Primary School - Grades K-3
Elementary School - Grades 4-6
Middle School - Grades 7-9
Particulate Matter Emission from Air Fresheners: A Quantitative Study [E]
Does indoor or outdoor air have more particulate pollution? [E]
Which brand of furnace filter is most effective at straining particles from air? [P]
Geographic Distribution of Wind-Borne Particulates [E]
Effectiveness of Furnace Air Filters [P]
Which location in town has the most pollution? [P]
The Effects of Air Pollution on Mosquito Larvae [E]
If air pollution is measured in four different locations: a busy highway, a mountain home, a public school, and a park, then the greatest amount of pollution will be found at the busy highway, then the school, then the park, and then the least at the mountain home. [E]
Collect data on levels of particulate air pollution, and to analyze them by distance from various traffic and industrial sources in order to draw conclusions about their causes. [E]
See how different floor coverings (carpets) affect the amount of particulates in the air. [E]
Find how bad the air quality is for the cities: Orange, Anaheim Hills, Anaheim, Fullerton, Villa Park. Find the average for each city and compare it against the national average.Find if air quality changes from day to day. [E]
Impact of Air Quality on Adolescent Children's FEV1 Values [E]
Discover if houses that are situated along the airport flight path are more susceptible to air pollution than those houses outside the flight path. [E]
Find out if lung capacities of middle school children have been compromised by air pollution in their residential area (FEV1 values). [E]
How Does Cigarette Smoke Affect Crickets' chirping? [E]
Biomonitoring using Lichens as Bioindicators for Air Pollution [E]
Spray Patterns of Water and Oil Based Substances to Simulate Pesticide Movement in Still and Windy Environments [E]
Determine what material, when commonly burned, gives off the most black carbon particulates [E][P]
Car & Vehicle Pollution Science Fair Projects & Experiments
Ozone Science Fair Projects & Experiments
What is Air Pollution?
High School - Grades 10-12
Cleaning the world with sunscreen and pencils! [P][P]
Nasal Responses of Exposure to Ultrafine Iron Soot Particles in Mice [E]
Analysis of Magnesium Oxide Aerogel Air Filtration and Various Ways to Increase Its Efficiency [E]
Determine how carbon dioxide pollution affects the heart, specifically exercise heart rates, resting heart rates, and blood pressure. [E]
Examining the Effects of Organic Chemicals Present in Vehicle Exhaust on Wound Healing [E]
Dusty Problem Misty Solution: The Design and Testing of a PM-10 (Particulate Matter) Suppressant [E]
Effects of Atmospheric CO(2) on the Nitrogen Production Capabilities of Trichodesmium [E]
Effect of air Pollution on Chlorophyll Content and Lichen Morphology [E]
Compare the amounts of Carbon Dioxide in four common gas sources (human exhalation, ambient air, pure carbon dioxide, and automobile exhaust). [E]
The effect of wildfire ash on the environment [E]
Car & Vehicle Pollution Science Fair Projects & Experiments
Ozone Science Fair Projects & Experiments
What is Air Pollution?
Citation Guides, Style Manuals, Reference [R]
The Orchid Grower
Do you want create an amazing science fair project on Environmental Pollution? You are in the right place. Read the below given article to get a complete idea about:- 1. Meaning of Environmental Pollution 2. Air Pollution 3. Water Pollution 4. Noise Pollution 5. Legislation on Environmental Pollution.
- Science Fair Project on the Meaning of Environmental Pollution
- Science Fair Project on Air Pollution
- Science Fair Project on Water Pollution
- Science Fair Project on Noise Pollution
- Science Fair Project on the Legislation on Environmental Pollution
1. Science Fair Project on the Meaning of Environmental Pollution:
Environmental pollution may be described as the unfavourable alterations of our surroundings because of the acts and omissions of men. Man’s greed for quick economic gains has led to imbalance of this planet earth, thereby threatening the very survival of mankind. In our large and industrial towns, we are already experiencing the effects of air, water, soil and noise pollution which have already crossed the human tolerance.
Air pollution is mounted in cities due to higher growth of population and industrialisation. Water pollution has increased with the growth of population and industries. Disposal of industrial, commercial and household waste is becoming a problem. Noise has also become acute due to tremendous increase in motor vehicles.
Man has been subject to air pollution since his primordial ancestor lit the first fire. It was not, however, until people became crowded together in cities that pollution was more than a family problem associated with smoke from the hearth. With the coming of the use of coal for heating and the industrial revolution, the problem became intensified.
Today with the phenomenal growth of both the population and the use of power, pollution has reached such magnitude that it not only threatens the health and well-being of the population in a particular area, but also produces effects on a global scale.
Environment is a thing which is keeping Man alive, but he is steadily destroying it. Man chops down millions of trees every day that will never be planted again. For every 10 litres of petrol consumed, he releases 20 kgs of carbon dioxide.
He dumps tonnes of chemical and nuclear waste into the rivers and sea. The food, eaten by man is spread with lethal pesticides, which on long run can have serious side-effects like paralysis, kidney trouble, cancer etc. Artificial colours or preservatives used in food are also harmful.
2. Science Fair Project on Air Pollution:
Air pollution may be defined as the presence in the outdoor atmosphere of one or more contaminants or combination thereof in such quantities and of such duration as may be, or may tend to be injurious to human, plant or animal life, or property, or which unreasonably interfere with the comfortable enjoyment of life or property, or the conduct of business.
Atmosphere is a dynamic system, and absorbs various pollutants from natural as well as man-made sources, thus acting as a natural sink. Gases like CO, CO2, H2S, SO2 and NO2 as well as particulate matter such as sand and dust, are continuously released into the atmosphere through natural activities such as forest fires, decaying of vegetation, winds and sand or dust storms. Man-made pollutants e.g. CO, NO2, CO2, hydrocarbons, particulates are also released into atmosphere.
Now-a-days the problem of air-pollution has alarmingly increased due to population and other human activities. The pollutants are now-a-days enter the atmosphere at a faster rate than are absorbed by natural sink, thus accumulating in the air, and disturbing the equilibrium in the atmosphere, green-house effect on global warming is outcome of excessive pollution.
The United Nations Conference on the Human Environment held at Stockholm in 1972, in which India also was a participant, and in that conference firm decisions were taken by various countries to take appropriate step for the preservation of the natural resources of the earth which, among other things, include the preservation of the quality of air and control of air pollution.
In this background, the Air (Preservation and Control of Pollution) Act, 1981 was enacted by Government of India. The object of the Act is to provide for the prevention, control and abatment of air pollution.
As per this act, “air pollution” means the presence in the atmosphere of any air pollutant, and “air pollutant” means any solid, liquid or gaseous substance including noise present in the atmosphere in such concentration as may be or tend to be injurious to human beings or other living creatures or plants or property or environment.
Common Air Pollutants:
Following are the common air pollutants:
1. Carbon Monoxide (CO):
The atmospheric air contains 0.1 to 0.12 p.p.m. of CO.
Major part of CO in the atmosphere is due to:
(i) Automobile exhausts (60%),
(ii) Poorest fires and agricultural burning (17%), and
(iii) Industrial operations (10%).
In cities, due to pollution, level of CO in atmosphere reaches even upto 55 ppm. Although soil micro-organisms act as a major sink of CO from ambient atmosphere, still it exists significantly in the atmosphere. Large CO producing areas have now very less soil sink available around them.
2. Oxides of Nitrogen:
There are 8 possible oxides of nitrogen, but only N2O, NO and NO2 are common. These are 0.25 ppm, 0.1 to 2 ppm and 0.5 to 4 ppm respectively. NO and NO2 are significant from air pollution point of view. These are formed in the combustion process at high temperatures and are converted to UNO.
Level of these oxides is more in urban areas as compared to those of rural areas, and varies with the traffic intensity. Use of catalytic converters can minimize the level of these oxides. In industries also the level can be reduced by using a two stage combustion process.
3. Sulphur dioxide (SO2):
Combustion of any sulphur bearing material produces SO2, 33% SO2 emission is due to combustion of fuels, coal fired power houses, transport, refinery and metallurgical industries.
The concentration of man-made SO2 is in urban and industrial areas. SO2 reacts with water vapour to produce droplets of H2SO4. This may cause extensive damage to materials, water, vegetation, stone, steel, paint, fishes etc. Reduction of SO2 emission can be done by removing the sulphur content either before the fuel is burnt or during combustion or after combustion.
These are emitted by natural biological activities, automobile exhaust, burning of coal, oil, wood refuse etc.
Atmosphere contains several types of particles in varying sizes from 0.1 µ to 10 µ. These particles include dust, smoke, fog, ash etc. Dusts, mist, smoke, smog and fumes ire the result of these. Particulates may also result due to combustion of coal, fuel etc., and from automobile exhausts.
The particulates may enter the respiratory track and cause serious health hazards. The size and chemical characteristics of the particles are significant than their concentration. These are also capable of scattering light and reducing the visibility.
Sources of Air Pollution:
Man made activities are mainly responsible for the air pollution.
The main sources of air pollution are described hereunder:
(A) Fuel burning,
(B) Industrial processes, and
(C) Automobile exhaust.
Each of these sources is described here:
(A) Fuel Burning:
These operations are performed for heat and power generation. The fuel burnt may be coal, gases, oil, refuse, wood etc.
These are responsible for generating air pollution of the following types:
This is a product of incomplete combustion of coal, carbon monoxide, carbon dioxide etc.
It is finely divided powder and remains in atmosphere in floating condition. These are generated in large quantity in mining, quarrying, construction, cement industries etc.
Solid particles generated by condensation from gaseous state, and often accompanied by a chemical reaction such as oxidation, are known as fumes.
These are formless fluids.
This is a formation of heavy, cloudy, hazy, floating layer formed by the mixture of smoke, dust, fog, mist etc.
(B) Industrial Process:
As mentioned earlier industries like cement, chemical, textile, thermal power stations, steel plants, oil refineries, fertilizers etc. are main contributors to air pollution. Those are responsible for emitting harmful gases, fly ash, dust, soot.
With the proliferation of lead, mercury, oxides of nitrogen, ozone, cyanides, sulphur compounds etc. are responsible for health hazards and are increasing regularly. The workers working in mining, construction and cement industries have to inhale lot of dust and suffer from Asthema, Tuberculosis, Silicosia, Byssionosis etc.
(C) Automobile Exhaust:
Most of the vehicles and construction equipment are operated by diesel engines and their exhaust is responsible for major air-pollution. The construction equipment may be either stationary equipment without prime mover like air compressors, diesel generating sets, concrete mixers, dewatering pumps or may be with prime movers e.g., dumpers, transit mixers, compactors, shovels, excavators, graders, loaders, pavers etc.
Automobile exhausts have following main constituents:
Carbon monoxide, nitric oxides, unburnt hydrocarbons, partial oxidation products.
These include lead compounds, carbon and various other inorganic or organic materials.
Furthermore, additional hydrocarbons and fuel additives are contributed by the evaporation of gasoline from automobile tanks.
Emission from Diesel Engines:
Emission from diesel engine powered automobiles may be as follows:
Hydrocarbons – 200-500 p.p.m.
Carbon monoxide – 0.1 to 0.3%
Oxides of Nitrogen – 2000 to 3000 p.p.m.
Pollutants and their sources:
Pollutants and their sources of emission are:
Carbon Monoxide → Automobile exhaust
Sulphur dioxide → Oil burners
Nitric Oxide → Combustion
Nitrogen dioxide → Combustion
Ozone → Atmospheric photochemical reactions
Methane → Natural gas, decaying organic matter
Ethylene → Auto exhaust
Acetylene → Auto exhaust
Ammonia → Decaying organic matter
Hydrogen Sulphide → Decaying organic matter
Diesel Engine Combustion and Smoke:
Complete mixing of air and diesel in the combustion chamber is virtually impossible due to variation in the engine load and the quantity of the injected fuel. Some over-rich mixture is burned in the deficiency of the oxygen, which results production of CO, hydrocarbons and NO2.
These are the pollutants emitted from automobiles in the form of smoke. Some fuel molecules undergo thermal decomposition and dehydrogenation and produce soot formation, which also affects the density of the exhaust smoke.
The diesel engines emit less amount of CO, hydrocarbons and NO2 when well maintained.
The engine exhaust:
(a) Develops smog, reducing visibility and constituting a traffic hazard.
(b) Irritates the eyes, throat and the lungs.
(c) Is harmful for the food crops. The soot particles in the smoke spoil the building appearance.
(d) Has a disagreeable odour.
Production of hydrocarbons, CO and NO2 in combustion are explained hereunder:
These are the unburnt gasoline vapour coming out with the exhaust from the tail pipe. The main reason of these is the incomplete combustion of the fuel. They also occur due to fuel evaporation and crank case blow-by. These depend upon combustion chamber design, air fuel ratio, load and mode of operation of the engine.
(ii) Carbon Monoxide (CO):
Main reasons for carbon monoxide emission in the exhaust gases are the insufficient amount of air in the air fuel mixture and insufficient time available for complete combustion. Maximum amount of carbon monoxide is produced at the time of start, when supply of air is minimum.
(iii) Oxides of Nitrogen NO2:
They are the combination of nitric oxide (NO) and nitrogen dioxide (NO2). Increased combustion of fuel raises the temperature, and this increased temperature produces more nitrogen dioxide (NO2). The NO2 create pollution problem when released in the atmosphere.
The main factors which affect the formation of NO2 are: combustion temperature, presence of oxygen, spark advance, and air-fuel ratio. Increased spark advance produces high NO2 concentration in the exhaust, whereas the lean and rich mixtures produce low NO2 concentration.
Noxius Gas Pollution:
Combustion of fuel may be in diesel engines or burners etc., produces carbon monoxide, oxides of nitrogen, sulphur dioxide. Sulphur dioxide is most harmful amongst them. If its intensity is more, it may cause choking sensation, affect respiratory system, and damage the vegetation. Nitrogen dioxide is a colourless gas and is highly irritating to eyes and lungs.
Effects of Air Pollution:
Air pollution has many adverse effects. It damages the building structures, materials, vegetations, causes health hazards, and obstructs vision.
The effects of air pollution can be categorised as:
(a) Effects on human health,
(b) Effects on animals,
(c) Effects on plants,
(d) Effects on materials, and
(e) Effects on atmosphere.
(A) Effects on Human Health:
Air pollution seriously affects the respiratory system. Carbon monoxide when absorbed into the lungs and reduces the haemoglobin available to carry oxygen to the body. This may cause injury to vital organs. Sulphur dioxide also causes cough, shortens breath and can cause irritation to the eyes. It when converted to sulphuric acid damage the lungs.
It also helps in severe infections and allergic response. Even very low concentration of ozone can cause damage to the lungs. Hydrogen sulphide and other organic oxides can create odour problems. Hydrocarbons are believed to cause cancer in lung, whereas lead emitted by automobile exhausts is a cumulative poison and can cause brain damage.
Some of the chronic diseases due to exposure to polluted air are lung cancer, bronchitis, emphysema and asthma.
(B) Effects on Animals:
The effects of air pollution due to its inhaling on animals are similar to those on human. Air pollutants also enter the animal body through ingestion of contaminated plant materials. Among the metallic contaminants, arsenic, lead and molybdenum are important. Air contaminated with ozone, floride effects the forage crops, which when ate continuously by the animals affects the animals adversely.
(C) Effects on Plants:
As we know that leaf veins function as the transport system for water, minerals and food. The leaf tissues form cells in between them. Air pollution damages these leaf veins and tissues. The damage can be in the form of Necrosis (refers to dead areas on a leaf structure), Chlorosis (resulting in yellowing of the leaf), Abscission (dropping of leaves).
When the absorption of sulphur dioxide exceeds a particular level, the cells become inactive and are killed, resulting in tissue collapse and drying of plants adversely. Chlorine, ammonia, hydrogen sulphide, and ethylene also affect the vegetations adversely. Smog also causes injuries to the plants, and certain species are injured even with very small concentration of smog.
(D) Effects on Materials:
Air pollution also adversely affects building structures and materials. Smoke, dust and oxides of sulphur are most destructive pollutants. Sulphur dioxide changes with moisture and air to sulphuric acid which is corrosive.
Moisture, temperature, sunlight and air movement decide the rate of attack of pollutants. Aluminium, copper, iron and steel are corroded when exposed to contaminated air. Building structures are damaged/disfigured due to polluted air, sooty deposits, normal weathering.
(E) Effects on Atmosphere:
Increased combustion of fossil fuels and oil enhances the carbon dioxide concentration of the atmosphere. Carbon dioxide absorbs heat and the radiative cooling effect of the earth is thus decreased. CO2 is the single culprit responsible for half of global warming. This is known as “greenhouse effect” and is expected to raise the planet’s temperature between 1.5 and 4.5°C in about 60 years.
‘Greenhouse’ is a shield that keeps our planet warm enough to sustain life, but is now becoming a heat trap threatening to disrupt the global environment. A thin layer of certain gases, about 25 km like a greenhouse glass letting heat through but stopping enough radiation back into space to warm our world. But now “Greenhouse” layer is becoming denser, keeping in more heat.
Ozone layer is about 50-70 km above the earth’s surface. The ozone shell acts as a fence protecting from the incoming harmful ultraviolet rays. It screens out about 99% of ultraviolet radiations from reaching the earth’s surface.
Chloroflouro carbons (CFCs) which are mainly used in air conditioning, refrigeration and jet propellsion are mainly responsible for depleting the ozone. Excessive ultraviolet light are harmful for skin causing skin cancers and genetic composition of man as well as plants.
Preventing Air Pollution:
In order to prevent air pollution following steps must be taken:
1. Every one of us must feel responsibility and take initiative immediately to prevent air pollution.
2. We should start planting trees, as they purify the air, and thus keep the sky clean. Trees breathe carbon dioxide and release oxygen. Forests act as vast sinks for carbon dioxide and tend to reduce global warming.
3. Curtail vehicular emission by using them to minimum possible, using fuel efficient engines, and keeping vehicles in maintained condition. Conserve fuel, encourage mass transport, use cars in pools, monitor the fuel emission.
4. Polythene, plastic containers, polyurethane foams and P.V.C. are eco-non-friendly items, therefore their use should be avoided, disposal of these plastics is not an easy task, as burning produces soot, corrosive gases and4iighly offensive odour.
5. Avoid using aerosol products (airconditioners, refrigerators etc.) as these have chlorofluorocarbons (CFCs) which depletes the ozone umbrella. ,
6. Maximise use of solar energy use of solar heaters, solar energy, electric plants be encouraged.
7. Air pollution monitoring should be carried out regularly.
8. While preparing a project, environment management plan should be prepared for formation, implementation and monitoring of environmental protection measures during and after commissioning of projects.
9. Emission levels of pollutants from chimneys should conform to the pollution control standards prescribed by the central or state pollution control boards, for which necessary arrangements must be made.
Generally used air cleaning devices are:
(a) Electrostatic precipitators,
(b) Cyclone separators,
(c) Wet collectors,
(d) Gravity settlers,
(e) Bag filters,
(f) Cyclone filters,
(g) Wet scrubbers, and
(h) Absorbers or Adsorbers.
For indoor pollution, use proper ventilation so that used air or vitiated air gets removed by fresh air.
Control of Air Pollution:
A. Control of Pollutants:
For the purpose of air pollution control, the pollution can be divided into following categories:
1. Particulate control in chimneys.
2. Particulate control in atmosphere.
3. Dust control.
1. Particulate control in chimneys:
Plants used in construction, cement industries, thermal power plants etc., emit particulates through chimneys. These emit dusts of coal, stone, cement, lime sand etc. and combustion gases. The persons engaged on these plants and in nearby areas are badly affected by this type of pollution.
These also adversely affect the nearby residential areas, and cultivated farm etc. Dust collectors are required to be installed with such plants to remove suspended particles from the chimney emission. The Dust Collectors are of several types, and their suitability is required to be decided depending upon the characteristics of the particulate.
2. Particulate control in atmosphere:
In construction, cement, and mining industries thermal plant areas, coal, stone aggregates, ore, sand etc. are stored at site or plant areas. These should be maintained in such a condition so as to prevent dust from becoming wind borne while in storage or being handled, loaded or transported.
Following steps may help in this respect:
(i) Wetting of material to prevent dust becoming wind borne.
(ii) Location of stock piles in an area, protected from prevailing winds.
(iii) Installation of wind-breaks i.e. trees, walls etc. to protect stockpiles from direct exposure to the prevailing winds.
(iv) Storage of materials in bins, silos or any other type of enclosures.
(v) Plant and plant areas should be cleaned regularly of accumulated dust, dirt etc.
3. Dust Control:
Dusts emitted due to haulage, working of heavy earth moving equipment etc., are needed to be controlled by adopting following measures:
(i) Maintaining haul roads, moving the vehicles at reasonable speed, sprinkling water on unpaved haul roads.
(ii) Heavy earth moving equipment’s should be provided with cabins so as to protect the operators.
B. Site Selection:
For installing an industry, it is necessary to select the site which will have minimum adverse effects on people, animals, agriculture etc.
C. Control of Motor Vehicles Emission:
In order to control emission from motor vehicles proper maintenance including engine tuning, use of catalytic reactors etc. are necessary.
D. Use of Latest Technology:
Equipment’s with latest technology, fuel efficient engines, plants with dust collectors etc. should be used so as to have better control over air pollution.
3. Science Fair Project on Water Pollution:
India is a country blessed with both perennial rivers and rivers with seasonal flow of water besides water sources in the form of lakes, ponds, sea inlets as well as a vast sea-shore which provide a source of livelihood for many.
Over the years, the growth of industrial activity has tended to pollute the water courses making the water unsuitable for both drinking as well as for irrigation, besides rendering water unfit for the survival of fish and other aquatic living beings. Due to increasing tendency of urbanisation; it is essential to ensure that the domestic and industrial effluents are not allowed to be discharged into the water courses without adequate treatment.
The water (Prevention and Control of Pollution) Act 1974 enacted to provide for the prevention and control of water pollution and the maintaining or restoring of wholesomeness of water.
As per this act, “water pollution” means such contamination of water or such alteration of the physical, chemical or biological properties of water or such discharge of any sewage or trade effluent or of any other liquid, gaseous or solid substance into water as may, or is likely to, create a nuisance or render such water harmful or injurious to public health or safety, or to domestic, commercial, industrial, agricultural or other legitimate uses, or to the life and health of animals or plants or of aquatic organisms.
In short, “Water Pollution” can be defined as the adverse change in composition or condition of water so that it becomes less suitable for the purposes for which it would be suitable in its natural state.
These changes may be physical, chemical, biological or radioactive. Thus water pollution means addition of anything to water which changes the natural quality of water so that people residing in downstream does not receive the natural water of the stream.
Sources of Water Pollution:
There are large numbers of sources which pollute the water, but following are the main sources of water pollution:
Raw or ill-treated municipal or domestic sewage is generally poured into the rivers or canals. This may cause the water borne diseases like typhoid, cholera, dysentery; infections etc., sewage may seep into the empty water pipe due to which fungi, colonial bacteria etc., may flock in.
2. Industrial effluents:
Most industries pour their toxic and obnoxious effluents into rivers. These industrial effluents contain both organic and inorganic hazardous materials and non-biodegradable materials. These when discharged into rivers, are injurious to public health and destroys many fishes and water birds in downstream. Mineral oil floats from the petroleum and natural gas drilling units into the rivers and oceans. Mine water also takes acidic water, ores etc.
3. Agriculture and Fertilizers:
Fertilizers, insecticides, pesticides, herbicides used in agricultural practices leach into the rivers and canals. Fungicides employed in treating seeds have mercury compounds. Phosphates, nitrates and ammonium groups enter the water flow through the inorganic fertilizers, which are very harmful to human beings.
4. Refuse and spoil heaps:
Underground water pollution occurs by the substances leached from refuse, spoil heaps and fertilizers spread over the land. This type of pollution is more serious due to difficulty in treatment of the polluted water.
5. Pollution in Ocean:
Discharge of sewage and industrial effluents, discharge of sewage and rubbish from ships, transportation of oil and exploration of the sea bed also pollute the sea. Tons of plastic trash is dumped overboard which is adversely affecting the life of sea animals. Apart from ship wrecks the offshore oil production is a major cause of spillage. These kill large number of sea birds or fishes etc.
Nature and Effects of Water Pollution:
Water may have following contaminants:
These can cause damage to metals or concrete structures pumps etc. due to their corrosive property. These also adversely affect the fishes and other aquatic animals.
Like acids, these also adversely affect the fishes and other aquatic animals.
These are found from the discharge of effluents from dyeing and printing industries, textile industries, paper and ink manufacturing industries etc., these impart colours and create aesthetic problems.
(iv) Fats, soaps and waxes:
These produce unpleasant odours.
(v) Gaseous pollutants:
Presence of excess amount of free chlorine in rivers as;
(a) It is a powerful irritant,
(b) It causes a disease of the lungs of man,
(c) It destroys the aquatic life, and
(d) It is corrosive.
Presence of hydrogen sulphide causes odour nuisance, respiratory problems, irritation, and is lethal to fishes. Presence of ozone is highly toxic to fish. Carbon dioxide and carbon monoxide are also harmful to the fishes.
These are harmful for men as well as fishes.
(vii) Toxic Metals:
Lead, arsenic, copper, cadmium, mercury, nickel etc. are toxic to living organisms. These kill the aquatic plants and animals. These prevent the use of water for drinking purposes.
Fuel oils create the aesthetic problems, re-aeration of water is affected. The oil coats the gills offish and thus affects respiration of fish. This spoils the beaches making bathing impossible in such places.
The object of sewage treatment is to remove Biochemical Oxygen Demand (BOD), phosphorus, nitrogen, solids and bacteria. It is necessary for converting a raw and harmful sewage into an-acceptable effluent.
The treatment processes are divided into following three groups:
1. Primary Treatment:
This has a mechanical process and includes screening, grinding, flocculation and sedimentation. Screening removes larger suspended and floating materials. Grinders have cutting teeth used to chop the solid material into smaller pieces. Flocculation is an agitation process which makes the smaller suspended particles to form floes so that they can settle out rapidly.
In sedimentation, the suspended solids are removed by gravitational settling. The primary treatment reduces 60 percent of the total suspended solids, 35 percent BOD, 20 percent Chemical Oxygen Demand (COD) and 10 percent of nitrogen and phosphorous.
2. Secondary Treatment:
This is a biological process when the wastes are fed onto trickling filter beds; they trickle or percolate over the stones (or other filling materials of the beds). In activated sludge process, biologically active growths are continuously circulated through organic waste in the presence of oxygen.
Aeration activates the sludge particles. Secondary treatment reduces 90 percent BOD, 80 percent COD, 50 percent of total nitrogen, 30 percent of total phosphorous and 90 percent of suspended matter.
3. Tertiary Treatment:
These are the advanced biological, chemical and physical processes. This method is used for purification of waste water, and also in the recycling of waste water. This method is more efficient for removal of pollutant.
This treatment is carried out in following steps:
(a) Chemical coagulation and filtration:
In this, chemical coagulants like alum and ferrous sulphate react with suspended matter to form floes which settle out rapidly. Thereafter filtration is done.
This process is used for removing odours. Activated carbon (porous carbon) is used as adsorbing material.
(c) Chemical oxidation:
In order to get pure water, waste water is oxidised by using ozone or hydrogen peroxide.
This process removes the dissolved substances. For this purpose ion exchange, reverse osmosis and electro dialysis techniques may be employed.
(e) Oxidation ponds:
In this process, organic matters are decomposed by bacteria and are consumed by algae.
Treatment of Water:
Water whether from underground or from surface source found in nature are polluted. This water cannot be supplied directly for drinking purposes due to aesthetic, physiological, transmission of water borne diseases etc. Natural water may also have decaying leaves, vegetations or animals, minerals in soluble or suspended state.
For all these reasons water requires treatment. It must be free from germs of diseases, unpleasant tastes and odours. Degree and methods of treatment depend on the nature of source, quality of water and purpose for which it is required.
Various treatment methods and the impurities removed by them are given hereunder:
It is not necessary to adopt all the above mentioned processes. Selection of treatment process depends on the quality of water available at the source and that required for the purpose. Ground water is free from suspended solids, but often causes problems due to hardness.
Prevention of Water Pollution:
Water pollution can be prevented by adopting following actions:
(i) Each drop of water is precious, save it.
(ii) Use kitchen wastes to make organic fertilizers, as these are more beneficial compared to the inorganic ones.
(iii) Recycle the effluents. Heavy metals could be recovered from the industrial effluents.
(iv) Keep away spraying pesticides. Use of neem leaves is encouraged.
(v) Use biomass for generating electricity.
(vi) Waste water treatment processes, should be adopted.
(vii) Garbage should be dumped in selected areas and use garbage compactors. Solid wastes should be sent for recycling.
(viii) Avoid using polybags, encourage use of cloth or canvas bags.
4. Science Fair Project on Noise Pollution:
Noise may be defined as unwanted sound at a wrong time and at wrong place. Generally prolonged and loud sound is considered as noise. Meaningful sound is generally meant for inviting attention or expecting a consequent response, such as the cry of a baby.
Sounds when soft, rhythmic and for short duration are acceptable, but they are unacceptable when loud, random or prolonged. Excessive noise can result in loss of hearing, increase in accidents decrease productivity.
It is therefore necessary to reduce noise pollution particularly in urban and industrial areas.
Level of sound from certain sources is indicated hereunder:
Effects of Sound at different levels are:
135 dB – Painful
110 dB – Discomfortable
88 dB – Hearing impairment on prolonged exposure
65 dB – Intrusive
(a) Physiological Effects:
Immediate permanent hearing impairment may be caused at high levels of about 150 dB. Sound levels in the range of 120-150dB, effects on respiratory system, dizziness, loss of physical control, and other changes due to stress, nausea, and vomiting may be caused. Even sounds of the level of 70 dB may have measurable physiological effects.
(b) Psychological and other effects:
Deterioration in concentration and even mental disorientation has been noticed at high noise levels, though temporarily. Loud continuous noise reduces the working efficiency, interferes with communication, and increases the frequency of errors in working which may even cause accidents.
Noise Pollution in Construction Industry:
High level noises are created in the plants due to collision or friction of metal against metal, aggregate against aggregate, and metal against aggregate, movement of compressed air into the atmosphere, and the combustion of fuel in the burner. Areas of high level noises are: crushers, burners, blowers, exhaust fans, pug mills.
Operators in most plants are therefore housed in cabin, where exposure level to noise is reduced. If an employee is required to work near plant area without cabin, it should be for shorter durations, as prolonged exposure in excessive noise is irritating, produce mental fatigue and reduce the efficiency of persons around the plants, especially asphalt plants where noise level is too high.
Approaches for Noise Control:
Following are the main approaches which are used for noise control:
1. Modify the present practices and procedure so as to minimise the noise level e.g., use of welding instead of riveting,
2. Shielding the source of noise generation e.g., use of sound absorbing motor mountings, better installations, better design, use of enclosures for motors, use of vibration damping etc.
Regular maintenance also helps in reducing the noise level. Sound absorption, sound insulation and vibration control also help in transmitting the noise from the source. The paths of noise transmission may be through structure of machinery; surface and panels attached to the source; cables, conduits, wires, pipes, ducts, belts etc.
3. Shielding the noise receiver e.g., using carefully earplug, earmuff, helmets, control cabins etc. Wherever noise level cannot be reduced, the persons working in high noise level are need be protected.
Methods of Noise Control:
Depending upon the circumstances noise can be reduced upto some extent by using baffles, sound proof materials, by doing proper maintenance and lubrication, mounting the noise and vibration source on flexible supports, providing conveyors to avoid fall of material on metals from height.
Industrial noise control methods include following steps:
(i) Replacing noise producing machinery with quiet alternatives,
(ii) Interrupting the path with insulating material,
(iii) Follow the noise control approaches as described above, and
(iv) Protecting the workers by providing earmuffs.
Community noise is mainly due to air traffic, highway traffic and construction activities. To control these noises flight paths are diverted from populated areas to other areas. The highway traffic causes noise due to noise of exhaust, engine, tire, gears and transmission, and aerodynamic (wind) noise. Modern cars are being made to produce less noise, but heavy vehicles still produce too much noise. The solution to this problem is only to have highways away from populated areas, designing nonstop operations, smooth traffic flow.
Now-a-days noise is also produced by sources responsible for luxaries like TVs, stereos, orchestra, loudspeakers, fireworks, generators, coolers, air-conditioners, mixers and grinders, washing machines etc. These noises can only be controlled or contained by public awareness.
Trees are supposed to be the best for noise control. More and more trees should be planted along the roads, rail tracks and around the aerodromes. These should be planted in plenty in colonies, hospitals, school campuses etc. to protect the people from noise pollution from outside.
5. Science Fair Project on the Legislation on Environmental Pollution:
Government of India has adopted various legislations related to various environmental aspects, from time to time, some of the main legislations are:
1. Water (Prevention and Control of Pollution) Act passed in 1974.
2. Air (Prevention and Control of Pollution) Act passed in 1981.
3. Establishment of Pollution Control Boards through Water Act.
4. Environment (Protection) Act a comprehensive legislation passed in 1986 is meant for total protection of the environment.
5. Forest (Conservation) Act 1980.
6. The Wild life (Protection) Act, 1972.
Government of India has also issued following policy statements with an idea of ‘integrated natural resource management’ and ‘ecological units of planning’ for land use:
1. National Conservation Strategy.
2. Policy Statement on Environment and Development.
3. Policy Statement for Abatement of Pollution.
4. National Forest Policy 1988.
Because of handful of polluters, the entire humanity is suffering and people are being deprived of their legitimate right of clean environment. Environmental problems like polluted water, dirty air, too much noise, are the major cause of millions of deaths and illnesses across the globe.
Today, it is unfortunate that man has forgotten that he is a product of his environment and all his social, moral, spiritual, health and economic wellbeing depends on his harmony with nature only. Despite greater awareness and debate about the disastrous consequences of environmental destruction, people all over the world continue to plunder the global environment.
Therefore, realising the need for strict enforcement of environment and human rights laws to protect and preserve the basic rights of the people; and also to save the present and succeeding generations from the scourage of pollution and to protect their dignity, the above mentioned Acts have been enacted by the Government.
The objective of these Acts is the improvement of environment and the prevention of hazards to human beings, other living creatures, plants and property.
In order to achieve the desired objective and to have better enforcement of laws, the knowledge base on environmental law has to be broadened and all the environmental protection laws should be brought under one umbrella and laws for deterrent punishment need to be enacted for criminals destroying the environment for their personal gains. Further, the laws need simplification which will encourage compliance.