Water pollution by industries and its effects:

Water pollution by industries and its effects:

A change in the chemical, physical, biological, and radiological quality of water that is injurious to its uses. The term “water pollution” generally refers to human-induced changes to water quality. Thus, the discharge of toxic chemicals from industries or the release of human or livestock waste into a nearby water body is considered pollution.

The contamination of ground water of water bodies like rivers, lakes, wetlands, estuaries, and oceans can threaten the health of humans and aquatic life. Sources of water pollution may be divided into two categories. (i) Point-source pollution, in which contaminants are discharged from a discrete location. Sewage outfalls and oil spills are examples of point-source pollution. (ii) Non-point-source or diffuse pollution, referring to all of the other discharges that deliver contaminants to water bodies. Acid rain and unconfined runoff from agricultural or urban areas falls under this category.

The principal contaminants of water include toxic chemicals, nutrients, biodegradable organics, and bacterial & viral pathogens. Water pollution can affect human health when pollutants enter the body either via skin exposure or through the direct consumption of contaminated drinking water and contaminated food. Prime pollutants, including DDT and polychlorinated biphenyls (PCBs), persist in the natural environment and bioaccumulation occurs in the tissues of aquatic organisms. These prolonged and persistent organic pollutants are transferred up the food chain and they can reach levels of concern in fish species that are eaten by humans. Moreover, bacteria and viral pathogens can pose a public health risk for those who drink contaminated water or eat raw shellfish from polluted water bodies.

Contaminants have a significant impact on aquatic ecosystems. Enrichment of water bodies with nutrients (principally nitrogen and phosphorus) can result in the growth of algae and other aquatic plants that shade or clog streams. If wastewater containing biodegradable organic matter is discharged into a stream with inadequate dissolved oxygen, the water downstream of the point of discharge will become anaerobic and will be turbid and dark. Settleable solids will be deposited on the streambed, and anaerobic decomposition will occur. Over the reach of stream where the dissolved-oxygen concentration is zero, a zone of putrefaction will occur with the production of hydrogen sulfide (H2S), ammonia (NH3), and other odorous gases. Because many fish species require a minimum of 4–5 mg of dissolved oxygen per liter of water, they will be unable to survive in this portion of the stream.

Direct exposures to toxic chemicals are also a health concern for individual aquatic plants and animals. Chemicals such as pesticides are frequently transported to lakes and rivers via runoff, and they can have harmful effects on aquatic life. Toxic chemicals have been shown to reduce the growth, survival, reproductive output, and disease resistance of exposed organisms. These effects can have important consequences for the viability of aquatic populations and communities.

Wastewater discharges are most commonly controlled through effluent standards and discharge permits. Under this system, discharge permits are issued with limits on the quantity and quality of effluents. Water-quality standards are sets of qualitative and quantitative criteria designed to maintain or enhance the quality of receiving waters. Criteria can be developed and implemented to protect aquatic life against acute and chronic effects and to safeguard humans against deleterious health effects, including cancer.

Recycling is essential for improving environmental degradation:

Recycling is essential for improving environmental degradation:

Environmental problems have become so complex that many individuals feel they can have no effect on them. Problems like global warming, hazardous waste, loss of rain forests, endangered species, acid rain, the ozone layer, and the municipal waste crisis can feel out of our control. At the very least, these problems require group and corporate action or government intervention. But there are some things the individual can control. Our waste reduction and recycling activities can make a difference.

Recycling is nothing but reprocessing of old material and converting it to new usable products. Recycling prevents waste of potentially useful materials, reducing consumption of fresh raw material, ore and minerals. Recycling process also economizes over all energy consumption for production of materials than the virgin products; thereby improving environmental degradations. Recycling is a key concept of modern waste management.

The recyclable materials are mostly paper, metal, textiles, glass and plastics. These materials are either brought to a collection centre or picked-up from the curbside, sorted, cleaned and reprocessed into new products bound for manufacturing.

(i) Curbside recycling - Curbside recycling now serves half of the U.S. population, providing the most convenient means for households to recycle a variety of materials. While all curbside programs differ, the most commonly included materials are The Big Five: aluminum cans, glass bottles, paper, plastic and steel/tin cans.

(ii) Electronics - Technology has revolutionized our lifestyle through telephones, radios, TVs, computers and cell phones. However, the brisk pace of technology means these devices become obsolete quickly. A more recent issue is how our old electronics should be disposed of, because they often contain dangerous elements such as lead and mercury that can contaminate our soil and water supply.

(iii) Composting - Managing organic material at your home can not only decrease the amount of material you send to the landfill; it can also help turn your organic waste into a landscape asset. Composting will reduce the amount of food waste in your garbage can, while creating nutrient-rich fertilizer for your garden.

The adverse effects of global warming:

The adverse effects of global warming:

Over last 10000 years temperature remained remarkably stable across the globe, changing by little more than 2 degree Fahrenheit on an average. Even during the ‘Little Ice Age’, which lasted from the 1300 AD to 1850 AD, which resulted advancing of glaciers, average temperatures were little more than 2 degree Fahrenheit. The effects of global warming could change average temperatures five times as much as little ice age did – though in the opposite direction. Over the next century, the rate of the effects of global warming should follow a steep upward curve.

The adverse effects of global warming are enormous. The effects are already being felt on our planet, on human life, plants and animals worldwide. The predicted effects of global warming on the environment and for human life are numerous and varied. It is generally difficult to attribute specific natural phenomena to long-term causes, even though, some effects of recent climate changes already we are witnessing; rising sea levels, glacier retreat, arctic shrinkage, and altered patterns of agriculture are cited as direct consequences. Among secondary and regional effects extreme weather events, expansion of tropical diseases, changes in the timing of seasonal patterns in ecosystems, and drastic economic impact are predicted.

Major adverse effects of global warming are listed below:

1. Polar ice caps melting - The ice caps melting is a four-pronged danger.

(a) It will raise sea levels. There are more than 5,773,000 cubic miles of water in ice caps, glaciers, and permanent snow. According to the National Snow and Ice Data Center, if all glaciers melted today the seas would rise about 230 feet. This may not happen at once; but sea level will rise certainly and consequently, low lying areas will be submerged.

(b) Melting ice caps will throw the global ecosystem out of balance. The ice caps are fresh water, and when they melt they will desalinate the ocean, or in plain English - make it less salty. The desalinization of the gulf current will distort ocean currents, which regulate temperatures. It will give very confusing and irregular pattern of cooling and warming effects in some areas.

(c) Temperature rises and changing landscapes in the artic circle will endanger several species of animals. Only the most adaptable will survive.

(d) Global warming will certainly reduce ice caps substantially. Ice caps are white, and reflect sunlight, much of which is reflected back into space, further cooling Earth. If the ice caps melt, the only reflector is the ocean. Darker colors absorb sunlight, further warming the earth.

2. Increased probability and intensity of droughts and heat waves - Although some areas of Earth will become wetter due to global warming, other areas will suffer serious droughts and heat waves. Africa will receive the worst of it, with more severe droughts also expected in Europe. Water is already a scarce commodity in Africa, and global warming will worsen the conditions.

3. Warmer waters and more hurricanes - As the temperature of oceans rise, so will the probability of more frequent and stronger hurricanes.

4. Spread of disease - As northern countries warm, disease carrying insects migrate north, bringing plague and disease with them.

5. Economic consequences - Most of the effects of global warming will not be good. These effects bring economic consequences badly for almost all the countries of the world.

Discussion on advantages of environment-friendly Nuclear power over fossil fuel and hydropower:

Discussion on advantages of environment-friendly Nuclear power over fossil fuel and hydropower:

Power from nuclear energy can prevent many of the environmental consequences arising out of the use of fossil fuels, hydropower etc. Below we discuss about the disadvantages of power generated from (a) burning of fossil fuels and (b) hydropower – two major sources of power available by many countries at present other than nuclear power.

A. Disadvantages of power generated by burning of fossil fuels, such as coal, petroleum and gas:

(i) The main drawback of fossil fuels is pollution. Burning any fossil fuel produces carbon dioxide, which contributes to the "greenhouse effect", warming the Earth. The effect of rise in temperature is disastrous to environment. Agriculture is very sensitive to climate and hence is heavily affected, requiring shifts in crops that cannot be grown in different areas. Livestock also been affected through problems in breeding, diseases. Eventually, the melting glaciers will cause sea levels to rise – causes loss of habitat land, allows inland penetration of salt water which heavily impacts aquatic life. Burning fossil fuel also produces sulfur dioxide, a gas that contributes to acid rain. Acid rain is destroying forests, making lakes unlivable for fish and degrade ecosystem.

(ii) Mining coal can be difficult and dangerous. Coal mining destroys large areas of the landscape.

(iii) Waste disposal for coal-fired power plant is a major issue. Coal-fired power plant produces large quantity of ashes, which is difficult to handle and store. It destroys and pollutes large areas of land. Dust is also generated, causing health problems to human being.

B. Disadvantages of hydropower: although hydroelectric power is considered to be a clean, renewable source of energy, emitting a very low level of greenhouse gases when compared to fossil fuel plants; it many disadvantages. Disadvantages are listed below:

(i) The flooding of large areas of land means that the natural environment, forest etc., is destroyed.

(ii) It requires water at a certain volume and speed. Rain fall or lack thereof can affect the efficiency of this type of energy source.

(iii) Dams are extremely expensive to build and must be built to a very high standard. The high cost of dam construction means that they must operate for many decades to become profitable.

(iv) People living in villages and towns that are in the valley to be flooded, must move out. This means that they lose their farms and businesses. In some countries, people are forcibly removed so that hydro-power schemes can go ahead. Most of the time rehabilitation of such large number of people becomes very much problematic and some time not possible for whole mass of persons destabilized because of creation of dams.

(v) The building of large dams can cause serious geological damage. There are many examples when big dams are created; it aggravated the chances of earthquake. For example, the building of the Hoover Dam in the USA triggered a number of earth quakes and has depressed the earth’s surface at its location.
(vi) Building a large dam alters the natural water table level of the area.

(vii) Dams built blocking the progress of a river in one country usually means that the water supply from the same river in the following country is out of their control. This can lead to serious problems between neighboring countries.

(viii) It alters the ecology upstream and downstream of the dam, although fish-ladders have some moderating effect on migratory species going upstream, but can chew up the fish on the way down. The diversion of water can impact stream flow, or even cause a river channel to dry out, degrading both aquatic and streamside habitats.

C. Below we discuss advantages of nuclear power vis-a-vis other energy options, especially fossil fuel.

(i) One of the greatest advantages of nuclear power is that it avoids the wide variety of environmental problems arising from burning fossil fuels - coal, oil, and gas. Nuclear energy does not produce smoke or carbon dioxide, so it does not contribute to the greenhouse effect. Thus ‘global warming’ process can be minimized - changing the earth's climate, acid rain, which is destroying forests and killing fish; air pollution etc. Nuclear power checks degrading our quality of life; i.e., the destructive effects of massive mining for coal; and oil spills which do great harm to ecological systems can be prevented.

(ii) It is possible to generate a high amount of electrical energy in one single plant using small amount of fuel.

(iii) Nuclear power is reliable. This technology is readily available; it does not have to be developed first.

(iv) Produces small amounts of waste. As the quantity of waste generated by nuclear power plant is very small, the disposal of radio-active waste can be easily contained so they can be buried deep underground. Also, more effective ways can be found out as our technology is improving at a very fast pace. Moreover, the quality of radio-active waste improved if we go for reprocessing of spent fuel and reuse of plutonium is incorporated.

(v) Nuclear power is also not so expensive as compare to power from coal. Reprocessing and reuse of plutonium from spent fuel makes it even cheaper than coal based power plant. The concern about proliferation should be taken out of mind as there are much easier, faster, and cheaper ways for a nation to develop nuclear weapons than through a nuclear power programme.

D. Discussions on future dependability for production of clean electric power –

(i) As observed from above, nuclear power has advantages in many areas, including some that have been traditionally viewed as problem areas. It averts the pollution, environmental degradation and above all retards generation of greenhouse gases responsible for global warming. It also solves difficult waste management problems.

(ii) In my opinion, the generation of nuclear power should be given most priority, to combat environmental degradation and global warming issues. Wherever there is stagnation in implementing new nuclear power projects, those should be sorted out immediately to get the benefits of nuclear power and to mitigate the global warming process. Any step which mitigates the global warming process has to be adopted immediately, without wasting time, as we may not sustain any more the adverse impact of global warming. Survival of human race is at stake due to global warming.

(iii) In my opinion, if we can generate sufficient clean nuclear power so that our dependence on fossil fuel is reduced to shear minimal – whether for generation of electricity or for transport – the overall environment would be much cleaner.

(iv) Nuclear power may be supplemented by other form of clean energy such as wind energy and solar energy.

(v) For efficient community power backup environment-friendly Sodium-Sulfur (NaS) battery or equivalent should be used extensively along with nuclear power, wind power.

(vi) Transportation including motor vehicles should be run only on clean electric power.

(vii) Another advantage of producing enough nuclear power for the requirement of almost every industry and day-to-day consumption is lesser dependence on bio-diesel, bio-ethanol and other bio-fuel. Use of less bio-fuel means availability of agriculture for more food production – reduction of poverty.

(viii) Research activities should be enhanced in the areas of development of efficient environment-friend batteries and other aspects of nuclear technology.

(ix) As technology advances, we hope to switchover to more environment-friendly nuclear reactor – ‘breeder reactor’ – soon; reducing radio-active waste disposal problem.

(x) Moreover development of FUSION TECHNOLOGY successfully is also not very far; once we do that we have sufficient energy.

Some of the ways to promote waste reduction:

Some of the ways to promote waste reduction:

Below are given some suggestions in order to promote for waste reduction. Changes of some policy decision by the authorities may also necessary for smooth operation of the waste reduction and recycling programme.

1. Promote educational campaigns for (a) environmental and societal benefits of waste reduction and recycling (b) composting options (c) reducing the stigma attaching to waste work.

2. Study waste streams (quantity and composition analyses); recovery/recycling systems; markets for recyclables, and problems of existing practices to decide where there may be a facilitative/regulatory role for the municipal authority.

3. Promote and support source separation, recovery and trading networks of wastes, including NGO projects.

4. Facilitate small enterprises and private-public partnerships by: new or amended regulations for co-operatives, loans to businesses, amendment of counter-productive zoning and tax regulations, enable space for sorting and trading depots, etc.

5. Reduce harassment of itinerant buyers, pickers and waste dealers by police. Assist waste pickers to move out of manual picking through retraining programs or subsidization of sorting/redemption centers.

6. After consulting the major stakeholders, advocate, if feasible, selective waste minimization legislation. Pressure national levels for packaging reduction, product redesign, and coding of plastics.

7. Examine the needs of near-urban farmers for organic matter and support safe waste reuse in urban agriculture; reduce or remove high subsidies of chemical fertilizers.

8. Encourage export of recyclables if there is an economic demand in nearby countries and non-toxicity is assured; remove tax barriers to such trading.

Waste disposal – A burning problem to be resolved to save environment:

Waste disposal – A burning problem to be resolved to save environment:

The disposal of garbage in the world is a problem. This problem continues to grow with the growth of population and development of industries. Disposal of waste in open pits has become routine in majority of places.

Waste can be many different types. The most common methods of classification are by wastes’ physical, chemical and biological characteristics. One important classification is by their consistency, such as solid, liquid and semisolid or sludge.

(i) Solid wastes are waste materials that contain less than 70% water. This class includes such materials as household garbage, some industrial wastes, some mining wastes, and oilfield wastes such as drill cuttings.

(ii) Liquid wastes are usually wastewater's that contain less than 1% solids. Such wastes may contain high concentrations of dissolved salts and metals.

(iii) Sludge is a class of waste between liquid and solid. They usually contain between 3% and 25% solids, while the rest of the material is water dissolved materials.

There are many different methods of disposing of waste; such as Landfills, refuse burning in incinerators etc.

(a) Landfill is the most common and probably accounts for more than 90 percent of the nation's municipal refuse. Landfills have been proven contaminates of drinking water in many areas. Landfills are the most cost affective method of disposal, with collection and transportation accounting for 75 percent of the total cost. In a modern landfill, refuse is spread thin, compacted layers covered by a layer of clean earth. Pollution of surface water and groundwater is minimized by lining and contouring the fill, compacting and planting the uppermost cover layer, diverting drainage, and selecting proper soil in sites not subject to flooding or high groundwater levels. The best soil for a landfill is clay because clay is less permeable than other types of soil. Materials disposed of in a landfill can be further secured from leakage by solidifying them in materials such as cement, fly ash from power plants, asphalt, or organic polymers.

(b) Refuse is also burned in incinerators. It is more expensive but relatively safer method of disposal than landfills. It has also been reported that, garbage burned in incinerators has poisoned air, soil, and water. Modern incinerators are designed to destroy at least 99.9% of the organic waste material they handle. Numerous thermal processes recover energy from solid waste. Companies burn in-plant wastes in conventional incinerators to produce steam. Pyrolysis, a process of chemical decomposition, produces a variety of gases and inert ash. These gases then are used for manufacturing some useful chemicals. Recently, in some countries oil also has been produced successfully from plastic garbage. This conversion is a very useful conversion and we should try to convert plastic garbage into useful oil. Lot of research work is going on at present to make this conversion feasible.

(c) Organic materials that have little or no heavy metals can be detoxified biologically. Composting and land farming, in which materials are spread out over a large land area so that microbes can decompose them, are examples of biological treatment of hazardous waste. If the materials are not detoxified before they percolate into groundwater than obvious repercussions may occur. Composting includes preparing refuse and breakdown of organic matter by aerobic microorganisms.

(d) The practice of recycling solid waste is an old one. Metal implements were melted down and recast in prehistoric times. Today, recyclable materials are recovered from municipal refuse by a number of methods, including shredding, magnetic separation of metals, screening, and washing.

(e) Hazardous wastes pose a danger to humans or other living organisms. Management of radioactive and other hazardous wastes is subject to Govt. regulation. No satisfactory method has yet been demonstrated for disposing permanently of radioactive wastes.

Further discussions on problems waste disposal: There is a strong movement in many countries to reduce the volume of wastes to be dumped. The increase of composting sites is an indication that organic fraction of garbage can be converted into a useful and commercial product with a higher value. For inert materials, technologies are needed to use wastes as raw materials to produce new products. Development of new materials from recycled materials will also encourage sorting of solid wastes. "Zero Waste" movement also targets industries and waste exchange. 40 % of landfilled wastes in most of the countries come from building materials and this suggests that such wastes can be avoided by developing long-lasting materials and dwellings to reduce wastes from need to rebuild. Other alternatives and efforts indicate that

(i) Onsite treatment and utilization will reduce need for transport.

(ii) Waste minimization is a socially desirable goal.

(iii) Subsidy on products generated from recycled materials will encourage socio-economic changes.

(iv) Centers with technologies that use collected waste materials are needed.

(v) Wastes that have severe risks and excessive problems in disposal should be identified and those which cannot be neutralized may need to be restricted at the point of creation or entry.

(vi) A database on wastes that are available will provide information to possible users of wastes.

Sodium-Sulfur (NaS) battery possesses immense advantages to tackle environmental pollution problems:

Sodium-Sulfur (NaS) battery possesses immense advantages to tackle environmental pollution problems:

Until recently, large amounts of electricity could not be efficiently stored. Thus, to tackle the power cut problems industry used to get the services of Diesel Generating (DG) sets. Diesel generating system runs on diesel and, as we know, pollute environment in many ways. Apart, the quality and economy of electricity produced by DG sets are neither upto the standard nor at par with the electricity obtained from state power grid. Moreover, it helps in improving performance of renewable energy plants, specifically wind farms and solar generation plants, by delivering more reliable power.

A new type of large room-size battery, however, may be poised to store energy for the nation's vast electric grid almost as easily as reservoir stockpiles water, transforming the way power is delivered to homes and businesses. In general, the batteries, use for storage of electricity for many purposes, are plagued by limited life spans or unwieldy bulky.

A Sodium-Sulfur battery is a type of battery constructed from sodium (Na) and sulfur (S). This type of battery exhibits a high energy density, high efficiency of charge/discharge (89—92%), long cycle life, and is fabricated from inexpensive, non-toxic materials. Sodium-Sulfur (NaS) batteries are compact, long-lasting and much efficient to handle large power requirements. Using so-called NaS batteries, utilities could defer for years, and possibly even avoid, construction of new transmission lines, substations and power plants. A suggested application is grid energy storage.

The salient features of NaS batteries are:

(a) High energy density (compact);

(b) High charging-discharging efficiency;

(c) Long calendar lifetime;

(d) Environmentally friendly;

(e) Superior operation and maintenance requirements;

(f) Internal operating temperature is nearly 300 degree Celsius.

The advantages of NaS battery are:

(i) Reduce the investment in power plant and transmission and distribution facilities;

(ii) Improve the efficient use of existing power generation and distribution facilities;

(iii) Reduce power transmission losses;

(iv) Improve the reliability of electricity supply;

(v) They make wind power - wildly popular but frustratingly intermittent - a more reliable resource;

(vi) They provide efficient backup power in case of outages.

Above benefits are critical, as power demand is increasing by leaps and bounds everywhere. The NaS battery is the most advanced of several energy-storage technologies. USA and Japan is the leading user of NaS batteries for their power utilities.

Comparison of Sodium-sulfur (NaS) battery with Lead-Acid battery
Properties	NaS battery	Lead-Acid battery
Energy Density (Volume)	170 kWh/m3 (4.2)	40 kWh/m3 (1)
Energy Density (Weight)	117 kWh/ton (5.8)	20 kWh/ton (1)
Charge/Discharge Efficiency	More than 86%	More than 84%
Maintenance	Maintenance free	Regular maintenance
Life	2,500 cycles or more	1,200 cycles

The biggest drawback of NaS bettery, now, is price. The battery costs about $2,500 per kilowatt, about 10% more than a new coal-fired plant. That discourages independent wind farm developers from embracing the battery. Mass production, however, is expected to drive prices down.

Technology: A Sodium-Sulfur (NaS) battery consists of liquid (molten) sulfur at the positive electrode and liquid (molten) sodium at the negative electrode as active materials separated by a solid beta alumina ceramic electrolyte. The electrolyte allows only the positive sodium ions to go through it and combine with the sulfur to form sodium polysulfides.

2Na + 4S = Na2S4

During discharge, as positive Na+ ions flow through the electrolyte and electrons flow in the external circuit of the battery producing about 2 volts. This process is reversible as charging causes sodium polysulfides to release the positive sodium ions back through the electrolyte to recombine as elemental sodium. The battery is kept at about 300 degrees C to allow this process.

Sodium-Sulfur batteries are a possible energy storage application to support renewable energy plants, specifically wind farms and solar generation plants. In the case of a wind farm, the battery would store energy during times of high wind but low power demand. This stored energy can then be discharged from the batteries during peak load periods. In addition to this power shifting, it is likely that sodium sulfur batteries can be used throughout the day to assist in stabilizing the power output of the wind farm during wind fluctuations. These types of batteries present an option for energy storage in locations where other storage options are not feasible due to location or terrain constraints.

Environment friendliness of modern steel:

Environment friendliness of modern steel:

Steel is the world's most recycled material. Steel's unique magnetic properties make it an easy material to recover from the waste stream, i.e., it can be recycled. The properties of steel remain unchanged no matter how many times the steel is recycled. The electric arc furnace (EAF) method of steel production can use recycled steel exclusively.

Most steel is made via one of two basic routes: (1) Integrated (blast furnace and basic oxygen furnace); (2) Electric arc furnace (EAF).

The integrated route uses raw materials (that is, iron ore, limestone and coke) and scrap to create steel. On the other hand, the EAF method uses scrap as its principal input.

The EAF method is much easier and faster since it only requires scrap steel. Recycled steel is introduced into a furnace and re-melted along with some other additions to produce the end product.

Steel can be produced by other methods such as open hearth. However, the amount of steel produced by these methods decreases every year.

Of the steel produced recently, about 65.0% was produced via the integrated route, 32.0% via EAF and 3.0% via the open hearth and other methods.

Steel is not a single product. There are currently more than 3,500 different grades of steel with many different physical, chemical, and environmental properties. Approximately 75% of modern steels have been developed in the last 20 years. If the Eiffel Tower were to be rebuilt today the engineers would only need one-third of the amount of steel. Modern cars are built with new steels that are stronger, but up to 25% lighter than in the past.

Steel is very friendly to the environment. It is completely recyclable, possesses great durability, and, compared to other materials, requires relatively low amounts of energy to produce. Innovative lightweight steel construction (such as in automobile and rail vehicle construction) help to save energy and resources. The steel industry has made immense efforts to limit environmental pollution in the last decades. Energy consumption and carbon dioxide emissions have decreased by one-half of what they were in the 1960s. Dust emissions have been reduced by even more.

Coal-bed methane (CBM) drainage – Environment-friendly & safer system for coal mines operation:

Coal-bed methane (CBM) drainage – Environment-friendly & safer system for coal mines operation:

Over the past few decades, emissions of methane from coal mines have increased significantly because of higher productivity, greater comminuting of the coal product, and the trend towards recovery from deeper coal seams. Under current coal mine regulations of many countries, methane must be controlled at the working faces and at other points in the mine layout. This has traditionally been performed using a well-designed ventilation system. However, this task is becoming more difficult to achieve economically in modern coal mines. In addition, scientists have established that methane released to the atmosphere is a major greenhouse gas, in contributing to potential global warming. In order to improve mine safety and decrease downtime as a result of methane in the mine openings, many mines are now using a degasification system to extract much of the coal-bed methane from their seams before or during mining. Geologists are aware of the depositional environments that can produce coal-bed methane, reducing the cost of extensive exploration.

Methane drainage offers the added advantages of reducing the ventilation costs, reducing the development costs of the mine, reducing the global warming threat, and allowing a waste product to be productively utilized. Coal-bed methane is produced domestically, reducing our need to import energy. And most importantly, methane is a relatively clean-burning source of energy, much cleaner than coal. All of these factors combine to make coal-bed methane a locally-produced, affordable source of energy.

This byproduct can be gathered to produce three levels of benefits to a mining company, depending on the market potential of the methane. The benefit levels are as follows:

(1) The methane is gathered from the coal seam to reduce ventilation costs, downtime costs, production costs, and shaft development costs or to benefit from increased coal resources. All of these benefits are achieved internal to the mining operation and can be easily analyzed by the mining company.

(2) The coal-bed methane is extracted from the seams to be mined and is utilized as a local energy resource to heat buildings, dry coal output from the coal preparation facility, generate electrical power, power vehicles by compressing the gas, or other local uses.

(3) The extracted methane can be upgraded, if necessary, or immediately compressed and introduced into a commercial gas pipeline system. This may provide the highest possible benefit to the mining company providing that the methane is of high quality and the mine location is near a gas pipeline. With this option, the value of the methane as an energy resource may be very large and it can make a significant contribution to profits.

Many have their opinion that, coal-bed methane production results in changes to the land, to surface water, and to ground-water systems. These changes should be monitored and managed in order to reduce their impact. Although they are being challenged, they remain a starting point. With care, it seems that the environmental costs of coal-bed methane can be reduced.

Thus, in general, extraction of coal-bed methane provide lot of economical benefits in running coal mines, apart from providing cleaner environment by preventing release of major greenhouse gas, methane, in the atmosphere and recovering extra energy source as well.

Pollution from Oil refineries:

Pollution from Oil refineries:

Oil refineries pollute our air, water, and land. Oil refineries cause smog and air pollution. Almost all refineries in every country currently pollute at unacceptable, unhealthy levels. Oil refineries emit about 100 chemicals everyday. These include metals like lead which makes it hard for children to learn. They also include very smaller size dust particles that get deep into our lungs and harm our ability to breathe. Finally, refineries emit many gases like sulfur dioxide (SO2), nitrogen oxide (NO2), carbon dioxide, carbon monoxide, methane, dioxins, hydrogen fluoride, chlorine, benzene and others.

Many of the gases emitted by refineries are harmful to humans, and can cause permanent damage and even death. They can cause respiratory problems (such as asthma, coughing, chest pain, choking, bronchitis), skin irritations, nausea, eye problems, headaches, birth defects, leukemia, and cancers. Young children and the elderly are the worst affected.

Sulfur dioxide (SO₂): Crude oil and coal both contain relatively high quantities of sulfur. (Natural gases contain much less sulfur and therefore are safer.) When crude oil or coal is heated at the refinery to produce fuel, the sulfur is converted into a gas called sulfur dioxide. This is a colorless gas with a very strong smell, like rotten eggs.

Bad effects of Sulfur dioxide: Exposure to very high concentrations of SO₂ can result in painful irritation of the eyes, nose, mouth and throat, difficulty in breathing, nausea, vomiting, headaches and even death. Some of the health effects from daily exposure to outdoor levels of SO₂ are tight chests, worsening of asthma and lung disease, and narrowing of air passages in the throat and chest. People with asthma are more sensitive to SO₂. Exposure to SO₂ can provoke asthma attacks. SO₂ mixes easily in water, including moisture in the air to form an acid. Acid rain and early morning dew causes much damage to metals, stones, and the environment.

Fugitive emissions are the air pollution which escapes through leaks in the equipment. Very often the amount of pollution coming from fugitive emissions is higher than the amount coming out of the stacks.

Many of the refineries often use low quality crude oil that has high levels of sulfur. When this is refined it produces higher levels of SO₂ pollution.

Accidental fires, explosions, and chemical and gas leaks are common at refineries. Such accidents cause higher than usual amounts of pollution, which may result in more acute exposure to pollutants and greater health impacts.

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.

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.

Fundamentals of prevention and control of air pollution:

Fundamentals of prevention and control of air pollution:

As mentioned in my earlier discussion, air pollutants can be gaseous or particulate matters. Different techniques for controlling these pollutants are discussed below:

A. Methods of controlling gaseous pollutants -

1. Combustion - This technique is used when the pollutants are in the form of organic gases or vapors. During flame combustion or catalytic process, these organic pollutants are converted into water vapor and relatively less harmful products, such as CO2.

2. Absorption - In this technique, the gaseous effluents are passed through scrubbers or absorbers. These contain a suitable liquid absorbent, which removes or modifies one or more of the pollutants present in the gaseous effluents.

3. Adsorption - The gaseous effluents are passed through porous solid adsorbents kept in suitable containers. The organic and inorganic constituents of the effluent gases are trapped at the interface of the solid adsorbent by physical adsorbent.

B. Methods to control particulate emissions:

1. Mechanical devices generally work on the basis of the following:

(a) Gravity: In this process, the particles settle down by gravitational force.

(b) Sudden change in direction of the gas flow. This causes the particles to separate out due to greater momentum.

2. Fabric Filters: The gases containing dust are passed through a porous medium. These porous media may be woven or filled fabrics. The particles present in the gas are trapped and collected in the filters. The gases freed from the particles are discharged.

3. Wet Scrubbers: Wet scrubbers are used in chemical, mining and metallurgical industries to trap SO2, NH3, metal fumes, etc.

4. Electrostatic Precipitators: When a gas or an air stream containing aerosols in the form of dust, fumes or mist, is passed between two electrodes, then, the aerosol particles get precipitated on the electrode.

C. Apart from the above, following practices also help in controlling air pollution.

(i) Use of better designed equipment and smokeless fuels, hearths in industries and at home.

(ii) Automobiles should be properly maintained and adhere to recent emission-control standards.

(iii) More trees should be planted along road side and houses.

(iv) Renewable energy sources, such as wind, solar energy, ocean currents, should fulfill energy needs.

(v) Tall chimneys should be installed for vertical dispersion of pollutants.

Water pollution, its prevention and control:

Water pollution, its prevention and control:

Water is a key resource for our quality of life. It also provides natural habitats and eco-systems for plant and animal species. Access to clean water for drinking and sanitary purposes is a precondition for human health and well-being. Clean unpolluted water is essential for our ecosystems. Plants and animals in lakes, rivers and seas react to changes in their environment caused by changes in chemical water quality and physical disturbance of their habitat.

Water pollution is a human-induced change in the chemical, physical, biological, and radiological quality of water that is injurious to its existing, intended, or potential uses such as boating, waterskiing, swimming, the consumption of fish, and the health of aquatic organisms and ecosystems. Thus, the discharge of toxic chemicals from a pipe or the release of livestock waste into a nearby water body is considered pollution. The contamination of ground water, rivers, lakes, wetlands, estuaries, and oceans can threaten the health of humans and aquatic life.

Contaminants have a significant impact on aquatic ecosystems. for example, enrichment of water bodies with nutrients (principally nitrogen and phosphorus) can result in the growth of algae and other aquatic plants that shade or clog streams. Direct exposures to toxic chemicals such as pesticides, is also a health concern for individual aquatic plants and animals. Without healthy water for drinking, cooking, fishing, and farming, the human race would perish. Clean water is also necessary for recreational interests such as swimming, boating, and water skiing.

A. Sources of Water Pollution: Sources of water pollution are generally divided into two categories. The first is point-source pollution, in which contaminants are discharged from a discrete location. Sewage outfalls and oil spills are examples of point-source pollution. The second category is non-point-source or diffuses pollution, referring to all of the other discharges that deliver contaminants to water bodies.

Numerous manufacturing plants pour off undiluted corrosives, poisons, and other noxious byproducts to water streams. The construction industry discharges slurries of gypsum, cement, abrasives, metals, and poisonous solvents. The mining industry also presents persistent water pollution problems. In yet another instance of pollution, hot water discharged by factories and power plants causes so-called ‘thermal pollution’ by increasing water temperatures. Such increases change the level of oxygen dissolved in a body of water, thereby disrupting the water's ecological balance, killing off some plant and animal species while encouraging the overgrowth of others. Towns and municipalities are also major sources of water pollution.

In many public water systems, pollution exceeds safe levels. One reason for this is that much groundwater has been contaminated by wastes pumped underground for disposal or by seepage from surface water. When contamination reaches underground water tables, it is difficult to correct and spreads over wide areas. Discharge of untreated or only partially treated sewage into the waterways threatens the health of their own and neighboring populations as well. Along with domestic wastes, sewage carries industrial contaminants and a growing tonnage of paper and plastic refuse. Although thorough sewage treatment would destroy most disease-causing bacteria, the problem of the spread of viruses and viral illness remains. Additionally, most sewage treatment does not remove phosphorus compounds, contributed principally by detergents.

B. Dangers of Water Pollution: Virtually all water pollutants are hazardous to humans as well as lesser species; sodium is implicated in cardiovascular disease, nitrates in blood disorders. Mercury and lead can cause nervous disorders. Some contaminants are carcinogens. DDT is toxic to humans and can alter chromosomes. Along many shores, shellfish can no longer be taken because of contamination by DDT, sewage, or industrial wastes.

C. Prevention and Control of Water Pollution: Sewage should be treated before it is discharged into the river or ocean. This is possible through modern techniques.

Sewage is first passed through a grinding mechanism. This is then passed through several settling chambers and neutralized with lime. Up to this stage, the process is called primary treatment. The sewage still contains a large number of pathogenic and non-pathogenic organisms, and also sufficient quantity of organic matter. The neutralized effluents are sent to UASB (up-flow anaerobic sludge blanket). It is a reactor. In this, the anaerobic bacteria degrade the biodegradable material present in the waste water. This removes foul odor and releases methane, which can be used elsewhere. In this system, the pollution load is reduced upto 85 percent. After this, water is sent to aeration tanks where it is mixed with air and bacteria. Bacteria digest the organic waste material. This is called biological or secondary treatment. Even after the treatment, water is not yet fit for drinking. The harmful microorganisms need to be killed. The final step (tertiary treatment) is, therefore, a disinfection process, to remove final traces of organics, bacteria, dissolved inorganic solids, etc. For tertiary treatment, methods, such as chlorination, evaporation, and exchange absorption may be employed. These depend upon the required quality of the final treatment.

Apart from the above, you should also adopt the following practices:

(i) Waste food material, paper, decaying vegetables and plastics should not be thrown into open drains.

(ii) Effluents from distilleries, and solid wastes containing organic matter should be sent to biogas plants for generation of energy.

(iii) Oil slicks should be skimmed off from the surface with suction device. Sawdust may

be spread over oil slicks to absorb the oil components.