the water's edge; (vi) encouraging biological diversity by planting several different types of plants together; (vii) conservation of wetlands (see Enviro Facts "Wetlands" and "River Catchments").

We can check soil erosion by adopting the following additional practices:

1. Intensive cropping and use of proper drainage canals.

2. Terracing on the sloping fields. This retards the speed of the flowing water.

3. Planting trees and sowing grasses.

4. Extensive aforestation practices to be carried out.

Interrelationship of population, environment and development:

Interrelationship of population, environment and development:

Population and Environment: Rapid increase in population disturbs the biotic environment. The rate, at which world population is increasing, is alarming. Human beings are forced to encroach upon forests, mountains, sea and rivers, for space and food. More habitable and cultivable land is required, as also more space is needed for grazing the cattle. Wild animals are being killed indiscriminately for food and money. Trees are being cut to satisfy the needs of fuel and timber. This has caused an ecological crisis. If it is not checked, it is bound to bring disaster. Explosion of population has also caused overcrowding. It has caused physical discomfort, which creates mental tension. Living with mental tension is bound to cause social and health disorders.

Environment and Sustainable Development: In earlier days, human beings were leading a harmonious life with nature. In the age of science and technology, they are capable of using more natural resources to create an environment of their own. As such, the natural environment is shaped, guided and directed by socio-economic considerations. This practice has led to degradation of natural environment. Old villages, hills, beaches, etc., have been converted into cities and big towns. In order to increase communication for trade purposes, a network of roads and transport has been established. Tourism has been given importance and big hotels have been constructed. Agricultural lands have been used in constructing big hotels, industries, etc. Big dams have been constructed in order to generate more electricity for the industries. Water bodies have shrunken.

To maintain a balance between environment and development, it is necessary to strive for sustainable development to meet the needs of present generation without foreclosing the options for future generation. To achieve this, one has to consider different aspects of development. Conservation, sustainability and biological diversity are interrelated. If human beings have to survive, they have to live in harmony with nature. More plants have to be planted. Green grassy patches have to be interspersed between concrete buildings. We will have to adopt such technologies which are environment friendly sound, and based on maximizing recycling and efficient use of resources – practices which are inherent in India’s traditions.

Environment Engineering and its importance:

Environment Engineering and its importance:

Since the beginning of the Nineteenth century, the explosive growth, expansion and needs of the world’s population accompanied by new technological advances have modified our Mother Earth’s landscape. Man has exploited the natural resources in such a way that it leads to over-exploitation and losing the balance in natural eco-system.

Environmental Degradation is the process by which the environment is progressively contaminated, over-exploited and destroyed. They can be mainly grouped into (a) eco-system imbalance, (b) forest deterioration, (c) freshwater degradation (d) soil degradation (e) air pollution and (f) Global warming.

Environmental studies are the systematic study of human interaction with their environment. It is a broad field of study that includes the natural environment, social environments, organizational environments, and the relationships between them. Current environmental problems have evolved into a complex set of interdisciplinary issues involving ecological, political, economic, social, as well as physical and biological considerations.

Environmental engineering is the application of science and engineering principles to improve the environment (air, water, and/or land resources), to provide healthy water, air, and land for human habitation and for other organisms and to set right the polluted sites, as far as possible. In short, Environmental Engineering involves water and air pollution control, recycling, waste disposal, and public health issues as well as knowledge of environmental engineering law. It also includes studies on the environmental impact of proposed industrial projects and finds effective ways to mitigate those harmful effects.

Important Environmental Issues Of Today Due To Human Activity:

Sl.No.	Issues	Effects
1	Change of climate	a. Global warming, b. Rise in Sea level causing submerge of low lying landmass, c. Reduction of Ice cover
2	Energy	a. Energy conservation & Efficient use of energy b. Extensive use of Renewable Energy
3	Land Degradation	a. Less agricultural yield due to loss in nutrient b. Loss in agricultural land c. Salinisation of farm land d. Compaction of land

Conservation and protection of environment

Conservation and protection of environment

By now, all of us have realized how important it is to protect the environment for our own survival. The term ‘conservation’ of environment relates to activities which can provide individual or commercial benefits, but at the same time, prevent excessive use leading to environmental damage. Conservation may be distinguished from preservation, which is considered to be “maintaining of nature as it is, or might have been before the intervention of either human beings or natural forces.” We know that natural resources are getting depleted and environmental problems are increasing. It is, therefore, necessary to conserve and protect our environment. Following practices help in protecting our environment.

1. Rotation of crops.

2. Judicious use of fertilisers, intensive cropping ,proper drainage and irrigation.

3. Treatment of sewage, so that it does not pollute the rivers and other water bodies.

4. Composting organic solid waste for use as manure.

5. Planting trees in place of those removed for various purposes.

6. National parks and conservation forests should be established by the government.

7. Harvesting of rain water.

Some action points to protect or improve the environment:

(i) Dispose the waste after separating them into biodegradable and non-biodegradable waste material.

(ii) Start a compost heap or use a compost bin. This can be used to recycle waste food and other biodegradable materials.

(iii) Avoid unnecessary or wasteful packaging of products.

(iv) Reuse carry bags.

(v) Plant trees. They will help to absorb excess carbon dioxide.

(vi) Observe World Environment Day on 5th June.

(vii) Never put any left over chemicals, used oils down the drain, toilet or dump them on the ground or in water or burn them in the garden. If you do so, it will cause pollution.

(viii) Don’t burn any waste, especially plastics, for the smoke may contain polluting gases.

(ix) Use unleaded petrol and alternate sources of energy, and keep the engine properly tuned and serviced and the tyres inflated to the right pressure, so that vehicle runs efficiently.

(x) Avoid fast starts and sudden braking of automobiles.

(xi) Walk or cycle where it is safe to do so – walking is free; cycling can help to keep you fit.

(xii) Use public transport wherever you can, or form a car pool for everyday travel.

(xiii) Send your waste oil, old batteries and used tyres to a garage for recycling or safe disposal; all these can cause serious pollution.

Global warming and greenhouse gasses:

Global warming and greenhouse gasses:

The earth is surrounded by a cover of gasses as atmosphere. This atmosphere allows most of the light to pass through, which reaches the surface of earth. This light from sun is absorbed by the earth surface and converts into heat energy. This heat energy is re-emitted by the surface of the earth during night. Due excessive presence of some gasses in the atmosphere, this escape of heat from earth surface is prevented, resulting in heating of earth called ‘global warming’. The gasses which are responsible for causing global warming are called ‘greenhouse gasses’.

The harmful effects of presence of greenhouse gasses in atmosphere are global warming, climate change, ozone depletion, sea level rise, adverse effects on biodiversity etc. One way or another these adverse impacts are all directly or indirectly related to the presence of greenhouse gases in the atmosphere. A number of human activities, processes and consumptions produce waste gasses or greenhouse gasses that are harmful to the environment. They include:

(a) Fuel combustion
(b) Energy industries
(c) Manufacturing industries and construction
(d) Vehicle Transport and automobiles
(e) Fugitive emissions from fuels
(f) Burning of solid fuels
(g) Use of oil and natural gas
(h) Mineral products
(i) Chemical industry
(j) Metal production
(k) Production of halocarbons and sulfur hexafluoride
(l) Consumption of halocarbons and sulfur hexafluoride
(m) Solvent and other product use
(n) Enteric fermentation
(o) Manure management
(p) Rice cultivation
(q) Agricultural soils
(r) Prescribed burning of savannas
(s) Field burning of agricultural residues
(t) Solid waste disposal on land
(u) Wastewater handling
(v) Waste incineration

Much of these harmful gases are produced either naturally or by various human activities; which we should reduce. Brief description and effects of six important greenhouse gases are given below:

Carbon dioxide (CO2) - A naturally occurring gas produced by living organisms and fermentation. It is a normal component of the breath we exhale; it is hazardous in concentrated volumes. Large quantity of carbon dioxide is produced by the combustion of carbonaceous fuels. Carbon dioxide emissions from fuel burning, responsible for about 87 percent of global warming, have increased by about 27 percent since the industrial revolution.

Nitrogen oxides (NOx) – Nitrogen oxides are naturally occurring from microbial action in soil. NOx is also produced by fuel burning. Scientists say its production is increased by the use of nitrogen based fertilizers in agriculture, as well as by the use of catalytic converters in automobiles.

Methane (CH4) – Methane is a naturally occurring, in-flammable gas. Methane is produced by geological coal formations and by the decomposition of organic matters. Leading man-related sources of methane are landfills; livestock digestive processes and waste, especially ruminants (cud-chewing animals); and wetland rice cultivation.

Hydroflurocarbon gasses (HFCs) - Chlorofluorocarbons (CFC), the coolant, cleaning, and propellant gases were blacklisted internationally due to its ozone-eating characteristics. HFCs do contribute to global warming. Global warming potential of HFCs is 4,000 to 10,000 times that of CO2.

Perfluorocarbons (PFC), or perflurocompounds - Man-made replacement gases for CFCs but result also as a by-product of aluminium smelting. PFCs also used as a purging agent for semi-conductor manufacture and small amounts are produced during uranium enrichment processes. Global warming potential of Perfluorocarbons (PFC), or perflurocompounds is 6,000 to 10,000 that of CO2.

Sulfur hexafluoride (SF6) - Very low atmospheric concentration makes it an ideal test gas for gas concentration monitors. Principle uses: insulating material for high-voltage equipment like circuit breakers at utilities. Also used in water leak detection for cable cooling systems. SF6 is a man-made gas.

Fundamentals of our environment and environmental problems:

Fundamentals of our environment and environmental problems:

We know that, a living organism cannot live by itself. Organisms interact among themselves. Hence, all organisms, such as plants, animals and human beings, as well as the physical surroundings with whom we interact, form a part of our environment. All these constituents of the environment are dependent upon each other. Thus, they maintain a balance in nature. As we are the only organisms try to modify the environment to fulfill our needs; it is our responsibility to take necessary steps to control the environmental imbalances.

The environmental imbalance gives rise to various environmental problems. Some of the environmental problems are pollution, soil erosion leading to floods, salt deserts and sea recedes, desertification, landslides, change of river directions, extinction of species, and vulnerable ecosystem in place of more complex and stable ecosystems, depletion of natural resources, waste accumulation, deforestation, thinning of ozone layer and global warming. The environmental problems are visualized in terms of pollution, growth in population, development, industrialization, unplanned urbanization etc. Environmental pollution is defined as the undesirable change in physical, chemical and biological characteristics of our air, land and water. As a result of over-population, rapid industrializations, and other human activities like agriculture and deforestation etc., earth became loaded with diverse pollutants that were released as by-products. Pollutants are generally grouped under two classes:

(a) Biodegradable pollutants - Biodegradable pollutants are broken down by the activity of micro-organisms and enter into the biogeochemical cycles. Examples of such pollutants are domestic waste products, urine and faucal matter, sewage, agricultural residue, paper, wood and cloth etc.

(b) Non- Biodegradable pollutants - Non-biodegradable pollutants are stronger chemical bondage, do not break down into simpler and harmless products. These include various insecticides and other pesticides, mercury, lead, arsenic, aluminum, plastics, radioactive waste etc.

Pollution can be classified according to the components of environment that are polluted.These are: (A) Air pollution (B) Water pollution (C) Soil pollution (land degradation).

(A) Air Pollution - Air is mainly a mixture of various gases such as oxygen, carbon dioxide, nitrogen. These are present in a particular ratio. Whenever there is any imbalance in the ratio of these gases, air pollution is caused. The sources of air pollution can be grouped under (i) Natural; such as, forest fires, ash from smoking volcanoes, dust storm and decay of organic matters. (ii) Man-made due to population explosion, deforestation, urbanization and industrializations. Certain activities of human beings release several pollutants in air, such as carbon monoxide (CO), sulfur dioxide (SO2), hydrocarbons (HC), oxides of nitrogen (NOx), lead, arsenic, asbestos, radioactive matter, and dust. The major threat comes from burning of fossil fuels, such as coal and petroleum products. Thermal power plants, automobiles and industries are major sources of air pollution as well. Due to progress in atomic energy sector, there has been an increase in radioactivity in the atmosphere. Mining activity adds to air pollution in the form of particulate matter. Progress in agriculture due to use of fertilizers and pesticides has also contributed towards air pollution. Indiscriminate cutting of trees and clearing of forests has led to increase in the amount of carbon dioxide in atmosphere. Global warming is a consequence of green house effect caused by increased level of carbon dioxide (CO2). Ozone (O3) depletion has resulted in UV radiation striking our earth.

Harmful Effects of air pollution are: (a) it affects respiratory system of living organisms and causes bronchitis, asthma, lung cancer, pneumonia etc. Carbon monoxide (CO) emitted from motor vehicles and cigarette smoke affects the central nervous system. (b) Due to depletion of ozone layer, UV radiation reaches the earth. UV radiation causes skin cancer, damage to eyes and immune system. (c) Acid rain is also a result of air pollution. This is caused by presence of oxides of nitrogen and sulfur in the air. These oxides dissolve in rain water to form nitric acid and sulfuric acid respectively. Various monuments, buildings, and statues are damaged due to corrosion by acid present in the rain. The soil also becomes acidic. The cumulative effect is the gradual degradation of soil and a decline in forest and agricultural productivity. (d) The green house gases, such as carbon dioxide (CO2) and methane (CH4), trap the heat radiated from earth. This leads to an increase in earth’s temperature. (e) Some toxic metals and pesticides also cause air pollution.

(B)Water Pollution - Water is one of the prime necessities of life. With increasing number of people depend on this resource; water has become a scarce commodity. Pollution makes even the limited available water unfit for use. Water is said to be polluted when there is any physical, biological or chemical change in water quality that adversely affects living organisms or makes water unsuitable for use. Sources of water pollution are mainly factories, power plants, coal mines and oil wells situated either close to water source or away from sources. They discharge pollutants directly or indirectly into the water sources like river, lakes, water streams etc. The harmful effects of water pollution are: (a) human beings become victims of various water borne diseases, such as typhoid, cholera, dysentery, hepatitis, jaundice, etc. (b) The presence of acids/alkalies in water destroys the microorganisms, thereby hindering the self-purification process in the rivers or water bodies. Agriculture is affected badly due to polluted water. Marine eco-systems are affected adversely. (c) The sewage waste promotes growth of phytoplankton in water bodies; causing reduction of dissolved oxygen. (d) Poisonous industrial wastes present in water bodies affect the fish population and deprives us of one of our sources of food. It also kills other animals living in fresh water. (e) The quality of underground water is also affected due to toxicity and pollutant content of surface water.

(C) Soil pollution (Land degradation) - Land pollution is due to (i) deforestation and (ii) dumping of solid wastes. Deforestation increases soil erosion; thus valuable agricultural land is lost. Solid wastes from household and industries also pollute land and enhance land degradation. Solid wastes include things from household waste and of industrial wastes. They include ash, glass, peelings of fruit and vegetables, paper, clothes, plastics, rubber, leather, brick, sand, metal, waste from cattle shed, night soil and cow dung. Chemicals discharged into air, such as compounds of sulfur and lead, eventually come to soil and pollute it. The heaps of solid waste destroy the natural beauty and surroundings become dirty. Pigs, dogs, rats, flies, mosquitoes visit the dumped waste and foul smell comes from the waste. The waste may block the flow of water in the drain, which then becomes the breeding place for mosquitoes. Mosquitoes are carriers of parasites of malaria and dengue. Consumption of polluted water causes many diseases, such as cholera, diarrhea and dysentery.