Strategies to control pollution - class-XI

Acid rain is the emission of oxides of sulphur and nitrogen in the atmosphere. This includes burning of fossil fuels containing sulphur and nitrogenous matter (such as coal and oil in furnaces and power stations, petrol and diesel in automobiles). 
Due to increase in acid gases in rain, the pH will change due to acid rain.

The Bhopal disaster or Bhopal gas tragedy was an industrial accident. It happened at a Union Carbide subsidiary pesticide plant in the city of Bhopal, India. On 3 December 1984, the plant released 42 tons of toxic methyl isocyanate (MIC) gas, exposing more than 500,000 people to toxic gases.

Sewage treatment is the process of removing contaminants from wastewater, primarily from household sewage. It includes physical, chemical, and biological processes to remove these contaminants and produce environmentally safe treated wastewater (or treated effluent).

The sewage treatment involves three stages, called primary, secondary, and tertiary treatment. First, the solids are separated from the wastewater stream. Then, dissolved biological matter is progressively converted into a solid mass by using indigenous, water-borne micro-organisms. Finally, the biological solids are neutralized, then disposed of or re-used, and the treated water may be disinfected chemically or physically (for example by lagoons and micro-filtration).

DDT, plastics, polythene, bags, insecticides, pesticides, mercury, lead, arsenic, metal articles like aluminum cans, synthetic fibres, glass objects, iron products and silver foils are non-biodegradable pollutants.

Methane (CH4) is the primary component of biogas produced during the anaerobic digestion process, making it an effective fuel.

Anaerobic digestion is a series of biological processes in which microorganisms break down biodegradable material in the absence of oxygen. One of the end products is biogas, which is combusted to generate electricity and heat, or can be processed into renewable natural gas and transportation fuels.

The waste materials which cannot be broken down into non-poisonous or harmless substances in nature are called non-biodegradable waste.
Examples are plastics, polythene bags, ball-point pen refills, synthetic fibres, and glass objects, metal articles like aluminium cans, iron nails, silver foil and radioactive wastes.

Biodegradable waste includes any organic matter in waste which can be broken down into carbon dioxide, water, methane or simple organic molecules by micro-organisms and other living things using composting, aerobic digestion, anaerobic digestion or similar processes.

The process of composting requires making a heap of wetted organic matter known as green waste (leaves, food waste) and waiting for the materials to break down into humus after a period of weeks or months.

Rainfall made so acidic by atmospheric pollution that it causes environmental harm, chiefly to forests and lakes. The main cause is the industrial burning of coal and other fossil fuels, the waste gases from which contain sulphur and nitrogen oxides which combine with atmospheric water to form acids.
These gases are released by automobiles, industries, power plants etc.

1. Recycling is the process of converting waste products into new products to prevent energy usage and consumption of fresh raw materials. Recycling is the third component of Reduce, Reuse and Recycle waste hierarchy. The idea behind recycling is to reduce energy usage, reduce volume of landfills, reduce air and water pollution, reduce greenhouse gas emissions and preserve natural resources for future use.

2. A landfill site (also known as a tip, dump, rubbish dump, garbage dump or dumping ground and historically as a midden) is a site for the disposal of waste materials by burial and is the oldest form of waste treatment (although the burial part is modern; historically, refuse was just left in piles or thrown into pits).

3. Incineration or combustion is a type disposal method in which municipal solid wastes are burned at high temperatures so as as to convert them into residue and gaseous products. The biggest advantage of this type of method is that it can reduce the volume of solid waste to 20 to 30 percent of the original volume, decreases the space they take up and reduce the stress on landfills.

1. Recycling is the process of converting waste products into new products to prevent energy usage and consumption of fresh raw materials. Recycling is the third component of Reduce, Reuse and Recycle waste hierarchy. The idea behind recycling is to reduce energy usage, reduce the volume of landfills, reduce air and water pollution, reduce greenhouse gas emissions and preserve natural resources for future use.
2. Incineration or combustion is a type disposal method in which municipal solid wastes are burned at high temperatures so as to convert them into residue and gaseous products. The biggest advantage of this type of method is that it can reduce the volume of solid waste to 20 to 30 percent of the original volume, decreases the space they take up and reduce the stress on landfills.

3. Anaerobic digestion is a collection of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels.

Industrial wastewater treatment describes the processes used for the treatment of wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment.

Phytoremediation, or using plants (such as willow) to extract heavy metals can be an effective method to prevent soil pollution.

Silicone coated fiberglass bags are resistant to high temperatures and are able to separate at a temperature range of approximately $-50^oC$ to $+250^oC$. Thus it has excellent weather proof and water repellent properties. It is also resistant to chemicals. It is used to filtering hot gases as it can withstand high temperatures.

AK-33-X is a known commercial additive used as an antiknock agent in unleaded petrol to replace the toxic Tetraethyl lead.

A sedimentation tank allows suspended particles to settle out of water or wastewater as it flows slowly through the tank, thereby providing some degree of purification. A layer of accumulated solids, called sludge, forms at the bottom of the tank and is periodically removed.

Minamata disease is a neurological syndrome caused by severe mercury poisoning. Minamata disease was first discovered in Minamata city in Kumamoto prefecture, Japan, in 1956. It was caused by the release of methylmercury in the industrial wastewater from the Chisso Corporation's chemical factory, which continued from 1932 to 1968. This highly toxic chemical bio accumulated in shellfish and fish in Minamata Bay and the Shiranui Sea, which, when eaten by the local populace, resulted in mercury poisoning.

Deep injection is a liquid waste disposal technology. This alternative uses injection wells to place treated or untreated liquid waste into geologic formations that have no potential to allow migration of contaminants into potential potable water aquifers.

Other methods result into pollution and are not a feasible solution. 

Carbon dioxide and carbon monoxide gases are emitted during the combustion of various fuels. Carbon monoxide is poisonous, whereas carbon-dioxide is non-toxic in nature. Carbon monoxide is poisonous because it is capable of forming a complex with hemoglobin (carboxyhaemoglobin), which is more stable than the oxygen-haemoglobin complex. The concentration range of 3–4% of  carboxyhaemoglobin decreases the oxygen-carrying capacity of blood. This results in headaches, weak eyesight, nervousness, and cardiovascular disorders. A more increased concentration may even lead to death.

Carbon monoxide when binds to hemoglobin forms a stable compound - carboxyhaemoglobin. Since, oxygen of carbon monoxide binds more readily to hemoglobin than do Oxygen of carbon dioxide, therefore carbon monoxide prevents carbon dioxide from binding to Hb, which means diffusion or exchange of gases won't take place at alveolar site. So, carbon monoxide is more harmful because it prevents oxygen from entering the body.

In situ vitrification (ISV) is a process which uses an electric current to melt soil or other earthen materials at extremely high temperatures and thereby immobilize most inorganics and destroy organic pollutants by pyrolysis. While other methods can be successfully used to dispose hazardous wastes, ISV will cause air and soil pollution.

Reducing the volume and/or hazard of the waste, long-term storage or disposal, dumping at sea are ways of managing hazardous wastes. Reducing the production of waste while increasing the amount generated is a preventive method rather than a disposal method.

Physical treatment of water includes-filtration, sedimentation, separation etc. Chemical and Biological treatment includes coagulation, flocculation, ion-exchange, absorption, also aerobic treatments and anaerobic treatments. By these treatments, all physical, chemical and biological matter that contaminates wastewater, can be removed 

Water treatment plants should be installed in all industrial areas. Laws for industrial units should be strictly implemented so that polluted water is not disposed off directly into rivers and lake.

The gas obtained by decomposing sludge is Biogas (methane and carbon dioxide). Decomposition of sludge products methane and carbon dioxide which is then stored and supplied as biogas for various household processes and other commercial processes.

Mycoremediation is a form of bioremediation, the process of using fungi to degrade or sequester contaminants in the environment. Stimulating microbial and enzyme activity, mycelium reduces toxins in-situ. Some fungi are hyperaccumulators, capable of absorbing and concentrating heavy metals in the mushroom fruit bodies.

Industrial waste is the waste produced by industrial activity which includes any material that is rendered useless during a manufacturing process such as that of factories, industries, mills, and mining operations. It has existed since the start of the Industrial Revolution. Some examples of industrial wastes are chemical solvents, paints, sandpaper, paper products, industrial by-products, metals, and radioactive wastes.

Waste management is the precise name for the collection, transportation, disposal or recycling and monitoring of waste. This term is assigned to the material, waste material that is produced through human being activity. This material is managed to avoid its adverse effect on human health and environment.

Sludge is a semi-solid slurry and can be produced as sewage sludge from wastewater treatment processes or as a settled suspension obtained from conventional drinking water treatment and numerous other industrial processes.

Non-biodegradable waste is a type of waste that can not be broken down into its base compounds by micro-organisms, air, moisture or soil in a reasonable amount of time. Non-biodegradable waste is an environmental concern, as it threatens to overwhelm landfills and create disposal problems. Almost all industries generate some amount of non biodegradable waste for eg fly ash,slag,mud which are major concern for the environment.

Paint is created in factories and non-bio-degradable waste. It is an industrial waste.