ALCHEMY--THE CHEMISTRY TEACHER BLOG: ENVIRONMENT CHEMISTRY

ENVIRONMENT CHEMISTRY –ELECTIVE COURSE

MODULE—I—ENVIRONMENT

Environment can be defined as—Sum total of all social, economical, biological, physical and chemical factors which constitute the surroundings of man. It is the sum total of the conditions that surround man at any given point in space and time.

I Components of the environment—environment consists of three componenets

1 Abiotic component—this is the non-living component of the atmosphere and consists of 3 parts

a) Lithosphere—this is the solid earth component like soil, mountains etc.

b) Hydrosphere—this is the water component like oceans, rivers, lakes, ground water etc.

c) Atmosphere—this is the covering of gases around the earth

2. Biotic component—this consists of all the living organisms on the earth

3. Energy component—this consists of all the energy on the earth like solar, geothermal, thermoelectric etc.

The biotic and abiotic components together is called BIOME. The community of organisms that interact with each other and with the abiotic component of the environment is called ECOSYSTEM. The study of the interactions between living organisms and between living and non-living components is called ECOLOGY.

II. Types of environment—Types of ecosystems

Permanent and Natural Environment—these operate under natural conditions without interference from any of the biotic components including man. These can be divided into

A) Terrestrial ecosystem—these are ecosystems found on land like forest, desert, mountains, grassland etc

B) Aquatic ecosystem—these are ecosystems found in water like marine ecosystem, freshwater ecosystem etc.

Temporary and natural environment—these are ecosystems which are short lived but operate under natural conditions like temporary ponds that dry up after some time and support organisms which can lie in a dormant state during the dry phase

Artificial or man-made or anthropogenic environment—these include ecosystems created by man like aquariums, farmlands, orchards, dams, houses and other buildings, space ecosystem etc. These are also called HUMAN BIOMES or ANTHROMES.

III. Segments of the environment—the environment consists of four major segments. These are

a) Atmosphere—it is the protective covering of gases surrounding the earth. The major components are—nitrogen, oxygen, carbon dioxide, argon, and other noble gases, methane etc. it serves the following functions

(i) It absorbs harmful solar radiations like cosmic rays, UV rays etc. and allow only relatively harmless IR and radiowaves to pass trough.

(ii) Maintains thermal balance by absorbing part of the IR radiations in sunlight and also those that are reflected back by the earth. These IR radiations are then re-emitted back to the earth’s surface.

(iii) Source of oxygen for living things

(iv) It carries the water evaporated from the seas and other water bdies and brigs it to land as rain thus maintaining the hydrological cycle.

b) Hydrosphere—it includes all the water bodies on the earth like seas, rivers, lakes, wells, ponds, etc. about 97 % of the total water on the earth is in the form of salt water in the oceans and about 2% is in the form of ice in glaciers, high mountains and polar ice-caps. Of the remaining 1% some of it is trapped as dirty water in swamps and marshes.Thus only less than 1% is actually available as fresh water for living organisms.

c) Lithosphere –this constitutes the solid rocks and soil on the earth’s crust which consists mainly of minerals like silicates, aluminates, gypsum, clay etc.

d) Biosphere—this denotes all the living organisms on the earth, on land and in the water and in the air above the earth which interact with each other and with the soil, land water and air.

IV. Biogeochemical cycles

Carbon cycle—carbon is absorbed by living organisms from the atmosphere and finally after a series of processes it is returned back to the atmosphere. This cyclic pathway is called carbon cycle. Green plants take in carbon dioxide during photosynthesis, which is converted to glucose with the help of solar energy and later into proteins and lipids. Thus, plants which use solar energy directly to produce food are called producers. Certain bacteria also use solar energy directly to make food. Animals eat plants and the carbon enters their body. These animals are called primary consumers. Carnivorous animals eat these primary consumers (they are the secondary consumers) and thus the carbon is transferred through the food chain. A part of this carbon in the animals goes back to the atmosphere during respiration. When the plants and animals die and decay the carbon in them returns to the atmosphere by decomposition and combustion. Some of the dead organic matter settles down as sediments which are then converted into either fossil fuels or carbonate rock. The rock returns the carbon during weathering and the fossil fuel during burning.

Nitrogen cycle—nitrogen in the atmosphere is converted to oxides of nitrogen during lightning, which is converted to nitrous acid and nitric acid during rains as follows:

N2 + O2 → 2NO

2NO + O2 → 2NO2

2NO2 + H2O → HNO2 + HNO3

These acids react with the basic materials like lime in the soil to give soluble nitrites and nitrates which is food for plants. Plants covert the absorbed nitrites and nitrates into proteins during their growth. When animals eat plants the protein is broken down into amino acids and reconverted into the proteins required by animals. Part of this nitrogen is excreted by animals as urea, uric acid. When plants and animals die they decay in the soil and are converted to ammonia by ammonifying bacteria. The urea and uric acid is also converted to ammonia. Then the nitrifying and nitrosifying bacteria convert ammonia into nitrates and nitrites respectively which is again recycled for use by plants, or the ammonia is converted back to atmospheric nitrogen by denitrifying bacteria.

Phosphorus cycle—plants and animals require phosphorus in small quantities for their growth. The nucleic acids DNA and RNA and the energy storage molecules ATP, ADP and AMP are all compounds of phosphorus. Plants get the required phosphorus from the phosphorus pool of the soil and animals get the phosphorus from plants.The major source of phosphorus in nature is the phosphate rocks which contain soluble and insoluble phosphates. Other important sources are excreta of fish eating birds (called guano deposits which are found mostly on uninhabited islands in the oceans), and fossil bone deposits of extinct animals.

The phosphorus from all these sources leach into the soil and are taken up by plants and converted to organic phosphates. Animals get the phosphorus from plants. When these organisms die and decay the phosphorus is returned back to the phosphorus pool.

A part of the phosphorus in the soil leaches into rivers and other fresh water bodies fish and so on .There they are absorbed by floating algae (phytoplankton) which are food for the zooplankton. Zooplanktons are eaten by small fish, which in turn are food for larger aquatic animals. When these plankton and fish die they settle to the bottom of the water bodies as sediments. These sediments are decomposed by microorganism and again enter into circulation.

Sulphur cycle—sulphur is a component of amino acids cystein and methionine and as such forms a part of many proteins and vitamins having various functions (methionine is present in all proteins). Thiamine (vitamin B₁) is essential for the peripheralnervous system and contains sulfur. Sulfur can serve as a food to some chemoautotrophic organisms (sulphur bacteria). Sulfur is essential for root nodule formation and defense mechanisms.

Sulphur is present in the atmosphere as sulphur dioxide formed by the combustion of fossil fuels and from volcanic eruptions. This combines with rain water and forms sulphuric and sulphurous acid and is subsequently converted to inorganic suphates in the soil. Plants take up these sulphates and convert it into amino acids, proteins and vitamins. These enter into the animal body through the food chain. When plants and animals die and decay, the organic residue, mainly proteins are leached into water bodies like lakes, rivers or ponds. They are decomposed by bacteria under anaerobic conditions to H2S which is deposited as ferrous sulphide by the Fe2+ present. Under aerobic conditions the H2S is converted into sulphates by sulphur bacteria or oxidized to sulphur dioxide and returned to the atmosphere.

Sulphur may also be present in the soil in the form of elemental sulphur or sulphur minerals. The elemental sulphur is acted upon by bacteria which may convert it into sulphite,and sulphates or into hydrogen sulphide. The H2S is either oxidized by bacteria to SO2 or reduced back to elemental sulphur. The suphate minerals mainly are either oxidized to SO2 or reduced to H2S or elemental sulphur.

VI. World Conferences on Environment

· 1972—United Nations Conference on Human Environment—held during June 5—11, 1972, at Stockholm—first international conference on environment—stockholm declaration –26 principles regarding environmental concerns—109 recommendations laid down the action plan to control and regulate human environment—commemoration of this event we observe June 5 as World Environment Day

· 1982—United Nations Environment Programme—meeting in 1982—10^th anniversary of Stockholm conference—to evaluate the performance since the Stockholm conference

· 1983—Word Commission on Environment and Development—appointed by UN General Assembly—21 countries as members—formulaton of Global Agenda for Change and prepare environmental perspective upto 2000—submitted report ‘Our Common Future’ in 1987. Sustainable development mentioned for first time—meaning meeting the needs of the present without compromising the ability of future generations to meet their own needs.

· 1992—United Nations Conference on Environment and Development (UNCED)—known as Earth Summit and Eco—92—June 3—12, Rio de Janeiro, Brazil. About 170 countries, 500NGOs and 2000 journalists participated—‘Earth charter’ was prepared at this conference sets out rights and obligations of all nations for sustainable development—‘Agenda—21’—action plan for solving environmental problems and tools and resources for implementing action plan—also Convention on Climate Change and Convention on Biodiversity

· 2002—World Summit on Sustainable Development, WSSD or Earth Summit 2002—10 years after Rio Conference –hence also called Rio+10-- Johannesburg, South Africa, from 26 August to 4 September 2002—Johannesberg Declaration—action plan –also agreement to restore worlds’ fisheries by 2015 and partnership initiatives for achieving ‘Millennium Development Goals’

· 2012— The United Nations Conference on Sustainable Development (UNCSD), also known as Rio 2012, Rio+20 or Earth Summit 2012-- Brazil in Rio de Janeiro from 13 to 22 June 2012, Rio+20 was a 20-year follow-up to the 1992 Earth Summit / United Nations Conference on Environment and Development (UNCED) held in the same city, and the 10th anniversary of the 2002 World Summit on Sustainable Development (WSSD) in Johannesburg-- The primary result of the conference was the nonbinding document, "The Future We Want," a 49 page work paper. In it, the heads of state of the 192 governments in attendance renewed their political commitment to sustainable development and declared their commitment to the promotion of a sustainable future. The document largely reaffirms previous action plans like Agenda 21.

VII. Non Governmental Organizations (NGOs)—these are essentially non profit organizations which are set up under different organizations such as public trust, private trust, registered societies, non-profit companies, co-operative societies, trade unions etc. They are legally constituted corporations created by natural or legal people that operate independently from any form of government. The term originated from the United Nations, and normally refers to organizations that are not a part of a government and are not conventional for-profit businesses. In the cases in which NGOs are funded totally or partially by governments, the NGO maintains its non-governmental status by excluding government representatives from membership in the organization

Aims and objectives of Environmental NGOs

Conducting education and citizen awareness programmes in the field of environment

Fact – finding and analysis

Filing public interest litigations

Innovation and experimenting in areas which are difficult for government

agencies to make changes in

Providing factual and reliable information with a network of professional expert staff

Remaining independent while passing relevant information to the public and

governmental bodies

Solidarity and support to environmental defenders

Working in collaboration with the government for capacity building and

promotion of community participation in environmental awareness and

protection and

Working out at the grassroots level and reaching far – flung areas with or

without the government invitation

NGO type by level of orientation:

· Charitable orientation often involves a top-down paternalistic effort with little participation by the "beneficiaries". It includes NGOs with activities directed toward meeting the needs of the poor.

· Service orientation includes NGOs with activities such as the provision of health, family planning or education services in which the programme is designed by the NGO and people are expected to participate in its implementation and in receiving the service.

· Participatory orientation is characterized by self-help projects where local people are involved particularly in the implementation of a project by contributing cash, tools, land, materials, labour etc. In the classical community development project, participation begins with the need definition and continues into the planning and implementation stages.

· Empowering orientation aims to help poor people develop a clearer understanding of the social, political and economic factors affecting their lives, and to strengthen their awareness of their own potential power to control their lives. There is maximum involvement of the beneficiaries with NGOs acting as facilitators.^[7]

NGO type by level of operation:

· Community-based organizations (CBOs) arise out of people's own initiatives. They can be responsible for raising the consciousness of the urban poor, helping them to understand their rights in accessing needed services, and providing such services.

· City-wide organizations include organizations such as chambers of commerce and industry, coalitions of business, ethnic or educational groups, and associations of community organizations.

· National NGOs include national organizations such as the Red Cross, YMCAs/YWCAs, professional associations, etc. Some have state and city branches and assist local NGOs.

· International NGOs range from secular agencies to religiously motivated groups. They can be responsible for funding local NGOs, institutions and projects and implementing projects.

Achievements of environmental NGOs with special reference to WWF (India),Teri, Clean (India), Sulabh International etc.

It is an acceptable fact that no government can enforce environmental laws to keep cities clean. They rely heavily on NGOs to provide the infrastructure for monitoring, creating awareness and taking action. NGOs are playing a very effective role in presenting the various environmental issues before the people and those in positions of authority. It is also an accepted fact that the civic agencies are more amenable to suggestions and advice by people who work in the field of environment. Non-governmental organizations (NGOs) have played a major role in pushing for sustainable development at the international level.

Campaigning groups have been key drivers of inter-governmental negotiations, ranging from the regulation of hazardouswastes to a global ban on land mines and the elimination of slavery. Some of the NGOs which

have been playing an active role, towards protection of the environment and issues, like,sustainable development, both globally and specifically in India need a special referencehere. Following are some of the environmental NGOs in India that have been successful and achieved much in the field of environment protection, conservation and sustainable development. WWF (India)-- is engaged in a multitude of activities for protection and conservation of the environment in the Indian context. Climate change and energy conservation

are among the chief areas of concern for the organisation. The forest and biodiversity onservation division strives to promote and enhance conservation of forest ecosystems in the country through a participatory approach involving key stakeholders. Through its environment education programme, it aims at strengthening individual and institutional capacity in nature conservation and environmental protection through widespread education and awareness. Intimately involved in the conservation of tigers in India since the late 1960s, WWF’s significant efforts culminated in the launch of Project Tiger in 1973. CLEAN-INDIA--Deeply concerned with the deteriorating environmental situation in the country, Development Alternatives initiated the CLEAN-India (Community Led Environment Action Network) programme with five schools in the national capital in 1996. Today, CLEANDelhi has about forty schools regularly involved in monitoring water and air quality in over 150 locations spread across Delhi. TERI (INDIA)--Tata Energy Research Institute (TERI) was formally established in 1974 with the purpose of tackling and dealing with the immense and acute problems that mankind is likely to be faced with in the years ahead :

· On account of the gradual depletion of the earth’s finite energy resources which

are largely non-renewable and

· On account of the existing methods of their use which are polluting

TERI has launched a major project, the first phase of which is near completion. This project is called growth with resource enhancement of Environment and nature (GREEN INDIA-2047)”

SULABH INTERNATIONAL--The Sulabh International Social Service Organisation founded by Dr. Bindeshwar Pathak in the year 1970, is the largest nationally and internationally recognised pan-India social service outfit with 60,000 volunteers on the rolls who work to promote human rights, environmental sanitation, health and hygiene, non-conventional sources of energy, waste management and social reforms through education, training and awareness campaign.

Examples of some NGOs in Calicut

· Lions club of Calicut

· Anveshi Womens Counseling Centre

· YMCA &YWCA

· Prathysa Kendram

· Phinix Pain & Palliative Care

· Amar Jyothy Charitable Trust

· Association for Welfare of Hadicapped

· Society for Protection of Environment, Kerala

· Theeram Samrakshana Samithi

· B P Moideen Seva Mandir

VIII. Current Environmental Issues

( i) Plachimada Agitation

Plachimada is today synonymous with the struggle for right to life through water! There can be no dispute about the need for drinking water to sustain life. Nor can it be disputed that the right of human beings to this most essential need is inalienable. But what happens when a multinational company with tons of money (accumulated mostly through exploitative means world over!) and some people in government greedy for a handful of crumbs (from that loot) join hands?

In the 1970s, Coca Cola was booted from India, albeit for political posturing by a prominent politician. Prior to that, also for political posturing, the term socialist was introduced in the Preamble of the Constitution. Though the Emergency evokes sharp responses in the northern states, Kerala actually took a liking to the discipline it enforced on the work force, especially public servants. Employees actually reached offices on time; red tape and corruption practically disappeared.

Much later, when Mr. P.V. Narasimha Rao took over the reins of the government in 1991, he was forced to mortgage the nation’s gold reserves to turn the economy around. That later became an excuse for uncontrolled foreign investments in India. I recall reading an analysis that had it not been for Narasimha Rao’s political maturity and wisdom, Manmohan Singh’s economic policies would have turned India into another Soviet Union where, following perestroika, people had been forced to queue up for a loaf of bread! Seems prophetic in retrospect!

Unfortunately for Kerala, it was the LDF government led by the CPI (M) that actually invited Coca Cola and Pepsi to invest in the state in 1999, with the promise of practically free water and electricity! Worse, the places these multinationals chose to set up their bottling plants were in the remote areas of Palakkad – Plachimada, an Adivasi belt and Pudussery, an industrial area, both separated by about 10 kms as the crow flies.

Both places fall in rain shadow regions in a state blessed with two monsoons spread over almost 6 months a year and 44 rivers that drain into the Arabian Sea! By a quirk of nature, though the availability of surface water is limited in both places, they are touted to share the second biggest aquifer in the state, and the MNCs had a priori knowledge of this from the satellite images collected by their governments! Activists associated with the struggle at Plachimada clearly remember the full page advertisement taken out by the then LDF government welcoming Coca Cola on setting up its plant at Plachimada! The plant became operational in March 2000.

Within six months, the villagers, saw the level of their water drop sharply, even run dry. The water they did draw, caused diarrhoea and bouts of dizziness. When used for washing , the water gave them rashes and a burning skin. It left their hair greasy and sticky. The women found that the rice and dal didn’t get cooked, but became hard. A thousand families had become directly affected. The pollution came from the sludge, Coca Cola dumped in the area surrounding its plant, which the BBC had tested and declared to have a high content of cadmium and nickel. Coke was passing it off as fertilizer.

Complaints to the authorities not unexpectedly fell on deaf ears. The first protest was launched in front of the company office in February 2002. Finding no positive response from the company or the authorities, an indefinite protest was launched on 22 April 2002, led by Adivasi women Mayilamma and C.K. Janu.

As the protest gained momentum, the protestors – now organized as Plachimada Coca Cola Virudha Samara Samithi or The Plachimada Anti-Coca Cola Agitation Committee – and those supporting them, namely the Plachimada Coca Cola Virudha Samara Aikyadhardya Samithi or The Plachimada Anti-Coca Cola Agitation Solidarity Committee, fine-tuned their demands

Velur Swaminathan, Secretary, Plachimada Adivasi Samrakshana Sangham (Tribal Protection Council) and R. Ajayan, Convener, Plachimada Samara Aikyadardya Samithi (Agitation Solidarity Committee) in February 2009 wrote an Open Letter to former UN Under Secretary General Shashi Tharoor taking exception to his association with the company as a member of the advisory board of Coca Cola India Foundation.

They listed the following charges against the company:

Coca Cola polluted the ground water with deadly toxic and carcinogenic cadmium and lead, which it has not listed under ‘raw materials’, and refused to provide an explanation for their presence.

Coca Cola distributed and spread the deadly toxic and carcinogenic cadmium and lead through its waste sludge and slurry, passing them off as good soil nutrients.

Coca Cola did not supply piped water to the affected families as ordered by the Supreme Court Monitoring Committee on Hazardous Waste.

Coca Cola, as the single largest extractor of ground water and largest transporter of water to other centres through soft drinks, a non-essential luxury good, made the most contribution to depletion of ground water.

All governmental authorities responsible for ensuring that the company functioned within internationally accepted parameters for safety and quality toed the politician’s line and gave false reports intended to help the company. However, well known activists like Medha Patkar visited the place and support for the local agitators kept growing and soon got international attention. Coca Cola was banned in many universities of the United States itself for human rights violations in third world countries!

A BBC team came and took samples of the effluents to the UK and announced that these contained heavy metals like lead and cadmium, far beyond permissible limits. Shockingly, the company was selling these very effluents to innocent farmers as fertilizers!

Around the same time, the Centre for Science and Environment came out with a report that the Cola drinks were themselves contaminated with pesticides. The sale of the colas was banned in the Parliament canteen! With elections round the corner, the local panchayat got into the act. In April 2003, the Panchayat refused to renew the company’s license, which unleashed a series of battles in the courts.

The first petition was allowed by the courts with a direction to the Panchayat to give notice to the company, give it a hearing and then take a decision within 2 weeks. The Panchayat confirmed its decision not to renew the license. The company downed its shutters for the first time on 16 May 2003. It appealed to the Department of Local Self Government which stayed the order of the Panchayat and the company resumed production.

Meanwhile, a Joint Parliamentary Committee was set up to investigate the allegations of pesticides in the cola drinks. It confirmed the allegations of the CSE and BBC and the State Government ordered the company to stop production till the monsoon set in. The company refused and challenged the order in the courts, but was denied the stay it sought. Around this time, the World Water Day was organized at Plachimada. The company then started bringing water in tankers, which was resisted by the people.

It is important to quote two orders of the Kerala High Court here. The first one, by a single judge, held that water is a natural resource and cannot be over-exploited by any single entity. The second, by a division bench, overturned this order stating that ‘the right of a company to draw water from its property even for commercial purposes is the same as the right of an individual to draw water from his property for personal consumption’! The latter went to the extent of directing the Perumatty Panchayat to renew the license within two weeks and told the company that if the license was not renewed within this period, the company could take it as renewed and proceed accordingly!

The Panchayat, under threat of contempt of court, renewed the license conditionally. The three conditions imposed were: [1] no water should be drawn from within the panchayat, [2] the effluents should not be discharged and [3] the company should prove to the panchayat authorities that its products did not have any contamination. The company downed it shutters once again. The matter is now before the apex court.

With neither politicians nor judiciary inspiring confidence, the people of Plachimada had no choice but to persist with their struggle to assert their right over their natural resources. The struggles for justice of the project-affected people of Sardar Sarovar Dam and of the Bhopal Gas leak disaster victims, both on for over 25 years now, teach their own lessons.

Fortunately, Kerala’s political environment is different from the rest of the country and the swinging of fortunes between LDF and UDF helped bring politicians of all hues to Plachimada at some time or other and made them promise support. Both Oommen Chandy and V.S. Achuthanandan did so.

While the UDF wasted its tenure from 2001 to 2006 on blaming the LDF for bringing MNCs into the state, the LDF came back to power in 2006 with the promise of resolving the imbroglio within a month. But its first ban on production and sale of cola drinks was held invalid by the court.

But even while the Coca Cola factory at Plachimada remained closed due to the inability of the company to abide by the conditions set by the Panchayat, the Pepsi company, located in an industrial belt, continued production of soft drinks and over-exploitation of water without any hindrance!

Finally, when the next elections loomed on the horizon, the Achuthanandan government set up a high powered committee to go into the issues at Plachimada. The committee was headed by an additional secretary to the Government of Kerala, K. Jayakumar, and assisted by experts from all relevant fields, the Pollution Control Board, Ground Water Authority etc. The committee submitted its report after nearly a year of intensive efforts. It said the company should be made to pay Rs 216 crore as compensation to the local people and to restore the ecology it had grossly polluted. A tribunal was to be set up to go through the claims and award compensation.

Smack on the eve of elections 2011, the Kerala Legislative Assembly unanimously passed a bill to constitute the tribunal. The Plachimada Coca Cola Victims Relief and Compensation Claims Special Tribunal Bill, 2011, was sent to the Central Government for the President’s assent. Opinion is divided on whether this was required or not. But suffice to say that after holding the Bill for over six months, the Union Home Ministry sent it back to the Government of Kerala seeking certain clarifications. With elections over, fears rose about the actual intentions of the Congress-led UPA at the Centre and the UDF in the State. Coca Cola had already been co-opted to provide drinking water in certain government hospitals in the State.

This has been seen as an effort to project the multinational company as a philanthropic entity amongst the population. Rumour mills have it that a Union Minister from the State had a major role in this effort, though the company itself is known to use all means available, ethical or otherwise, to discredit and even annihilate all opposition to its programs. As part of this effort it has challenged even the competence of the State Government to legislate such a Bill. The two advocates – K.K. Venugopal and Fali S. Nariman – employed to protect the company’s interests have spared no efforts. Fortunately, and thanks partly to the Right to Information Act, knowledgeable people have accessed the contentions of these advocates and repudiated each and every argument, partly blaming the false information on which their arguments were based.

The net effect of these omissions and commissions was that those agitating at Plachimada grew wary of the fate of the Bill and so decided to take the agitation to the next level, almost like Gandhi making salt in defiance of a colonial law. Thus, asserting the ultimate rights of citizens to justice, a march was organized to the company on 17 December 2011, and outwitting the police present in sufficient strength to protect the company and its assets, some of the protestors entered the premises and declared it ‘taken over’ by the people themselves!

Of course, all 22 including 4 women, were arrested. The magistrate granted them bail, but the protestors refused to accept bail and courted arrest. They were remanded for 7 days.

With this, satyagraha was launched in almost every district headquarters besides Plachimada, condemning the arrest and demanding that the state government intervene effectively to get the President’s assent to the Bill. It all seemed to fall on deaf ears. After 4 days in jail, the remanded activists declared they would fast until the government assured them that follow up action on the Bill would be taken up in earnest. They commenced their fast the next day.

Then came another shock - the Minister for Water Resources declared that the State Government had sent the Bill back to the Centre almost a month back, with appropriate explanations! That brought an end to the fast and the satyagraha at district headquarters. When produced before the magistrate on completion of the remand period, the arrested accepted bail and were given people’s receptions at Plachimada, Thrissur and Palakkad. But the battle lines remain.

The next phase could well be a Chengara like situation. In Chengara, landless Adivasis, fed up with false promises from their elected representatives, finally occupied a plantation and even held the police at bay by threatening to commit mass suicide after climbing on to tree tops with nooses around their necks.

Our current rulers can either neglect us as they have done to Irom Sharmila or cheat us as they have done in the cases of the Bhopal Gas victims or Kasargode Endosulphan victims! Chengara has shown one way to deal with such treason. Another way that seems to work is the way of the Naxalites or Maoists whose writ is supposed to run in one-third of the country!

Do we really want to push people into that arena of extremism? What should the ordinary citizen choose between the extremisms of corruption-cum-state terror on one side and opportunist outfits on the other? Whichever choice he makes is hurtful for, as the saying goes, whether the leaf falls on the thorn or the thorn falls on the leaf it is the leaf that will be hurt! But ‘no pain, no gain’ is also a truism!

(ii) Silent Valley – A People’s Movement That Saved A Forest --Here is a gist drawn from an article by the poet Sugatha Kumari in ‘Silent Valley – Whispers of Reason’.

1970: the Kerala State Electricity Board (KSEB) proposes a hydroelectric dam across the Kunthipuzha River that runs through Silent Valley, which will submerge 8.3 sq km of untouched moist evergreen forest.

Arguments it makes for the Silent Valley Hydroelectric Project (SVPH):

1. It will generate electricity for the state of Kerala with the installation of four units of 60 MW each. (The KSEB avers that the state’s electricity requirements will not be met without this additional power).

2. Irrigate an additional 100 sq km in the Mallapuram and Palghat districts.

3. Provide employment to several thousand people during the construction phase and boost the economy of the state.

1971 – 72: Steven Green, a scientist from the New York Zoological Society, conducts studies on primates, especially the lion-tailed macaque in Silent Valley. Green expresses concerns about the possible threats to the rare macaque from the project. Around the same time, herpetologist Rom Whitaker explores Silent Valley to study the snakes of the region. He writes a letter to the Bombay Natural History Society about the need to conserve the Valley. Reports like these alert other naturalists.

February 1973: The Planning Commission approves the project at a cost of about Rs 25 crores. However, due to lack of sufficient funds, implementation is delayed.

Protests begin to mount against the project.

October 1976: National Committee on Environment Planning and Coordination (NCEPC) sets up a task force, chaired by Zafar Futehally, to study the ecological problems that could be precipitated by the project. Work on the project is suspended pending the task force’s impact analysis. Task Force recommends that project be scrapped. However it provides a loophole that stipulates that, if abandoning the project is not possible, a series of safeguards should be implemented. Unsurprisingly, the Kerala government opts to proceed with the project by promising to implement all safeguards. State argues that the area submerged by the dam is only 1022 hectares, of which 150 ha is grasslands. Also argues that only 10 percent of the ecosystem will be damaged, while ecological safeguards will protect the rest.

However, several NGOs strongly oppose the project and urge the government to abandon it. Conservationists argue that:

The entire lower valley will be submerged by the dam, destroying its biodiversity.
The 10 percent loss projected by the government will actually be far worse.
The workforce brought in for the construction of the project will reside in the area for several years and the destruction they cause – illegal wood felling, cattle grazing, poaching, encroaching – will destroy the Valley.

1977: Sathish Chandran Nair visits Silent Valley. He starts a movement to create awareness in academic circles through talks and slide shows. V.S. Vijayan of the Kerala Forest Research Institute does a study on the impact of hydroelectric projects on the environment, and writes to the authorities not to begin the project till his report is submitted. He is warned and his report is suppressed. The message of the conservationists is taken to villages and cities all over Kerala. S Prabhakaran Nair tours the villages of north Malabar; Prof. John Jacob trains young nature lovers. Soon Nature Clubs spring up all over the state. Bit inspite of all this, the state government goes ahead with the project. The result is that the outcry against the Silent Valley Hydroelectric Project – which started as a localized movement through individual and small group protests – goes national and international. The General Assembly of the IUCN urges the Government to conserve the undisturbed forest area. Many eminent people, including conservationists and corporate and political leaders, write to the Central Government requesting that no sanction be given to the project. These include Salim Ali, Madhav Gadgil, CV Radhakrishnan, MS Swaminathan, Subramaniam Swamy, Sitaram Kesari, Piloo Modi and Krishna Kant. Salim Ali writes that the project is ‘shortsighted’ and has ‘limited objectives’. Institutions like the BNHS and Geological Survey of India ask that the area be declared a Natural Bioreserve. However, Prime Minister Morarji Desai rejects all the appeals and recommends that the project begin with no delay.

June 1979: Kerala begins the project in earnest.

August 1979: N.V. Krishna Warrier of the Prakriti Samrakshana Samiti, Prof. Joseph John, and P. Gopalakrishnan Nair, an advocate, file a petition and get a stay order from the High Court of Kerala, stopping work on the project. Soon after, the Silent Valley Samrakshana Samiti and Kerala Sastra Sahitya Parishad start awareness campaigns. They hold protest meetings, rallies and debates all over the state, turning the campaign into a mass people’s movement. Famous writers from Kerala join the movement and contribute their skills: poems, plays, stories and articles, to convey the message to the ordinary citizen. Meanwhile, at the Centre, Morarji Desai is replaced by Charan Singh as PM. He institutes a Central Committee to re-investigate the issue, headed by M.S. Swaminathan,. In a move reeking of money-backed counter-propaganda, the State Government sets up its own panel of environmentalists and scientists who support the government’s views.

January 1980: the High Court rejects the writ plea, saying that it is not for the courts to go into the merits of scientific arguments. Work on the project begins again in earnest. Meanwhile, a small group of campaigners meet the Kerala Governor and request her to issue a stay order against continuing work on the project until the Committee set up by the Centre gives its report. She agrees, and work is halted once again. On the streets, the awareness campaigns continue. The media also plays a role in the campaign against the Silent Valley Project. The newspapers supported the government at first. But later they rallied behind the agitators, extending full support for the conservation of the evergreen rain forest. Meanwhile, in Delhi, Charan Singh’s term as Prime Minister is over in a short six months. He is replaced by Indira Gandhi. She takes an active personal interest in the Silent Valley project, as national and international pressure mounts.

January 1981: Bowing to unrelenting public pressure, Indira Gandhi declares that Silent Valley will be protected. But the area under the hydroelectric project is not covered under the protected area! When the people become aware of this ‘little detail’, hundreds of protest telegrams are sent to the Central Government. More pressure is heaped on the government by NGOs, reputed scientists and intellectuals, and ordinary citizens.

June 1983: the Centre re-examines the issue through a commission chaired by Prof. M.G.K. Menon.

November 1983: the Silent Valley Hydroelectric Project is called off.

1985: Prime Minister Rajiv Gandhi formally inaugurates Silent Valley National Park.

(iii) Chipco Antholan—Chipco means to ‘stick to’ or ‘hug’. On March 26, 1974, a group of peasant women in Reni village, Hemwalghati, in Chamoli district, Uttarakhand, India, acted to prevent the cutting of trees and reclaim their traditional forest rights that were threatened by the contractors assigned by the state Forest Department. They stood in front of the trees and hugged them to prevent the contractors from cutting down the trees. The State Forest Department had auctioned the cutting of 2500 trees in the Reni forest overlooking the Alakananda River, which had already flooded in the rainy season due to destruction of forests. It was one woman Goura Devi who organized the women of her village to protest against the large scale deforestation. Two years later the government imposed a 15 year ban on felling trees in the area. The success of this agitation led to the ban being extended to Himachal Pradesh, Karnataka, Rajasthan, Western Ghats and the Vindhya Mountains. The women also succeeded in preventing the deforestation in the Himalyas. They also set up co-operative societies to guard against felling of trees and to organize fodder production in such a way that trees are not harmed. By the 1980s the movement had spread throughout India and led to formulation of people sensitive environmental policies. In 1987 the Chipko Movement was awarded the Right Livelihood Award. Over time, as a United Nations Environment Programme report mentioned that Chipko activists started "working a socio-economic revolution by winning control of their

forest resources from the hands of a distant bureaucracy which is only concerned with the selling of forestland for making urban-oriented products.". The Chipko movement became a benchmark for socio-ecological movements in other forest areas of Himachal Pradesh, Rajasthan and Bihar; . In September 1983, Chipko inspired a similar, Appiko movement in Karnataka state of India, where tree felling in the Western Ghats and Vindhyas was stopped.

I. Local Environmental Movemnts

In Kerala , various movements have been launched by nature lovers, environmental activists , Adivasis and voluntary organisations against polluting industries, pesticide users and against the construction of dams.

Silent Valley movement of Kerala--In Kerala, public uproar reached its highest peak when the State Government decided to construct a hydro-electric project at Silent Valley in Palakkad district. Later, because of wide spread agitations in the state as well as national and international pressures, the project was completely dropped and the State Government declared Silent Valley as a National Park in 1985.

The Mullaperiyar Dam Issue--The Mullaperiyar dam in Kerala was commissioned in the year 1895. It is constructed over the river Periyar . The dam was constructed with rubble and lime surkhi. Normally for a dam of this type, the life span is 50 years. Now after 111 years the entire structure is unsafe. There was a lease agreement between the State of Travancore and the Madras Presidency in 1886 to supply water to the latter for a period of 999 years. The State of Tamil Nadu has demanded for the raising of water level in the dam so as to get more water for its agricultural lands. Considering the dangerous condition of the dam the Kerala Government did not accept this proposal. The dam is situated at a place which has high seismic potential. So the people of Kerala started agitations demanding for the protection of the dam. So the State government has proposed to construct a new dam that would provide water to the people of Tamil Nadu and remove the fear from the minds of people of Kerala.

Movements against Pollution in river Chaliyar--Complaints of air and water pollution causing serious health hazards had been raised by the people of Kozhikode against the Gwalior Rayons factory at Mavoor. The agitation against the factory became vigourous under the leadership of K. A. Rahman who later died of cancer. The high point of the agitation was in December 1998 when Rahman marched to the factory gates with around 7,000 villagers behind him, demanding its immediate closure. A State Level convention was also held demanding the closure of the polluting unit. On January 20, 1999, ten persons hospitalized after a sulphur dioxide gas leak from the factory. On January 26, the people embarked on a new phase of struggle by starting a relay hunger strike in front of the factory under the leadership of Abdul Salim, Rahman’s son. Kerala’s human rights groups called for a boycott of Grasim products. Ultimately the Kerala State Pollution Control Board ordered the closure of the plant and the polluting plant was closed in 2000.The Chaliyar Agitation against Gwalior Rayons factory is a success story of a people’s environmental movement in the state.

Movement against Endosulfan--Ordinary people of the remote Padre village of Kasaragod district in Kerala along with NGOs have been at the forefront of a battle to ban the use of endosulfan, a toxic pesticide that has been used for decades in India. The impact of spraying is evident in the maimed, mentally and physically disabled children, and in the health of men and women in the 12 villages in the area. The endosulphan spray issue goes back to 1976 when the first experimental aerial spraying was carried out on cashew plantations owned by the plantation corporation of Kerala. This continued for 25 years until it was stopped in 2001 after a tremendous public and media pressure and intervention of the courts. A study conducted by the Centre for Science and Environment highlighting the impacts of endosulfan poisoning on the residents of the area. After the study , government scientific institutions had confirmed this and the use of endosulfan had been banned in the state by Union agriculture ministry.

Movement against Coca Cola--The Hindustan Coca-Cola Beverages Pvt. Ltd established this unit in 1998-99 in a 40-acre plot at Plachimada of Palakkad District, Kerala. Every day 15 million liters of ground water is extracted by Coca Cola at free of cost. Bottle washing involves the using of chemicals and the effluents are released without treatment contaminating the ground water creating a water crisis for the Tribals, Dalits, and the farmers. As the livelihood resources are affected, the employment is also affected pushing them further to the vicinity of the poverty situation. While earlier the foul smelling dry sedimented slurry waste was “sold” as fertilizer to the unsuspecting farmers which was later given “free” and now, with protests and objections, is surreptitiously dumped on the way side and on lands at night The ground water and hence, also water from the open wells has rapidly depleted in this perennially rich paddy growing belt (paddy is abandoned now with the mostly landless Adivasis losing their jobs also). The water turns turbid or milky on boiling and is unfit for drinking, bathing, and washing clothes, etc. The struggle against the Plachimada Plant of Coca Cola was launched on 22 April 2002 with a symbolic blockade and an ongoing continuous picketing/dharna by mainly the Adivasis, particularly by women and children in front the Coca Plant. As struggle progressed hundreds of Adivasis and activists were arrested. The protesters demanded the closure of the Coca-Cola Factory and make it liable for the destruction of livelihood resources of the people and environment. This is not merely a struggle against Coca Cola but all capital that is predatory destroying lives, resources, and environment^.

Greening the State Programme--Scientists are of opinion that the harmful effects of pollution can be minimised if one third of the land area is under forest cover. This awareness has inspired the people and the Government to undertake social forestry programmes so as to increase tree cover .In Kerala the State Forest Department has implemented such programmes with active participation from school and college students. Seedlings have been planted on the sides of roads with the participation of head load workers. Seedlings are also planted on the coast- lines with the help of fishermen community. The Haritha Keralam Programme has been launched with the objective to grow one crore trees outside the forest area with the help of all the 999 Grama Panchayats of the State.

Module—III ATMOSPHERE

Composition of the atmosphere

The atmosphere is made up of a mixture of gases. The major components are O₂, N₂, and water vapour. The minor components are CO₂, and Ar. Trace components are Ne, He, CH₄, Kr, N₂O, H₂, Xe, SO₂, NO₂, NH₃, O_3. The composition remains almost constant upto about 16km. above this height the gravity (weight based) separation of components begins.

The atmosphereextends to a height of about 500km above the earth’s surface and has a mass of 4 — 5 ´10¹³tons^.. The temperature and pressure vary with altitude. The pressure decreases with height but the temperature change depends on many other factors like altitude, presence of gases like ozone etc. The gases surround the earth like a blanket and protect the earth from harmful UV and cosmic radiations coming from the sun. it helps to maintain the heat balance of the earth and also plays a vital role in sustaining life. Any disturbance in the composition of the atmosphere will lead to dangerous consequences.

Major regions of the atmosphere

The atmosphere is made up of 5 concentric regions which are differentiated on the basis of temperature. They are—Troposphere, Stratosphere, Mesosphere, Thermosphere or Ionosphere, and Exosphere.

Troposphere :- This is the region closest to the earth. Extends to a height of 8km near the poles and 11-12 km near the equator. Almost 90% of the total weight of the atmosphere is found in this region. This region is characterized by the steady decrease in temperature with altitude. The temperature decreases at the rate of 6.5°C/ km upto (—60°C) at the top.

This is the most important zone for living beings since it is the region closest to the earth. Oxygen which is essential for animals and plants and carbon dioxide needed by plants for preparing their food are available in the troposphere. This is the region of the atmosphere that determines the weather. It is cloudy, dusty and turbulent with storms and wind. Lightning storms convert nitrogen to oxides of nitrogen which come down to earth as acid rain and are absorbed by plants as nitrates. Greenhouse effect, global warming, acid rain, air pollution—all these problems are important in the troposphere.

Composition—troposphere is mainly composed of O₂, N₂, and water vapour, CO₂, and Ar. Trace components are Ne, He, CH₄, Kr, N₂O, H₂, , SO₂, NO₂, NH₃, O₃.

The uppermost region of the troposphere is called the tropopause and is the boundary between the troposphere and the stratosphere. It extends to a height of 10 to 20 km above the earth’s surface. In the troposphere the temperature was decreasing with height. But now the temperature starts to increase with height i.e there is temperature inversion. The change of temperature with height is called lapse rate. The decrease of temperature with height is called positive lapse rate and increase of temperature with height is called negative lapse rate. The change from positive lapse rate to negative lapse rate is called temperature inversion.

Stratosphere :- the region above the tropopause is called stratosphere. It extends to a height of 50 km. In this region the temperature increases with altitude from –55°C at the bottom to +5°C at the top. This region is rich in ozone which absorbs the sun’s harmful UV radiations and acts like an umbrella protecting the earth. The absorbed UV radiation is converted to IR or heat radiations, which is responsible for the negative temperature lapse in this region.

There are no clouds dust or water vapour and therefore no weather phenomena like wind, snow, rain, hail or storms. It is not at all turbulent—hence very calm. Pollutants that reach this layer are not disturbed and hence remain undecompsed for a very long time. This long residence time leads to long term global hazards like ozone layer depletion.

Composition—the main comstituent of the stratosphere is ozone. It also contains oxygen and nitrogen and small amounts of water vapour.Oxides of nitrogen, CFCs etc. also present due to pollution.

The uppermost region of the stratosphere is called stratopause. The temperature has increased to such an extent that it is almost same as earth’s surface and is not cold.this region reflects sound waves back to the earth’s surface.

Mesosphere :- the region just above the stratopause is called mesoshpere. It extends to a height of 85 km above the earth. The temperature in this region decreases with increase in height i.e positive lapse rate. This is because of the low concentration of gases like ozone which absorb UV and re-emit as IR or heat. The pressure is very low and it reaches a very low temperature of --92°C at the uppermost limit.

Composition—contains nitrogen, oxygen, ozone etc. in small amounts.

The uppermost boundary of the mesosphere is called mesopause. This region has the lowest temperature in the atmosphere—( --100°C ).

Thermosphere or ionosphere :- the region immediately above the mesosphere is called thermosphere. Here the temperature increases rapidly with increase in altitude i.e a negative lapse rate. Maximum temperature could be 1200°C. The air is vary thin and the pressure and density are v. v low. There are very few molecules per unit volume. Therefore we would not feel the high temperature.

The gases present in this region absorb solar radiation and get converted to ions—O₂⁺, O⁺, NO⁺ etc.

It is this layer which reflects the long distance radio waves and thus makes radio communications possible. The meteors get burnt in this layer due to the high temperature. Auroras are seen in this very layer.

Exosphere :- the outermost region of the Earth's atmosphere, beginning at an altitude of approximately 550 km to 700 km and merging with the interplanetary medium at around 10,000 km.The exosphere consists chiefly of ionized hydrogen, which creates the geocorona by reflecting far-ultraviolet light from the Sun. On the remote edges of the exosphere, hydrogen atoms are so sparse that each cubic centimeter might contain only one atom; furthermore, the pressure and gravity are weak enough that atoms in the exosphere can escape entirely and drift into space. Artificial satellites generally orbit in this region

Ions, Radicals and Particulates in the Atmosphere

Ions –present mostly in the ionosphere and produced by the action of UV radiations. Positive ions like O₂⁺, O⁺, NO⁺ etc. and electrons formed, which recombine at night to give neutral molecules. In the ionosphere air is very thin so ions formed also less and mostly formed in the lower regions of the ionosphere.

Radicals—produced due to photochemical reactions and include organic and inorganic species like HO˙, CH₃˙, SO₂˙, ROO˙, NO₂˙, HCO˙ etc. Highly reactive and interact with other species in the atmosphere and are main cause of photochemical smog.

Particulates—these include dust, smoke, fog, pollen, volcanic ash and bacteria with sizes ranging from 0.1 to 10μ. They may enter the respiratory tract and cause respiratory problems. Formation of some of the particles is as follows:-

Dust, smoke, mist, smog, fumes—anthropogenic activities (man made , not natural.)

Iron oxide, calcium oxide and other particulates—burning of coal, metallurgical processes

Lead particles—automobile exhaust

Aerosol mists—SO₂photochemically oxidized to SO₃ to form droplets of H₂SO₄

Organic particulates—automobile exhaust, evaporation of organic matter from trees and plants and contain carcinogenic substances like polycyclic aromatic hydrocarbons.

Effects of particles in the atmosphere

· Helps to maintain heat balance of the earth

· Provide nucleus for condensation of water vapour resulting in formation of fog, mist, cloud

· Helps to bring about reactions in the atmosphere by providing inert particles for three body collisions e.g the reactions leading to formation of acid rain and ozone depletion and photochemical smog.

· Absorb and destroy free radicals

Chemical and photochemical reactions in the atmosphere [O₂, N₂, N₂O, CO₂, O₃ SO₂]

· Oxides of nitrogen—nitrous oxide formed during biological processes, NO and NO₂ from combustion of fossil fuels and also during lightning. These undergo photochemical reaction in presence of UV radiations to give nitric acid as the final product. During this reaction they also cause large scale destruction of ozone layer.

N₂ + O₂→2NO

2NO +O₂→ 2NO₂

NO₂ + hv → NO + O

O₂ + hv → O + O

O + O₂ + M→ O₃ + M

NO + O₃→NO₂ + O₂

NO₂ + O₃ →NO₃ + O2

NO₃+ NO₂→ N₂O₅

N₂O₅ + H₂O → 2HNO₃

HNO2 and HNO3 formed during in these reactions undergo photochemical decomposition to give back oxides of nitrogen and generate dangerous free radicals like H˙ and HO˙.

HNO₂ + hν → NO₂ + H˙

HNO₂+ hν → NO + HO˙.

HNO_{3 +}hν → NO₂ + HO˙.

· Oxides of sulphur—formed in the atmosphere due to combustion of sulphur containing fuels, from refineries, manufacture of H₂SO₄ etc. mainly consists of SO₂, which is oxidized to SO₃ photochemically, catalytically by the oxides of nitrogen present in the atmosphere or by atmospheric ozone.

SO₂ + O₃ → SO₃+ O₂

SO₃ + H₂O → H₂SO₄

SO₂+ 1/2O₂ + H₂O → H₂SO₄ [catalysed by of nitrogen and hydrocarbons]

SO₂+ hν → SO₂˙

SO₂ + O₂ → SO₄˙

SO₄˙ + O₂ → SO₃ + O₂

SO₃ + H₂O → H₂SO₄

· Carbon dioxide—the main effect of carbon dioxide in the atmosphere is the greenhouse effect and global warming. Formed due to combustion reactions, by decay of carbonaceous minerals and during respiration of animals and plants. Most of the carbon dioxide is used up plants during photosynesis, some of it is dissolved in water to give a weak acid—carbonic acid, which dissociates to give bicarbonate ion and hydrogen ion. The hydrogen ion is responsible for the weathering of rocks leading to the formation of sand and clay. The bicarbonate ion is used by marine organisms like shellfish to precipitate carbonates for making their shells.

6CO₂ + 6H₂O + sunlight → C₆ H₁₂O₆ + O₂

O₂ + C₆ H₁₂O₆ → energy + 6H₂O + 6CO₂

CO₂ + H₂O → H₂CO₃

H₂CO₃ + H₂O + silicate minerals → HCO₃^- + cations (Ca⁺⁺, Fe⁺⁺, Na⁺, etc.) + clays

Ca⁺⁺ + 2HCO₃^- → CaCO₃ + CO₂ + H

Major air pollutants

1. Oxides of carbon

§ Carbon monoxide –this is formed due to incomplete combustion of carbon containing materials e.g. automobile exhaust, forest fires and industrial operations. Soil microorganisms act as a sink for carbon monoxide. They use up large quantities of the gas and prevent its large scale increase. CO is highly toxic to human beings. The maximum permissible dose is 8 ppm in the atmosphere for an exposure of 8 hours. It is also potentially harmful to heart patients and could be the cause of heart disease among cigarette smokers.

CO concentration is high in the thickly populated cities due to the increased number of vehicles and the decreased area of soil available as sink

Exposing patients to oxygen at high pressure is the preferred treatment for CO poisoning. This helps to rapidly remove the CO from the haemoglobin.

§ Carbon dioxide—this gas is normally not considered a pollutant. But large increase in CO₂ lead to greenhouse effect and global warming and therefore it increase should be prevented. This can be done by reducing the burning of fossil fuels and use of alternate energy sources like solar and wind power, use of hydrogen fuel or solar energy in automobiles or y the use of battery powered vehicles.

2. Oxides of sulphur – these give rise to sulphuric acid and also some free radicals which are very harmful, leading to the formation of acid rain and photochemical smog.

SO_x emission can be controlled by:

3. Removing sulphur content before fuel is burnt with the help of techniques such as coal cleaning, coal gasification and desulphurization of liquid fuels.

4. Removing SO_x from flue gases before letting them out into the atmosphere. Chemical scrubbers such as a)Limestone or b) Citric acid can be used to absorb SO2 from flue gases.

a) 2CaCO₃ +2SO₂ +O₂ →2CaSO₄+ CO₂

b) SO₂+ H₂O →HSO₃ + H+

HSO₃- + H₂Cit-→(HSO₃.H₂Cit)-₂

· Utilizing low Sulphur fuels.

· Generation of power by alternate energy souces and discouraging fossil fuel based thermal plants.

3. Oxides of nitrogen—these give rise to nitric acid and freeradicals and cause acid rain and photochemical smog. These can be controlled by:

· NO_x from automobile emissions can be converted by using 2-stage catalytic convertors

· NO_x from power plant emissions –reduced by using a 2-stage combustion process

Ist stage: Fuel can be first fired at a relatively high temperature using only about 90 % of stoichiometric air required so that only a minimum quantity of NO is formed under these conditions

2nd stage: Combustion of fuel may be completed at a relatively low temperature ,in the excess of air. NO is not formed under these conditions

· NO_x emission from stationary combustion sources—reduced by modification of operating conditions. NO_x from mobile combustion sources are reduced by lowering the combustion temperature in the engines and catalytic removal of NO_xfrom exhaust gases.

4. Particulates –these are formed due to natural and anthropogenic activities. Can cause severe respiratory problems like breathing problems, lung irritation, fibrosis in asbestos workers, black lung disease in coal miners, emphysema etc. They provide the surface for a large number of undesirable reactions and also lead to decrease in visibility. They can be removed from waste gases in industries by scrubbing the gases with water, using Cottrell precipitator, settling chambers etc.

5. Photochemical smog—oxides of nitrogen, hydrocarbons and other organic compounds present in the atmosphere undergo photochemical reactions to produce leading to the formation of ozone, peroxides and other photochemical oxidants. This gives rise to the formation of aerosols which reduce visibility because of the formation of a brown haze which irritates the eyes and lungs and cause damage to vegetation and rubber goods. This is an oxidizing fog and is different from the reducing fog formed due to a mixture of smoke and water vapour. NO₂ in the atmosphere, in presence of UV radiations undergoes photochemical decomposition giving atomic oxygen. This reacts with the hydrocarbons in the exhaust gases to enerate free radicals which also leads to the formation of ozone peroxides and other reactive free radicals.

· To form photochemical smog, three main ingredients are needed: nitrogen oxides (NOx), hydrocarbons, and energy from the sun in the form of ultraviolet light (UV).

· The first thing that starts the chain of events is that people start driving in the morning. As gasoline is burned, nitrogen (N₂) in the atmosphere is also burned, or oxidized, forming nitric oxide (NO) N₂ + O₂→2NO

· Carbon monoxide (CO) and volatile organic compounds like acetaldehyde,
_{formaldehyde, ethylene will also be emitted by cars. In the air,
nitric oxide combines}_{with molecular oxygen to form nitrogen dioxide within a
few hours.}_{_{2NO + O₂}→_2NO₂}

· Nitrogen dioxide absorbs light energy and splits to form nitric oxide and atomic oxygen: NO₂ → NO + O

· Then, in sunlight, the atomic oxygen combines with oxygen gas to form ozone (O3):
O+ O₂→O₃

· If no other factors are involved, ozone and nitric oxide then react to form nitrogen dioxide and oxygen gas.O₃ + NO → NO₂ + O₂

· This last reaction can go in either direction, depending on temperature and the amount of sunlight. If there is a lot of sunlight, the equation moves to the left, and more ozone is produced. If nothing else gets in the way, an equilibrium is reached, and the ozone level stabilizes.

· However, there is something else involved. Remember that the cars are also emitting hydrocarbons as well as oxides of nitrogen. Hydrocarbons are the other main ingredient in photochemical smog. When hydrocarbons are present, nitric oxide reacts with them instead of the ozone. This reaction produces a variety of toxic products, such as a volatile compound known as PAN (peroxyacetyl nitrate).

· NO + hydrocarbons → PAN and various other compounds. Also,

· NO₂ +hydrocarbons → PAN and various other compounds

· So, there are two results (at least) from the reaction of nitrogen oxides with hydrocarbons. One is that a lot of volatile, reactive organic compounds are generated directly. The other is that when the nitric oxide (NO) is busy reacting with hydrocarbons, it is not reacting with ozone to break it back down to molecular oxygen. So the amount of ozone in the air increases. With nitric oxide reacting with hydrocarbons, ozone may accumulate to damaging levels.

· The result, then, is an accumulation of ozone and volatile organic compounds such as PAN. These are referred to as secondary pollutants, because they are formed by the reaction of primary pollutants, nitrogen oxides and hydrocarbons, emitted by burning fossil fuels. The energy from the sun moves the reactions along. This forms photochemical smog, the brown gunk we see in the sky, especially on hot sunny days.

· Photochemical smog can cause eye irritation and poor visibility. Strong oxidants such as ozone can damage the lungs. The oxidants irritate the linings of lungs. Damage to the lungs may stress the heart. Health damage is worse for people with existing lung and heart conditions. Other health implications may include loss of immune system function, increased susceptibility to infections, and fatigue. The damage can be caused by exposure to large amounts of the pollutant over a short time span, and also by chronic exposure to small amounts over long periods of time. Oxidants can kill plant cells, causing leaves to develop brown spots or drop off the plant, reduce plant growth, and make plants more susceptible to damage from other causes. Oxidants such as ozone can also corrode and destroy many materials such as rubber, nylon, fabric, and paint.

6. Metallic pollutants—metals like Arsenic, Cadmium, Chromium, Lead, Zinc, Nickel, Mercury etc. are produced in the atmosphere due to many industrial activities. Arsenic is produced from fungicides, pesticides etc, Cadmium mainly comes from electroplating and welding and from jewellery works and also from battery manufacture and nuclear reactors. Main source of chromium are metallurgical and chemical industries, lead from automobile emissions, zinc from zinc industries and galvanizing processes and mercury comes from metallurgical processes, mining, laboratories and pesticides.

Adverse effects of metal pollutants on health

Arsenic—it causes nasal irritation and dermatitis when inhaled or

absorbed through skin. Carcinogenic

Cadmium—inhalation of fumes damages heart kidney, lungs intestines liver brain. It is carcinogenic. Chronic and acute poisoning may result.

Chromium—toxic to body tissues. Causes ulcers, skin problems, perforation of nasal septum.

Lead—it is a very toxic substance. Can cause liver and kidney damage, mental retardation in children, foetal abnormalities etc.

Mercury—this also is a very toxic substance. Can cause irreversible damage to nervous system and brain

7. Radiation –radiation in the atmosphere comes from radio active isotopes of uranium, thorium, polonium, radon, etc. These are released into the atmosphere from natural and man made sources like cosmic rays, radioactive elements present in the earth e.g. monazite sands present in certain beaches, radon present in certain rocks which when used for making houses leads to indoor radiation levels and from man made sources like nuclear power generation, use of radio-isotopes in medical applications etc. TV, air travel and other modern amenities like microwave oven, mobile phones, computers etc. are also sources of radiation.

Radiations damage lung tissues and also lead to lung cancer. They may enter the body through the respiratory tract due to inhalation, the digestive tract by ingestion and also cause damage due to exposure of skin to radiation.

8. Petroleum –The combustion of petroleum products and other hydrocarbon fuels in automobiles, trucks, and jet airplanes produces several primary pollutants: nitrogen oxides, gaseous hydrocarbons, and carbon monoxide, as well as large quantities of particulates, chiefly lead. In the presence of sunlight, nitrogen oxides combine with hydrocarbons to form a secondary class of pollutants, the photochemical oxidants, among themozone and the eye-stinging peroxyacetylnitrate (PAN). Nitrogen oxides also react with oxygen in the air to form nitrogen dioxide, a foul-smelling brown gas. In urban areas like Los Angeles where transportation is the main cause of air pollution, nitrogen dioxide tints the air, blending with other contaminants and the atmospheric water vapor to produce brown smog. Although the use of catalytic converters has reduced smog-producing compounds in motor vehicle exhaust emissions, recent studies have shown that in so doing the converters produce nitrous oxide, which contributes substantially to global warming. Petroleum refineries are responsible for extensive hydrocarbon and particulate pollution.

9. Chlorofluorocarbons –these are responsible for depletion of ozone layer and they are also green house gases which contribute towards global warming. They are released into atmosphere by aerosol sprays, freons used as refrigerants etc.

PROBLEMS CAUSED BY ENVIRONMENT POLLUTION

ACID RAIN

We know, there are a lot of air pollutants—oxides of Nitrogen and Sulphur are most dangerous among them. The falling rain and snow react with these oxides, and as a result,sulphuric acid, nitric acid and water are produced through a series of chemical reactions in the presence of light, water, oxygen, heavy metal ions, organic oxidants etc. in the atmosphere These acids come down to earth during rain and is known as acid precipitation or acid rain.

Main causes of acid rain are oxides of nitrogen and sulphur from automobile exhausts.

Oxides of Nitrogen (NO_x)

N₂O,NO,NO₂--- important constituents of atmosphere. The concentration of N₂O is more in the atmosphere but NO₂ and NO are more significant—together they are called NO_x.

At very high temperatures,N₂ and O₂ are combusted in a process involving air e.g during lightning

N₂ + O₂ → 2NO

2NO +O₂→ 2NO₂

NO₂ + hv→ NO + O

O₂ + hv → O + O

O + O₂ + M → O₃ + M

NO + O₃→ NO₂ + O₂

NO₂ + O₃ → NO₃ + O₂

NO₃+ NO₂→N₂O₅

N₂O₅ + H₂O → 2HNO₃

Oxides of N₂ are formed by combustion of coal, oil, natural gas and other organic matter . Automobile exhausts, incinerators, furnace stacks, coal based power plants etc. are main causes of NO_x release. When fuels are burnt in air, some of the N₂ in the air is oxidized to NO. Higher flame temperatures and rapid cooling of combustion products to favour formation of NO. The NO formation in urban areas is 100 times more than in rural areas.

Oxides of sulphur (SOx)

(SO₂ + SO₃) --- Together called SOx

67% of global SOx --- volcanic activity and other natural sources

33%--- man made sources—combustion of fuels, coal fired power stations, transportation, refineries, manufacture of H₂SO₄ etc.

SO₂ is oxidized to SO₃ by ozone ,NOx and hydrocarbons

SO₃ reacts with water vapour to produce droplets of H₂SO₄aerosol which give rise to acid rain. Sulphuric acid and sulphate aerosols present in urban air are much smaller and they easily reach the pulmonary region of lungs, causing serious respiratory problems

SO₂ + O₃ " SO₃+ O₂

SO₃ + H₂O " H₂SO₄

SO₂+ 1/2O₂ + H₂O " H₂SO₄ " (H₂SO₄) n

Adverse effects of acid rain

· Buildings, sculptures carved from marble,limestone,sandstone etc. and stone statues of countries like Greece and Italy are damaged

CaCO₃+ H₂SO₄ " CaSO₄ + H₂O+ CO₂

As a result , the structures become pitted as the soluble salts formed are leached out by rain water. The Taj Mahal in Agra also faces such a threat at present

· Soil acidification affects soil fauna and nitrogen fixation and forest productivity is reduced.High concentrations of sulphuric acid produce necrotic blotching of broad-leaved plants and grasses. Also this acid is harmful for the production of chlorophyll which causes leaf injury and plants may lose their green colour .Acid rain increases acidity of soil and thereby causes serious damage to agricultural crops.

· Acidification affects aquatic life also. Water in ponds,tanks,lakes and rivers are acidified, as a result,fishes and other aquatic life are eliminated in such regions.

· Corrosive damage to steel,zinc,oil based paints and automobile coatings

· Acid rain destroys materials like fabric,paper,etc.

· Effects on humans: Acid droplets in air as well as acid- contaminated water cause neurological, digestive and respiratory diseases in humans. Lungs, hair and skin may be affected very badly. Heavy metals released by acid rain may also cause potential threat to human health

( NOTE: Sulphuric acid rain,however,reacts with ammonia emitted bybiological processes to form (NH₄)₂SO₄, an effective chemical fertilizer )

Steps to control acid rain:

First step is to control emission of NO_x and SO_x

· NO_x from automobile emissions can be converted by using 2-stage catalytic convertors

· NO_x from power plant emissions –reduced by using a 2-stage combustion process

Ist stage: Fuel can be first fired at a relatively high temperature using only about 90 % of stoichiometric air required so that only a minimum quantity of NO is formed under these conditions

2nd stage: Combustion of fuel may be completed at a relatively low temperature ,in the excess of air. NO is not formed under these conditions

SO_x emission:

· Removing sulphur content before fuel is burnt with the help of techniques such as coal cleaning, coal gasification and desulphurization of liquid fuels.

· Removing SO_x from flue gases before letting them out into the atmosphere. Chemical scrubbers such as a)Limestone or b) Citric acid can be used to absorb SO₂ from flue gases.

a) 2CaCO₃ +2SO₂ +O₂" 2CaSO₄+ CO₂

b) SO₂+ H₂O " HSO₃ + H+

HSO₃- + H₂Cit- " (HSO₃.H₂Cit)-₂

· Utilizing low Sulphur fuels.

_·Generation of power by alternative energy sources and discouraging fossil fuel based thermal plant

OZONE LAYER DEPLETION

Ozone is present in the stratosphere. It is an important chemical species. At an altitude of about 30 km,its concentration is about 10ppm.This ozone which envelopes lower atmosphere is called ozone layer or ozone umbrella, as it acts as a protective radiation shield for living organisms on earth against harmful uv radiation. UV radiations of 220-330 nm are absorbed by ozone layer and protect animal and plant life from severe radiation damage such as DNA mutation and skin cancer. Thus only small fraction of UV radiation reaches lower atmosphere and earth’s surface. By this process, it also warms the atmosphere through its exothermic decomposition and thereby maintains the thermal balance of earth.

Ozone formation

O₂ +hv (242nm) " O +O

O+O₂+M (Third body such as N₂ or O₂) " O₃ + M

The third body absorbs excess energy liberated by the above reaction and thereby ozone molecule is stabilized.

Ozone depletion

Holes of various sizes have appeared in ozone umbrella at various regions due to depletion of ozone.

Major contributor of this depletion—CFCs or freons. Mainly, Freon-1 (CFCl₃), Freon-12 (CF₂Cl₂). They are used in aerosol spray cans,refrigerants,fire fighting reagents. Freons are highly stable and inert in troposphere, but slowly diffuse into stratosphere and generate chlorine free radicals due to action of UV light. Each Cl˙ converts ozone molecule back to oxygen. Hence mass depletion of ozone layer results.

Other contributors are NO_x, Atomic oxygen and reactive hydroxyl radical.

NO_x comes from chemical and photochemical reactions in atmosphere, supersonic jets, nuclear explosion etc. High temperature produced in nuclear explosion tests causes oxidation of N₂ to NO which causes ozone depletion

Hydroxy radicals are formed by biomass burning and from natural water system

NO₂ +uv " NO + O

NO + O₃" NO₂ +O₂

NO₂ +O " NO + O₂

This cycle destroys about 70% of ozone in stratosphere.

O₃ + O " O₂ +O₂

O₃+ HO˙ " O₂ + HOO˙

HOO˙+ O " HO˙+ O₂

A long chain process is involved regenerating Cl.

Cl˙ + O₃ " ClO˙ + O₂

ClO˙ + O₃" Cl + 2O₂

The problem is most serious at poles where low temperature prevails. ClO˙ radicals are usually eaten up by NO₂ present in atmosphere and decomposition of ozone is retarded normally . But at low temperature NO₂ solidifies and is not available for eating up of ClO˙ radicals. Also, ice crystals in the clouds over the poles provide a convenient surface and acts as catalysts for photochemical reactions involving the decomposition of ozone by Cl˙ and ClO˙ radicals.

Impacts

· Exposure to UV B-rays causes skin cancer. It is estimated that a 1% reduction in ozone may cause as much as 6% increase in skin cancer.

· Also causes Leukemia and breast cancer.

· UV absorbed by cornea and lens in eyes causes Photokeratitis and cataract without the person even knowing about it.

· Another disastrous impact—Agricultural crops yields are reduced. Exposure to UV decreases Chlorophyll content of leaves of plants leading to a decrease in photosynthesis and damage to the leaves

· Destruction of aquatic organisms as they’re unable to withstand the increased exposure to UV radiation

· Serious climatic changes on earth

Remedial measures

Important remedial measure is to cut off the use of CFCs. In the distant future,we may be able to stop the use of CFC completely In the year 1987, Montreal Protocol was signed by 24 nations which aims at 35% reduction in global production of CFCs by the year 1999. Synthesis of effective substituents to CFC like HFC-134a is reported. Alternatives to CFCs are hydro fluorocarbons (HFCs),hydrochloroflourocarbons (HCFCs) and methyl cyclohexane (MCH

Greenhose Effect and Global Warming

Earth absorbs solar energy mainly as radiations in the visible region and some of the heat that is absorbed by the earth is radiated back to space. There are greenhouse gases in lower atmosphere which prevents sun’s harmful uv radiations from entering the earth, and thus protects earth. But when earth radiates some heat back to space, these gases acting like a glass absorb long wavelength radiations but allow the passage of short wavelength radiations. These long wavelength infrared radiations absorbed by greenhouse gases are re-emitted to earth’s surface. As a result, the earth’s surface increases that is, a heating up of earth’s surface and atmosphere results This phenomenon is called greenhouse effect. This leads to an increase in average global temperature if the concentration of greenhouse gases is higher and causes Global warming.

But we need greenhouse gases to keep earth warm and to sustain life on earth. If the concentration of greenhouse gases is very low, then global temperature falls. But if they exceed a certain limit, excessive trapping of heat threaten the existence of life on earth. Hence we should be able to keep the concentration of greenhouse gases to a certain desired limit.

Causes

CO₂, H₂O, Methane, CFCs etc. are major greenhouse gases.

CO₂: Though not considered as a pollutant, carbon dioxide is a major greenhouse gas. It is produced by respiration, volcanic eruption, burning of fossil fuel, decomposition of CaCO₃.Trees are major sinks for CO₂, as they use up CO₂ during photosynthesis, and replace it with oxygen . So deforestation is the major cause of increase in CO₂ level in the atmosphere. Oceans and biomass also acts as sinks for CO₂.

Methane: Released from coal mines, decomposition of organic matter in swamps, rice paddy cultivation

Chlorofluorocarbons: Used as coolants in refrigerants, propellants in aerosol spray automobile air conditioners.

Hence the main causes of global warming are

· Deforestation

· Excessive use of automobiles

· Industrial revolution

· Burning of fossil fuels and other anthropogenic activities

There is an increase in CO₂content by 25% during last 2 centuries—result is slight increase in temperature by 0.5 degree. It is expected that within next 50-100 years, concentration of greenhouse gases double leading to an increase in average global temperature by 4-5 degree.

Consequences:

· Even 1.5 degree rise in surface temperature will adversely affect food production on earth. Sudden climatic changes upset the agricultural pattern and a drop in food production results.

· Increase in oceanic temperature may cause melting of polar ice caps, leading to an abnormal rise in sea levels around the globe. This may result in soil erosion and submergence of low-lying coastal lands and islands.

· Breeding of pests spreads infectious diseases like dengue, malaria, yellow fever and sleeping sickness.

· Fish and other aquatic organisms may not be able to withstand the high temperature of waters. So they’ll perish.

· Climatic changes resulting in either flood or drought, agricultural loss, homelessness and starvation produces refugees and these people causes serious social and economic problems.

Steps to minimize greenhouse effect:

· Reduction in the use of fossil fuels, encouraging the use of alternative sources of energy (solar, geothermal, wind, biogas etc.)

· Conservation of forests—Extensive afforestation and encouraging community forestry.

· Reduction in the use of automobiles

· Research in development of more efficient automobile engines

· Ban on CFCs and nuclear explosions

· Development of environment-friendly technologies and promoting environmental education

Module-IV-SOLID WASTE MANAGEMENT

ORIGIN

1. Domestic waste- kitchen waste, paper, plastic, clothes etc.

2. Municipal waste-

a) Garbage & rubbish from household, hotels, offices, markets, streets.

Garbage-Biodegradable waste

Rubbish-Not biodegradable. Waste such as paper, cloth, plastic (combustible) broken crockery, glass, metals(non combustible)

b) Special waste-Dead animals, abandoned vehicles, construction waste, pipes etc.

3. Industrial waste-packing materials, acids, dyes, plastics, sludge, metal scrap etc.

4. Agriculture waste-paddy husk, slaughter house waste, manure etc.

5. Special waste-Radioactive waste, toxic substances like pesticides, pharmaceuticals, inflammable corrosives, explosives etc.

MAJOR CONSIDERATIONS IN SOLID WASTE MANAGEMENT

1. Public Health-a) Solid waste-ideal breeding ground for rats, flies, mosquitoes, etc. which spread diseases.

b) Gases emitted from landfills& leaching of toxic substances to ground water also pose serious health risk.

2. Waste separation for recovery & recycling- Expensive metals such as some metals can be recovered.

And some like plastic can be recycled. This is important because of lack of space for disposing solid waste.

3. Energy recovery-

a) Direct burning of solid waste can recover energy in the form of heat.

b) Can be converted into fuel by anaerobic decomposition is another method.

c) Reusing of waste made of iron can save energy. This is because recovery of iron from ore requires lots of energy but recovery from scrap iron needs less energy.

TREATMENT & DISPOSAL OF SOLID WASTE

1. Auxiliary operations in solid waste management.

a) Collections, transport & handling-waste is collected from the sites, compacted to high density and transported to disposal sites.

b) Pulverization-Breaking down of waste into small particles using crushers.

c) Compacting & balling-Powdered waste is pressed together (compacted) into balls for easy transport and disposal.

MICROORGANISMS WHICH PLAY VITAL ROLE IN SOLID WASTE MANAGEMENT

a) Bacteria—They are important in decay of biodegradable waste. But some of them also cause diseases.

b) Fungi—They stabilize solid waste by decomposing plant tissue like cellulose & help in composting.

c) Protozoa—They eat up bacteria & maintain equilibrium by controlling the multiplication of bacteria in the waste.

d) Algae—Algal growth causes decrease in water quality. They also clog water sources, and their decay leads to loss of water quality

e) Viruses—in solid waste, they lead to spread of diseases.

WASTE TREATMENT & DISPOSAL

[In India, four main categories of waste are governed by separate ules:hazardous waste; radioactive waste; biomedical waste; and municipal solid waste]

I) Biodegradation of solid waste

a) Aerobic process—Composting

Decomposition of organic matter such as kitchen waste by micro organisms (bacteria and fungi) to give humus like substance is called composting. This can be used as manure.

It involves the following process

i) Waste preparation—Unwanted materials other than organic waste are removed. It is ground into required size, mixed with nutrient source (sewage sludge, animal manure, night soil)filler(wood chips etc. to allow air circulation) and water.

ii) Digestion—This is kept for 4 to 6 weeks, while turning it once or twice a week. During this period, the waste is decomposed by microorganisms.

iii) The decomposition process is aided by shredding the plant matter, adding water and ensuring proper aeration by regularly turning the mixture. Worms and fungi further break up the material. Aerobic bacteria manage the chemical process by converting the inputs into heat, carbon dioxide and ammonium. The ammonium is further converted by bacteria into plant nourishing nitrites and nitrates through the process of nitrification.

b) Anaerobic digestion is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen. It is used for industrial or domestic purposes to manage waste and/or to release energy.

The digestion process begins with bacterial hydrolysis of the input materials to break down insoluble organic polymers, such as carbohydrates, and make them available for other bacteria. Acidogenic bacteria then convert the sugars and amino acids into carbon dioxide, hydrogen, ammonia, and organic acids. Acetogenic bacteria then convert these resulting organic acids into acetic acid, along with additional ammonia, hydrogen, and carbon dioxide. Finally,methanogens convert these products to methane and carbon dioxide.^[2

Anaerobic digestion is widely used as a source of renewable energy. The process produces a biogas, consisting of methane, carbon dioxide and traces of other ‘contaminant’ gases.^[1] This biogas can be used directly as cooking fuel, in combined heat and power gas engines^[6] or upgraded to natural gas-quality biomethane. The use of biogas as a fuel helps to replace fossil fuels. The nutrient-rich residue left behind can be used as fertilizer.

Biogas is produced by the anaerobic digestion or fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, green waste, plant material, and crops.^[1] Biogas comprises primarily methane (CH₄) and carbon dioxide (CO₂) and may have small amounts of hydrogen sulphide (H₂S), moisture and siloxanes. In India, Pakistan and Bangladesh biogas produced from the anaerobic digestion of manure in small-scale digestion facilities is called gobar gas;

II) Sanitary Landfilling

a) Dumping waste in open pits. This leads to water pollution, bad smell, flies, rats etc. Not used now—This is unsanitary.

b)Burial of waste in closed pits

c) Layering—The Waste is compacted & put into pits & covered with soil everyday.

b&c are sanitary landfill methods because it reduces a lot of problems.

Ideal landfill site should be

a) Cheap and accessible

b) Should be well above ground water sources to prevent leaching.

c) Soil should not be harmful to environment.

d) Soil should be of low permeability so that gases, odours etc. cannot escape when waste is covered.

e) Shouldn’t be a problem to nearby homes, offices etc.

Problems with Landfilling

1. Economic problems—Land is lost. It cannot be used for farming or construction.

2. Aesthetic Problems—Bad odours, insects, rats, blowing papers plastic covers etc. cause problems if landfilling is not properly done.

3. Environmental problems:

a) Ground water contamination

b) Methane, CO₂, produced are harmful greenhouse gases. Methane is combustible, causing greater problems. Carbon dioxide leads to acid rain.

III) Thermal process

A. Incineration—Burning of solid waste

In this method solid waste is subjected to controlled combustion that converts the waste into incombustible solid residue and gaseous products. This method is used when suitable site for landfilling is not available and also to reduce the cost of transporting the waste through long distances for landfilling. It is also the preferred method for disposal of hazardous waste like hospital and biomedical waste. The most important problem faced during incineration is that toxic gases like dioxins and furans and large amounts of CO₂ and small amounts of other gases like SO₂, HCl, heavy metals and fine dust or flyash are produced during the process. These pollutants have to be removed from the flue gases by using electrostatic precipitators( Cottrell precipitator) to remove dust, catalytic converters to convert dioxins and oxides of nitrogen ( converted to ammonia) and by using acid or basic scrubbers to remove gases like CO₂, SO₂, HCl, etc. Heavy metals are removed by adsorption in activated charcoal.

Incineration reduces the solid waste to about 10-15% of original waste, sometimes even upto 3%. The solid mass of incombustible material remaining behind after combustion is called bottom ash.

Advantages:

· Volume of waste is reduced.

· Reduces land required for disposal

· Residue after incineration is not a source of pollution.

Disadvantages:

· High cost

· Air pollution

· Cannot be used for Radioactive waste.

Types of incinerators

a) Batch Type Incinerator-- A batch incineration is one in which refuse is charged, burned and residue removed in sequence prior to recharging of any additional refuse to the incinerator.

The operator charges the whole waste of one day amount into the incinerator as one lot. Because of no additional waste is added during the burning no excess air enters the combustion chamber. Thus we don’t have to control the air flow.

This type makes it possible to burn high polymer waste so far difficult to burn, and mixed waste of high polymer and common waste. It is also free from occurrence of black smoke and dust. Further, ash-take out and waste charge-in can be performed in the same work cycle to save manpower cost greatly.

Operation

The incinerator consists of a primary combustion chamber, a secondary combustion chamber, a primary burner and an auxiliary burner.

An operator charges the waste of one day into the incinerator and shuts the door. The door remains shut until the operation is complete.The burning operation starts only by pushing the switch button.

At first the secondary combustion chamber is pre-heated to a desired temperature by the auxiliary burner. When it has reached the required temperature the secondary combustion air blower is turned on so that there will be enough air in the secondary chamber for the complete combustion of the carbon in the waste gases that reach the secondary chamber. Thus the waste gases that are finally discharged will be smoke free and will contain less amount of CO. Also since high temperature is maintained throughout and it is not in contact with the ash the amount of persistent organic pollutants (POP) formed will be less. After ten seconds operation of the fan, kindling burner is ignited and the wastes being to burn. The burning of the wastes is controlled by adjusting the amount of primary combustion air supplied through the air nozzles at the lower side wall and the hearth of the furnace.
To make up for such adjusted down amount of primary air, secondary air is supplied to burn completely the waste gas in the secondary chamber. The combustion gas is heated by auxiliary burner in the reactor to burn carbon (which is the cause of black smoke), by supplying with sufficient air, and are discharged from exhaust stack in clean exhaust after complete burning. The wastes burns in the carbonaceous state for 4 to 7 hours after ignition, and at this stage, auxiliary burner is not used. Therefore, the wastes are burned only by forced air supply.
About 18 hours after starting, the operation finishes and the operator remove the ashes.

Features

1) The operators work is to remove the ashes and charge the wastes into the incinerator. So, the cost of operation is minimized.
2) There is no occurrence of black smoke and dust.
3) Various kinds of wastes can be burned together.
4) It doesn't need to crush and cut large sized wastes because of the spacious charge-in door.
5) This incinerator doesn't consume any water to treat gas. This means no need of any equipment to treat drainage.
6) This incinerators accessories are simple. It helps to save installation space.

b) Continuous Type Incinerator— A continuous incineration operation is one in which the charging of refuse and burning shall occur simultaneously and continuously. The heat produced during the burning can be extracted in a waste-to-energy plant which is an added benefit.

These types of incinerators come in many different types which are:

1) Moving grate incinerator—here the waste is fed to the top part of the hearth in the incinerator. As the hearth moves down the waste moves with it. As it moves it is burnt with the help of burners which supply heat from below as well as by auxiliary burners at the sides which also supply the excess air needed for complete combustion of the flue gases. Flue gases have to be kept at a high temperature of at least 850°C for at least 2 minutes in order to breakdown toxic organic compounds like dioxins produced by the combustion process. The heat from the flue gases is used to produce superheated steam which drives a turbine. Thus the heat can be converted to energy. The ash is continuously removed from the bottom part of the hearth.

2) The rotary kiln incinerator— The rotary kiln incinerator consists of a slightly inclined rotating primary combustion chamber. The waste is introduced at its highest end and the ash is removed at its lowest part. Due to its cylindrical form, the heat is equally refracted to the burning waste and the heat transfer and -control is optimal. Because of the continuous rotation and the inclination of the kiln, bottom ash is continuously and automatically evacuated. A rotary kiln is the most versatile incinerator available; it can treat a large range of wastes, varying from low to high calorific values and different particle sizes. The rotating primary chamber must be equipped with a static post combustion chamber, for achieving a complete burn out of the flue gases. The plant must be equipped with a flue gas treatment system, dry or wet - or a combination of both -before releasing the flue gases to the atmosphere. The acidic components are absorbed by sodium bicarbonate and dioxins and heavy metals absorbed by activated carbon. Flyash is removed either by a Cotrell precipitator or by scrubbing with water. Scrubbing also removes gases which are soluble in water. The water has to be further treated before release.

3) Static hearth incinerator-- The combustion of fumes/gas/liquids does not generate much ash and therefore a static hearth incinerator can be used.Liquid waste is pumped straight from the tanks to the incinerator.

4) Fluidized bed incinerator—this type of incinerator consists of a bed of sand over which the pre-treated waste is added. The sand and waste are kept suspended in air by the use of air currents and has a fluid characterlike the bubbling of a boiling liquid. This helps the complete mixing of the waste and air to ensure complete combustion.

5) Plasma arc incinerator—in this method an electric arc is struck between two electrodes to generate temperatures as high as 13900 in the arc column and about 2000 to 4500 degrees a few feet away. An inert gas is passed through the arc, and flows into the sealed container of waste material at very high temperature. Organic molecules (those that are carbon-based) become volatilized, or turn into gases mainly CO and H₂. This synthetic gas (syngas) can be used as a fuel source if properly cleaned. Inorganic compounds melt down and become vitrified, or converted into a hard, glassy substance. Metals melt down as well, combining with the rest of the inorganic matter (called slag).

Plasma waste converters can treat almost any kind of waste, including some traditionally difficult waste materials. It can treat medical waste or chemically-contaminated waste and leave nothing but gases and slag. Because it breaks down these dangerous wastes into their basic elements, they can be disposed of safely. The only waste that a plasma converter can't break down is heavy radioactive material, such as the rods used in a nuclear reactor

Waste	Technology
Medical/hazardous/industrial waste	Rotary kiln
D omestic / household waste	Moving grate
Liquid/gas/fluid waste	Static hearth
Homogenous waste (ex.WWTP sludge)	Fluidized bed
Unburnable waste (ex. Asbestos)	Plasma arc

B. Pyrolysis—Heating in a closed vessel under controlled temperature conditions

The Waste absorbs the heat & gets converted into useful products like tar, oil, useful fuel gases like hydrogen, methane, carbon monoxide& solid pure carbon char.

C. Recycling & Reuse.

D. Co-disposal—Disposal of solid waste along with other

waste like sewage sludge.

HAZARDOUS WASTE

It is defined by EPA under the Resource Conservation and Recovery Act (RCRA) as a waste material that can be classified as potentially dangerous to human health or the environment on the basis of any of the following criteria:

· It might ignite easily, posing a fire hazard.

· It might be corrosive, capable of damaging materials or injuring people.

· It might be reactive—likely to explode, catch fire, or give off dangerous gases when in contact with water or other materials.

· It might be toxic, capable of causing illness or other health problems if handled incorrectly.

· It might be on a list of specific wastes or discarded compounds that has been classified as hazardous

The Government of India has promulgated the Hazardous Waste (Management & Handling) Rules [HW (M&H)] in 1989 through the Ministry of Environment and Forests (MOEF) under the aegis of Environment (Protection) Act [E(P) Act], 1986. Under the HW (M&H) Rules, the hazardous wastes are divided into 18 categories.

1 Cyanide wastes

2 Metal finishing wastes

3 Waste containing water soluble chemicalcompounds of lead, copper, zinc, chromium, nickel, selenium, barium and antimony

4 Mercury, arsenic, thallium, and cadmium bearing wastes

5 Non-halogenated hydrocarbons including solvents

6 Halogenated hydrocarbons including solvents hydrocarbons

7 Wastes from paints, pigments, glue, varnish, and printing ink

8 Wastes from Dyes and dye intermediates containing inorganic chemical compounds

9 Wastes from Dyes and dye intermediates containing organic chemical compounds

10 Waste oil and oil emulsions

11 Tarry wastes from refining and tar residues from distillation or pyrolytic treatment

12 Sludges arising from treatment of wastewater containing heavy metals, toxic organics, oils, emulsions, and spent chemicals, incineration ash

13 Phenols

14 Asbestos

15 Wastes from manufacturing of pesticides and herbicides and residues from pesticides and herbicides formulation units

16 Acid/alkali/slurry wastes

17 Off-specification and discarded products

18 Discarded containers and container liners of hazardous and toxic wastes

Hazardous waste management is a new concept for most of the Asian countries including India which is a Party to the Basel Convention on transboundary movement of hazardous wastes. The basic objectives of the Basel Convention are control and reduction of transboundary movements of hazardous and other wastes subject to the Basel Convention, prevention and minimization of their generation, environmentally sound management of such wastes and active promotion of the transfer and use of cleaner technologies.

Health risks associated with hazardous waste disposal and management

a) Occupational health hazards—these include skin, eye , respiratory tract etc. infections from direct contact with the waste, dust or the combustion products, burns and wounds and chemical poisoning

b) Health hazard due to environmental contamination—these include pesticide poisoning from water run off from farms etc, and from contamination of ground water. They and other poisonous chemicals like synthetic organic compounds from industries can cause cancer. Heavy metals are also highly toxic. Electronic waste, like discarded parts of computers etc. generates toxic chemicals during burning

Hazardous waste management

a) Waste avoidance and waste minimization—

· The paper and pulp industry can shift to elemental chlorine free bleaching

· Mercury cell based caustic soda plant can shift to membrane cell process unit

b) Recycling of hazardous waste

· Electronic waste can be recycled

· Recycling of non-ferrous metallic wastes such as zinc dross, brass dross, used lead acid batteries

c) Self disposal

· Depending on the waste category, land disposal or incineration could be adopted

ALCHEMY--THE CHEMISTRY TEACHER BLOG

ENVIRONMENT CHEMISTRY –ELECTIVE COURSE

ENVIRONMENT CHEMISTRY –ELECTIVE COURSE

MODULE—I—ENVIRONMENT

Achievements of environmental NGOs with special reference to WWF (India),Teri, Clean (India), Sulabh International etc.

Module—III ATMOSPHERE

OZONE LAYER DEPLETION

Greenhose Effect and Global Warming

Module-IV-SOLID WASTE MANAGEMENT

3) Static hearth incinerator-- The combustion of fumes/gas/liquids does not generate much ash and therefore a static hearth incinerator can be used.Liquid waste is pumped straight from the tanks to the incinerator.

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