Mechinopedia For Mechanical Engineers

CHERNOBYL NUCLEAR DISASTER (NUCLEAR POLLUTION) :  In April 26,1986, the melt down of the Chernobyl nuclear reactor , in Russia, has leaked out the radioactive rays and radioactive materials.   Effects : 1. In this Pollution nearly 2000 persons have been killed by the accident. 2. People suffered due to the illness such as, degeneration of the cells, severe bleeding, anemia, skin cancer. 3. Animals, Plants are also affected by nuclear radiation.  MINAMATA EPIDEMIC (1953) : MARINE POLLUTION ( CASE STUDY ) Minamata is a small coastal village in Japan. The Chisso Chemical Company , which produces vinyl polymer plastics used organomercurial compound. The industry released its effluent into Minamata sea. The effluent containing mercury ions is converted into methyl mercury, which is highly toxic.  The marine organisms like phytoplankton and zoo-planktons easily absorb the toxic methyl mercury compound. These organisms are consumed by small fishes and these are in turn consumed  by large

There are nearly 500 dying units and 195 bleaching units operating in and around Tirupur. They consume large quantity of  water for processing and later discharge waste water.  The effluent from the  above Industries affect the surface and underground water and make the water unfit for domestic work. The effluent also increase the pH of the soil and affect the cultivation. The rivers like Bhavani, Noyal and Cauvery get polluted due to mixing of effluent from the above industries. Tamil Nadu Pollution Control Board ( TNPCB ) has directed all textile printers and dyers of Tirpur to not allow the effluent to mix in the river systems. 

  Palar River- Pollution : Palar River Orginates in Nandidurgam of  Karnataka state and flows for about 350 km through Karnataka, Andhra Pradesh and Tamil Nadu. Palar Supply drinking water for the several municipalities, towns and villages in Vellore District, Tamil Nadu.  Now the Palar is polluted by the effluent of various leather industries which in turn affecting the agricultural productivity in 40,000 hectares of croplands.  Type of Pollutants :  Chrome Tanning industries discharge large amounts of chemicals like chromium, calcium, ammonium salts, organic dyes and acids. 

We know that the mercury is an extremely toxic metal. thermometer manufacturing company releases very small amount of mercury (from 0.1 mg to 10mg per 1 kg of soil sample) into the atmosphere, which contaminates the soil. Hindustan lever Ltd. (HLL) : Hindustan Lever Ltd (HLL), Kodaikkanal, is manufacturing thermometer, disposed its mercury laden glass waste into nearby area and created land pollution. By the intervention of local people and environmental groups 

 The coca cola's bottling unit  at plachimada, Palakkad district, Kerala, discharged large amount of sludges. These sludges are used as fertilizers by the near by farmers.  But, analysis of the sludge showed  that it contains, toxic metals like cadmium and lead. The scientists warned at the level of these toxic elements would pollute the land, local water supplies and the food chain.  

The west Bengal, Bihar and Bangladesh are severely contaminated by toxic heavy metal arsenic. Effect : 1. The local People, who were ingesting low doses or 10 - 14 years, were affected from white or black spots on the skin, called melanosis.\ 2. Long exposures lead to bladder and lung cancer. 3. Children are more badly affected by arsenicosis. Sources :  Excessive use of  lead arsenate and copper arsenite as pesticides in summer paddy and jute crop seems to be the major cause of  arsenic pollution. Examples :  The states lying in the down stream side of  the  river Ganga are facing the problem of  arsenic content. Nearly 350 million residents in Ganga basin are exposed to dangerous levels of the arsenic element in their drinking water.  \

 The world's worst industrial accident occurred in Bhopal city, M.P. on the night of 3rd December 1984.   It happened at Union Carbide India Ltd, who manufactures some carbonate pesticides, using methyl   isocyanate (MIC). The reactor got exploded, due to failure of  its cooling system and 40 tons of MIC leaked into the  atmosphere.  Effect :  I) Methyl-iso-cyanate is a toxic gas, lower concentrations of which affects lungs and eyes and causes Irritation in the skin. II) Higher Amounts of MIC, remove oxygen from the lungs and can cause death. Effects in Bhopal :  The gas (MIC) spread over 40 sq.km area. About 5000 persons were killed and 65000 people suffered from severe eye, respiratory, neuromuscular, gastrointestinal disorders. Nearly 1000 persons become blind. 

The Taj Mahal is the "King Emperor" amongst world wonders. It represents the most refined aesthetic value and one of the most priceless national monuments and also a glorious reputation to the men's achievements in architecture and engineering. The Foundries, The chemical and hazardous Industries and also the refinery at Mathura are the major sources of  Damage to Taj. The So3, emitted by the Mathura refineries, combined with oxygen along with moisture in the atmosphere forms sulphuric acid, called acid rain. This has a corroding effect on the clean white marble.  Industrial waste, refinery emissions, brick kilns, vehicular traffic and generator set are primarily responsible for polluting the ambient air around the Taj Trapezium Zone ( TTZ). Both inside and outside, the marble has decayed a yellow pallor is affecting the entire monument.  

A leading petroleum refinery, The Madras Refineries Limited (MRL) located in Chennai has taken important steps in managing the effluents discharging efficiently. The MRL has two efficient treatment plants designed to meet IS2490 quality control standards. The Ministry of Environment and Forests has developed an industry oriented standards called MINAS (Minimum National Standards)  as per the Environment Protection Act, 1986.                    At the new plant, the treatment facilities consists of  three  streams. 1. The first is cooling water treatment. 2. The second is treating sour and merox water and  3. The third is for treating floor wash and stream water and to remove oil. The three efficient streams from the refinery contain the following contaminants. 1. Process and utility stream : The contaminants are oil, grease, hydrogen sulphide, phenols, acids and alkalis. 2. The storm and wash water stream : Oil and grease. 3. The general purpose stream : Waste water, solids, organic

Since Nuclear wastes are extremely dangerous the way in which they are disposed is strictly controlled by international agreement. Classification Of  Radio Active Wastes : The Nuclear Wastes are usually classified into three categories. 1. High level Wastes (HLW) 2. Medium Level wastes (MLW) 3. Low level Wastes ( LLW)  I) HIGH LEVEL WASTE (HLW) : Examples : Spent Nuclear Fuel. HLW have a very high radioactivity per unit volume. They have to be cooled and stored for several decades by its producer before disposal. Since they are too dangerous, must be contained either by converting them into inert solids (ceramics)  and then buried deep into earth or stored in deep salt mines.  II) MEDIUM LEVEL WASTE (MLW) : Examples : Filters, reactor components, etc.,  MLW are solidified and are mixed with concrete in steel drums before being buried in deep mines or below the sea bed in concrete chambers. III) LOW LEVEL WASTES (LLW) : Examples : Solids or liquids contaminated with traces of radioac

Radiation Hazard in the environment comes from ultraviolet, visible, cosmic rays and microwave radiation which produce genetic mutations in man. The biggest hazard comes from X-rays which accounts for 95% of out radiation exposure other than cosmic rays.  Sources of  Nuclear Hazards :  Various sources of  Nuclear Hazards are grouped into two types  1. Natural Sources  2. Man - made ( Anthropogenic ) sources.  I) NATURAL SOURCES :  a) The very important natural source is space, which emit cosmic rays. b) Soil, rocks, air, water, food, radioactive radon-222 etc., also contain one or more radioactive substances.  II)MAN - MADE SOURCES :  Man - made sources are nuclear power plants, X-rays, Nuclear Accidents, Nuclear Bombs, Diagnostic kits etc., where radioactive substances are used.  EFFECTS OF NUCLEAR HAZARDS : Studies have shown that the health effects due to radiation are dependent on the level of dose.  1. Exposure of the brain and central nervous system to high doses of radiation cau

Thermal Pollution is defined as the addition of excess of undesirable heat to water that makes it harmful to man, animal or aquatic life or otherwise causes significant departures from the normal activities of aquatic communities in water.  SOURCES OF THERMAL POLLUTION :  1. Nuclear Power plants  Nuclear power plants including drainage from hospitals, research institutes, nuclear experiments and explosions, discharged a lot of utilized heat and traces of toxic radio nuclides into nearby water streams.  2. Coal - fired power plants  Some Thermal power plants utilize coal as fuel, while a few plants use nuclear fuel. Coal - fired power plants constitute the major source of thermal pollutants. 3. Industrial effluents  Industries like textile, paper and pulp as well as sugar also release heat in water but to a much lesser extent.  4. Domestic sewage  Domestic sewage is commonly discharged into rivers, lakes , canals or streams with or without waste treatment.  5. Hydroelectric Power. Gener

Noise pollution   is defined as, the unwanted, unpleasant or disagreeable sound that causes discomfort for all living beings.                      Unit Of  Noise ( Decibel ) :  The sound intensity is measured in decibel (dB), which is one tenth of the longest unit Bel. One dB is equal to the faintest sound, a human ear can hear.  Noise level : Normal conversation sound ranges from 35 dB to 60 dB . Impairment of  hearing takes place due to exposure to noise of 80 dB or more. Noise above 140 dB becomes painful.  Types and Sources (causes) Of  Noise : It has been found that environmental noise is doubling every 10 years. generally noise is describes as,  1. Industrial noise - Heavy industrial machines etc., 2. Transport Noise  - Unwanted horns and sounds 3. Neighbor hood noise - Speakers etc.,                  Effects of Noise Pollution :  i) Industrial pollution affects human health, comfort and efficiency. It causes contraction of blood vessels, makes the skin pale, leads to excessive s

Marine Pollution is defined as, " the discharge of waste substances into the sea resulting in harm to living resources, Hazards to human health, hindrance to fishery and impairment of quality for use of sea water."                           SOURCES (OR) CAUSES OF MARINE POLLUTION : 1. Dumping the wastes.  The most serious issue is dumping of untreated wastes and sewage into oceans by the coastal towns and cities and industrial units. All That what is carried by rivers ultimately ends up in the seas. On their way to sea, rivers receive huge amounts of sewage, garbage, agricultural discharge, pesticides, including, heavy metals. These all are added to sea. Huge quantity of plastic is being dumped in sea.                   2. Oil Pollution of Marine Water : The great damage to water is imposed by petroleum and its products.  Heavy petroleum products precipitate to the bottom or are adsorbed on rock, stone, and sand banks to inhibit the life of the hydrobionts. One drop of  petro

STEPS INVOLVED IN SOLID WASTE MANAGEMENT :  1. Solid Waste Generation.  2. Collection of Waste 3. Transportation  4. Storage            5. Segregation of  Wastes - Home Separation For Recycling. 6. Disposal Wastes. Methods Of  Disposal Of Solid Waste :  1. Landfill. 2. Incineration. 3. Composting.  I) LANDFILL : Solid wastes are placed in sanitary landfill system in alternate layers of 80cm thick refuse, covered with selected earth fill of 20cm thickness. After two or three years, solid waste volume shrinks by 25 -30 % and the land is used for parks, roads and small buildings.  The most common and cheapest method of waste disposal is dumping in sanitary land - fills which is invariably employed in Indian cities. land - fill structure is built either into the ground or on the ground into which the waste is dumped. The method involves spreading the solid waste on the ground, compacting it and then covering it with soil at suitable intervals . II) INCINERATION (or) THERMAL PROCESS : It is

Rapid population growth and urbanization in developing countries have led to the generations of enormous quantities of solid wastes and consequential environmental degradation. An estimated 7.6 million tones of  municipal waste is produced per day in developing countries. These wastes are disposed in open dumps creating considerable nuisance and environmental problems. These are potential risks to health and to the environment from improper management of solid wastes. management of  Soil waste is therefore, become very important in order to minimize the adverse effects of solid wastes. Types and Sources of Solid wastes :  Depending upon nature, solid wastes can be broadly classified into three types 1.Urban or Municipal Wastes 2.Industrial Wastes  3.Hazardous Wastes I) Sources of Urban Wastes :  a) Domestic wastes - food waste, cloth , waste paper, glass bottles, polythene bags, waste metals, etc. b) Commercial Wastes - waste paper, packing material, cans , bottle , polythene bags etc.